Vector Magazine, 5th Edition, November 2022

Vector T he SPS ST EM Jour nal

Fifth Edition 1

Alexander Apkarian

Editor-in-Chief

Noah Whale

Deputy Editors

Zak Farazi Astronomy

Vikram Bhamre Kai Philipose

Biology

Ryo Kusakari Thomas Hallé

Biotechnology Ynon Weiss Book Reviews

Yuxi Liu Alexis Andronikos

Chemistry

Luca Viviano Dom Yap

Computer Science

Harishan Ganeshan

Charles Calzia Engineering

Rahul Marchand

Environmental Science

Frederick Dehmel Gabriel Treneman

Maths

Shashwat Sangwan Leo Wen

Medicine

Oliver Milroy-Goulding

News

Marco Cina Rabin Adrien Durantel

Physics

Teddy Onslow Shivan Arora Psychology

Varun Vashisht

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Editor ial Welcome, readers, to the fifth edition of Vector, the St Paul's STEM journal. It has been a privilege to lead a large team of talented peers in collaboration with our dedicated teachers. I would like to sincerely thank all of those involved.

greater integration with literature and philosophy. Effective communication in science is of paramount importance if the public are ever to actualize the extent of ground-breaking discoveries.

Moreover, it is critical that the fidelity of scientific work is held to the highest possible standard ? both to advance science and to maintain the public?s trust. Famous missteps include the false claims about cold fusion in the 1980s, Andrew Wakefield?s infamous paper on MMR vaccines, and the cancer-causing potential of powerlines in the 1990s.

This year?s edition was conceived and edited in a somewhat unconventional fashion; I began the work in London and completed it in California during a 10-week research stint.

Although this complicated logistics, it strengthened the publication. Working in a laboratory enabled me to bounce ideas off several highly esteemed researchers who were able to provide invaluable feedback.

A lack of rigour and skilled communication within the scientific field has, in great part, led to the ?irreproducibility crisis.?

Reproducibility is key as it allows peers to review, confirm, and build upon work. The universal aim to publish papers soon after a discovery (driven by a ?publish or perish? environment) should be balanced with the quality of scientific research and the clarity of papers. Below is the result of a meta-study concerned with irreproducibility in science.

The title, Vector, has always fascinated me.

Derived from the latin ?Vehere?, meaning to carry, its scientific usage varies according to discipline. In mathematics, physics, and engineering, a vector conveys magnitude and direction. In biology it denotes a vehicle used to carry foreign material into a cell.

In an increasingly complex and interconnected world, the most profound scientific advancements will come from interdisciplinary approaches.

We see evidence of the significance of multidisciplinary perspectives all around us.

The discovery of the DNA double helix was only fully harnessed due to parallel developments in computational power, information theory, and powerful algorithms.

Likewise, the record-breaking speed of vaccine developments during Covid required breakthroughs in both biology and computer science ? AI programs were used to design mRNA molecules.

In order to effectively combat this ?crisis?, we must foster interdisciplinary and rigorous environments. The separation between STEM and humanities should not act as a closed, but rather a permeable, barrier, allowing for the sharing of ideas and themes, ensuring effective scientific communication.

Whilst some will confine this multifaceted approach to within STEM disciplines, the scientific world would greatly benefit from

Alexander Apkarian 3

Contents Astr onomy Astronomy Society: Observing The Sun page 5

The Chemistry Behind Acne page 24 The Biochemistry of Coffee page 26

Biology

Computer Science

Myostatin and Its Role in Doping page 7

The Illusion of the Third Dimension and the Tropes of Modern First Person Shooters page 28

The Key to Eternal Youth? The Technique that Rewound the Age of Skin Cells by 30 Years page 9 Clash of the Titans: Spinosaurus vs Tyrannosaurus page 11 Mendel's Discoveries in the Understanding of Complex Diseases page 13

Biotechnology Mycoremediation: How Fungi Can be Used to Clean the World page 15 Lipid Nanoparticles: A New Era of Vaccines page 16

Book Reviews The Emperor of All Maladies By Siddhartha Mukherjee page 19 A Brief History of Time By Stephen Hawking page 20

Chemistr y The Catalytic Condenser Chameleon Device: Appreciating the Value of Metal Catalysts page 22

How does a Bayesian Neural Network Model Differ from a Traditional Point-Estimate Neural Network? page 29 The Travelling Salesman Problem page 31

Engineer ing "EJECT! EJECT!" page 33 The Future of the Factory page 34

Envir onmental Science Constructing a 'Simple' Climate Model page 36

Mathematics Catalan Numbers page 38 A Combinatorial Proof of Wilson?s Theorem page 39

Medicine The Future of Artificial Intelligence in Medicine page 42

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A Life for a Life: Xenotransplantation page 43 Human vs Disease page 45

News Can Mistletoe Berries be Used as a Superglue? page 46 How do Hypergiants Die? page 46 A New Black Hole? page 47 Do Mummies Still Contain Ancient Strains of Bacteria? page 47

Physics The Doppler Effect page 48 Quantum Computing: Separating Fact from Myth page 49 Centripetal Force page 51

Psychology What is Addiction? page 53 Does Language Affect the Way in Which We Think? page 54

Astr onomy Astr onomy Society: Obser ving the Sun Danny Cui In June of 2022, right the end of the summer term, the Astronomy Society completed its first-ever observation of the Sun. This viewing was successful and we were even able to see some of the details on the Sun's surface ? most notably sunspots and solar filaments.

surrounding penumbra is brighter and has a temperature of around 5,500°C. Sunspots often come in pairs of opposite magnetic polarity. Below is a photo that was taken during our observation. It illustrates a solar filament in the bottom right corner, a pair of sunspots, and the curling of the sunspots' surroundings with the pattern of their magnetic fields.

But what are sunspots and solar filaments?

How do solar activities like these affect us?

How does the equipment used to observe the Sun work?

Solar filaments are structures of plasma and magnetic fields which extend outwards from the photosphere (the deepest observable region of the Sun?s surface). They often form in the shape of a loop owing to their underlying magnetic field and can extend from 50,000 to 70,000 km into the corona (the outermost part of the Sun?s atmosphere). Given that their plasma is much cooler than that of the corona, solar filaments usually appear as dark line segments on the Sun?s surface.

Sunspots, as the name suggests, are dark spots on the surface of the Sun. They are minima of temperature on the Sun?s surface, caused by concentrations of magnetic flux, which prevent convection currents in the Sun from transferring heat to their surroundings. Sunspots have two main structures ? the umbra (a central region) and the penumbra (a surrounding region). The umbra is the darkest area of the sunspots, and the coolest area ? roughly around 2,700°C to 4,200°C. This is because the magnetic field is at its strongest. The

Sunspots form where strong magnetic fields emerge from the Sun?s interior. These strong magnetic fields catalyse other solar activities which accompany periods where a large number of sunspots appear. These activities include solar flares, where intense localised electromagnetic radiation on the Sun's atmosphere erupts owing to acceleration of charged particles in the Sun caused by stored magnetic energy in the sun?s atmosphere; coronal mass ejections, where large amounts of plasma are released due to intense magnetic activity on the Sun into the solar

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owing to the atmosphere. Subsequently, we used a stacking software which used a point of reference in the image to align and combine the frames. Usually, only the best 50% of frames are used, as the blurred frames will only downgrade the final product.

The image is then sharpened in image processing software. To do this, a histogram of the data is manually altered to enhance the detail on the sun, after which a noise reduction algorithm is applied. Finally, the individual red, green and blue channels of the image are tweaked to artificially give colour.

This is up to the preference of the user, and some people like darker, redder versions of the Sun while others prefer a lighter edit.

wind; and other solar phenomena. These periods of intense solar activity, referred to as ?solar maxima?, occur in regular periods of roughly 11 years. This is called the solar cycle, where the magnetic polarity of the Sun flips periodically.

Some coronal mass ejections (CMEs) result in large amounts of plasma travelling towards the Earth, carrying with them a strong magnetic field. The shock wave of the travelling plasma compresses the Earth?s magnetic field, and its magnetic field interacts with that of the Earth's, storing energy in the Earth?s magnetosphere. This is called a geomagnetic storm. Energy in the magnetosphere increases plasma movement, increasing current. This energy can also induce electric currents in our power grids and other grounded conductors. This can cause instability in power transmission networks and result in the burning out of transormers. Given our dependancy on electricity, this is highly problematic.

However, solar activity can also manifest itself in stunning ways. For CMEs which exude smaller amounts of plasma travelling towards the Earth, the plasma, being charged particles, is deflected by the Earth's magnetic field and towards the north and south poles. These charged particles then collide with oxygen and nitrogen atoms, releasing energy in the form of colourful light, creating an aurora.

If you are interested in extraordinary activities related to astronomy like this one, be sure to email Dr Gane, or come to P4 on Tuesday lunchtimes at 1:00 pm. Lastly, the astronomy society wants to thank our financial supporters who have given us the money to buy the equipment.

We observed these details on a telescope equipped with a hydrogen-alpha filter, which allows for only a specific range of light wavelengths. This is critical as it limits the light-collecting power of the instrument, making the image observed safe to the eye.

We also captured images in calcium-K or visible light to highlight different features of the sun. We first captured thousands of frames of the Sun through a monochrome camera with the shortest possible exposure time. For each image, the exposure time is kept to a minimum to prevent any blurring 6

Biology Myostatin and I ts Role in Doping H ugo L efr anc Doping is now a global problem for major sporting events. Sports federations, led by the International Olympic Committee, have, for the past half century, unsuccessfully attempted to halt its spread . It was expected that educational programs, testing, and supportive medical treatment would decrease this behaviour. Unfortunately, this has not been the case. In fact, new, more powerful, and undetectable doping techniques are now abused by athletes.

Simultaneously, even more sophisticated distribution networks have developed.

performance enhancing drugs were particularly fascinated by it. There were many questions being asked, but most importantly, could the role of myostatin be useful in the world of doping?

Myostatin is a molecule discovered in 1997 by a team working on the Transferring Growth Factor-B (TGF-B) hormone family using a technique called degenerative PCR. It signals through the activin receptors and functions as a negative regulator of skeletal muscle growth.

The first thing to note is that unlike mTOR (the start button for muscle growth), myostatin signalling is specific to the muscle; this is a good start for any prospective dopers as it means that a molecule that targets myostatin will only affect the desired part of the body. Also, the myostatin pathway encompasses a range of possible doping targets other than myostatin itself.

The TGF-B group ran numerous in vitro functional assays using mouse models. The knockout mice without functional myostatin survived but with an altered biology that clearly pointed to the role of myostatin in the body: they had 200% more muscle mass than the control mice owing to an increase in the size of muscle fibres and in the number of myocytes. A similar phenotype is seen in some breeds of cattle known to be genetically ?double muscled?, for example the Belgian Blue. It was subsequently noticed that a five year old boy who had a dramatic increase in muscle mass was found to have a defect in his myostatin gene. Following this, interest in myostatin significantly increased.

Athletes and bodybuilders in search of

To become effective in muscle cells, myostatin needs to be modified by other proteins. These proteins, called proteases, degrade myostatin, making it an optimum size for activity. Once active, myostatin binds to proteins on the muscle cell surface that then bind to the TGF-B hormone receptors.

Myostatin binding activates these receptors, allowing them to phosphorylate two proteins in the cell called SMAD2/3 and SMAD4.

These then bind to the nucleus and to specific parts of the DNA ? and by an as of yet unknown mechanism ? switch off muscle protein synthesis. This illustrates the

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complex process associated with protein synthesis supression in muscles. It also demonstrates that there are mutliple targets for myostatin restriction.

by cachexia, a symptom of cancer that causes the loss of muscle and fat despite adequate nutrition. Some studies in mouse models suggest that myostatin inhibition may prevent cancer-related muscle loss in both lung and skin cancer (melanoma). This suggests that myostatin inhibition should be further researched for the prevention of catexia-related deaths in humans.

However, myostatin inhibition does not come without side effects. Firstly, increased muscle growth will lead to an increased risk of injury owing to stress on the muscle fibres. This may be especially true for individuals using myostatin inhibitors as workout supplements instead of as a medical treatment for muscular dystrophy or other disorders. Other possible side effects include increased chance of tendon rupture, heart failure due to inflamed cardiac muscle, and rhabdomyolysis (a breakdown of muscle fibres that often leads to kidney failure). It is clear that myostatin inhibition can play a critical role in doping. The plethora of targets for myostatin signalling supression, along with its various benefits, makes myostatin inhibition a very attractive process to potential dopers. However, this has side effects. Nonetheless, a survey conducted by Dr Robert Goldman claims that over 50% of athletes would take a drug that guaranteed them unlimited, undetectable sporting victories for five years, even if it was followed by instant death. Thus, myostatin could be a very attractive target for doping in the future.

Since its discovery, pharmaceutical companies have produced myostatin ? inhibiting drugs to treat diseases such as muscular dystrophy. However, this means that such drugs are available to athletes and bodybuilders who would look to consume these to improve their muscle mass ? a key attribute in many sports. One such drug produced is Stamulumab. This is a G1 immunoglobulin antibody which binds to myostatin and prevents it from binding to its target site, thus inhibiting the growth-limiting action of myostatin in muscle tissue. In 2019 it was added to the World Anti Doping Agency's list of prohibited drugs as it was feared it gave competitors too much of an advantage.

However, as with most prohibited drugs, this doesn?t remove the threat of usage, and as a result it is still being consumed throughout the world by athletes.

But what does myostatin inhibition actually do? As we saw earlier, its main effect is that it reduces muscle loss during inactivity and can also help build muscle. However, scientists also believe that myostatin inhibition may prevent muscle loss from diseases such as muscular dystrophy. In addition, over 20% of cancer deaths in human patients are caused

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T he K ey to Eter nal Youth? T he Technique that Rewound the Age of Skin Cells by 30 Year s K ai Philipose Cracking the code of why we age and how to reverse it has been the Holy Grail for scientists, and, in recent years, for billionaires seeking to literally buy more time to spend their ever-increasing mountains of wealth. Luckily for them, as well as us, a team of researchers from the Babraham Institute in Cambridge seems to have brought us one step closer to this goal.

in other cells of the body, this was be disproven by Dr John Gurdon?s pioneering experiment in 1962.

Dr Gurdon showed that differentiated nuclei from tadpole intestinal or muscle cells could be transferred into enucleated Xenopus eggs and give rise to mature and fertile male and female frogs that showed no signs of premature ageing. Just like the fused nucleus of the sperm and egg during fertilisation, the somatic nucleus was reprogrammed and any hallmarks of ageing were reset. Therefore, in principle, there must be a mechanism which we could utilise to reverse the molecular attributes of ageing and phenotypically rejuvenate somatic cells.

What is ?ageing?? Ageing can be defined as the gradual decline in organismal fitness that occurs as a consequence of the molecular ?hallmarks? of ageing: telomere attrition, genetic instability, epigenetic and transcriptional alterations, and an accumulation of misfolded proteins. Thus, many of the symptoms we associate with ageing are a direct consequence of these molecular hallmarks. For example, loose wrinkly skin is caused by the dysfunction of skin fibroblasts in the dermis. With age, they produce less collagen, elastin, and growth-promoting factors that create the foundation of a healthy, plump epidermis (the visible layer of the skin).

Enter Yamanaka Factors.

Discovered by Shinya Yamanaka in 2006, these four transcription factors (Oct3/4, Sox2, Klf4, c-Myc) can turn differentiated adult cells into pluripotent stem cells in a process called induced pluripotent stem cell (iPSC) reprogramming. iPSC reprogramming has shown to be able to reverse many age-associated changes, including telomere attrition and oxidative stress. Unfortunately, however, it also results in the loss of original cell identity and so function. To avoid this, researchers from the Babraham Institute decided to take another approach, where the Yamanaka factors are only expressed for short periods of time. This novel strategy called transient reprogramming was able to achieve a ?robust and very substantial rejuvenation? of around 30 years in fibroblasts without loss of cell identity.

So how might we reverse ageing?

Perhaps the idea of turning back time on our cells seems preposterous, however, the resetting of the ageing clock is a frequent, deeply installed process that is crucial to the nature of life: it occurs with every fertilisation event. For humans, this involves the fusion of two cells, a sperm and an egg, each of whose chronological age is measured in decades, to give rise to a zygote which somehow has no trace of the parental cells' age. Although one might make the argument that the mechanism by which these germ cells fuse and then rejuvenate is specific and so not replicable

iPSC reprogramming consists of three phases: the initiation phase (IP), where somatic expression is repressed; the maturation phase (MP), where certain

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pluripotency genes become expressed; and the stabilisation phase (SP), where the complete pluripotency program is activated.

Previous methods of transient reprogramming had only reprogrammed within the IP, but researchers were able to show that further reprogramming up to the MP may achieve greater rejuvenation.

fibroblasts).

Transient reprogramming improved the median migration speed, although there some speeds were unaffected. Overall, the results showed that maturation phase transient reprogramming (MPTR) rejuvenates multiple molecular hallmarks of ageing, including the transcriptome, epigenome, functional protein expression, and cell migration speed. Intriguingly, it was also found that 13 days of reprogramming was the ?sweet spot? and longer time periods diminished the extent of transcriptional and epigenetic rejuvenation.

In their method, Babraham researchers took fibroblasts from three middle-aged donors (aged 38, 53, and 53) and then reprogrammed their fibroblasts for different lengths of time (10, 13, 15, 17 days) using a ?reprogramming cassette? that encoded Oct4, Sox2, Klf4, c-Myc to ensure all four Yamanaka factors were expressed.

The mechanism behind their successful transient reprogramming is still not fully understood and there remain a great many challenges when it comes to therapeutic applications. Only around 25% of the cells were successfully reprogrammed and other hallmarks of ageing such as telomere attrition were unaffected. Therefore, it is perhaps too early to say that we have found the silver bullet to end ageing, but we may have taken one small step closer to finding the mythical Fountain of Youth.

The efficacy of the reprogramming was determined by measuring changes in the different molecular hallmarks of ageing through methods such as examining a variety of ageing ?clocks? as well as looking at restoration of function in individual cells.

Ageing ?clocks? distinguish biological age from chronological age and are important for identifying genetic and environmental factors that influence the ageing process. In this experiment, a BiT age clock was used to investigate rejuvenation in the transcriptome, whilst an epigenetic clock was used to find evidence of epigenetic rejuvenation. Results pointed to a 30 year quantitative rejuvination in both.

The function of these reprogrammed cells was also considered, as they should both appear and behave like young cells. For example, production of collagen is a major function of fibroblasts, so the expression of all collagen genes were examined before and after reprogramming. They found that collagen I and IV (proteins downregulated with age) were restored to youthful levels after transient reprogramming. Fibroblasts are also involved in wound healing responses by moving into areas that need repairing (we heal slower with age due to the reduction in the cell migration speed of ageing

The Fountain of Youth by Lucas Cranach

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Clash of the T itans: Spinosaur us vs T yr annosaur us Aiken L au A one minute fight in Jurassic Park III immortalised the clash between the Spinosaurus aegyptiacus and Tyrannosaurus rex. One of the only incidents in popular culture in which the King of the Dinosaurs was promptly dethroned. However, this fight, involving the Spinosaurus snapping the Rex?s neck with its forelimbs, is nowhere near the truth. With that aside, let?s dive into the facts behind this Cretaceous (NOT JURASSIC) clash.

shaped tail packed with muscle similar to a crocodile?s; this served as both a strong weapon to sweep potential targets off their feet, and an aid for aquatic locomotion (perfect for its home on the marshy coasts of Cretaceous Egypt).

This habitat was one of the most dangerous places to live in Earth?s history. The Spinosaurus coexisted with another large carnivore, Carcharodontosaurus (which was also bigger than the T. Rex). Although it seldom fought with Carcharodontosaurus as the latter mainly tackled larger prey (like other dinosaurs) on land. But, this does not mean they never clashed. They would encounter each other regularly in the dry season as Spinosaurus? aquatic hunting grounds dried up in the heat forcing it to hunt land animals. This suggests that the Spinosaurus, despite being specialised to eat fish, was more than capable of holding its ground against large dinosaurs. These confrontations often turned in the Spinosaurus? favour due to its large sail, which intimidated other opponents and won a skirmish without a single blow.

Our first contender, the Spinosaurus, lived around 90 million years ago and was a semi-aquatic predator. Its most impressive prey include the eight metre sawfish, Onchopristis. Spinosauruses could grow up to 17-18 metres long and exceed 7 tons in weight. It is the largest carnivorous dinosaur ever discovered. The giant sail on its back would most likely have been for intimidating rivals and thermoregulation. It also had long crocodilian jaws with conical teeth. Small pores at the ends of the snout would have been used for sensing vibrations in the water ? a great tool for seizing fish. Its viciously large claws on its muscular forelimbs were also adept at killing fish and land animals alike. Despite the movie dinosaur having a conical tail, the Spinosaurus was recently discovered to have had a broad, paddle

The Tyrannosaurus rex could not have been more different. This prehistoric tyrant lived in the Late Cretaceous period, 67-65 million years ago, preferring the comfort of dry land.

This 12 metre North American juggernaut was shorter than the Spinosaurus, but was the heaviest of all known carnivorous dinosaurs at around ten tons. A robustly built predator, the T. Rex had a broad head and neck, and serrated teeth as long as bananas.

The jaw packed a huge bite force of up to 6.5 tons, which is the strongest bite recorded for all land animals and could crush a car. This

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enabled it to harness ?puncture-pull feeding?, which involved the predator's biting deep into its prey, puncturing the insides. Strong neck muscles would then pull back the head and rip out a huge mouthful of flesh, bone, and organs to inflict critical damage, killing the unfortunate victim with shock and blood loss. This unique method of feeding was exclusive to the Tyrannosaurus and its family as it requires teeth rigidly attached to the jaw (otherwise all the teeth would be unceremoniously pulled off when the animal attempted it) and robust neck muscles to pull back the huge head while its teeth were embedded deep in the flesh. It developed this way of feeding to pierce the armour of large herbivores, like its equally iconic contemporaries Triceratops and Ankylosaurus. Notably, recent research has suggested that this predator hunted in family groups, not just the men, but the women and the children. For them hunting was a family excursion!

beneficial for either party.

So what would happen if these two prehistoric predators met?

To conclude, between these two reptilian behemoths, there is no clear winner. Each one had its own strengths and ecological niches, making the outcome of a potential fight heavily dependant on the location.

However, it should be noted that research into these apex predators is still ongoing and new discoveries may be made which could dramatically shift our understanding of either dinosaur. Who knows, perhaps newfound knowledge may shed light on the conflict of these two prehistoric beasts.

If coaxed to fight, the outcome would have been heavily dependant on the setting. On dry land, whilst the Spinosaurus had more experience in dealing with large carnivores like Carcharodontosaurus, it would find it harder to launch a surprise attack owing to its vast size and sail. The T. Rex would most likely reign victorious in this situation, taking advantage of its powerful jaws evolved to grip and tear large prey, while the Spinosaurus? jaws and claws were more suited for fish. However, in any remotely aquatic habitat, it would be a completely different story. The Spinosaurus was the undisputed king in the water, easily propelling itself in the water and detecting its rival?s location with the pores on its snout.

The T. Rex, would definitely be outmanoeuvred by its semiaquatic rival.

Funnily enough, the T. Rex would have been preoccupied trying not to drown, rather than focusing on the fight.

Short answer: They wouldn?t even fight.

In the first place, they would not have even come into contact as they lived on different continents 40 million years apart. Even if they had met, there would have been nothing to fight over, as they occupied different ecological niches and shared different forms of prey. At most, they would have displayed threats to each other (the Spinosaurus would probably have won this with its gargantuan size and intimidating sail), instead of going into a fully-fledged fight, which could have crippled, if not outright killed, both creatures. Remember, these creatures aren?t movie monsters, they are animals that aim to conserve energy. As such, aimless fighting would certainly not be

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Mendel's Discover ies in the Under standing of Complex Diseases Yuxi L iu With roughly 80% of all rare diseases resulting from genetics, 400 million people worldwide suffer from 7,000 distinct Mendelian disorders. However, the genetic basis for over half of these remains elusive.

Complex disease phenotypes are only partially represented by our genomic sequences; under the influence of external factors, such disorders arise from not only heredity, but environment, mutation, lifestyle and evolution ? it is the pathological confluence of Darwin and Mendel.

strand, and the exact number of repeats will determine the gene?s penetrance ? in most severe cases, repetition exceeds 41 codons.

Roughly 50% of affected parents? offspring will suffer from HD due to the presence of a dominant allele, as stated by Mendel?s principle of uniformity.

Although HD may purely be due to gene mutations, many disorders may be alleviated or exacerbated by lifestyle changes and environmental alterations.

Commonly known as ?Asian flush?, the accumulation of acetaldehyde causes dilation of facial blood vessels resulting in redness ? a condition present among approximately 40% of Asians.

Studies uncovered a mutation within the ADH1C gene that codes for the gamma-subunit in alcohol dehydrogenase (ADH), an enzyme which catalyzes the rate-determining step of ethanol metabolism. However, caucasians are less likely to inherit said deficiency owing to genomic differences caused by environmental factors. In the 18th century among most European countries, 2-3% alcohol was the main source of fluid intake due to lack of sanitary water. Over time, gene adaptations have thus led to more ADH production within these individuals.

Mendelian patterns of inheritance can be used to study the patterns of inheritance of single-gene disorders across a family pedigree. One such example being Huntington?s Disease (HD) ? individuals with a single mutant autosomal dominant huntingtin gene (HTT) are likely to suffer from HD in their late 30s, resulting in cognitive decline and involuntary movements caused by the ?triplet repeats? mutation. Extra repetitions of the codon ?CAG? are added to the polynucleotide

Nevertheless, discoveries regarding the genetic nature of illnesses offer minimal information about the genes themselves; phenotypic variability in disease severity occurs even amongst monozygotic twins with an identical primary mutant gene. As shown by Gaucher Disease (GD), its clinical classification can be categorized into type I

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(non-neuronopathic), type II (acute), and type III (sub-acute); the first of which, was found to be predisposed to Parkinson?s Disease (PD), whereas types II and III were characterized by neurological impairment.

Although the clear cause of PD is still unknown, it?s certain that the mutant GBA1 gene in GD is a prevalent genetic risk factor in the exemplification of PD. Detailed investigation of interactions between genes would certainly provide aspiration towards the complete understanding of complex polygenic diseases. Although projects such as the Encyclopedia of DNA Elements (ENCODE) and several genome-wide association studies (GWAS) have mapped out the entire human genome in an orderly fashion, the functions of non-coding introns within the double helix remain a mystery.

0.025% can be altered by our modern pharmacopeia. The presence and feasibility of gene-sequencing technology has led to a lasting war of personalized medicine against complex diseases. Recent success of clinical trials for Chimeric Antigen Receptors Cell Therapy (CAR-T) in the treatment of acute lymphoblastic leukemia is sure to act as a stepping-stone towards our ultimate victory in this battle. Regardless of the rarity of such diseases, we must increase our financial motive and further our research into the mechanisms behind genomic expression in order to stand a chance of curing life-threatening illnesses such as cancer.

To fully understand the variability of phenotypic expression in Mendelian disorders, it?s necessary to analyze the entire genomic information of affected individuals. The completion of the Human Genome Project in 2003 has revolutionised scientists?approach to complex diseases by providing new insights into navigating disease-causing mutations. An example being single nucleotide polymorphisms (SNP) ? single DNA base-pair changes used as genetic markers for assessing disease risk and associated mutations. When they occur in the functional region of a used protein, or in higher frequency in affected vs unaffected subjects, it may be an indication that SNPs are physically close to the disease-causing mutation. They may be seen as genetic signposts, or an internal GPS system for the genome.

Out of the several million biological molecules present in the human body, only

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Biotechnology Mycor emediation: H ow Fungi Can be Used to Clean the Wor ld Ynon Weiss As the world continues to industrialise and develop, environmental and health concerns over chemical waste are escalating.

Traditional physicochemical methods for waste treatment are often effective, but typically onerous to scale up, unsustainable, and frankly expensive.

polycyclic aromatic hydrocarbons (PAHs) ? a byproduct of fossil fuel combustion, waste incineration, and steel production. PAHs are known carcinogens and have also been linked to cardiovascular disease. Whilst bacterial degradation of PAHs is also a possibility, the extracellular nature of fungal enzymes means that they are able to diffuse towards the pollutant molecules in soil and thus the initial attack on the PAH molecule is more useful ? a feature not seen in bacteria. Additionally, microbial enzymatic activity is usually limited to low molecular weight PAHs, with higher molecular weight molecules being recalcitrant (resistant to decomposition). Yet, studies have shown that fungal enzymes have the capability to overcome this. As opposed to fungi, bacteria often use the pollutants for their own growth. This means that the efficiency of their degradation relies on the benefits reaped by the bacteria from the products. At low concentrations of pollutants, or if the molecules have a low energy content, the bacterial breakdown of the molecules is less efficient, and this presents a problem that can be solved by mycoremediation. Degradation pathways in bacteria are in general much more specific than fungal pathways, and this creates a difficulty for them to decompose large, complex molecules with high numbers of functional groups.

Bioremediation is the process by which organisms are used to break down environmental pollutants, often involving the use of bacteria, microalgae and plants.

Fungi, however, provide an interesting route for the detoxification of wastewater and soil, removing heavy metals, organic pollutants, pesticides, and many other toxic chemicals.

Several species of fungi, known as white-rot fungi, have the ability to decay wood as they secrete extracellular enzymes that break down lignin ? known as ligninolytic enzymes. Of course, wood is not the target pollutant needed to be removed, but lignin, a class of organic polymers, possesses a similar structure to many organic pollutants.

Laccases, a type of ligninolytic enzyme, are therefore also able to oxidise and break down a variety of other aromatic compounds in waste, such as azo dyes, bisphenol A, and several pharmaceuticals.

The low-specificity of many catabolic fungal enzymes is an attractive feature of mycoremediation, allowing many ligninolytic enzymes to act on other substrates such as

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So, should all bacterial cleaning methods be replaced with mycoremediation?

are able to take up the heavy metals and remove them from the ground by biosorption to their cell surfaces, where they then enter the mycelium passively. Yet fungi have applications beyond the environment. A study from the VTT Technical Research Centre of Finland reported an 80% recovery of gold from electronic waste using mycoremediation methods.

Not exactly. In fact, studies have shown that the presence of the mycelium in fungi allows for increased movement of bacteria in soil which has physical barriers such as air-filled pores. Fungi could therefore not only be used to degrade pollutants themselves, but also to stimulate bacterial breakdown.

Mycorrhiza is the mutual symbiotic relationship between fungi and plants, in particular between fungi and the roots. This often enhances the decontamination activities of the plants, aiding in the uptake of both nutrients and heavy metals.

Mycorrhizal fungi reduce the harmful effects of the pollutant molecules on plants, allowing them to continue to grow, while also providing the them with water and minerals.

In return, the plants supply the fungi with sugars produced by photosynthesis.

Organic pollutants are merely one type of chemical waste, with metals, particularly heavy metals, posing a significant threat to the environment. Metals such as cadmium, lead, nickel, and mercury are often generated through the mining of metal ores and electroplating, and again are associated with organ damage and carcinogenic effects.

Although complex organic compounds have the potential to be broken down into smaller molecules, metals, being elements, cannot be degraded further. Instead, they must be either transformed into less harmful species, or separated from any susceptible part of the organism ? such as by intracellular immobilisation. For example, some members of the Aspergillus genus are able to reduce Cr 6+ to Cr 3+, a much less toxic form. Fungi

Mycoremediation seems to be a sustainable and cheap method to clean up waste, with the fungi not only directly decontaminating the environment, but also increasing the capacity of both bacteria and plants to do the same, resulting in a healthier ecosystem.

L ipid Nanopar ticles: A New Er a of Vaccines T homas H allé The Covid-19 pandemic boosted interest in the biotechnology behind the various strategies used by scientists to halt the spread of the virus. One key reason we were able to return to our daily lives was the nationwide vaccination programme, and whilst there were a variety of different vaccine platforms used by pharmaceutical companies, Pfizer and Moderna were the first companies to bring a vaccine using a

nucleic acid platform to market. These rapid responses represent key progress in our ability to swiftly design and manufacture viral vaccines. Although this technology has been available for over four decades, in the past it was received with scepticism by scientists who were unsure of its ability to manifest into a viable vaccine. The reasons for this doube were twofold: mRNA has an incredibly delicate structure, and its strands 16

Liposomes have been engineered to avoid recognition (which prevents an immune response and so premature destruction) and to have increased specificity. Targeted liposomes are designed with surface-attached ligands to recognize and consequently bind to specific receptors present on the surface of cells. The liposome's membrane is very fluid, and so a dynamic organisation of targeting ligands is displayed. This allows for optimal binding to cell surface receptors. These targeted liposomes are generally prepared by conjugating small molecule ligands, peptides, or monoclonal antibodies to their surface.

Furthermore, liposomes have also been heavily engineered to prevent removal from the blood flow by phagocytes. To avoid

possess a negative charge, making it difficult for them to pass through the largely hydrophobic phospholipid membranes that surround cells. Scientists, however, were able to turn to a delivery technology, with origins older than the idea of mRNA therapy itself, in order to revolutionise the concept into a working vaccine delivery mechanism ? that technology was lipid nanoparticles.

The lipid nanoparticles currently used as a vehicle for the delivery of mRNA and other therapeutic agents have undergone years of development. They have been engineered to exhibit more complex internal architectures and enhance physical stability, both of which ultimately increase specificity. The earliest generation of lipid nanoparticles, liposomes, was discovered when scientists observed closed lipid bilayer vesicles forming spontaneously in water. These liposomes consist of one or several bilayers, which range in size from 20 nm to 100 nm, with smaller liposomes being preferable due to their increased chance of phagocytosis. Their structural properties meant they were immediately highlighted as potential drug delivery vehicles. This is because their hydrophilic aqueous interior, and hydrophobic hydrocarbon chain region in the bilayer, can carry both hydrophobic and hydrophilic drugs. On a simple level, to

detection, liposomes have been coated with biocompatible inert polymers, typically polyethylene glycol which attaches to the heads of lipids in the bilayer. This has given rise to a class of liposome known as the ?stealth liposomes?, as they are almost ?invisible?to cells of the immune system.

The latest successful use of lipid nanoparticles is in the delivery of mRNA in the context of Covid vaccines. These vaccines deliver mRNA encoding for the SARS-CoV-2 spike protein into the cytoplasm of host cells, where it is translated in the ribosomes into the spike protein, which thereby acts as an antigen to stimulate an

deliver the drug molecules to a site of action, the lipid bilayer fuses with the cell surface membrane of the target cell via endocytosis.

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immune response to the virus. Each nanoparticle used in the vaccines is approximately 80 nm to 100 nm in diameter, and contains approximately one hundred mRNA molecules each.

macropinocytosis or receptor mediated endocytosis.

Following cellular internalisation, LNP?s are trapped in endosomal compartments (essentially a lipid bubble), and consequently the endosome?s acidic interior protonates the heads of the ionizable lipids, making them positively charged. This positive charge triggers the LNP to undergo a conformational shape change, which helps it break free from the endosome and ultimately release the mRNA into the cell cytoplasm.

In essence, the LNPs used in the COVID-19 vaccines contain just four ingredients: ionizable lipids whose positive charges bind to the negatively charged backbone of mRNA, pegylated lipids that help stabilise the particle, and phospholipids, as well as cholesterol molecules that contribute to the particle?s structure. Thousands of these four components help to house the mRNA, shielding it from the enzymes and cells of the immune system, and translocating it to the cytoplasm of target cells, where it can finally be unloaded and used to code for the spike protein. Lipid nanoparticle technology has meant that mRNA vaccines, which reign supreme in the vaccine market for their rapid development and manufacturing, have been able to reach the market and thereby tackle Covid-19 containment. This technology provides a promising future for subsequent responses to viral pandemics.

The lipid nanoparticles (LNPs) used in both the Pfizer and the Moderna vaccines contain an ionisable lipid. This lipid is positively charged at low pH, allowing for RNA complexation, and is neutral at physiological pH, which reduces the potential toxic effects and facilitates payload release. The LNPs also contains a PEGylated lipid to reduce opsonization by serum proteins and clearance by phagocytes (as mentioned before, to prevent the destruction of the delivery vehicle by phagocytes prior to its reaching the target cell). The phospholipid distearoylphosphatidylcholine (DSPC) and cholesterol help to pack the mRNA into the lipid nanoparticles. Furthermore, the hydrocarbon chains found in the bilayer of the LNP are connected through biodegradable ester groups, allowing for their safe clearance after the mRNA reaches the cytoplasm of the target cell.

Once the lipid nanoparticles reach the target cells, they can be internalised by

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Book Reviews T he Emper or of All Maladies By Siddhar tha Mukher jee Yuxi L iu From injecting patients with folic acid to the modern immunotherapy technology, Mukherjee describes in depth the medical journey of humanity?s 4,000 year war against cancer. In particular, he pays ultimate respect to generations of doctors and researchers who have dedicated their entire lives to fighting this war.

The journey begins with the story of chemist Sidney Farber and his perseverance in finding the cure for acute lymphoblastic leukaemia. Working at a children?s hospital, he witnessed the unwavering pain and endless suffering of affected children, and the hopelessness of doctors (at the time there were no treatment options). Driven to end their agony, he worked as a public cancer research advocate and pioneered the first nationwide cancer fundraising campaign together with activist Mary Lasker. Unlike doctors at the time who used radical discectomy to ?slice? out the tumour, as an intelligent chemist, Farber turned to chemicals and discovered a novel cancer treatment ? now known as chemotherapy.

carbon soot in their lungs. This led to the term ?carcinogen? appearing in our dictionaries for the first time. In addition, as part of Farber?s research group, scientists Doll and Hill were first to discover the strong link between smoking and lung cancer. This was the inception of epidemiology (the study of populations to learn about disease).

In addition to chemical carcinogens, many viral carcinogens were also linked to cancer.

The most notable of those being the HPV virus, the culprit in 5% of total diagnosed cancers worldwide and roughly all cases of cervical cancer in women. ?Prevention is the best cure?, as Mukherjee states.

Mukherjee also highlights the vital role of statistical data analysis in medical research.

The first example being scientist Percival Pott, who noticed an unusual number of young chimney sweepers diagnosed with scrotal cancer in the 1980s, which was later discovered to be due to the accumulation of

So what are the treatments available?

Unfortunately as Mukherjee mentioned in ?The Gene?: out of the several million

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The presence and feasibility of gene-sequencing technology may prove to be the turning point in this war. The success of the drug ?Herceptin?in targeting ?Her-2? positive breast cancer patients is sure to act as a stepping-stone towards our ultimate victory. Regardless of prevalence, we must increase our financial motive and further our research into the mechanisms behind tumour growth if we hope to stand a chance of curing such life-threatening illnesses.

biological molecules present in the human body, only 0.025% can be altered by our modern pharmacopoeia. We are merely starting to comprehend the entirety of the human anatomy, and as such our treatments are limited. The big challenge of cancer treatment has always been finding a suitable target site which exclusively suppresses the growth of cancer cells. Nevertheless, it also means that if a specific gene mutation can be identified and linked to a type of cancer, targeted treatments can be developed.

A Br ief H istor y of T ime By Stephen H awking H ar uki Matsunaga The book published in 1988 by one of the most brilliant theoretical physicists in history had in the first ten years of its release already formed a monumental landmark for science. Ranging from profound discussions about the origins of the universe to detailed insights of elementary particles, Hawking shares, along with his offbeat humour, a brief history of time. In this book review, I will go into further detail into the chapter which I found the most fascinating: chapter four on The Uncertainty Principle.

know the past, surely we can accurately predict the future.

Hawking begins by describing the views of French astronomer and polymath Pierre-Simon Laplace regarding the universe?s purely deterministic nature. In a book he wrote in 1819, Laplace asks the reader to imagine an omnipotent demon who knows everything about the universe, this being the exact positions and momentums of all particles in the universe at once. Pierre-Simon proposed that this demon would be able to predict anything in future by knowing everything from the past.

This was determinism in a nutshell. If we

kB = Boltzmann constant

The scientist then follows through this by commenting on another monumental scientific discovery, the formulation of the Rayleigh-Jeans law at the turn of the century. The law?s intended use was for calculating the energy intensity released from black bodies.

The formula states: B = spectral radiance

c = speed of light T = absolute temperature in Kelvin ? = frequency By using this, Hawking suggests the ridiculous conclusion that it entails if we base it on determinism. He explains that if we go by the law ?a hot body should radiate the same amount of energy in waves? with different frequencies (which we know is absurd), since frequency is unlimited, we could argue that infinite energy is radiated.

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The author then introduces us to Max Planck?s invention of quantum theory through his solution to the black body radiation issue. He proposed that energy emitted from electromagnetic waves can be quantised into packets of energy rather than being continuous. This would mean that, at certain high frequencies, the energy required to release a single quantum may be more than is available. Thus the rate of energy lost by black holes would be finite and not limitless.

? = Uncertainty of position of particle p = Uncertainty of momentum of particle

? = Planck?s constant Quantum mechanics is then introduced.

Hawking explains how Heisenberg, Erwin Schrödinger, and Paul Dirac reformulated quantum theory into what we now know today as quantum mechanics. In this theory, the position and the momentum of a particle was combined into one singular ?quantum state?.Quantum mechanics does not output a single result of a process but rather the likelihood of separate different results.

The theorist then discusses the most significant topic in the chapter, the uncertainty principle which was created by Werner Heisenburg in 1926. Heisenberg argued that finding the accurate position and momentum of a particle is impossible.

The German scientist believed that to find the future position and momentum of a particle, one must find its current values. To find these measurements, one shines light, quite literally, onto the particle. For the most accurate position of the particle to be found, the wavelength must be as low as possible.

However, by Planck?s quantum theory, we cannot use an arbitrary amount of light but a quantum. Although this would be ideal, this singular quantum will affect the momentum of the particle significantly and thus our measurements of the speed of the particle would be invalid. If we tried to measure the velocity of the particle, we would need to use light of a higher frequency. This would lead to a less accurate result for the position of the particle. Therefore, we cannot accurately find out the position and the momentum of an object at the same time. This famous dilemma is represented by this formula:

Stephen Hawking then concludes the chapter by explaining how quantum mechanics may still to greatly influence the scientific world and may even disprove some of the cornerstones of physics. It is even hinted by Hawking that quantum mechanics may reinforce the ?downfall?of Einstein's theory of general relativity.

Hawking?s ability to disseminate frighteningly difficult topics in a simple manner is what stood out to me. I was also attracted to the fact that for each analysis of a theorem or a principle, he always left some bits of knowledge out. I enjoyed figuring out the answers to these questions and I believe in this book, Hawking entices us to do so in a very skilled manner. Who would have known that a man without without the ability to talk could write such an eloquently shaped book?

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Chemistr y T he Catalytic Condenser ? a Chameleon Device Appr eciating the Value of Catalysts Teddy Onslow As the world moves away from fossil fuels in the modern pursuit of a green economy, we have become increasingly dependent on cleaner forms of renewable energy, such as solar and wind power. Green ammonia is capable of delivering clean power to more markets by capturing, storing, and shipping hydrogen for use in emission-free fuel cells and turbines. Having identified this great opportunity, chemical companies are developing a route to green ammonia in which hydrogen is produced by water electrolysis ? a method which can be powered by alternative energy ? rather than from the burning of hydrocarbons. This will make ammonia production virtually carbon dioxide-free. However, by estimates, the production of green ammonia costs between two and four times as much as conventional ammonia production, the cost of catalysts critical to its production accounting for a significant proportion of this heavy cost.

A team from the University of Minnesota has designed and produced a new instrument, the catalytic condenser, which is capable of fine-tuning cheaper and more abundant metals to behave like these hugely expensive metal catalysts by simply varying an applied voltage. This breakthrough in the chemical treatment of ordinary metals has the power to revolutionise the future of sustainability.

These changeable metals are often referred to as chameleon metals for their ability to metamorphose their surface chemistry into specially selective structures for the best performance. The catalytic condenser uses ultra-thin film strips of alumina and graphene, which both cost less than $225/kg.

Therefore, this device allows these metals to act as catalysts way above their paygrade.

Reactions where wind and solar power are taken to convert water into ammonia are Sabatier limited; the Sabatier Principle states that the interactions between the catalyst and the substrate should be ?just right?, that is neither too strong nor too weak. If the interaction is too weak, the molecule will fail to bind to the catalyst and no reaction will take place. On the other hand, if the interaction is too strong, the product fails to dissociate. This means that when looking at the rate of reaction we can plot different catalytic materials such that we see an optimum in performance. We already have materials that achieve this theoretical ?speed

Catalysts increase the rate of a reaction by enabling alternate pathways for the reaction with lower activation energies, all whilst remaining unused and unchanged. Metals such as platinum, palladium, and rhodium are catalysts used to manufacture important materials and chemicals in many industries.

Rhodium and Platinum alone cost more than $529,000/kg and $31,000/kg respectively.

Their rarity drives up manufacturing costs.

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limit?for chemical reactions, however, these reactions are still far too slow to be viable for technologies required to address problems such as climate change.

isopropanol to propene was used to investigate how altering the voltage affects the rate of reaction. In figure a (leftmost in bottom figure), the purple line shows an alumina material where positive bias (when holes are added/electrons are removed) of 3 V has been applied and the metal transforms.

This clearly indicates that the rate of the dehydration increases when a positive bias is applied, and also that the temperature corresponding to the peak rate of propene formation decreases. Therefore, as seen in figure c, the activation energy decreases when a positive bias is applied. When we further examine the surface chemistry at the active site (alumina), under positive bias, the bond length between aluminium and oxygen atoms decreases, and so they strengthen.

Thus, the binding energy increases as isopropanol binds more strongly to the alumina surface, resulting in lower activation energy for the reaction.

The device is composed of a layer of alumina (the solid acid site) on a layer of conductive graphene, which rests on top of an insulating layer of hafnium oxide, supported by a conductive silicon layer. When applying a voltage, electrons or holes (the removal of electrons) are added to the catalytic layer and perturb the performance of the material. This begs the question of how much charge should be added to the plate in order to reach optimal rate of reaction?

When a voltage was applied to the device and the charge uptake measured, it was experimentally found that there is almost an order of magnitude more charge uptake with alumina and graphene together, versus only graphene, allowing us to infer that charge can be imagined to seep into the alumina.

About 10% of an electron, on average, is emitted per active site on the alumina. A reaction involving the dehydration of

Considering Figure b, we see the rate of propene formation for +3 V Al 2O3 and neutral Al 2O3. These chameleon metals? ability to switch between these two states 1,000 times per second provides us with the unique ability to programme them by sending different electronic signals to tune the material to desired characteristics at different stages of the reaction. Consider a reaction where reactant A forms product B. A adsorbs and, under a strong positive bias, you can bind A very strongly and it will react to form B but then immediately put electrons

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back in so B can desorb. With the ability to change the surface chemistry of a catalyst over time, we are able to lower the energy of the transition state by applying a voltage, then flip to another state which gives very fast desorption from the catalyst. In fact, the instrument builds upon previous research from this Minnesota University team on catalytic resonance theory, which argues that by applying an external wave at the catalyst surface that resonates with the oscillations of binding energy and transition energy, a reaction can be drastically accelerated by carefully tuning the amplitude and frequency of the wave. By making the frequency of changes to the applied voltage equal to the frequency of

these oscillations, we are able to reach a resonant frequency that allows for reaction rates much higher than the theoretical maximum of catalysts (the Sabatier optimum). The amplitude also has a logarithmic impact on the enhancing catalytic rate.

The prospect of cheaper and tunable catalysts could be revolutionary in both storing renewable energy, as well as a variety of other projects, such as cheaply and effectively forming key components of bioplastics. This new development has a myriad of exciting possibilities in the future and will hopefully play an integral role in protecting our planet.

T he Chemistr y Behind Acne Alexis Andr onikos Acne is a common skin condition which disproportionately affects those going through puberty. The main symptoms are facial ?spots?, and hot and oily skin which may be painful to touch. Significant capital and time have been invested into improving treatments given it is such a vast and profitable market.

However, whilst treatments are available, we are yet to develop a cure.

to thrive, and cultivating sebum-producing toxins that damage the lining of the pore. A blocked pore initially turns red, as blood (white blood cells) rushes to the site of infection. Whiteheads form as a result of the accumulation of dead skin cells, pus, and dead white blood cells.

Acne products are quite divisive, however, the most effective ones tend to contain at least one of benzoyl peroxide, salicylic acid, alpha hydroxy acids or sulfur. Alpha hydroxy acids are a class of chemical compounds that consist of a carboxylic acid substituted with a hydroxyl group on the adjacent carbon.

These are believed to battle acne by removing the top layer of dead skin cells (which bacteria feed off), reducing levels of sebum production. Sulfur is believed to be effective as similarly it removes dead skin cells and absorbs excess sebum.

This skin condition is, in the most part, caused by a substance called sebum. Sebum is composed of triglycerides, wax esters, squalene, and small levels of cholesterol. It is produced by humans and its main purpose is to maintain soft skin and shiny hair; however, especially during teenage years, high levels of testosterone result in excess sebum production. This excess can clog up pores, allowing bacteria that feed off dead skin cells

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A beta hydroxy acid is an organic compound that contains a carboxylic acid functional group and a hydroxyl group separated by a carbon atom. Salicylic acid is a beta hydroxy acid often found in skin care products combating acne. It is lipophilic ? meaning it is able to dissolve in oils and fats ? which allows salicylic acid to penetrate skin layers and bind and destroy sebum. Furthermore, it also has anti-inflammatory effects. However, although research shows that salicylic acid is more effective than a placebo, it has not been proven to be extremely effective and can also cause irritation and dry skin (as can benzoyl peroxide). Salicylic acid is a naturally occurring compound which can be isolated from the bark of the willow tree. It can also be synthetically produced, either by biosynthesis of the amino acid phenylalanine, or from phenol. It is often produced using the Kolbe-Schmitt process shown below.

Naturally, salicylic acid and its derivatives are also found in fruits, particularly berries, and vegetables. Interestingly it is also often used in the synthesis of aspirin.

Benzoyl peroxide has a structural formula of (C6H 5?C(=O)O?)2. Upon application, it decomposes to form benzyl radicals and benzoic acid. Benzyl radicals kill bacteria, and benzoic acid unclogs pores which also contributes to the reduction of bacterial accumulation. Benzoyl peroxide is often synthesised in three steps. The first step is the Grignard synthesis of benzoic acid from bromobenzene. A Grignard reagent is a substance with a very polar carbon-magnesium bond in which the carbon has a partial negative charge and the magnesium has a partial positive charge.

This step is followed by the reaction of benzoic acid to form benzoyl chloride.

Finally, benzoyl chloride is reacted with hydrogen peroxide to form benzoyl peroxide as a final product. Alternatively, it can be produced by reacting benzoic anhydride with an alkali metal perborate in aqueous solution.

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Accutane (otherwise known as isotretinoin) is renowned as the most effective method of treating acne. However, the side-effects are more extreme and much more common. The list of common side effects includes dry skin, eyes, nose, and lips; irritation of the skin; sore mouth or throat; headaches; and muscle pains. The more serious side effects include unexplained bruising, dizziness, stomach pain, nausea, bloody diarrhoea, increased mental health problems and prolonged headaches. However, accutane is deemed to be very effective nonetheless.

Isotretinoin?s chemical structure is shown below. This structure can produce

preparation of isotretinoin (13-cis isomer of vitamin A acid). The reaction conditions are perfect for industrial scale production, and ensure a high quality product; levels of related isomeric impurities such as tretinoin (all trans retinoic acid) and 9,13-di-cis-retinoic acid are extremely low.

In conclusion, due to endless research in this field, there has been significant development of acne treatments. However, many are still sceptical of the effectiveness of these treatments, and many doctors believe that a healthy lifestyle and diet can be just as effective. Furthermore, many of these treatments display fairly unpleasant side effects as mentioned ? particularly with accutane, although it is currently deemed the best long-term solution to acne. Cost also presents a significant issue ? a 30 day supply costs over $200. In the future, with continued research, it is likely that more established treatments will be developed and become more accessible.

stereoisomers owing to the alkene groups on one of the side chains (with each carbon across the double bond bonded to two different groups). Its mechanism of action involves alterations in the cell cycle and apoptosis (programmed cell death). These actions reduce sebum production, preventing the blockage of pores and the growth of acne-producing bacteria. Shown below is an efficient process for the

T he Biochemistr y of Coffee Seb Elliot Coffee consists of 2-3% of caffeine and is responsible for most of coffee's known characteristics.

made of heterocyclic rings, which are cyclic compounds that have atoms of at least two different elements as members of its ring.

It has a chemical formula of C8H10N 4O2 and it is a methylxanthine, with its IUPAC name being 1,3,7 - trimethylxanthine.

The caffeine molecule, shown adjacent, is

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Caffeine is able to bind to adenosine receptors (a type of ribonucleotide similar to that of adenine and guanine) owing to the similarity in shape between caffeine and the adenine component of adenosine. Its structural similarity with adenosine, shown below, allows caffeine to act as a competitive inhibitor

fatigue, but also has anti-inflammatory effects. The anti-inflammatory effects of caffeine are due to the nonselective competitive inhibition of phosphodiesterases (PDEs). Inhibition of PDEs raises the intracellular concentration of cyclic AMP (cAMP), activates protein kinase A, and inhibits leukotriene synthesis, which leads to reduced inflammation and innate immunity.

To extract the caffeine molecule from coffee and tea plants, decaffeination needs to occur. This is when a carbon dioxide solvent is pumped into sealed vessels with the coffee beans, the caffeine dissolves into this solvent, and is in turn extracted.

The caffeine molecule is found naturally in the seeds of coffee plants and the leaves of tea plants. Within these plants, the caffeine molecule increases the rate of many biological processes, including photosynthesis, and water and nutrients absorption.

Upon consumption, caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding. Adenosine has multiple functions, most notably sleep promotion and maintenance. The underlying mechanism is centred upon the release of GABA (an inhibitory neurotransmitter), which inhibits neurons involved in wakefulness.

Consumption of caffeine also causes an increase in the oxygen supply by coronary vasodilation, and decreases the consumption of oxygen by lowering the heart rate. This inhibition by caffeine therefore results in its known effects of increasing heart rate and ?concentration? through the lack of promotion of sleep.

Caffeine is not only known to decrease

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Computer Science T he I llusion of the T hir d Dimension and the T r opes of Moder n Fir st Per son Shooter s Geor ge Niedr inghaus Doom (1993) was released in 1993 by id Software for MS-DOS, and came to home consoles over the next few years. With a file size of only 2.39MB, it was difficult to fit a 3D game into that little space. In contrast, Doom Eternal, the latest instalment, takes up nearly 38 thousand times as much space, at an obscene 89GB. The original game used a technique called ?ray casting?, colloquially known as ?2.5D graphics? ? even though the levels themselves exist as 3D objects, the demons, projectiles, weapons and pickups were all two-dimensional sprites. The enemies in particular had eight versions of every stage of their animations, one for each major angle they could be seen from. This technique is used in some more modern games, such as the mainline Danganronpa games. In their case, however, that was an artistic choice rather than a compromise to ensure that the game could run properly.

Sidedefs have three textures, middle, upper, and lower. One-sided linedefs (solid walls) use only the middle texture, but two-sided linedefs (which are entrances between sectors) use the upper and middle to fill the gaps between sectors with different floor/ceiling heights (e.g. stairs). A two sided linedef could also be used to make something appear to float.

Doom utilises a system called binary space partitioning (BSP). The data for each level is generated beforehand. The level is split into a binary tree, with the root node representing the entire level, and each subsequent node is a specific area. Each branch of the tree splits the area into two smaller areas. The line segments from split linedefs are called ?segs?.

The lowest nodes are always convex polygons, that do not need to be split further, called subsectors ?SSECTORS?, with a list of associated segs. The levels are then rendered recursively, starting at the root node, and each time selecting the subnode closest to the camera, drawing subsectors when the algorithm reaches them.

The engine used in Doom, called ?id Tech 1?, is quite simple as would be expected for the time.

It considers things only two-dimensionally at first, with a height used during rendering. It has vertices (internally referred to as ?vertexes?), which are joined to form lines (?linedefs?), which can have one or two ?sidedefs?. Sidedefs are grouped together to form polygons (?sectors?), which represent subsections of the overall level.

Sectors have a floor height, ceiling height, light level, and floor and ceiling textures.

All of the walls in the game are rendered vertically, which is why vertical camera movement is typically not possible. A stopgap solution called ?y-shearing? does exist, but causes a great deal of distortion at severe angles. The floors and ceilings (flats), however, are significantly less elegant. They

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are drawn using an algorithm similar to flood fill, so if the BSP data is built poorly, there can be ?holes? in which a flat bleeds into the edges of a screen. Flats are rendered as ?visplanes?, horizontal runs with a set height, light level and texture. Each x-position within the visplane has a set vertical line of texture. This limit can cause the need to split visplanes, such as where there are overlapping objects on a flat. This was an important limitation, as Doom had a limit of 127 visplanes, which could be reached with a 12x12 chessboard pattern. Visplanes are rendered alongside segs, extending towards the applicable vertical edge. As a result, the order in which rendering occurs is important so that closer visplanes cannot be ?cut off? by other visplanes meant to be behind them.

stored in the same column based format as the walls, but there is not the same guarantee that sprites will be rendered in the correct order. The sprites for enemies are selected based on what action the enemy is performing (attacking, moving, etc.), as well as what direction they are viewed from. Each individual enemy has eight versions of every stage of every animation. Doom and Doom II both used the same engine, but Doom 64, released on the Nintendo 64 used an improved version. 64 had 3D maps, and to a very limited extent, platforming. The ?platforming? was mostly using the sprint to make it across small gaps, but it was an important improvement that the first two games could not have handled.

To conclude, while the was an interesting game engine, it didn?t have much longevity.

Similarly to comic sans, it worked well given the restrictions of the time, but it can?t take advantage of modern computing power as well as 3D graphics can.

Finally, things, or sprites. Each sector has a linked list of sprites stored within. These are then drawn if they are within the player?s field of view. The edges of sprites are clipped if they are behind previously rendered walls, which is aided by the fact that sprites are

H ow does a Bayesian Neur al Networ k Model Differ fr om a T r aditional Point-Estimate Neur al Networ k?

Victor Shao and Roman L ipko A neural network is a computer system designed to mimic the workings of the human brain. It consists of the input layer, the hidden layer, and the output layer, all of which contain interconnected processing nodes, or neurons, that can learn to recognize patterns of input data. Each node can be thought of as a function represented by a set of weights and activation inputs that can either amplify or reduce the specific

input to be passed on to the next layer. The weights and activations form the input function, which is usually altered by a node-specific bias value. This is then transformed by an activation function, for example, a sigmoid function which produces an output between 0 and 1, and is thus easier to be passed through.

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The way the neural network learns is by adjusting the weights and biases of each individual node so the final output matches the desired result. This is done by representing the desired output as ?Vector A?, grouping the actual layer?s result as ?Vector B?, then finding the cost function which is represented by the difference between ?Vector A?and ?Vector B?. This cost function is usually computed cycle by cycle until it reaches convergence, which means the error between the predicted output and the actual output is close to 0 (although it could run an infinite number of times to train data).

The main difference between a PENN and BNN is how each node is represented; in a PENN, the node is described as a single value, whereas in a BNN it is expressed as a probabilistic distribution.

A BNN is used to estimate the underlying probability distribution of a given input. For example, with reference to the below figure, instead of a single value, the weights of each node are computed by a normal Distribution.

Differences bet ween a Bayesian Neural Net work (BNN) and a Point -Est imat e Neural Net work (PENN)

Furthermore, different BNNs work in different ways. Some may have the final output as a probability distribution, whilst some may only do so for the node functions (e.g. weights and biases). This is in contrast to traditional point-estimate neural networks which simply output the most likely estimate.

Below are some of the main advantages of BNNs. Firstly, they are more robust to overfitting ? the problem of being excessively trained so that it only responds to a narrow range of inputs ? by addressing regularisation properties (innate nature via probability distributions). In addition, since BNNs account for uncertainty in the data, they are useful in making predictions.

However, a Bayesian approach is more computationally expensive since each time the network makes a prediction, it must update its beliefs about the model parameters given the new data. This means it?s hard to scale to larger problems and is relegated to more specific questions such as in molecular biology. and medical diagnosis.

BNN (t op), PENN (bot t om )

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T he T r avelling Salesman Pr oblem Victor Shao and Roman L ipko essentially techniques or algorithms used to produce solutions which may not be optimal, but are efficient in the given time. A heuristic function creates a cost (a value generated from the function) to evaluate the accuracy of the current solution. Its purpose is to decrease this cost, to increase the accuracy of the solution to the optimal one.

For years, computer scientists have created optimization algorithms for perplexing and versatile problems, of which the Travelling Salesman Problem (TSP) has been a benchmark for many optimization methods.

The problem goes as follows: ?Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?"

Exact algorithms often take a very long time to execute. There are relatively fast techniques to compute an exact algorithm, such as the Held-Karp algorithm, which is an application of dynamic programming. It defines a set S for the cities which the route has to go through before reaching its destination, d. It starts with |S|=0 and gradually increases |S|, computing the smallest distance for each combination of size |S|. The smallest distance through S is broken up into the minimum value between going from some city 'c' in S to the new destination while going through the rest of the cities in S. However, the smallest distance to 'c' while going through the other cities has already been computed before in the set of |S|-1, so it is easier to compute the new possible distances. Although this is faster than a naive approach, it still has to take into account a considerable number of possibilities, thus resulting in a time complexity of O(n22n).

The image above gives an example of a solution to a problem. Here, the dots represent the cities and the line connecting them is the optimal solution.

It is considered to be a ?non-deterministic polynomial (NP) time hard? problem ? in simple terms, it is both hard to solve and verify, and more technically it can be transformed into another NP problem. To give a more intuitive understanding, the maximum number of paths possible in a naive solution (a brute force approach of trying all combinations) for 5 cities is 12 paths. For 10, it is 181,440 and for 20 cities, it increases to 6.082 × 1016!

However, due to intensive studying since 1930, there are a range of approximate and exact algorithms to solve this problem exactly to 10s of 1,000s of cities and approximate to millions. The majority of these algorithms use heuristics, which are

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As shown, exact algorithms get very computationally expensive as the number of cities increases, which was why approximate algorithms were devised.

One simple yet inefficient heuristic algorithm is the nearest neighbour algorithm, which is a type of greedy algorithm. In this algorithm, the salesman always chooses the nearest unvisited city as his next move. It constructs a tour very quickly but relies heavily on the positions of the cities and may sometimes produce the worst case. Thus, techniques, such as the pairwise exchange, exist. This removes n edges (where n is a pre-specified integer) and replaces these with n different edges that reconnect the fragments into a new and shorter tour.

An illustration of Ant Colony Optimisation

These algorithms are very basic examples of some sub-optimal ways to compute an approximate solution and there are many more, such as the Christofides algorithm, which was omitted from this article owing to the necessity of explaining graph theory extensively.

As explained earlier, this problem appears as a sub-problem in many areas, from order-picking in warehouses to drawing pictures. A famous example of a picture generated by the TSP is one by Robert Bosch, created in February 2009, of the Mona Lisa using a TSP problem of 100,000 cities. It was optimised by Yuichi Nagata in March 2009 to 5,757,074 bounds and there is a $1,000 prize to anyone who beats this record, hosted by the ?TSP Art website and the University of Waterloo?. So if anyone is interested, have a crack at this problem!

The third and final algorithm explained here is the Ant Colony Optimization, which uses a simulation of the Ant Colony System (ACS), a type of swarm intelligence method. It imitates real ants which lay down pheromones directing each other to resources. This algorithm sends out a large number of so-called ?ant agents? to explore many possible routes on the map. They travel through the graph based on heuristics from the starting point and ?pheromones?.

These pheromones are values added to the edges of the graph, increased by ants moving on the edge, to increase the likelihood of an ant travelling through that route. Once it reaches the end of the tour, it deposits more pheromones around the completed tour it has taken. From this, the later simulation iterations of ants will locate better solutions on average and at the end, the route with the most deposited pheromones would be a very close approximation to the shortest path.

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Engineer ing ?EJECT ! EJECT !?

Suleyman Ansar i fundamental processes are still in many ways similar to those initially introduced by Dragomir. When the pilot pulls the ejection lever, the canopy of the jet is jettisoned away from the aircraft by rocket thrusters before the pilot follows shortly after. This entire process takes less than a second! However, given the wide operating window of a fighter aircraft, speed and altitude can vary massively. As a result, a pitot tube configures the ejection based on the altitude and speed of the aircraft to ensure maximum safety.

For example, at an altitude of 50,000 feet (far above where a human can breathe), emphasis is placed on getting the pilot down to a breathable altitude as fast as possible so the parachute remains shut until this position. However, at lower altitudes, the parachute must open immediately in order to quickly slow the pilot down for a landing.

Inspired by the recent release of Top Gun: Maverick, I was fascinated by the way ejection seats work, their remarkable success record (they have saved over 7,000 lives), their reliability, and their design. So how does this amazing system work?

Since the inception of functioning aircrafts, some sort of escape mechanism has been present. During the early days of flight, when aircraft didn?t have canopies, the pilot could just bail out on their own by jumping from the aircraft with a parachute. However, this was not preferred by the Royal Flying Corps (the predecessor to the RAF) since it could incentivise cowardice during a combat situation in the First World War. As aircrafts became faster and more powerful, this original method of egress was no longer possible owing to g-forces and airflow situations. This became especially relevant when fighter jets started to travel at supersonic speeds. As a result, new escape methods needed to be designed. This led to the current basis of the ejection seat as we know it, which was initially developed by Anastase Dragomir in the 1920s. However, understandably, it was only during the Second World War that innovation really took off. Today, world leaders in the field such as SAAB and Martin-Baker continue to work at the cutting edge of technology to make ejection even safer and more effective.

Given that ejection seats are often the difference between life and death, it is important to consider the elements that make them so reliable. Since the 1940s, the success rate of ejection has increased from around 50% to over 90%, clearly demonstrating increased reliability. A single bolt can cost upwards of $100 due to its high specification; it must be manufactured with utmost precision and from the best quality materials, as well as being extensively tested before use. Similarly, redundancy is incorporated into the design to ensure that the seat works reliably even if one part fails.

The modern-day ejection seat is an extremely complicated system, yet the 33

However, state-of-the-art escape systems aren?t exclusive to fighter jets. Commercial aircrafts feature similar systems. Evacuation slides utilise compressed air to inflate them quickly. Safety is of paramount importance in aviation and companies are constantly

aiming to improve this situation. Recently, firms have placed greater focus on helping pilots survive the violent g-forces during ejection with new developments focused on improving neck projection.

T he Futur e of the Factor y Victor L iu Factories have a key role in human society ? we may not always be aware of it, but the vast majority of our products started life in a factory of some sort. In 1771 Richard Arkwright opened Cromford Mill, a cotton mill regarded as the origin for modern factories. It housed yarn making machines that were powered by water wheels, and was initially home to 200 workers. Its efficiency was far superior to existing cottage industries.

reliable, one of their major weaknesses is an inability to adapt to unexpected conditions, as they are simply following a fixed program.

In the future, control systems will have increasing amounts of integration with servers in the ?cloud?: communication with headquarters will bring extra intelligence to the production process. This brings new problems of cybersecurity; current best practice is to connect controllers to the factory?s internal network only. Any industrial systems exposed to the internet are at risk of attack.

Careful security-conscious engineering will need to be applied to minimise these risks to expensive production hardware, and control will likely remain on-site to minimise disruption in case of internet outages.

Since then, the industrial technology within factories has advanced rapidly. Many common elements of today?s factories are likely to persist, but new technologies are also changing the ways of mass production.

The days of production lines bustling with workers are drawing to a close; automation is becoming increasingly pervasive as older technologies are phased out.

The most common control loop used in such logic controllers today is the Proportional-Integral-Derivative algorithm, or PID for short. In simple terms, the PID controller bases its correctional action on three things: how far the current value is from the setpoint (the error), the cumulative error that has persisted (calculated by integrating the error), and how fast the error is changing (the derivative of the error). The proportional term makes the change proportional to the error, the integral term makes the change more extreme the longer the error persists, and the derivative term

Nowadays, most control systems in factories are based on Programmable Logic Controllers, or PLCs. At their core, they are microcontrollers that have input/output pins connected to terminals that can control various light loads such as contactors or lamps. However, they differ from a consumer-grade microcontroller module in their design, as they must be robust enough to withstand the electrical noise, vibration, and other abuse of a factory environment.

Although these controllers have proven 34

prevents overshooting of the target value.

Each term is weighted so that the controller can be ?tuned?to achieve the most control.

hardware, so that the system can still operate (albeit at a reduced capacity) if any sensor develops a fault. Redundancy (the incorporation of backup systems) can be used to alleviate this issue, but increasing the number of devices adds possible points of failure ? counterintuitively, this can actually decrease the reliability of the system!

As general computing technology advances, we can expect to see increases in the processing power of these logic controllers too. Although a PID controller or sensor monitor doesn?t require much processing power, recent technologies may need more.

A control system of the future will likely be able to visually survey the factory and react to potential snags in real-time, instead of relying on an external server to do the processing. This practice of processing data near its source is called edge computing.

Potentially revolutionary ideas and technologies are not limited to automation. ?Batch Size One? is a completely different manufacturing paradigm, whereby products are tailor made to each customer's specifications. This is possible due to better algorithms that can generate designs based on templates, and contrives the traditional approach of mass production to leverage economies of scale. When fully optimised, a batch size one factory can achieve similar profit margins to a traditional one.

Machine learning and AI based on edge computing have many newfound applications in the industrial space. For example, computer vision algorithms can detect stray objects on a conveyor belt (anomaly detection), or let a robotic arm pick up objects in varying positions. Many tasks that are currently performed by humans such as quality control will probably be replaced by digital eyes that can work faster and for more hours. With machine learning, a control system could automatically tune its parameters to fit a certain process; this would remove the main disadvantage of setting up existing algorithms, which is often a matter of trial and error.

The technology in factories tends to advance step by step, as each new concept is tried and tested. Current ideas are showing the potential to revolutionise how factories work once again. One day, in the not-so-distant future, we may find ourselves using things never before touched by human hands.

A risk of introducing ever larger numbers of increasingly complex sensors is reliability. In a factory?s high productivity environment, reliability is key; a single day of downtime can disrupt entire supply chains, especially with the prevalence of today?s just-in-time supply chains. This is a reason for the delay between a technology?s availability and its integration into factories. Any extra processing power will likely be installed as a coprocessor, an augmentation of proven

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Envir onmental Science Constr ucting a 'Simple' Climate Model Fr eder ick Dehmel In this article we will construct a simple model to calculate the temperature of the Earth in equilibrium.

Using the aforementioned Stefan Boltzman equation, we can calculate the power the Sun emits.

In order to better understand this model, consider the following three laws of physics.

Since the surface area of a sphere is 4?r2, and as we know the radius and surface temperature of the sun, we can create the following equation:

Firstly, power is an expression for the amount of energy transmitted in a given amount of time.

which after plugging in the values for the Sun?s radius (696,340 km) and surface temperature (5,778 K) gives us a final value for the power emitted by the Sun of:

The second law of physics that will often be referenced relates to intensity, which refers to the amount of power per unit area.

Finally, the power an object emits is proportional to the temperature of that object to the fourth power, times the area of that object, multiplied by a constant epsilon (which denotes the emissivity of an object), multiplied by a constant sigma (known as the Stefan Boltzmann constant).

In turn, we can use this to find the intensity of the Sun, as Intensity = Power/ surface area of the Sun:

Giving us an intensity of 1360 , which will be referred to as the solar constant, S. Now that the Sun?s power and intensity has been calculated, we have to analyse how the Sun?s energy interacts with the Earth. When solar radiation hits the Earth, it is effectively a flat line, and if we were able to view it in 3 dimensions, we would see a flat disc crash into the Earth and wrap around the globe.

This would mean that power from the Sun is conserved. In this context, this means that power in is equal to power absorbed, denoted as Pin = Pabs. Pin can be written as the solar constant times the area of the disc, and we can write P absorbed as the surface area of the Earth times some unknown intensity that is received by the Earth, which we were trying to find. We can also substitute ?r2 for

It is worth noting that the third rule only applies for black bodies (objects that absorb all wavelengths of light). For this article, we will assume that the Earth is a black body, meaning its emissivity is equal to 1.

By considering the relationship between the Sun and the Earth, as well as the physical attributes of both these bodies, we can begin to construct a model. The Sun is 150 million km away from the Earth, and emits energy in the form of heat and radiation, which travelling at the speed of light reaches the Earth 8 minutes and 20 seconds later.

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the area of the disc, and 4?r2 for the surface area of the sphere:

proved that I equal Sover 4, we can make one final substitution:

By doing so we can clean up the equation, as both radii refer to the radius of the Earth, allowing us to set the solar constant as 4 times the solar intensity received by the Earth: Rearranging this leaves received equal to 340 :

the

With a little algebra, we are given an equation that can find global temperature:

intensity

To test if our model works, we can try plugging in the values for the albedo and the solar constant, giving us a value of 255 K, or -18 °C:

Yet not all intensity received is absorbed; a proportion of it is reflected back into space due to the phenomenon of the albedo effect.

This is where we introduce the albedo constant, alpha, which is just a measure of the reflectivity of an object. The Earth's albedo constant is around 0.3, meaning 30% of the energy, and hence power and intensity, that the Earth receives is reflected.

One crucial element that we have failed to account for is the greenhouse effect.

To understand how the greenhouse effect alters our calculations, we first have to understand what emissivity is; emissivity is a measure of how effective an object is at emitting energy in the form of thermal radiation. While the Earth may (almost) be a black body, and hence should have an emissivity of 1, the atmosphere is not. The Earth may emit 100% of the energy it absorbs back out into space, but it first has to pass through the atmosphere. It is worth noting that greenhouse gases have an effect only on thermal radiation leaving the Earth.

In a nutshell, this is because thermal radiation enters the atmosphere as shortwave radiation and leaves as longwave radiation, and greenhouse gases are significantly more effective at trapping and remitting the latter. This attribute results in the atmosphere having an emissivity of around 0.612. If we retool our model in respect to this revelation, we are left with:

Thus the intensity the Earth truly feels is 0.7 times the intensity received, or about 238 watts per m2:

Now that we have have found a value for the intensity that the Earth has received, we will apply the Stefan Boltzmann equation once more.

Since power equals intensity times some unit area, we can construct the following equation: Since both areas represent the surface area of the Earth, we can simplify our equation down to I absorbed = Stefan Boltzmann constant, times by the emissivity, times by the surface temperature to the fourth power:

To help us, we can rewrite I absorbed as I received multiplied by the proportion of energy that is absorbed, and as earlier we 37

Mathematics Catalan Number s Sasha Gor in Delmas Imagine you invite 11 people to your birthday party and you all sit around a circular table. You want to greet your 11 friends with a handshake and they want to greet each other, however you do not want to cross arms with anyone and cause a mess.

In how many ways can you do this? In other words, in how many ways can 12 people, sitting around a circular table, shake hands without crossing over each other.

In the diagram above, person1 is at the bottom of the circle, a line represents a handshake and an a denotes the number of non-crossing handshake possibilities for n people around the circle. Each of the different people that person1 can shake hands with is drawn above. Notice how the question repeats itself: a12 = a10 + a2a8 + a4a6 + a6a4 + a8a2 + a1

One way of attacking this problem is by considering a specific person: person1. To ensure no one crosses over each other, and that when person1 shakes hands with someone, those in between them can all shake hands, there must be an even number of people between them. Person1 can also shake hands with those directly adjacent to them. Thus, if we number each person in ascending order clockwise from person1, they can shake hands only with persons 2, 4, 6, 8, 10 or 12. We can imagine person1?s handshake as splitting up the table into 2 further groups. This means that for each of person1?s possible handshakes, the question breaks down into the same question but for a smaller number of people. Let?s try to visualise this: Therefore, to answer this question we must look at how many ways people 10, 8, 6, 4, and 2 can shake hands without crossing over. We can do this by repeating the same process.

We can figure out a4 pretty easily by just

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considering four people and so there are only 2 ways: person1 can shake hands with the person on his left or right. Therefore a4=2. As a result:

But there is something hidden behind this problem: the numbers a2, a4, a6 ... are actually part of a sequence called the Catalan numbers. The Catalan numbers are a sequence which frequently surfaces in counting problems. How many ways are there of drawing triangles in a regular n-sided polygon shape? How many ways are there of getting to the point (n,n) by starting at the origin and only being able to move north or east without crossing the line y=x?

How many ways are there of creating a ?mountain range? with n up-strokes and n-down strokes whilst always staying above the horizontal line? And, how many ways are there for n people (where n is even) to shake hands without their arms crossing? It turns out the answer to all these questions are just the Catalan numbers.

Thus, there are 132 ways that 12 people can shake hands without crossing arms.

A Combinator ial Pr oof of Wilson?s T heor em Gabr iel T r enner man Have you ever tried to draw as many shapes as possible, from a given point, without taking your pen off the paper? Well, it turns out that this idea can be used to prove Wilson?s Theorem (which is quite complex!) without any prior knowledge of modular arithmetic or number theory. It provides a purely combinatorial proof to a number theoretic problem which I find fascinating. I hope to give you a good grasp of the proof by the end of the article.

This effectively says that (p - 1)! + 1 is divisible by p. Therefore, if we we show that is an integer , we will be done.

Let us reconsider the question I posed at the start, but this time let us more strictly define some parameters. Formally, we will consider p (an odd prime) points evenly spaced around a circle ? and count the number of polygons we can form by joining these p points in a single pen stroke. Such a polygon is known as a stellated p-gon. Note that you must also return to your starting point at the end.

First of all, what is Wilson?s Theorem?

Formally, W ilson?s Theorem st at es t hat for an odd prime p, (p ? 1)! ? ? 1(mod p)

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Why is this the case? Let us consider the 5-gon again. If you list the points that you reach in order (you must return back to the starting point, but we can ignore it) you will have six points in total, such as in the example below. These first five points can be in any order so there are 5! ways to arrange them. However, notice that for a particular sequence starting at any of the 5 points, the same shape is produced. For example, P1.P3.P2.P4.P5.(P1) and P4.P5.P1.P3.P2.(P4).

Also, notice that even if you start at the same point, two sequences will produce identical shapes ? one which goes anticlockwise (P1.P5.P4.P2.P3.(P1)) and one which goes clockwise (P1.P3.P2.P4.P5.(P1)). If we extend this logic to a general p-gon then it is intuitively true that the number of p-gons you can draw in general is just p! divided by two and p.

Firstly, it will be helpful to try a smaller case with a 5-gon and count how many exist.

Recognise that there are two types of p-gons: ?regular? and ?irregular?. A regular p-gon is one that has rotational symmetry of order p like that in ? and ? . An irregular p-gon is one that has rotational symmetry order 1 like that in ? and ? . Notice that because p is prime, we cannot have rotational symmetry of any order other than 1 or p. One might then ask how many of the p-gons are regular?

It turns out that this is the last step we need to finish our problem!

Notice that in the first two cases (red), the shape has rotational symmetry (the shape looks the same no matter how it is rotated) order five, so there is only one of each type.

In the other two cases (green), the shape has rotational symmetry order one so there are five of each type.

In fact, in general there are p-gons you can form for a given set of p points. We can quickly verify this as we found twelve 5-gons which is just .

If you look closely at the regular 5-gons, then you might notice that each line ?jumps? the

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by 13 .

2. (Balkan MO 2016) Find all monic polynomials f with integer coefficients satisfying the following condition: There exists a positive integer N such that for every prime p >nN, p divides 2(f(p))! + 1.

same number of vertices each time. In ? , each line connects two adjacent vertices (a clockwise jump of one) whereas in ? each line ?jumps two? (e.g connecting P1 to P3).

You might then ask why there are not more than two regular 5-gons? Why are there no cases of jumps of three and four? This is because a jump of three is equivalent to an anticlockwise jump of two and similarly a four is equivalent to an anticlockwise jump of one (as both take P1 to P2): they produce identical shapes. Extending this idea to the general p number of points case, then you will notice that we have jumps of the size from 1 to . As each size of jump gives a unique p-gon, we thus have regular p-gons!

This

means that all the remaining polygons must be irregular! This can be simplified to . But because irregular polygons have rotational symmetry order one, then this means that each type of irregular p-gon must contribute p separate p-gons. As there are a whole number of types of irregular p-gons, then it must mean that divided by p is a whole number. Therefore, is divisible by p which is what we wanted and so we are done. We have proved Wilson?s Theorem!

Wilson?s Theorem is often used in some Olympiad style problems. Here are some that you might find interesting: 1. (ARML 2002) Let be an integer such that Find the remainder when a is divided

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Medicine T he Futur e of Ar tificial I ntelligence in Medicine Zak Far azi The hybridization of our lives with Artificial Intelligence (AI) seems inescapable. Whilst some fear this is owing to the negative depictions in media and a general lack of understanding, others see opportunity. In fact, AI is already making its presence felt in the medical industry.

well-trained radiologist, and excited about a future where radiologists are supported by world-class AI and machine learning?.

In recent headlines, a genetically modified pig?s heart was transplanted into a human for the first time. How was this done? The company that made the heart, Revivicor, did so by knocking out specific ?pig?genes which result in the heart being assailed by the immune system, and replacing them with human ones. These genes promote the accommodation of the modified pig?s heart in the human body. This was done using the CRISPR genome editor, which uses special RNAs (crRNAs) to find a specific matching sequence of DNA. The discovery that the pig heart can be made compatible with a human is the first step in alleviating massive organ shortages, potentially saving countless lives.

But what if we could create individually tailored tissues or organs from scratch? This is a growing field known as regenerative medicine. Stem cells can differentiate to form almost any specialised cell ? so they would be able to differentiate into cardiac muscle cells which could form functioning heart tissue.

On the other hand, ethical issues must be taken into account. Most notable of these is ?componentation?, which could potentially lead to scientists' deciding to alter the human body. This goes against traditional human values and is potentially unethical.

Firstly, what is Artificial Intelligence?

Artificial Intelligence is a superordinate term for computers that are able to carry out so-called 'human' tasks which normally employ the use of reasoning, perception, and self-learning. So how is AI currently being used in medicine? The ability to find and identify minute details accurately, efficiently, and quickly is invaluable to those in radiology. For example, a deep learning model (a type of artificial intelligence that uses models inspired by the brain?s neurons) was created to aid the identification of lesions in breasts. The model was tested on data from eight hospitals: 90.7% of the MRI scans with lesions were considered to be abnormal by the AI and 40% of the scans without lesions were dismissed. This shows that AI can be used to significantly reduce the workload of doctors, giving them time to focus on other areas. This also has potential to improve productivity and reduce the likelihood of errors due to fatigue. AI could be revolutionary, to such an extent that a radiologist?s job at the American College of Radiology had two main criteria: the applicant ?must be an enthusiastic,

Now, the question is, how does AI come into this? Deep learning algorithms can be used to

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predict the behaviour of a cell in different conditions. By extension, it can be used to quickly and accurately predict what the cell will do in human environments ? critical information for researchers. According to Masayo Takahashi at the RIKEN Centre for Developmental Biology, through deep learning AI robots will have the ability to emulate skilled researchers in the regenerative medicine industry.

beings and there are boundaries around what it can be used for.

Another shortcoming of AI is its general usability. Most AI models are built using complex mathematical models and code. The average medic will not be able to easily understand or implement these models unless they undergo training, which may have cost implications especially for state run enterprises such as the NHS. On account of this, the general accessibility to AI training should be made easier and more cost-effective.

However, AI is not without limitations.

Firstly, the process of training an artificial intelligence model requires data to be collected and inputted to the program by a human being. The risk is there could be bias in these models, as data collected may not be random. In addition to this, data must be pre-processed before it can be used to train the AI. Hence, just as there is a regulatory body that approves which drugs and foods are released to the public, regulatory oversight which specifically assesses the use of AI in the medical sector is absolutely imperative. This would help ensure that AI is not susceptible to the same biases as human

In conclusion, AI looks to be an incredibly useful resource that will, in years to come, likely play a significant role in healthcare.

This has already been demonstrated by Moderna, who used AI algorithms to streamline the production process of the COVID-19 vaccine, which partly contributed to its rapid production. Though an effective regulatory framework would be needed to overcome the challenges that exist.

A L ife for a L ife: Xenotr ansplantation Oliver Milr oy-Goulding Since the time of the ancient Greeks, humans have dreamt of replacing human body parts with those of animals. Whilst science fiction writers have imagined cyborgs and metal hearts, scientists have chosen a less climactic method to tackle the more than 100,000 Britons on the transplant waiting list: pigs. seventeen people die every day in the UK while waiting for an organ, and xenotransplantation provides a prompt and plentiful supply.

transplantation and is by no means a new concept. Since 2000, gene editing has become a tangible reality, with breakthroughs such as CRISPR leading to the multi-gene editing, immunosuppressing, groundbreaking transplants of today. Recent examples include a pig heart put in David Bennett Sr, and a heart put in a non-human primate (NHP) . ?Life imitates art,?as Oscar Wilde said, and, in this case, there are startling similarities between it and Malorie Blackman?s 1997 book Pig-Heart Boy.

Xenotransplantation literally means ?foreign?

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In the last 20 years, much research has been done into preventing the rejection of xenotransplants in NHPs. Recently that research has moved into humans too. Just in 2021 we saw a braindead patient receive a pig kidney, and the aforementioned pig heart transplant. 2003 saw the first big leap when the Gal antigen (an identifying marker to our immune system) was knocked out of pig genomes. However, this was not without its tribulations; it took three years from cell work to birth. 2012 was a turning point, with the discovery of both CRISPR, and the publishing of the full pig genome, meaning it took only 150 days to create a multi-gene edited piglet. This has allowed scientists to prevent both humoral rejection (the attack of tissue by antibodies and the complement system) and coagulation dysregulation (abnormal clotting in organs) through gene-editing alone. Further combined with an immunosuppressive regimen of drugs and anti-inflammatory therapy, pig hearts have lasted over 900 days in NHPs, and corneas almost 400. Experiments have shown everything from the possibility of a cure for type one diabetes, to the xenotransplantation of pancreatic islets (clumps of insulin producing beta cells), to the reversal of effects of Parkinson?s disease by neuronal transplantation.

have shown no inclination of transmitting to NHPs in any studies, and can be edited using CRISPR. Porcine viruses have not been found to spread to immunocompetent humans, with the pigs being raised in a sterile environment to ensure safety. David Bennet Sr died because his pig heart was infected with a porcine virus, although there was no zoonotic transmission. The virus was limited to just the transplanted heart but went haywire because of a compromised human immune system and the absence of a pig immune system. This caused mass inflammation from day 40, and the patient died about 20 days later from catastrophic organ failure.

The potentials of xenotransplantation are enormous, but the ramifications are equally as serious. Public opinion needs to be considered, and researchers must bear in mind the wide variety of ethical concerns people have instead of just blindly improving the science for ?the greater good.?

Despite the many benefits of xenotransplantation, just because the donor is an animal does not mean life for a life transactions should be dismissed lightly.

Utilitarianism is often not compatible with major religions and the general population.

Zoonotic diseases must also be considered, and whether the general populace is prepared to take such a risk for the betterment of transplantation technology and the lives that it saves. Pig retroviruses

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H uman vs Disease Mustafa Sadeeq The ongoing battle between organisms and pathogens has been eventful to say the least.

History is dotted with horror stories of plagues and pandemics spreading through nations. However, due to scientific advances, the human population has rapidly increased over the last few centuries, with minimal impact from natural population-controlling diseases. But is it possible for disease to be eradicated as a whole?

advancements in medicine may lead to the elimination of disease and that the eradication of smallpox was the first of many to come.

On the other hand, there is a vast variety of diseases and, despite improvements in treatments and vaccines, it is unlikely that we will be able to exterminate all known human pathogens. Disease-causing organisms are constantly mutating with the aim of increasing their lifespan inside and outside of the body. The COVID-19 virus mutated several times over the course of two years, becoming increasingly transmissible. The method used to cope with the mutations is inefficient: each variant requires a different vaccine followed by several booster jabs which only provide immunity for six months.

This evidence implies that by attempting to reduce the spread of disease, humans will be left with more transmissible and potentially more dangerous variants. This ability to mutate rapidly gives pathogens a significant evolutionary advantage over humans, and for that reason diseases are something that humankind is forced to co-exist with.

Although we can inhibit the spread of illnesses, it is unlikely that we will eradicate disease as a whole.

On the one hand, vaccines have been proven to be highly effective in providing artificial immunity. One key example of success was the eradication of smallpox. It is one of only two known diseases that have been confirmed by the WHO to have been eradicated , with the last known case in 1977. The high mortality rate (30%) drove many to search for potential cures. The first form of smallpox vaccination was practised in 10th century China: smallpox scabs were blown up healthy people?s noses, who then developed a mild case of the illness and therefore developed immunity. The smallpox outbreak of the 16th century meant that the disease was the main cause of mortality in Europe during that period. As modern medicine progressed, an initial vaccine was proposed by Edward Jenner in 1796. The vaccine was developed further and rolled out across the world and smallpox ceased to be endemic. This established the ability of vaccinations to overcome disease, giving us hope that further advancements may provide us with herd immunity to many more sicknesses. Currently, the existence and spread of disease is being heavily mitigated by the existence of vaccines and it is therefore arguable that future

To conclude, although it is possible for a disease to be eradicated, there is far too much variation between transmission, zoonosis, and effective cures between types of diseases, for vaccines to be the sole method of achieving global immunity.

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News Can Mistletoe Ber r ies be Used as a Super glue?

Mar co Cina Rabin Mistletoe is an evergreen plant with white berries that parasitically grows in the branches of certain trees. Each mistletoe berry can produce up to two metres of a gluey thread called viscin, which allows the seeds of this parasitic plant to stick to and infect host plants. Until now, no one has fully investigated potential medical or technical uses of the glue itself.

3D structures. They believe that this means the substance could potentially be used as a wound sealant or skin covering.

The universities still have a lot of research to undertake in order to try to replicate the process. However, given the excellent properties of viscin, and the fact that mistletoe plants are abundant and biodegradable, these findings suggest that this remarkable plant might be utilised for its potential commercial value as an adhesive or superglue in the near future.

A recent paper from McGill University and the Max Planck Institute of Colloids and Interfaces suggests that through simple processing, viscin's ultra-stiff flexible fibres, which adhere to both skin and cartilage as well as to various synthetic materials, could have a range of applications in both biomedical and future technologies. The paper also suggested that viscin could be stretched into thin films or assembled into

H ow do H yper giants Die? Ar jun Bubbar On June 16th 2022, students at the University of Arizona recorded the death of a hypergiant in the Milky Way known as VY Canis Majoris. It stood more than 3,000 light-years away from the Earth. With an estimated mass of 17 times the Sun and a radius of 1,420 times greater ? namely 980 million kilometres ? it was considered one of the largest stars in the Milky Way. Tracing the molecular emissions in the outflows around the red hypergiant allowed them to

obtain the first detailed 3D map of the star's envelope. When hydrogen is exhausted from stars, it indicates the final stages of their life as their hydrogen and helium cores tend to burn. Supernovae, the brightest and most powerful explosions known to man, despite only occurring amongst the largest stars, are usually not visible in our galaxy owing to dust blocks. Astronomers estimate that only one or two supernovae will light up in a century.

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A New Black H ole?

Amaan Aziz-K han On May 12th 2022, a team of astronomers operating the Event Horizon Telescope released an image of the black hole at the centre of the Milky way, named Sagittarius A* (Sgr A*). The black hole M87 previously imaged at the centre of the galaxy, shown on the left of the image, is 2,000 times bigger than Sgr A*, but is also 2,000 times further away from Earth, allowing for a similar resolution in both images. The reason this image is such a big deal is that M87* was an unusually large black hole, whereas Sgr A* is much smaller and similar to the many black holes at the centre of other galaxies, meaning we have a much greater idea as to what these other black holes look like.

The colour we see in the image is produced by the swirling superhot clouds of gas orbiting Sgr A* moving at incredible speeds.

This image is striking evidence of a supermassive blackhole at the centre of our galaxy and this is the first time we have been able to see it, rather than only observe the effects it has on its surroundings.

Do Mummies Still Contain Ancient Str ains of Bacter ia?

Mar co Cina Rabin For the first time, researchers have reconstructed the DNA of an ancient strain of E. coli. To find the bacterium, the team turned to the mummified remains of a group of Italian nobles who were believed to have lived in the 16th century. Examining the mummy's gallbladder, the team was able to detect E. Coli, ?an opportunistic pathogen?(a pathogen that likely won't cause disease in a healthy host, but that can cause disease in an immunocompromised host). Using fragments from a gallstone, the team identified the E. coli and reconstructed its genome. This ancient strain is quite similar to a contemporary strain.

By studying ancient strains of E. coli, the researchers say we can learn more about its evolution. Today, for instance, some strains of E. coli are becoming increasingly resistant to antibiotics. The researchers hope that in the future, they may be able to explore how other 'hidden pathogens' have evolved.

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Physics T he Doppler Effect Adr ien Dur antel This equation can electromagnetic waves:

In the year 1842, Christian Doppler first noted the phenomenon that is now referred to as the ?Doppler effect,?paving the way for substantial improvements in fields including robotics, medicine, and astronomy.

be

used

for

Where ? = source wavelength, ?? is the change in wavelength recorded by the observer, f = source frequency, ?f = change in frequency recorded by the observer, v = magnitude of relative velocity between the source and the observer and c = speed of light.

The Doppler effect is the apparent change in frequency and wavelength of waves whenever the source of the waves is moving relative to an observer. When a source of waves is itself moving towards an observer, each new wave is emitted at a distance closer to the observer, causing a compression of waves, producing a higher frequency. The opposite is true when the source of the wave is moving away from the observer, with a stretching out of waves and a decreased frequency.

The equation can be used only for galaxies with speeds significantly lower than that of light.

The Doppler effect is used in innumerable applications including measuring the speed and direction of blood flow in organisms, echocardiograms, and satellites.

When looking at the absorption spectrum of a specific element and comparing it with the same spectrum observed in light from a faraway galaxy, we can detect any differences in the wavelengths of the absorption lines. These result from the relative motion between the galaxy and Earth. If the distance between the galaxy and Earth increases, there will be the perception of a decreased frequency of the light (?redshift? as wavelength increases, shifting to the red end of the visible light spectrum).

Conversely, if the distance between the galaxy and Earth decreases, there will be the perception of an increased frequency of light (?blueshift?as wavelength decreases, shifting to the blue end of the visible light spectrum) In the 1920s, Edwin Hubble analysed the Doppler shift in absorption spectra of distant

The Doppler effect is the result of the motion of the source, the observer, or even that of the medium depending on the type of wave (the phenomenon occurs for any type of wave).

Mathematically, the Doppler equation is given by:

Where f0 = observed frequency, fs = actual frequency of waves, v = speed of sound waves in medium, v0 = observer velocity, and vs = wave source velocity.

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precipitation, and determining what type of precipitation is falling (rain, snow, or hail).

Similarly, the speed of a tennis ball or of any moving object can be measured from the Doppler shift of the microwaves reflected off the ball.

galaxies, discovering that light from most galaxies was red-shifted and that the further the galaxy was, the greater the observed red shift. This is because the universe is expanding with the distance between galaxies increasing (the further apart two galaxies are, the greater the rate at which the distance increases). This technique can also determine the speed of stars and galaxy rotations. It is worth noting that for galaxies the cosmological redshift is used rather than the Doppler redshift as the wavelength at which radiation was originally emitted is lengthened as the wave travels through expanding space. Cosmological redshift considers stationary emitters and observers in expanding space (unlike Doppler shift, which requires at least one of the observer or emitter to move).

Doppler spectroscopy is a technique used to detect periodic velocity shifts in the stellar spectrum caused by an orbiting planet. Starlight is analysed for evidence that a star is being pulled back and forth by the gravitational pulls of orbiting planets.

Observations are made of the spectrum of emitted light to detect periodic variations in the star?s spectrum (the wavelength of some of the characteristic spectral lines will increase and decrease regularly over a period of time if an orbiting planet exists.

The mass of the planet can then be calculated though the accuracy of this value depending on the inclination of the planet?s orbit). This method?s limitations include the existence of variable stars and that the gas surrounding some stars can expand and contract.

Some types of weather radars locate areas of precipitation using the Doppler effect.

The radars transmit microwaves, and these are reflected off precipitation and back to a receiver. The wavelength of reflected waves will be Doppler-shifted depending on the relative motion of the weather system and consequently, the path of the weather system can be tracked. Modern weather radars are extremely sensitive, detecting the motion of individual droplets, measuring the intensity of the

In conclusion, the undoubtedly been scientific advances understood and will centuries to come.

Doppler effect has at the forefront of since it was first continue to be so for

Quantum Computing: Separ ating Fact fr om Myth Danny Cui In a paper published in Nature in October 2019, Google announced that it had demonstrated quantum supremacy. Their cutting-edge quantum processor, codenamed Sycamore, had performed a task that would take a state-of-the-art classical supercomputer approximately 10,000 years in a mere 200 seconds. This has

unquestionably raised the existing excitement surrounding the technology to a brand new level. However, the hype surrounding this exciting technology is often shrouded in myth. It is also not helped by countless news headlines' screaming the advent of the "Imminent Quantum Computing Apocalypse" following the arrival

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of the Google paper. These accounts are greatly exaggerated and do not tell the whole story ? that the task performed by Sycamore to demonstrate "quantum supremacy" is of no actual practical application and will not doom all of our encryption soon (although this is something to be aware of in the long term). None of the currently available demonstrations of "quantum supremacy" are applicable to any real practical computing situations, and the majority of these do not even use any input data.

Where |x?is a typical state of a qubit, and the coefficients a, and b are referred to as amplitudes of |0? and |1?. The square of the absolute value of the amplitude of a basis state gives the probability of obtaining it when measured. Continuing the example above, the probability of measuring |0? would be |a|2. Amplitudes can constructively and destructively interfere, much like amplitudes in a wave. Measuring the qubit will only return one of the states |0? and |1?, whose probabilities are given by the square of the absolute value of their amplitudes.

To separate the myth from the facts, we need to delve into some of the physics behind this technology. The basic unit of information that a quantum computer operates on is a qubit. A qubit can be any two-state quantum system. Common examples include the spin of an electron, where the two possible states are up or down; or the polarisation of a photon, where the two states are vertical polarisation and horizontal polarisation. Like its classical counterpart, the classical bit, the two states of a qubit correspond to the values 1 and 0. Unlike the classical bit, a qubit can be in a superposition of its two states 1 and 0. This is where a lot of the confusion about quantum computers comes from. In many popularised science articles online, superposition is commonly described as ?being in all possible states at once?, and the strength of quantum computing is described as ?being able to compute all possible answers simultaneously?. This is misleading and overly simplified.

What the superposition of a qubit really means is that the qubit is in a "complex linear combination" of the states 1 and 0, which are denoted as two vectors, |1? and |0? respectively. The state of a qubit is usually represented as a vector, where the states |1? and |0? are the basis. The state can hence be represented as a sum of |1? and |0?, each weighted with some complex coefficient, for example:

For a computer to be useful, it needs to have a measurable output. But because we can obtain only one of the basis states after measuring a qubit, this means that measuring an equal superposition of "all possible states at once" would really return one random answer, and to obtain all possible answers, in this case, is the equivalent of brute-forcing your way through, which is not efficient at all.

The key to efficient quantum computing is to devise an algorithm that will constructively interfere to increase the likelihood of a 'right answer', and destructively interfere to decrease the chance of a 'wrong answer', and do this faster than a classical computer. This is often tricky and especially since the answer is often not known in advance.

Existing quantum algorithms, such as the one devised by Shor (which performs prime factorisation almost exponentially faster than the current best classical algorithm), do this by exploiting specific mathematical structures in these problems. Only a narrow range of algorithms like these can take advantage of quantum computation.

To be able to break most of the encryption used today, we would need to have quantum computers able to effectively implement Shor?s algorithm. According to researchers at Google and Sweden?s KTH Royal Institute of Technology, for a quantum computer to be able to break a 2,048-bit RSA encryption, a

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quantum gates which can compare the states of the entangled qubits without actually measuring them, an error can be identified and corrected. However, the redundancy means that we would need many times the number of qubits that an algorithm logically requires, which increases the difficulty of implementation. There are other methods of reducing the errors in qubits, such as making them as stable as possible, which often involves keeping the device at a temperature just above absolute zero, or even a completely different but more stable approach, such as topological. However, keeping objects at a temperature close to absolute zero is hard, and building topological quantum computing hardware has been a really big challenge.

typical encryption used today, it would take eight hours on a computer with 20 million qubits. Most quantum computers as of present use fewer than 100 qubits, with larger quantum computers using just over 100. It will take decades until we will have quantum computers with 20 million qubits, and even longer for them to be commercially available. Mostly, this is because qubits are fragile and prone to error. One of the most prominent causes of error is decoherence ? where qubits are prematurely measured owing to unwanted interactions with the environment. This causes qubits to lose their ?quantum-ness?, taking on one of the two states |0? and |1?, and not a combination of the two.

A way of mitigating the effects of decoherence is through what is called ?Quantum Error Correction?. However, this often involves redundancy, where several physical qubits are used to logically represent a single qubit. These physical qubits are often entangled, meaning that a change to the state of one of the qubits instantaneously changes the state of the rest of them. Through the ingenious use of

Even though quantum computing is an exciting field of new technology, it is important to separate the myth from facts.

However, even looking past all the hype and myth surrounding this subject, quantum computing will undoubtedly be ground-breaking in its potential uses and applications, and will likely be a new and revolutionary tool in many different fields.

Centr ipetal For ce Max Satchell Centripetal force causes an object to travel in a circular path. It is often misunderstood but all too prevalent in our day to day lives.

Why do planets stay in orbit? And how does a loop-the-loop work? These are all questions that can be answered by understanding the centripetal forces present.

that a certain force may be called tension or weight. The best way to understand this is perhaps with an example. Imagine you are whirling around a string with a mass attached to its end in the air. Why does the mass move in a circular fashion? We should consider the forces acting on the mass at this moment.

The important force is the force denoted R. This refers to the tension in the string. In this scenario we say that the tension in the string acts as the centripetal force. Note that at any given moment the tension is always directed

First of all we must ask ourselves the question: what is a centripetal force?

The answer is that there is no force simply called ? centripetal force? in the same way

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this stage, the normal contact force acts entirely as the centripetal force, and for the centripetal force to have a constant magnitude, normal contact force must be at its greatest here. But what about when the carriage is at the top? Here both weight and normal contact force act downwards, and we know that the centripetal force must also act downwards, towards the centre of the loop.

At this point, both weight and normal contact force act as the centripetal force, and the normal contact force is at its minimum so that the magnitude of centripetal force remains constant, or zero.

towards the centre of the circle of motion and that the direction of motion, v is always perpendicular to the tension R. It is the combination of these two properties that causes the circular motion of the mass.

Now let us consider why the planets of our solar system remain in orbit around the Sun. In this case the weight of each planet acts as the centripetal force. At any given time each planet wants to travel in a straight line in some general direction away from the Sun. However, the gravitational pull of the Sun creates a force (the centripetal force) on these planets which always acts directly towards the Sun. Therefore, no matter where a certain planet is in its orbit, it will alway be pulled into a curved path. The International Space Station uses the exact same centripetal force in weight to stay in orbit around the Earth.

How about a more complex example, a loop-the-loop? The two forces acting on a carriage of a roller coaster at any given time are the normal contact force, exerted by the track on the carriage, and the weight of the carriage. In this case, the forces which act as the centripetal force are actually always changing, depending on the position of the carriage around the track. The key thing to understand is that the centripetal force must always have a constant magnitude, no matter where the carriage is, and must always point towards the centre of the loop.

So, when the carriage is at the bottom of the loop-the-loop, weight acts downwards, and the normal contact force acts upwards. At

Centripetal force is the reason why so many of the best childhood toys work. Swings, roller-coasters, merry-go-rounds, as well as events like the shot put and hammer. After all, it is essential for all circular motion.

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Psychology W hat is Addiction?

Var un Vashisht Addiction, or at least the possibility of addiction, has become increasingly prevelant, with almost everyone being addicted to something, whether it be food, coffee, drugs, alcohol or video games. But what actually causes this addiction, and how can we try to stop our own addictions?

pleasure for the person. Although it seems like it would demotivate them from doing that action further, it actually invigorates the person to repeat that action even more in an attempt to achieve that same feeling of pleasure they experienced when doing it for the first time. Whilst the level of pleasure would be reached with enough dopamine or endorphins, this further desensitises the dopamine and endorphin neurotransmitters, decreasing the pleasure from performing that action to a greater extent. This results in a vicious cycle where the person continues to try to experience that pleasure from carrying out that action and never ends up receiving it owing to the continual increase in tolerance in the dopamine and endorphin receptors.

The NHS defines addiction as the inability to ?have control over doing, taking or using something to the point where it could be harmful to you?. Whilst this certainly covers a lot of the common addictions well known to the public such as smoking and drinking, it also brings light to other activities that some people might refer to as an addiction, such as work or even shopping. This clearly indicates that it isn?t just chemical substances that cause an addiction. In fact, the main culprit behind addictions is the reward circuitry within the brain.

When carrying out these actions for the first time, neurotransmitters such as dopamine and endorphins are released towards the reward centre within the brain via the mesolimbic pathways. This novel feeling leads to a powerful feeling of pleasure.

Naturally, this leads them to want to carry out that action multiple times afterwards to continue feeling that same pleasure.

However, as they continue to repeat this over and over, the dopamine and endorphin receptors become less and less sensitive to the binding of their complementary neurotransmitters, resulting in a decrease in 53

Addictions can have profound effects on the body which differ depending on the addiction. Some may face financial damage owing to uncontrollable spending habits on addiction-related products (e.g cigarettes); even the act of buying can trigger the reward pathway. Substance misuse often has physiological effects, from emphysema caused by damage to the alveoli from smoking, to liver damage from excessive alcohol consumption. Addiction also has mental effects, such as an increased level of impulsivity and a diminished level of appropriate decision making. Attempting to stop the addiction generally results in withdrawal symptoms such as restlessness,

fatigue and anxiety, all of which usually cause a relapse into the addiction.

Whilst it does seem that you simply cannot escape your addiction, there are several things that can help. Some products such as nicotine patches contain the chemical that releases dopamine without the harmful side effects that come with it. Behavioural therapy can provide awareness of the cause of addiction to the person and gives counselling to alleviate the symptoms that come with it such as anxiety and depression. Finally, certain medications can be taken that mimic the effects of the addictive drug in order to ease withdrawal symptoms.

Does language Affect the Way in W hich We T hink?

Shivan Ar or a For millennia people have questioned whether language affects how we think, and many theories have been proposed. Most popularly, there is the Sapir-Whorf Hypothesis which is split into two subtheories: linguistic relativity and linguistic determinism. Linguistic relativity posits that different structures in different languages lead to non-linguistic cognitive differences and responses to the world.

These non-linguistic cognitive differences can be defined as differences in processes in the brain that are not related to the understanding and use of language within it ? such as recalling a mathematical formula.

Linguistic determinism, on the other hand, suggests that the language we speak determines our world view; given how strong of an effect it suggests, we can disregard it, at least until linguistic relativity

is found to be true. The influence of language can be examined in the realms of colour, time, space, orientation, and also in more abstract concepts, such as agency.

Firstly, we can examine the matter of colour.

Research has been conducted on the Himba people, a semi-nomadic Namibian tribe who live isolated from modern developments and have chosen to live traditionally. The people of the Himba tribe, who have no distinction between green and blue in their language, and no word for blue, took far longer to distinguish blue from a set of green than their English counterparts. However, on the other hand, due to their vast vocabulary for green colours, they could more quickly distinguish a different shade of green from a set of greens.

This suggests that they can indeed see the colour blue, however, the fact that their language doesn?t have an outright word and

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distinction for blue also appears to have influenced the way in which they perceive colour, a non-linguistic cognitive process.

This thus demonstrates support for linguistic relativity.

word for 'key', masculine in German, and feminine in Spanish, was described as 'golden' or 'intricate' in Spanish, and 'heavy' and 'serrated' in German.

Finally, we can examine the abstract concept of agency. Varying languages often have vastly different structures, for example, Spanish often employs the passive ?se? to express an accidental occurrence, rather than immediately directing the blame to the person. The following may be a likely occurrence: ?se rompió el florero? (the vase broke), rather than ?rompiste el florero?(you broke the vase). A study found that when comparing eye-witness memory of events between English and Spanish speakers, both groups described intentional agents of the action as agents, and had strong memories of these agents. However, English speakers tended to remember the agents of accidental events better than Spanish speakers, reflecting the difference in structure for accidental events specifically, whereas in Spanish the agent is often unspecified, suggesting an effect of the language they spoke upon the way they perceived the event.

Looking at time, a study of Mandarin-English bilingual speakers, and the way in which they organise time psychologically, was conducted and produced fascinating results.

In Mandarin, certain spatiotemporal constructions exist, which use spatial markers to reference time, such as ? ? ? ? (shàng ge x?ng q?), which literally means ?up week?, but is translated as ?last week?. They took photographs of mainstream Chinese actor Jet Li, and famous American actor Brad Pitt, and asked Mandarin-English bilingual speakers to arrange the photos in chronological order. They found that participants were more likely to organise Jet Li with a vertical Chinese language-influenced timeline, whereas they were more likely to organise Brad Pitt with a horizontal English timeline.

This demonstrates a clear influence of language upon thought, as the non-linguistic process of organising time is influenced by the language associated with each actor.

Overall, studies so far have found language to have influenced the way in which people think, albeit mostly in the specific scenarios of colour discrimination and time organisation. This raises issues for real life implications of such an influence: given the general weakness of experimentally recorded effects, it is more reasonable to suggest that language does affect our thoughts and perceptions, however in a day-to-day context, the effect is negligible.

Many languages have grammatical gender that is seemingly randomly assigned. For example, ?Das Mädchen?in German, meaning ?the girl?, is neuter. This begs the question, 'does the grammatical gender of a noun give a gendered perception? A study carried out in 2003 found that German speakers associated feminine gendered nouns with stereotypically feminine attributes, and vice versa for masculine nouns. The same was found in Spanish speakers. Spanish tended to say 'sturdy' and 'towering', but German tended to say 'beautiful' or 'elegant'. The same occurred the other way round: the

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