WikiJournal of Science/Volume 1 Issue 1
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VOLUME 1 (2018)
ISSUE 1
Previous issue
Author: Mike Christie
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. [...] The method was developed in the late 1940s by Willard Libby, who received the Nobel Prize in Chemistry for his work in 1960. It is based on the fact that radiocarbon (14 C) is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14 C combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 14 C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14 C it contains begins to decrease as the 14 C undergoes radioactive decay. Measuring the amount of 14 C in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died. The older a sample is, the less 14 C there is to be detected, and because the half-life of 14 C is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples. Research has been ongoing since the 1960s to determine what the proportion of 14 C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14 C in different types of organisms (fractionation), and the varying levels of 14 C throughout the biosphere (reservoir effects). Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s. Because the time it takes to convert biological materials to fossil fuels is substantially longer than the time it takes for its 14 C to decay below detectable levels, fossil fuels contain almost no 14 C, and as a result there was a noticeable drop in the proportion of 14 C in the atmosphere beginning in the late 19th century. Conversely, nuclear testing increased the amount of 14 C in the atmosphere, which attained a maximum in about 1965 of almost twice what it had been before the testing began. Measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14 C atoms in a sample. Accelerator mass spectrometry (AMS) has since become the method of choice; it counts 14 C atoms in the sample directly, rather than just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly. The development of radiocarbon dating has had a profound impact on archaeology: in addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances, and it has allowed key transitions in prehistory to be dated, such as the end of the last ice age. doi: 10.15347/WJS/2018.006
Authors: Guy Vandegrift, A card game for Bell's theorem and its loopholes
In 1964 John Stewart Bell made an observation about the behavior of particles separated by macroscopic distances that had puzzled physicists for at least 29 years, when Einstein, Podolsky and Rosen put forth the famous EPR paradox. Bell made certain assumptions leading to an inequality that entangled particles are routinely observed to violate in what are now called Bell test experiments. As an alternative to showing students a "proof" of Bell's inequality, we introduce a card game that is impossible to win. The solitaire version is so simple it can be used to introduce binomial statistics without mentioning physics or Bell's theorem. Things get interesting in the partners' version of the game because Alice and Bob can win, but only if they cheat. We have identified three cheats, and each corresponds to a Bell's theorem "loophole". This gives the instructor an excuse to discuss detector error, causality, and why there is a maximum speed at which information can travel.
doi: 10.15347/WJS/2018.005
Authors: Tatiana P. Soares da Costa, Cody J. Hall
Amino acids are an essential building block of all life and are commonly incorporated into extending polypeptide chains to produce proteins. Lysine is one such amino acid and is classified as basic and positively charged at physiological pH due to the presence of an additional amino chemical group on the side chain. Lysine has two main biosynthetic pathways, namely the diaminopimelate and α-aminoadipate pathways, which employ different enzymes and substrates and are found in different organisms. Lysine catabolism occurs through one of several pathways, the most common of which is the saccharopine pathway. Lysine plays several roles in humans, most importantly proteinogenesis, but also in the crosslinking of collagen polypeptides, uptake of essential mineral nutrients, and in the production of carnitine, which is key in fatty acid metabolism. Furthermore, lysine is often involved in histone modifications, and thus, impacts the epigenome. Due to the importance of lysine in several biological processes, a lack of lysine can lead to several disease states including; defective connective tissues, impaired fatty acid metabolism, anaemia, and systemic protein-energy deficiency. In juxtaposition to this, an overabundance of lysine, caused by ineffective catabolism, can cause severe neurological issues.
doi: 10.15347/WJS/2018.004
Authors: Shih Chieh Chang, Saumya Bajaj, George Chandy
Stichodactyla toxin (ShK) is a 35-residue basic peptide from the sea anemone Stichodactyla helianthus that blocks a number of potassium channels. An analogue of ShK called ShK-186 or Dalazatide is in human trials as a therapeutic for autoimmune diseases.
doi: 10.15347/WJS/2018.003
Author: Boris Tsirelson
While modern mathematics use many types of spaces, such as Euclidean spaces, linear spaces, topological spaces, Hilbert spaces, or probability spaces, it does not define the notion of "space" itself. [...] A space consists of selected mathematical objects that are treated as points, and selected relationships between these points. The nature of the points can vary widely: for example, the points can be elements of a set, functions on another space, or subspaces of another space. It is the relationships that define the nature of the space. More precisely, isomorphic spaces are considered identical, where an isomorphism between two spaces is a one-to-one correspondence between their points that preserves the relationships. For example, the relationships between the points of a three-dimensional Euclidean space are uniquely determined by Euclid's axioms, and all three-dimensional Euclidean spaces are considered identical. Topological notions such as continuity have natural definitions in every Euclidean space. However, topology does not distinguish straight lines from curved lines, and the relation between Euclidean and topological spaces is thus "forgetful". Relations of this kind are sketched in Figure 1, and treated in more detail in the Section "Types of spaces". It is not always clear whether a given mathematical object should be considered as a geometric "space", or an algebraic "structure". A general definition of "structure", proposed by Bourbaki, embraces all common types of spaces, provides a general definition of isomorphism, and justifies the transfer of properties between isomorphic structures. doi: 10.15347/WJS/2018.002 Editorial | The aims and scope of WikiJournal of Science
Authors: Thomas Shafee, WikiJournal of Science editorial board
WikiJournal of Science is an open access, peer reviewed journal, free of publication charges for its authors. It has Wikipedia-integration as a key feature and aims to encourage and recognise contributions to Wikipedia by academics. It is a sister journal to the established WikiJournal of Medicine, and covers science, technology, engineering and mathematics. This editorial will discuss the current aims and future scope of the journal, as well as the WikiJournal format in general.
doi: 10.15347/WJS/2018.001
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