Science Now: Science Stories From June 2015 - Part 2


MATH

If you are skeptical about the role math and physics can play in your everyday life, think again - physicists studied the lead changes in a number of team sports like football and basketball, and found that the number of lead changes in a game follows mathematical rules governing a "random walk".

[Photo credit: wallpaperup.com]

A random walk is essentially the mathematical description of random movement, and is often used to model phenomena subject to fluctuations such as the movement of molecules and stock prices. In other words, leads in a game tend to fluctuate randomly. Based on this model, the researchers' predictions were found to be highly accurate, when plotted and compared to historical statistics of thousands of games1.

Lead changes are most likely to occur in the first few minutes and in the last of a game, which is also when the biggest point difference tends to be retained. They even suggest an equation that can predict when a lead is safe, based on how big the point difference is and how much time is left in the game2.

L = .4602 √t, where L is the lead and t is the number of seconds remaining

                           
                                                    [Photo credit: TheLasallian.com]


Using this equation, you can determine what the lead and remaining time have to be for a team to have a 90% chance to maintain that lead. For example, while it might sound intuitive for a team leading by around 10 points in the last few minutes of the game to have a high chance of winning, the researchers say this will also follow for an 18 point lead at the end of the first half.


[Photo credit: rogerebert.com]

The utility of math doesn't just apply to sports; it seems to also extend to music, where scientists have found that a professional drummer's rhythm follows fractal patterns. Math has long been considered to have close associations with music, and while we may be tempted to assume mathematical patterns give music a robotic, hyper-precise beat, fractal patterns can actually generate human-like rhythms3.This is also because fractals aren't limited to visual, self-similar patterns; they also occur in time, but are hard for the human ear to perceive.

[Photo credit: wallpaperbackgrounds.com]

The physicists of the Max Planck Institute for Dynamics and Self Organization studied the drum techniques of Toto's Jeff Porcaro, in particular, on the 1982 recording of "I Keep Forgettin'". The team analyzed the amplitude and timing of the notes, and found that they indeed formed fractal patterns4. The team plans to use this work to eventually develop an algorithm that can make computer-generated music sound more human, and can be used by electronic musicians.


EVOLUTION


Why do humans like drinking so much? Apparently, we are not unique among the primates in this fondness for inebriation - chimpanzees have been found to also drink palm wine for leisure, and this may shed light on how we evolved a taste for alcohol in the first place.


The ability to metabolize alcohol begins with the alcohol dehydrogenase enzyme (ADH4), with some primates possessing a more effective form than in others. Ten million years ago, our ancestors evolved a version of the enzyme that was 40 times more efficient at metabolizing ethanol5. The scientists hypothesize that this may have arisen because our ancestors would eat fruits that had fallen from trees, which would begin to ferment and build up ethanol - leading to a selective pressure towards its effective breakdown. Otherwise, the apes would become drunk too easily, or even develop alcohol poisoning.

                                                         [Photo credit: Aprilart Studios]

A year later, a team of primatologists found evidence that other apes tolerate ethanol: they observed a troop of chimps for 17 years, using video cameras. The chimps would drink palm wine that was collected by the members of the village, using drinking cups they fashioned from folded leaves6. The chimps engaged in 20 drinking sessions total.


Have you ever wondered how a turtle looks without its shell? The first full-shelled turtles appeared approximately 205 million years ago, but paleontologists recently unearthed around two dozen fossils of Pappochelys rosinae: a likely missing link between prototurtles and modern ones, dating back to 240 million years7.

                                                 [Photo credit: Rainier Schoch, wikipedia.com]


Found in southern Germany, the adults of the species are around 20 centimeters long, with a whiplike tail. Its ribs are broad and dense, with a T-shaped cross section. In modern turtles, these ribs fuse along with the bones in the pectoral girdle to form its upper shell (carapace). Pappochelys also has belly ribs, which broaden and fuse in modern turtles to form its lower shell (plastron).

                                                 [Photo credit: Luke Norton, pulseheadlines.com]

Its dense bones would not only have given it enough weight to forage for food on the bottom of the lake, but they would also give them protection from predators lurking in the lake and hoping for a bite.


The ray-finned fishes (Actinopterygii) are an incredibly diverse and dominant group, constituting nearly all modern fish species, and containing more species than the birds, mammals, and reptiles combined8. However, this wasn't always the case 65-66 million years ago, around the time of the Cretaceous extinction event.

                                                       [Photo credit: ZME Science website]

Scientists studied microfossil teeth and the dermal scales of sharks that were preserved in deep-sea sediments to study the fish community during this period. They found that the sharks actually outnumbered the ray-finned fish during the Cretaceous. After the extinction event, the ray-finned fish teeth increased dramatically, and also became much bigger. The sharks persisted through the event, but stagnated as the ray-finned fish diversified greatly9.


MEDICINE


While it is normally difficult to transmit Trypanosoma cruzi (the agent behind Chagas disease) from kissing bugs, the disease is still rife in some communities in South America, such as Arequipa, Peru. Scientists have found that the possible answer may lie with one animal that the Peruvians consider a delicacy: the guinea pig.

                                                                     [Photo credit: user "Jg4817", wikipedia.com]


Guinea pigs are carriers of T. cruzi, and also infect the insects that drink their blood. The pigs are kept concentrated in pens, in preparation for the Peruvians' yearly guinea pig roasts. This way, T. cruzi can easily find its way to a human host, and keep Chagas prevalence high10.


                                                            [Photo credit: CDC website]


In the fight against Ebola, one major concern has been the limitation of its diagnostic test: the patients' blood would be transported to laboratories for testing by real-time PCR, resulting in a significant delay. Thankfully, a quick diagnostic test has been developed, called the ReEBOV Antigen Rapid Test Kit. With a single finger prick, a diagnosis can be given in a matter of just 15 minutes11.


                                                      [Photo credit: GlobalNews website]

Using antibodies toward the EBOV VP antigen, the test captures any antigens present in the blood sample so that they form an antibody-antigen complex. The complexes are detected by the test, generating a pink-red color12. With this development, Ebola outbreaks would be much easier to identify and to control.
[Photo credit: John Moore, Getty Images]

Lastly, with insulin injections as a painful ritual for many diabetics, a potential therapy presents itself in the form of an insulin patch. Scientists from the University of California have developed a "smart insulin patch", which contains a microneedle array with glucose-responsive vesicles, containing insulin and glucose oxidase enzyme13.

[Photo credit: The Herald website]

In a hyperglycemic (high sugar) state, the vesicles will release insulin into the blood, helping to regulate one's blood sugar level. This has been experimentally shown to work in mouse models that were chemically induced with type 1 diabetes. Because the patch responds quickly and is also easily administered, it is projected for clinical trials in the future.


REFERENCES

1. Clauset, A. et al. (2015). Safe leads and lead changes in competitive team sports. Phys. Rev. E 91(6): 062815.
2. Woo, M. (June 18 2015). Lucky Bounce. Retrieved from Slate website.
3. Klein, K. (2015). The secret to groovy drumming may be math. Retrieved from Science magazine website.
4. Rasanen, E. et al. (2015). Fluctuations of hi-hat timing and dynamics in a virtuoso drum track of a popular music    recording. PLoS ONE 10(6): e0127902.
5. Carrigan, MA. et al. (2014). Hominids adapted to metabolize ethanol long before human-directed fermentation. PNAS  112(2): 458-463.
6. Hockings, KJ et al. (2015). Tools to tipple: Ethanol ingestion by wild chimpanzees using leaf-sponges. Royal Society  Open Science 2: 150150.
7. Schoch, RR. & Sues, H-D. (2015). A Middle Triassic stem-turtle and the evolution of the turtle body plan. Nature; doi:  10.1038/nature14472.
8. Faircloth, BC. et al. (2013). A phylogenomic perspective on the radiation of ray-finned fishes based upon targeted  sequencing of ultraconserved elements (UCEs). PLoS ONE 8(6): e65923.
9. Silbert, EC. & Norris, RD. (2015). New age of fishes initiated by the Cretaceous-Paleogene mass extinction. PNAS;  doi: 10.1073/pnas.1504985112.
10. Levy, MZ. et al. (2015). Bottlenecks in domestic animal populations can facilitate the emergence of Trypanosoma cruzi, the aetiological agent of Chagas disease. Proceedings B 282(1810).
11. Broadhurst, MJ et al. (2015). ReEBOV Antigen Rapid Test kit for point-of-care and laboratory-based testing for  Ebola virus disease: A field validation study. The Lancet.
12. World Health Organization (2015). Emergency Use Assessment and Listing for Ebola Virus Disease IVDS Public Report. Product: ReEBOV Antigen Rapid Test Kit. (EA 0011-011-00).
13. Yu, J. et al. (2015). Microneedle-array patches loaded with hypoxia-sensitive vesicles provide fast glucose-    responsive insulin delivery. PNAS 112(27): 8260-8265.

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