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Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 11:14am

**How to figure out what you don't know

Increasingly, biologists are turning to computational modeling to make sense of complex systems. In neuroscience, researchers are adapting the kinds of algorithms used to forecast the weather or filter spam from your email to seek insight into how the brain's neural networks process information.

Testing various computational models of the nervous system, researchers have found that just because a model can make good predictions about data does not mean it reflects the underlying logic of the biological system it represents. Relying on such models without carefully evaluating their validity could lead to wrong conclusions about how the actual system works.

By building and comparing several models of neural signaling, Engel and Genkin found that good predictive power does not necessarily indicate that a model is a good representation of real neural networks. They found that the best models were instead those that were most consistent across multiple datasets. This approach won't necessarily work for all situations, however, and biologists may need alternative methods of evaluating their models. Most importantly, Genkin said, "We shouldn't take anything for granted. We should check every assumption we have."

Genkin, M., Engel, T.A. Moving beyond generalization to accurate interpretation of flexible models. Nat Mach Intell (2020). doi.org/10.1038/s42256-020-00242-6

https://techxplore.com/news/2020-10-figure-dont.html?utm_source=nwl...

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 11:02am

Microplastics in groundwater (and our drinking water) present unknown risk

Microplastics (plastics <5mm) and their negative health impacts have been studied in oceans, rivers, and even soils, and scientists are beginning to grapple with the myriad human health impacts their presence might have. One understudied, but critical, link in the cycle is groundwater, which is often a source of drinking water.
While microplastics in groundwater likely affect human health, only a handful of studies have examined the abundance and movement of microplastics in groundwater. This gap means the potential for adverse health effects remains largely unknown.
Microplastics pose multiple physical and chemical risks to the ecosystems where they're present, and those risks are exacerbated by plastics' longevity in natural environments. Since they're plastic, they're very durable which is why plastic is great. But it doesn't degrade easily. Microplastics' ability to linger in their environments for decades or longer likely has cumulative detrimental effects on both the organisms and quality of the ecosystem. Their chemical threat stems largely from their ability to transport harmful compounds on their surfaces; when organisms at the base of the food chain ingest microplastics, they ingest the toxins, too. As larger organisms consume the smaller ones, the toxins can build up (a process called bioaccumulation), eventually resulting in responses like organ dysfunction, genetic mutation, or death. Cave ecosystems are known for being super fragile to begin with. All the cave organisms—salamanders, blind fish—are sensitive, so any contaminants that are introduced could damage those ecosystems.
Groundwater can stay in the same aquifer for tens to hundreds of years, or even longer. Combining that long residence time with plastics' resistance to degradation means that those chemical effects could effectively build up in the water and in any organisms within it, increasing the likelihood of toxic bioaccumulation. Together, these could result in long-term contamination of water sources with poorly-understood health effects and ecosystem damage.
Researchers found that while microplastics do increase in groundwater during a flood event, there's also a second peak in microplastics after the flooding has begun to wane. Their explanation is that there are two sources of microplastics for groundwater: those that are already in the subsurface, and those that are newly delivered from the surface. Finding so much plastic later on in the flood, thinking that it could be coming from the surface... is important to understand the sourcing of microplastics in the groundwater. Knowing where the plastic is coming from could help mitigate future contamination.

Paper 23-1: Quantifying microplastic debris sourcing and transport for a karst aquifer
Abstract Link: gsa.confex.com/gsa/2020AM/meet … app.cgi/Paper/355066

https://phys.org/news/2020-10-microplastics-groundwater-unknown.htm...

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 10:58am

Mythbusting: Five common misperceptions surrounding the environmental impacts of single-use plastics

Five misperceptions surrounding the environmental impacts of single-use plastic.

• Plastic packaging is the largest contributor to a product's environmental impact. In reality, the product inside the package usually has a much greater environmental impact.
• The environmental impacts of plastics are greater than any other packaging material. Actually, plastic generally has lower overall environmental impacts than single-use glass or metal in most impact categories.
• Reusable products are always better than single-use plastics. Actually, reusable products have lower environmental impacts only when they are reused enough times to offset the materials and energy used to make them.
• Recycling and composting should be the highest priority. Truth be told, the environmental benefits associated with recycling and composting tend to be small when compared with efforts to reduce overall consumption.
• "Zero waste" efforts that eliminate single-use plastics minimize the environmental impacts of an event. In reality, the benefits of diverting waste from the landfill are small. Waste reduction and mindful consumption, including a careful consideration of the types and quantities of products consumed, are far larger factors dictating the environmental impact of an event.

https://phys.org/news/2020-10-mythbusting-common-misperceptions-env...

Five misperceptions surrounding the environmental impacts of single-use plastic, Environmental Science & Technology (2020). pubs.acs.org/doi/10.1021/acs.est.0c05295

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 10:51am

Estimating risk of airborne COVID-19 with mask usage, social distancing

The continued increase in COVID-19 infection around the world has led scientists from many different fields, including biomedicine, epidemiology, virology, fluid dynamics, aerosol physics, and public policy, to study the dynamics of airborne transmission.

Employing basic concepts of fluid dynamics and the known factors in airborne transmission of diseases, the researchers propose the Contagion Airborne Transmission (CAT) inequality model. While not all factors in the CAT inequality model may be known, it can still be used to assess relative risks, since situational risk is proportional to exposure time.

Using the model, the researchers determined protection from transmission increases with physical distancing in an approximately linear proportion.

If you double your distance, you generally double your protection. This kind of scaling or rule can help inform policy."

The scientists also found even simple cloth masks provide significant protection and could reduce the spread of COVID-19.

 Any physical activity that increases the breathing rate and volume of people will increase the risk of transmission. These findings have important implications for the reopening of schools, gyms, or malls.

Rajat Mittal et al, A mathematical framework for estimating risk of airborne transmission of COVID-19 with application to face mask use and social distancing, Physics of Fluids (2020). DOI: 10.1063/5.0025476

https://phys.org/news/2020-10-airborne-covid-mask-usage-social.html...

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 9:41am

Insects Play a Key (And Also Icky Role) in Decomposition by Turning Corpses Into Bones

Life after death: How insects rise from the dead and transform corpses into skeletons

While skeletons are universally considered symbols of death, the process of turning a newly dead animal into a bony skeleton relies on an explosion of life that ushers in the process of decomposition. Much of this transformative process is performed by wriggling, scuttling, scurrying insects.

Through decades of careful observation and experimentation, entomologists have described a five-stage model of decomposition. This model explains how insects, in close collaboration with microorganisms, transform a warm body into a pile of bones while simultaneously recycling carbon, nitrogen, phosphorous, and numerous other nutrients so that other living things may grow and thrive.

https://theconversation.com/life-after-death-how-insects-rise-from-...

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 8:03am

The pseudo-science of phrenology

https://www.thecourier.co.uk/fp/nostalgia/from-the-archives/1668244...

Comment by Dr. Krishna Kumari Challa on November 1, 2020 at 7:11am

Artificial intelligence model detects asymptomatic Covid-19 infections through cellphone-recorded coughs

Asymptomatic people who are infected with Covid-19 exhibit, by definition, no discernible physical symptoms of the disease. They are thus less likely to seek out testing for the virus, and could unknowingly spread the infection to others.

But it seems those who are asymptomatic may not be entirely free of changes wrought by the virus. MIT researchers have now found that people who are asymptomatic may differ from healthy individuals in the way that they cough. These differences are not decipherable to the human ear. But it turns out that they can be picked up by artificial intelligence.

In a paper published recently in the IEEE Journal of Engineering in Medicine and Biology, the team reports on an AI model that distinguishes asymptomatic people from healthy individuals through forced-cough recordings, which people voluntarily submitted through web browsers and devices such as cellphones and laptops.

The researchers trained the model on tens of thousands of samples of coughs, as well as spoken words. When they fed the model new cough recordings, it accurately identified 98.5 percent of coughs from people who were confirmed to have Covid-19, including 100 percent of coughs from asymptomatics — who reported they did not have symptoms but had tested positive for the virus.

https://news.mit.edu/2020/covid-19-cough-cellphone-detection-1029

https://researchnews.cc/news/3340/Artificial-intelligence-model-det...

Comment by Dr. Krishna Kumari Challa on October 31, 2020 at 11:26am

The Science of Nerdiness

It’s a neurotransmitter thing

Do you get excited and energized by the possibility of learning something new and complex? Do you get turned on by nuance? Do you get really stimulated by new ideas and imaginative scenarios?

If so, you may have an influx of dopamine in your synapses, but not where we traditionally think of this neurotransmitter flowing.

https://www.scientificamerican.com/article/the-science-of-nerdiness...

Comment by Dr. Krishna Kumari Challa on October 31, 2020 at 9:28am

Sci-com: What a link between chocolate and Nobel prizes reveals

https://theconversation.com/what-a-link-between-chocolate-and-nobel...

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**Mouth Bacteria Have Been Linked to Severe Forms of Inflammatory Bowel Disease

A genetic analysis of more than a dozen strains of one common bacterium, Campylobacter concisus, has uncovered a short sequence of DNA that might explain why this guy is a law-abiding citizen when at home in the mouth, but a potential terrorist in the gut.

"Oral bacteria enter the digestive system every day when we swallow food or saliva. Most of the bacteria are killed by acids in the stomach, but some can survive and colonise in the intestines. The bacteria might not have colonised for long, but the mouth keeps bringing a constant supply of new bacteria – that's the problem.

Generally speaking, many microbes in the genus Campylobacter are bad news for the human digestive system. If you've ever had a gut-wrenching stomach bug that's sent you running for the bathroom while on an overseas holiday, there's a good chance this tiny horror was behind it.

Since such disease-causing species are typically at home in other animals' intestines, we tend to pick them up by consuming contaminated meat or water.

C. concisus isn't quite like its more pathogenic cousins. This species we can call our own, living happily under an ocean of spit in virtually all healthy humans.

But in recent years, medical researchers have suspected C. concisus might not always be the peaceful citizen we'd expected it to be. Bacterial markers associated with the microbe are suspiciously linked with active incidences of the intestinal condition Crohn's disease, for example.

Together with ulcerative colitis, Crohn's falls into a category of IBD characterised by a serious inflammation of the gut wall and surrounding tissue. The result is anything from diarrhoea and discomfort to blood in the stool, agonising pain, and weight loss.

In the cases where drugs or lifestyle changes do little to help, surgical 

intervention can be necessary, making it one serious illness to contend with.

Exactly what sets these inflammatory bowel diseases off in the first place isn't entirely clear. Diet and stress are thought to merely aggravate symptoms, with genetics, medications, and environment all playing a potential role in their development.

https://www.sciencealert.com/your-mouth-bacteria-might-be-behind-se...

Comment by Dr. Krishna Kumari Challa on October 31, 2020 at 9:20am

A color-changing material inspired by chameleon skin

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