Science, Art, Litt, Science based Art & Science Communication
Qs people asked me on science and my replies to them - Part 269
Q: Is slime solid or liquid?
Krishna: Slime is a non-Newtonian fluid.
A non-Newtonian fluid/liquid is neither a liquid nor a solid. So you can both pick it up with your hands like a solid, and it will ooze like a liquid. Much like a liquid, slime doesn't have its own shape, so it moulds to whatever container it is placed in.
Although the precise definition is somewhat complex, liquids that pour and behave like water, oil and alcohol, for example, are called Newtonian fluids. Some liquids, however, do not obey Newton’s model of viscosity, because their viscosity can be affected by factors other than temperature. These fluids are termed non-Newtonian fluids.
Solids consist of tightly packed particles called molecules or atoms that clasp onto each other so the solid holds its shape.
Liquids have particles that can slide over and around one another, allowing the fluid to flow. Only adding or taking away heat can make some liquids, like water or oil, flow better or worse. These are called Newtonian liquids.
Non-Newtonian liquids, such as ketchup and slime, are different. Manipulations like squeezing, stirring or agitating can also change how they flow. Sometimes they can become so viscous—or have such a hard time flowing—that they could easily be mistaken for a solid.
The slime sometimes feel like a solid and sometimes like a fluid? This is expected.
This type of slime thickens or becomes harder or more viscous when you squeeze or stir it. This happens because it is made up of very long particles that are cross-linked. When you leave the particles alone they will coil up, and the coils can slide over each other. When you apply pressure by squeezing or stirring, some coils unwind and become entangled, making it harder for the slime to flow.
The viscosity of a non-Newtonian fluid can generally be affected by the application of what is called a shear stress. Examples of shear stresses are squeezing, stirring, agitating, or applying mechanical pressure to the surface of a fluid. Any of these things can greatly affect the viscosity of a non-Newtonian substance. But you can agitate water (a Newtonian substance) all day long, and its viscosity will not be affected.
Krishna: Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The identification of signatures of adaptations to such dietary changes in the genome of extant primates (including humans) may shed light not only on the evolutionary history of our species, but also on the mechanisms that underlie common metabolic diseases in modern human populations. In a review, researchers provided a brief overview of the major dietary shifts that occurred during hominin evolution, and discussed the methods and approaches used to identify signals of natural selection in patterns of sequence variation. They then reviewed the results of studies aimed at detecting the genetic loci that played a major role in dietary adaptations and conclude by outlining the potential of future studies in this area (1).
The summary of the research says (1) ....
- Humans inhabit diverse environments and use various subsistence strategies that are associated with selective pressures on human metabolism and homeostasis.
- Evolutionary genetic approaches can detect episodes of genetic adaptation under some scenarios but have limited power in the case of selection acting on standing variants rather than new advantageous mutations.
- Genes involved in metabolism carry signatures of selection in single-gene and genomewide studies.
- Other categories of genes with potential signals of selection are chemosensory perception, appetite control, and those involved in the development of the digestive system.
- The molecular genetic evidence for diet-related adaptations in human evolutionary history is often lacking a full functional validation and is biased toward recent time periods.
In the first, published in 2009, scientists identified a genetic mutation in modern humans that allows certain toxins, including those found in smoke and smoked food, to be metabolized at a safe rate. The same genetic sequence was not found in other primates, including ancient hominins such as Neanderthals and Denisovans.
As humans now dominate nearly every environment on Earth in one way or another, a new factor has entered the evolutionary equation – us
Evolutionary time – at least for larger, more complex organisms – can be slow. This leaves many animals unable to adapt fast enough to cope with a human-dominated planet, with extinction currently up to 1,000 times greater than the rate at which species might be expected to disappear without human interference.
But rapid change is also possible, via an inbuilt genomic plasticity that allows individual animals to draw on a range of body plans and behaviours best suited to new opportunities and pressures. So-called microevolutions can transpire in the time of just a handful of generations.
A study by researchers at the University of Montreal, published online in the European Journal of Applied Physiology, takes a very detailed look at the kinetics of water absorption and offers some answers.
The study gave 36 volunteers 300 ml. of ordinary bottled water, “labelled” with deuterium (an isotope of hydrogen than contains a proton and a neutron instead of just a proton) to allow the researchers to track how much of that specific gulp of water was found at different places in the body. They found that the water started showing up in the bloodstream within five minutes; half of the water was absorbed in 11-13 minutes; and it was completely absorbed in 75-120 minutes.
Q: Why don't NLP trainers get that NLP is pseudoscience?
Neuro-linguistic programming (NLP) is a way of changing someone's thoughts and behaviors to help achieve desired outcomes for them. If you have anxieties and phobias some people say they can treat you by using NLP. But the neuro-scientists I spoke to expressed their reservations regarding NLP's efficiency.
There is no genuine evidence that NLP works. And anecdotal evidence doesn't count in science. The lack of formal regulation and NLP's commercial value mean that claims of its effectiveness can be anecdotal or supplied by an NLP provider. NLP providers will have a financial interest in the success of NLP, so we cannot use their evidence.
Research on NLP has produced mixed results.
Some studies have found benefits associated with NLP. For example, a study published in the journal Counselling and Psychotherapy Research found psychotherapy patients had improved psychological symptoms and life quality after having NLP compared to a control group ( I must add here that psychology is a controversial subject and most of the results obtained in the subject were found to be not reproducible and therefore is not considered as true science by many).
However, a review published in The British Journal of General Practice of 10 available studies on NLP was less favorable. It concluded there was little evidence for the effectiveness of NLP in treating health-related conditions, including anxiety disorders, weight management, and substance misuse. This was due to the limited amount and quality of the research studies that were available, rather than evidence that showed NLP did not work.
In 2014, a report by the Canadian Agency for Drugs and Technology in Health found no clinical evidence for the effectiveness of NLP in the treatment of PTSD, GAD, or depression.
However, a further research review published in 2015 did find NLP therapy to have a positive impact on individuals with social or psychological problems, although the authors said more investigation was needed.
The theoretical basis for NLP has also attracted criticism for lacking evidence-based support.
A paper published in 2009 concluded that after three decades, the theories behind NLP were still not credible, and evidence for its effectiveness was only anecdotal.
A 2010 review paper sought to assess the research findings relating to the theories behind NLP. Of the 33 included studies, only 18 percent were found to support NLP's underlying theories.
So, despite more than 4 decades of its existence, neither the effectiveness of NLP or the validity of the theories have been clearly demonstrated by research. Also, it is worth noting, that research has mainly been conducted in therapeutic settings, with few studies into the effectiveness of NLP in commercial environments and therefore, are highly unreliable. Studying how well NLP works has several practical issues as well, adding to the lack of clarity surrounding the subject. For example, it is difficult to directly compare studies given the range of different methods, techniques, and outcomes. Human psychology differs from person to person and therefore you don't get uniform results in psychology and it is difficult to establish facts. Moreover, we cannot rely on commercial establishments' research as it would definitely biased towards their business.
Without valid scientific evidence, I will not recommend it. No genuine scientist or doctor would recommend it either.
Now it is up to you to decide whether to go for it or not.
Q: My father needs a kidney and my mother wants me to donate my kidney, but I am only 20 years old. What should I do?
Not because the kidney didn’t work, but because her dad developed fungal infection and it spread to the brain (causing fatal meningoencephalitis) because of the immunosuppressant drugs he took. The kidney worked well till the end.
My colleague is doing well, she didn’t develop any complications because of her operation or losing one of her kidneys. Her only complaint is her sacrifice went in vain.
I told you this story to make you think more clearly.
In the end it is you who should decide what to do after considering all the pros and cons.
Q: Which came first, the universe or time?
Krishna: According to the standard big bang model of cosmology, time began together with the universe in a singularity approximately 14 billion years ago.
http://philsci-archive.pitt.edu/5312/1/BeginningOfTime.pdfWithout science this universe won’t exist in the first place. Because it is based on scientific principles. Science controls and runs this universe.
Without science - the study with which we understand the universe around us, half of the population would die of hunger (because there won't be benefits brought by agricultural revolution). Most of the rest who survive hunger would die of deadly diseases ( because there won't be drugs to cure them). Your average life span would be reduced to 30-40 years again ( because of poor nutritional statuses and diseases). Rest of the people would die of natural calamities like cyclones, hurricanes, earth-quakes, etc.
What would remain then? Empty Earth!
Humanity is surviving because of science now. If it survives in the future, it is because of science.
Q: What is epigenetics?
Krishna: Epigenetics describes changes in genetic information that do not alter the sequence of the genes themselves, but influence their activity.
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