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Sat, 20 Jul 2019
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Evolution - A Modern Fairy Tale

Evolution
Evolution is an amazing thing. It consists of a vast number of strange events that have almost zero probability of happening. It is so unbelievable that nobody would take it seriously except for the fact that EvolutionIsTrue™.

EvolutionIsTrue™ is a mechanism that has evolved over about 100-150 years. Once there was this bloke named Charlie Darwin, and he imagined that living creatures evolved from one another, and he wrote a very boring book about it. He didn't really have a clue how it would work, because science kinda sucked back then. Many people said he was bonkers, but others took him seriously. Several decades later, science stopped sucking so much, and it became obvious that this evolution thing couldn't work. But some people liked Charlie's idea so much that, instead of disposing of it safely, they decided to promote it even more, despite the evidence. That was the foundation for EvolutionIsTrue™.

Microscope 1

Immune cells found to count interaction time to identify foreign proteins

T-cell immune system
© NIAID
The white blood cells called T-lymphocytes, such as this one shown by scanning electron microscopy, have receptors that bind to specific molecular targets. New work shows that the duration of this binding is what allows the cells to distinguish between the body's own proteins and those of invading pathogens.
Immunologists confirm an old hunch: T-cells identify what belongs in the body by timing how long they can bind to it.

To mount a successful defense against invading organisms, the immune system must quickly and accurately identify which cells belong in the body and which do not. That might seem straightforward enough, but it's not such an easy feat to achieve. The responsibility falls largely on the shoulders of T-cells, white blood cells with specialized receptors embedded in their surface that allow them to bind uniquely to diverse peptide fragments. Once bound, the T-cells can then initiate a focused attack against the target.

"It's an amazing needle in a haystack that they're trying to identify," said Orion Weiner, a biochemist at the University of California, San Francisco. "Being able to find that incredibly rare [foreign] peptide in a sea of quite similar self-peptides is an amazing challenge. It requires a degree of both specificity and sensitivity that's really at the limits of what's physically possible."

Dollars

Research suggests people are more honest than economic theory would have us believe

Lost Wallet
© Snap Decision / Getty Image
Frustrating, but research suggests lost wallets often aren’t a lost cause.
An international experiment involving over 17,000 lost wallets has revealed that humans are far more honest and altruistic than anyone, including professional economists, had ever imagined.

The research, published in the journal Science, shows that our sense of self and the desire to help others are sometimes more powerful than self-interest.

The Scottish philosopher Adam Smith placed self-interest at the heart of human behaviour in his 1776 work The Wealth of Nations.

Classical economics still holds that rational self-interest is the key to economic activity and will, as a by-product, generate social benefits; but such assumptions don't always lead to accurate predictions about human behaviour.

Alain Cohn and Christian Lukas Zünd of the University of Michigan, in the US, Michel André Maréchal of the University of Zurich, in Switzerland, and David Tannenbaum, of the University of Utah, Salt Lake City, in the US have carried out a series of studies that show self-interest is only part of the picture.

The team set out to see if "people act more dishonestly when they have a greater economic incentive to do so". This is the prediction from classic economic models based on rational self-interest, which "suggest that, all else equal, honest behaviour will become less common as the material incentives for dishonesty increase".

Our understanding of honesty, up until now, has largely come from laboratory work, but exactly how these results translate to real world activity has been far from clear.

Black Cat 2

'Cat-fox' identified as new species following DNA analysis in Corsica

cat-fox

There are just 16 of the cat-fox that look very similar to domestic cats
A new species which resembles an large domestic cat has been identified on the Mediterranean island of Corsica, experts said.

The animal is known locally as a "cat-fox".

It has wider ears, short whiskers and "highly developed canine teeth" compared to domestic felines.

Just 16 of the animals roam the small island, so efforts are being made to make them a protected species.

Comment: See also: Cat cognition: Cats rival dogs on many tests of social smarts. But is anyone brave enough to study them


Info

DNA may have emerged on Earth 4 billion years ago

DNA, the hereditary material, may have appeared on Earth earlier than has been assumed hitherto. LMU chemists led by Oliver Trapp show that a simple reaction pathway could have given rise to DNA subunits on the early Earth.
View of DNA
© Research Gate
View of a DNA fragment (CGTTTAAAGC) for (a) standard all-atom representation of the double helix and (b) the proposed coarse-grained model (12CG) based on 12 united atoms (grains) per base pair.
How were the building-blocks of life first formed on the early Earth? As yet, only partially satisfactory answers to this question are available. However, one thing is clear: The process of biological evolution that has given rise to the diversity of life on our planet must have been preceded by a phase of chemical evolution. During this 'prebiotic' stage, the first polymeric molecules capable of storing information and reproducing themselves were randomly assembled from organic precursors that were available on the early Earth. The most efficient replicators subsequently evolved into the macromolecular informational nucleic acids - DNA and RNA - that became the basis for all forms of life on our planet.

For billions of years, DNA has been the primary carrier of hereditary information in biological organisms. DNA strands are made up of four types of chemical subunits, and the genetic information it contains is encoded in the linear sequence of these 'nucleosides'. Moreover, the four subunits comprise two complementary pairs. Interactions between two strands with complementary sequences are responsible for the formation of the famous double helix, and play a crucial role in DNA replication. RNA also has vital functions in the replication of DNA and in the translation of nucleotide sequences into proteins.

Microscope 2

The secret life of viruses: Communication, cooperation

viruses
© Karol Banach
Geneticist Rotem Sorek could see that his bacteria were sick - so far, so good. He had deliberately infected them with a virus to test whether each ailing microbe soldiered on alone or communicated with its allies to fight the attack.

But when he and his team at the Weizmann Institute of Science in Rehovot, Israel, looked into the contents of their flasks, they saw something completely unexpected: the bacteria were silent, and it was the viruses that were chattering away, passing notes to each other in a molecular language only they could understand. They were deciding together when to lie low in the host cell and when to replicate and burst out, in search of new victims.

It was an accidental discovery that would fundamentally change scientists' understanding of how viruses behave.

Viruses that infect bacteria - spiky lollipop-like creatures known as bacteriophages (or phages) - have surveillance mechanisms that bring them intel on whether to stay dormant or attack, depending on the availability of fresh victims. But researchers long thought these processes were passive; the phages seemed to just sit back and listen in, waiting for bacterial distress signals to reach fever pitch before taking action.

Sorek and his colleagues had found phages actively discussing their choices. They realized that as a phage infects a cell, it releases a tiny protein - a peptide just six amino acids long - that serves as a message to its brethren: "I've taken a victim". As the phages infect more cells, the message gets louder, signalling that uninfected hosts are becoming scarce. Phages then put a halt to lysis - the process of replicating and breaking out of their hosts - instead staying hidden in a sluggish state called lysogeny1.

Ambulance

Cleveland Clinic surgeons perform first in-utero fetal surgery

surgeons

Amanda Kalan, M.D., (left) and Darrell Cass, M.D., (right) perform in utero spina bifida surgery.
Cleveland Clinic has successfully performed its first in utero fetal surgery to repair a spina bifida birth defect in a nearly 23-week-old fetus.

A multispecialty team of clinicians performed the surgery in February, and the baby, a girl, was later delivered by caesarean section near full term June 3, making it northern Ohio's first surgery of its kind. Mother and daughter are doing well.

The surgical team, led by Darrell Cass, M.D., director of Fetal Surgery in Cleveland Clinic's Fetal Center and a specialist who has performed more than 160 fetal surgeries since 2002, included Amanda Kalan, M.D., medical director of Cleveland Clinic's Special Delivery Unit; Violette Recinos, M.D., and Kaine Onwuzulike, M.D., both pediatric neurosurgeons; Francine Erenberg, M.D., fetal cardiologist; and McCallum Hoyt, M.D. and Tara Hata, M.D., obstetric and pediatric anesthesiologists.

Spina bifida is a birth defect that is most often discovered during the routine anatomy scan typically performed when a fetus is around 18 weeks old. The condition affects the lowest part of the spine and occurs when the neural tube does not fully close, causing the backbone that protects the spinal cord not to form as it should. This often results in damage to the spinal cord and nerves and can even lead to brain damage.

Cell Phone

Facebook posts could help doctors spot alcoholism, diabetes or depression, study says

Facebook phone
© NurPhoto/Getty Images
Is Facebook your new doctor?
As time consuming as Facebook can be sometimes, a new study suggests what you post could offer a window into your health. The language used in Facebook posts could be helpful in predicting diseases and mental health disorders, according to research from Penn Medicine and Stony Brook University. The study, published Monday in the journal PLOS ONE, suggested that social media posts could be monitored like physical symptoms.

Researchers found that the use of the words "drink" and "bottle" were predictive of alcohol abuse. While that one might seem obvious, the study also found that people who most often mentioned "God" and "pray" were 15 times more likely to have diabetes than those who used them less.

For some medical conditions, predictions based on Facebook posts were "significantly more accurate" than those from demographics alone, the study found. However, Facebook and demographic information combined were more accurate at predicting conditions than just social media posts alone.

Better Earth

The first people to arrive in Australia came in large numbers, and on purpose

Australia beach
© Rik Soderlund
An incredible journey: the first people to arrive in Australia came in large numbers, and on purpose
The size of the first population of people needed to arrive, survive, and thrive in what is now Australia is revealed in two studies published today.

It took more than 1,000 people to form a viable population. But this was no accidental migration, as our work shows the first arrivals must have been planned.

Our data suggest the ancestors of the Aboriginal, Torres Strait Islander, and Melanesian peoples first made it to Australia as part of an organised, technologically advanced migration to start a new life.

Changing coastlines

The continent of Australia that the first arrivals encountered wasn't what we know as Australia today. Instead, New Guinea, mainland Australia, and Tasmania were joined and formed a mega-continent referred to as Sahul.

Comment: See also:


Alarm Clock

Mars has a dust cycle just like Earth has a water cycle

mars dust
To say there are some myths circulating about Martian dust storms would be an understatement. Mars is known for its globe-encircling dust storms, the likes of which are seen nowhere else. Science fiction writers and Hollywood movies often make the dust storms out to be more dangerous than they really are. In "The Martian," a powerful dust storm destroys equipment, strands Matt Damon on Mars, and forces him into a brutal struggle for survival.

In reality-though global dust storms are a true spectacle, and winds can reach speeds of nearly 100 kph (60mph)-they're not violent. 100 kph is half the speed of some hurricanes here on Earth. Also, the Martian atmosphere is far less dense than Earth's atmosphere, so even the most powerful storms couldn't destroy any major equipment. You might not even be able to fly a kite.

But the dust storms on Mars are important to understand, and they can have consequences. The Opportunity rover was felled by a global dust storm that overwhelmed it. And any future human presence on Mars will have to take Martian dust storms into account.

Comment: It's not only Mars' dust storms that are cyclical in nature, a recent study revealed Mars' water vapor - like Earth's - also behaves in a cyclical manner too. This correlation is likely because they share a similar driver, the sun and it's solar cycles - and perhaps these are tied to even greater cycles which have yet to be discovered: