Education-Science

Mysterious Quantum Rule Reconstructed From Scratch

QuantaMagazine Phillip Ball 02/14/2019

Quantum mechanics became a strange kind of theory not with Werner Heisenberg’s famous uncertainty principle in 1927, nor when Albert Einstein and two colleagues identified (and Erwin Schrödinger named) entanglement in 1935. It happened in 1926, thanks to a proposal from the German physicist Max Born. Born suggested that the right way to interpret the wavy nature of quantum particles was as waves of probability. The wave equation presented by Schrödinger the previous year, Born said, was basically a piece of mathematical machinery for calculating the chances of observing a particular outcome in an experiment.

Neanderthals may have used their hands differently from humans

The Neanderthals did use their hands differently from us, a new study published Thursday in the journal Scientific Reports has suggested. Our archaic relatives, lead study author Bardo said, would have been more at ease with "squeeze grips" -- the grip we use when we hold tools with handles like a hammer.

Ancient stone tools hint at settlers’ epic trek to North America

16,000-year-old artefacts discovered in Idaho could be the oldest ever found on the continent.
The finds make the site, called Cooper’s Ferry, one of the oldest-known human settlements in North America, if not the oldest, says Loren Davis, an archaeologist at Oregon State University in Corvallis, who led the 10-year excavation that made the discoveries. His team’s results were published in Science on 29 August.

Pre-Clovis occupation of the Americas identified by human fecal biomarkers in coprolites from Paisley Caves, Oregon

Here, we use fecal lipid biomarkers to demonstrate unequivocally that three coprolites dated to pre-Clovis are human, raise questions over the reliance on DNA methods, and present a new radiocarbon date on basketry further supporting pre-Clovis human occupation.
It is largely, but not entirely, accepted by the archaeological community that people first settled the Americas before Clovis (1–3), which was seen as the earliest technological tradition on the continent for most of the 20th century, dating to 11,500 radiocarbon years before the present (14C yr B.P.) However, many questions still remain over who the earliest settlers were, when they arrived, and what route they took.

Ancient genomics is recasting the story of the Americas’ first residents

Trove of DNA from prehistoric inhabitants reveals that the continents’ early settlers moved far and fast.
Ancient genomics is finally beginning to tell the history of the Americas — and it’s looking messy.
The Montana baby, known as the Anzick boy, belonged to a population known as the Southern Native Americans, who are most closely related to present-day Indigenous populations from South America. They split from Northern Native Americans, who are genetically closer to many contemporary groups in eastern North America, around 14,600–17,500 years ago. The common ancestor of these two groups split from East Asians some 25,000 years ago, scientists established this year by sequencing the genome of 11,500-year-old human remains from Alaska5.

From chaos to free will

Since Laplace’s day, scientists, philosophers and even neuroscientists have followed his lead in denying the possibility of free will. This reflects a widespread belief among theoretical physicists that if you know the initial values of the variables that characterise a physical system, together with the equations that explain how these variables change over time, then you can calculate the state of the system at all later times........
One of the most astounding discoveries of the previous century was that biological activity at the micro level is literally grounded in the physical shape of biological molecules, particularly DNA, RNA and proteins. This discovery became possible only when X-ray crystallography had progressed to the point of allowing us to determine the extraordinarily complex detailed structure and foldings of these molecules...............................
Genuine mental functioning and the ability to make decisions in a rational way is a far more persuasive explanation of how books get written. That this is possible is due to the extraordinary hierarchical structure of our brain and its functioning. And that functioning is enabled by downward causation from the psychological to the physical levels, with outcomes at the physics level determined by constraints that change over time. No violation of physical laws need occur.................................

Physics has made huge strides since the days of Laplace; indeed, it would be completely unrecognisable to him. Yet there are still physicists today who confidently proclaim that we can’t have free will because physics determines everything, including brain functioning – entirely ignoring the complex context and the power of constraints............

If you seriously believe that fundamental forces leave no space for free will, then it’s impossible for us to genuinely make choices as moral beings. We wouldn’t be accountable in any meaningful way for our reactions to global climate change, child trafficking or viral pandemics. The underlying physics would in reality be governing our behaviour, and responsibility wouldn’t enter into the picture.

.............

That’s a devastating conclusion. We can be grateful it’s not true.

Early humans domesticated themselves, new genetic evidence suggests

Domestication encompasses a whole suite of genetic changes that arise as a species is bred to be friendlier and less aggressive. In dogs and domesticated foxes, for example, many changes are physical: smaller teeth and skulls, floppy ears, and shorter, curlier tails. Those physical changes have all been linked to the fact that domesticated animals have fewer of a certain type of stem cell, called neural crest stem cells.

Modern humans are also less aggressive and more cooperative than many of our ancestors. And we, too, exhibit a significant physical change: Though our brains are big, our skulls are smaller, and our brow ridges are less pronounced. So, did we domesticate ourselves?

Giuseppe Testa, a molecular biologist at University of Milan in Italy, and colleagues knew that one gene, BAZ1B, plays an important role in orchestrating the movements of neural crest cells. Most people have two copies of this gene. Curiously, one copy of BAZ1B, along with a handful of others, is missing in people with Williams-Beuren syndrome, a disorder linked to cognitive impairments, smaller skulls, elfinlike facial features, and extreme friendliness.

Newly Discovered Fossil Bird Fills in Gap Between Dinosaurs and Modern Fliers

The 120 million-year-old fossil was discovered in the summer of 2013 while searching for fossils at Japan’s Kitadani Dinosaur Quarry. “One of my colleagues at Fukui Prefectural Dinosaur Museum spotted tiny bones in a block of siltstone,” Imai says. At the time, it wasn’t clear what creature the bones belonged to, but once the encasing rock was chipped away, the structure of the fossil became clear. The skeleton was an early bird, and an unusual one at that.

Small bodies and hollow bones have made birds relatively rare finds in the fossil record. Only a few unique fossil deposits, like China’s 125 million-year-old Jehol Biota or the United States’ 50 million-year-old Green River Formation, allow paleontologists to get a good look at ancient avians. To find a well-preserved fossil bird outside such places of exceptional preservation represents a noteworthy paleontological discovery, and Fukuipteryx in Japan adds another significant spot on the map for fossil birds.

'Dragon teeth’ reveal ancient ape’s place in primate family tree

In 1935, anthropologist Gustav von Koenigswald came across several strange teeth in drug stores in Hong Kong and southern China. The specimens, sold as “dragon teeth,” to be ground up for use in Chinese medicine, were special: They were apelike, but huge—much bigger than the molars of any other fossil or living primates. Their size (and that of four fossilized jaw bones) suggested that Gigantopithecus blacki was the largest primate ever discovered, towering nearly 3 meters in height(9 feet). But without any skulls or skeletons, researchers didn’t know whether the animal, which lived from roughly 2 million to 200,000 years ago, was a relative of today’s orangutans, today’s African apes, or something else entirely.

Frido Welker, an evolutionary geneticist at the University of Copenhagen, and his colleagues set out to examine G. blacki teeth for intact pieces of proteins called peptides, which may be preserved for up to a few million years—far longer than more fragile DNA. Welker and his colleagues dissolved tiny amounts of enamel from a G. blacki molar and used mass spectrometry to identify more than 500 peptides that matched six proteins. By comparing the amino acids to those in the same six proteins in living apes, including orangutans, gorillas, and other apes and monkeys, they calculated that the giant ape was most closely related to orangutans. The two lineages probably split off between 10 million and 12 million years ago, they report today in Nature.

Is Evolution Predictable? Important Implications for the Way We Understand Life on Earth

“Our team is the first to report that although evolution of similar color patterns in Heliconius may be driven by similar forces–like predators avoiding a particular kind of butterfly–the pathway to that outcome is not predictable,” said Carolina Concha, lead author of the paper and a post-doctoral fellow at STRI. “This really surprised us because it reveals the importance of history and chance in shaping the genetic pathways leading to butterfly wing-pattern mimicry.”

Heliconius‘ bright wing colors signal to bird predators that the butterflies are toxic. Flashy male wing patterns signal to females that they are choosing the right species to mate with. Somehow these two forces, predation and mating, lead to similar wing patterns in groups of butterflies isolated in the mountain valleys and foothills of the Andes. By knocking out a single gene called WntA in 12 different species and their variants, the molecular biologists on the team could tell whether the butterflies in a pair with the same wing patterns were using the same genetic pathways to color and pattern their wings. They were not.

Education-Science

Contents

Mysterious Quantum Rule Reconstructed From Scratch

Neanderthals may have used their hands differently from humans

Ancient stone tools hint at settlers’ epic trek to North America

Pre-Clovis occupation of the Americas identified by human fecal biomarkers in coprolites from Paisley Caves, Oregon

Ancient genomics is recasting the story of the Americas’ first residents

From chaos to free will

Early humans domesticated themselves, new genetic evidence suggests

Newly Discovered Fossil Bird Fills in Gap Between Dinosaurs and Modern Fliers

'Dragon teeth’ reveal ancient ape’s place in primate family tree

Is Evolution Predictable? Important Implications for the Way We Understand Life on Earth

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