Scientists Created Male and Female Cells from a Single Person

Most people have two sex chromosomes, either two X’s or an X and a Y, which give rise to female or male biological attributes on a spectrum. Studies suggest these chromosomes also have much broader effects, contributing to processes that include immune system function, neuronal development, disease susceptibility and reactions to drugs. But scrutinizing the specific role of X and Y chromosomes is challenging. With current tools, it is difficult to disentangle the effects of genes versus hormones, for example.

Now scientists have devised a tool that could overcome this obstacle—by generating XX and XY cells from a single person for the first time. This unique set of cells could help researchers tackle long-standing questions about how sex chromosomes affect disease and the role they play in early development.

— source | Dec 21, 2022

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Extinct ‘monkey lemur’ shows similarities to fossil humans

Analysis of teeth of extinct lemurs has revealed fascinating clues to the evolution of humans, a University of Otago study has found. monkey lemur, Archaeolemur, had novel anatomical features not seen in living lemurs, such as lacking a ‘tooth comb’ in the front of the mouth for grooming. The study, published in the American Journal of Biological Anthropology, aimed to assess the diet of Archaeolemur by analysing chipping in 447 teeth, comparing chipping frequencies to those of other primates. The results were surprising — with these remarkable extinct lemurs with dentitions resembling baboons in shape; but presenting tooth chipping patterns similar to fossil hominins such as Neanderthals.

— source University of Otago | Dec 12, 2022

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Measuring times in billionths of a billionth of a second

Scientists have developed a novel interferometric technique capable of measuring time delays with zeptosecond (a trillionth of a billionth of a second) resolution. They have used this technique to measure the time delay between extreme ultraviolet light pulses emitted by two different isotopes of hydrogen molecules — H2 and D2 — interacting with intense infrared laser pulses. This delay was found to be less than three attoseconds (one quintillionth of a second long) and is caused by slightly different motions of the lighter and heavier nuclei. Scientists at the Australian Attosecond Science Facility and the Centre for Quantum Dynamics of Griffith University in Brisbane Australia have developed this.

— source | Dec 5, 2022

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What Is Math?

It all started with an innocuous TikTok video posted by a high school student named Gracie Cunningham. Applying make-up while speaking into the camera, the teenager questioned whether math is “real.” She added: “I know it’s real, because we all learn it in school… but who came up with this concept?” Pythagoras, she muses, “didn’t even have plumbing—and he was like, ‘Let me worry about y = mx + b’”—referring to the equation describing a straight line on a two-dimensional plane. She wondered where it all came from. “I get addition,” she said, “but how would you come up with the concept of algebra? What would you need it for?”

Someone re-posted the video to Twitter, where it soon went viral. Many of the comments were unkind: One person said it was the “dumbest video” they had ever seen; others suggested it was indicative of a failed education system. Others, meanwhile, came to Cunningham’s defense, saying that her questions were actually rather profound.


this video makes sense in my head but like WHY DID WE CREATE THIS STUFF
♬ original sound – gracie

Mathematicians from Cornell and from the University of Wisconsin weighed in, as did philosopher Philip Goff of Durham University in the U.K. Mathematician Eugenia Cheng, currently the scientist-in-residence at the Art Institute of Chicago, wrote a two-page reply and said Cunningham had raised profound questions about the nature of mathematics “in a very deeply probing way.”

Cunningham had unwittingly re-ignited a very ancient and unresolved debate in the philosophy of science. What, exactly, is math? Is it invented, or discovered? And are the things

— source | Dan Falk | Sep 23, 2020

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Einstein’s Greatest Theory Just Passed Its Most Rigorous Test Yet

Scientists have demonstrated that Einstein’s theory of general relativity is correct to a remarkable degree of accuracy, despite having been around for more than a century. The team behind the research wanted to test a component of Einstein’s theory of general relativity called the weak equivalence principle, which states that all objects, regardless of their mass or composition, should free-fall the same way in a particular gravitational field when interference from factors like air pressure is eliminated.

One of the most famous tests of the weak equivalence principe occurred during an Apollo 15 moonwalk, when astronaut David Scott dropped a feather and a geological hammer at the same time; without air resistance, both objects accelerated toward the moon’s surface at the same rate.

To do so, the scientists measured the acceleration of free-falling objects in a French satellite called MICROSCOPE, which launched in 2016. The team’s results, which are the culmination of 20 years of research, revealed that acceleration in pairs of objects in free fall differed by no more than 1 part in 10^15, or 0.000000000000001, meaning they found no violations in the weak equivalence principle larger than that.

— source | Sep 15, 2022

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What is scientific consensus

You’ll most likely have seen instances where the term “scientific consensus” has been misused or misunderstood. People for example often confuse it with appeals to popular opinion or think it is the result of discussions or determined by a vote or just finding a compromise. Because of this, opinion polls – even if predominated by unqualified individuals – are used to argue that no scientific consensus exists for a particular topic even if it clearly does.

It’s important to note that a scientific consensus is not proof for a scientific theory but that it’s the result of converging lines of evidence all pointing to the same conclusion. It is therefore not a part of the scientific method but is actually a consequence of it. When people argue against a scientific consensus, they are usually

— source | BaerbelW | 30 Nov 2022

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The Myth of Normal

the pandemic actually revealed to us how toxic our idea of normal has been, because it showed us the desperate need for human connection that we all have. But this is in a culture that has been isolating and atomizing individuals for a long time, where loneliness has been an epidemic for decades. It showed the noxious effect of racism and inequality, because the people who had the greatest risk for being affected by COVID were those of a lower social class and of people of color.

The normal that we came from, in my perspective, was already a toxic normal. We don’t want to go back to it, because my contention in this book is what we consider to be normal in this society is actually neither natural or healthy, and, in fact, it’s a cause of much human pathology, mental and physical. And actually, people’s pathologies, what we call abnormalities, whether it’s mental or physical illness, are actually normal responses to what is an abnormal culture.

the key here is trauma. Trauma is a psychological wound that people sustain. And I’m saying that in this society, most of us, because of the nature of the culture, the way we raise children, the way we have to relate to each other, the very values of a society are traumatizing for a lot of people, so that it’s false to say that some people are normal and others are abnormal. In fact, we’re all on a spectrum of woundedness, which has great impact on how we relate to each other and on our health.

— source | Sep 16, 2022

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The Neandertal in Our Genes

Scientists have always been fascinated by the question of human origins: When and where did modern humans—Homo sapiens—first appear? What distinguishes us from other members of the genus Homo and enabled us to develop such unprecedented culture and society?

Indeed, hardly any question fascinates humanity as much as our own roots. For thousands of years, clerics, scholars and philosophers have been racking their brains about where we come from, who are we and where are we going. The French painter Paul Gauguin was so captivated by that line of inquiry that he even dedicated a painting so named in the 19th century. The work, which deals with both the meaning and the transience of life, remains his most famous.

We have come a lot closer to answering these big questions thanks in part to the work of the paleogeneticist Svante Pääbo. He achieved what others had long thought impossible: he decoded the genome of Neandertals, a relative of modern humans who went extinct around 30,000 years ago. The Nobel Assembly at the Karolinska Institute in Stockholm honored him

— source | Daniela Mocker | Oct 4, 2022

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