Archive for the ‘Uncategorized’ Category
COVID vaccines and blood clots: five key questions
It has been a difficult week for two COVID-19 vaccines. On 13 April, US regulators urged health-care providers to temporarily stop using a vaccine made by Johnson & Johnson (J&J) of New Brunswick, New Jersey, because of six suspected cases of unusual blood clotting among nearly seven million vaccine recipients. The move came after European regulators expressed concerns about a possible link between rare blood clots and the Oxford–AstraZeneca vaccine, developed in the United Kingdom by AstraZeneca in Cambridge and the University of Oxford …. Read more at www.nature.com
The Forgotten Life of Mileva Marić Einstein
Mileva Mari´c Einstein and her husband, Albert Einstein in 1912.
Pauline Gagnon
Today, February 11, is the International Day of Women and Girls in Science, the perfect day to remember Mileva Marić Einstein, a brilliant but largely unknown scientist. While her husband, Albert Einstein is celebrated as perhaps the best physicist of the century, one question about his career remains: How much did his first wife contribute to his groundbreaking science? While it is not possible to credit her with any specific part of his work, their letters and numerous testimonies presented in books dedicated to her [1−5] provide substantial evidence on how they collaborated from the time they met in 1896 up to their separation in 1914. They depict a couple united by a shared passion for physics, music and for each other. So here is her story.
Read more at https://arxiv.org/pdf/2002.08888.pdf
State of the art in magnetic resonance imaging
As a clinical technology, MRI offers unsurpassed flexibility to look inside the human body.
In 1977, inspired by the observation that cancerous and healthy tissues produced different nuclear magnetic resonance signals, Raymond Damadian, Michael Goldsmith, and Lawrence Minkoff performed the first MRI scan of a live human body. In the early days of clinical MRI, scans took hours and provided low spatial resolution, but they have become essential for distinguishing between healthy and diseased tissues. By its 40th anniversary, MRI was a must-have tool in hospitals and clinics of all sizes. And it has found applications in image-guided interventions and surgeries, radiation therapy, and focused ultrasound. Advances in technology, meanwhile, have pushed the envelope of scanner performance with improvements to speed and spatial resolution.
At the frontiers of MRI development, work is focused on fast, quantitative imaging. Clinical needs increasingly demand functional information—on heart-muscle contractions, brain activity,3 chemical concentrations in tumors,4 and blood flow in and out of tissue5—in addition to anatomical structures. New approaches must also maintain a patient’s comfort and safety; MRI is well-known for sparing patients any exposure to ionizing radiation, yet it is not without hazards.
HOW MRI WORKS
SPATIAL ENCODING
Read more at https://physicstoday.scitation.org/doi/10.1063/PT.3.4408
A quick how-to user-guide to debunking pseudoscientific claims
Maxim Sukharev
Have you ever wondered why we have never heard of psychics and palm readers winning millions of dollars in state or local lotteries or becoming Wall Street wolfs? Neither have I. Yet we are constantly bombarded by tabloid news on how vaccines cause autism (hint: they do not), or some unknown firm building a mega-drive that defies the laws of physics (nope, that drive does not work either). And the list continues on and on and on. Sometimes it looks quite legit as, say, various natural vitamin supplements that supposedly increase something that cannot be increased, or enhance something else that is most likely impossible to enhance by simply swallowing a few pills. Or constantly evolving diets that sure work giving a false relieve to those who really need to stop eating too much and actually pay frequent visits to a local gym. It is however understandable that most of us fall for such products and news just because we cannot be experts in everything, and we tend to trust various mass-media sources without even a glimpse of skepticism. So how can we distinguish between baloney statements and real exciting scientific discoveries and breakthroughs? In what follows I will try to do my best to provide a simple how-to user guide to debunking pseudoscientific claims.
Read more at https://arxiv.org/ftp/arxiv/papers/1906/1906.06165.pdf
Edward Witten
The Heidelberg Laureate Forum Foundation presents the HLF Portraits: Edward Witten
Einstein’s biggest mistake?
Gary J. Ferland
What, if any, was Einstein’s biggest mistake, the one most affecting our physics today? There is a perhaps apocryphal story, recounted by George Gamow, that he counted his cosmological constant as his biggest blunder. We now know his hypothesized cosmological constant to be correct. His lifelong rejection of quantum mechanics, an interesting side-story in the evolution of 20th-century physics, is a candidate. None of these introduced difficulties in how our physics is done today. It can be argued that his biggest actual mistake, one that affects many subfields of physics and chemistry and bewilders students today, occurred in his naming of his A and B coefficients…
Read more at https://arxiv.org/pdf/1905.09276.pdf
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