DEAR MAYO CLINIC: I have read that COVID-19 spreads from person to person, but can it also live on objects? Should I be concerned about catching the virus from things I buy at the grocery store or while filling up my car ...
Mar 23, 2020
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New research, published today in Nature, reveals how increasing brain stiffness as we age causes brain stem cell dysfunction, and demonstrates new ways to reverse older stem cells to a younger, healthier state.
Aug 14, 2019
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Fever is known to help power up our immune cells, and scientists in Shanghai have new evidence explaining how. They found in mice that fever alters surface proteins on immune cells like lymphocytes to make them better able ...
Jan 15, 2019
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With millions of COVID-19 cases reported across the globe, people are turning to antibody tests to find out whether they have been exposed to the coronavirus that causes the disease. But what are antibodies? Why are they ...
May 13, 2020
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Scientists in Japan have created a microscopically thin film that can coat individual teeth to prevent decay or to make them appear whiter, the chief researcher said.
Sep 16, 2012
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The virus that causes coronavirus disease 2019 (COVID-19) is stable for several hours to days in aerosols and on surfaces, according to a new study from National Institutes of Health, CDC, UCLA and Princeton University scientists ...
Mar 17, 2020
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It turns out undigested collagen blocking growing gland cells might sometimes be causing the blackheads seen in common acne, not just excess sebum, as had long been assumed. After the publication of a 2018 paper, researchers ...
Mar 19, 2019
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The new coronavirus can live in the air for several hours and on some surfaces for as long as two to three days, tests by U.S. government and other scientists have found.
Mar 12, 2020
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A review article summarizes everything that researchers know about the lifetime of corona viruses on surfaces and the effect of disinfectants.
Feb 7, 2020
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Rabies virus is incurable and almost always fatal once it has invaded the central nervous system, with the victim doomed to suffer a horrible death.
Sep 28, 2023
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In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball or bagel. On the other hand, there are surfaces which cannot be embedded in three-dimensional Euclidean space without introducing singularities or intersecting itself — these are the unorientable surfaces.
To say that a surface is "two-dimensional" means that, about each point, there is a coordinate patch on which a two-dimensional coordinate system is defined. For example, the surface of the Earth is (ideally) a two-dimensional sphere, and latitude and longitude provide coordinates on it — except at the International Date Line and the poles, where longitude is undefined. This example illustrates that not all surfaces admits a single coordinate patch. In general, multiple coordinate patches are needed to cover a surface.
Surfaces find application in physics, engineering, computer graphics, and many other disciplines, primarily when they represent the surfaces of physical objects. For example, in analyzing the aerodynamic properties of an airplane, the central consideration is the flow of air along its surface.
This text uses material from Wikipedia, licensed under CC BY-SA
