Diseases, Conditions, Syndromes

Wiping down groceries? Experts say keep risk in perspective

Cleaning wipes are harder to find on store shelves, and businesses are reassuring customers with stepped up sanitation measures. In New York, the subway system is shut down nightly for disinfecting.

Diseases, Conditions, Syndromes

A disinfection system that could neutralise COVID-19 in a few minutes

Cedrión, a company supported by the Universidad Carlos III de Madrid (UC3M), has designed a disinfection system that could neutralize COVID-19 in just over 10 minutes. The system uses atmospheric plasma to disinfect spaces ...

Health

Why you should clean the kitchen counter after preparing food

Food and humans can carry and spread dangerous microbes, and cleaning can protect you from getting sick. But it also takes time, uses chemicals and water and some people are concerned that excessive cleaning can remove the ...

Dentistry

Coating implants with 'artificial bone' to prevent inflammation

Bone disease is becoming increasingly prevalent due to population aging, among other factors, and the use of dental and orthopedic implants to treat bone disease has been on the rise. The history of implants can be traced ...

Diseases, Conditions, Syndromes

New research on SARS-CoV-2 virus 'survivability'

Researchers at CSIRO, Australia's national science agency, have found that SARS-CoV-2, the virus responsible for COVID-19, can survive for up to 28 days on common surfaces including banknotes, glass—such as that found on ...

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Surface

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