ScienceIQ.com

The Hydrology of Drought

A drought is a period of drier-than-normal conditions that results in water-related problems. Precipitation (rain or snow) falls in uneven patterns across the country. The amount of precipitation at a particular location varies from year to year, but over a period of years, the average amount is fairly constant. In the deserts of the Southwest, the ...

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TheHydrologyofDrought
Astronomy

Right Ascension & Declination

Right Ascension (abbreviated R.A.) and Declination (abbreviated Dec) are a system of coordinates used by astronomers to keep track of where stars and galaxies are in the sky. They are similar to the ... Continue reading

RightAscensionDeclination
Biology

Wetlands Top Ecosystem

Wetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season. ... Continue reading

Wetlands
Engineering

It's A Bird, It's A Plane -- No, It's A Clam!

Not all animals glide or fly in the air. Many marine animals are masters of 'flight' and speed under the water. The ocean environment brings its own set of adaptations and specializations for the ... Continue reading

BirdClam
Physics

Carbon Dating From The Skies

Determining the age of relatively recent fossils, those of plants and animals that lived tens of thousands of years ago, is not a guessing game but an exact science. By using carbon dating we can ... Continue reading

CarbonDatingFromTheSkies

Facts About Angina

FactsAboutAnginaAngina is a recurring pain or discomfort in the chest that happens when some part of the heart does not receive enough blood. It is a common symptom of coronary heart disease (CHD), which occurs when vessels that carry blood to the heart become narrowed and blocked due to atherosclerosis Angina feels like a pressing or squeezing pain, usually in the chest under the breast bone, but sometimes in the shoulders, arms, neck, jaws, or back. Angina is usually precipitated by exertion. It is usually relieved within a few minutes by resting or by taking prescribed angina medicine. Episodes of angina occur when the heart's need for oxygen increases beyond the oxygen available from the blood nourishing the heart. Physical exertion is the most common trigger for angina. Other triggers can be emotional stress, extreme cold or heat, heavy meals, alcohol, and cigarette smoking.

An episode of angina is not a heart attack. Angina pain means that some of the heart muscle in not getting enough blood temporarily--for example, during exercise, when the heart has to work harder. The pain does NOT mean that the heart muscle is suffering irreversible, permanent damage. Episodes of angina seldom cause permanent damage to heart muscle. In contrast, a heart attack occurs when the blood flow to a part of the heart is suddenly and permanently cut off. This causes permanent damage to the heart muscle. Typically, the chest pain is more severe, lasts longer, and does not go away with rest or with medicine that was previously effective. It may be accompanied by indigestion, nausea, weakness, and sweating. However, the symptoms of a heart attack are varied and may be considerably milder.

When someone has a repeating but stable pattern of angina, an episode of angina does not mean that a heart attack is about to happen. Angina means that there is underlying coronary heart disease. Patients with angina are at an increased risk of heart attack compared with those who have no symptoms of cardiovascular disease, but the episode of angina is not a signal that a heart attack is about to happen. In contrast, when the pattern of angina changes--if episodes become more frequent, last longer, or occur without exercise--the risk of heart attack in subsequent days or weeks is much higher.