ScienceIQ.com

An Invasion of Infiltrators

Why might a species be invasive in one country but not a big problem in its native land? As an example, consider a plant that is a major weed in the U.S. but in its native land it may be a minor pest. Many weeds have chemical defense systems that make them taste bad. In the weed's native land the animals that feed on the weed often evolve along ...

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Infiltrators
Geology

Under The Crust

Three centuries ago, the English scientist Isaac Newton calculated, from his studies of planets and the force of gravity, that the average density of the Earth is twice that of surface rocks and ... Continue reading

UnderTheCrust
Astronomy

Pluto: Beyond Neptune Or Not?

Did I catch you? Pluto (newly classified as a dwarf-planet) comes after planet Neptune. Right? Depends. Pluto takes 248 years to orbit the Sun. Most of that time Pluto's orbit puts it outside the ... Continue reading

Pluto
Chemistry

SO2: What is it? Where does it come from?

Sulfur dioxide, or SO2, belongs to the family of sulfur oxide gases (SOx). These gases dissolve easily in water. Sulfur is prevalent in all raw materials, including crude oil, coal, and ore that ... Continue reading

SO2
Biology

What are Bacillariophyta?

Bacillariophyta are diatoms. All diatoms are single-celled organisms. They are microscopic, glassy organisms that photosynthesize for food, like plants. Diatoms live in the sediments of freshwater, ... Continue reading

WhatareBacillariophyta

What is Headache?

WhatisHeadacheWhen a person has a headache, several areas of the head can hurt, including a network of nerves that extends over the scalp and certain nerves in the face, mouth, and throat. The muscles of the head and the blood vessels found along the surface and at the base of the brain are also sensitive to pain because they contain delicate nerve fibers. The bones of the skull and tissues of the brain itself never hurt because they lack pain-sensitive nerve fibers. The ends of these pain-sensitive nerves, called nociceptors, can be stimulated by stress, muscular tension, dilated blood vessels, and others triggers of headache.

Vascular headaches (migraines are a kind of vascular headache) are thought to involve abnormal function of the brain's blood vessels or vascular system; muscle contraction headaches appear to involve the tightening or tensing of facial and neck muscles; and traction and inflammatory headaches are symptoms of other disorders, ranging from brain tumor to stroke to sinus infection.

Some types of headache are signals of more serious disorders: sudden, severe headache; headache associated with convulsions; headache accompanied by confusion or loss of consciousness; headache following a blow on the head; headache associated with pain in the eye or ear; persistent headache in a person who was previously headache free; recurring headache in children; headache associated with fever; headache that interferes with normal life. Physicians will obtain a full medical history and may order a blood test to screen for thyroid disease, anemia, or infections or x-rays to rule out a brain tumor or blood clots. CTs, MRIs, and EEGs may be recommended. An eye exam is usually performed to check for weakness in the eye muscle or unequal pupil size. Some scientists believe that fatigue, glaring or flickering lights, the weather, and certain foods may trigger migraine headaches.