Wednesday, November 19, 2008

Early aeronautics

Before scientific investigation of aeronautics started, people started thinking of ways to fly. In a Greek legend, Icarus and his father Daedalus built wings of feathers and wax and flew out of a prison. Icarus flew too close to the sun, the wax melted, and he fell in the sea and drowned. When people started to scientifically study how to fly, people began to understand the basics of air and aerodynamics. One of the earliest scientists to study aeronautics was Leonardo da Vinci.

Leonardo studied the flight of birds in developing engineering schematics for some of the earliest flying machines in the late fifteenth century AD. His schematics, however, such as the ornithopter ultimately failed as practical aircraft. The flapping machines that he designed were either too small to generate sufficient lift, or too heavy for a human to operate. Although the ornithopter continues to be of interest to hobbyists, it was replaced by the glider in the 19th century.

Wednesday, November 12, 2008

Cardiac Arrest

The heart has an internal electrical system that controls the rhythm of the heartbeat. Problems can cause abnormal heart rhythms, called arrhythmias. There are many types of arrhythmia. During an arrhythmia, the heart can beat too fast, too slow, or it can stop beating. Sudden cardiac arrest occurs when the heart develops an arrhythmia that causes it to stop beating. This is different than a heart attack, where the heart usually continues to beat but blood flow to the heart is blocked.

There are many possible causes of cardiac arrest. They include coronary heart disease, heart attack, electrocution, drowning, or choking. There may not be a known cause to the cardiac arrest.

Without medical attention, the person will die within a few minutes. People are less likely to die if they have early cardiopulmonary resuscitation (CPR) and defibrillation. Defibrillation is delivering an electric shock to restore the heart rhythm to normal.

Tuesday, November 04, 2008

Dogarutkay Flowers

A flower also recognized as a bloom or blossom, is the reproductive configuration establish in flowering plants. The flower's structure contains the plant's reproductive organs, and its role is to make seeds. After fertilization, portions of the flower build up into a fruit containing the seeds. For the high plants, seeds are the next production, and serve up as the primary means by which individuals of a variety are dispersed across the scenery. The grouping of flowers on a place is called the inflorescence.

Many flowers in natural world have evolved to magnetize animals to pollinate the flower, the actions of the pollinating means contributing to the chance for genetic recombination within a dispersed plant population. Flowers commonly have glands called nectarines on their various parts that attract these birds.