ravenword's New Writeups

Rett's syndrome (thing)

2005-07-12T01:27:40Z

Overview
Discovered by Austrian doctor Andreas Rett, Rett syndrome is a genetic pervasive developmental disorder in the autism spectrum.

Rett syndrome is the most prevalent cause of serious mental retardation in girls. Incidence rates are thought to be between 1 in 10,000 and 1 in 15,000 live female births.

Causes
The disorder is caused by a mutation on the MECP2 gene on the long leg of the X chromosome. Because the disorder is X-linked, boys carrying the trait (with only a single, mutant X chromosome) rarely survive past infancy, and the disorder is commonly observed only in girls.

The protein coded by a normal MECP2 gene binds to methylated DNA and acts as a transcription repressor (i.e., it "turns off" certain genes). It is not known which specific genes are repressed by MECP2, but it is safe to assume that the symptoms of Rett syndrom are…

synaptic scaling (idea)

2004-11-21T21:37:44Z

In studying learning and memory, neuroscientists are concerned with the interactions between neurons that occur at synapses. To grossly oversimplify a vast topic, one major way in which learning and memory can occur is by increasing synaptic strength. Consider any pair of neurons, one pre-synaptic and one post-synaptic. In order for a signal to pass between them, the pre-synaptic cell must fire an action potential and release neurotransmitters into the synaptic cleft between the two neurons. These transmitters, in turn, produce an effect on the post-synaptic cell's membrane potential called a post-synaptic potential, which can be either excitatory or inhibitory (EPSP versus IPSP). If the excitatory effect is great enough, then the post-synaptic cell will become depolarized to the extent that it, too, will produce an action potential, allowing the electrochemical signal to propagate.

Research done on…

Parasite Rex (thing)

2004-11-20T20:29:50Z

This book by notable popular science author Carl Zimmer details the primarily unseen world of parasites. Beginning with a discussion of why parasitism inspires such universal fascination and revulsion, and concluding with a slightly reaching analogy describing human beings as pests leeching off the Earth, Zimmer covers a wide range of topics within parasitology, biology, and evolution.

Zimmer has obviously performed extensive research on his subject, which the reader can duplicate with the aid of his helpful selected bibliography. He relates case studies of many specific parasite species, from the well known Plasmodium which causes malaria by infecting human red blood cells, to the parasitic barnacle of genus Sacculina, which invades the body of a crab, sterilizes it, and alters the host's behavior such that the infected crab actually nurtures the barnacle's eggs instead of its own -- even if…

miniskirt (thing)

2003-07-14T01:07:35Z

Some say that when fashionable skirt hemlines go up, so do stock prices. The popularity of the miniskirt is not dependent on the economy, however, but on the fact that it shows off a lot of leg. Who would argue against it?

The mini is a skirt whose hem falls noticeably above the knee. Fashion historians (apparently they exist) credit designers Mary Quant and Andre Courrèges both when naming the "inventors" of the miniskirt. Really, some girls were wearing them already, the designers just noticed and popularized them in the 1960s. Quant sold minis at her popular London boutique, and Courrèges adopted the short skirt as part of the "Mod" look that he created with his designs. Soon, minis were an international fashion craze, so popular in fact that they caused a revision of British tax law -- skirts were formerly taxed by length, but under that system minis were tax-exempt, and so changes…

Spouting Horn (place)

2003-07-08T18:57:24Z

The Spouting Horn is a natural lava formation that puts on a dramatic show. When the Pacific Ocean waves break against the lava shelf, water is forced through a hole in the rock and high into the air, like a geyser. Another hole in the lava nearby creates a hissing or moaning sound as air is forced through it. Together they form a popular tourist attraction on the Hawaiian island of Kauai, on the south shore about halfway between the cities of Po'ipu and Lawa'i.

Hawaiians have a legend about the Spouting Horn. The story says that the coastline was once guarded by a fierce giant lizard called Kaikapu who would eat anyone who tried to go fishing or swimming on her beach. One day, a clever fisherman named Liko came to the beach and was attacked by the lizard. She chased him down the shore and into the water, where he swam under the lava shelf through a lava tube. She followed, but he…

boontling (idea)

2003-07-06T21:22:18Z

Constructed languages often seem to be an impractical fancy of (pseudo)intellectuals and/or nerds. After all, Esperanto, perhaps the most famous planned language, is not exactly popular with the man on the street, and let's not even get started on people who speak Klingon. Trying to imagine a created language often brings up images, too, of Tolkien immersed in his Elvish tongues, seemingly detached from reality. However, Boontling represents a constructed dialect invented by the common man, or rather, woman: its origins can be traced back to women working in a hops field, coming up with slang to use for sharing secret gossip.

Boontling was invented around 1880 in the Anderson Valley town of Boonville, California, and flourished for about 40 years. Some residents of the area used Boontling as their primary language, and had difficulty with standard English when required to speak…