This Week's News
In order to better understand the mind of the milk cow, animal researchers at Purdue University had heifers walk through a Y-shaped maze. At the end of either branch of the Y was a person offering a nice pet, a shout, or food. Surprisingly enough, the cows highly preferred food over either alternative, the pet didn't garner much of a reponse, and a shout was enough to keep the cows away. This suggests that in order to have happy cows, cow farmers should always feed their cows and never shout at them, but don't need to bother much with petting them.
For all organisms, it is important to determine environmental temperatures. If it gets too cold or hot severe damage can occur to the body. So, many different mechanisms have evolved to solve the problem. In the case of mammals, changes in temperature cause channels to open in the cell membrane that allow the influx of electrically charged particles into the cell. This influx then initiates an electrical signal to the brain that conveys information about the temperature. A physics researcher at the University of San Francisco recently investigated the mechanism used by sharks and found that they have a semiconducting gel-like substance in their noses that conveys information about temperature. This substance gets better at conducting electricity the warmer it gets, and is highly sensitive even to changes as small as 0.1 degree Celcius. It is thought that this sensitivity might be what allows sharks to track small changes in water temperature. Read more
here or
here.
German researchers at the University of Konstanz have identified a prion in pufferfish. It is thought to be related to the infectious prion found in mammals that causes such diseases as mad-cow and Creutzfeldt-Jakobs (vCJD). Although the fish prion is different from the mammalian prion, researchers are determining whether the fish prion gene can be altered to become infectious to mice. If possible, it might point to particular locations within the mammalian prion gene that make it infectious and disease-causing. In addition, they are looking for companion genes to the fish prion that might help make it a prion. The trouble in all this is that it is very difficult to know whether the fish prion results in disease since it is very difficult to diagnose potential behavioral abnormalities in fish. Read more
here.
In the search to discover just how the sperm from males ever reaches a female's egg, researchers at the Weizmann Institute investigated the effects of temperature on swim direction of rabbit and human sperm. When the sperm were given a choice to make, the sperm travelled in the direction of warmer water. In fact, they preferred the water at a temperature slightly above body temperature, which is similar to the temperature near the fallopian tubes where an egg might be found. The researchers suggest that sperm use this temperature guidance system for the long-range targetting, but then use a chemically based search system for close-range. Read more
hereand
here.
Headline Links: Check these out for topics that weren't covered on this week's show!
Fetal tissue transplants improve adult sight (
New Scientist)
Chromosome study links telomere length to survival (
Reuters AlertNet, UK)
New research on exercise (
U. TV)
current science news posted by Kirsten at 2/04/2003 04:06:00 PM
Scientists
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