banner1

Main Menu
Home
News
Links
Wiki
Search
Administrator
FAQ
Contact Us
Science Books
Register
Online Store
Science on the Web
Store - beta
Project Fork
Feature Sections
Encyclopedia Astronuc
ID Watch
Community Menu
Forum
Einstein@Home
Member Blogs
Science Social Network
Science Network Users
Login Form
Welcome, Guest. Please login or register.
March 16, 2010, 01:34:53 AM
Username: Password:
Login with username, password and session length

Password reminder
Did you know?

The Platypus is stranger than you think.

Platypuses have no nipples.  After the young hatch, the mother oozes milk from the pores all over her body.

The male platypus has a poison barb on the inside of its hind legs.  The purpose of this weapon is uncertain.

While often compared to the beaver, the platypus is only about 20 inches in length -- more comparable to the size of the muskrat.

The Platypus bill is actually just an elongated muzzle covered with much the same kind of tough skin found on a dog's nose.  This bill contains an electrically-sensitive organ that can detect the electrical signatures of the small aquatic animals it eats.

(0) Comments posted about this in the forum
Statistics
Members: 2782
News: 257
Web Links: 34
Welcome to Everything Science
Snapdragons take the evolutionary high-road PDF Print
User Rating: / 6
Everything Biology
Written by Everything Science   
Aug 21, 2006 at 12:00 AM
Roses are red, violets are blue, but why aren't snapdragons orange? Norwich scientists from the John Innes Centre (JIC) and the University of East Anglia (UEA) in collaboration with the Universitïé Paul Sabatier (Toulouse, France) have developed a pioneering computer modelling technique that traces the evolutionary paths underlying flower colour variation in the model plant snapdragon (Antirrhinum).Their research, funded by the BBSRC and published today in the journal Science, shows how flower colour diversity has evolved in natural populations of these plants in the Pyrenees.

bee_magenta

Bees that pollinate snapdragons prefer magenta or yellow coloured flowers to flower colours such as orange. (Photo taken by Annabel Whibley)

In the wild, only the plants with the most attractive flower colours are able to reproduce and thrive because the insects that pollinate them prefer certain colours. The bees that pollinate snapdragon find magenta and yellow flowers the most attractive; they do not find colours such as orange attractive and so flowers of this colour would not flourish in the wild due to lack of pollination. Scientists already know that natural colour variation is controlled by three genes: ROSEA and ELUTA affect the intensity and pattern of the magenta pigment anthocyanin and thirdly SULFUREA affects the distribution of the yellow aurone pigment. The researchers in this study wanted to understand how plants producing magenta or yellow flowers could evolve from a common ancestor without producing in-between non-attractive flower colours such as orange.

"This is a totally different way of looking at evolution and could lead to a better understanding of the rules that govern biodiversity" explains Coen, "If we can comprehend how Antirrhinum genes interact in their natural habitat, it may help us in the future to better preserve genetic diversity".

(2) Comments posted about this in the forum
Read more...
What do a shark fin and a human leg have in common? PDF Print
User Rating: / 8
Everything Biology
Written by Catarina Amorim   
Aug 04, 2006 at 12:00 AM
One of the most important milestones in the evolution of life occurred when paired fins (and later limbs) appeared, leading to new types of locomotion. Now, in the advanced online issue of Nature1, scientists show that, although originating from different cell types, human limbs and median fins share a common developmental mechanism. These results support the idea that it was from median fins that all fins and limbs evolved, a hypothesis that has been around since the 19 century, but, until now, has never been proved.

shark_embryo

Cells expressing inositol triphosphate receptors with an engineered binding site stained with snake venom

The earliest vertebrate fossils show only well-developed dorsal and ventral (median) fins what has led researchers to suspect that these were the basis for which all paired fins and limbs evolved. However, their different location (median versus side of the body) seemed to indicate that they appeared from different cells in the embryo, which challenged the common-origin idea.

In order to investigate the issue, Renata Freitas, a Portuguese scientist, together with Guang Jun Zhang and Martin J. Cohn, all working at the department of Zoology, University of Florida, studied the embryonic development of Catshark’s fins. Catsharks are sharks found in the Atlantic and owe their name to their flat heads and long, catlike eyes.

The researchers started by marking the different cells from the embryo and following their development, in order to understand which cells originated the different parts of the shark’s body. Next, they investigated the activity of different genes during fin development. From these two experiments, Freitas and colleagues discovered that the median fin of Catsharks, although originating from different embryonic cells, uses the same genes (Hox and Tbx18) during development as limbs and paired fins.

(1) Comments posted about this in the forum
Read more...
Neural bases for language existed already 25-30 million years ago PDF Print
User Rating: / 20
Everything Archaeology
Written by Everything Science   
Jul 28, 2006 at 12:00 AM
The origin of the brain mechanisms involved in human language is a much debated subject, especially whether these mechanisms appeared independently in humans or were already present in a common ancestor of human and non-human primates. But now, research just published in the advanced online issue of Nature Neuroscience 1, found that Rhesus macaques when listening to other monkeys’ calls activate brain areas equivalent to the ones used for language in humans supporting the hypothesis that the neural basis for language existed already in a common ancestral. The discovery is a major step in understanding better language origins and evolution.

monkey
Although monkeys do not possess language, they do have an extended repertoire of sounds that have specific functions such as alerting to the presence of predators and marking various social interactions or emotional states. Interestingly, they have been shown to have regions in the brain similar to the Perisylvian area, although until now their functional significance was unknown, as was their link to the equivalent human region.
The acquisition of language is one of the most important adaptations during human evolution. Language created new human interactions and allowed ideas to bridge time and space. Among humans, babies as young as four weeks can respond to about 40 consonants, as differences in their sucking and heartbeats rates show. This ability seems to be innate, as babies from English-speaking parents react to consonants in Japanese that not exist in the English language. By the age of six, when the child enters school, the ability to react to sounds to which he/she has not been exposed in their own language is severely reduced, probably because at this point brain development rate decreases, and that is also why, after this age, it is so much more difficult to learn a second language.

Two main language centres have been identified in the human brain: Broca’s area, in the frontal lobe and Wernicke’s area, posteriorly. Both areas are found within a larger surface called the Perisylvian region, believed to be associated with language comprehension and production.
(1) Comments posted about this in the forum
Read more...
Biometrics for Secure Mobile Communications PDF Print
User Rating: / 1
Wireless and Handheld
Written by IST RESULTS   
Jul 23, 2006 at 12:00 AM
As mobile devices become increasingly ubiquitous and play ever more significant roles in our lives, ensuring the trustworthiness and security of the information being exchanged has never been more important. But clearly, strong security should not be at the expense of user acceptance. European researchers are employing biometrics and digital signing to provide a solution.

SecurePhone
http://istresults.cordis.lu/

Though security applications that verify a person’s identity based on their physical attributes, such as fingerprint readers or iris scanners, have been in use for some time, biometric security has only recently started to appear in mobile phones, PDAs and notebook computers where the need for miniaturisation represents a technological challenge.

So far biometric data has been used to tie the device to a person to prevent it from being used illegitimately if lost or stolen. But the IST project SecurePhone is taking a new approach, employing physical attributes to enable the user to digitally sign audio, text or image files, providing proof of their origin and authenticity.

“As far as we know there is no other biometrically-enabled digital signature application available for mobile devices that can guarantee security by storing and processing all sensitive information on the device’s SIM card,” explains SecurePhone technical coordinator Roberto Ricci at Informa in Italy. “Because biometric data never leaves the device’s SIM card and cannot be accessed, except by the verification module which also runs on the SIM card, the user’s biometric profile is completely safe. This is important to meet the highest privacy requirements.”

(1) Comments posted about this in the forum
Read more...
<< Start < Previous 1 2 3 4 5 6 7 8 9 10 Next > End >>

Results 41 - 48 of 175
Events Calendar
March 2010
SunMonTueWedThuFriSat
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 « Feb   Apr » 
Your Complete Science Portal
Most Read

Valid XHTML 1.0!


Mambo is Free Software released under the GNU/GPL License.