Anthropology News, Science News - Scicornwall.com

The stable Kaye effect and leaping shampoo

During my Youtube travels I also found a great demonstration on the Kaye effect, cool fluid physics anyone!

An anthropological introduction to YouTube

Found this interesting video on youtube of Michael Wesch of the anthropology of Youtube!

Changes to the sites RSS feed

For all of the people who have subscibed to the Science Cornwall RSS feed I would like to warn you that the feed from feedburner will be discontinued soon.

Please revisit the blog and subscirbe to the new feed. It should be http://www.scicornwall.com/index.rdf but I am unsure if this will work straight away.

Thankyou and I hope to see you back soon !

Sam

Dartmouth researchers say too many children see extreme violence in movies

Study questions the effectiveness of the current movie-rating system

In a paper published in the August issue of the journal Pediatrics, Dartmouth researchers document the alarming numbers of young adolescents age 10-14 who are exposed to graphic violence in movies rated R for violence. They found that these extremely violent movies were seen by an average of 12.5 percent of an estimated 22 million children age 10-14. One R-rated movie, Scary Movie, was seen by an estimated 10 million children, or about 48 percent of 10-14 year olds.

"Our data reveal a disturbingly high rate of exposure among 10-14 year olds nationally to extremely violent movies," says Keilah Worth, the lead author on the study and a post-doctoral fellow at Dartmouth Medical School and at Dartmouth-Hitchcock Medical Center's Norris Cotton Cancer Center. "In Britain, no adolescent would be admitted to these movies unless they were 18. The R rating in this country is clearly not preventing our young people from seeing them."

Many scientific studies have established the connection between exposure to media violence and aggression and violence in children. For example, playing video games can lead to changes in attitudes and behavior as well as desensitization to actual violence.

"We know so much about the harmful effects of exposure to violent media content, but how much exposure children actually get has been largely ignored. Now, we're learning more about the large numbers of kids seeing this material and who they are," says Worth.

For this assessment of exposure to violence in movies, the researchers used data from national telephone surveys of more than 6,500 adolescents age 10-14 in 2003. Out of 532 recent releases, the researchers chose to look at exposure to 40 of the most violent movies. The study also revealed some independent risk factors for exposure: boys, minorities, those with lower socioeconomic status, and those with lower academic performance were all more likely to see extremely violent movies. Black male adolescents were at particularly high risk of seeing these movies. For example, Blade, Training Day, and Scary Movie were seen by 37 percent, 27 percent, and 48 percent respectively of all the adolescents surveyed, compared to 82 percent, 81 percent, and 81 percent of black males.

"No expert in child development would advocate for subjecting children as young as 10 to this level of violence, yet the study shows that such exposure is commonplace in this country," says James Sargent, the senior scientist on this study and a professor of pediatrics at Dartmouth Medical School. "We should re-think the current movie rating system, which has been in place for 40 years, and was designed when kids could only see movies in theaters. Ratings need to be more prominent on all movies, whether they are seen in theaters or purchased in the store, and we need clearer messages to parents. Pediatricians and child advocates should instruct parents to strictly abide by the movie-age guidelines and to closely monitor movie viewing."

Venemous species of cuttlefish has given up swimming for walking.

Here is a little video of the Cuttlefish and its flamboyent colours

This species is well worth highlighting for its beauty and rarity. They are highly prized on a divers must see list. Distribution, central indo region, southern Philippines to Northern Australia.

Once discovered, instead of leaving the area they will usually stay in the same place for some months so revisiting is possible. Rather than seeing this species swimming they prefer to walk the substrate on two front tentacles and two skin flaps located on the underbelly, this is clearly illustrated within our field guide images. Look for the sandy appearance on the "walking" front tentacles and the underbelly skin flaps, this is where the creature makes contact with the substrate.

They are active in daylight hours and their coloration is generally brown to match the substrate (darker in Indonesia due to darker sand).

They show flamboyant displays of red, yellow, white and pink chevrons that move up and down their bodies pulsating in a mesmerizing rhythm. Like other cuttlefish they produce instant colour changes.

Their elaborate coloration may indicate a poisonous bite like its cousin the Blue Ringed Octopus.

Their maximum size is approx. 10cm. Imperial Partner Shrimps live a symbiotic relationship with many creatures including cuttlefish for more information please visit our Marine Biology Crustacean page.

Researchers find cancer-inhibiting compound under the sea

University of Florida College of Pharmacy researchers have discovered a marine compound off the coast of Key Largo that inhibits cancer cell growth in laboratory tests, a finding they hope will fuel the development of new drugs to better battle the disease.

The UF-patented compound, largazole, is derived from cyanobacteria that grow on coral reefs. Researchers, who described results from early studies today (Aug. 7) at an international natural products scientific meeting in Athens, Greece, say it is one of the most promising they've found since the college's marine natural products laboratory was established three years ago.

An initial set of papers in the Journal of the American Chemical Society also has garnered the attention of other scientists, and the lab is racing to complete additional research. The molecule's natural chemical structure and ability to inhibit cancer cell growth were first described in the journal in February and the laboratory synthesis and description of the molecular basis for its anticancer activity appeared July 2.

"It's exciting because we've found a compound in nature that may one day surpass a currently marketed drug or could become the structural template for rationally designed drugs with improved selectivity," said Hendrik Luesch, Ph.D., an assistant professor in UF's department of medicinal chemistry and the study's principal investigator.

Largazole, discovered and named by Luesch for its Florida location and structural features, seeks out a family of enzymes called histone deacetylase, or HDAC. Overactivity of certain HDACs has been associated with several cancers such as prostate and colon tumors, and inhibiting HDACs can activate tumor-suppressor genes that have been silenced in these cancers.

Although scientists have been probing the depths of the ocean for marine products since the early 1960s, many pharmaceutical companies lost interest before researchers could deliver useful compounds because natural products were considered too costly and time-consuming to research and develop.

Many common medications, from pain relievers to cholesterol-reducing statins, stem from natural products that grow on the earth, but there is literally an ocean of compounds yet to be discovered in our seas. Only 14 marine natural products developed are in clinical trials today, Luesch said, and one drug recently approved in Europe is the first-ever marine-derived anticancer agent.

"Marine study is in its infancy," said William Fenical, Ph.D., a distinguished professor of oceanography and pharmaceutical sciences at the University of California, San Diego. "The ocean is a genetically distinct environment and the single, most diverse source of new molecules to be discovered."

The history of pharmacy traces its roots back thousands of years to plants growing on Earth's continents, used by ancient civilizations for medicinal purposes, Fenical added. Yet only in the past 30 years have scientists begun to explore the organisms in Earth's oceans, he said. Fewer than 30 labs exist worldwide and research dollars have only become available in the past 15 years.

HDACs are already targeted by a drug approved for cutaneous T-cell lymphoma manufactured by the global pharmaceutical company Merck & Co. Inc. However, UF's compound does not inhibit all HDACs equally, meaning a largazole-based drug might result in improved therapies and fewer side effects, Luesch said.

Since 2006, Luesch and his team of researchers have screened cyanobacteria provided by collaborator Valerie Paul, Ph.D., head scientist at the Smithsonian Marine Station in Fort Pierce. They check the samples for toxic activity against cancer cells and last year encountered one exceptionally potent extract — the one that ultimately yielded largazole.

To conduct further biological testing on the compound, Luesch and his team have been collaborating with Jiyong Hong, an assistant professor in the department of chemistry at Duke University, to replicate its natural structure and its actions in the laboratory.

Luesch said that within the next few months he plans to study whether largazole reduces or prevents tumor growth in mice.

Luesch has several other antitumor natural products from Atlantic and Pacific cyanobacteria in the pipeline.

"We have only scratched the surface of the chemical diversity in the ocean," Luesch said. "The opportunities for marine drug discovery are spectacular."

University of Florida

Vegetarian spider - Small jumping species steals lunch from ants.

A little eight-legged pickpocket that darts around acacia trees could be the first known vegetarian spider.

Bagheera kiplingi belongs among the big-eyed, athletic predators in the family of jumping spiders and gets its name from a panther in a Rudyard Kipling story. Yet a population of these spiders in Mexico mostly eats bits of the acacia trees, says Christopher Meehan of Villanova University in Pennsylvania.

A few other spider species do taste vegetable matter now and then, says Yael Lubin of Ben-Gurion University in Sede Boqer, Israel. Male crab spiders that spend their brief mating-oriented adult lives sitting on flowers will sip nectar for a little energy boost. And some baby spiders eat spores that have stuck to a web. But on hearing about spiders specializing in stealing vegetarian food, “I was absolutely floored,” Lubin says.

These arachnid herbivores are no wimps. “The tree is full of biting, vicious ant guards,” Meehan said during the 12th International Behavioral Ecology Congress meeting August 9 through 15 at Cornell University. The little spider spends its life dodging patrols of ants and stealing their (vegetarian) lunches.

Acacia trees and their resident ants have become a textbook example of a mutually beneficial partnership. Tree thorns grow swollen bases the right size to shelter ants. Glands at the base of the leaves ooze nectar, far from flowers but just at the spot to offer refreshment for ants. Acacia leaflet tips sprout nubbins of protein and fat suitable for ant snacks.

Certain ant species take full advantage of these comforts and defend their home trees against all comers. In the course of their vigilance, the ants get rid of caterpillars and other invaders that might chew on the tree.

Meehan says the spiders manage to dodge the ants, perching on leaf tips and nesting in mature leaves, which aren’t as heavily patrolled as other tree parts.

Ecologists have studied the partnership for years, but “people who look at ant acacias — they look at the ants,” Lubin says. “It took the eyes of a student naturalist to see this.”

That fresh observer was Meehan, who, along with his Villanova colleague Robert Curry, noticed the spiders dining on the leafy snacks of acacias in Mexico. In videos of 140 spider meals, the researchers counted 136 acacia protein-fat snacks with a few nectar sips. On four occasions the spiders did turn to meat as they tugged away ant larvae from a passing nursemaid and ate the youngsters.

In Costa Rica, the spiders also steal ant food, though to a lesser extent, according to observations from Eric Olson of Brandeis University. He independently discovered the spiders eating tree snacks in Costa Rica in 2001 and is working with the Villanova team on a report on the species.

Those meat moments don’t happen often, according to studies done in collaboration with Matt Reudink and others of Queen’s University in Kingston, Canada. The team checked spider tissue for the heavier form of nitrogen, N15, which becomes more concentrated as animals eat animals that have eaten other animals.

That carnivore signal does not show up in the acacia-tree spiders, which carry a relatively light concentration of N15, one that is typical of plant-eaters, according to the team’s data. He also found that the concentration of the heavier form of carbon, C13, also looks typical for a vegetarian.

Sourced from Science News

Tiny invasive snail impacts Great Lakes, alters ecology

Long a problem in the western U.S., the New Zealand mud snail currently inhabits four of the five Great Lakes and is spreading into rivers and tributaries, according to a Penn State team of researchers. These tiny creatures out-compete native snails and insects, but are not good fish food replacements for the native species.

"These snails have an operculum, a door that closes the shell," says Edward P. Levri, associate professor of biology at Penn State's Altoona Campus. "They can be out of the water for longer than other snails and when fed to fish, they are not digested and sometimes come out alive. This has a potential to alter the salmon and trout fisheries because they alter the food chain."

The New Zealand mud snail grows to a maximum of a quarter of an inch and is more normally a sixteenth to an eighth of an inch in length. The hard shell is capable of sealing off the soft animal from outside influences. In New Zealand, the snails reproduce asexually, resulting in identical clones, or sexually. However, in invaded areas, asexual cloning is the only mode of reproduction.

This mud snail spread to England as early as 1850 and Europe in the late 1800s. It is found in Japan, but when the snail arrived there is unknown. The first mud snail found in the U.S. was in 1987 in the Snake River, Idaho, but the species did not appear in the east until 1991 in Lake Ontario. The western and eastern U.S. populations are separate episodes of introduction, because they represent different clones; in each case, only one snail needed to be introduced to begin the invasion. The snails in the Great Lakes region appear to be the same as one clone found in Europe.

"In the western U.S., this species is of special concern largely because of their ability to modify ecosystems," Levri told attendees today (Aug. 8) at the Ecological Society of America's annual meeting in Milwaukee.

The snails in western streams alter the nitrogen and carbon cycling. They are primarily grazers and detritus eaters with very wide food preferences. In some places in streams in Yellowstone National Park, they reach population densities of 323 individuals per square inch. Levri, working with undergraduates Warren J. Jacoby, Shane J. Lunen, Ashley A. Kelly and Thomas A. Ladson, found that densities in the Great Lakes are not anywhere near that in the West.

"In our most recent survey, we were lucky if we found a few hundred per square meter," says Levri. "In Lake Erie they are not very abundant, but it is unclear what they are doing 100 feet below the surface."

In New Zealand, the mud snails are not a problem because of native trematodes -- flukes -- that infect the snails and controls their population and reproduction. Some people have suggested that those who want to control the snail introduce this trematode to the U.S. to control the snails.

"There are two problems with introducing these trematodes," says Levri. "The first is that any introduction of a nonnative species can cause worse problems than they were expected to cure. The second is that these flukes have a multiple-host life cycle, infecting ducks that are apparently not affected before infecting the snails. This might work in the west where the snails are in shallow water, but no duck is going to dive 100 feet to get snails."

Levri and his team found that in Lake Ontario, the densities of the snails peak between 50 and 82 feet and they were rarely found in water less than 16 feet.

"What we can do is limit their expansion," says Levri. "That means that recreational water users must be very careful moving from one place to another. We advise anglers to freeze waders and fishing gear, or use Formula 409 or something like that to kill the snails."

He notes that signs are beginning to mark areas in New York where the snail is found to warn people to clean their gear.

The Penn State researcher warns that the snails are difficult to control, noting "I have frozen them for 12 hours at a time and about 50 percent of them survive."

With thanks to the Penn StateUniversity