Wednesday, August 18, 2010


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Paleontologists scouring a river bank in Tanzania have unearthed a previously unknown crocodile from 105 million-year-old, mid-Cretaceous rock in the Great East African Rift System.

The discovery of the relatively lanky, cat-sized animal with mammal-like teeth and a land-based lifestyle supports a growing consensus that crocodiles were once far more diverse than they are today, dominating ecological niches in the Southern Hemisphere during the Cretaceous Period that were filled in the Northern Hemisphere by early mammals.

An international team of researchers led by Patrick O'Connor of Ohio University describes the new animal in the Aug. 5 issue of Nature. "At first glance, this croc is trying very hard to be a mammal," joked O'Connor. While numerous character traits show the animal is clearly crocodylian, he added, "A number of characteristics of this new species--including a reduction in its total number of teeth and a dentition specialized into ones similar to canines, premolars and occluding molars--are very similar to features that were critical during the course of mammalian evolution from the Mesozoic into the Cenozoic."

The researchers have dubbed the new animal Pakasuchus kapilimai. Paka is Ki-Swahili for cat, in reference to the animal's short, low skull with slicing, molar-like teeth, and souchos is from the ancient Greek for crocodile. The species name kapilimai is in honour of the late professor Saidi Kapilima of the University of Dar es Salaam, a key contributor to the NSF-supported Rukwa Rift Basin Project that led the discovery.

Despite features in Pakasuchus that are unusual for crocodylians, including an extremely flexible backbone, it clearly is a crocodile -- right down to the trademark openings in its skull and the bony plates on its back and tail.

The plates are much less pronounced around the animal's back and sides, perhaps allowing greater mobility, but it is the unusual dentition that is the most revealing difference. According to collaborator Nancy Stevens, also of Ohio University, the pivotal features distinguishing Pakasuchus from other crocodylians of the time, and since, is the complexity and differentiation in the teeth.

The high degree of fit between the upper and lower rear teeth suggest that, "This small-bodied animal occupied a dramatically different feeding niche than do modern crocodylians," said Stevens. The teeth suggest an ability to process food in a manner that current crocodylians, with their bite and swallow tactics, lack--yet it is an ability virtually all mammals possess.

The fossil skull was originally encased in hard, red sandstone, and the jaws were tightly closed, so the paleontologists looked to a medical scanning technology called X-ray computed tomography to reveal details of the teeth and skull.

"This is a good example of how a tool generally associated with medicine and materials science has allowed examination of previously inaccessible paleontological samples," said Paul Filmer, an NSF program director for sedimentary geology and paleobiology who has supported O'Connor's research. "The research was conducted to such a degree of accuracy that the complexity and mechanics of food processing could be modeled."

Despite the rock matrix, the researchers were able to create detailed digital images of the teeth accurate to 45 micrometers (millionths of a meter). Because the images were digital, they were ideal for animation, enabling the researchers to observe how the teeth fit with one another and estimate how the jaw may have moved.

The researchers looked at the entire skeleton, however, and based on a phylogenetic analysis of 236 characters, O'Connor and his colleagues placed Pakasuchus into an extinct crocodile group called the notosuchians.

With unusually mammal-like features, the notosuchians appear to have filled a range of ecological niches in the Cretaceous Period, a time when the continents of today were still separating out of the unified landmass of Pangea into somewhat smaller supercontinents including Laurasia in the north and Gondwanaland in the south.

"The research demonstrates that ecological niches have always been highly varied through Earth's history," added Filmer. "They are often filled by surprising branches like the notosuchians."

Notosuchian diversity peaked across Gondwana during the Middle and Late Cretaceous, as the supercontinent fragmented into the southern continents of today -- Afro-Arabia, Indo-Madagascar, Antarctica, Australia and South America.

"The presence of morphologically bizarre and highly specialized notosuchian crocodyliforms like Pakasuchus in the southern landmasses, along with an apparently low diversity of mammals in the same areas, has potentially profound ecological implications," added collaborator Joseph Sertich of Stony Brook University. "This entire group of crocodiles deviates radically from the 'typical' crocodile, most notably in their bizarre dentitions, demonstrating a diversification not seen in the Northern Hemisphere during this time interval."

The researchers are following their current work with a more detailed study of Pakasuchus, developing models of potential jaw movements and tooth-tooth interactions in a range of notosuchians.

"One of the most interesting aspects of a discovery like this is considering how such teeth develop in a crocodyliform," noted O'Connor. "Based on our current appreciation of tooth development in living crocodiles, notosuchians must have significantly altered developmental programs related to tooth shape, tooth number and tooth replacement patterns. This gives us a number of interesting evolutionary-developmental research questions to begin addressing using living crocodiles as models."

The research team is also currently studying a number of other fossils recently uncovered in southwestern Tanzania. Included among the Cretaceous animals are dinosaurs, different types of crocodiles and mammals. The team has also recently uncovered a new fauna from the end of the Oligocene Epoch. These discoveries provide a glimpse of animals inhabiting mainland Africa just prior to the great faunal exchange with animals from Eurasia.

(Photo: Patrick M. O'Connor, Ohio University)

The National Science Foundation


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Charles Darwin described the Venus Flytrap as 'one of the most wonderful plants in the world.' It's also one of the fastest as many an unfortunate insect taking a stroll across a leaf has discovered. But what powers this speed? Dr Andrej Pavlovič of Comenius University, Slovakia, has been studying the plants with the help of some specialised equipment and a few unlucky insects.

In the wild the Venus Flytrap grows in the bogs and savannahs of North and South Carolina. This is not a healthy environment for many plants as it is low in the nitrogen to needed to build proteins. The Venus Flytrap has overcome this problem by developing a taste for meat. It has convex bi-lobed leaves with three trigger hairs on each lobe. When something knocks these hairs twice an electrical signal flips the leaves into concave shapes. If the captured creature struggles to escape it continues to tickle the trigger hairs. This causes the plant's trap to close tighter and release enzymes to digest its prey.

Pavlovič looked at how the Flytraps snapped their leaves around their prey and thought that it might cost the plant energy to catch its food this way. To test his idea, he set up an infrared gas analyzer and a chlorophyll fluorescence imaging camera to watch the plants. He used a wire to make a trap snap and then simulated an insect struggling in the closed trap. Then he watched what happened as the plant caught its victim.

Pavlovič said: "When a trap was triggered, photosynthesis slowed down and then recovered over ten minutes after the traps stopped being stimulated. In addition, the gas analyser showed an increase in respiration from the traps. To power the trap, the Venus Flytraps converted sugars they had photosynthesized back into carbon dioxide and energy. It is like an animal which also increases breathing when it has an increased demand for energy. The measurements showed that the effects are linked not to whether or not the trap is open, but to the stimulation of the trigger hairs. The measurements are connected with electrical signals produced by trigger hair irritation. These signals are similar to the signals which spread through the animal neurons."

The results mean that the plants should not been seen as entirely passive. Pavlovič added: "These results show that the plant is as active as it appears and that it has adapted to trade-off the costs of lost photosynthesis against the benefits of additional nutrients from animal prey which in turn may later stimulate photosynthesis. This agrees with my earlier studies on carnivorous plants and shows why Venus Flytraps live in sunny habitats. The energy used in eating insects means that they need a lot of opportunity for photosynthesis, otherwise they lose more than they gain."

It also suggests an answer to a question posed by Darwin over a century ago. Pavlovič noticed that when the traps closed there were gaps between the 'teeth' at the edge of the trap that a small creature could escape through. He said: "This could be an adaptive trait. Victims with little useful nitrogen can escape, ensuring the plant doesn't waste energy digesting them. The Venus Flytrap is not a merciless killer."

Oxford University


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A consistent all-over tan may be impossible to achieve because some body areas are much more resistant to tanning than others, a study has found.

Researchers - funded by the Medical Research Council (MRC) - at the University of Edinburgh say the results explain why some holidaymakers find it so hard to achieve an even tan all over their body.

The findings, published in the journal Experimental Dermatology, show that the buttock is much more resistant to sunshine but surprisingly when it does go red it tans less well than other areas.

It was also found that people with no freckles tanned more easily than those with freckling.

The study represents the first time that the depth of a person's tan, and not just skin redness, has been quantified.

Scientists carried out the study to try and solve the puzzle of why different types of skin cancer tend to be found in different parts of the body, given that they are all caused by exposure to sunshine.

The team aimed to identify whether this is linked to variations in the way different parts of the body develop a tan.

The team analysed the skin of 100 volunteers, who were exposed to six dose of UVB on two areas of their body – their back and their buttock.

The volunteers were given an injection to minimise the rush of blood that naturally occurs after the skin is exposed to sunlight within the first 24 hours.

Researchers say this redness is often confused with the start of tanning, but in fact is the skin's signal that it has been damaged.

After seven days, the volunteers' skin was analysed to find what colour remained after the redness had died down.

This colour – recognised as a suntan – comes from the skin's production of melanin, a defence that blocks the skin absorbing too much harmful UVB radiation.

Jonathan Rees, Professor of Dermatology at the University of Edinburgh, who led the study said: "One of the real puzzles about melanoma is why the numbers of tumours differ so much depending on body site. Our work shows that in one sense we are all made up of different units of skin, which respond differently to sunshine, and which all may afford different degrees of protection against the harmful effects of sunshine."

University of Edinburgh


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First results from the LHC at CERN1 are being revealed at ICHEP, the world’s largest international conference on particle physics, which has attracted more than 1000 participants to its venue in Paris. The spokespersons of the four major experiments at the LHC – ALICE, ATLAS, CMS and LHCb – are presenting measurements from the first three months of successful LHC operation at 3.5 TeV per beam, an energy three and a half times higher than previously achieved at a particle accelerator.

With these first measurements the experiments are rediscovering the particles that lie at the heart of the Standard Model – the package that contains current understanding of the particles of matter and the forces that act between them. This is an essential step before moving on to make discoveries. Among the billions of collisions already recorded are some that contain 'candidates' for the top quark, for the first time at a European laboratory.

“Rediscovering our ‘old friends’ in the particle world shows that the LHC experiments are well prepared to enter new territory” said CERN’s Director-General Rolf Heuer. “It seems that the Standard Model is working as expected. Now it is down to nature to show us what is new.”

The quality of the results presented at ICHEP bears witness both to the excellent performance of the LHC and to the high quality of the data in the experiments. The LHC, which is still in its early days, is making steady progress towards its ultimate operating conditions. The luminosity – a measure of the collision rate - has already risen by a factor of more than a thousand since the end of March. This rapid progress with commissioning the LHC beam has been matched by the speed with which the data on billions of collisions have been processed by the Worldwide LHC Computing Grid, which allows data from the experiments to be analysed at collaborating centres around the world.

“Within days we were finding Ws, and later Zs – the two carriers of the weak force discovered here at CERN nearly 30 years ago,” said Fabiola Gianotti, spokesperson for the 3000-strong ATLAS collaboration. “Thanks to the efforts of the whole collaboration, in particular the young scientists, everything from data-taking at the detector, through calibration, data processing and distribution, to the physics analysis, has worked fast and efficiently.”

“It is amazing to see how quickly we have ‘re-discovered’ the known particles: from the lightest resonances up to the massive top quark. What we have shown here in Paris is just the first outcome of an intense campaign of accurate measurements of their properties.” said Guido Tonelli, spokesperson for CMS. “This patient and systematic work is needed to establish the known background to any new signal.”

“The LHCb experiment is tailor-made to study the family of b particles, containing beauty quarks,” said the experiment’s spokesperson Andrei Golutvin, “So it’s extremely gratifying that we are already finding hundreds of examples of these particles, clearly pin-pointed through the analysis of many particle tracks.”

“The current running with proton collisions has allowed us to connect with results from other experiments at lower energies, test and improve the extrapolations made for the LHC, and prepare the ground for the heavy-ion runs,” said Jurgen Schukraft, spokesperson for the ALICE collaboration. This experiment is optimized to study collisions of lead ions, which will occur in the LHC for the first time later this year.

Two further experiments have also already benefited from the first months of LHC operation at 3.5 TeV per beam. LHCf, which is studying the production of neutral particles in proton-proton collisions to help in understanding cosmic-ray interactions in the Earth’s atmosphere, has already collected the data it needs at a beam energy of 3.5 TeV. TOTEM, which has to move close to the beams for its in-depth studies of the proton, is beginning to make its first measurements.

CERN will run the LHC for 18-24 months with the objective of delivering enough data to the experiments to make significant advances across a wide range of physics processes. With the amount of data expected, referred to as one inverse femtobarn, the experiments should be well placed to make inroads in to new territory, with the possibility of significant discoveries.

(Photo: CERN)

European Organization for Nuclear Research


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Scientists at the Stanford University School of Medicine have identified a molecular pathway responsible for the death of key nerve cells whose loss causes Parkinson’s disease. This discovery not only may explain how a genetic mutation linked to Parkinson’s causes the cells’ death, but could also open the door to new therapeutic approaches for the malady.

In a study published July 29 in Nature, investigators used an animal model, the common fruit fly, to show that the mutation results in impaired activity of recently discovered molecules called microRNAs, which fine-tune protein production in cells. This impairment, in turn, leads to the premature death of nerve cells specifically involved in the secretion of the brain chemical dopamine. The degeneration of these so-called dopaminergic nerve cells in the brain is a hallmark of Parkinson’s.

“MicroRNA, whose role in the body has only recently begun to be figured out, has been implicated in cancer, cardiac dysfunction and faulty immune response,” said Bingwei Lu, PhD, associate professor of pathology and the study’s senior author. “But this is the first time it has been identified as a key player in a neurodegenerative disease.”

Parkinson’s is a movement disorder characterized outwardly by tremor, difficulty in initiating movement, and postural imbalance and, in the brain, by a massive loss of the dopaminergic nerve cells in areas that fine-tune motor activity. It affects an estimated 1 million people in the United States. The incidence of Parkinson’s, rare in younger people, increases dramatically with age, although nobody is sure why. Nor is it known why the most common mutation implicated in Parkinson’s — LRRK2 G2019S, found in about one-third of all Parkinson’s cases occurring among North African Arabs and North American Ashkenazi Jews — increases the likelihood of contracting the disease.

The new findings show that the LRRK2 mutation trips up the normal activity of microRNAs, resulting in the overproduction of at least two proteins that can cause certain cells, like brain cells, to die.

Understanding how microRNA can go wrong requires an understanding of its relationship to its much longer and better-known cousins, “messenger RNA” (or mRNA) molecules. The latter carry genetic recipes from a cell’s DNA to specialized molecular machines that translate the instructions into the proteins that make up a cell. In contrast, a microRNA molecule is a very short string of RNA that doesn’t contain instructions for making proteins but that can bind to parts of messenger RNA sequences that complement its own. As a result, the messenger RNA’s sequence can no longer be read by the cell’s protein-manufacturing apparatus, gumming up assembly of the protein it encodes.

It’s only recently that scientists have started to understand microRNA’s critical role.

The researchers in Lu’s lab conducted their experiments in Drosophila, the fruit fly, which has previously proved itself a useful model for several neurodegenerative disorders, yielding substantial insights into Parkinson’s, Alzheimer’s and Huntington’s diseases. They observed that certain proteins were being produced at higher-than-normal levels in the fly LRRK2 model of Parkinson’s disease. What particularly drew their attention were two proteins that are important in regulating cell division. Mature nerve cells, which no longer divide, should not have high levels of these proteins; when they do, they are prone to premature cell death.

The researchers looked at the mRNAs containing the genetic recipes for the two overproduced proteins, and predicted that they would be bound by two specific microRNAs: let-7 and miR-184. When they then manipulated the activities of those two microRNA species in flies’ brains, they had results consistent with the damage associated with Parkinson’s. Diminishing the activity of let-7 in dopaminergic nerve cells, for example, caused both the increased production of one of the suspect proteins and degeneration of the cells.

The researchers showed that toning down the levels of these two proteins, in itself, prevented dopaminergic nerve cell death in the flies. “The flies no longer got symptoms of Parkinson’s,” said Lu. “This alone has immediate therapeutic implications. Many pharmaceutical companies are already making compounds that act on these two proteins, which in previous studies have been shown to be associated with cancer. It may be possible to take these compounds off the shelf or quickly adapt them for use in non-cancer indications such as Parkinson’s.”

The researchers then went a step further, showing how the genetic mutation of LRRK2 caused interference with microRNA molecules' ability to inhibit their target mRNAs. It leads to the disruption of a huge complex of molecular machinery that must operate smoothly in order for microRNA to do its job. This link between the common Parkinson’s-producing mutation and consequent microRNA malfunction is a new finding.

“The clinical impact of our findings may be five to 10 years down the road,” Lu said. “But their impact on our understanding of the disease process is immediate. We can now start testing compounds in mammals and cultured human dopaminergic cells to see if they can inhibit overproduction of these proteins and stave off dopaminergic cell death.” Currently available drugs for Parkinson’s disease temporarily alleviate its symptoms but can have undesirable side effects, and they don’t prevent dopaminergic cells from dying.

(Photo: Stanford U.)

Stanford University


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Combining nature and Greek mythology, researchers at the Technion-Israel Institute of Technology have developed a tiny "Trojan Horse" system for delivering cancer-fighting drugs. With this system, the drugs are delivered only once they are inside the cancerous cells, so there is no damage to the healthy cells in the surrounding area.

The researchers created the system by attaching folic acid and an anticancer drug to an extract from the coniferous Larix (Larch) tree, which is among the dominant plants in the immense boreal forests of Russia and Canada.

“We were looking for a natural polymer that would be highly soluble in water, and found it in a polysaccharide known as arabinogalactan, which is extracted from the Larix,” explains lead researcher Dr. Yoav Livney, of the Technion Faculty of Biotechnology and Food Engineering and the Technion Russell Berrie Nanotechnology Institute.

Certain cancerous cells produce between 10 to 100 times more folate receptors than healthy cells. These receptors bind folic acid, which is required by cancer cells to grow and divide rapidly. As a result, the researchers used folic acid as the bait for targeting cancer cells.

Once the folic acid is bound to the receptor, a process is triggered whereby the cell membrane folds inward, creating a “bubble” (organelle) called an endosome. These endosomes fuse with other naturally-occurring organelles termed lysosomes, which contain enzymes that serve as the digestive system of the cell.

Dr. Livney and Prof. Yehuda Assaraf (of the Technion Faculty of Biology and head of the Fred Wiszkowski Cancer Research Lab) designed the novel drug delivery system by attaching an antitumor drug to the polysaccharide by a small fragment of a protein (a peptide), which is digested by the enzymes present in the lysosome. As a result, the anticancer drug is released only in the lysosome, because there are no equivalent enzymes in the blood that can break down this specific peptide.

The development is expected to be especially efficient against ovarian, kidney and uterine cancer, which are characterized by high production of folic acid receptors. In the future, this novel chemotherapeutic delivery system will be able to simultaneously deliver several anti-cancer drugs, whose tailor-made synergistic combination would lead to an optimal eradication of malignant cells of a specific cancer type, in individual cancer patients.

(Photo: ATS)

American Technion Society


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An archaeologist studying a remote Pacific island, world famous for its strange stone statues, says outsiders - and not its ancestors - should be blamed for its historic demise hundreds of years ago.

Dr Karina Croucher from The University of Manchester says her research backs a growing body of opinion which casts new light on the people living on the island of Rapa Nui, named ‘Easter Island’ by its discoverers in 1722.

“Easter Islanders’ ancestors have been unfairly accused by Westerners of being primitive and warlike, for toppling statues - or moai - and for over-exploiting the island’s natural resources,” she said.

But the art which adorns Easter Island’s landscape, volcanoes and statues, body tattoos and carved wooden figurines, when examined together, show a different picture of what the islanders were like, according to Dr Croucher.

“The carved designs - including birds, sea creatures, canoes and human figures - mimic natural features already visible in the landscape and show their complex relationship to the natural environment,” she said.

“They were a people who saw themselves as connected to the landscape, which they carved and marked as they did their own bodies and the moai statues.

“These people must have had a sophisticated and successful culture – until the Westerners arrived - and it is time we recognise that.

“Early expedition accounts repeatedly show the islanders produced a trading surplus – they were successful and self sufficient.

“It must have been quite a place to live: I imagine the sounds of the carvers dominating the soundscape as they worked on the rock.”

Dr Croucher, whose research is funded by the British Academy, added: “There is a growing body of opinion which says history has been unkind to the Easter Islanders - and my research confirms and underlines that.

“Rather than a story of self-inflicted deprivation, I agree with the view that substantial blame has to rest with Western contact, ever since Easter Island’s first sighting by Jacob Roggeveen in 1722.

“Visitors brought disease, pests and slavery, resulting in the tragic demise of the local population and culture.

“There is little archaeological evidence to support the history of internal warfare and collapse before contact with the outside world.”

Easter Island’s 19th Century history is a sad one: slave raids in 1862 reduced the Island’s population A few islanders survived slavery and were returned home, bringing with them small pox and other diseases.

The missionaries converted the remaining population to Christianity, encouraging them to abandon their traditional beliefs.

Even then, several hundred inhabitants were driven off the island to work on sugar plantations in Tahiti. By 1877, a population of just 110 people was recorded.

The academic, based at The School of Arts, Histories and Cultures, said: “Explorer Thor Heyerdahl famously asserted that it was South Americans who built the moai.

“However, rather than relying on the arrival of a South American fleet of carvers and sculptors, it is clear the moai, rock art and tattooing are very much part of the same tradition, which has Polynesian roots.

“The statues and rock art, although difficult to date with certainty, are the result of a population which flourished on the island until outside contact set the tragic course for the Island’s demise.”

(Photo: U. Manchester)

University of Manchester


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While women have been making a fashion statement in high heels for years -- wearing trendy stilettos, wedges, pumps and kitten heels -- there's reason for concern about what those heels may be doing to their knees and joints over time. A new study by an Iowa State University kinesiology master's student has found that prolonged wearing of and walking in high heels can contribute to joint degeneration and knee osteoarthritis.

Danielle Barkema, the ISU student who is originally from Cedar Falls, recently completed her thesis research studying the effects of high-heeled walking on forces acting on lower extremity joints. Kinesiology professor and department chair Phil Martin assisted her in the study, which will be presented, in part, at the annual meeting of the American Society of Biomechanics (ASB), Aug. 18-21, at Brown University in Providence, R.I.

"Obviously with research like this, you can't say with any certainty that if you wear high heels regularly you will develop osteoarthritis. We don't know that," Barkema said. "There are probably people [high heel wearers] who do and those who do not. However, based on this information, wearing high heels puts individuals at greater risk for developing osteoarthritis. And it seems to be that the higher the heel height, the greater the risk."

Barkema selected three different heel heights -- flat, two inches, and 3.5 inches-- and had each of the 15 women in her study complete walking trials. She measured the forces acting about the knee joint and the heelstrike-induced shock wave that travels up the body when walking in heels. Using sensors, accelerometers and lab equipment such as a force platform and markers/cameras, she was able to capture motion and force data and translate them into results that could change the way millions of women select their footwear.

While previous studies have examined the effect of high heels on joints, the ISU researchers found that heel height changes walking characteristics such as slower speeds and shorter stride lengths. And as the heels got higher, they also saw an increase in the compression on the inside -- or medial side-- of the knee.

"This means that prolonged wearing and walking in heels could, over time, contribute to joint degeneration and knee osteoarthritis," Barkema said.

"I think Danielle's exactly right. Wearing high heels regularly puts a person at risk and the higher the heel, the greater the risk," Martin added. "The loading that's being produced in the joint with every step that they take is higher -- or at least, these data suggest that. These are not direct measures of loading within the joint, but they're an alternative way of looking at that kind of loading."

Barkema also found that in addition to lower extremity joint problems, wearing heels - especially those two inches and higher - alters body posture by changing joint positions at the ankle, knee, hip, and trunk, which can create strain on the lower back.

"Visually, it's quite apparent that somebody's posture is altered when wearing high heels," she said. "We noted those changes in posture [in the study], as well as various joint angles, such as the knee and ankle angle. The most dramatic change occurs at the ankle."

The idea for the research thesis topic actually came from Barkema's twin sister, Ashley, who saw the physical toll regular high heel wear was having on her co-workers.

"Ashley began work as a retail manager at a well-known department store in Chicago a few years ago," Barkema said. "She, as well as most of her co-workers, wore high heels on a daily basis. She noticed a lot of the women, especially older women who had been wearing high heels regularly, had various problems -- problems with their knees and hips, etc."

Barkema's sister served as one of the subjects in the study. And Danielle's not advising her sister to stop wearing high heels altogether.

"I tell my friends to try to wear high heels in moderation and, if possible, to wear lower heels," she said.

The research being presented at the ASB meeting will feature one of the two parts of the study -- focusing on results on tibia acceleration, or impact, in relation to heel height. Those results curiously found the peak impact to be in the two inch heels, with the higher heels actually diminishing the impact similar to the flats.

The researchers plan to submit future papers on all their findings to professional journals.

(Photo: Bob Elbert, ISU News Service)

Iowa State University


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What would happen if you developed a strong opinion on an issue, and later found that the majority of people disagreed with you?

You might think that such a revelation would encourage you to rethink your beliefs. But a new study suggests people often react just the opposite: people grow more confident in some beliefs when they find out later that a majority of people disagree with them.

“It may be that you feel proud because you were able to disprove, in your own mind, an opinion that most people have accepted,” said Richard Petty, co-author of the study and professor of psychology at Ohio State University.

“You actually become doubly sure you were right.”

Petty conducted the study with Pablo Briñol, a former postdoctoral fellow at Ohio State, and Javier Horcago, both at the Universidad Autónoma de Madrid in Spain. Their results appear online in the Journal of Personality and Social Psychology and will be published in a future print edition.

The research continues a long tradition in psychology of examining how people are influenced by majority or minority opinion on a subject, Petty said.

Previous research has shown that majority opinion has the greatest influence on people when they consider issues that aren’t that important to them or issues they don’t want to spend much effort thinking about.

“If a decision isn’t important, it often seems easiest to just go along with what everybody else is thinking,” Petty said.

Minority opinion does have influence sometimes, but mostly on issues which people are motivated to consider carefully.

However, previous work had focused on situations in which people found out the majority opinion before they had given the issue much thought. Petty and his co-authors approached it from a different angle: what happens when people find out the majority opinion on an issue after they’ve already thought about the issue themselves?

Results showed that when students had a negative view of the company because of the weak arguments presented, they were actually more confident in this belief when they learned the majority of their fellow students disagreed with them and had positive views of the company (as opposed to when the majority agreed with their negative views).

The researchers did a series of related experiments involving undergraduate students in Spain. In one key experiment, students were told they would be examining the organizational conditions of an unfamiliar international company where they might be able to work for a future internship.

Participants were given either strong or weak arguments in favor of the firm. (One strong argument was that workers reported high satisfaction because of the flexibility of their work schedules. One weak argument was that the logo of the company was very attractive.)

After hearing either the strong or the weak arguments, the students were asked to list their thoughts about the company. As expected, students presented the weak arguments generated negative thoughts about the company, while those presented strong arguments generated positive thoughts.

At that point, half the students were told that 86 percent of their fellow students supported the company, while the other half were told only 14 percent supported the company.

After learning whether the majority of their fellow students agreed or disagreed with their analysis of the company, the students were asked to rate how confident they were in the positive or negative thoughts they had listed, and then rated their attitude toward the company.

Results showed that when students had a negative view of the company because of the weak arguments presented, they were actually more confident in this belief when they learned the majority of their fellow students disagreed with them and had positive views of the company (as opposed to when the majority agreed with their negative views).

“People may be thinking that ‘if I can find the flaws in a position that the majority of people believe, then my thoughts must really be good ones,’” Petty said.

One key to this finding is that people have to think about the issue first, and develop their own ideas, Petty said. Learning later that a majority of people hold a certain view, after you have already made up your mind, functions to help you validate what you already think about that issue, Petty said.

The results suggest how would-be persuaders could strategically reveal the majority or minority status of a proposal to achieve the maximum persuasive effect.

If you feel you have a weak argument, it should be best to suggest right away that a lot of people support your issue, before you make your case. In that case, you’re hoping that the majority endorsement will prevent people from counterarguing. People will rely on the “wisdom of the crowd” to guide their thoughts, without actually considering the issue, Petty explained.

If you tell people you have majority support after you make your weak arguments, it is too late – it will only serve to give people confidence in the negative thoughts they have generated about your cause, Petty said.

But for those with a strong argument, it can be helpful to reveal wide support for your proposal after explaining it, as this gives people confidence in the positive thoughts they have generated to your strong arguments, Petty said.

The study was supported by a grant from the National Science Foundation.

(Photo: OSU)

Ohio State University


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Just because salsa is acidic, don’t assume it can’t make you ill. A University of Florida researcher’s study shows that salmonella and staphylococcus can both survive long enough to pose risk in the often free, always popular appetizer.

In a research paper published in the June issue of the Journal of Food Protection, Amy Simonne, an associate professor of food safety and quality, found that when samples of restaurant-prepared red salsa were contaminated with salmonella and Staphylococcus aureus, the illness-causing micro-organisms survived long enough to pose a food safety risk.

Red salsa is a staple in Mexican restaurants, often served as a free appetizer with tortilla chips. Because it is almost automatically served in many establishments, it is in and out of refrigerators — and sometimes kept at room temperature for long stretches, she said.

In her study, Simonne’s team, which included former UF graduate student Wendy Franco and Wei-Yea Hsu, bought several batches of red salsa from one Mexican-style chain restaurant. They checked its temperature, then whisked the samples to a lab, where they added salmonella or S. aureus. The samples, some refrigerated, some not, were then monitored for several days to determine how long the micro-organisms were present.

Salmonella infection is among the most common foodborne illnesses, often the result of eating raw or undercooked meat, poultry or eggs. Its symptoms can include abdominal pain, fever, nausea and vomiting. In a kitchen setting, S. aureus, known as staph, is often transferred to food by someone whose hands aren’t clean. It can cause skin infections and digestive problems.

Simonne, who has been studying ethnic foods since 2004 with UF’s Institute of Food and Agricultural Sciences, found that salmonella survived in all samples stored at room temperature, although S. aureus significantly decreased after 24 hours at room temperature.

But the study showed that both can survive in salsa long enough to represent a food safety risk at both refrigerated and room temperatures. Although S. aureus had a shorter life span in the salsa, the bacteria survived long enough to make the samples unfit for human consumption, she said.

Many diners assume that because salsa has a pH of less than 4, meaning it is acidic, illness-causing bacteria won’t survive in it, she said. But food scientists have shown that acidic foods can also cause problems, she noted, citing outbreaks of E. coli in unpasteurized apple cider and salmonella in fresh orange juice.

For snackers, the best news is that Simonne isn’t saying consumers should steer clear of salsa, only that food handlers should be vigilant about not keeping refrigerated salsa more than seven days and minimize the time it’s unrefrigerated.

And they should take care, as always, to follow hand-washing guidelines and ensure that ingredients are properly washed before preparation.

(Photo: Tyler Jones, UF/IFAS)

University of Florida


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What could be as alluring as a lady in red? A gentleman in red, finds a multicultural study published Aug. 2 in the Journal of Experimental Psychology: General.

Simply wearing the color red or being bordered by the rosy hue makes a man more attractive and sexually desirable to women, according to a series of studies by researchers at the University of Rochester and other institutions. And women are unaware of this arousing effect.

The cherry color's charm ultimately lies in its ability to make men appear more powerful, says lead author Andrew Elliot, professor of psychology at the University of Rochester. "We found that women view men in red as higher in status, more likely to make money and more likely to climb the social ladder. And it's this high-status judgment that leads to the attraction," Elliot says.

Why does red signal rank? The authors see both culture and biology at work. In human societies across the globe, red traditionally has been part of the regalia of the rich and powerful. Ancient China, Japan and sub-Saharan Africa all used the vibrant tint to convey prosperity and elevated status, and Ancient Rome's most powerful citizens were literally called "the ones who wear red." Even today, the authors note, businessmen wear a red tie to indicate confidence, and celebrities and dignitaries are feted by "rolling out the red carpet."

Along with this learned association between red and status, the authors point to the biological roots of human behavior. In non-human primates, like mandrills and gelada baboons, red is an indicator of male dominance and is expressed most intensely in alpha males. Females of these species mate more often with alpha males, who in turn provide protection and resources.

"When women see red it triggers something deep and probably biologically engrained," explains Elliot. "We say in our culture that men act like animals in the sexual realm. It looks like women may be acting like animals as well in the same sort of way."

To quantify the red effect, the paper analyzed responses from 288 female and 25 male undergraduates to photographs of men in seven different experiments. Participants were all self-identified as heterosexual or bisexual. In one color presentation, participants looked at a man's photo framed by a border of either red or white and answered a series of questions, such as: "How attractive do you think this person is?"

Other experiments contrasted red with gray, green, or blue. Colors were precisely equated in lightness and intensity so that test results could not be attributed to differences other than hue.

In several experiments, the shirt of the man in the photographs was digitally colored either red or another color. Participants rated the pictured man's status and attractiveness, and reported on their willingness to date, kiss, and engage in other sexual activity with the person. They also rated the man's general likability, kindess, and extraversion.

The researchers found that the red effect was limited to status and romance: red made the man seem more powerful, attractive, and sexually desirable, but did not make the man seem more likable, kind, or sociable. The effect was consistent across cultures: undergraduates in the United States, England, Germany, and China all found men more attractive when wearing or bordered by red.

And the effect was limited to women. When males were asked to rate the attractiveness of a pictured male, color made no difference in their responses.

Across all the studies, the influence of color was totally under the radar. "We typically think of color in terms of beauty and aesthetics," say Elliot. "But color carries meaning as well and affects our perception and behavior in important ways without our awareness."

In earlier work, Elliot documented that men are more attracted to women in red. But the red effect depends on the context. Elliot and others have also shown that seeing red in competitive situations, such as IQ tests or sporting events, leads to worse performance.

(Photo: University of Rochester)

University of Rochester


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Wielding two claws, a motor and a tail that swings like a grandfather clock's pendulum, a small robot named ROCR ("rocker") scrambles up a carpeted, 8-foot wall in just over 15 seconds – the first such robot designed to climb efficiently and move like human rock climbers or apes swinging through trees.

"While this robot eventually can be used for inspection, maintenance and surveillance, probably the greatest short-term potential is as a teaching tool or as a really cool toy," says robot developer William Provancher, an assistant professor of mechanical engineering at the University of Utah.

His study on development of the ROCR Oscillating Climbing Robot is set for online publication this month by Transactions on Mechatronics, a journal of the Institute of Electrical and Electronics Engineers and American Society of Mechanical Engineers.

Provancher and his colleagues wrote that most climbing robots "are intended for maintenance or inspection in environments such as the exteriors of buildings, bridges or dams, storage tanks, nuclear facilities or reconnaissance within buildings."

But until now, most climbing robots were designed not with efficiency in mind, only with a more basic goal: not falling off the wall they are climbing.

"While prior climbing robots have focused on issues such as speed, adhering to the wall, and deciding how and where to move, ROCR is the first to focus on climbing efficiently," Provancher says.

One previous climbing robot has ascended about four times faster than ROCR, which can climb at 6.2 inches per second, but ROCR achieved 20 percent efficiency in climbing tests, "which is relatively impressive given that a car's engine is approximately 25 percent efficient," Provancher says.

The robot's efficiency is defined as the ratio of work performed in the act of climbing to the electrical energy consumed by the robot, he says.

Provancher's development, testing and study of the self-contained robot was co-authored by Mark Fehlberg, a University of Utah doctoral student in mechanical engineering, and Samuel Jensen-Segal, a former Utah master's degree student now working as an engineer for a New Hampshire company.

The National Science Foundation and University of Utah funded the research.

Other researchers have studied a variety of ways for climbing robots to stick to walls, including dry adhesives, microspines, so-called "dactyl" spines or large claws like ROCR's, suction cups, magnets, and even a mix of dry adhesive and claws to mimic wall-climbing geckos.

Now that various methods have been tried and proven for robots to climb a variety of wall surfaces, "if you are going to have a robot with versatility and mission-life, efficiency rises to the top of the list of things to focus on," Provancher says.

Nevertheless, "there's a lot more work to be done" before climbing robots are in common use, he adds.

Some previous climbing robots have been large, with two to eight legs. ROCR, in contrast, is small and lightweight: only 12.2 inches wide, 18 inches long from top to bottom and weighing only 1.2 pounds.

The motor that drives the robot's tail and a curved, girder-like stabilizer bar attach to the robot's upper body. The upper body also has two small, steel, hook-like claws to sink into a carpeted wall as the robot climbs. Without the stabilizer, ROCR's claws tended to move away from the wall as it climbed and it fell.

The motor drives a gear at the top of the tail, causing the tail to swing back and forth, which propels the robot upward. A battery is at the end of the tail and provides the mass that is necessary to swing the robot upward.

"ROCR alternatively grips the wall with one hand at a time and swings its tail, causing a center of gravity shift that raises its free hand, which then grips the climbing surface," the study says. "The hands swap gripping duties and ROCR swings its tail in the opposite direction."

ROCR is self-contained and autonomous, with a microcomputer, sensors and power electronics to execute desired tail motions to make it climb.

Provancher says that to achieve efficiency, ROCR mimics animals and machines.

"It pursues this goal of efficiency with a design that mimics efficient systems both in nature and manmade," he says. "It mimics a gibbon swinging through the trees and a grandfather clock's pendulum, both of which are extremely efficient."

The study says: "The core innovations of ROCR – its energy-efficient climbing strategy and simple mechanical design – arise from observing mass shifting in human climbers and brachiative [swinging] motion in animals."

Before testing the robot itself, Provancher and colleagues used computer software to simulate ROCR's climbing, using such simulation to evaluate the most efficient climbing strategies and fine-tune the robot's physical features.

Then they conducted experiments, varying how fast and how far the robot's tail swung, to determine how to get the robot to climb most efficiently up an 8-foot-tall piece of plywood covered with a short-nap carpet.

The robot operated fastest and most efficiently when it ran near resonance – near the robot's natural frequency – similar to the way a grandfather clock's pendulum swings at its natural frequency. With its tail swinging more slowly, it climbed but not as quickly or efficiently.

The researchers found it achieve the greatest efficiency – 20 percent – when the tail swung back and forth 120 degrees (or 60 degrees to each side of straight down), when the tail swung back and forth 1.125 times per seconds and when the claws were spaced 4.9 inches apart.

When the tail swung at two times per second, it was too fast and ROCR jumped off the wall, and was caught by a safety cord so it wasn't damaged.

Provancher says the study is the first to set a benchmark for the efficiency of climbing robots against which future models may be compared. He says future work will include improving the robot's design, integrating more complex mechanisms for gripping to walls of various sorts, such as brick and sandstone, and investigating more complex ways of controlling the robot – all aimed at improving efficiency.

"Higher climbing efficiencies will extend the battery life of a self-contained, autonomous robot and expand the variety of tasks the robot can perform," he says.

(Photo: William Provancher, The University of Utah)

University of Utah




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