Archive for the ‘Plos One’ Category

CNSPhoto-WHALES
New high resolution satellite image processing technology allows researchers to identify and count right whales at the ocean surface or to depths of up to 15 metres — described as a boon to tracking the health of whale populations.

The very trait that pushed southern right whales close to extinction — lolling near the surface of warm waters — is helping to revolutionize the way whales are counted.

New satellite technology has allowed the use of high-resolution photographs and image processing software to detect the crustaceans at the surface or to a depth of 15 metres in shallow waters off Argentina.

High-res satellites are a cost-effective improvement over the way whale populations are currently calculated — narrowly limited counts from shore, a ship or a plane.

Scientists used the most powerful commercial observation platforms available can see surface features as small as 50 centimetres in black and white.

A test of the satellite’s image-recognition capacity, reported in the journal Plos One, detected about 90% of southern right whales swimming in the Golfo Nuevo on the coast of Argentina compared to a manual search of the imagery.

The accuracy surpasses previous attempts at space-borne assessment and could revolutionize the way whale populations are estimated.

“Our study is a proof of principle,” Peter Fretwell of the British Antarctic Survey told the BBC.

“But as the resolution of the satellites increases and our image analysis improves, we should be able to monitor many more species and in other types of location.

“It should be possible to do total population counts and in the future track the trajectory of those populations.”

For this study, Fretwell and his colleagues purchased a single, massive image taken in September 2012 by the WorldView2 satellite. The image covers 113 square kilometres including Golfo Nuevo, a circular gulf off the Argentine coast and an area where southern right whales are known to breed and raise their young from July through November.

By looking at the same image in different wavelengths, including one able to penetrate 15 metres beneath the ocean, the researchers were able to spot 55 probable whales and 22 possible whales in the gulf as well as 13 whale-shapes underwater.

“Satellite imagery provides much more accurate and wider coverage,” Fretwell told the Los Angeles Times. “If this works, we can take it out to many other species as well.”

These animals were driven to near-extinction in the early 20th century. Recognized as slow, shallow swimmers, they were the “right” whales to hunt.

For this reason, their numbers dropped from a pre-whaling population of 55,000-70,000 to just 300 by the 1920s.

“The same reason they are the right whales to catch makes them the right whales to look for by satellite,” said Fretwell.

Their numbers have seen something of a recovery, but without the means to carry out an accurate census, it is hard to know their precise status.

Scientists already have used satellite imagery to count populations of penguins in Antarctica, and Fretwell said similar work was being done with seals. The key to using satellites to track animals is not the size of the animal but how much it stands out from its environment, he said.

http://news.nationalpost.com/2014/02/14/high-resolution-satellites-revolutionize-whale-spotting-and-give-hope-for-imperiled-right-whale/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NPWorld+%28National+Post+-+World%29

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Grey reef sharks behave differently depending on the point in the lunar cycle, new research suggests.

THE DIVING BEHAVIOUR OF sharks appears to be influenced by the moon, water temperature and time of day, researchers have revealed.

A study of about 40 grey reef sharks, commonly found on coral reefs in northern Australia and the Indo-Pacific, found they stayed in deep water during a full moon and moved to shallow water with the new moon.

“To our knowledge, this is the first time such patterns have been observed in detail for reef sharks,” says lead researcher Gabriel Vianna, from the University of Western Australia (UWA) in Perth.

The sharks were tagged near Palau, east of the Philippines, and followed for two years. During this time, scientists from UWA and the Australian Institute of Marine Science recorded their movement and diving patterns.

The findings, published this week in the journal PLOS ONE, reveal that sharks descended to greater depths, and used a wider range of depths, around the time of the full moon.

Diving was also affected by seasonal changes, as the group, which mostly consisted of adult females, was recorded diving to an average depth of 35m in winter and 60m in spring.

In winter, the sharks remained closer to the surface, where the water was warmer. During summer, however, the sharks moved to a range of depths.

The researchers suggest that because sharks are cold blooded, they may prefer warmer water to conserve their energy. Warm water may also provide optimal conditions for foraging for food, the study says.

The findings also suggest that the time of day could affect how deeply sharks dive.

“We were surprised to see sharks going progressively deeper during the morning and the exact inverse pattern in the afternoon, gradually rising towards the surface,” says Gabriel, adding that the behaviour may relate to how much light is reflected on the reef at different times during the day.

Better knowledge of shark behaviour could help reduce the risk of sharks coming into contact with locals and tourists fishing, particularly if their diving behaviour can be predicted at certain times of the day.

“In places such as Palau, which relies heavily on marine tourism and where sharks are a major tourist attraction, the fishing of a few dozen sharks from popular dive sites could have a very negative impact on the national economy,” Gabriel says.

http://www.australiangeographic.com.au/journal/sharks-affected-by-full-moon.htm

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In a study recently published in PLoS ONE, researchers from from Charles University in the Czech Republic had 238 participants rate the faces of 80 students for trustworthiness, attractiveness, and dominance. Not surprisingly, they found that the three measures correlated well with each other, with faces rating high on one scale rating high on the other two. Female faces were generally more trustworthy than male ones. But that’s wasn’t all. A much more peculiar correlation was discovered as they looked at the data: brown-eyed faces were deemed more trustworthy than blue-eyed ones.

It didn’t matter if the judge was male or female, blue-eyed or brown-eyed. Even accounting for attractiveness and dominance, the result was the same: brown-eyed people’s faces were rated more trustworthy. There was some evidence of in-group bias, with blue-eyed female faces receiving lower ratings from brown-eyed women than from blue or green-eyed ones, but this difference didn’t drive the phenomenon. All the participants, no matter what eye color they had or how good-looking they thought the face was agreed that brown-eyed people just appear to look more reliable.

The real question is why? Is there a cultural bias towards brown eyes? Or does eye color really correlate somehow with personality traits like accountability and honesty? Does eye color really matter that much?

To find out, the scientists used computer manipulation to take the same faces but change their eye colors. Without changing traits other than hue of the iris, the researchers swapped the eye colors of the test faces from blue to brown and vice versa. This time, the opposite effect was found. Despite the strange correlation to eye color, the team found that eye color didn’t affect a photo’s trustworthiness rating. So it isn’t the eye color itself that really matters—something else about brown-eyed faces makes them seem more dependable.

To get at what’s really going on, the researchers took the faces and analyzed their shape. They looked at the distances between 72 facial landmarks, creating a grid-like representation of each face. For men, the answer was clear: differences in face shape explained the appeal of brown eyes.

Shape changes associated with eye color and perceived trustworthiness, from the grid-based facial shape analysis done by the researchers. Note the similarities between the shapes of brown-eyed faces and trustworthy ones.

“Brown-eyed individuals tend to be perceived as more trustworthy than blue-eyed ones,” explain the authors. “But it is not brown eyes that cause this perception. It is the facial morphology linked to brown eyes.”

Brown-eyed men, on average, have bigger mouths, broader chins, bigger noses, and more prominent eyebrows positioned closer to each other, while their blue-eyed brethren are characterized by more angular and prominent lower faces, longer chins, narrower mouths with downward pointing corners, smaller eyes, and more distant eyebrows. The differences associated with trustworthiness are also how our faces naturally express happiness—an upturned mouth, for example—which may explain why we trust people who innately have these traits.

Although the trend was the same for female faces, researchers didn’t find the same correlation between trustworthiness and face shape in women. This result is puzzling, but female faces were overall much less variable than male faces, so it’s possible the statistical analyses used to test for correlation were hampered by this. Or, it’s possible that something else is in play when it comes to the trustworthiness of female faces. The researchers hope that further research can shed light on this conundrum.

Given the importance of trust in human interactions, from friendships to business partnerships or even romance, these findings pose some interesting evolutionary questions. Why would certain face shapes seem more dangerous? Why would blue-eyed face shapes persist, even when they are not deemed as trustworthy? Are our behaviors linked to our bodies in ways we have yet to understand? There are no easy answers. Face shape and other morphological traits are partially based in genetics, but also partially to environmental factors like hormone levels in the womb during development. In seeking to understand how we perceive trust, we can learn more about the interplay between physiology and behavior as well as our own evolutionary history.

http://blogs.scientificamerican.com/science-sushi/2013/01/09/brown-eyes-deemed-more-trustworthy-but-thats-not-the-whole-story/

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Humpback whales are famed for their songs, most often heard in breeding season when males are competing to mate with females. In recent years, however, reports of whale songs occurring outside traditional breeding grounds have become more common. A new study may help explain why.

Humpbacks sing for their supper — or at least, they sing while they hunt for it.

The research, published December 19 in PLoS ONE, uncovers the whales’ little-understood acoustic behavior while foraging.

It also reveals a previously unknown behavioral flexibility on their part that allows the endangered marine mammals to balance their need to feed continuously with the competing need to exhibit mating behaviors such as song displays.

“They need to feed. They need to breed. So essentially, they multi-task,” said study co-author Ari S. Friedlaender, research scientist at Duke University’s Nicholas School of the Environment. “This suggests the widely held behavioral dichotomy of breeding-versus-feeding for this species is too simplistic.”

Researchers from the U.S. Naval Postgraduate School, the University of California-Santa Barbara and Duke tracked 10 humpback whales in coastal waters along the Western Antarctic Peninsula in May and June 2010. The peninsula’s bays and fjords are important late-season feeding grounds where humpbacks feast on krill each austral autumn before migrating to warm-water calving grounds thousands of miles away.

Using non-invasive multi-sensor tags that attach to the whales with suction cups, the researchers recorded the whales’ underwater movements and vocalizations as they foraged.

All 10 of the tags picked up the sounds of background songs, and in two cases, they recorded intense and continuous whale singing with a level of organization and structure approaching that of a typical breeding-ground mating display. The song bouts sometimes lasted close to an hour and in one case occurred even while sensors indicated the whale, or a close companion, was diving and lunging for food.

Humpbacks sing most frequently during breeding season, but are known to sing on other occasions too, such as while escorting mother-calf pairs along migratory routes. Though the reasons they sing are still not thoroughly understood, one distinction is clear: Songs sung in breeding grounds are quite different in duration, phrase type and theme structure from those heard at other locations and times.

“The fact that we heard mating displays being sung in late-season foraging grounds off the coast of Antarctica suggests humpback whale behavior may be more closely tied to the time of year than to physical locations. This may signify an ability to engage in breeding activities outside their traditional warm-water breeding grounds,” said Douglas P. Nowacek, Repass-Rogers University Associate Professor of Conservation Technology at Duke’s Nicholas School.

As the region’s climate warms, sea ice cover around the Western Antarctic Peninsula has thinned in recent years and the water stays open later in the foraging season, he explained. Whales are remaining there longer into austral autumn to feast on krill instead of heading off to warm-water breeding grounds, as many scientists previously believed.

“Mating may now be taking place at higher latitudes,” Nowacek said. “This merits further study.”

Alison K. Stimpert, research associate in oceanography at the Naval Postgraduate School, was lead author of the new study. Lindsey E. Peavey, a PhD Student at the University of California at Santa Barbara’s Bren School of Environmental Science and Management, co-authored it with Stimpert, Friedlaender and Nowacek.

Journal Reference:

1.Stimpert AK, Peavey LE, Friedlaender AS, Nowacek DP. Humpback Whale Song and Foraging Behavior on an Antarctic Feeding Ground. PLoS One, 2012 DOI: 10.1371/journal.pone.0051214

http://www.sciencedaily.com/releases/2012/12/121219174156.htm

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Stereotypes about male and female roles may influence the way we perceive depressed people.

It’s a well-known fact that men and women who behave the same way in the exact same situation—whether it’s a job interview, a cocktail party, or a traffic stop—are sometimes perceived and treated differently based on their gender.

Something similar, it seems, may happen when men and women start to show signs of depression. A new study, published this week in the journal PLoS ONE, suggests that people of both sexes are less likely to view men as being depressed and in need of professional help—even if a man’s symptoms are identical to a woman’s.

“A lot of attention has been paid to depression in women, and with good reason: Depression is twice as common in women,” says Dr. James B. Potash, the editor of the study and a professor of psychiatry at the University of Iowa, in Iowa City. “There has been relatively little focus on education about depression in men. This [study] emphasizes the importance of figuring out how to get through to men that depression can be disabling and treatment is important.”

Health.com: 12 Signs of Depression in Men

In the study, researchers in the U.K. asked a group of about 600 adults to read a short description of a hypothetical depressed person. This vignette, which was designed to illustrate the diagnostic criteria for clinical depression (also known as major depression), read in part:

For the past two weeks, Kate has been feeling really down. She wakes up in the morning with a flat, heavy feeling that sticks with her all day. She isn’t enjoying things the way she normally would. In fact, nothing gives her pleasure. Even when good things happen, they don’t seem to make Kate happy.

Fifty-seven percent of the study participants recognized Kate’s symptoms—which also included difficulty concentrating, fatigue, and insomnia—as indications of a mental health disorder, and more than three-quarters of those people correctly identified the disorder as depression. Only 10% of the respondents said Kate did not have a problem.

The researchers presented the same vignette to another group of 600 people. This time, however, every mention of “Kate” was replaced by “Jack,” and all the pronouns were switched from female to male. Those minor changes had a noticeable effect: Though nearly as many people recognized Jack as having a mental health problem (52%), more than twice as many as in the Kate scenario said he did not (21%).

In addition, men themselves were less likely than women to label Jack depressed—a pattern that was not seen with Kate.

Health.com: How to Help Someone Who’s Depressed

Why the difference? Male stereotypes that emphasize traits such as toughness and strength may dissuade both women and men, and especially the latter, from identifying or acknowledging the signs of depression in men, says study author Viren Swami.

“Men are expected to be strong, deny pain and vulnerability, and conceal any emotional fragility,” says Swami, a psychologist at the University of Westminster, in London. “Because of these societal expectations, men appear to have poorer understanding of mental health and aren’t as good at detecting symptoms of depression compared with women.”

Potash says the findings also may reflect the fact that women are generally more attuned to emotions and better at articulating them. Some men might have all the outward signs of depression, and yet when asked about their mood they “may not be able to say much more than ‘I don’t know,’” he says. “A substantial minority of men just don’t describe depression.”

Health.com: 10 Careers With High Rates of Depression

On a deeper level, men’s failure to recognize the symptoms of depression in a fellow male may represent a kind of defense mechanism prompted by an “unconscious identification” with that man, says Dr. Radu Saveanu, a professor of psychiatry at the University of Miami Miller School of Medicine.

“They may think, ‘If this guy is having trouble and may need treatment, I may be in the same position someday,’” says Saveanu, who was not involved in the study. “That anxiety distorts the ability to be more objective.”

All of these dynamics may affect the likelihood of seeking or recommending treatment. In the study, men were more likely than women to recommend that Kate seek professional help, but this gap disappeared in the Jack scenario. Men also expressed less sympathy for Jack than women did.

The reluctance to seek treatment isn’t unique to men, but it does reflect an independent-minded streak that is more common among males, Potash says. Men tend to think that pulling themselves out of depression is “something they ought to be able to do,” he says. “It’s the stereotype of men who never ask for directions. They won’t admit that they can’t take care of it themselves.”

Health.com: Depressed? 12 Mental Tricks to Turn It Around

Gender, of course, isn’t the only factor that shapes how we view depression symptoms. Swami also found that respondents of either sex who held negative attitudes towards psychiatry and science felt that both Kate and Jack’s symptoms were less distressing, more difficult to treat, and less worthy of sympathy or professional help.

Swami took these trends into account, but he can’t rule out that other factors might have influenced the gender differences seen in the study. The participants’ own mental health history was unknown, for instance, though Swami says previous diagnoses do not tend to impact “mental health literacy,” or how well people understand mental health issues.

Future research will need to address these limitations, he says.

Read more: http://healthland.time.com/2012/11/15/how-gender-stereotypes-warp-our-view-of-depression/#ixzz2Es26tBvB

 

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Carp stored in large tubs at Czech Christmas markets align themselves in the north-south direction, suggesting they possess a previously unknown capacity to perceive geomagnetic fields, according to a new study published December 5 in the open access journal PLOS ONE, led Hynek Burda from the University of Life Sciences (Prague), Czech Republic and colleagues from other institutions.

Their study included over 14,000 fish in 25 markets, and the majority of these fish were found to align themselves along the north-south axis. The fish were accustomed to human onlookers, and street lights and other potential disturbances seemed to have no effect on the orientation of the fish.

In the absence of other common stimuli for orientation like light, sound or the flow of water, the authors suggest that the fish most likely align themselves to geomagnetic cues.

http://www.sciencedaily.com/releases/2012/12/121205200057.htm

Stuck at work? Having trouble finishing out your Friday? Take a good, long look at this bunny. It’s adorable. And, according to newly published research, it could actually improve your performance at work*.

Researchers from Hiroshima University in Japan describe the results of their study in the latest issue of PLoS ONE. We’ve preserved the researchers’ description verbatim where possible, including explanations only when necessary, because there’s something unequivocally excellent about reading things like “cuteness-triggered positive emotion” in peer-reviewed scientific research:

In this study, three experiments were conducted to examine the effects of viewing cute images on subsequent task performance. In the first experiment, university students performed a fine motor dexterity task [participants played Bilibili Dr. Game, basically the Japanese version of Operation] before and after viewing images of baby [“cute images”] or adult [“less cute”] animals. Performance… increased after viewing cute images more than after viewing images that were less cute.

In the second experiment, this finding was replicated by using a non-motor visual search task. [This involved counting the number of times a specified number appeared in successive 40-digit groupings. For example, a subject presented with the numbers on the left would be asked to identify, as quickly as possible, how many times the number 8 appeared in the group. Test participants completed as many of these number groups as possible in a three minute period.] Performance improved more after viewing cute images than after viewing less cute images. Viewing images of pleasant foods was ineffective in improving performance. 

In the third experiment, participants performed a global–local letter task after viewing images of baby animals, adult animals, and neutral objects.

A quick explanation here: in a global-local letter task, participants are asked to indicate, as quickly as possible, whether a stimulus contains the letter “H” or letter “T” by pressing left or right on a response pad. Sounds easy, but the task actually requires a fair bit of concentration, as sometimes the letter the participant is looking for is actually composed of a series of other letters (an example is the big “H,” pictured at left, built out of smaller, closely spaced “F”s. This is an example of a global target stimulus); while other times, the letter they’re looking for is spelling out a larger letter (the big “L” on the left is built out of smaller, closely spaced “T”s. This is an example of a localtarget stimulus). Alright, back to the findings:

In general, global features were processed faster than local features. However, this global precedence effect was reduced after viewing cute images.

Results show that participants performed tasks requiring focused attention more carefully after viewing cute images. This is interpreted as the result of a narrowed attentional focus induced by the cuteness-triggered positive emotion… For future applications, cute objects may be used as an emotion elicitor to induce careful behavioral tendencies in specific situations, such as driving and office work.

http://io9.com/5947360/study-of-the-decade-looking-at-photos-of-cute-animals-linked-to-increased-work-performance