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Topics - ABM Nazmul Islam

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31
Some ancient lizards’ bad luck has become a gold mine of information for scientists.

Reptilian remains in roughly 99-million-year-old amber provide unusually detailed insight into the evolutionary history of lizards, researchers report March 4 in Science Advances.

The 12 chunks of amber, originally collected in Myanmar, contain parts of lizards that got trapped in tree resin during the Cretaceous period. Unlike stone, amber can fossilize small, delicate animals, as well as preserve soft tissues and organs.

Some of the amber specimens contain just a lizard leg; one holds most of a tongue. A translucent layer of scales traces where one lizard’s body once lay (left panel in the image above). In another fossil (middle panel), which contains skin and unusually long claws, sediment snuck into the lizard’s body during fossilization and created a mold of some bones. The researchers used CT scans to observe these internal structures in three dimensions.


ANCIENT BABY This fossil of a newborn lizard might belong to the oldest known relative of modern chameleons, researchers say.
DAVID GRIMALDI

Amber-encased toe pads (right panel) identified a few of the lizards as gecko ancestors. One of the preserved lizards may represent an intermediate form between known older relatives and modern geckos, the team says.

The skin and skeleton of a newborn lizard just over a centimeter long (shown in the image below) is the most surprising fossil in the bunch, says study coauthor Juan Daza, a herpetologist at Sam Houston State University in Huntsville, Texas. A stout skull, big eye sockets and a short, curled tail suggest that the young lizard could be the oldest known relative of modern chameleons.

32
Faculty Sections / These beetles use surface tension to water-ski
« on: March 09, 2016, 12:01:33 PM »
Waterlily beetles (Galerucella nymphaeae) literally fly across water, high speed videography and a bit of mathematical modeling reveals.

The beetles have a combination of hydrophobic hairs that line their legs and hydrophilic claws that grip the surface of water without getting too wet. Prior to “take off,” the insects lift their middle pair of legs. Then, the insects beat their wings extremely fast and fly horizontally across a pool of water. It looks a lot like water-skiing.


In lab tests, waterlily beetles reached 0.5 meters per second — without an active brake system. Surface tension keeps the insects afloat, they found. The insects create ripples in the water, which generates drag at speeds greater than 0.23 meters per second (more drag than when the beetles just fly through air). Thus, for these beetles, skiing across a pond at breakneck speeds costs a lot of energy and requires greater wing thrust than normal flying. However, this mode of getting around could be more advantageous for foraging and  help them avoid underwater predators like fish, the researchers speculate March 2 in the Journal of Experimental Biology.

33
Faculty Sections / Historian puts new spin on scientific revolution
« on: March 09, 2016, 12:01:03 PM »
When Columbus discovered America, European culture hadn’t yet grasped the concept of discovery. Various languages had verbs that could be translated as discover, but only in the sense of discovering things like a worm under a rock. Scholars operated within a worldview that all knowledge had been articulated by the ancients, such as Ptolemy, the astronomer who compiled the mathematical details of the Earth-centered universe. As it happened, Ptolemy was also the greatest of ancient geographers. So when Columbus showed that Ptolemy’s grasp on geography was flawed, it opened the way for Copernicus to challenge Ptolemy on his picture of the cosmos as well. Deep thinkers who were paying attention then realized that nature possessed secrets for humankind to “discover.”

“The existence of the idea of discovery is a necessary precondition for science,” writes historian David Wootton. “The discovery of America in 1492 created a new enterprise that intellectuals could engage in: the discovery of new knowledge.”

Appreciating the concept of discovery was not enough to instigate the invention of science. The arrival of the printing press in the mid-15th century was also especially essential. It standardized and magnified the ability of scholars to disseminate knowledge, enabling the growth of communities, cooperation and competition. Late medieval artists’ development of geometrical principles underlying perspective in paintings also provided important mathematical insights. Other key concepts (like discovery) required labeling and clarifying, among them the idea of “evidence.”

And modern science’s birth required a trigger, a good candidate being the supernova observed by Tycho Brahe in 1572. Suddenly, the heavens became changeable, contradicting the Aristotelian dogma of eternal changeless perfection in the sky. Tycho’s exploding star did not cause the scientific revolution, Wootton avers, but it did announce the revolution’s beginning.

In The Invention of Science, Wootton incorporates these insights into an idiosyncratic but deeply thoughtful account of the rise of science, disagreeing frequently with mainstream science historians and philosophers. He especially scorns the relativists who contend that different scientific views are all mere social constructions such that no one is better than any other. Wootton agrees that approaches to science may be socially influenced in their construction, but nevertheless the real world constrains the success of any given approach.

Wootton’s book offers a fresh approach to the history of science with details not usually encountered in the standard accounts. It might not be the last or even best word in understanding modern science’s origins or practice, but it certainly has identified aspects that, if ignored, would leave an inadequate picture, lacking important perspective.

Buy The Invention of Science from Amazon.com. Reviews on the Science News website include Amazon.com links that generate funds for Society for Science & the Public programs.

34
Faculty Sections / Mind’s healing powers put to the test in new book
« on: March 09, 2016, 12:00:34 PM »
In a wide-ranging and compelling new book, science journalist Jo Marchant explores whether the mind can heal the body. The question is polarizing: Conventional doctors dismiss the power of the mind as New Age hooey, while alternative medicine advocates are quick to claim miracle cures for whatever ails you. The murky middle ground between these poles is where Marchant lingers.

Inflammation, blood sugar and breathing rate can all influence mood, and it seems mood may influence those processes right back, Marchant argues. Those blurred boundaries cloud Descartes’ old distinction between mind and body, integrating the two so tightly that “it is impossible to consider one without the other,” she writes.

With lively, clear prose, Marchant surveys the evidence for the mind-body connection. One of the most compelling arguments comes from the placebo effect. A surge of the chemical messenger dopamine floods the brains of people with Parkinson’s disease after they receive a placebo, mimicking the effects of a drug, for instance. Placebos can help even when people know they’re taking a fake. After forking over money for inert capsules from an online vendor, Marchant found that the pills eased her headache in 20 minutes. That experience was admittedly nonscientific, but Marchant draws from plenty of studies to make the case that something interesting — and potentially powerful — lurks in placebos (SN: 2/22/14, p. 12).

Throughout Cure, Marchant uses deeply reported stories of patients and researchers to raise questions about the status quo of health care. These stories reveal that simple changes that soothe people’s psychological states may lead to better outcomes. Terminal cancer patients who talked with palliative care specialists focused on quality of remaining life, rather than medical care, had less depression and better experiences than patients who didn’t get such care, a small study found. These patients also lived nearly three months longer. “We are humans, not machines, after all,” Marchant writes. “When we’re receiving medical care, our mental state matters.”

Other research makes the case that the mind is a strong ally in the quest for health: Studies of hypnotherapy for people suffering from irritable bowel syndrome, virtual reality snow worlds for burn victims and comforting talk for women undergoing breast biopsies all make clear that the mind can have a powerful effect on the body. And as Marchant argues, that’s a realization that matters.

Buy Cure from Amazon.com. Reviews on the Science News website include Amazon.com links that generate funds for Society for Science & the Public programs.

35
Faculty Sections / Free virtual fossils for everyone
« on: March 09, 2016, 12:00:04 PM »
At MorphoSource.org, playing with fossils is not only allowed, it’s encouraged. The online database is home to oodles of digital 3-D scans of bones from both extinct and modern-day creatures. Anyone with an Internet connection is free to peruse the images, manipulate and rotate specimens and even download instructions to 3-D print them.

So far, scientists have contributed images representing over 200 genera. Among the newest uploads are fossils of the recently discovered Homo naledi, the controversial species that may be at the base of the human genus (SN: 10/3/15, p. 6). MorphoSource’s collection is primate-heavy, but users will also find scans of other mammals, reptiles, fish and even insects.

The website, funded by Duke University and the National Science Foundation, offers several ways to search for specimens, such as by taxonomy. But those unfamiliar with animals’ Latin names may find the database difficult to navigate. Still, MorphoSource is a great resource for anyone who’s always wanted to get their hands on some fossils.

36
Faculty Sections / Mercury’s dark secret revealed
« on: March 09, 2016, 11:59:25 AM »
Ever since Mariner 10 flew by Mercury in 1974 and 1975, researchers have known that the planet was darker than the moon. But they didn’t know why.

Some of the moon’s darkness comes from its iron-rich minerals, but those are lacking on Mercury. Scientists suspected that graphite might color Mercury, but they had no proof — until now. NASA’s MESSENGER spacecraft, which spent four years orbiting Mercury before intentionally crashing last April (SN Online: 4/30/15), got close enough to obtain neutron spectroscopy data from a few dark patches in and around craters. Those patches are slathered with carbon, probably from a subsurface primordial crust, researchers report online March 7 in Nature Geoscience.

The crater carbon was probably churned up from a layer of graphite. A steady rain of meteorites and volcanic activity mixed this graphite into Mercury’s topsoil, darkening the entire planet, suggest Patrick Peplowski, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and colleagues.

37
Faculty Sections / Parasites help brine shrimp survive toxic waters
« on: March 09, 2016, 11:58:52 AM »
Being infected with a parasite is usually not good news. Some of the critters can make you sick, and some will eventually kill you. And studies have found that when an animal has to deal with both a parasite and pollutants such as toxic heavy metals, the stressors add up.

But that isn’t true for Artemia brine shrimp in Spain, a new study finds. Infection with cestodes — a type of parasitic flatworm also known as tapeworms — results in an increased ability to survive in waters laced with toxic arsenic.

Marta Sánchez of the Spanish National Research Council in Seville has been studying the role of parasites in ecosystems. She and her colleagues were curious about the brine shrimp because they are key players in the ecosystem; they are eaten by many water birds, including flamingos, and can ferry pollutants and parasites into the birds. “Infected [brine shrimp] are more susceptible to predation by birds,” Sánchez notes, which contributes to pollutant levels in the birds.


Brine shrimp infected with tiny tapeworms turn red, which probably makes them more susceptible to being eaten by birds.
M.I. SANCHEZ ET AL/PLOS PATHOGENS 2016 (CC-BY 4.0)
When brine shrimp become infected with parasites, they turn red. This makes them especially attractive to birds not only because they are easier to see but also because birds are on the lookout for the carotenoid pigments responsible for the color. These pigments not only give a bird’s feathers their colors but they are also necessary for a healthy bird. “As birds cannot synthesize these pigments and they are a scarce resource in nature, they selectively search for them in their diet,” Sánchez says.

The red color also makes it easy for scientists to pick out infected brine shrimp. Sánchez and her colleagues collected brine shrimp from southwestern Spain’s Odiel and Tinto estuary, which is tainted with arsenic and other heavy metals from current and past mining activities. In the lab, the researchers separated the parasite-infected and uninfected brine shrimp and then ran tests to see how well they survived in arsenic-laced waters.

As the concentration of arsenic in the water increased, so did the number of brine shrimp that died. But more brine shrimp that were infected with cestodes survived than uninfected ones, the team reports March 3 in PLOS Pathogens. Then, curious about the effects of climate change, the researchers repeated their experiment with warmer water. Again, the parasites appeared to confer some level of protection to the brine shrimp.

It may not be obvious, but causing a quick death is not a good strategy for a parasite. That’s because a parasite needs its host to stay alive long enough for the parasite to reproduce, leave and find a new host. If the host dies too quickly, then the parasite dies with it. So for cestodes, giving brine shrimp some help in surviving polluted waters may be in the parasites’ best interest.

The results suggests that the cestodes help change the way the brine shrimp deal with pollutants and the resulting stress. When the researchers compared infected and uninfected brine shrimp, they found differences in the antioxidant defenses that protect an organism against the damaging effects of reactive oxygen species. “Infected individuals were better than uninfected individuals at coping under polluted conditions,” Sánchez says. Also, infected brine shrimp had higher amounts of lipid droplets that are thought to sequester toxins.

The researchers can’t say whether this beneficial relationship is restricted to this particular estuary in Spain. “What we can say,” Sánchez says, “is that the red coloration associated with tapeworm infections is something we have observed in many sites in different countries. Hence, we expect our results do represent what would be recorded at other localities.”


38
Using records of ships wrecked by Atlantic hurricanes dating as far back as the days of Christopher Columbus, researchers have extended the hurricane record by hundreds of years. The work reveals that hurricane frequency plummeted 75 percent between 1645 and 1715, a time called the Maunder Minimum when the sun dimmed to its lowest recorded brightness.

“We didn’t go looking for the Maunder Minimum; it just popped out of the data,” says study coauthor Valerie Trouet, a paleoclimate scientist at the University of Arizona in Tucson.

The findings should help scientists better predict how hurricanes will behave under climate change, the researchers report in a paper to appear in the Proceedings of the National Academy of Sciences.Detailed hurricane observational records go back to 1851. Scouring an Atlantic shipwreck catalog, Trouet and colleagues identified more than 650 Spanish ships sunk by hurricanes from 1495 through 1825. The researchers bridged the shipwreck and observational records using tree rings from slash pines (Pinus elliottii) collected along the Florida coast and dating to as early as 1707. Hurricane damage stunts tree growth, narrowing the annual rings. All three records agreed, allowing the researchers to stitch together one long hurricane frequency record.

The number of hurricane-caused shipwrecks during the Maunder Minimum, which makes up a large portion of a period nicknamed the “Little Ice Age,” was less than a third the number of wrecks in the preceding decades. A hurricane slowdown during the solar dim period makes sense, Trouet says. Warm seawater fuels hurricanes. As temperatures dropped around the Maunder Minimum, less heat was available to power storms.

The finding doesn’t mean that global warming will increase hurricane frequency, says Gabriel Vecchi, an oceanographer at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton, N.J. While both solar brightness and heat-trapping greenhouse gases cause warming, their effects on hurricanes “aren’t perfect analogs,” he says.

Still, the new data can provide a test for climate simulations, Vecchi says. “We can ask a model, ‘When we give you less sun, what do you do?’ If it doesn’t give us fewer hurricanes, we can then ask why. This gives us something to aim at.”

39
Faculty Sections / Olive oil untangles plastic
« on: March 09, 2016, 11:57:34 AM »
Chefs often add olive oil to spaghetti. Now a study finds that olive oil and other vegetable oils can also help make one type of fiber — essentially plastic spaghetti — super-strong. Researchers stumbled onto using the oils on plastic while trying to develop a better type of wax for skis. And those oils can not only keep those fibers from getting tangled, but are also safer and better for the environment than the solvents normally used for this purpose. The new oil-treated fibers could find a use in products such as bulletproof fabrics or ropes that anchor offshore oil rigs.

40
Over the ground lies a mantle of white — on Pluto. Snow-capped peaks on the dwarf planet dot an otherwise ruddy terrain. But these snowy summits appear to be composed of methane, not water, researchers report online March 3.

Mountain tops in Pluto’s Cthulhu Regio, a dark landscape abutting the planet’s famous heart, reflect more light than the surrounding area. The New Horizons spacecraft, which flew past Pluto on July 14, found that the bright regions correspond to surface deposits of methane. Mission scientists speculate that perhaps methane in the atmosphere on Pluto behaves like water in the air on Earth, building up on the ground as frost at the highest (and coldest) elevations.

41
Faculty Sections / Psychology’s replication crisis sparks new debate
« on: March 09, 2016, 11:56:24 AM »
Psychology got rocked last year by a report that many of the field’s published results vanish in repeat experiments. But that disturbing study sounded a false alarm, a controversial analysis finds.

The original investigation of 100 studies contained key errors, contend Harvard University psychologist Daniel Gilbert and his colleagues. After correcting for those errors, the effects reported in 85 of those studies appeared in replications conducted by different researchers. So an initial conclusion that only 35 studies generated repeatable findings was a gross underestimate, Gilbert’s team reports in the March 4 Science.

“There’s no evidence for a replication crisis in psychology,” Gilbert says.

Psychologist Brian Nosek of the University of Virginia in Charlottesville and other members of the group who conducted the original replication study (SN: 10/3/15, p. 8) reject Gilbert’s analysis. The 2015 report provides “initial, not definitive evidence” that psychology has a reproducibility problem, they write in a response published in the same issue of Science.

Strikingly, “the very best scientists cannot really agree on what the results of the most important paper in the recent history of psychology mean,” says Stanford University epidemiologist John Ioannidis. Researchers’ assumptions and expectations can influence their take on any results, “no matter how clear and strong they are.”

Many repeat studies in the 2015 paper differed dramatically from initial studies, stacking the deck against achieving successful replications, Gilbert says. Replications often sampled different populations, such as substituting native Italians for Americans in a study of attitudes toward black Americans. Many altered procedures. One replication effort gave older children the relatively easy task of locating items on a small computer screen, whereas the original study gave younger children a harder task of locating items on a large computer screen.

Repeat studies also generally included too few volunteers to make a statistically compelling case that a replication had succeeded or failed, Gilbert says. Another problem was that each original study was replicated only once. Multiple repeats of a study balance out differences in study procedures and increase the number of successful replications, the scientists argue.

In a replication study that often amounted to a comparison of apples and oranges, at least 34 replication studies should have failed by chance, assuming all 100 original studies described true effects, Gilbert and his colleagues estimate. That makes the new estimate of 85 successful replications even more impressive, they say.

Nosek’s group calculates that only about 22 replication attempts in the 2015 study should have failed by chance. Tellingly, Nosek says, even successful replications found weaker statistical effects than the original studies had. Published studies make statistically significant findings look unduly strong, he says. Journals usually don’t publish replication failures and many researchers simply file them away.

Another new analysis of Nosek’s group’s work suggests that replication study samples need to be beefed up before any conclusions can be made about the durability of psychology results. Failures to replicate in the 2015 investigation largely occurred because many original studies contained only enough participants to generate weak but statistically significant effects, two psychologists assert February 26 in PLOS ONE. Journals’ bias for publishing only positive results also contributed to replication failures, add  Alexander Etz, at the University of Amsterdam at the time of the study, and Joachim Vandekerckhove of the University of California, Irvine.

The pair statistically analyzed 72 papers and replication attempts from Nosek’s project. Only 19 original studies contained enough volunteers to yield a strong, statistically significant effect. Nosek’s team needed many more studies with comparably large sample sizes to generalize about the state of replication in psychology, the researchers say.

Researchers in psychology and other fields need to worry less about reproducing statistically significant results and more about developing theories that can be tested with a variety of statistical approaches, argues psychologist Gerd Gigerenzer of the Max Planck Institute for Human Development in Berlin. Statistical significance expresses the probability of observing a relationship between two variables — say, a link between a change in the wording of a charitable appeal and an increase in donations — assuming from the start that no such relationship actually exists. But researchers rarely test any proposed explanations for statistically significant results.

Pressures to publish encourage researchers to tweak what they’re studying and how they measure it to ensure statistically significant results, Gigerenzer adds. Journals need to review study proposals before any experiments are run, in order to discourage such “borderline cheating,” he recommends.

42
Radiation from the 2011 disaster at the Fukushima Daiichi nuclear power plant contaminates most Japanese seafood at low levels, researchers estimate February 29 in the Proceedings of the National Academy of Sciences.

For aquatic foods, data on lingering concentrations of cesium is limited in terms of the number of species sampled and the levels that surveys can even detect. To fill in the blanks, a team of researchers in Japan drew from survey measurements from April 2011 to September 2015 and devised a way to predict cesium contamination in different aquatic species across Japan.

The analysis provides mixed news: Overall, cesium contamination is pretty low. But, some species retain higher levels than others. Larger fish near the top of the food web tended to have the highest levels of contamination. The researchers predict that such factors put some wild freshwater species like the whitespotted char (Salvelinus leucomaenis leucomaenis) and the Japanese eel (Anguilla japonica) at higher risk for contamination.

43
Faculty Sections / Microcephaly: Building a case against Zika
« on: March 09, 2016, 11:55:13 AM »
The prime suspect in Brazil’s recent surge in birth defects may be convicted this summer, in the sweltering cities of Colombia.

That’s when the first big wave of pregnant women infected with Zika virus last fall will begin to give birth. Whether or not these babies are born with stunted brains, a condition known as microcephaly, may offer the best evidence yet that Zika is the culprit — or not.

While the world waits, molecular evidence is starting to come in. Zika virus readily infects (and kills) one kind of brain cell in developing embryos, researchers report online March 4 in Cell Stem Cell. “It’s the first step to show that Zika is actually doing something in the brain,” says study coauthor Guo-Li Ming, a neuroscientist from Johns Hopkins School of Medicine. Previous studies have found traces of Zika in damaged fetal brains — but that’s just a correlation.

ABNORMALLY SMALL Babies with microcephaly have head circumferences that are two standard deviations below average (middle). Three standard deviations below average is considered severe microcephaly (bottom).
CDC

Still, correlations like these may be why the mosquito-borne virus has sparked so much panic. In the last year, Zika has torn through Brazil and invaded 40 other countries and territories. Now, Zika infection during pregnancy is the leading theory for why so many babies have been born with microcephaly in Brazil. Suspected cases of the rare birth defect are showing up at more than 30 times the rate of previous years.

Seeing microcephaly numbers skyrocket in other countries could make or break the case. So far, only Brazil has reported an uptick in microcephaly (though French Polynesia did in an earlier outbreak). Still, evidence that Zika is to blame remains circumstantial.

“We don’t have absolute proof,” says Christopher Dye, a strategy director of the World Health Organization. But scientists do have enough evidence to consider the virus “guilty until proven innocent,” he says.

University of Pittsburgh public health researcher Ernesto Marques agrees. “We have a victim, and we have a suspected criminal with a gun.” Now, he says, “we have to prove who pulled the trigger.”

44
Faculty Sections / Cancer moonshot’ launch prep under way
« on: March 09, 2016, 11:54:38 AM »
When President Barack Obama called for a “cancer moonshot” during his State of the Union address, the idea was big on vision and low on specifics. The goal, he said, was to make America “the country that cures cancer once and for all.” Now, details are trickling out, but a true plan for launch won’t be ready until June.

In February, the White House released a list of cancer research areas to target. Many of those, such as therapeutic vaccines and cancer genomics, are already the subject of intense research. The administration also announced that the “moonshot initiative will begin immediately with $195 million in new cancer activities at the National Institutes of Health” this year. Not all of that money is moonshot money, though.

At a meeting on February 24 of the National Cancer Advisory Board, National Cancer Institute acting head Doug Lowy noted that $55 million of it was earmarked to jump-start the new cancer initiative. The rest would be divvied up among new research project grants ($80 million), given to 21 cancer research institutions ($10 million), and cover such costs as rent and utilities ($50 million).

More money may be in the pipeline. The president’s proposed 2017 budget (which will face congressional hurdles) includes an extra $680 million for NCI, plus $75 million for the Food and Drug Administration to try to speed the progress of cancer clinical trials.

It’s not known how this new funding would be divvied up. A to-be-named panel of advisers will presented recommendations in June.

45
Faculty Sections / These beetles use surface tension to water-ski
« on: March 09, 2016, 11:54:00 AM »
Waterlily beetles (Galerucella nymphaeae) literally fly across water, high speed videography and a bit of mathematical modeling reveals.

The beetles have a combination of hydrophobic hairs that line their legs and hydrophilic claws that grip the surface of water without getting too wet. Prior to “take off,” the insects lift their middle pair of legs. Then, the insects beat their wings extremely fast and fly horizontally across a pool of water. It looks a lot like water-skiing.


In lab tests, waterlily beetles reached 0.5 meters per second — without an active brake system. Surface tension keeps the insects afloat, they found. The insects create ripples in the water, which generates drag at speeds greater than 0.23 meters per second (more drag than when the beetles just fly through air). Thus, for these beetles, skiing across a pond at breakneck speeds costs a lot of energy and requires greater wing thrust than normal flying. However, this mode of getting around could be more advantageous for foraging and  help them avoid underwater predators like fish, the researchers speculate March 2 in the Journal of Experimental Biology.

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