Astronomy
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Ancient Volcanos On Mars Burned Very, Very Hot
Mars' past may have seen a lot of very high-temperature volcanism. Similar to the Mount Helen’s eruption of 1980, Mars’ volcanoes would have an abundance of high-temperature and high-silica magma that erupted and then formed newly discovered minerals found in Gale crater.
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It is thought that volcanism on Mars is not as frequent as on Earth, but when there are eruptions they are very violent. The last one is believed to have taken place 20 million years ago. As there are no tectonic plates, the “hotspots” of volcanic activity remain fixed on the Martian surface, as evident by the Tharsis bulge. This volcanic activity is thought to come from melting hot mantle plumes under the Martian crust.
Utilizing the X-ray diffraction instrument on NASA’s Curiosity rover, Morris and his team found traces of the mineral tridymite in a drill site in Gale crater. Tridymite is normally only associated with silica-rich volcanism that can have explosive and high-temperature eruptions similar to the volcanism seen in the Cascades on Earth, says Morris.
“This mineral forms only at temperatures greater than about 900 degrees Centigrade,” Morris says. “So it was a real shock to us that what we may have here is a marker for a different kind of volcanism on Mars.”
Most silica-rich volcanism is due to Earth’s plate tectonics diving into water in the crust. Because of this, the basalt forms these silica-rich and high-temperature magmas that then erupt from the volcanoes, says Morris. As there are no observable plate tectonics that exist on Mars, Morris and his team do not know what truly caused these minerals to form.
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Earth Has An Almost-Moon
Earth has a small companion that NASA is calling an almost-Moon. The small asteroid, called 2016 H03, isn’t quite a moon because it’s actually orbiting the Sun. In its orbit around the Sun, it spends about half of its time closer to the Sun than the Earth.
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2016 H03’s orbit is tilted relative to Earth’s, and it passes through the plane of Earth’s orbit. Over the decades, it also performs a slow, back and forth twist. NASA describes 2016 H03’s orbit as a game of leap frog.
“The asteroid’s loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth’s gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon,” said Chodas. “The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth.”
Earth’s little quasi-moon has been in its stable orbit for about a century, according to calculations, though it was only spotted on April 27th, 2016, by the Pan-STARRS 1 asteroid survey telescope in Hawaii. Pan-STARRS 1 is operated by the University of Hawaii’s Institute for Astronomy and NASA’s Planetary Defense Coordination Office. (Did you know we had a Planetary Defense Coordination Office?)
2016 H03 is small. It’s exact size has not been established, but it’s between 40 and 100 meters (120 and 300 ft.) It’s been around a century, and calculations say it will be around for centuries more.
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Biology
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At Any Skill Level, Making Art Reduces Stress Hormones
Whether you're Van Gogh or a stick-figure sketcher, a new Drexel University study found that making art can significantly reduce stress-related hormones in your body.
Although the researchers from Drexel's College of Nursing and Health Professions believed that past experience in creating art might amplify the activity's stress-reducing effects, their study found that everyone seems to benefit equally.
"It was surprising and it also wasn't," said Girija Kaimal, EdD, assistant professor of creative arts therapies. "It wasn't surprising because that's the core idea in art therapy: Everyone is creative and can be expressive in the visual arts when working in a supportive setting. That said, I did expect that perhaps the effects would be stronger for those with prior experience."
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"Biomarkers" are biological indicators (like hormones) that can be used to measure conditions in the body, such as stress. Cortisol was one such the hormone measured in the study through saliva samples. The higher a person's cortisol level, the more stressed a person is likely to be. For Kaimal's study, 39 adults, ranging from 18 to 59 years old, were invited to participate in 45 minutes of art-making. Cortisol levels were taken before and after the art-making period.
Materials available to the participants included markers and paper, modeling clay and collage materials. There were no directions given and every participant could use any of the materials they chose to create any work of art they desired. An art therapist was present during the activity to help if the participant requested any. Of those who took part in the study, just under half reported that they had limited experience in making art.
The researchers found that 75 percent of the participants' cortisol levels lowered during their 45 minutes of making art. And while there was some variation in how much cortisol levels lowered, there was no correlation between past art experiences and lower levels.
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The Indris Have Got Rhythm!
Timing And Pitch Variation Of A Primate Song Examined Between Sexes And Age Classes
A crucial, common feature of speech and music is that they show non-random structures over time. It is an open question which of the other species share rhythmic abilities with humans, but in most cases the lack of knowledge about their behavioral displays prevents further studies. Indris are the only lemurs who sing. They produce loud howling cries that can be heard at several kilometers, in which all members of a group usually sing. We tested whether overlapping and turn-taking during the songs followed a precise pattern by analysing the temporal structure of the individuals' contribution to the song. We found that both dominants (males and females) and non-dominants influenced the onset timing one another. We have found that the dominant male and the dominant female in a group overlapped each other more frequently than they did with the non-dominants. We then focused on the temporal and frequency structure of particular phrases occurring during the song. Our results show that males and females have dimorphic inter-onset intervals during the phrases. Moreover, median frequencies of the unit emitted in the phrases also differ between the sexes, with males showing higher frequencies when compared to females. We have not found an effect of age on the temporal and spectral structure of the phrases. These results indicate that singing in indris has a high behavioral flexibility and varies according to social and individual factors. The flexible spectral structure of the phrases given during the song may underlie perceptual abilities that are relatively unknown in other non-human primates, such as the ability to recognize particular pitch patterns.
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Chemistry
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Groovy Chemistry: The Materials Science Behind Records
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In 1905, Thomas Edison was the defendant in a lawsuit over the composition of wax cylinders used as recording media. Several inventions in recording predate these cylinders, but the 1905 lawsuit reveals many of the key considerations in developing quality materials for an emerging record industry.
The waxes in question are more accurately described as metal soaps, fatty acid chains stuck together with the help of metal ions. A stylus can glide over the soft soaps without hitting hard bumps or grains that would produce audible crackles and pops. Yet the materials are substantial enough to maintain their grooves after being played repeatedly.
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Lon J. Mathias, a polymer chemist and professor emeritus at the University of Southern Mississippi, offers another reason for why vinyl came to dominate records. “It’s cheap, and it’s easily molded,” he says. Although he can’t speak to the specific composition of today’s vinyl, he does share some general insights into the plastic.
PVC is mostly amorphous, but by a happy accident of the free-radical-mediated reactions that build polymer chains from smaller subunits, the material is 10 to 20% crystalline, Mathias says. As a result, PVC has enough structural fortitude to support a groove and stand up to a record needle without compromising smoothness. Without any additives, PVC is clear-ish, Mathias says, so record vinyl needs something like carbon black to give it its famous black finish.
Finally, if Mathias was choosing a polymer to use for records and money was no object, he’d go with polyimides. These materials have better thermal stability than vinyl, which has been known to warp when left in cars on sunny days. Polyimides can also reproduce grooves better and offer a more frictionless surface, Mathias adds.
(Editors Note: This is a fun article to read for audiophiles. I regret not having space for more than is presented here. Click through if you have time.)
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Sulfate Aerosols And The Summer That Wasn’t
For much of humanity, 1816 was the year that summer never came. In the US, where there were blizzards in June and frosts in August, people called it ‘Eighteen-hundred-and-froze-to-death’. Across Asia and Europe, crop failures caused mass starvation and political turmoil. And while apocalyptic thunderstorms raged over the Alps a party of literary exiles diverted themselves with Gothic horror stories, one of which was to have an enduring impact on the public image of science.
All these events were triggered by the explosion of Mount Tambora, a volcano on the island of Sumbawa (now part of Indonesia). On 5 April 1815, it blasted around 100km3 of solid matter into the sky, covering Sumbawa and nearby islands with a blanket of dust and ash up to a metre thick. The explosion and its immediate after-effects caused about 70,000 fatalities. But millions more died in the years that followed, because Tambora’s sulfur dioxide emissions created atmospheric aerosol particles which disrupted global weather patterns, bringing famine – and Frankenstein (see box) – to the world.
Today, disturbances in the atmosphere’s chemical composition remain a threat to humanity and a source of controversy. Anxious citizens struggle to comprehend confusing statistics and conflicting opinions. Powerful interest groups hire lobbyists to challenge research results that might inconvenience them. Climate scientists are accused of spreading panic to gain bigger research grants, while political opportunists encourage hostility towards science in general. The situation seems alarmingly close to those images of angry peasants outraged at a mad doctor’s unholy experiments, which Mary Shelley’s Gothic novel (and its cinematic reincarnations) have made familiar to millions.
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Some scientists have claimed that releasing artificially generated sulfate aerosols in the upper atmosphere could put a brake on runaway global warming. But others warn that the consequences of such a vast geo-engineering exercise are unpredictable, and could be disastrous. The wrong aerosol cocktail, or the wrong delivery method, might destroy the Earth’s protective ozone layer, or start a new ice age.
Feasibility studies for projects of this kind depend heavily on computer modelling, the parameters for which remain conjectural. Cautious small-scale experiments have so far failed to convince those who doubt the wisdom of pursing them further. While Frankenstein’s shadow still hovers over the debate, the story of Tambora’s eruption and the summerless year that followed it may offer us important lessons.
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Ecology
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Judge Rules: No Right To Know Hazardous Pesticide Ingredients
A federal judge in California has ruled that the US Environmental Protection Agency (EPA) has no duty under federal pesticide law to complete rulemaking on the disclosure of hazardous ingredients in pesticide products.
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The claimed 'proprietary interests' of chemical manufacturers are also "bogus", they maintain, "given the burgeoning market of pesticide products exempt from registration under the FIFRA 25(b) provision, which are required to disclose all ingredients."
An inert ingredient is defined as any ingredient that is 'not active', or specifically targeted to kill a pest. According to a 2000 report produced by the New York State Attorney General, The Secret Ingredients in Pesticides: Reducing the Risk, 72% of pesticide products available to consumers contain over 95% inert ingredients and fewer than 10% of pesticide products list any inert ingredients on their labels.
The report also found that more than 200 chemicals used as inert ingredients are hazardous pollutants in federal environmental statutes governing air and water quality, and, from 1995 list of inert ingredients, 394 chemicals were listed as active ingredients in other pesticide products. For example, naphthalene is an inert ingredient in some products and listed as an active ingredient in others.
Some 'inert' ingredients are even more toxic than the active ingredients. One of the most hazardous ingredients in the commonly used herbicide Roundup, POEA, is a surfactant, which is classified as an inert and therefore not listed on the label. Researchers have found that POEA can kill human cells, particularly embryonic, placental and umbilical cord cells.
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What Would A Global Warming Increase Of 1.5 Degrees Be Like?
How ambitious is the world? The Paris climate conference last December astounded many by pledging not just to keep warming “well below two degrees Celsius,” but also to "pursue efforts" to limit warming to 1.5 degrees C. That raised a hugely important question: What's the difference between a two-degree world and a 1.5-degree world?
Given we are already at one degree above pre-industrial levels, halting at 1.5 would look to be at least twice as hard as the two-degree option. So would it be worth it? And is it even remotely achievable?
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To remedy [..."a paucity of scientific analysis”], the paper’s researchers, led by Daniel Mitchell and others at Oxford University, called for a dedicated program of research to help inform what they described as "arguably one of the most momentous [decisions] to be made in the coming decade." And they are on the case, with their own dedicated website and a major conference planned at Oxford in the fall.
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A few studies have tried to drill down to what the difference means for day-to-day lives. And the consequences for many will be stark. At two degrees, parts of southwest Asia, including well-populated regions of the Persian Gulf and Yemen, may become literally uninhabitable without permanent air conditioning.
Some researchers predict a massive decline in the viability of food crops critical for human survival. The extra half-degree could cut corn yields in parts of Africa by half, says Bruce Campbell of the International Center for Tropical Agriculture. Schleussner found that even in the prairies of the U.S., the risk of poor corn yields would double.
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Physics
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Innovative Approach Makes For A Smoother Ride
Moving through water can be a drag, but the use of supercavitation bubbles can reduce that drag and increase the speed of underwater vehicles. Sometimes these bubbles produce a bumpy ride, but now a team of engineers from Penn State's Applied Research Laboratory have an approach that smooths out the ride and stabilizes the bubble.
In supercavitation, a bubble of gas encompasses an underwater vehicle reducing friction drag and allowing high rates of speed through the water.
"Basically supercavitation is used to significantly reduce drag and increase the speed of bodies in water," said Grant M. Skidmore, recent Penn State Ph.D. recipient in aerospace engineering. "However, sometimes these bodies can get locked into a pulsating mode, causing a problem with stability and noise."
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"Eventually we ramped up the gas really high and then way down to get pulsation," said Jules W. Lindau, senior research associate at ARL and associate professor of aerospace engineering. "It was a challenge because the walls of the tunnel are really close. Others couldn't get pulsation in a closed tunnel. That's what we did."
Once they could predictably create the phenomena in the water tunnel, they then had to apply their numerical solution to the experimental model. They found that once they had supercavitation with pulsation, they could alternate increasing the air flow and decreasing the air flow in a sinusoidal manner and, in many cases, the pulsation would stop. The amount and rate of air flow variation did not correlate to just one pulsation frequency, but could calm a range of pulsation states.
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New Surface Makes Oil Contamination Remove Itself
Researchers of Aalto University have developed surfaces where oil transports itself to desired directions. Researchers' oleophobic surfaces are microtextured with radial arrays of undercut stripes. When oil drops fall on surfaces, drops move away from the landing point to the direction set by asymmetric geometrical patterning of the surface. The surfaces open up new avenues for power-free liquid transportation and oil contamination self-removal applications in analytical and fluidic devices.
"We developed surfaces that are able to move liquid oil droplets by surface tension forces. Droplets from anywhere within the pattern will spontaneously move to the center of the pattern," tells Postdoctoral Researcher Ville Jokinen.
"Although surface engineering facilitates effective liquid manipulation and enables water droplet self-transportation on synthetic surfaces, self-transportation of oil droplets posed a major challenge because of their low surface tension," explains Postdoctoral Researcher Xuelin Tian.
New surfaces are also able to move low surface tension liquids other than oil. They work for water, wine and even pure ethanol.
Directional liquid transportation of water is also found in nature, for instance, in cactus needles and the shells of desert beetles. Researchers see a range of industrial applications.