Astronomy
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Asteroid Strikes On Mars Spun Out Supersonic Tornadoes That Scoured The Surface
The study of another planet’s surface features can provide a window into its deep past. Take Mars for example, a planet whose surface is a mishmash of features that speak volumes. In addition to ancient volcanoes and alluvial fans that are indications of past geological activity and liquid water once flowing on the surface, there are also the many impact craters that dot its surface.
In some cases, these impact craters have strange bright streaks emanating from them, ones which reach much farther than basic ejecta patterns would allow. According to a new research study by a team from Brown University, these features are the result of large impacts that generated massive plumes. These would have interacted with Mars’ atmosphere, they argue, causing supersonic winds that scoured the surface.
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“Where these vortices encounter the surface, they sweep away the small particles that sit loose on the surface, exposing the bigger blocky material underneath, and that’s what gives us these streaks. We know these formed at the same time as these large craters, and we can date the age of the craters. So now we have a template for looking at erosion.”
In addition, these streaks could reveal additional information about the state of Mars during the time of impacts. For example, Schultz and Quintana noted that the streaks appear to form around craters that are about 20 km (12.4 mi) in diameter, but not always. Their experiments also revealed that the presence of volatile compounds (such as surface or subsurface water ice) would affect the amount of vapor generated by an impact.
In other words, the presence of streaks around some craters and not others could indicate where and when there was water ice on the Martian surface in the past. It has been known for some time that the disappearance of Mars’ atmosphere over the course of several hundred million years also resulted in the loss of its surface water. By being able to put dates to impact events, we might be able to learn more about Mars’ fateful transformation.
Watery Skies Of “Warm Neptune” Hint At Planet’s Formation
Making Hot Jupiters and Warm Neptunes
Astronomers long thought that giant planets could only form beyond a system's frost lines, the lines beyond which molecules such as methane, water, and carbon dioxide freeze. With gases frozen into icy shards, there was far more material available for building planets. Closer to the star, those ices would sublimate into gas, making them unavailable for accretion.
Two scenarios get around that problem. The first is migration: gas giants could form far out beyond the frost line, then interact with the disk, a passing star, or another planet to move inward. The second is in situ formation: the idea that somehow, enough material was available close to the star to form hot giants where they now orbit.
Hats Off to HAT-P-26b
HAT-P-26b, a Neptune-mass planet 425 light-years away, passes in front of its star every 4 Earth days. So, every 4 days, it presents a good target for transmission spectroscopy: the method of capturing the sliver of starlight that passes through the planet's atmosphere. Hannah Wakeford (NASA Goddard) and colleagues used the Hubble Space Telescope to take that spectrum during four of the planet's transits. They also used archival Spitzer observations taken during two additional transits. Altogether, they reconstructed a spectrum spanning wavelengths between 0.5 and 5 microns — an ideal range when it comes to looking for water.
And they found what they were looking for: the spectrum shows some light cloud cover and a clear signature of water in the planet's gaseous envelope. Water serves as a representative of all the elements in the atmosphere heavier than hydrogen and helium. From the presence of water, it turns out that HAT-P-26b has 4.8 times as many heavy elements as the Sun, a measurement surprisingly close to Jupiter's (5 times greater than the Sun), and not so close to the measurement for Neptune (about 100 times greater than the Sun). So maybe we'd be better off calling the planet a warm-but-small Jupiter.
It's worth noting, that collecting a transmission spectrum isn't a precise science yet, and there's still a large range of uncertainty in this measurement: the true abundance of heavy elements in the planet's atmosphere could range from 0.8 to 26 times the Sun's value. Still, even with that large uncertainty, the planet bucks the trend we see in our own solar system: massive planets typically have fewer heavy elements, while less massive planets have more. Given that it's Neptune-mass, HAT-P-26b ought to have a lot more heavy elements than it does.
So, just like the much more massive Jupiter, HAT-P-26b appears to be made of mostly hydrogen and helium. And since that primordial mixture has apparently remained relatively undisturbed by heavier elements that might come in during the early phases of planet formation, this planet must have come together relatively late during the system's formation. A late formation wouldn't give it much time to migrate inward, Wakeford and colleagues argue, so the planet probably formed in situ instead, gathering its bulk from the inner reaches of this stellar system.
Biology
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Six-Legged Livestock For Sustainable Food Production
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Cricket farming can be a sustainable way to produce animal source foods
The study demonstrated that cricket farming can be a sustainable means of producing animal source foods. The study compared cricket production in Thailand to broiler chicken production. Fifteen different environmental impacts were investigated including global warming potential, resource depletion and eutrophication.
In most cases, cricket production had a lower impact than broiler chicken production. The major reason for the lower impacts is the fact that the feed conversion into animal protein is more efficient, as the production of the feed is a major hotspot in both systems.
"This research is very timely, as there are many different stakeholders interested in farmed insects. Many people have seen insects as a means of lowering the environmental burden of animal production. Insects, in many cases, can be comparable to meat and fish in terms of nutritional value. The fact that we have shown here that they can be produced more environmentally sustainably than meat means that they represent a massive potential for lowering the impact of the food production" explains lead author, PhD student Afton Halloran of the University of Copenhagen's Department of Nutrition, Exercise and Sports.
Possibility to become even more environmentally sustainable
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"While crickets consume plant matter in the wild, farmers started to use commercial chicken feeds because they saw that the crickets grew faster. Unfortunately, the production of feed ingredients like maize and soy can have detrimental effects on the environment. Luckily our colleagues at the Department of Entomology, Khon Kaen University are looking into other feed sources farmed crickets, such as different kinds of plants and waste products" concludes PhD student Afton Halloran.
In Thailand, cricket farming has been occurring for nearly 20 years with 20,000 farms scattered throughout the northeastern and northern parts of the country. Around the world, there are over 2,000 insect species that are regularly eaten. Most of these species are harvested from the wild, but around nine insect species are currently farmed for food and feed.
Rosemary Aroma Can Aid Children's Working Memory
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A total of 40 children aged 10 to 11 took part in a class based test on different mental tasks. Children were randomly assigned to a room that had either rosemary oil diffused in it for ten minutes or a room with no scent.
The children were tested individually, seated at the table opposite the researcher. After introducing herself to the child the researcher said: "You are here to play some memory games. Please don't be nervous but try the best you can to remember what I ask you to."
Analysis revealed that the children in the aroma room received significantly higher scores than the non-scented room. The test to recall words demonstrated the greatest different in scores.
Dr Moss said: "Why and how rosemary has this effect is still up for debate. It could be that aromas affect electrical activity in the brain or that pharmacologically active compounds can be absorbed when adults are exposed.
"We do know that poor working memory is related to poor academic performance and these findings offers a possible cost effective and simple intervention to improve academic performance in children. The time is ripe for large-scale trials of aroma application in education settings."
Chemistry
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Ink Chemistry
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The earliest black writing inks, developed before 2500BC, were suspensions of carbon, usually lampblack, in water stabilised with a natural gum or materials like egg albumen. Modern ink formulations are rather more complex. In addition to the pigment, they contain many other ingredients in varying levels. Collectively known as ’vehicle’, these additional ingredients include pH modifiers, humectants to retard premature drying, polymeric resins to impart binding and allied properties, defoamer/antifoaming agents to regulate foam efficiency, wetting agents such as surfactants to control surface properties, biocides to inhibit the fungal and bacterial growth that lead to fouling, and thickeners or rheology modifiers to control ink application.
Over 90 per cent of inks are printing inks, in which colour is imparted by pigments rather than the dyes used in writing inks. Pigments are insoluble, whereas dyes are soluble, though sometimes these terms are used interchangeably in commercial literature. Ink pigments are both inorganic and organic. Most red writing inks are a dilute solution of the red dye eosin. Blue colour can be obtained with substituted triphenylmethane dyes. Many permanent writing inks contain iron sulfate and gallic and tannic acids as well as dyes. Ballpoint ink is usually a paste containing 40 to 50 per cent dye.
Most white inks contain titanium dioxide as the pigment, as rutile and anatase in tetragonal crystalline form. However, growing concerns over the known toxicity of heavy metals have led to the replacement of many inorganic pigments such as chrome yellow, molybdenum orange and cadmium red with organic pigments, which offer better light fastness and reduced toxicity. Furthermore, carbon black now replaces spinel black, rutile black and iron black in nearly all black inks. In fact the ink industry is the second largest consumer of carbon black.
Other inorganic materials such as clays serve as fillers or extenders, which primarily reduces the cost of pigments, though some also improve ink properties. Metallic pigments like aluminium powder (aluminium bronze) and copper-zinc alloy powder (gold bronze) are used in novel silver and gold inks. Miscellaneous inorganic pigments provide luminescent and pearlescent effects.
Changes in ink chemistry over the years closely reflect developments in the instruments for ink coating: the pen and the printing machine. The ballpoint pen, the felt-tip marker, and the fibre-tip pen have led to inks containing solutions of dyes in water or organic solvents such as propylene glycol, propyl alcohol, toluene or glyco-ethers. Other ingredients like resins, preservatives and wetting agents are also added.
Ecology
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Next-Gen Solar Cells Could Be Improved By Atomic-Scale Redesign
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Solar cells harness energy from the Sun and provide an alternative to non-renewable energy sources like fossil fuels. However, they face challenges from costly manufacturing processes and poor efficiency - the amount of sunlight converted to useable energy.
Light-absorbing materials called organic lead halide perovskites are used in a new type of solar cells that have shown great promise, as they are more flexible and cheaper to manufacture than traditional solar cells constructed of silicon.
However, perovskite cells degrade rapidly in natural conditions, greatly decreasing their performance in a matter of days. This is one reason they are not currently widely used.
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Better solutions
Currently, the only way of protecting perovskite cells from degradation by air and light is to encase them in glass. However, perovskite solar cells are made from flexible material designed to be used in a range of settings, so the glass encasement severely limits their function.
Dr Haque said: “Glass encasement restricts movement and adds weight and cost to the cells. Improving the perovskite cell material itself is the best solution.”
Study Analyses Foods For Radioactive Substances
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"Even though radiation emitting radioactive elements like uranium are only contained in small quantities in food, their chemical properties and radioactivity could pose a risk if they are ingested over a longer period in higher concentrations. The actual risk is now being assessed within the scope of the cooperation with the BfS," explains BfR President Professor Dr. Dr. Andreas Hensel. "In this way, the BfS and BfR will jointly obtain more data for risk assessment," Hensel adds.
"Humans cannot perceive or feel radiation with their senses," says Wolfram König, President of the Federal Office for Radiation Protection, "so people must have valid and reliable data, which we provide. This joint study should help us gain a better understanding of possible or negligible risks and enable us to compare and classify them".
In the BfR MEAL Study, the BfR is examining foods for the first time in Germany for various substances such as nutrients, heavy metals and food additives in order to determine the mean concentrations of these substances in the average human diet. Of the foods already prepared in the kitchen of the BfR MEAL study in typical home-cooked fashion, the BfS is given selected samples to examine for various natural radionuclides such as uranium, radium-226, radium-228 and lead-210. The background of this is that natural radionuclides can occur in different concentrations and combinations in rock and minerals everywhere in the environment, which means that they can also be contained in foods.
The selection of the foods by the BfS is based on the National Nutrition Study II and covers above all cereal products, vegetables, potatoes, dairy produce, meat and fish. The BfS analyses various radioactive elements in the food samples and will make dosage estimations for the general public on the basis of the test results.
The BfR MEAL Study was commissioned by the Federal Ministry of Food and Agriculture (BMEL). It is set to run for seven years and will essentially take into account the entire range of food consumed in Germany. The goal is to gain information for the first time in Germany about the concentrations of various substances contained in the foods eaten by consumers.
Physics
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Physicists Find A Way To Control Charged Molecules -- With Quantum Logic
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The new technique achieves an elusive goal, controlling molecules as effectively as laser cooling and other techniques can control atoms. Quantum control of atoms has revolutionized atomic physics, leading to applications such as atomic clocks. But laser cooling and control of molecules is extremely challenging because they are much more complex than atoms.
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Compared to atoms, molecules are more difficult to control because they have more complex structures involving many electronic energy levels, vibrations and rotations. Molecules can consist of many different numbers and combinations of atoms and be as large as DNA strands more than a meter long.
The NIST method finds the quantum state (electronic, vibrational, and rotational) of the molecular ion by transferring the information to a second ion, in this case an atomic ion, which can be laser cooled and controlled with previously known techniques. Borrowing ideas from NIST's quantum logic clock, the researchers attempt to manipulate the molecular ion and, if successful, set off a synchronized motion in the pair of ions. The manipulation is chosen such that it can only trigger the motion if the molecule is in a certain state. The "yes" or "no" answer is signaled by the atomic ion. The technique is very gentle, indicating the molecule's quantum states without destroying them.
"The molecule only jiggles if it is in the right state. The atom feels that jiggle and can transfer the jiggle into a light signal we can pick up," senior author Dietrich Leibfried said. "This is like Braille, which allows people to feel what is written instead of seeing it. We feel the state of the molecule instead of seeing it and the atomic ion is our microscopic finger that allows us to do that."
"Moreover, the method should be applicable to a large group of molecules without changing the setup. This is part of NIST's basic mission, to develop precision measurement tools that maybe other people can use in their work," Leibfried added.