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Why Did My Post Get Removed? or How To Write A Good Science Post

This is a huge and fascinating community and the strong guidelines are what we think make it that way.  We heavily moderate this community and you might see your post disappear.  Why?  We want the best science posts possible. 

The number one reason a post will be removed is, it might be what can be called Link Litter or a One Liner.  These are posts that say just one sentence or even just one word describing a link.  "Interesting"  or   "I just found this and wanted to post it"  are not a good lead-in to a post and will usually get the post removed. This is also not a place for memes, there are many other communities devoted to just memes and jokes.  Please no self promotion.

Composition  - Please,  "No links without explanation. Accompany any link with an explanation of why you think it's share worthy. Write a paragraph or two (not just a sentence) that summarizes the key scientific content and why you were intrigued."

Sources - Please check your sources; if you can, find the original research paper and post a link so people who are interested can see what it was that you found so stimulating.  You have the largest library in the world, right at your fingertips.

Videos - Remember that many people read from a mobile device and might not have the bandwidth to view that video you really like.  So give a good description that will entice those people to come back and have a look later.  Also please give full credit to all videos, someone worked hard to make that science video, and they deserve the acknowledgement. 

Asking Questions see https://plus.google.com/117751903650439005786/posts/88zsXNWUWNu

Posting here is not hard, it just takes a little work on your part to make your post one that people will read and comment on.  And, check those comments; please, don't post and run.  

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This community, it's moderators, owners and other members make no representation towards the ability to maintain, preserve or protect the copyright as we are users here ourselves. Please contact +Google   for terms of use and permissions thereof.

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To understand the role of forests in both giving off and capturing carbon dioxide, researchers incorporated into an Earth system model the complex role of the ecosystem in intensifying or weakening carbon dioxide concentration in the atmosphere. It involves a process called dynamic vegetation—where plants can shift their habitats in response to environmental changes. Learn more about this research at https://goo.gl/XXBW5H.

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"Carbon cycle feedback." When it comes to understanding the forests' role in both giving off and capturing carbon dioxide, those are three words that contain a lot of science. In a new study, researchers led by Pacific Northwest National Laboratory incorporated into an Earth system model the complex role of the ecosystem in amping or damping the concentration of carbon dioxide (CO2) in the atmosphere.

It's a process called dynamic vegetation—where plants can shift their habitats in response to environmental changes such as a hotter weather system or limited nutrients. Using a land-system model with dynamic vegetation enabled or disabled, the research team found that nitrogen and its interaction with plants has a strong influence on how plants respond to environmental changes. This influence can result in amplification or reduction of carbon dioxide, which is responsible for the environmental changes in the first place. The research showed how effective modeling of dynamic vegetation and the nitrogen cycle can increase understanding of carbon cycle and future climate changes.

Among the Earth system models that contributed to the Intergovernmental Panel on Climate Change (IPCC) fifth assessment report in 2013, only a handful included dynamic vegetation, and even fewer incorporated the nitrogen cycle. Evidence is growing that these two processes will play a key role in the future carbon cycle.

Scientists at PNNL and their collaborators studied one of the few global land models, the Community Land Model version 4, that is able to simulate vegetation cover change responding to both the evolving climate and nitrogen cycle. By running a series of simulations for different climate and CO2 change scenarios, they were able to calculate the sensitivity of terrestrial carbon to climate warming and CO2 increase. Land carbon sensitivity is an important factor that constitutes the feedback to CO2 increase. The effect of vegetation change on this factor has rarely been studied. The team repeated the same set of experiments without a dynamic vegetation model.

Their analysis showed a significant difference in the potential strength of the carbon cycle feedback with and without the dynamic vegetation cover that responds to the climate state. The team also found a link between the emerging characteristics of plant nitrogen demand from inadequate representation of plant competition in the dynamic vegetation model over the tropics and subtropics. The analysis also found that errors in simulating vegetation cover can propagate to broader scales through interaction with the nitrogen cycle. The research illustrated a specific example of such error propagation to guide model development efforts.

Why is this important? The terrestrial ecosystem plays a large role in the Earth's carbon cycle by inhaling and exhaling CO2 from the atmosphere. A higher level of CO2 helps plants more efficiently use the sun's energy for photosynthesis, which causes them to remove (inhale) more CO2 from the atmosphere. On the other hand, a higher CO2 level in the atmosphere leads to higher temperatures, which can impose heat stress on plants and hasten the organic matter in surface plant litter and soil to decompose. Both the increased stress and the faster decomposition of organic material add more CO2 into the atmosphere than is removed by the increased photosynthesis. This net increase of CO2 exhalation by plants as atmospheric CO2 increases is a positive carbon cycle feedback that amplifies CO2 in the atmosphere.

But here's where nitrogen throws a wrench into the carbon cycle gears. Faster decomposition of organic carbon makes more nitrogen available to plants, helping them take in more CO2 as they grow, reducing the atmospheric levels. This is a negative carbon cycle feedback. However, the strength of this negative carbon cycle feedback is dependent on whether the vegetation type is allowed to shift with environmental changes because some plants require more nitrogen than others. This study demonstrated how the nitrogen cycle and dynamic vegetation and their interaction determine how plants across the globe can amplify or dampen the increase of atmospheric CO2 and associated climate warming.

What's Next? With the relevant vegetation processes improved in the next generation Earth system models, representation of the carbon cycle feedback can be better characterized. Future studies will perform simulations with the global land model coupled to atmosphere, ocean, and other Earth system component models to quantify carbon-climate interactions, with a particular focus on the tropical forest setting.

Acknowledgments: The +U.S. Department of Energy's (DOE's) Office of Science, Biological and Environmental Research supported this project as part of the Regional and Global Climate Modeling Program. This work was also supported by the +National Science Foundation and the National Natural Science Foundation of China.

Reference: Sakaguchi K, X Zeng, LR Leung, and P Shao. 2016. "Influence of Dynamic Vegetation on Carbon-Nitrogen Cycle Feedback in the Community Land Model (CLM4)." Environmental Research Letters 11(12):124029. DOI: 10.1088/1748-9326/aa51d9 
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Once upon a time, not so very long ago, scientists could only postulate at the existence of planets orbiting other suns. Today, the race is on to find the first with signs of life, and it's hot.
Once upon a time, not so very long ago, scientists could only postulate at the existence of planets orbiting other suns. Today, the race is on to find the first with signs of life, and it's hot.


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Silky chocolate, a better medical drug or solar panels all require the same thing: just the right crystals making up the material. Now, scientists trying to understand the paths crystals take as they form have been able to influence that path by modifying the starting ingredient. The findings of this research could eventually help them better control the design of a variety of products for energy or medical technologies. Read more at https://goo.gl/ZnIG2Z.

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"The findings address an ongoing debate about crystallization pathways," said materials scientist Jim De Yoreo at the Department of Energy's Pacific Northwest National Laboratory and the +UW (University of Washington). "They imply you can control the various stages of materials assembly by carefully choosing the structure of your starting molecules."
From floppy to stiff

One of the simplest crystals, diamonds are composed of one atom — carbon. But in the living world, crystals, like the ones formed by cocoa butter in chocolate or ill-formed ones that cause sickle cell anemia, are made from molecules that are long and floppy and contain a lengthy well-defined sequence of many atoms. They can crystallize in a variety of ways, but only one way is the best. In pharmaceuticals, the difference can mean a drug that works versus one that doesn't.

Chemists don't yet have enough control over crystallization to ensure the best form, partly because chemists aren't sure how the earliest steps in crystallization happen. A particular debate has focused on whether complex molecules can assemble directly, with one molecule attaching to another, like adding one playing card at a time to a deck. They call this a one-step process, the mathematical rules for which scientists have long understood.

The other side of the debate argues that crystals require two steps to form. Experiments suggest that the beginning molecules first form a disordered clump and then, from within that group, start rearranging into a crystal, as if the cards have to be mixed into a pile first before they could form a deck. De Yoreo and his colleagues wanted to determine if crystallization always required the disordered step, and if not, why not.
Clump, snap and ...

To do so, the scientists formed crystals from a somewhat simplified version of the sequence-defined molecules found in nature, a version they call a peptoid. The peptoid was not complicated — just a string of two repeating chemical subunits (think "ABABAB") — yet complex because it was a dozen subunits long. Based on its symmetrical chemical nature, the team expected multiple molecules to come together into a larger structure, as if they were Lego blocks snapping together.

In a second series of experiments, they wanted to test how a slightly more complicated molecule assembled. So, the team added a molecule onto the initial ABABAB... sequence that stuck out like a tail. The tails attracted each other, and the team expected their association would cause the new molecules to clump. But they weren't sure what would happen afterwards.

The researchers put the peptoid molecules into solutions to let them crystallize. Then the team used a variety of analytical techniques to see what shapes the peptoids made and how fast. It turns out the two peptoids formed crystals in very different fashions.
A tail of two steps

As the scientists mostly expected, the simpler peptoid formed initial crystals a few nanometers in size that grew longer and taller as more of the peptoid molecules snapped into place. The simple peptoid followed all the rules of a one-step crystallization process.

But thrusting the tail into the mix disrupted the calm, causing a complex set of events to take place before the crystals appeared. Overall, the team showed that this more complicated peptoid first clumped together into small clusters unseen with the simpler molecules.

Some of these clusters settled onto the available surface, where they sat unchanging before suddenly converting into crystals and eventually growing into the same crystals seen with the simple peptoid. This behavior was something new and required a different mathematical model to describe it, according to the researchers. Understanding the new rules will allow researchers to determine the best way to crystallize molecules.

"We were not expecting that such a minor change would make the peptoids behave this way," said De Yoreo. "The results are making us think about the system in a new way, which we believe will lead to more predictive control over the design and assembly of biomimetic materials."

Funding: This work was supported by the +U.S. Department of Energy Office of Science and PNNL's Laboratory Directed Research and Development program.

Reference: Xiang Ma, Shuai Zhang, Fang Jiao, Christina Newcomb, Yuliang Zhang, Arushi Prakash, Zhihao Liao, Marcel Baer, Christopher Mundy, Jim Pfaendtner, Aleksandr Noy, Chun-Long Chen and Jim De Yoreo, Tuning crystallization pathways through sequence-engineering of biomimetic polymers. Nature Materials, April 17, 2017, DOI: 10.1038/nmat4891. 
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Offshore wind has huge potential to help meet our energy needs. Developing just 1 percent of its potential could power nearly 6.5 million homes. With an array of advanced research equipment, PNNL’s offshore research buoys recently returned from a 19-month deployment off the coast of Virginia. Researchers are analyzing collected data, which will help validate wind predictions and improve our understanding of air-sea interactions. Learn more about this research and DOE's buoy loan program at https://goo.gl/0AMgxS; watch our video at http://bit.ly/2o76yA4.

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PNNL is working to accelerate prediction of the power-producing potential of offshore wind at an east coast site using two research buoys. The +U.S. Department of Energy's Wind Energy Technologies Office commissioned PNNL to procure and deploy two bright-yellow buoys—each worth $1.3 million.

The buoys are decked out with advanced scientific instruments designed to measure wind speed at multiple heights, air and sea surface temperature, barometric pressure, relative humidity, wave height and period, and water conductivity. Doppler sensors measure subsurface ocean currents.

After a 19-month deployment off the coast of Virginia Beach(Offsite link), one of the buoys has returned to shore. In collaboration with the State of Virginia, PNNL examined the quality of the data and discovered that stronger winds produced more accurate data—likely as a result of the additional sea spray high winds generate.

The increase in spray provides more particles for the LiDAR (Lighting Detection and Ranging) pulse to bounce off of, improving signal strength and return rates. Similarly, researchers found data recovery rates are higher during the warm season and the daytime.

PNNL also found that above 90 meters (295 feet), signal noise affected the integrity of the data. Further analysis revealed that by removing samples with low signal strengths and averaging data across 10-minute intervals, accurate results could be achieved.

Additional analysis performed by researchers at +Texas Tech University found offshore winds in the U.S. differ from European offshore environments. In the U.S., winds are more sheared, changing velocity and direction more frequently at lower levels in the atmosphere (low-level jets). While low-level jets do not significantly impact the power performance of an offshore wind turbine, their occurrence might lead to inaccurate assessment of the resource as well as increased fatigue loading on wind turbine components.

The data and buoys will help scientists and developers better understand air-sea interactions and their impact on how much wind energy a turbine could capture at particular offshore sites. The data will also help validate the wind predictions derived from computer models, which have thus far relied on extremely limited real-world observational data in U.S. coastal waters. 
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New, early-stage research shows that adding a small amount of a particular chemical to electrolyte helps make rechargeable lithium-metal batteries stable, charge quickly, have high voltage, and go longer in between charges. “A good lithium-metal battery will have the same lifespan as the lithium-ion batteries that power today's electric cars and consumer electric devices, but also store more energy so we can drive longer in between charges," said PNNL chemist Wu Xu. Read more at https://goo.gl/FKtuhY.

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Most of the rechargeable batteries used today are lithium-ion batteries, which have two electrodes: one that's positively charged and contains lithium, and another negative one that's typically made of graphite. Electricity is generated when electrons flow through a wire that connects the two.

To control the electrons, positively charged lithium atoms shuttle from one electrode to the other through another path, the electrolyte solution in which the electrodes sit. But graphite can't store much energy, limiting the amount of energy a lithium-ion battery can provide smart phones and electric vehicles.

When lithium-based rechargeable batteries were first developed in the 1970s, researchers used lithium metal for the negative electrode, called an anode. Lithium was chosen because it has ten times more energy storage capacity than graphite. Problem was, the lithium-carrying electrolyte reacted with the lithium anode. This caused microscopic lithium nanoparticles and branches called dendrites to grow on the anode surface, and led the early batteries to fail.

Many have tweaked rechargeable batteries over the years in an attempt to resolve the dendrite problem. Researchers switched to other materials such as graphite for the anode. Scientists have also coated anodes with protective layers, while others have created electrolyte additives. Some solutions eliminated dendrites but also resulted in impractical batteries with little power. Other methods only slowed, but didn't stop, dendrite growth.
Next-generation storage

Thinking today's rechargeable lithium-ion batteries with graphite anodes could be near their peak energy capacity, PNNL is taking another look at the older design with lithium metal as an anode. Xu and colleagues were part of earlier PNNL research seeking a better-performing electrolyte. The electrolytes they tried produced either a battery that didn't have problematic dendrites and was super-efficient but charged very slowly and couldn't work in higher-voltage batteries, or a faster-charging battery that was unstable and had low voltages.

Next, they tried adding small amounts of a salt that's already used in lithium-ion batteries, lithium hexafluorophosphate, to their fast-charging electrolyte. They paired the newly juiced-up electrolyte with a lithium anode and a lithium nickel manganese cobalt oxide cathode. It turned out to be a winning combination, resulting in a fast, efficient, high-voltage battery.

The additive enabled a 4.3-volt battery that retained more than 97 percent of its initial charge after 500 repeated charges and discharges, while carrying 1.75 milliAmps of electrical current per square centimeter of area. It took the battery about one hour to fully charge.
Inexpensive protection

The battery performed well largely because the additive helps create a robust protective layer of carbonate polymers on the battery's lithium anode. This thin layer prevents lithium from being used up in unwanted side reactions, which can kill a battery.

And, because the additive is already an established component of lithium-ion batteries, it's readily available and relatively inexpensive. The small amounts needed — just 0. 6 percent of the electrolyte by weight — should also further lower the electrolyte's cost.

Xu and his team continue to evaluate several ways to make rechargeable lithium-metal batteries viable, including improving electrodes, separators and electrolytes. Specific next steps include making and testing larger quantities of their electrolyte, further improving the efficiency and capacity retention of a lithium-metal battery using their electrolyte, increasing material loading on the cathode and trying a thinner anode.

This research was supported by the +U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy. Researchers performed microscopy and spectroscopy characterizations of battery materials at the +Environmental Molecular Sciences Laboratory (EMSL) at PNNL. The battery electrodes were made at DOE's Cell Analysis, Modeling, and Prototyping Facility at +Argonne National Laboratory. 
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Scientists have learned more about how molds become cellular factories that can synthesize a range of diverse products, including precursors to alternative fuels. The findings — made at the Environmental Molecular Sciences Laboratory at PNNL — have implications for energy production, agriculture and human health. Read more at https://goo.gl/ZQwiz0.

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Molds produce a wide range of both valuable and toxic molecules, which have important implications for energy production, agriculture and human health. A recent study revealed that an organelle within fungal cells called the endoplasmic reticulum acts as a cellular factory for synthesizing diverse natural products called sesquiterpenes in fungal cells.

The Impact: While some sesquiterpenes are toxins that contaminate cultivated grains and pose a health risk to humans, others are potential precursors to alternative fuels. Understanding how molds make these molecules is essential for engineering fungal cells to produce valuable products instead of harmful toxins.

Summary: Filamentous fungi, commonly known as molds, produce a remarkable diversity of natural molecules with unique properties. Many of those properties (byproducts) have been used as pharmaceuticals and antibiotics, and some may be promising alternatives to fossil fuels. But other byproducts are toxins that can contaminate the world’s food supply. Despite the importance of these molecules in medicine and agriculture, it has not been clear which cellular compartments are involved in synthesizing natural products in fungal cells.

To address this question, researchers from the +University of Minnesota, +USDA ARS Cereal Disease Laboratory; the +Environmental Molecular Sciences Laboratory (EMSL) at PNNL, Pacific Northwest National Laboratory (PNNL); and +Oregon State University combined microscopy with proteomics to investigate how toxic molecules called sesquiterpenes are formed in the plant-infecting fungus Fusarium graminearum.

To do so, they used an Influx flow cytometer/cell sorter and an Orbitrap mass spectrometer at EMSL, a DOE Office of Science user facility. The results revealed that a cellular compartment called the endoplasmic reticulum (ER) serves as a cellular factory for producing specific sesquiterpene molecules.

The ER acts as a central staging area to gather raw materials for sesquiterpene synthesis as well as an assembly line coordinating multiple steps of the biosynthetic reaction pathway to streamline the efficiency of sesquiterpene synthesis. These findings could have important implications for energy production, agriculture and human health. Some scientists have proposed a sesquiterpene called bisabolene could be a precursor for a viable alternative to biodiesel fuels. On the other hand, fungi use the same molecular pathway to produce a compound known as vomitoxin, which contaminates grains such as wheat and barley and poses a health risk to humans.

By understanding how these molecules are synthesized in fungal cells, it may be possible to engineer this biochemical pathway to generate valuable products instead of undesirable toxins.

Funding: This work was supported by the +U.S. Department of Energy Office of Science (Office of Biological and Environmental Research), including support of the Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science User Facility and United States Department of Agriculture.

Publication: M.J. Boenisch, K.L. Broz, S.O. Purvine, W.B. Chrisler, C.D. Nicora, L.R. Connolly, M. Freitag, S.E. Baker and H.C. Kistler, “Structural reorganization of the fungal endoplasmic reticulum upon induction of mycotoxin biosynthesis.” Scientific Reports 7,44296 (2017). [DOI: 10.1038/srep44296]
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For decades, scientists studied the reactions between water and oxides without definitively resolving water's stability, or how much energy is needed to split water molecules. Now, a PNNL team has ended years of debate by precisely measuring stability of water and its fragments. This research has wide-ranging significance for researchers working to improve the catalysts involved in producing fuels, chemicals and other industrial products. Read more at https://goo.gl/PzOsl9.

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When a molecule of water comes in for a landing on the common catalyst titanium oxide, it sometimes breaks up and forms a pair of molecule fragments known as hydroxyls. But scientists had not been able to show how often the breakup happened. Now, researchers have determined that water is only slightly more likely to stay in one piece as it binds to the catalyst surface than it is to form the hydroxyl pairs.

The result — water's advantage is so small — might surprise some chemists. But understanding that small advantage has wide-ranging significance for a variety of potential applications in industries that use titanium dioxide. These industries include alternative fuel production, solar energy and food safety, and even self-cleaning windows. It will also help scientists better understand how acids behave and expand their knowledge of how molecules split.

"How water binds was the big question," said chemist Zdenek Dohnalek at PNNL. "Chemists had mixed information from a lot of different methods, and theorists also had ideas. Using a unique combination of instruments, we've finally solved it."

The team reported the work in the Proceedings of the National Academy of Sciences.

Even though many industries use titanium oxide to help speed up chemical reactions, scientists have not uncovered all of its secrets. A key mystery, researchers have long debated, is the way in which water interacts with titanium oxide. The interaction is important in its own right to split water, but it also influences the course of many reactions in general.

On titanium oxide's surface, molecules of water switch between being intact and splitting into hydroxyls. Even though there are many different ways of measuring the ratio of intact water to hydroxyls at any given time, scientists have not been able to nail it down for decades.

To explore the problem, PNNL researchers combined different tools in a new way. They sent beams of water at various speeds onto cold titanium oxide sitting under a very high resolution microscope known as a scanning tunneling microscope.

The microscope let them visualize the catalyst's titanium and oxygen atoms. The atoms appear as bright and dark rows, like a cornfield with tall rows of corn alternating with ditches, and individual molecules of water appear as bright spots that don't align with the rows.

In addition to viewing water molecules as they hit the surface, the team simulated details of the atoms interacting in exacting detail on a high performance computer. Combining experiments and simulations allowed the team to settle the long-standing debate.
Instant attraction

Shaped like a V, a water molecule has a fat oxygen atom in the middle bound to two smaller hydrogen atoms on either side. Titanium oxide helps break the bonds between the atoms to push a chemical reaction forward: the titanium atoms trap water molecules, while nearby oxygens, also part of the catalyst surface, draws away then captures one of the hydrogen atoms.

When this happens, two hydroxyls are formed, one from a surface oxygen combining with the hydrogen and the other leftover from the water molecule.

The scientists needed to know how often the hydroxyls formed. Do water molecules largely stay intact on the surface? Or do they immediately convert to hydroxyls? How likely water will stay intact on titanium oxide — and how easily the hydroxyls reform into water — sets the stage for other chemical reactions.

To find out, the chemists had to develop technologies to measure how often the hydroxyls arose on the surface. Using resources developed within the +Environmental Molecular Sciences Laboratory (EMSL) at PNNL, they shot a beam of water molecules at a titanium oxide surface at low energy — the beam shooting slowly, and at high energy — moving fast like out of a firehose.

They ended up with bright spots on the surface, and the higher the energy, the more spots. But the spots did not look bright enough to include both hydroxyls, as expected, so they performed additional experiments to determine what the spots were.
Spot on

The team shot water at the titanium dioxide surface and then froze the water in place. Then they slowly warmed everything up. Raising the temperature revealed the spots — which they thought were at least one hydroxyl — changing into water molecules. This meant that each spot had to actually be a pair of hydroxyls because the evidence showed that all the raw materials needed to make a water molecule were sitting there, and both hydroxyls were needed.

They performed various other experiments to determine the temperature at which a landing water molecule converts into hydroxyl pairs and vice versa. From that they learned that water is only slightly more stable than the hydroxyl pairs on the surface — 10 percent more, if we go by the amount of energy it takes to disrupt them.

Simulating the water landings on a high performance computer, also at EMSL, the researchers found out the only water molecules that stuck to the catalyst were ones that landed in a figurative ditch within a cornfield, where the water's oxygen faced a titanium atom down in the ditch.

If the water came in with just the right speed, the water reoriented and docked one of its hydrogens towards a nearby oxygen, forming the hydroxyl pairs seen in the experiments. If not, the water molecule just bounced off.

"We discovered that electrostatics — the same static that makes sparks when you rub your feet on the carpet — helped steer the water molecules onto the surface," said theoretical chemist and coauthor Roger Rousseau.

All of these details will help researchers understand catalysis better and improve our understanding of chemical reactions. In addition, the results reveal a value that scientists have long tried to nail down — how easy or hard it is for water to lose a hydrogen on titanium oxide.

Funding: This work was supported by the American Recovery and Reinvestment Act and the +U.S. Department of Energy Office of Science.

Reference: Zhi-Tao Wang, Yang-Gang Wang, Rentao Mu, Yeohoon Yoon, Arjun Dahal, Gregory K. Schenter, Vassiliki-Alexandra Glezakou, Roger Rousseau, Igor Lyubinetsky, and Zdenek Dohnálek. Probing Equilibrium of Molecular and Deprotonated Water on TiO2(110), Proc Natl Acad Sci U S A Early Edition February 6, 2017, DOI: 10.1073/pnas.1613756114.
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Identical Snowflakes? Scientist Ruins Winter For Everyone

California’s historic drought is finally over, thanks largely to a relentless parade of powerful storms that have brought the Sierra Nevada snowpack to the highest level in six years, not to mention guaranteed skiing into June. All that snow spurs an age-old question — is every snowflake really unique?

“It’s one of these questions that’s been around forever,” said Ken Libbrecht, a professor of physics at the California Institute of Technology in Pasadena. “I think we all learn it in elementary school, the old saying that no two snowflakes are alike.”

Libbrecht spends most of his time thinking about things like black holes and gravitational waves. But for years the North Dakota native has also delved into the mystery of how snowflakes grow into such a dizzying variety of shapes, all based on the same ingredient — water.

So is it possible to find two snowflakes that are exactly the same?

They can be made in a lab. But when it comes to nature, it’s possible, but you’re not likely to find two that match exactly, Libbrecht said.

“It goes back to how they’re made in the clouds,” he said.

Snow crystals form when humid air is cooled to the point that molecules of water vapor start sticking to each other.

Water molecules are each made out of one oxygen and two hydrogen atoms. Good ‘ol H2O!

The molecules fit together in the shape of a hexagonal ring with bonds forming between hydrogen of one molecule and the oxygen of another molecule.

As more molecules join the growing crystal, they fit into that repeating shape, which is why you tend to find snowflakes with six arms.

In a refrigerated chamber at his lab, Libbrecht built a device that mimics the conditions found in the clouds.

In the bottom of the chamber, Libbrecht keeps a container of hot water. As the water evaporates, it fills the chamber with water vapor. When the air is as humid as it can get, Libbrecht triggers a puff of condensed air that drops the temperature in the chamber suddenly.

That blast of cold air causes the water molecules to stick to each other, forming tiny ice crystals about the same diameter as a human hair.

In the clouds, crystals usually start forming around a tiny microscopic dust particle. But if the water vapor is cooled quickly enough the crystals can form spontaneously from water molecules alone.

“At this point they they’re just little tiny hexagons,” says Libbrecht. “We call them seed crystals.”

After a few moments of floating around the chamber, the tiny crystals grow big and heavy enough to fall. Libbrecht catches them on a small refrigerated slide.

He adjusts the humidity and temperature and, using a microscope, watches the crystals grow.

Read the rest of the article: https://ww2.kqed.org/science/2017/04/11/identical-snowflakes-scientist-ruins-winter-for-everyone-deep-look

Ken Libbrecht’s online guide to snowflakes, snow crystals and other ice phenomena: http://snowcrystals.com/


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Breaking: Atmosphere around super-Earth detected!

Gliese 1132 b is 1.6 Earth Masses, orbiting red dwarf GJ 1132 and is located only approximately 39 light years away!

"Astronomers have detected an atmosphere around the super-Earth GJ 1132b. This marks the first detection of an atmosphere around an Earth-like planet other than Earth itself, and thus a significant step on the path towards the detection of life on an exoplanet. The team, which includes researchers from the Max Planck Institute for Astronomy, used the 2.2 m ESO/MPG telescope in Chile to take images of the planet's host star GJ 1132, and measuring the slight decrease in brightness as the planet and its atmosphere absorbed some of the starlight while passing directly in front of their host star."

Read more at: https://phys.org/news/2017-04-atmosphere-super-earth.html

The Study: John Southworth et al. Detection of the Atmosphere of the 1.6Exoplanet GJ 1132 b, The Astronomical Journal (2017). https://arxiv.org/abs/1612.02425

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