New 'Diamond?' New Form of Superhard Carbon Is as Strong as a Diamond

Carbon is the fourth-most-abundant element in the universe and takes on a wide variety of forms, called allotropes, including diamond and graphite. Scientists at Carnegie's Geophysical Laboratory are part of a team that has discovered a new form of carbon, which is capable of withstanding extreme pressure stresses that were previously observed only in diamond.This breakthrough discovery will be published in Physical Review Letters.

The team was led by Stanford's Wendy L. Mao and her graduate student Yu Lin and includes Carnegie's Ho-kwang (Dave) Mao, Li Zhang, Paul Chow, Yuming Xiao, Maria Baldini, and Jinfu Shu. The experiment started with a form of carbon called glassy carbon, which was first synthesized in the 1950s, and was found to combine desirable properties of glasses and ceramics with those of graphite. The team created the new carbon allotrope by compressing glassy carbon to above 400,000 times normal atmospheric pressure.

This new carbon form was capable of withstanding 1.3 million times normal atmospheric pressure in one direction while confined under a pressure of 600,000 times atmospheric levels in other directions. No substance other than diamond has been observed to withstand this type of pressure stress, indicating that the new carbon allotrope must indeed be very strong.

However, unlike diamond and other crystalline forms of carbon, the structure of this new material is not organized in repeating atomic units. It is an amorphous material, meaning that its structure lacks the long-range order of crystals. This amorphous, superhard carbon allotrope would have a potential advantage over diamond if its hardness turns out to be isotropic -- that is, having hardness that is equally strong in all directions. In contrast, diamond's hardness is highly dependent upon the direction in which the crystal is oriented.

"These findings open up possibilities for potential applications, including super hard anvils for high-pressure research and could lead to new classes of ultradense and strong materials," said Russell Hemley, director of Carnegie's Geophysical Laboratory.

This research was funded, in part, by the Department of Energy's Office of Basic Energy Sciences Division of Materials Sciences and Engineering, EFree, HPCAT, where some of the experiments were performed, is funded by DOE-BES, DOE-NNSA, NSF, and the W.M. Keck Foundation. APS, where some of the experiments were performed, is supported by DOE-BES.

How the Brain Makes Memories:

Hi guys i found something interesting on net that How brain makes memories so I thought u'll also like so here is explanation.

The brain learns through changes in the strength of its synapses -- the connections between neurons -- in response to stimuli. Now, in a discovery that challenges conventional wisdom on the brain mechanisms of learning, UCLA neuro-physicists have found there is an optimal brain "rhythm," or frequency, for changing synaptic strength. And further, like stations on a radio dial, each synapse is tuned to a different optimal frequency for learning.The findings, which provide a grand-unified theory of the mechanisms that underlie learning in the brain, may lead to possible new therapies for treating learning disabilities.

The study appears in the current issue of the journal Frontiers in Computational Neuroscience.

"Many people have learning and memory disorders, and beyond that group, most of us are not Einstein or Mozart," said Mayank R. Mehta, the paper's senior author and an associate professor in UCLA's departments of neurology, neurobiology, physics and astronomy. "Our work suggests that some problems with learning and memory are caused by synapses not being tuned to the right frequency."

A change in the strength of a synapse in response to stimuli -- known as synaptic plasticity -- is induced through so-called "spike trains," series of neural signals that occur with varying frequency and timing. Previous experiments demonstrated that stimulating neurons at a very high frequency (e.g., 100 spikes per second) strengthened the connecting synapse, while low-frequency stimulation (e.g., one spike per second) reduced synaptic strength.

These earlier experiments used hundreds of consecutive spikes in the very high-frequency range to induce plasticity. Yet when the brain is activated during real-life behavioral tasks, neurons fire only about 10 consecutive spikes, not several hundred. And they do so at a much lower frequency -- typically in the 50 spikes-per-second range.

In other words, said Mehta, "spike frequency refers to how fast the spikes come. Ten spikes could be delivered at a frequency of 100 spikes a second or at a frequency of one spike per second."

Until now, researchers had been unable to conduct experiments that simulated more naturally occurring levels. But Mehta and co-author Arvind Kumar, a former postdoctoral fellow in his lab, were able to obtain these measurements for the first time using a sophisticated mathematical model they developed and validated with experimental data.

Contrary to what was previously assumed, Mehta and Kumar found that when it comes to stimulating synapses with naturally occurring spike patterns, stimulating the neurons at the highest frequencies was not the best way to increase synaptic strength.

When, for example, a synapse was stimulated with just 10 spikes at a frequency of 30 spikes per second, it induced a far greater increase in strength than stimulating that synapse with 10 spikes at 100 times per second.

"The expectation, based on previous studies, was that if you drove the synapse at a higher frequency, the effect on synaptic strengthening, or learning, would be at least as good as, if not better than, the naturally occurring lower frequency," Mehta said. "To our surprise, we found that beyond the optimal frequency, synaptic strengthening actually declined as the frequencies got higher."

The knowledge that a synapse has a preferred frequency for maximal learning led the researchers to compare optimal frequencies based on the location of the synapse on a neuron. Neurons are shaped like trees, with the nucleus being the base of the tree, the dendrites resembling the extensive branches and the synapses resembling the leaves on those branches.

When Mehta and Kumar compared synaptic learning based on where synapses were located on the dendritic branches, what they found was significant: The optimal frequency for inducing synaptic learning changed depending on where the synapse was located. The farther the synapse was from the neuron's cell body, the higher its optimal frequency.

HEALTH+VE (Potatoes not the dietary villain as claimed)

Potatoes are often painted as villains for dieters, but a new study has found that the staple food is not that bad after all.

Foods like potatoes and white bread with a high glycemic index (GI) are absorbed quickly by the body, triggering a spike in blood pressure.

But a study by researchers at University of Otago found that when you eat these carbohydrates as part of a meal of meat and vegetables the effects are barely felt.

Bernard Venn and his colleagues enlisted 30 healthy young people and monitored the GI levels of three different meals, including one with potatoes as a side dish.
Surprisingly, said Dr Venn, this meal was low on the glycemic index, meaning the food will burn off slowly, even though it contained an ingredient many fear for its potential weight-gain properties.

"I don’t think people should be too afraid of putting high-GI foods into their meals,” Courier Mail quoted Dr Venn as saying.

"Our work suggests that having a small amount of potato with a meal isn’t going to drive your blood sugar crazy,” he added.

The study has been published in the American Journal of Clinical Nutrition.

Best Diet Foods for Weight Loss

Obesity has been a major problem for most of the people around the world. But this should not be a problem for the modern day individuals since there is lot of weight loss diet tips for men and women of all ages. The specialty of the weight loss diet tips for men and women of all ages is that by following such a diet they will be very well able to reduce the excess fat in their body.

By adhering very strictly to such weight loss diet tips for men and women of all ages they can very easily reduce their weight and become hale and healthy. This is the real secret of these weight loss diet tips for men and women of all ages and it needs to be religiously followed on a regular basis. By sticking to a diet that is fully wholesome and nutritious like the inclusion of more green leafy vegetables and drinking lot of water on a daily basis will surely help the burning of the fat. In addition to this the individual needs to avoid junk foods and artificial drinks that are available in the stores that only harm the body. Apart from following such weight loss diet tips for men and women of all ages it would do good if the individuals do some exercise and also yoga  that will be also highly beneficial in reducing the excess fat that is deposited within the body.

The world is flooded with people who really are very obese and want to become very slim by losing the extra bit of fat. There are many people who are on the constant look out for the best diet foods for weight loss. Such people normally visit dieticians to get a very good knowledge about the best diet foods for weight loss. It is to be borne in mind that even by consulting the health experts they would also be able to tell about the best diet foods for weight loss.

By really following such best diet foods for weight loss people can really become slim and also will be able to shed that extra bit of flesh. By sticking to a diet that is rich in vitamins like the leafy vegetables and also greens and also by consuming foods that is rich in vitamin c they will be able to dissolve the fat and remove the waste materials by the anti oxidant properties. Such is the use of the best diet foods for weight loss that will surely do a world of good to any people who will strictly stick to such a diet. Hence the weight loss can be really achieved within a matter of few weeks and the change will be surely noticeable to anyone who would look at the individual. 

Saving Electricity While Playing Online Game

 The federal government of Germany has decided to accelerate change in energy policy. But the transition will succeed only with the help of the consumers. They are called upon to use the energy from renewable resources in a more efficient fashion. A new online game shows how energy can be saved.Do I toast my bread rolls in the oven or over the toaster? Should I heat the water on the stove or in the electric kettle? Do I start the washing machine in the afternoon or after 10 at night? How do I lower CO2 emissions by the way I use energy? Answers to such and similar questions are provided by the online game "RED" -- which is an acronym for "Renewable Energy Drama." Researchers from the Fraunhofer Institute for Digital Media Technology IDMT in Erfurt, Germany, have developed the Web application in the course of the "RESIDENS" project. Together with the Ilmenau University of Technology, the Fraunhofer Application Center System Technology AST, the city utility of the City of Ilmenau as well as the Friedrich Schiller University in Jena, the researchers investigate how consumers of energy can be motivated to use the energy gained from renewable resources more efficiently. The experts see great potential in online games for teaching the subject of "saving electricity at home" in an entertaining manner and to show that one's own behavior can affect how much electricity costs.

"Online games are very well suited to demonstrating situations taken from daily life. The interactive character supports learning very well, since the user receives individual feedback at all times. For this reason, we designed RED as an action-oriented, interactive 3D application," explained Ms. Imke Hoppe, research scientist at IDMT.

The software is targeted at adults and young people interested in renewable energies who want to know how they can save energy. "How much energy do individual household appliances consume, which ones are the energy robbers and are the high bills the results of price increases or are the uplights that are always on the reason for the high bills -- RED supplies the answers. The user does not even have to invest a great deal of time, the game takes only about ten to 15 minutes," says Ms. Hoppe.

RED leads you through the daily life of a fictitious family of three. The screen shows all the rooms in a house. The user goes, via his avatar -- one of the three members of the family -- into each room and is able, via mouse click, to do the regular household chores such as baking food from the freezer or do laundry. If he, for example, clicks on the washing machine, an information box supplies him with information about CO2 generation and the electricity costs for a load of laundry when the machine is full, three quarters full or half full, and it calculates how much this would cost per year.

New Technique for Understanding Quantum Effects in Water

 The use of oxygen isotope substitution will lead to more accurate structural modeling of oxide materials found in everything from biological processes to electronic devices, new research suggests.It covers over two thirds of our planet, is essential for life on Earth and its chemical formula is one of the few most people can name, but we still have much to learn about the structure of H2O. Now, scientists working in Grenoble have developed a new technique using oxygen isotopes to study in detail the structure of disordered oxide materials such as water in biological processes or glasses in lasers and telecommunication devices. This new technique allowed a team from the Institut Laue-Langevin (ILL), University of Bath, Oak Ridge National Laboratory and Stanford University to validate a new theoretical model for water's structure by measuring subtle differences between the molecular organisation of light and heavy water that result from quantum mechanics.

At ILL the structural properties of materials are probed by using neutrons, which act like "super x-rays," via a technique known as neutron scattering. As neutrons pass through materials they are often bounced (or scattered) by atomic nuclei which alters their trajectories, and these scattered neutrons can then be detected to create detailed maps of a sample's molecular structure. To find out more about the positions of particular atoms within a sample, scientists use a trick called isotopic substitution where the scattering length (or ability to bounce neutrons) of a particular element is 'tuned' by substituting one of its isotopes for another. This allows them to zero in on the structure around the atoms of the chosen element.

In modern structural analysis, researchers commonly interchange hydrogen with its heavier isotope deuterium to probe the locations of atoms in water or other hydrogen containing materials. This technique of 'H/D substitution' is also commonly used in the analysis of hydrogen-storage materials or fuel cells. However, there are problems with using H/D substitution in neutron scattering. The lighter hydrogen isotope is comparable in mass to the neutron which generates imprecise scattering data and makes determination of structure more difficult. Also, you can't use H/D substitution to study the difference between the positions of hydrogen atoms in H2O versus deuterium atoms in D2O as the technique assumes that H and D atoms have the same positions. Oxygen has three isotopes: 16O, 17O and 18O and, like hydrogen, is a ubiquitous element on Earth and plays an important role across scientific disciplines. It is often found in structurally disordered materials like silicates in planetary science, glasses for lasers and optical communications, oxide layers in silicon-based electronic devices and water in biological processes. However, it was generally believed that the difference in scattering length between these isotopes is too small to make isotopic substitution with neutron scattering feasible.

The team at ILL challenged this assumption via neutron interferometry -- a technique where neutrons, acting as coherent quantum waves, allow for a very precise measurement of the scattering lengths of atoms in a sample. With the highly sensitive equipment at ILL, the team showed that the difference between the scattering lengths of two of the oxygen isotopes was actually six times larger than the literature suggested. Professor Philip Salmon, from the University of Bath, said: "With this larger contrast, we showed the difference in the scattering lengths of the oxygen isotopes was just about large enough to make neutron scattering a plausible technique for studying the structure of oxide materials." In order to demonstrate the powerful potential of their new technique, the team turned to the structure of the best-known oxide in nature -- liquid water where the imprecise results from hydrogen isotope substitution had created some uncertainty. In particular, the team were interested in comparing structural differences between light water (H2O) and heavy water (D2O).

"The structure and dynamics of water have long been controversial subjects since they can have profound effects on biological processes, and there can be dramatic differences between heavy and light water. For example, most organisms eventually perish in a D2O environment, whereas they thrive in H2O," said Dr Henry Fischer, a physicist at ILL who worked alongside Prof Salmon on this paper.

Using oxygen isotope substitution, Prof Salmon and his team at ILL analyzed the difference between the lengths of the O-H and O-D bonds within water molecules. They found that the O-H bonds were ½ % longer than the O-D bonds -- the first time anyone had measured with such pin-point accuracy this important difference between the molecular structures of light and heavy water.

Their findings were then compared with quantum mechanics predictions using path-integral methods to see if they could clarify some uncertainty around the structural model for liquid water. Earlier mathematical models often assumed simple rigid molecules, where the bond lengths do not vary, but it turns out that such models are not sufficient to account for the quantum effects leading to the observed structural differences between H2O and D2O. Quantum mechanics gives a fuzzy uncertainty to the positions of the H and D atoms in a water molecule, and since D is twice as heavy as H, the fuzzy effect is not as strong for D as compared to H. This leads to the observed structural differences which can be predicted using a more appropriate flexible model for the water molecule. Salmon and his team thus identified the type of theoretical model that is needed for understanding the true structure of water, and confirmed that this model can explain the structural differences between H2O and D2O due to quantum mechanics.

Physicists Move One Step Closer to Quantum Computer

Rice University physicists have created a tiny "electron superhighway" that could one day be useful for building a quantum computer, a new type of computer that will use quantum particles in place of the digital transistors found in today's microchips.In a recent paper in Physical Review Letters, Rice physicists Rui-Rui Du and Ivan Knez describe a new method for making a tiny device called a "quantum spin Hall topological insulator." The device, which acts as an electron superhighway, is one of the building blocks needed to create quantum particles that store and manipulate data.

Today's computers use binary bits of data that are either ones or zeros. Quantum computers would use quantum bits, or "qubits," which can be both ones and zeros at the same time, thanks to the quirks of quantum mechanics.

This quirk gives quantum computers a huge edge in performing particular types of calculations, said Du, professor of physics and astronomy at Rice. For example, intense computing tasks like code-breaking, climate modeling and biomedical simulation could be completed thousands of times faster with quantum computers.

"In principle, we don't need many qubits to create a powerful computer," he said. "In terms of information density, a silicon microprocessor with 1 billion transistors would be roughly equal to a quantum processor with 30 qubits."

In the race to build quantum computers, researchers are taking a number of approaches to creating qubits. Regardless of the approach, a common problem is making certain that information encoded into qubits isn't lost over time due to quantum fluctuations. This is known as "fault tolerance."

The approach Du and Knez are following is called "topological quantum computing." Topological designs are expected to be more fault-tolerant than other types of quantum computers because each qubit in a topological quantum computer will be made from a pair of quantum particles that have a virtually immutable shared identity. The catch to the topological approach is that physicists have yet to create or observe one of these stable pairs of particles, which are called "Majorana fermions" (pronounced MAH-yor-ah-na FUR-mee-ons).

The elusive Majorana fermions were first proposed in 1937, although the race to create them in a chip has just begun. In particular, physicists believe the particles can be made by marrying a two-dimensional topological insulator -- like the one created by Du and Knez -- to a superconductor.

Topological insulators are oddities; although electricity cannot flow through them, it can flow around their narrow outer edges. If a small square of a topological insulator is attached to a superconductor, Knez said, the elusive Majorana fermions are expected to appear precisely where the materials meet. If this proves true, the devices could potentially be used to generate qubits for quantum computing, he said.

Knez spent more than a year refining the techniques to create Rice's topological insulator.