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Physics Experiment With Ultrafast Laser Pulses Produces a Previously Unseen Phase of Matter

Slashdot - Science - Mar, 12/11/2019 - 21:30
An anonymous reader quotes a report from Phys.Org: Adding energy to any material, such as by heating it, almost always makes its structure less orderly. Ice, for example, with its crystalline structure, melts to become liquid water, with no order at all. But in new experiments by physicists at MIT and elsewhere, the opposite happens: When a pattern called a charge density wave in a certain material is hit with a fast laser pulse, a whole new charge density wave is created -- a highly ordered state, instead of the expected disorder. The surprising finding could help to reveal unseen properties in materials of all kinds. The experiments made use of a material called lanthanum tritelluride, which naturally forms itself into a layered structure. In this material, a wavelike pattern of electrons in high- and low-density regions forms spontaneously but is confined to a single direction within the material. But when hit with an ultrafast burst of laser light -- less than a picosecond long, or under one trillionth of a second -- that pattern, called a charge density wave or CDW, is obliterated, and a new CDW, at right angles to the original, pops into existence. This new, perpendicular CDW is something that has never been observed before in this material. It exists for only a flash, disappearing within a few more picoseconds. As it disappears, the original one comes back into view, suggesting that its presence had been somehow suppressed by the new one. The study has been published in the journal Nature Physics.

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UCLA Now Has the First Zero-Emission, All-Electric Mobile Surgical Instrument Lab

Slashdot - Science - Mar, 12/11/2019 - 19:55
UCLA's new mobile surgical lab is a zero-emission, all-electric vehicle that will move back and forth between two UCLA campuses, collecting, sterilizing and repairing surgical instruments for the medical staff there. TechCrunch reports: Why is that even needed? The usual process is sending out surgical instruments for this kind of service by a third-party, and it's handled in a dedicated facility at a significant annual cost. UCLA Health Center estimates that it can save as much as $750,000 per year using the EV lab from Winnebago instead. The traveling lab can operate for around eight hours, including round-trips between the two hospital campuses, or for a total distance traveled of between 85 and 125 miles on a single charge of its battery, depending on usage. It also offers "the same level of performance, productivity and compliance" as a lab in a fixed-location building, according to Winnebago.

Read more of this story at Slashdot.

Individual climate models may not provide the complete picture

Science Daily - Mar, 12/11/2019 - 15:49
Equilibrium climate sensitivity -- how sensitive the Earth's climate is to changes in atmospheric carbon dioxide -- may be underestimated in individual climate models, according to a team of climate scientists.

Deep neural networks speed up weather and climate models

Science Daily - Mar, 12/11/2019 - 15:49
A team of environmental and computation scientists is using deep neural networks, a type of machine learning, to replace the parameterizations of certain physical schemes in the Weather Research and Forecasting Model, an extremely comprehensive model that simulates the evolution of many aspects of the physical world around us.

New material points toward highly efficient solar cells

Science Daily - Mar, 12/11/2019 - 15:49
A new type of material for next-generation solar cells eliminates the need to use lead, which has been a major roadblock for this technology.

Why only some post-stroke survivors can 'copy what I say'

Science Daily - Mar, 12/11/2019 - 15:02
Researchers report that the left lateral temporal cortex must be intact in stroke patients with aphasia if they are to have their speech entrained. In speech entrainment, stroke survivors practice fluent speech production by following along with another speaker.

Flame-retardant exposure increases anxiety, affects social behaviors in prairie vole

Science Daily - Mar, 12/11/2019 - 15:02
New research shows that early life exposure to a commonly used flame-retardant mixture increases anxiety and affects socioemotional behaviors in prairie voles, particularly in females.

Some hoppy news: Hops don't need to go dormant in order to flower

Science Daily - Mar, 12/11/2019 - 15:02
In a study that wraps up three years and 13 growth cycles of several popular hop varieties, researchers are upending conventional wisdom hop growers have followed for decades to coax their plants to flower. His results open up new possibilities for indoor, sustainable, local production of hops.

Detecting tiny amounts of fentanyl

Science Daily - Mar, 12/11/2019 - 15:02
Researchers have designed a promising new tool that can identify smaller concentrations of drug powders than any other device. Portable, simple to use, and cost effective, the technology could provide law enforcement officers and forensic chemists a quick and accurate way to identify unknown, potentially dangerous, substances.

Army researcher promotes cooperation between humans, autonomous machines

Science Daily - Mar, 12/11/2019 - 15:02
The trust between humans and autonomous machines is a research priority -- as machines become integral to society, it is critical to understand the impact on human decision-making.

Half of Piedmont drinking wells may exceed NC's hexavalent chromium standards

Science Daily - Mar, 12/11/2019 - 15:02
A new study which combines measurements from nearly 1,400 drinking water wells across North Carolina estimates that more than half of the wells in the state's Piedmont region contain levels of cancer-causing hexavalent chromium in excess of state safety standards. The prediction is based on a model of geology and chemistry.

Cells control their dance of death

Science Daily - Mar, 12/11/2019 - 13:29
Researchers have revealed for the first time how white blood cells control the final moments of their death, helping their own removal from the human body.

Iron-based solar cells on track to becoming more efficient

Science Daily - Mar, 12/11/2019 - 13:29
An international study shows that 30% of the energy in a certain type of light-absorbing iron molecule disappears in a previously unknown manner. By closing this loophole, the researchers hope to contribute to the development of more efficient solar cells using this iron-based solar cell.

Study reveals 'bug wars' that take place in cystic fibrosis

Science Daily - Mar, 12/11/2019 - 13:29
Scientists have revealed how common respiratory bugs that cause serious infections in people with cystic fibrosis interact together, according to a new study.

Good noise, bad noise: White noise improves hearing

Science Daily - Mar, 12/11/2019 - 13:29
White noise is not the same as other noise -- and even a quiet environment does not have the same effect as white noise. With a background of continuous white noise, hearing pure sounds becomes even more precise, as researchers have shown. Their findings could be applied to the further development of cochlear implants.

Study reveals breach of 'dancing' barrier governs crystal growth

Science Daily - Mar, 12/11/2019 - 13:29
Researchers used computer-based simulations to analyze how atoms and molecules move in a solution and identified a general mechanism governing crystal growth that scientists can manipulate when developing new materials.

A milestone in ultrashort-pulse laser oscillators

Science Daily - Mar, 12/11/2019 - 13:23
With the demonstration of a sub-picosecond thin-disk laser oscillator delivering a record-high 350-W average output power, physicists set a new benchmark and pave the path towards even more powerful lasers.

Widespread misinterpretation of gene expression data

Science Daily - Mar, 12/11/2019 - 13:09
Reproducibility is a major challenge in experimental biology. New research identifies a frequent technical bias in data generated by RNA-seq technology, which allows in a single test the simultaneous measurement of the expression level of all the genes in a given sample. This bias recurrently leads to false results.

Songbirds sing species-specific songs

Science Daily - Mar, 12/11/2019 - 13:09
The generation of species-specific singing in songbirds is associated with species-specific patterns of gene activity in brain regions called song nuclei, according to a new study. According to the authors, the findings could be a promising step toward a better understanding of the contribution of multiple genes to the evolution of behaviors.

Carbon nanotubes show a love/hate relationship with water

Science Daily - Mar, 12/11/2019 - 12:04
New research reveals that carbon nanotubes (CNTs) as a coating can both repel and hold water in place, a useful property for applications like printing, spectroscopy, water transport, or harvesting surfaces. When water is dropped on a CNT forest, the CNTs repel the water, and it forms a sphere. However, when flipped over, the drop does not fall to the ground but rather clings to the surface.


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