Where did those electrons go? Decades-old mystery solved

The concept of “valence” – the ability of a particular atom to combine with other atoms by exchanging electrons – is one of the cornerstones of modern chemistry and solid-state physics.

Valence controls crucial properties of molecules and materials, including their bonding, crystal structure, and electronic and magnetic properties.

Four decades ago, a class of materials called “mixed valence” compounds was discovered. Many of these compounds contain elements near the bottom of the periodic table, so-called “rare-earth” elements, whose valence was discovered to vary with changes in temperature in some cases. Materials comprising these elements can display unusual properties, such as exotic superconductivity and unusual magnetism.

But there’s been an unsolved mystery associated with mixed valence compounds: When the valence state of an element in these compounds changes with increased temperature, the number of electrons associated with that element decreases, as well. But just where do those electrons go?

Using a combination of state-of-the-art tools, including X-ray measurements at the Cornell High Energy Synchrotron Source (CHESS), a group led by Kyle Shen, professor of physics, and Darrell Schlom, the Herbert Fisk Johnson Professor of Industrial Chemistry in the Department of Materials Science and Engineering, have come up with the answer.

Their work is detailed in a paper, “Lifshitz transition from valence fluctuations in YbAl3,” published in Nature Communications. The lead author is Shouvik Chatterjee, formerly of Shen’s research group and now a postdoctoral researcher at the University of California, Santa Barbara.

To address this mystery, Chatterjee synthesized thin films of the mixed-valence compound of ytterbium – whose valence changes with temperature – and aluminum, using a process called molecular beam epitaxy, a specialty of the Schlom lab. The group then employed angle-resolved photoemission spectroscopy (ARPES) to investigate the distribution of electrons as a function of temperature to track where the missing electrons went.

“Typically for any material, you change the temperature and you measure the number of electrons in a given orbital, and it always stays the same,” Shen said. “But people found that in some of these materials, like the particular compound we studied, that number changed, but those missing electrons have to go somewhere.”

It turns out that when the compound is heated, the electrons lost from the ytterbium atom form their own “cloud,” of sorts, outside of the atom. When the compound is cooled, the electrons return to the ytterbium atoms.

“You can think of it as two glasses that contain some water,” Shen said, “and you’re pouring back and forth from one to the other, but the total amount of water in both glasses remains fixed.”

This phenomenon was first proposed by 20th-century Russian physicist Evgeny Lifshitz, but an answer to the electron mystery hadn’t been proposed until now.

“These findings point toward the importance of valence changes in these material systems. By changing the arrangement of mobile electrons, they can dramatically influence novel physical properties that can emerge,” said Chatterjee.

“This places our understanding of these materials on a better footing,” Shen said.

Other contributors included Ken Finkelstein, senior staff scientist at CHESS; and doctoral students Jacob Ruf and Haofei Wei of the Shen Group. Source: Where did those electrons go? Decades-old mystery solved

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This little robot pill can replace painful injections

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Hello, world: this is WikiTribune

As a big fan of Wikipedia I was very interested to hear that Jimmy Wales was starting a news service. I have, for a very long time, searched for unbiased material for Deskarati in my areas of interest. I have also always personally hankered for a real impartial news service, this has been difficult and recently has been getting worse.

So it was great to hear that Jimmy Wales is trying to produce such a news service, wikitribune. Good luck! Jim – Deskarati

Jimmy Wales

Welcome to WikiTribune, a pilot project for a new approach to journalism where the community is at the center. This is not a news service – yet. It’ll only be the news service I envisage when you play a full role.

When I wrote the very first words in Wikipedia back in January 2001, I chose “Hello, world!”

It is a long standing tradition amongst computer programmers that when you are learning a new programming language, the first thing you do is write a program which says “Hello, world!”

The day I opened Wikipedia to the public, January 15th, 2001, it was not an encyclopaedia – yet. Therefore, that was not the launch of an encyclopaedia.

What was it, then? It was the launch of a project to build an encyclopaedia.

What is this, then? This is the launch of a project to build a news service. An entirely new kind of news service in which the trusted users of the site – the community – is treated as completely equal to the staff of the site – also the community. As with any true wiki, you can jump in and get involved at the highest levels, doing as much or as little as you like to help. As with any successful wiki, there will be detailed discussions and debates by the community to set policy on all the detailed matters that are necessary to build a news service.

My goals are pretty easy to understand, but grand in scope (more fun that way, eh?): to build a global, multilingual, high quality, neutral news service. I want us to be in as many languages as possible as fast as possible. I want us to be more concerned with being right than being first. I want us to report objectively and factually and fairly on the news with no other agenda than this: the ultimate arbiter of the truth is the facts of reality. That’s agenda enough to keep us busy.

So now let me tell you my rough plans for the next few weeks.

If you’re reading this anytime soon after I wrote it, you’re lucky – we aren’t announcing this anywhere and a big part of the point of this letter is to invite journalists who might be excited to write with awe or gleeful disappointment at our launch to relax a notch or two. This is not the launch of a news service. This is the launch of a project to build a news service. That’s why it says “Pilot” right up at the top.

So we’ve just quietly opened up and we plan to be slowly but surely accepting people who have requested an invite. One of the key things that I want to get right from the very beginning is the attitude that we have as a community. Neutrality is non-negotiable. Treating each other well is non-negotiable. This is supposed to be fun. This is supposed to be different. This is supposed to matter.

Over time as we build up activity in the community, we’ll accept more and more people when we are confident that the administrators (some staff, some users) are ready.

We’re using WordPress as the core of our launch platform, and it has some major strengths as a content management system, not least of which is that it is open source and has a mature and strong ecosystem of open source developers. But it also has some major philosophical differences from a wiki – the default assumptions about who can do what are really quite different. So the job of making the software to build our news platform as powerful as we need it to be is going to take some time. Please help me figure out the priorities.

If you’re as excited about this as I am, please do tell a few people, especially people you trust, people you think are smart and kind and might be interested to join our merry band.

Hello, world! Let’s get to work… on WikiTribune.

—Jimbo

JIMMY WALES WIKIPEDIA WIKITRIBUNE

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Lift and Wings

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Andy Serkis Describes Motion Capture

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Could Neanderthals speak?

Forty years ago, the consensus was that they could not. Neanderthals didn’t make cave paintings, or flint arrowheads, and their larynx wasn’t positioned low enough to allow them to make the full range of human vocal sounds.

But more recent discoveries have shown that Neanderthals had a hyoid bone, tongue nerves and hearing range that was very similar to modern humans, and quite different to other primates. Neanderthals also shared the FOXP2 gene with us, which is thought to be involved in speech and language.

Prof Steven Mithen of Reading University has suggested that Neanderthals may have had a ‘proto-language’ that was halfway between speech and music.

Source: Could Neanderthals speak? | Science Focus

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Escherian Staircase Illusion

Via OpticalSpy

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Christening Amazon’s latest wind farm

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Orchid mantis nymphs

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Tesla’s Secret Second Floor

A very interesting article by Greg Reichow at Wired

While working at Tesla, I always enjoyed talking to people after they finished a factory tour. As much as they raved about the amazing automation, gigantic presses, and hundreds of robots, the reality was they only saw half of the actual manufacturing that was taking place in the building. Unknown to most visitors, the factory’s “secret” second floor built many of Tesla’s battery, power electronics, and drive-train systems. It was home to some of the most advanced manufacturing and automation systems in the company. Some of the robots moved at such high speeds that their arms needed to be built from carbon fiber instead of steel.

Though it was obvious why we were building the systems at the heart of our product, such as the battery and motors, many people had difficulty understanding why we manufactured high-voltage cables, displays, fuses, and other smaller systems. Had we spent too much time inhaling the “we know better” fumes of Silicon Valley? Why take on the madness of not only starting a new car company but also making it more vertically integrated than any car company since the heyday of the Ford Rouge plant in the late 1920s?

The answer is simple: Our goal wasn’t to build the best electric vehicle. It was to build the best premium car in the world that just happened to be an EV. This meant integrating technologies that were not readily available. It also meant pushing the boundaries of what was considered “normal” for the design and manufacturing of a car. Furthermore, we needed to do this on an accelerated timeline that most automotive suppliers could not fathom. So, in many cases, this meant building components ourselves. Building your own core components has obvious benefits, but there are some other advantages that you might not immediately recognize.

Speed is the first advantage. Launching a new product presents a team with thousands of small decisions. If you choose to outsource a component, you often need to send people to live in the factory for a prolonged period of time. This means accepting that it’s going to be harder to make choices and to influence outcomes. First, you’re operating within someone else’s environment. Second, you have far less of the product design team available for on-the-spot consultation and decision-making. Nothing beats the ability to have the full engineering team walk into the manufacturing area every day, talk to the people building the products, and gain insights on how to improve. Factory information has a very short half life. Despite what many contract manufacturers promise, the reality of outsourced manufacturing is that you are getting on an airplane to solve problems you could otherwise solve by walking across your building. More here.

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AlphaGo Movie

AlphaGo chronicles a journey from the halls of Cambridge, through the backstreets of Bordeaux, past the coding terminals of DeepMind, to Seoul, where a legendary Go master faces an unproven AI challenger. As the drama unfolds, questions emerge: What can artificial intelligence reveal about a 3000-year-old game? What will it teach us about humanity? http://www.alphagomovie.com/

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Lewis Hamilton was ‘weird’ as a team-mate, says Jenson Button

Great article on the BBC website today for those of us F1 fans. – Jim Deskarati

Jenson Button says he found fellow Briton Lewis Hamilton “a bit weird” when they were team-mates at McLaren.

In his new autobiography, Life at the Limit, the 37-year-old – who was world champion in 2009 – describes Hamilton as “a brilliant, mercurial driver”.

But he says the 32-year-old was “unpredictable” and he “regretted that despite our similarities, we were never really friends”.

Button praises Hamilton for “really coming on over the past few years”.

He added: “He’s matured, become a bit of a statesman and a great representative of the sport.”

Button, who retired at the end of last season but made a one-off return to Formula 1 at the Monaco Grand Prix this year, says he will never race again in F1.

He says the death in 2014 of his father, with whom he was very close and who accompanied him to nearly all his races, had taken the fun out of it.

“I’ve been offered drives in F1 but I’m not interested, although I will race in the future,” Button says. “Just not F1. Not without dad.” Continue reading

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Aluminium Cans Recycling Process

 

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Here Are The Top 10 Most Unnecessary Medical Treatments, According to Scientists

A recent literature study on medical care in the US has put forward ten diagnostic procedures and treatments that were overused in 2016, with the intention of highlighting ways that the medical system could be made more effective and more efficient.

Medicine is often a numbers game. While doctors do a smashing job with limited resources, sometimes striking a balance between time and costs means pills and procedures get prescribed without the patient’s best interests in mind.

“Too often, health care practitioners do not rely on the latest evidence and their patients don’t get the best care,” says researcher Daniel Morgan from the University of Maryland’s School of Medicine.

“Hopefully this study will spread the word about the most overused tests and treatments.”

The team dug through journal articles in the PubMed archive, using search terms such as overuse, overtreatment, inappropriate, and unnecessary. The team considered 2,252 papers, of which 1,224 addressed the overuse of medicine directly. Specifically, the papers reported on “care in which potential harms outweigh potential benefits.”

These were further whittled to 122 papers which were identified as significant. The researchers then agreed on their following ‘top ten’.

Transesophageal echocardiography

In simple terms, this procedure takes pictures of your heart using ultrasound via a tube inserted into your oesophagus. A doctor might use this instead of doing an electrocardiogram, but research suggests any extra detail it might produce isn’t worth the risks of being sedated.

Computed tomography pulmonary angiography

A diagnostic test that images the pulmonary arteries in patients with respiratory symptoms using a CT scan. It isn’t invasive, and is highly sensitive, but hits the patient with a dose of radiation. The wait for this test is likely to result in delays that raise the risk of complications developing.

Computed tomography in any patients with respiratory symptoms

Any kind of CT scan on a patient with non-life threatening respiratory symptoms, according to the study, does little to improve the patient’s outcome. Worse still, these scans raise risks of false positives, where the test indicates a non-existent pathology.

Carotid artery ultrasonography and stenting

Carotid ultrasounds are done to test the width of arteries at the neck, which could help indicate risk of stroke.

Early diagnosis can be a life saver, but the researchers found 9 out of 10 tests being done on asymptomatic patients that resulted in an artery-widening ‘stent’ being inserted were done on inappropriate grounds.

Since stents require surgery, it’s likely a number of these are inflating risk unnecessarily.

Aggressive management of prostate cancer

Prostate cancer is another condition that can be treated easily if found early.

A blood test for markers called prostate antigens can do that, but it’s hard to tell if they’re produced by an aggressive tumour that needs to be dealt with or a slow growing one that the patient can take to their grave in years to come.

Just 1 percent of men who had their prostate removed – risking the complications that go with that – died of the cancer. Of those who kept their prostate? About the same.

Supplemental oxygen for patients with chronic obstructive pulmonary disease

Giving more oxygen to patients with the lung illness COPD didn’t help their lungs work better or improve their wellbeing. But it can cause them to retain carbon dioxide. Which isn’t good.

Surgery for meniscal cartilage tears

Ripping the C-shaped shock-absorbing discs of cartilage inside your knee is no laughing matter. But going to the trouble of repairing it surgically was found to have few benefits that couldn’t be achieved through conservative management and rehabilitation.

Nutritional support in medical inpatients

Overall, malnutrition doesn’t do a patient much good. On the other hand, giving nutritional support to critically ill patients made no difference in terms of hospital stay or mortality, even if it helped them put on weight.

In the event of failing organs or metabolic complications, that support might carry risks that aren’t balanced by benefits.

Use of antibiotics

A 2016 study estimated 506 prescriptions were being written in 2010 to 2011 for every 1000 people. Only 353 could be considered appropriate.

The CDC’s National Action Plan for Combating Antibiotic-Resistant Bacteria aims to reduce inappropriate outpatient antibiotic use by 50 percent within the next few years.

The researchers noted that of the measures in this plan, the most effective was to use social pressures, encouraging doctors to take note of good prescription practices among their colleagues.

Use of cardiac imaging

Cardiac imaging for patients with chest pain was found to have tripled over the past decade, while doing nothing for low-risk patients. This risks leading to unnecessary hospital stays and interventions.

The solution? According to the researchers, doctors should share decision making with their patient.

None of these results should be taken to mean these tests and procedures are to be avoided. We’re not medical professionals at ScienceAlert, so our best advice is – as always – don’t be afraid to ask your doctor.

Research that takes a critical look at how professionals deliver medical care is important for maintaining high standards with available resources.

This research was published in JAMA Internal Medicine. Via ScienceAlert

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SpaceX’s Elon Musk updates Mars plans

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Reflections: Van Eyck and the Pre-Raphaelites

Discover how Jan van Eyck’s ‘Arnolfini Portrait’ was one of the beacons by which the Pre-Raphaelites forged a radical new style. ‘Reflections: Van Eyck and the Pre-Raphaelites’ opens on 2 October.

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Blue Planet II : The Prequel

This world-exclusive introduction to the show is narrated by series presenter Sir David Attenborough and set to an exclusive track developed by Hans Zimmer and Radiohead. The prequel features an array of some of the most awe-inspiring shots and highlights from the new series, as well as several exclusive scenes that will not feature in any of the seven episodes which are set for UK broadcast on BBC One later this year.

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The Headington Shark

The Headington Shark (proper name Untitled 1986) is a rooftop sculpture located at 2 New High Street, Headington, Oxford, England, depicting a large shark embedded head-first in the roof of a house.

The shark first appeared on 9 August 1986. Bill Heine, a local radio presenter who owned the house until 2016, has said “The shark was to express someone feeling totally impotent and ripping a hole in their roof out of a sense of impotence and anger and desperation… It is saying something about CND, nuclear power, Chernobyl and Nagasaki”. The sculpture, which is reported to weigh 4 long hundredweight (200 kg) and is 25 feet (7.6 m) long, fibreglass, is named Untitled 1986 (written on the gate of the house). The sculpture was erected on the 41st anniversary of the dropping of the atomic bomb on Nagasaki. It was designed by sculptor John Buckley and constructed by Anton Castiau, a local carpenter and friend of John Buckley.

For the occasion of the shark’s 21st anniversary in August 2007, it was renovated by the sculptor, following earlier complaints about the condition of the sculpture and the house. On 26 August 2016 Bill Heine’s son Magnus Hanson-Heine bought the house in order to preserve the Headington Shark.

Controversy

Created by sculptor John Buckley, the shark was controversial when it first appeared. Oxford City Council tried to have it taken down on grounds of safety, and then on the ground that it had not given planning permission for the shark, offering to host it at the local swimming pool instead, but there was much local support for the shark. Eventually the matter was taken to the central government, where Tony Baldry, a minister in the Department of the Environment, who assessed the case on planning grounds, ruled in 1992 that the shark would be allowed to remain as it did not result in harm to the visual amenity.

Media appearances

The unexpected shark appeared in a 2002 newspaper advertising campaign for a new financial advice service offered by Freeserve. The advertisement, designed by M&C Saatchi, featured a photograph of the house with the caption “Freedom to find the mortgage that’s right for you”.

In 2013, the sculpture was the subject of an April Fools’ Day story in the Oxford Mail, which announced the establishment of a fictitious £200,000 fund by Oxford City Council to support the creation of similar sculptures on the roofs of other homes in the area.

In 2015, the sculpture was featured in the Channel 4 programme Damned Designs, which focuses on properties that have not followed planning permission. On 1 February 2017 the Headington shark was the answer to a question posed on BBC2’s Eggheads. Via Wiki

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60 perfectly preserved shipwrecks over 2,400 years old have been found in the Black Sea

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Engineers 3-D print high-strength aluminum, solve ages-old welding problem using nanoparticles

HRL Laboratories has made a breakthrough in metallurgy with the announcement that researchers at the famous facility have developed a technique for successfully 3D printing high-strength aluminum alloys—including types Al7075 and Al6061—that opens the door to additive manufacturing of engineering-relevant alloys. These alloys are very desirable for aircraft and automobile parts and have been among thousands that were not amenable to additive manufacturing—3D printing—a difficulty that has been solved by the HRL researchers. An added benefit is that their method can be applied to additional alloy families such as high-strength steels and nickel-based superalloys difficult to process currently in additive manufacturing.

“We’re using a 70-year-old nucleation theory to solve a 100-year-old problem with a 21st century machine,” said Hunter Martin, who co-led the team with Brennan Yahata. Both are engineers in the HRL’s Sensors and Materials Laboratory and PhD students at University of California, Santa Barbara studying with Professor Tresa Pollock, a co-author on the study. Their paper 3D printing of high-strength aluminum was published in the September 21, 2017 issue of Nature.

Additive manufacturing of metals typically begins with alloy powders that are applied in thin layers and heated with a laser or other direct heat source to melt and solidify the layers. Normally, if high-strength unweldable aluminum alloys such as Al7075 or AL6061 are used, the resulting parts suffer severe hot cracking—a condition that renders a metal part able to be pulled apart like a flaky biscuit.

HRL’s nanoparticle functionalization technique solves this problem by decorating high-strength unweldable alloy powders with specially selected . The nanoparticle-functionalized powder is fed into a 3D printer, which layers the powder and laser-fuses each layer to construct a three-dimensional object. During melting and solidification, the nanoparticles act as nucleation sites for the desired alloy microstructure, preventing hot cracking and allowing for retention of full alloy strength in the manufactured part.

Source: Engineers 3-D print high-strength aluminum, solve ages-old welding problem using nanoparticles

 

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