Nyhetsinnsamler

Researchers: Forget old experiments, let’s reinvent the wheel

nobel intent - lør, 26/07/2014 - 18:15
Beamsplitters like these are enough to confirm that single photons can be linearly polarized. Fermilab

One of the joys of the arXiv is that anyone can submit anything to the website. Cranks and kooks can publish to their hearts' content in the theoretical physics section. Their work will remain there, read only by those searching for casual amusement. Yet somewhere between all the excellent science and slapstick comedy are scientists who just get stuff flat out wrong.

This is the story of how two respected physicists failed to understand photon angular momentum. Don't worry, they're not alone. Every physicist who has given the subject any thought has lost sleep working it out (and has had nightmares involving Jackson's Classical Electrodynamics). Since I lost sleep over it, I figured I would ensure that you all lose some sleep too.

Spinning photons and rotating electric fields

The fundamental confusion arises from the fact that there are two equivalent ways of describing the angular momentum of a photon. A cursory inspection of nature, however, seems to reveal that one is more natural than the other.

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Massive impacts show asteroid has deep crust

nobel intent - lør, 26/07/2014 - 16:07
Artist's impression of the huge impact that deformed the protoplanetary asteroid Vesta, leaving the large impact basin we see today. Martin Jutzi

A new study shows that the asteroid 4 Vesta may have a different internal structure than previously thought. Vesta, the second largest body in the asteroid belt after the dwarf planet Ceres, is notable for two gigantic craters, so big that they partly overlap despite being on opposite poles of the asteroid.

The first, chronologically speaking, is called Venenia (Named for a priestess of the goddess Vesta in Roman mythology), the result of an impact some 2 billion years ago. The crater is 395 kilometers in diameter, but only penetrated about 25 kilometers deep into the surface of Vesta. And then there’s Rheasilvia. Also named for a priestess of Vesta, Rheasilvia is a whopping 505 km in diameter (Vesta is only 525km in diameter), and the rim of the crater is also one of the tallest mountains in the solar system. Rheasilvia was probably created about one billion years ago, and it obliterated part of Venenia where the two overlap.

The impact penetrated so deep that it’s thought to reach down through the asteroid’s crust to its mantle. The new study, however, shows that, while it did reach about 60-100 km, it did not penetrate to the mantle, suggesting the mantle begins deeper than previously thought.

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[This Week in Medicine] July 26–August 1, 2014

The Lancet - lør, 26/07/2014 - 02:01
Child obesity is on the rise in Northern Ireland. According to a Royal College of Paediatrics and Child Health (RCPCH) survey, almost 20% of children in Northern Ireland are overweight or obese before they start primary school, because many lead sedentary lifestyles. RCPCH is opening an office in Belfast to help improve children's health.

[Editorial] Making primary care people-centred: a 21st century blueprint

The Lancet - lør, 26/07/2014 - 02:01
Not since the Alma-Ata definition of primary care in 1978 has there been so much soul searching on how best to provide a first-contact system that is fair, equitable, accessible, cost effective, sustainable, and above all improves the health and wellbeing of the population it serves. Part of this renewed attention on primary care is the widespread feeling, in high-income countries in particular, that there is an impending crisis with not enough general practitioners, an increasingly unsustainable workload, underfunding by governments, fragmentation between primary and secondary or tertiary services, and a changing burden of disease and risk factor profile in populations.

[Editorial] STOP TB—moving out and moving on

The Lancet - lør, 26/07/2014 - 02:01
Last week, the STOP TB Partnership, a coalition of more than 1000 partner organisations that coordinate and lead advocacy efforts against tuberculosis, unexpectedly announced it will move its Secretariat from WHO to the UN Office for Project Services in early 2015. Since 2001, when the STOP TB Partnership was established, WHO has hosted the organisation and provided all its administrative services. So why has the partnership decided to move and how will the way it operates change?

[Editorial] The real meaning of US hospital rankings

The Lancet - lør, 26/07/2014 - 02:01
On July 15, the US News & World Report, in association with the research organisation RTI International, published its 25th annual ranking of the nation's best hospitals for 2014–15. These national rankings name the top 50 or so hospitals in key specialties, including cancer, cardiology, and respiratory medicine. Much attention in the report focuses on the top-ranked hospitals, which include the Mayo Clinic, Massachusetts General Hospital, and Johns Hopkins. Some of the best hospitals are located in the wealthiest American states, such as California, Massachusetts, and New York.

[Comment] More multiarm randomised trials of superiority are needed

The Lancet - lør, 26/07/2014 - 02:01
Well-designed and well-conducted randomised controlled trials (RCTs) are the most reliable way to identify safe, superior treatments. Many bureaucratic and practical challenges face today's RCTs, increasing the time and cost required. A key problem is the relatively small number of superiority trials (25–50%) that report success—ie, that the new treatment is better than the control.). We argue for a cultural shift to multiarm, phase 3 superiority RCTs.

[Comment] Etrolizumab in moderate-to-severe ulcerative colitis

The Lancet - lør, 26/07/2014 - 02:01
In The Lancet, Séverine Vermeire and colleagues report the results of a double-blind, randomised, placebo-controlled phase 2 trial that studied the effects of etrolizumab—a humanised monoclonal antibody that selectively binds the β7 subunit of both the α4β7 and αEβ7 integrins—on the induction of remission in patients with moderate-to-severe ulcerative colitis. 124 patients were randomised, and clinical remission at week 10 (the primary endpoint) was achieved in a significantly higher proportion of patients in the etrolizumab groups than in the placebo group (eight patients of 39 analysed in the etrolizumab 100 mg group [21%, 95% CI 7–36], four of 39 in the etrolizumab 300 mg plus loading dose group [10%, 0·2–24], and none of 41 patients in the placebo group).

[Comment] New era for treatment in differentiated thyroid cancer

The Lancet - lør, 26/07/2014 - 02:01
Multikinase inhibitors were introduced into clinical trials for radioactive iodine-refractory differentiated thyroid cancer a decade ago. In The Lancet, Marcia Brose and colleagues report the results of DECISION, the first phase 3 randomised, double-blind, placebo-controlled clinical trial with the multikinase inhibitor sorafenib in differentiated thyroid cancer. On the basis of this landmark trial, sorafenib received an orphan designation by the European Medicine Agency in differentiated thyroid cancer, and was approved by the US Food and Drug Administration (FDA) for treatment of radioactive iodine-refractory differentiated thyroid cancer in November, 2013.

[Comment] Tissue engineering's green shoots of disruptive innovation

The Lancet - lør, 26/07/2014 - 02:01
The ready availability of tissues or organs to replace or repair those diseased or damaged is a ubiquitous clinical need, and the rapidly developing field of tissue engineering might offer innovative solutions. Two Articles in The Lancet show the incremental expansion of the applications of tissue-engineering technology to reconstructive surgery.

[Comment] The Wakley Essay Prize 2014: the best of both worlds

The Lancet - lør, 26/07/2014 - 02:01
In the pilot episode of Star Trek, Captain Pike, troubled by the stresses of command, solicits the advice of his ship's medic. The doctor reaches for what at first appears to be some futuristic piece of medical technology, but which opens up to reveal a portable cocktail kit. “Sometimes a man will tell his bartender things he'll never tell his doctor”, he explains. While The Lancet would never recommend a trip to the nearest hostelry as a treatment option, the Enterprise's doctor has a point. Even the most state-of-the-art biomedical investigations and management can only be effective when guided by a good working relationship between health professional and patient.

[Comment] Highlights 2014: picturing health

The Lancet - lør, 26/07/2014 - 02:01
Once again we invite readers to submit their photographs to The Lancet's annual Highlights competition. We are looking for striking images on any topic in medicine, from global health to clinical medicine, from the individual person to populations. You might want to highlight a beautiful image that captures an aspect of your research, or one that conveys a powerful truth about global health. We are interested in photographs from any country; among the winning photographs last year were the hopeful faces of children in Rwanda, a vibrant hospital mural in Haiti, a gram stain of sputum from a patient with cystic fibrosis in Australia, and records to measure child health in Zambia.

[Comment] Offline: The moribund body of medical history

The Lancet - lør, 26/07/2014 - 02:01
A former editor of one notable American medical journal once said that an interest in the medical past was a sign that one no longer had anything useful to contribute to medicine's future. This view reflects the way some physicians see historical progress in their chosen specialty—like stamp collecting, accumulating and displaying one discovery after another to illustrate the collective force of past achievement. But the discipline of medical history has more to offer than simply an album of colourful inventions.

[World Report] MH17 tragedy: HIV community mourns loss of colleagues

The Lancet - lør, 26/07/2014 - 02:01
Organisers of this year's International AIDS Conference dedicated the meeting to the delegates who were killed on ill-fated flight MH17. Udani Samarasekera reports.

[World Report] Anthrax and smallpox errors highlight gaps in US biosafety

The Lancet - lør, 26/07/2014 - 02:01
The US Centers for Disease Control and Prevention and other federal agencies are in the dock over serious lapses in their handling of dangerous pathogens. Brian Owens reports.

[World Report] UK general practice in crisis: time for a rethink?

The Lancet - lør, 26/07/2014 - 02:01
Primary care in the UK is in crisis and requires a radical restructuring if it is to manage increasing patient demand amid cuts in resources, say experts. Emma Wilkinson reports.

[Perspectives] We are the dead

The Lancet - lør, 26/07/2014 - 02:01
Despite its cool modernist design and layout, there's an aura of transgression about Richard Barnett's The Sick Rose: Or; Disease and the Art of Medical Illustration. The inclusion of an image from Mary Shelley's Frankenstein is accompanied by the comment that, as did its titular character, 19th-century medicine “was learning to dismantle the body, to subvert its integrity, even to rethink the meaning of life and death”. It is a remarkably perceptive reading of Shelley's novel, in which the actual creation of the creature is vague, but the nightmarish guilt and denial of Frankenstein is vividly written, suggesting that for man to infuse vitality into a corpse is as great a misdemeanour as murder.

[Perspectives] What is the alternative?

The Lancet - lør, 26/07/2014 - 02:01
In her late 40s my mother developed multiple sclerosis. One of the ways she tried to make sense of what was happening to her was to consult a homoeopath. I have always been thankful that he offered her only two pieces of advice—both of which she took. The first was to essentially rely upon orthodox medicine (in which he had previously practised). The second to offer her a prescription that purported to prevent influenza (she had been advised to avoid infections). In the early 1980s, there wasn't a lot that regular medicine could offer for patients with multiple sclerosis but I feel her doctors followed the cardinal Hippocratic rule of doing no harm.

[Perspectives] Polio provocation: solving a mystery with the help of history

The Lancet - lør, 26/07/2014 - 02:01
During the summer of 1951, a medical mystery in the USA erupted into a crisis, stimulating professional debate and public anxiety. The issue was polio provocation, a health risk facing unvaccinated children in polio endemic regions. Leading specialists were at a loss to explain the condition. As the poliovirus was widespread before the discovery of an effective vaccine in 1955, evidence that some paediatric injections could incite polio infection and paralysis led to extraordinary shifts in health policy and calculated efforts to mitigate the risk.