Nyhetsinnsamler

Tool-making may have made language genes more useful

nobel intent - søn, 25/01/2015 - 23:00

It’s widely understood that human genetics can influence culture, but increasingly, the idea that culture can also affect genetics is gaining ground. The theory of gene-culture coevolution suggests that “the cultural practices we adopt change the costs and benefits of having certain genes,” explains Catharine Cross, a researcher at the University of St Andrews. “A gene that is advantageous under one cultural practice is not necessarily advantageous under another.”

For example, yam cultivation in West Africa led to deforestation and an increase in standing water, which creates a breeding ground for mosquitoes and malaria. This meant that yam farmers with a particular genetic resistance to malaria were more likely to survive than farmers with susceptibility to malaria. Yam farmers in the region have been found to have a higher incidence of this genetic trait than nearby groups—even speakers of the same language—who farm other crops.

A recent study published in Nature Communications has suggested that stone tool-making practices among the ancestors of modern humans may have put evolutionary pressure on individuals who weren’t very good at communicating, helping to select for the genes that would become involved in language. The study found that the use of verbal teaching, compared to learning by imitation, significantly improved the quality and speed production of stone tools. This suggests that individuals with gestural or verbal communication skills could have learned to make tools faster and better, giving them an advantage over individuals who could only imitate.

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Updated ice sheet model matches wild swings in past sea levels

nobel intent - søn, 25/01/2015 - 21:30

It has been a bit of a head scratcher. Records of sea level during the last few million years tell us that there have been some warm periods where sea level may have been as much as 20 meters higher than it is today. When fed the conditions that prevailed at the time, however, our computer models of ice sheets haven’t been able to reproduce such a swelling of the ocean.

The models can simulate that much sea level rise, but it requires temperatures much higher than were seen during those warm periods. Realistic losses of ice from Greenland and the fragile, western part of Antarctica (the West Antarctic Ice Sheet) could only provide something in the neighborhood of 3 to 10 meters of sea level rise. That leaves 10 to 17 meters for the East Antarctic Ice Sheet—the largest and most stable ice sheet—to chip in. Convincing the miserly East Antarctic Ice Sheet to be that generous with its contents isn’t easy, which is why the models required such high temperatures.

Updating the models

So what are the models missing? Penn State’s David Pollard and Richard Alley, and University of Massachussetts, Amherst’s Robert DeConto had an idea for something to try. Two things to try, really. They added a pair of physical processes to an ice sheet model that weren’t simulated previously. The first was hydrofracturing. When water reaches the ice sheet from rain or ice melt at the surface, it fills crevasses in the ice.

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The connections in autistic brains are idiosyncratic and individualized

nobel intent - lør, 24/01/2015 - 20:00

The New York Times Magazine recently ran a cover article about mapping the connectome, all of the connections that link all of the neurons in someone's brain. Many of these connections are formed and reinforced as a result of our experiences, and their sum total constitutes everything about our personalities: the memories we've formed, the skills we've learned, the passions that drive us.

There is even data suggesting that some neurological disorders are in fact "connectopathies," characterized by either aberrant connections or an unusual extent of connections among neurons. Some studies have found that autism spectrum disorder (ASD) is associated with decreased functional connectivity in the brain, but other experiments have found increased connectivity in autistic brains. A new study may have reconciled these contradictory findings. Researchers at the Weizmann Institute of Science in Israel determined that brain regions with high interconnectivity in controls have reduced connectivity in ASD, and regions with lower connectivity in controls have elevated connectivity in people with ASD.

The scientists analyzed fMRI scans from high functioning autistic adults and controls, obtained from five different data sets. When the scans from the controls were superimposed upon each other, a typical, canonical template of connectivity was clear. Certain regions had high inter hemispheric (between the right and left sides) connectivity: primary sensory-motor regions like the sensorimotor cortex and the occipital cortex. Others showed low interhemispheric connectivity: regions like the frontal cortex and temporal cortex, which are involved in higher order association. Overall, the control brain scans looked pretty much the same as each other.

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Collapse of Soviet health system may have aided spread of tuberculosis

nobel intent - lør, 24/01/2015 - 16:00

How can you not cry at the end of Baz Luhrmann's Moulin Rouge!, when the courtesan Satine passes away in her lover Christian's arms after he throws money at her and calls her a whore in front of a packed theater only to then learn that she really does love him and had to break up with him to save his life from the wealthy but evil Duke who had sworn to kill him? Yes, it's been foreshadowed by the fact that she had been coughing up blood for the past two hours, but still—it's tragic.

Satine died of consumption—tuberculosis—which was the big microbial menace of the mid-to-late nineteenth century Western world. Why that particular bug, at that particular time and place?

Mycobacterium tuberculosis, the bacterium that causes tuberculosis, can remain latent inside of an infected person for decades. When humans lived in small, isolated bands—as they did until the Neolithic Revolution made agriculture widespread—this was a very effective means of transmission for the bacteria. Once it infected everyone in the group, it had no new victims; so it just hung out, dormant, in the same group of people until those people reproduced. Voila—new victims!

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Study: Complaining on Twitter correlates with heart disease risks

nobel intent - lør, 24/01/2015 - 15:00

This week, a study was released by researchers at the University of Pennsylvania that found a surprising correlation when studying two kinds of maps: those that mapped the county-level frequency of cardiac disease, and those that mapped the emotional state of an area's Twitter posts.

In all, researchers sifted through over 826 million tweets, made available by Twitter's research-friendly "garden hose" server access, then narrowed those down to roughly 146 million tweets that had been posted with geolocation data from over 1,300 counties (each county needed to have at least 50,000 tweets to sift through to qualify). The team then measured an individual county's expected "health" level based on frequency of certain phrases, using dictionaries that had been put through scrutiny over their application to emotional states. Negative statements about health, jobs, and attractiveness—along with a bump in curse words—would put a county in the "risk" camp, while words like "opportunities," "overcome," and "weekend" added more points to a county's "protective" rating.

Not only did this measure correlate strongly with age-adjusted heart disease rate data, it turned out to be a more efficient predictor of higher or lower disease likelihood than "ten classical predictors" combined, including education, obesity, and smoking. Twitter beat that data by a rate of 42 percent to 36 percent.

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[Editorial] Beyond political rhetoric to new ideas for a sustainable NHS

The Lancet - lør, 24/01/2015 - 00:00
Delays in accident and emergency departments across England have featured regularly in the news over the past month. The delays are the worst in a decade and have led several hospitals to declare a major incident because of the pressure on facilities. Compared with the previous winter, departments have seen an increase of 20 000 patients a week, ascribed largely to unrealistic algorithms used by the 111 telephone advice service for patients. Compounding problems are challenges in moving patients out of hospital because of decreased access to social care (estimated to have affected more than 500 000 patients in 2014), staff shortages, and perverse incentives from commissioning contracts that make presentation at an accident and emergency department the final common pathway after other alternatives to receive care have failed.

[Editorial] What are affordable vaccines?

The Lancet - lør, 24/01/2015 - 00:00
Affordability of vaccines prevents many people from accessing the benefits of immunisation, says a new report from Médecins Sans Frontières (MSF) released on Jan 20. Although the world's poorest countries are supported by GAVI, the report describes how a large group of middle-income countries, aid agencies, and GAVI-graduating countries are struggling to afford key vaccinations. For example, in 2014, 78% of low-income countries, but only 56% of middle-income countries, have introduced or intend to introduce pneumococcal conjugate vaccines.

[Editorial] Health care-associated infections in the USA

The Lancet - lør, 24/01/2015 - 00:00
Every day, roughly one in 25 patients in the USA contracts at least one infection during their hospital care—an alarming statistic that is unacceptable in view of the fact that health care-associated infections (HAIs) are mostly preventable. On Jan 14, 2015, the Centers for Disease Control and Prevention (CDC) published the National and State Healthcare-Associated Infections Progress Report that includes infection data from more than 14 500 hospitals and health-care facilities across the USA, showing the progress made and the improvements needed to eliminate HAIs on a state-by-state and national level.

[Comment] Drug-resistance mechanisms and tuberculosis drugs

The Lancet - lør, 24/01/2015 - 00:00
Bedaquiline and delamanid, novel classes of anti-tuberculosis drugs, have been recently approved for the treatment of multidrug-resistant tuberculosis.1 Antimicrobial resistance invariably follows the introduction of new drugs, and appropriate drug-susceptibility testing assays are needed to detect resistance and tailor treatment regimens that contain new agents.2,3 Given that phenotypic drug-susceptibility testing is slow, technically demanding, and, in some cases, unreliable, future assays are likely to be based on rapid molecular techniques.

[Comment] Offline: Progress towards planetary health

The Lancet - lør, 24/01/2015 - 00:00
2014 was the world's hottest year since records began in 1880—0·69°C higher than the 20th-century average, and 0·04°C higher than previous peaks. NASA's Gavin Schmidt was reported last week as saying that these latest findings do “not bode well for a civilisation that is continuing to add greenhouse gases to the atmosphere”. The news came just as Johan Rockström's team at the Stockholm Resilience Centre updated their now famous idea of “planetary boundaries”. In 2009, Rockström proposed the notion of a safe operating space for humanity.

[World Report] Reforming England's National Health Service

The Lancet - lør, 24/01/2015 - 00:00
The 5-year vision for the National Health Service has been widely applauded by health professionals but many are asking how it will work in practice. Emma Wilkinson reports.

[World Report] Concern over private sector tilt in India's new health policy

The Lancet - lør, 24/01/2015 - 00:00
The Indian Government's draft national health policy, which many experts view as a step away from universal health coverage, is out for public consultation. Dinesh C Sharma reports.

[World Report] Twitter campaign highlights top women in global health

The Lancet - lør, 24/01/2015 - 00:00
A social media campaign asking people to nominate leading women in global health is underway with 100 women nominated so far. Sharmila Devi reports.

[Perspectives] Another defining moment for epidemiology

The Lancet - lør, 24/01/2015 - 00:00
Many epidemiologists are obsessed with definitions. A 1978 paper entitled “Definitions of epidemiology” presented 26 of them, documenting how the subject had evolved from an original focus upon epidemics, to infections in populations, and on to broader concerns with all disease in populations. This enthusiasm has continued, culminating for the moment in the sixth edition of the International Epidemiology Association's A Dictionary of Epidemiology, which defines its subject thus: “The study of the occurrence and distribution of health-related events, states, and processes in specified populations, including the study of the determinants influencing such processes, and the application of this knowledge to control relevant health problems.” Many will find this definition awkward—but let us also note that its emphasis is now upon “health”.

[Perspectives] Ingenious inventions

The Lancet - lør, 24/01/2015 - 00:00
During the 19th century a handful of British inventions changed the world, notably railways, electric motors, and chloroform anaesthesia. Some inventions were less revolutionary but remain vital today, such as macadamisation in road-building and the safety bicycle. Yet others worked well for a while, like the Brougham horse-drawn carriage, before becoming redundant with advancing technology. Most inventions never left the drawing board, however. After being registered by their optimistic inventors, they were consigned to the vaults of the UK Government's designs registry at Somerset House in London, and utterly forgotten.

[Perspectives] Yinghao Sun: leader of research on prostate cancer in China

The Lancet - lør, 24/01/2015 - 00:00
For Yinghao Sun, medicine runs in the family. His father was a doctor of internal medicine in a rural army hospital in China's Fujian province where his mother worked in the pharmacy department. “The hospital was very tiny and the majority of the patients were very poor. And that was one of the main reasons that pushed me and helped me decide to study medicine”, he now recalls.

[Perspectives] The historical epidemiology of global disease challenges

The Lancet - lør, 24/01/2015 - 00:00
In response to the spread of Ebola virus disease in west Africa, global public health agencies have scrambled to organise teams to staunch the spiral of infections and have urged researchers in medical anthropology, disaster management, ethics, and other social science fields to formulate ideas for intervention as quickly as possible. The epidemic is by far the worst of the Ebola outbreaks on record that date back to 1976. Yet, it is only one of several deadly viral pathogens—such as yellow fever, dengue, and influenza—that have repeatedly scourged populations in west Africa.

[Obituary] Robert Frederick Schilling

The Lancet - lør, 24/01/2015 - 00:00
Haematologist and inventor of the Schilling test. He was born in Adell, WI, USA, on Jan 19, 1919, and died in Madison, WI, USA, on Sept 30, 2014, aged 95 years.

[Correspondence] Effects of long-term use of cardiovascular drugs

The Lancet - lør, 24/01/2015 - 00:00
Millions of people are prescribed drugs to prevent and treat cardiovascular disease for decades, even though the long-term safety and efficacy of these drugs are unknown. Introduction of the polypill (typically containing aspirin, statin, beta-blocker, and angiotensin-converting-enzyme inhibitor) without evidence of its long-term effects provides an additional challenge.

[Correspondence] Dual antiplatelet treatment after stenting

The Lancet - lør, 24/01/2015 - 00:00
With great interest, we read the study by Jean-Philippe Collet and colleagues (Nov 1, p 1577)1 who found no ischaemic benefit for extension of dual antiplatelet treatment (DAPT) beyond 1 year after stenting with drug-eluting stent (DES) when no event has occurred within the first year after stenting. By contrast, a strategy of prolongation of DAPT for up to 2 years might be harmful because of increased major or minor bleedings in the continuation group.2