Nature News

Diskutera fysik, kemi, biologi, samt direkta tillämpningar såsom teknik och medicin.
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Året som gått

Inlägg av Tryggve » fre 27 dec 2013, 23:38

Nature News har ett slags sammanfattningsnummer över året som gått.

http://www.nature.com/news/specials/201 ... S-20131224

Natures 10.
Nature profiles ten people who were central in some of the most important science stories this year: from Feng Zhang, who is advancing gene-editing techniques to Henry Snaith, who is developing new solar-cell materials.
http://www.nature.com/news/365-days-nature-s-10-1.14367


Årets bilder:
http://www.nature.com/news/365-days-ima ... ar-1.14303

Lite funderingar om händelser inom vetenskap o forskning under året.
http://www.nature.com/news/365-days-201 ... ew-1.14366

God fortsättning och Gott Nytt År, förresten. :-)

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Re: Året som gått

Inlägg av pwm » lör 28 dec 2013, 23:53


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Re: Året som gått

Inlägg av Tryggve » sön 29 dec 2013, 14:36

pwm skrev:
Wow!
Kan bara instämma i det. Riktigt snyggt. :-)

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Re: Nature News

Inlägg av devadatta » sön 29 dec 2013, 15:56

Fina bilder! Får se hur lång tid det tar innan new ageare hänvisar till forskningen bakom bilden "Flower power".

Bild

These images show faint electric fields around an idealized flower. UK researchers found that bees sense these fields: one bee leaves a positive charge behind and others can use it to decide whether to visit the flower.
Vetenskap - det är roligt för att det är sant!

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Rättsmedicin

Inlägg av Tryggve » fre 07 feb 2014, 14:39

Lite nya saker.

En artikel handlar om brister i rättsmedicinska analyser i 'USA, och att man vill införa standarder för hur arbete ska bedrivas.

Faulty forensic science under fire

US panels aim to set standards for crime labs.

For 19 years, Gerard Richardson sat in prison in New Jersey wondering how forensics experts had got his case so wrong. His conviction for a 1994 murder was based on a bite mark on the victim’s body that seemed to match his own teeth; it was the main physical evidence linking him to the crime. Last year, he was exonerated when DNA taken from the same bite mark turned out not to be his. According to the Innocence Project in New York, which tracks wrongful convictions, more than half of DNA exonerations involve faulty forensic evidence from crime labs and unreliable methods such as bite-mark analysis.

Cases such as Richardson’s are one reason why the US Department of Justice and the National Institute of Standards and Technology (NIST) have now created the first US national commission on forensic science. The panel of 37 scientists, lawyers, forensics practitioners and law-enforcement officials met for the first time this week in Washington DC, and aims to advise on government policies such as training and certification standards. In March, NIST will begin to set up a parallel panel, a forensic-science standards board that will set specific standards for the methods used in crime labs.
Faulty forensic science under fire

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Re: Nature News

Inlägg av Tryggve » fre 07 feb 2014, 14:42

Vilket också gjorde att jag hittade detta länk med tema rättsmedicin/analyser

Science in court.

http://www.nature.com/news/specials/sci ... index.html
Forensic science evolved less as a conventional academic discipline and more as a service driven by the needs of law enforcement. As a result, the vast majority of its day-to-day tools — from fingerprint analysis to hair- and fibre-matching — have developed without the influence and scrutiny of conventional academic research. In this special, Nature examines the gap between academia and the forensic lab, and explores ways in which the two areas can come together to put science in court on a stronger footing.

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Svante Pääbo

Inlägg av Tryggve » fre 07 feb 2014, 20:02

Svante Pääbo verkar ha skrivit sina memoarer. Recension i Nature.

http://www.nature.com/nature/journal/v5 ... E-20140206
Henry Gee relishes the memoir of Svante Pääbo, a leader in the field of ancient DNA.

Neanderthal Man: In Search of Lost Genomes

At a Royal Society meeting in London last year, just weeks before the publication in these pages of a high-quality Neanderthal genome (K. Prüfer et al. Nature 505, 43–49; 2014), David Reich — one of the paper's authors — spoke of “introgression” between Neanderthals, Homo sapiens and other hominins. This irked a member of the audience. “Are you telling me,” he asked, in cut-glass tones, “that these different species copulated with one another?” I was seized by an impulse to stand up and reply, in similarly stentorian fashion, “Not only did they copulate, but their union was blessed with issue!” (I stayed in my seat.)

The study of human origins and evolution currently stands on a cusp. For decades we have had to make do with bones and stones, thin gruel from which to craft a narrative. Now we can extract DNA from fossils. Not just in bits and pieces, each as enigmatic as a broken tooth or a chipped stone flake — but entire genomes. Unlike fossils, genomes can tell stories. They can legitimately link species into skeins of common ancestry and descent.

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Clovisgenom

Inlägg av Tryggve » tor 13 feb 2014, 19:02

Man har sekvenserat genomet hos en individ från den sk Clovis-kulturen i USA.
The genome of a Late Pleistocene human from a Clovis burial site in western Montana

Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 14C years before present (bp) (13,000 to 12,600 calendar years bp)1, 2. Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the North American ice sheets from an ancestral technology3. However, both the origins and the genetic legacy of the people who manufactured Clovis tools remain under debate. It is generally believed that these people ultimately derived from Asia and were directly related to contemporary Native Americans2. An alternative, Solutrean, hypothesis posits that the Clovis predecessors emigrated from southwestern Europe during the Last Glacial Maximum4. Here we report the genome sequence of a male infant (Anzick-1) recovered from the Anzick burial site in western Montana. The human bones date to 10,705 ± 35 14C years bp (approximately 12,707–12,556 calendar years bp) and were directly associated with Clovis tools. We sequenced the genome to an average depth of 14.4× and show that the gene flow from the Siberian Upper Palaeolithic Mal’ta population5 into Native American ancestors is also shared by the Anzick-1 individual and thus happened before 12,600 years bp. We also show that the Anzick-1 individual is more closely related to all indigenous American populations than to any other group. Our data are compatible with the hypothesis that Anzick-1 belonged to a population directly ancestral to many contemporary Native Americans. Finally, we find evidence of a deep divergence in Native American populations that predates the Anzick-1 individual.
http://www.nature.com/nature/journal/v5 ... 13025.html

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Publikationer dras tillbaka

Inlägg av Tryggve » tis 25 feb 2014, 16:29

Tja, vad ska man säga. Över 120 publikationer (nonsenpublikationer, antar jag att man ska översätta det med) dras tillbaka. Det rör sig till största delen om abstracts till konferenser. Motivet till varför de skickats in kan vara något oklart också. Möjligen bedrägeri för att få in konferensavgifter?


http://www.nature.com/news/publishers-w ... rs-1.14763

Publishers withdraw more than 120 gibberish papers


Conference proceedings removed from subscription databases after scientist reveals that they were computer-generated.


The publishers Springer and IEEE are removing more than 120 papers from their subscription services after a French researcher discovered that the works were computer-generated nonsense.

Over the past two years, computer scientist Cyril Labbé of Joseph Fourier University in Grenoble, France, has catalogued computer-generated papers that made it into more than 30 published conference proceedings between 2008 and 2013. Sixteen appeared in publications by Springer, which is headquartered in Heidelberg, Germany, and more than 100 were published by the Institute of Electrical and Electronic Engineers (IEEE), based in New York. Both publishers, which were privately informed by Labbé, say that they are now removing the papers.

Among the works were, for example, a paper published as a proceeding from the 2013 International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering, held in Chengdu, China. (The conference website says that all manuscripts are “reviewed for merits and contents”.) The authors of the paper, entitled ‘TIC: a methodology for the construction of e-commerce’, write in the abstract that they “concentrate our efforts on disproving that spreadsheets can be made knowledge-based, empathic, and compact”. (Nature News has attempted to contact the conference organizers and named authors of the paper but received no reply; however at least some of the names belong to real people. The IEEE has now removed the paper).

How to create a nonsense paper

Labbé developed a way to automatically detect manuscripts composed by a piece of software called SCIgen, which randomly combines strings of words to produce fake computer-science papers. SCIgen was invented in 2005 by researchers at the Massachusetts Institute of Technology (MIT) in Cambridge to prove that conferences would accept meaningless papers — and, as they put it, “to maximize amusement” (see ‘Computer conference welcomes gobbledegook paper’). A related program generates random physics manuscript titles on the satirical website arXiv vs. snarXiv. SCIgen is free to download and use, and it is unclear how many people have done so, or for what purposes. SCIgen’s output has occasionally popped up at conferences, when researchers have submitted nonsense papers and then revealed the trick.

Labbé does not know why the papers were submitted — or even if the authors were aware of them. Most of the conferences took place in China, and most of the fake papers have authors with Chinese affiliations. Labbé has emailed editors and authors named in many of the papers and related conferences but received scant replies; one editor said that he did not work as a program chair at a particular conference, even though he was named as doing so, and another author claimed his paper was submitted on purpose to test out a conference, but did not respond on follow-up. Nature has not heard anything from a few enquiries.

“I wasn’t aware of the scale of the problem, but I knew it definitely happens. We do get occasional e-mails from good citizens letting us know where SCIgen papers show up,” says Jeremy Stribling, who co-wrote SCIgen when he was at MIT and now works at VMware, a software company in Palo Alto, California.

“The papers are quite easy to spot,” says Labbé, who has built a website where users can test whether papers have been created using SCIgen. His detection technique, described in a study1 published in Scientometrics in 2012, involves searching for characteristic vocabulary generated by SCIgen. Shortly before that paper was published, Labbé informed the IEEE of 85 fake papers he had found. Monika Stickel, director of corporate communications at IEEE, says that the publisher “took immediate action to remove the papers” and “refined our processes to prevent papers not meeting our standards from being published in the future”. In December 2013, Labbé informed the IEEE of another batch of apparent SCIgen articles he had found. Last week, those were also taken down, but the web pages for the removed articles give no explanation for their absence.

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Vacciner

Inlägg av Tryggve » ons 26 feb 2014, 12:35

Inlägg 6666. Kanske dags att ta en paus nu. Får se.

Nå, det passar ju att detta handlar lite om värme då kanske.

Under en vaccinationskampanj i Benin så upptäckte man att det vaccin som användes inte behövde hållas kallt för att bevaras. Vilket gör att man undrar hur nödvändigt det är med kylväskor.
(Det beror nog rimligen på, antar jag).

http://www.nature.com/news/vaccines-end ... S-20140225
Vaccines endure African temperatures without damage

Anti-meningitis campaign in Benin delivers more than 150,000 doses with no losses from excess heat.

An immunization campaign in West Africa has shown that vaccines can be delivered to remote areas without using ice boxes, and still remain viable. The finding challenges decades-old dogma that vaccines must be kept cool at every step of the chain from manufacture to use.

Julien Potet, a vaccines-policy adviser at Médecins Sans Frontières (MSF; also known as Doctors Without Borders) in Paris, says that the findings set "a very positive precedent". He recounts how an MSF campaign in Chad in 2010 that vaccinated half a million people against measles required 22,000 ice packs in just 11 days. "If you eliminate the need for icepacks from vaccine carriers in the last stretch of a vaccine’s journey, it would help us reach more kids, much more easily," he says.

The anti-meningitis campaign, carried out in Benin in December 2012 by the country's health ministry and researchers from the World Health Organization (WHO) and PATH, a non-profit body based in Seattle, Washington, tested delivering a vaccine against deadly meningococcal meningitis A that was stored at temperatures of up to 40 °C for up to four days. Its findings, published today in Vaccine1, mark an unequivocal success, with only 9 of the more than 15,000 vials needing to be discarded, none of them for heat damage.
`

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Re: Nature News

Inlägg av Blafsen » ons 26 feb 2014, 12:45

Tryggve skrev:Inlägg 6666. Kanske dags att ta en paus nu. Får se.
Begäran avslagen. Enälligt beslut.
......men jag är inte smartare än en femteklassare.

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Re: Nature News

Inlägg av Tryggve » ons 12 mar 2014, 20:21

Denna artikel ligger nog bakom en betalvägg, men den lät väldigt intressant, så jag tänkte att jag i alla fall borde nämna den. Man har sekvenserat genomet hos en 7000 år gammal individ från dagens Spanien. Detta för att det ska vara före jordbrukets införande, och att man då skulle kunna se vilka adaptioner som har skett efter jordbrukets införande.
Derived immune and ancestral pigmentation alleles in a 7,000-year-old Mesolithic European

Ancient genomic sequences have started to reveal the origin and the demographic impact of farmers from the Neolithic period spreading into Europe1, 2, 3. The adoption of farming, stock breeding and sedentary societies during the Neolithic may have resulted in adaptive changes in genes associated with immunity and diet4. However, the limited data available from earlier hunter-gatherers preclude an understanding of the selective processes associated with this crucial transition to agriculture in recent human evolution. Here we sequence an approximately 7,000-year-old Mesolithic skeleton discovered at the La Braña-Arintero site in León, Spain, to retrieve a complete pre-agricultural European human genome. Analysis of this genome in the context of other ancient samples suggests the existence of a common ancient genomic signature across western and central Eurasia from the Upper Paleolithic to the Mesolithic. The La Braña individual carries ancestral alleles in several skin pigmentation genes, suggesting that the light skin of modern Europeans was not yet ubiquitous in Mesolithic times. Moreover, we provide evidence that a significant number of derived, putatively adaptive variants associated with pathogen resistance in modern Europeans were already present in this hunter-gatherer.

Next-generation sequencing (NGS) technologies are revolutionizing the field of ancient DNA (aDNA), and have enabled the sequencing of complete ancient genomes5, 6, such as that of Ötzi, a Neolithic human body found in the Alps1. However, very little is known of the genetic composition of earlier hunter-gatherer populations from the Mesolithic period (circa 10,000–5,000 years before present, bp; immediately preceding the Neolithic period).

The Iberian site called La Braña-Arintero was discovered in 2006 when two male skeletons (named La Braña 1 and 2) were found in a deep cave system, 1,500 m above sea level in the Cantabrian mountain range (León, Northwestern Spain) (Fig. 1a). The skeletons were dated to approximately 7,000 years bp (7,940–7,690 calibrated bp)7. Because of the cold environment and stable thermal conditions in the cave, the preservation of these specimens proved to be exceptional (Fig. 1b). We identified a tooth from La Braña 1 with high human DNA content (48.4%) and sequenced this specimen to a final effective genomic depth-of-coverage of 3.40× (Extended Data Fig. 1).

We used several tests to assess the authenticity of the genome sequence and to determine the amount of potential modern human contamination. First, we observed that sequence reads from both the mitochondrial DNA (mtDNA) and the nuclear DNA of La Braña 1 showed the typical ancient DNA misincorporation patterns that arise from degradation of DNA over time8 (Extended Data Fig. 2a, b). Second, we showed that the observed number of human DNA fragments was negatively correlated with the fragment length (R2 > 0.92), as expected for ancient degraded DNA, and that the estimated rate of DNA decay was low and in agreement with predicted values9 (Extended Data Fig. 2c, d). We then estimated the contamination rate in the mtDNA genome, assembled to a high depth-of-coverage (91×), by checking for positions differing from the mtDNA genome (haplogroup U5b2c1) that was previously retrieved with a capture method2. We obtained an upper contamination limit of 1.69% (0.75–2.6%, 95% confidence interval, CI) (Supplementary Information). Finally, to generate a direct estimate of nuclear DNA contamination, we screened for heterozygous positions (among reads with >4× coverage) in known polymorphic sites (Single Nucleotide Polymorphism Database (dbSNP) build 137) at uniquely mapped sections on the X chromosome6 (Supplementary Information). We found that the proportion of false heterozygous sites was 0.31%. Together these results suggest low levels of contamination in the La Braña 1 sequence data.


http://www.nature.com/nature/journal/v5 ... E-20140313

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Re: Nature News

Inlägg av Tryggve » ons 12 mar 2014, 20:29

En artikel om problemen för anläggningar som ska producera bränsleetanol från cellulosa. Det finns några anläggningar som står i startgroparna, men de har problem. Kostnaderna är höga, och marknaden i USA (tydligen) nästan mättad med etanol från majs.


http://www.nature.com/news/cellulosic-e ... E-20140313
Cellulosic ethanol fights for life

Pioneering biofuel producers hope that US government largesse will ease their way into a tough market.


On the flat plains of Kansas, a stack of gleaming steel towers and pipes stretches 16 storeys into the sky. More than 1,000 construction workers toiled to complete the ethanol plant near the town of Hugoton, and its owners expect it to join a fermented-fuel revolution.

But unlike most ethanol factories, in which yeast feeds on sugars in foodstuffs such as maize (corn) kernels, the Hugoton facility will make use of what has been, until now, agricultural waste: cellulose. Thousands of tonnes of corn stover — the leaves, stalks and husks left over after the maize harvest — are already waiting, stacked in square bales, at the 1.6-square-kilometre site. By June, the plant will begin processing the stover into ethanol, which will be blended with petrol and end up in vehicle fuel tanks.

The plant, which is owned by multi­national company Abengoa of Seville, Spain, is one of three US facilities that should start commercial production of cellulosic ethanol in the next few months (the others are both in Iowa, one run by POET-DSM Advanced Biofuels and the other by DuPont). The industry has long promised that this second-generation biofuel will cut greenhouse-gas emissions, reduce US reliance on imported oil and boost rural economies. Yet just as the fuel is on the cusp of making it big, market forces and government policies could choke its progress. “This is going to be a very critical year,” says Zia Haq, a chemical engineer and senior analyst at the US Department of Energy, which has helped to fund the plants. The challenges have already pushed some researchers and companies towards an alternative approach that converts cellulose into hydrocarbon fuels using chemical rather than biological processes.

With more than 200 operating plants, the corn-ethanol industry is well established in the United States. Its dramatic growth has been driven by tax credits and the Renewable Fuel Standard (RFS), created by law in 2005 and extended in 2007. Administered by the US Environmental Protection Agency (EPA), the standard mandates annual increases in the volumes of various renewable fuels included in the country’s fuel supply. In its early years, the law emphasized the production of corn ethanol, considered ripe for early commercialization.

et corn ethanol comes with problems. It offers only modest savings in greenhouse-gas emissions compared to petrol (see Nature 499, 13–14; 2013). Production is vulnerable to poor harvests and can contribute to increased food prices because the maize must be grown on land that would otherwise be used for food. Tapping the storehouse of biomass left after the harvest is much less controversial. Ethanol made from corn stover produces at least 60% less greenhouse-gas emissions than petrol, and making it does not require any extra farmland.

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Re: Nature News

Inlägg av Tryggve » tis 18 mar 2014, 16:08

Skadeinsekt som blivit resistent mot två typer av Bacillus thurinigiensis-toxin hittad i Iowa. Visar att man inte bör försumma saker som växelbruk eller.
Pests worm their way into genetically modified maize

Broadening of rootworm resistance to toxins highlights the importance of crop rotation.

Even with biotech crops, farmers still need to make use of age-old practices such as crop rotation to fight insect pests. That’s the lesson to be drawn from the latest discovery of resistance to the pest-fighting toxins added to maize — also known as corn.

According to a team led by Aaron Gassmann, an entomologist at Iowa State University in Ames, in some Iowa fields a type of beetle called the western corn rootworm (Diabrotica virgifera virgifera LeConte) has developed resistance to two of the three types of Bacillus thurinigiensis (Bt) toxin produced by genetically modified maize. Resistance to one type of Bt toxin has cropped up in the worms in recent years, but now there is a twist — the researchers have found that resistance to that type of Bt toxin also confers protection against another, more recently introduced type. Their work appears in this week's Proceedings of the National Academy of Sciences1.

Genetically modified (GM) maize producing the Bt toxin Cry3Bb1, which provided protection against pests such as rootworm, was first approved for use in the United States in 2003. By 2009, farmers had started to see rootworm damage in their GM crops. In 2011, that damage had spread to GM maize containing a second toxin, mCry3A. In lab tests, Gassmann showed that this was a case of cross-resistance — worms that had become resistant to Cry3Bb1 were also resistant to mCry3A, possibly because the toxins share structural similarities and some binding sites in the insect’s gut.

Part of the problem is that rootworms are tough, and the Bt maize does not produce enough toxin to fully control them. The Bt toxins used against pests such as the European corn borer (Ostrinia nubilalis) kill more than 99.99% of their targets, whereas more than 2% of rootworms can survive Bt maize. Resistance in the worms can evolve rapidly in fields where the same kind of maize is grown every year — in Iowa it showed up after an average of 3.6 years.

“That’s two of the three toxins on the market now,” says Gassmann. “It’s a substantial part of the available technology.”


http://www.nature.com/news/pests-worm-t ... S-20140318

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Re: Nature News

Inlägg av Hexmaster » tis 18 mar 2014, 18:25

Intressant. Har inte tänkt på att fördelarna med GMO kan minska över tid men det är ju likadant som med andra motmedel.
“That’s two of the three toxins on the market now,” says Gassmann. “It’s a substantial part of the available technology.”
Detta skall jag visa dig medelst ett stort papper som jag har fyllt med faktiska upplysningar! - Strindberg

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