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Posts Tagged ‘science

[LINK] “The Little Bit of Neanderthal in All of Us”

Carl Zimmer’s New York Times article summarizing two recent studies on the degree and nature of Neanderthal ancestry in modern human beings is interesting, as much for its suggestions as to what Neanderthals did contribute as to what they didn’t. They may have been more genetically distinctive than a mere isolated hominid population.

The first draft of the Neanderthal genome was too rough to allow scientists to draw further conclusions. But recently, researchers sequenced a far more accurate genome from a Neanderthal toe bone.

Scientists at Harvard Medical School and the Max Planck Institute for Evolutionary Anthropology in Germany compared this high-quality Neanderthal genome to the genomes of 1,004 living people. They were able to identify specific segments of Neanderthal DNA from each person’s genome.

“It’s a personal map of Neanderthal ancestry,” said David Reich of Harvard Medical School, who led the research team. He and his colleagues published their results in the journal Nature.

Living humans do not have a lot of Neanderthal DNA, Dr. Reich and his colleagues found, but some Neanderthal genes have become very common. That’s because, with natural selection, useful genes survive as species evolve. “What this proves is that these genes were helpful for non-Africans in adapting to the environment,” Dr. Reich said.

[. . .]

Both studies suggest that Neanderthal genes involved in skin and hair were favored by natural selection in humans. Today, they are very common in living non-Africans.

[. . .]

Both teams of scientists also found long stretches of the living human genomes where Neanderthal DNA was glaringly absent. This pattern could be produced if modern humans with certain Neanderthal genes could not have as many children on average as people without them. For example, living humans have very few genes from Neanderthals involved in making sperm. That suggests that male human-Neanderthal hybrids might have had lower fertility or were even sterile.

Overall, said Dr. Reich, “most of the Neanderthal genetic material was more bad than good.”

io9/u> and National Geographic go also have posts discussing the findings.

Written by Randy McDonald

January 30, 2014 at 2:17 am

[BLOG] Some Saturday links

  • blogTO reviews Weird Things, a new gallery of oddities on Bathurst above Bloor, and shares the good news that games cafe Snakes & Lattes is opening a game bar on College called Snakes & Lagers.
  • Centauri Dreams anticipates the discoveries coming from Ceres and Pluto when their destined space probes arrive in a couple of years.
  • Joe. My. God. notes that American congressman Aaron Schock, known for his anti-gay politics as well as certain things hinting at being in the closet, has made his Instagram account private after being outed.
  • Language Log tracks the meaning and usage of the term “86″.
  • Marginal Revolution notes a recent study in legal pluralism in the Ottoman Empire (different religious minorities adopted different civil codes for commercial and other reasons, why?) and finds the largest shadow economies in the different states of the US.
  • Torontoist’s David Wencer looks at Toronto’s first gangland killing, that of bookie Jimmie Windsor in 1939.
  • Towleroad touches upon the struggles of intersex children regarding their right to determine their gender and their genitalia at their own pace, and notes that Navajo are fighting for marriage equality in their large reserve.
  • Transit Toronto notes that a water pipe breakage at Yonge and Bloor has flooded the subway station and brought chaos to the TTC.
  • The Volokh Conspiracy’s Stewart Baker links to and comments upon a New Yorker article examining the slow but real communications and intelligences of plants, and what they might mean for our own technological future.

[BLOG] Some Friday links (1)

  • Centauri Dreams’ Paul Gilster describes, after Timothy Ferris and Greg Egan, the idea of a “galactic Internet” that we just have to find a way to plug into.
  • Will Baird at The Dragon’s Tales describes one theory for identifying life-supporting worlds on super-Earths orbiting red dwarfs from their spectrographic signatures, and another suggesting that gravitational resonances from Jupiter and Saturn prevented the formation of more, and more massive, planets in the area of Mars.
  • Daniel Drezner notes that austerity is controversial in Poland.
  • Eastern Approaches touches upon illegal–that is to say, unregulated–adoption in Poland.
  • Language Log considers the phonemic–vowel-like, even–qualities of the “Mc” in McDonald’s. I’m amused.
  • The Power and the Money’s Noel Maurer notes that the United States is no longer supporting Argentina’s international legal issues with the foreigners claiming its debt.
  • Is Towleroad essayist RJ Aguiar correct in claiming that the gay rights movement has neglected sexual freedom for more conservative marriage-type issues?
  • A couple of posts at the Volokh Conspiracy suggest that the fall of Detroit can be connected to the use of eminent domain to confiscate property for development. (I suspect causality is reversed.)
  • Window on Eurasia points to some interesting articles: one claims that Ukraine for all of its issues is more pluralistic and thus more hopeful than Russia; another talking about the unlikelihood that South Ossetia, once Georgian, will be reunited with North Ossetia inside Russia; and, a final one suggesting that anti-GLBT attitudes are rife throughout the South Caucasus.

[BLOG] Some Thursday links

  • Centauri Dreams notes the thinking of Martin Rees and Freeman Dyson on the diaspora of life beyond Earth, noting that it’s going to require as much adaptation to new environments as it will (would?) the adaptation of existing environments.
  • D-Brief notes theory about planetary system formation suggesting that suggestive gaps in protoplanetary discs of gas and dust don’t necessarily reveal planets.
  • The Dragon’s Tales’ Will Baird links to the recent paper suggesting that tide-locked red dwarf planets are much more likely to be habitable than previously thought.
  • Geocurrents analyses the possibility that Iran might be divided between a conservative Persian-speaking core and reformist peripheries.
  • GNXP’s Razib Khan notes evidence from Ethiopia suggesting that there has been immigration into Africa as well out of the continent.
  • Registan describes a Chinese copper mining project in Afghanistan that never quire took off.
  • Savage Minds’ Rex reviews William McNeill’s biography of historian Arnold J. Toynbee.
  • Strange Maps maps the leading causes of death by continent.
  • Supernova Condensate describes the possibility of life-supporting environments on Europa, not only in the subsurface ocean but in lakes located in the ice crust.
  • Window on Eurasia quotes a Tatar nationalist who argues that Tatarstan can be to Russia what Lithuania was to the former Soviet Union, i.e. the unit which breaks the country apart.

[BLOG] Some Tuesday links (2)

  • Bad Astronomy’s Phil Plait approves of the names of Pluto’s two most recently-discovered moons, Kereberos and Styx.
  • Beyond the Beyond’s Bruce Sterling observes that Altavista is set to disappear from the Internet as of the 8th.
  • Daniel Drezner notes that the inability of Edward Snowden to find a country to grant him, buster of state secrets, asylum demonstrates that states around the world like keeping their prerogatives and secrets intact.
  • Commemorating the accession of Croatia to the European Union, Eastern Approaches visits a Dubrovnik that is virtually an enclave on account of the Bosnian frontier, and, at the other end of the Croatian arc, a Vukovar still caught up by ethnic conflict and the legacies of the Serb war in Slavonia.
  • Far Outliers notes the decline of immigrant Japanese Buddhism in Hawaii.
  • The Power and the Money’s Noel Maurer explains why Uruguay, contrary to the wishes of many Argentines including–apparently–the president, is a country separate from Argentina.
  • Registan approves of alumnus Sarah Kendzior’s examination of the plight of Uzbek migrants, stigmatized by the Karimov dictatorship as lazy for trying to earn a living and forced to witness the victimization of their relatives if they do anything wrong.
  • Savage Minds quotes from Umberto Eco’s definition of fascism.
  • The Tin Man celebrates, as a coupled American gay man, the end of DOMA.
  • Torontoist reports that much of the controversy over the Walmart on the fringes of Kensington Market might be–according to the designer–a consequence of a lack of understanding of the design.
  • Van Waffle reports on highlights of his 2012 breeding bird survey.
  • Yorkshire Ranter Alex Harrowell reports on David Goodhart’s still-dodgy use of statistics.

[LINK] “Mars had oxygen-rich atmosphere 4,000 million years ago”

The Dragon’s Tales linked to a remarkable press release claiming, based on an analysis of rocks surveyed by the Spirit rover, that four billion years ago Mars had an oxygen-rich atmosphere.

Differences between Martian meteorites and rocks examined by a NASA rover can be explained if Mars had an oxygen-rich atmosphere 4000 million years ago – well before the rise of atmospheric oxygen on Earth 2500m years ago.

Scientists from Oxford University investigated the compositions of Martian meteorites found on Earth and data from NASA’s ‘Spirit’ rover that examined surface rocks in the Gusev crater on Mars. The fact that the surface rocks are five times richer in nickel than the meteorites was puzzling and had cast doubt on whether the meteorites are typical volcanic products of the red planet.

‘What we have shown is that both meteorites and surface volcanic rocks are consistent with similar origins in the deep interior of Mars but that the surface rocks come from a more oxygen-rich environment, probably caused by recycling of oxygen-rich materials into the interior,’ said Professor Bernard Wood, of Oxford University’s Department of Earth Sciences, who led the research reported in this week’s Nature.

‘This result is surprising because while the meteorites are geologically ‘young’, around 180 million to 1400 million years old, the Spirit rover was analysing a very old part of Mars, more than 3700 million years old.’

Whilst it is possible that the geological composition of Mars varies immensely from region to region the researchers believe that it is more likely that the differences arise through a process known as subduction – in which material is recycled into the interior. They suggest that the Martian surface was oxidised very early in the history of the planet and that, through subduction, this oxygen-rich material was drawn into the shallow interior and recycled back to the surface during eruptions 4000 million years ago. The meteorites, by contrast, are much younger volcanic rocks that emerged from deeper within the planet and so were less influenced by this process.

Professor Wood said: ‘The implication is that Mars had an oxygen-rich atmosphere at a time, about 4000 million years ago, well before the rise of atmospheric oxygen on earth around 2500 million years ago. As oxidation is what gives Mars its distinctive colour it is likely that the ‘red planet’ was wet, warm and rusty billions of years before Earth’s atmosphere became oxygen rich.’

The unspoken implication of an oxygen-rich atmosphere four billion years ago on Mars is that the atmosphere was substantially modified by life, just as the Earth’s atmosphere has been, hence that Mars was host to abundant life. It’s not altogether clear to me, though, what proportion of oxygen counts as “rich” in the context of the formation of rocks. One commenter at the Guardian thinks that there exist alternate explanations for the formation of these rocks in processes in the rocky mantle of Mars.

Written by Randy McDonald

June 20, 2013 at 3:10 am

[LINK] “Fish farming tops beef production in race to the plate”

Aquaculture isn’t of the future, the CBC notes; it’s an increasingly dominant reality.

The human diet appears to have reached an important milestone, as worldwide fish farm production has surpassed beef production for the first time in the modern era.

[. . .]

The UN’s Food and Agriculture Organization estimates that fish farm production has grown by six times over the last 20 years.

[. . .]

Everything from fish to seaweed and shellfish is farmed today. And not surprisingly, China leads the world in aquaculture.

“I think farmed fish will be part of the answer in terms of food supply,” said Janet Larsen, research director with the Earth Policy Institute in the U.S.

Aquaculture is the least energy-intensive means of producing animal protein, but not all fish farms are created equal, says Larsen.

Some threaten ecologically-sensitive areas while farming certain species, such as salmon, causes a drain on wild fish.

“We’re overfishing a lot of our smaller fish stocks like menhaden, herring or sardines so that we could grind them up into fish meal and fish oil to feed to these farmed fish,” she said.

Larsen predicts that, for the first time, more fish and seafood will be produced on farms this year than caught in the wild, meaning the need for sustainable aquaculture is greater than ever.

The website of the Food and Agriculture Organization has more.

Written by Randy McDonald

June 14, 2013 at 7:50 pm

[LINK] “Cloaking Device Makes a Cat Disappear”

Wired Science’s Nadia Drake writes about a new cloaking device.

Scientists in Singapore and China have crafted a cloaking device that works in natural light, and they’ve recorded videos of animals disappearing inside it. You wouldn’t want to wear it, though. The cloak is made from thin sheets of glass, and it doesn’t work from all angles.

This new device, described June 7 in a manuscript uploaded to arXiv.org, works by redirecting light waves around objects inside it. But unlike other recently described cloaking devices built from metamaterials — artificial materials with properties not found in nature — it’s made from a type of ordinary glass that bends and disperses light. Scientists reasoned that since human eyes cannot perceive light phase or polarization, it should be possible to achieve a cloaking effect without needing to keep redirected light waves in phase, which has been a challenge for other forms of cloaking.

Instead, ordinary materials arranged in clever ways should do the trick.

First, the team placed six thin pieces of glass inside a hollow, transparent hexagonal chamber. The result is a device with six-fold radial symmetry that will cloak an object from six different directions. To demonstrate its effectiveness, the team submerged the cloak in an aquarium — and watched as a goldfish disappeared as it swam through it while plants in the background remained visible.

Next, the team built a larger version of the device that could hide a cat. Unlike the hexagonal device, this cloak only shields an object from viewers directly in front of or behind it, as evidenced by bits of the curious cat disappearing while inside. Like the fish experiment, the cloak didn’t obscure the background, which in this case was a flowery scene projected onto the wall.

The cloak isn’t ready for prime time yet. In both environments — terrestrial and aquatic — the device itself is still partially visible, owing to the shadows it casts on the projected background and the bits of glue joining the glass with the container.

There are videos at the article.

Written by Randy McDonald

June 11, 2013 at 6:55 pm

Posted in Science

Tagged with , , ,

[BLOG] Some Sunday links

  • Acts of Minor Treason’s Andrew Barton shares a photograph of a San Francisco streetcar
  • Eastern Approaches describes how the Serbian ambassador to Turkey was cut off by the protests.
  • Geocurrents’ Asya Pereltsvaig traces the etymology of book in different world languages.
  • GNXP’s Razib Khan notes that imagined far futures where humans are recognizably the same despite huge changes otherwise, or where the only changes are superficial or ridiculous, are lacking.
  • Marginal Revolution discusses the question of whether the city of Detroit should sell off the works in its collection, leaning towards the sale.
  • Progressive Download’s John Farrell notes that scientists may have found pluripotent adult stem cells.
  • Steve Munro finds it ludicrous the extent to which Metrolinx has exaggerated the job benefits of mass transit system construction.
  • Torontoist examines the birth of the Toronto neighbourhood (once municipality) of Leaside as a planned suburb.
  • Van Waffle takes his readers on a garden tour of Toronto, with photographs.
  • Window on Eurasia notes how Karelians, facing assimilation in their Russian republic, are looking towards Finland for help.

[LINK] “New Physics Complications Lend Support to Multiverse Hypothesis”

This Scientific American article, by Natalie Wolchover and Simons Science News, makes the interesting case that the universe is just one of a near-infinitude, that our particular universe with its laws and contants is the product of not of inevitable things but of chance events. We’re just lucky enough to be living in one that supports our kind of life. (Others, committed to religious explanations of one type or another, might argue this is proof of some agency’s planning.)

With the discovery of only one particle, the LHC experiments deepened a profound problem in physics that had been brewing for decades. Modern equations seem to capture reality with breathtaking accuracy, correctly predicting the values of many constants of nature and the existence of particles like the Higgs. Yet a few constants — including the mass of the Higgs boson — are exponentially different from what these trusted laws indicate they should be, in ways that would rule out any chance of life, unless the universe is shaped by inexplicable fine-tunings and cancellations.

In peril is the notion of “naturalness,” Albert Einstein’s dream that the laws of nature are sublimely beautiful, inevitable and self-contained. Without it, physicists face the harsh prospect that those laws are just an arbitrary, messy outcome of random fluctuations in the fabric of space and time.

The LHC will resume smashing protons in 2015 in a last-ditch search for answers. But in papers, talks and interviews, Arkani-Hamed and many other top physicists are already confronting the possibility that the universe might be unnatural. (There is wide disagreement, however, about what it would take to prove it.)

“Ten or 20 years ago, I was a firm believer in naturalness,” said Nathan Seiberg, a theoretical physicist at the Institute, where Einstein taught from 1933 until his death in 1955. “Now I’m not so sure. My hope is there’s still something we haven’t thought about, some other mechanism that would explain all these things. But I don’t see what it could be.”

Physicists reason that if the universe is unnatural, with extremely unlikely fundamental constants that make life possible, then an enormous number of universes must exist for our improbable case to have been realized. Otherwise, why should we be so lucky? Unnaturalness would give a huge lift to the multiverse hypothesis, which holds that our universe is one bubble in an infinite and inaccessible foam. According to a popular but polarizing framework called string theory, the number of possible types of universes that can bubble up in a multiverse is around 10^500. In a few of them, chance cancellations would produce the strange constants we observe.

Written by Randy McDonald

June 4, 2013 at 1:15 am

Posted in Science

Tagged with , , , ,

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