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[LINK] On the possible extensive water oceans of early Mars

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The New York Times‘ Marc Kaufman reported on the controversial new suggestion, described in the new Science paper “Strong water isotopic anomalies in the martian atmosphere: Probing current and ancient reservoirs”.

After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean.

It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet’s northern hemisphere for millions of years, they said.

If confirmed, the findings would add significantly to scientists’ understanding of the planet’s history and lend new weight to the view that ancient Mars had everything needed for life to emerge.

“The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe,” said Michael Mumma, principal investigator at NASA’s Goddard Center for Astrobiology and an author of the report, published in the journal Science. “Our results tell us there had to be a northern ocean.”

But other experts said the question was hardly resolved. The ocean remains “a hypothesis,” said Ashwin Vasavada, project scientist of the Curiosity rover mission at the Jet Propulsion Laboratory in Pasadena, Calif.

The Guardian‘s Ian Sample explained the scientists’ methodology.

The scientists used the Keck II telescope and Nasa’s Infrared Telescope Facility, both in Hawaii, and the ESO’s Very Large Telescope in Chile, to make maps of the Martian atmosphere over six years. They looked specifically at how different forms of water molecules in the Martian air varied from place to place over the changing seasons.

Martian water, like that on Earth, contains standard water molecules, made from two hydrogen atoms and one oxygen atom, and another form of water made with a heavy isotope of hydrogen called deuterium. On Mars, water containing normal hydrogen is lost to space over time, but the heavier form is left behind.

When normal water is lost on Mars, the concentration of deuterium in water left behind goes up. The process can be used to infer how much water there used to be on the planet. The higher the concentration of deuterium, the more water has been lost.

The infrared maps show that water near the Martian ice caps is enriched with deuterium. The high concentration means that Mars must have lost a vast amount of water in the past, equivalent to more than six times that now locked up in the planet’s frozen ice caps.

The scientists calculate that the amount of water was enough to create a global ocean that covered the entire surface of Mars to a depth of 137m. But Mars was probably never completely submerged. Based on the Martian terrain today, the scientists believe the water pooled into a much deeper ocean in the low-lying northern plains, creating an ocean that covered nearly a fifth of the planet’s surface. The Atlantic, by comparison, covers about 17% of Earth’s surface.

“Ultimately we can conclude this idea of an ocean covering 20% of the planet which opens the idea of habitability and the evolution of life on the planet,” said Geronimo Villanueva, the first author on the study.

The Vastitas Borealis, the deep and level northern-hemispheric plain, has long been thought of as a possible ancient ocean bed.

The science can be challenged on multiple grounds. For example, are scientists correct in their judgement of Mars’ ancient hydrogen/deuterium ratios? It could go either way if they are wrong. Regardless, this has implications for ancient–and even current?–life on the Red Planet.

Written by Randy McDonald

March 5, 2015 at 11:17 pm

[LINK] “Real Paleo Diet: Early Hominids Ate Just About Everything”

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At IFL Science, Ken Sayers notes that, far from cleaving to the paleo diet in vogue now, early hominids have a diverse omnivorous diet.

Reconstructions of human evolution are prone to simple, overly-tidy scenarios. Our ancestors, for example, stood on two legs to look over tall grass, or began to speak because, well, they finally had something to say. Like much of our understanding of early hominid behavior, the imagined diet of our ancestors has also been over-simplified.

Take the trendy Paleo Diet which draws inspiration from how people lived during the Paleolithic or Stone Age that ran from roughly 2.6 million to 10,000 years ago. It encourages practitioners to give up the fruits of modern culinary progress – such as dairy, agricultural products and processed foods – and start living a pseudo-hunter-gatherer lifestyle, something like Lon Chaney Jr. in the film One Million BC. Adherents recommend a very specific “ancestral” menu, replete with certain percentages of energy from carbohydrates, proteins and fats, and suggested levels of physical activity. These prescriptions are drawn mainly from observations of modern humans who live at least a partial hunter-gatherer existence.

But from a scientific standpoint, these kinds of simple characterizations of our ancestors’ behavior generally don’t add up. Recently, fellow anthropologist C. Owen Lovejoy and I took a close look at this crucial question in human behavioral evolution: the origins of hominid diet. We focused on the earliest phase of hominid evolution from roughly 6 to 1.6 million years ago, both before and after the first use of modified stone tools. This time frame includes, in order of appearance, the hominids Ardipithecus and Australopithecus, and the earliest members of our own genus, the comparatively brainy Homo. None of these were modern humans, which appeared much later, but rather our distant forerunners.

We examined the fossil, chemical and archaeological evidence, and also closely considered the foraging behavior of living animals. Why is this crucial? Observing animals in nature for even an hour will provide a ready answer: almost all of what an organism does on a daily basis is simply related to staying alive; that includes activities such as feeding, avoiding predators and setting itself up to reproduce. That’s the evolutionary way.

[. . .]

Researchers Tom Hatley and John Kappelman noted in 1980 that hominids have bunodont – low, with rounded cusps – back teeth that show much in common with bears and pigs. If you’ve watched these animals forage, you know they’ll eat just about anything: tubers, fruits, leafy materials and twigs, invertebrates, honey and vertebrate animals, whether scavenged or hunted. The percentage contribution of each food type to the diet will depend (you guessed it) on the energetic value of specific foods in specific habitats, at specific times of year. Evidence from the entirety of human evolution suggests that our ancestors, and even we as modern humans, are just as omnivorous.

Written by Randy McDonald

March 2, 2015 at 10:18 pm

[LINK] “Most HIV Infections Come From Undiagnosed or Untreated People: Study”

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U.S. News and World Report is one news source of many sharing news of a recent study suggesting that the overwhelming majority of HIV transissions in the United States–nearly 92%–are a consequence of untreated people passing the virus on.

If an American becomes infected with HIV, chances are he or she contracted the virus from someone who didn’t know they were infected or wasn’t getting proper treatment.

That’s the message of a new U.S. study, which found that undiagnosed and untreated people with HIV may be responsible for more than nine out of 10 new infections.

The findings “highlight the community-wide prevention benefits of expanding HIV diagnosis and treatment in the United States,” a team led by Dr. Jacek Skarbinski, of the U.S. Centers for Disease Control and Prevention, wrote in the report.

Looking at 2009 data, Skarbinski’s team said that about 45,000 new cases of HIV were transmitted that year, adding to the total of more than 1.1 million Americans who were already living with HIV, the virus that causes AIDS.

Using national databases, the investigators estimated that more than 18 percent of that total remained undiagnosed, while another 45 percent were aware of their status but were not getting medical care.

Only about one-quarter of HIV-infected Americans had managed to get their viral status under control by using the current standard of care known as antiretroviral therapy, the researchers found. These drugs can lower an HIV patient’s viral load to undetectable levels.

Science Daily goes into greater detail and links to the study.

Written by Randy McDonald

February 25, 2015 at 11:31 pm

Posted in Science

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[BLOG] Some Tuesday links

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  • blogTO notes that loads of new streetcars should arrive this year for the TTC.
  • The Dragon’s Gaze links to one paper examining the impact of colliding stellar winds in a close binary on habitable planets, links to another examining how habitable planets gets their water, and wonders about the insights provided by the HR 8799 planetary system into water delivery.
  • The Dragon’s Tales links to a paper arguing that Enceladus’ subsurface ocean is made of alkaline soda water.
  • Joe. My. God. notes a claim by some British scientists that it may be possible, with foreseeable genetic engineering, to create children with two same-sex parents.
  • Languages of the World’s Asya Perelstvaig looks into what Broca’s area of the brain actually means for human language.
  • Marginal Revolution notes that the woman-dominated area of health care is a growth area for middle-class employment in the United States.
  • Otto Pohl notes that yesterday was the 71st anniversary of the deportation of the Chechens and the Ingush.
  • pollotenchegg maps industrial production in Ukraine.
  • Will Baird argues at The Power and the Money that the Minsk Accord is crumbling and examines the reasons for Chinese support of Russia.
  • Spacing Toronto’s John Lorinc worries about corporate sponsorship of ice rinks.
  • Torontoist notes that Massey Hall has begun its renovations.
  • Towleroad notes a Texan legislator who wants to make it illegal for trans people to use public washrooms.
  • Transit Toronto observes that the Union-Pearson Express is undergoing test runs.
  • Window on Eurasia worries about the potential for a minority of Russians in Latvia’s eastern Latgale province to start trouble.

[LINK] “Who Speaks for Earth? The Controversy over Interstellar Messaging”

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Universe Today’s Paul Patton notes the ongoing controversy over the idea of transmitting messages across interstellar distances, with the aim of communicating with extraterrestrial civilizations. I’m inclined to think the idea potentially existentially foolish, myself.

Should we beam messages into deep space, announcing our presence to any extraterrestrial civilizations that might be out there? Or, should we just listen? Since the beginnings of the modern Search for Extraterrestrial Intelligence (SETI), radio astronomers have, for the most part, followed the listening strategy.

In 1999, that consensus was shattered. Without consulting with other members of the community of scientists involved in SETI, a team of radio astronomers at the Evpatoria Radar Telescope in Crimea, led by Alexander Zaitsev, beamed an interstellar message called ‘Cosmic Call’ to four nearby sun-like stars. The project was funded by an American company called Team Encounter and used proceeds obtained by allowing members of the general public to submit text and images for the message in exchange for a fee.

Similar additional transmissions were made from Evpatoria in 2001, 2003, and 2008. In all, transmissions were sent towards twenty stars within less than 100 light years of the sun. The new strategy was called Messaging to Extraterrestrial Intelligence (METI). Although Zaitsev was not the first to transmit an interstellar message, he and his associates where the first to systematically broadcast to nearby stars. The 70 meter radar telescope at Evpatoria is the second largest radar telescope in the world.

In the wake of the Evpatoria transmissions a number of smaller former NASA tracking and research stations collected revenue by making METI transmissions as commercially funded publicity stunts. These included a transmission in the fictional Klingon language from Star Trek to promote the premier of an opera, a Dorito’s commercial, and the entirety of the 2008 remake of the classic science fiction movie “The Day the Earth Stood Still”. The specifications of these commercial signals have not been made public, but they were most likely much too faint to be detectable at interstellar distances with instruments comparable to those possessed by humans.

Zaitsev’s actions stirred divisive controversy among the community of scientists and scholars concerned with the field. The two sides of the debate faced off in a recent special issue of the Journal of the British Interplanetary Society, resulting from a live debate sponsored in 2010 by the Royal Society at Buckinghamshire, north of London, England.

Written by Randy McDonald

February 24, 2015 at 12:00 am

[BLOG] Some Friday links

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  • io9 notes that kale, cauliflower, and collards all are product of the same species.
  • The Dragon’s Gaze speculates on the detection of Earth analogues late in their lifespan and notes the failure to discover a predicted circumbinary brown dwarf at V471 Tauri.
  • The Dragon’s Tales shares Lockheed’s suggestion that it is on the verge of developing a 300-kilowatt laser weapon.
  • Far Outliers considers the question of who is to blame for the Khmer Rouge.
  • Joe. My. God. notes that One Million Moms is hostile to the free WiFi of McDonald’s.
  • Spacing Toronto notes an 1855 circus riot sparked by a visit of clowns to the wrong brothel.
  • Torontoist notes how demographic changes in different Toronto neighbourhoods means some schools are closing while others are straining.
  • The Volokh Conspiracy notes a California court ruling not recognizing the competence of the Iranian judicial system in a civil case on the grounds of its discrimination against religious minorities and women.
  • Window on Eurasia considers the implications of peacekeepers in eastern Ukraine, notes the steady integration of Abkhazia and South Ossetia into Russia, and notes Russian fascism.

[LINK] “Scientists announce anti-HIV agent so powerful it can work in a vaccine”

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Science Daily shares the good news.

When HIV infects a cell, it targets the CD4 lymphocyte, an integral part of the body’s immune system. HIV fuses with the cell and inserts its own genetic material — in this case, single-stranded RNA — and transforms the host cell into a HIV manufacturing site.

The new study builds on previous discoveries by the Farzan laboratory, which show that a co-receptor called CCR5 contains unusual modifications in its critical HIV-binding region, and that proteins based on this region can be used to prevent infection.

With this knowledge, Farzan and his team developed the new drug candidate so that it binds to two sites on the surface of the virus simultaneously, preventing entry of HIV into the host cell.

“When antibodies try to mimic the receptor, they touch a lot of other parts of the viral envelope that HIV can change with ease,” said TSRI Research Associate Matthew Gardner, the first author of the study with Lisa M. Kattenhorn of Harvard Medical School. “We’ve developed a direct mimic of the receptors without providing many avenues that the virus can use to escape, so we catch every virus thus far.”

The team also leveraged preexisting technology in designing a delivery vehicle — an engineered adeno-associated virus, a small, relatively innocuous virus that causes no disease. Once injected into muscle tissue, like HIV itself, the vehicle turns those cells into “factories” that could produce enough of the new protective protein to last for years, perhaps decades, Farzan said.

Written by Randy McDonald

February 19, 2015 at 10:42 pm

Posted in Science

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