A Bit More Detail

Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘science

[LINK] “Should we geoengineer larger ice caps?”

The Dragon’s Tales linked to a remarkable arXiv paper by Jacob Haqq-Misra, “Should we geoengineer large ice caps?”. The abstract is below.

The climate of Earth is susceptible to catastrophes that could threaten the longevity of human civilization. Geoengineering to reduce incoming solar radiation has been suggested as a way to mediate the warming effects of contemporary climate change, but a geoengineering program for thousands of years could also be used to enlarge the size of the polar ice caps and create a permanently cooler climate. Such a large ice cap state would make Earth less susceptible to climate threats and could allow human civilization to survive further into the future than otherwise possible. Intentionally extending Earth’s glacial coverage will require uninterrupted commitment to this program for millenia but would ultimately reach a cooler equilibrium state where geoengineering is no longer needed. Whether or not this program is ever attempted, this concept illustrates the need to identify preference among potential climate states to ensure the long-term success of civilization.

Part of this reminds me of the episodes of The Simpsons where Mr. Burns found out that he was deathly ill with any number of diseases, but that they counterbalanced each other enough to let him live.

More relevantly, these are the sorts of decisions that people managing the environments of highly engineered worlds are going to have to make. This includes our dear Earth.

Written by Randy McDonald

July 22, 2015 at 10:36 pm

[LINK] “A lake in the Northwest Territories is about to fall off a cliff”

The Globe and Mail shared Bob Weber’s Canadian Press article describing how global warming will lead to a lake in the Northwest Territories falling off a cliff.

Some time in the next few months, a small northern lake will burst through the shrinking earthen rampart holding it back and fall off a cliff.

“It’s got a ways to travel,” says Steve Kokelj of the Northwest Territories Geological Survey. “This lake happens to be perched about 600 feet above the Mackenzie Valley.”

[. . .]

The doomed lake, which has no name and sits in the northern corner of the territory near the community of Fort McPherson, is a victim of the region’s geology and changing climate.

Permafrost in this part of the N.W.T. contains a high percentage of ice in headwalls, which can be up to 30 metres thick. That ice has been there since the retreat of the Laurentide Ice Sheet 20,000 years ago.

Trouble starts when parts of the headwalls are exposed by erosion from wind or rain. The ice melts, which causes the soil and rock on top to collapse. That exposes more ice, which also melts and extends the collapse, and the cycle keeps repeating.

“It thaws in the summertime and will continue to work its way back upslope until you run out of ice or the headwall gets covered by sediment,” Kokelj says. “The slumps chew their way upslope.”

Written by Randy McDonald

July 22, 2015 at 10:30 pm

[LINK] “Black Death Left a Mark on Human Genome”

Science‘s Elizabeth Pennisi wrote about a fascinating study that, by comparing the genes of ethnic Romanians with Roma residents of that country, determined that the black death had left an imprint on European populations absent elsewhere.

The Black Death didn’t just wipe out millions of Europeans during the 14th century. It left a mark on the human genome, favoring those who carried certain immune system genes, according to a new study. Those changes may help explain why Europeans respond differently from other people to some diseases and have different susceptibilities to autoimmune disorders.

Geneticists know that human populations evolve in the face of disease. Certain versions of our genes help us fight infections better than others, and people who carry those genes tend to have more children than those who don’t. So the beneficial genetic versions persist, while other versions tend to disappear as those carrying them die. This weeding-out of all but the best genes is called positive selection. But researchers have trouble pinpointing positively selected genes in humans, as many genes vary from one individual to the next.

Enter Mihai Netea, an immunologist at Radboud University Nijmegen Medical Centre in the Netherlands. He realized that in his home country, Romania, the existence of two very distinct ethnic groups provided an opportunity to see the hand of natural selection in the human genome. A thousand years ago, the Rroma people—commonly known as gypsies—migrated into Europe from north India. But they intermarried little with European Romanians and thus have very distinct genetic backgrounds. Yet, by living in the same place, both of these groups experienced the same conditions, including the Black Plague, which did not reach northern India. So the researchers sought genes favored by natural selection by seeking similarities in the Rroma and European Romanians that are not found in North Indians.

Netea; evolutionary biologist Jaume Bertranpetit of Pompeu Fabra University in Barcelona, Spain; and their colleagues looked for differences at more than 196,000 places in the genomes of 100 Romanians of European descent and 100 Rroma. For comparison, the researchers also cataloged these differences in 500 individuals who lived in northwestern India, where the Rroma came from. Then they analyzed which genes had changed the most to see which were most favored by selection.

Genetically, the Rroma are still quite similar to the northwestern Indians, even though they have lived side by side with the Romanians for a millennium, the team found. But there were 20 genes in the Rroma and the Romanians that had changes that were not seen in the Indians’ versions of those genes, Netea and his colleagues report online today in the Proceedings of the National Academy of Sciences. These genes “were positively selected for in the Romanians and in the gypsies but not in the Indians,” Netea explains. “It’s a very strong signal.”

Written by Randy McDonald

July 21, 2015 at 10:53 pm

[CAT] “Are Cats Really Wild Animals?”

Slate‘s David Grimm reports on the debate on the extent to which cats are domesticated.

The other night, before my wife and I put our 2½-year-old twins to bed, she began reading them one of their favorite books, Where the Wild Things Are. Juliet, in Dalmatian pajamas, asked, “Mommy, where are the wild things?” My wife glanced over at our gray-and-white tabby curled up on a chair nearby. “Well,” she said, “Jasper’s a wild thing.” Juliet looked incredulous. “Jasper’s not a wild thing,” she said. “He’s a cat!”

The dispute is understandable. Though cats have lived with us for nearly 10,000 years and are the world’s most popular pet, experts disagree about whether they’re actually domestic animals. Our feline companions don’t really need us, after all: They can hunt for themselves, and they go feral without human contact. A scientific paper published last year uncovered some of the first genes responsible for domestication—all in the cat genome—yet still referred to cats as “semi-domesticated.” Other scientists vehemently disagree with that designation. “There’s no difference between a domesticated cat and a domesticated anything else,” says Greger Larson, an evolutionary biologist at the University of Oxford who has studied the domestication of pigs, dogs, and a variety of other animals. “Good luck trying to get a goat or a sheep to spend the night in your house.”

At the heart of the debate is the heart of our relationship with cats. Sure, they were gods in ancient Egypt, but ever since a paranoid pope linked them to witchcraft in the 13th century, felines have been vilified as evil, unpredictable, and untrustworthy—stereotypes that persist even in this age of the adorable Internet cat video. So the question must be asked: Are cats just like dogs but in slinkier form, eager and able to be part of the human family? Or is there something truly feral about them—something wild and unknowable that will forever keep them from blending into our tribe? Put another way, are cats with us or against us?

Even early legal scholars debated the question, as I discovered while writing Citizen Canine: Our Evolving Relationship With Cats and Dogs, which traces the journey of pets from wild animals to members of the family. In 1894, a Baltimore man was arrested for stealing his neighbor’s cat. But as the judge prepared to sentence him, Maryland’s attorney general stepped in. “A cat,” he declared, “is not legal property. … It is as much a wild animal, in a legal sense, as are its relatives—the tiger and the wild-cat.” The judge was forced to let the thief go. In the eyes of the law, a man who had stolen a cat had stolen nothing at all.

In the early 1900s, however, as cats became more popular household companions, the law changed its tune. At issue in a 1914 Maine state Supreme Court case was whether a man was legally justified in shooting his neighbor’s dog because it was chasing his cat. Under state law, the shooter pointed out, a person could kill a dog that was “worrying, wounding, or killing any domestic animal.” But did a cat fit that definition? After much deliberation, the court ruled that it did. “In no other animal has affection for the home been more strongly developed,” it decreed.

Written by Randy McDonald

July 18, 2015 at 10:39 pm

Posted in History, Science

Tagged with , , , ,

[CAT] “Cats Are City Slickers”

Live Science’s Tia Ghose reports on a study suggesting cats are less efficient predators than some have feared.

Cats have gotten a bad rap in recent years. The furry carnivores have been implicated in wildlife killings: Researchers reported in 2013 that American cats kill up to 3.7 billion birds, and more than 20 billion small mammals, each year. Most of those killings are tied to feral cats, which don’t have human owners, though kitty cams have revealed outdoor domestic cats are also partaking in the carnage, that study found.

To better understand Felis catus, Hess and his colleagues, along with hundreds of citizens in six Eastern states from Maryland to Tennessee, deployed critter cams in yards, urban parks, protected wild spaces and green corridors.

After analyzing millions of hours of footage, the team found that cats tended to stick to urban and suburban settings: They were 300 times more likely to pop up in residential yards than in parks.

In addition, cats were scarce in areas where coyotes roamed. The more coyotes that prowled an area, the fewer kitties ventured there, according to the study, which was published today (June 30) in the Journal of Mammalogy. The one exception was that coyotes were occasionally found in urban corridors that were connected to larger green spaces, said study co-author William McShea, a wildlife ecologist at the Smithsonian Conservation Biology Institute in Virginia.

[. . .]

The new findings, however, suggest coyotes play a positive role in keeping cats at bay in wilder spaces, McShea said. Coyotes are the “big kid on the block” and are aggressive toward cats, which may cause cats to stay off coyote turf, he added.

Written by Randy McDonald

July 18, 2015 at 10:37 pm

Posted in Science, Urban Note

Tagged with , , ,

[CAT] “To save big cats from extinction, scientists say we need to redefine ‘tiger’”

Marginal Revolution’s Tyler Cowen linked to Robert Gebelhoff’s Washington Post article noting arguments in favour of a new taxonomy for tigers.

Fewer than 4,000 tigers roam across the Asian continent today, compared to about 100,000 a century ago. But researchers are proposing a new way to protect the big cats: redefine them.

The proposal, published this week in Science Advances, argues current taxonomy of the species is flawed, making global conservation efforts unnecessarily difficult.

There are up to nine commonly accepted subspecies of tigers in the world, three of which are extinct. But the scientists’ analysis, conducted over a course of several years, claims there are really only two tiger subspecies: one found on continental Asia and another from the Indonesian islands of Sumatra, Java and Bali.

“It’s really hard to distinguish between tigers,” said Andreas Wilting, the study’s lead author from the Leibniz Institute for Zoo and Wildlife Research. “There has been no comprehensive approach. The taxonomies are based on data from almost a hundred years ago.”

The study, described by its authors as “the most comprehensive analysis to date,” looked at the mitochondrial DNA, skulls, skin markings, habitat and prey of all nine tiger subspecies. It found a high degree of overlap in these traits between the continental tigers — spanning from Russia to Southeast Asia — and between the island-dwelling “Sunda” tigers.

Written by Randy McDonald

July 18, 2015 at 10:35 pm

Posted in Science

Tagged with , ,

[CAT] “Did Ancient Native Americans Try to Domesticate Bobcats?”

George Dvorsky’s io9 post amused me.

The 2,000-year-old remains of a carefully decorated and deliberately buried juvenile bobcat has scientists wondering if it’s the first example of feline domestication in the prehistoric Americas.

The remains of the bobcat were originally discovered in the 1980s at the Illinois Hopewell Burial Mounds just north of St. Louis. Archaeologists had mistakenly identified the bones as belonging to a young dog and placed it in the archives of the Illinois State Museum in Springfield. Now, a new analysis by Ph.D. student Angela Perri and her team from the University of Durham in the UK, has correctly identified the bones as belonging to a bobcat (Lynx rufus) that was likely between four and seven months old when it perished. The results of their work can now be found at Midcontinental Journal of Archaeology.

Incredibly, the bobcat kitten was buried by a group of Middle Woodland Native Americans in a very human-like way, among the remains of humans and dogs. The bobcat was adorned with a necklace made from seashells, along with a bone carved to look like bear teeth (seen above). What’s more, the complete skeleton showed no signs of trauma, which suggests it wasn’t sacrificed.

Written by Randy McDonald

July 18, 2015 at 10:31 pm


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