other rss:Shared by Lo Lo Bird
I've never seen such a nice looking Koala before.
The kangaroo’s twisted marsupial family tree is now in order thanks to — you guessed it — jumping genes. Genetic evidence shows that a South American ancestor gave rise to all Australian marsupials, and that the South American opossums were the earliest group to branch off from the other six marsupial clans.
Distinctive for raising their live-born young in protective pouches, marsupials all trace back to a common ancestor that split off from the rest of the mammals about 130 million years ago. But fossil and genetic evidence conflict about which marsupial species evolved first, and where.
Jumping genes provide new clues for solving the puzzle. These “junk” bits of DNA make copies of themselves to reinsert randomly in the genome. Half of the marsupial genome consists of jumping genes, so researchers have plenty to work with. Gene-jumping is rare, and each jump is a unique event unlikely to happen again. So if two species share a jumping gene, scientists can deduce that they inherited it from a common ancestor.
Maria Nilsson and her colleagues at Westfälische Wilhelms Universität Münster in Germany looked at similarities and differences in jumping genes in the seven main branches of marsupials. In the July PLoS Biology, the team presents a new marsupial family tree with slightly different familial relationships than other research had predicted.
“It’s a different type of data, and it’s much cleaner [than fossil and genetic data],” says evolutionary biologist David Pollock of the University of Colorado School of Medicine in Denver, who was not involved with the research.
According to the new tree, all Australian marsupials arose from a single South American ancestor. In addition, their data puts the gray, short-tailed South American opossum on the earliest branch of the marsupial tree.
There’s always the potential for error in molecular studies, says mammologist Ines Horovitz of the University of California, Los Angeles. But she says the study “contributes new data, and that’s always important.”
Next, Nilsson says she wants to use jumping genes to probe the relationships among the Australian marsupials to see exactly how they’re related.
Image: Koala in Currumbin Wildlife Sanctuary, Queensland, Australia./Flickr/Erik Veland.
See Also:
A massive simulation of soot’s climate effects finds that basic pollution controls could put a brake on global warming, erasing in a decade most of the last century’s temperature change.
Compared to the larger, longer term task of getting greenhouse-gas pollution under control, limiting soot wouldn’t be hard. Unlike new energy technology and profound changes in lifestyle, the tools — exhaust filters, clean-burning stoves — already exist.
“Soot has such a strong climate effect, but it has a lifetime in the atmosphere of just a few weeks. Carbon dioxide has a lifetime of 30 to 50 years. If you totally stop CO2 emissions today, the Arctic will still be totally melted,” said Stanford University climate scientist Mark Jacobson. If soot pollution is immediately curtailed, “the reductions start to occur pretty much right away. Within months, you’ll start seeing temperature differences.”
Jacobson’s simulation, currently in press at the Journal of Geophysical Research-Atmospheres, is the latest in a line of studies showing a powerful climate role for fine soot, also known as black carbon. (That’s a somewhat misleading appellation, since some carbon is brown, and the pollution in soot contains a host of other compounds.)
Soot comes from the incomplete combustion of fossil fuels, and also from the burning of wood or dung for fuel. Crop residue and forest-burning are another major source. When aloft, the dark particles absorb sunlight, raising local temperatures and causing rain clouds to form, which in turn deprive other areas of moisture. When soot lands on snow or ice, its effects are magnified, because melts reveal fresh patches of heat-absorbing dark ground.
In 2003, a NASA simulation blamed soot for 25 percent of the past century’s observed warming. A study last year suggested that soot was responsible for almost half of a 3.4-degree Fahrenheit rise in average Arctic temperatures since 1890 — a greater rise than anywhere else on Earth.
Soot also appears to be a culprit in drastic melts of Himalayan glaciers which provide water to much of South Asia, and in disrupting the monsoon cycles on which the region’s farmers rely. The United Nations puts the soot-related death toll at 1.5 million people annually.
Jacobson’s simulation, the culmination of 20 years of research on the dynamics of soot and its interaction with local, regional and global climate dynamics, reinforces those findings. It also studies a question implicit in the earlier studies, but not yet modeled: What would happens if soot pollution stopped?
“If you just eliminate soot, you get a significant climate benefit, and you can do it on a short time period, because soot has a life of just a few weeks,” said Jacobson. “You don’t get the full response for a while, as there are deep ocean feedbacks that take a long time, but it’s a lot faster than controlling CO2.”
Jacobson simulated the effects of curtailing soot from fossil-fuel emissions, something that’s already possible with tailpipe and smokestack filters. He simulated the effects of replacing wood- and dung-burning cookfires with clean-burning stoves. And he simulated both advances simultaneously.
If soot disappeared overnight, average global temperatures would drop within 15 years by about 1 degree Fahrenheit, maybe a little more. That’s about half the net warming — total global warming, minus cooling from sun-reflecting aerosols — experienced since the beginning of the industrial age. The effect would be even larger in the Arctic, where sea ice and tundra could rapidly refreeze.
“It will take some decades to phase down fossil-fuel emissions, so reducing dirty aerosols [soot] while we are doing that may help retain Arctic sea ice,” said NASA climatologist James Hansen, one of the first researchers to study soot dynamics. But he emphasized that soot control is only a stopgap measure. “We should reduce soot for several reasons, especially its health effects, but it is only a modest help in controlling global warming,” he said.
Nevertheless, soot could ease the delay between controlling greenhouse gas emissions and cooling. It might also help “avoid tipping points — nonlinear, abrupt and potentially irreversible climate change, especially in the Arctic,” said Erika Rosenthal, a climate policy expert at the progressive nonprofit Earthjustice.
Soot-control policy, however, is scattered. According to Jacobson, climate policymakers have paid little attention to soot. Compared to well-studied greenhouse gases, its climate role is new and unfamiliar. “There are international efforts to limit greenhouse gases, but they completely ignore soot as something to control from a climate perspective,” said Jacobson.
The draft international climate treaty negotiated last year in Copenhagen doesn’t contain soot-specific provisions, but the United Nations Environmental Program is meeting in February to discuss policy options on soot. A relatively little-known U.N. effort called the Convention on Long-Range Transboundary Air Pollution has also established a black-carbon working group.
In the United States, a rare bipartisan environmental bill sponsored in 2009 by climate skeptic James Inhofe (R-Oklahoma) and environmentalist Barbara Boxer (D-California) foundered after its inclusion in massive energy legislation that recently died in Congress. It would have required the EPA to study and possibly regulate black-carbon emissions.
In anticipation of these legislative difficulties, the EPA was charged this year with launching a black-carbon study. More immediately, Congress is now debating reauthorization of the Diesel Emissions Reduction Act, a federal program that pays for putting clean tailpipes on diesel-fuel–burning automobiles, a prime source of black carbon. According to Rosenthal, the program has been fantastically successful, with retrofit requests exceeding available funds by $2 billion.
Controlling crop and forest burns isn’t so easy, but clean stoves could be provided to the developing world for relatively little money. “We have the technology now. It’s a matter of implementing it,” said Rosenthal.
“It’s low-hanging fruit,” said Jacobsen. “It’s straightforward to address, and it can be addressed.”
Images: 1) Rennett Stowe/Flickr. 2) Average global air temperature decline following elimination of fossil-fuel–based soot (dotted line) and fossil-fuel– plus biofuel–based soot (solid line).
Citation: “Short-term effects of Controlling Fossil-Fuel Soot, Biofuel Soot and Gases, and Methane on Climate, Arctic Ice, and Air Pollution Health.” By Mark Jacobson. Journal of Geophysical Research-Atmospheres, in press.
Legislators question US president's Afghan war-strategy after Wikileak disclosures.
Every age has its own poetry; in every age the circumstances of history choose a nation, a race, a class to take up the torch by creating situations that can be expressed or transcended only through poetry.
Classified as: ∅.
Thoughts: (0) | May 03 2010
Atheistic existentialism, which I represent, states that if God does not exist there is at least one being whose existence comes before its essence, a being which exists before it can be defined by any conception of it. That being is man . . .
If man, as the existentialist conceives him, is indefinable, it is because at first he is nothing . . .
Man is nothing else but what he makes of himself . . . man is responsible for what he is.
. . .when we say that a man is responsible for himself, we do not only mean that he is responsible for his own individuality, but that he is responsible for all men. . . I am responsible for myself and for everyone else. I am creating an image of man of my own choosing. . .
The man who involves himself and realizes that he is not only the person he chooses to be, but also a lawmaker who is, at the same time, choosing all mankind as well as himself, cannot escape the feeling of his total and deep responsibility. . .
For every man, everything happens as if all mankind had its eyes fixed on him and were guiding itself by what he does. . .
When a military leader takes upon himself the responsibility for an attack and sends a number of men to their death, he chooses to do it and at bottom he alone chooses. No doubt under a higher command, but its orders, which are more general, require interpretation by him and upon that interpretation depends the life of ten, fourteen or twenty men. In making the decision, he cannot but feel a certain anguish. All leaders know that anguish. It does not prevent their acting, on the contrary it is the very condition of their action, for the action presupposes that there is a plurality of possibilities, and in choosing one of these, they realize that it has value only because it is chosen. Now it is anguish of that kind which existentialism describes, and moreover, as we shall see, makes explicit through direct responsibility towards other men who are concerned. It is not a curtain separating us from action, but is part of action itself.
When we speak of “forlornness” – a term Heidegger was fond of – we mean only that God does not exist and that we have to face all of the consequences of this. The existentialist is strongly opposed to a certain kind of secular ethics which would like to abolish God at the least possible expense . . .
The existentialist, on the contrary, thinks it very distressing that God does not exist, because all possibility of finding values in a heaven disappears along with Him; there can no longer be an a priori Good, since there is no infinite and perfect consciousness to think it. . . Indeed, everything is permissible if God does not exist, and as a result man is forlorn, because neither within him nor without does he find anything to cling to. . .
There is no determinism, man is free, man is freedom. . .
man is condemned to be free. . .
man, with no support and no aid, is condemned at every moment to invent man. . .
The moment the possibilities I am considering are not rigorously involved by my action, I ought to disengage myself from them, because no God, no scheme, can adapt the world and its possibilities to my will. . .
Quietism is the attitude of people who say, “let others do what I can’t do.” The doctrine I am presenting is the very opposite of quietism, since it declares, “There is no reality except in action.” Moreover, it goes further, since it adds, “Man is nothing else than his plan; he exists only to the extent that he fulfills himself; he is therefore nothing else than the ensemble of his acts, nothing else than his life.” . . .
The existentialist will never consider man as an end because he is always in the making. . .
There is no universe other than a human universe, the universe of human subjectivity. . .
That man is not closed in on himself but is always present in a human universe, is what we call “Existentialist humanism.” Humanism, because we remind man that there is no lawmaker other than himself, and that in his forlornness he will decide by himself.
Classified as: Israel / Palestine, politicalness, theory.
Thoughts: (0) | May 03 2010
This video is based on a video I made in the 7th grade with my VCR, that a friend accidently recorded over (Lauren Faith!). But here it is again! Way easier to make with a computer!
Classified as: ∅.
Thoughts: (0) | Apr 19 2010
when I was an undergrad.
It was for an aesthetics class. My teacher didn’t like it.
Classified as: ∅.
Thoughts: (0) | Apr 03 2010
Please suggest a caption for this image. Nothing dirty.
Classified as: ∅.
Thoughts: (5) | Jan 05 2010
