purposeforporpoise

The ocean wasn't enough to hold back the daring seafarers who settled the islands of East Polynesia beginning around 4,000 years ago.  http://louis7j7sheehan.blogspot.com  A new analysis of stone tools underscores the nautical skill of ancient Polynesian mariners. It indicates that, about 1,000 years ago and prior to European contact, these intrepid canoeists transported rocks for toolmaking from Hawaii to islands more than 4,000 kilometers to the south.

Legends recounted by Polynesian islanders refer to ancestors in the distant past who used canoes with sails to travel south from the Hawaiian Islands to Tahiti and then east to the Tuamotu Islands. Chemical studies of stone tools previously recovered in the Tuamotu Islands back up those local accounts, say geologist Kenneth D. Collerson and archaeologist Marshall I. Weisler of the University of Queensland in St. Lucia, Australia.

The Tuamotus and the nearby Society Islands "could be approached from all quarters and were thus probably important in Polynesian trade," Collerson and Weisler conclude in the Sept. 28 Science.

The scientists assayed a variety of trace elements and isotopes in 19 basalt adzes-woodcutting implements resembling hoes, with stone blades fastened to the ends of wooden shafts. The late Polynesian archaeologist Kenneth Emory found the artifacts on nine coral atolls in the Tuamotus between 1929 and 1934.

Collerson and Weisler also characterized 28 volcanic-rock sources throughout Polynesia by their trace elements and isotopic compositions.

Comparisons of the Tuamotu adzes with these rocks showed that all but one came from surrounding island groups, such as the Marquesas, Pitcairn, Austral, and Society Islands.

The chemical signature of the final adze places its origin in Hawaii. The likely sea route between Hawaii and Tahiti, one of the Society Islands, via the Tuamotus has favorable winds and currents for round-trip sea voyages, the researchers say.  http://louis7j7sheehan.blogspot.com

Archaeologist Ben Finney of the University of Hawaii in Honolulu agrees. In 1976, he demonstrated that people could have settled Polynesia by navigating canoes across thousands of kilometers of open sea. He and his colleagues built a 19-meter-long reconstruction of an early two-masted Polynesian voyaging canoe. Taking roughly 2 months, they sailed the craft from Hawaii to Tahiti and back, passing through the Tuamotus along the way.

Ancient canoe voyagers must have passed their knowledge from one generation to the next until around 550 years ago, when most open-sea journeys ceased in East Polynesia, the Australian researchers suggest.  http://louis7j7sheehan.blogspot.com

The new findings follow a report that Polynesian seafarers reached what's now Chile by about 620 years ago (SN: 6/9/07, p. 356). A bone from a Chilean archaeological site contains an exact copy of a genetic sequence that appears in DNA from 600- to 2,000-year-old chicken bones found in Tonga and American Samoa.

That evidence "provided archaeological support for Polynesians having reached South America in pre-Columbian times," Finney says. "Now we need to look for Polynesian basalt adzes there."

It is hard to avoid the female sex hormone estrogen and all the chemicals that mimic it: Not only do they show up in cosmetics and cleaning products, but they are also commonly used to make plastic bottles and line food cans.  http://louisijisheehan.blogspot.com  Some experts have traced estrogen-like chemicals to increased rates of human breast cancer, and there is even more evidence that they endanger animals by feminizing the sex organs of male frogs and fish living downstream from sewage treatment plants. Then there is one species of bird—the starling—in which environmental estrogens have an especially surprising effect: Exposed male starlings turn into better singers, duping female starlings into choosing mates that may be bad bets.

The discovery comes from Cardiff University in Wales, where researchers compared starlings raised in aviaries and fed a controlled diet with those living at sewage treatment plants and feasting on earthworms inhabiting the rocky filter beds.  http://louisijisheehan.blogspot.com  Since the worms survive on microbes that degrade the sewage, the treatment-plant starlings consumed natural human estrogen along with three estrogen mimics: DEHP, used to manufacture polyvinyl chloride; DBP, found in nail polish; and bisphenol A, common in hard plastic bottles.  http://louisijisheehan.blogspot.com

At first, both groups of starlings appeared to behave normally, exhibiting a natural seasonal cycle in which “the whole [brain] mechanism for song shuts down in autumn, presumably to make room for other centers that are more important—like finding food,” says Katherine Buchanan, a study leader. When the spring mating season rolled around, estrogen in the male brain surged in both groups, triggering an expansion of the vocal center and a burst of song. But for birds consuming the estrogen cocktail, the vocal center grew even larger—and they sang five times as long as uncontaminated birds and composed more complex songs. In the lab, female starlings showed a preference for those songs, perching near a loudspeaker that was playing them.

Blood tests, however, showed that the doped male starlings had compromised immune systems, suggesting that they were less fit. The starling population in Britain has dropped by half in the last four decades, Buchanan says, mostly because humans have been encroaching on their habitat—but perhaps also because pollutants are creating a siren song that has bewitched the females, luring them to reproduce with more musical, but less healthy, mates.

  Louis J. Sheehan    POISON IVY is one of those weeds proliferating like mad as rising levels of greenhouse gases like carbon dioxide heat up the atmosphere. Researchers at Duke University who studied the weed between 1999 and 2004 in a controlled forest area near Chapel Hill, N.C., where high levels of CO2 are pumped into test plots, found that poison ivy not only grew more vigorously, but also produced a more toxic form of urushiol, the resin that causes its rash.  http://louis5j5sheehan5esquire.blogspot.com

Some people, though, rather than cursing the proliferation of the itchy vine, are mining it as a growth opportunity.

Umar Mycka, a horticulturist with 35 years of experience at the Philadelphia Zoo, has started a business (poisonivyhorticulturalist.com) removing poison ivy for people who don’t want to get near the stuff.  http://louis5j5sheehan5esquire.blogspot.com

“They come to me like this,” Mr. Mycka said, holding his forearms out, as if covered with the red rash or blisters. “Sometimes their head is out to here,” he added, alluding to the swelling that can occur in acute cases, which may require steroids or even hospitalization. “When it’s that bad, people say, oh, it must have been poison sumac or poison oak,” he said. “It’s not. It’s just that they got it under optimum conditions.”

What are optimum conditions? Picture a meadow or woods on a humid, overcast day, when those resins are pumping through the poison ivy vines, which run along the ground and up the trees. Along comes somebody who has never heard that old saw “leaves of three, let it be,” wearing low shoes or sandals, shorts and a sleeveless shirt. Or maybe someone decides he’s going to clear overgrown brush in the backyard, wearing gloves and a short-sleeved T-shirt.

Robert Shiffrin, a homeowner in Wynnewood, Pa., a suburb of Philadelphia, recently made that mistake. “I didn’t think to look around,” he said. “I was more interested in the pricker bushes; I wore gloves. But I got this wall-to-wall rash from my wrists to the end of my short sleeve.“

Last week, he followed Mr. Mycka to the edge of his yard, where poison ivy was growing beneath a sassafras tree and up into its limbs. Mr. Shiffrin had such a bad rash, he made the same assumption many others do: “I thought it was poison sumac or poison oak,” he said. “But Umar told me they don’t grow here.”

Poison sumac, Mr. Mycka said, grows in swamps on the East Coast, but there was no bog in Mr. Shiffrin’s yard. Poison oak is actually two species: Western poison oak, which grows on the West Coast, and Eastern poison oak, which frequents sandy habitats like the Pine Barrens in New Jersey, where it grows as a shrub, not a vine. Eastern poison ivy (Toxicodendron radicans) is far more ubiquitous, flourishing just about everywhere east of the Mississippi River. According to Jean H. Langenheim, whose book “Plant Resins: Chemistry, Evolution, Ecology and Ethnobotany” (Timber Press, 2003) is one of Mr. Mycka’s bibles, poison ivy is also found in Mexico, Guatemala and East Asia.

“Capt. John Smith named it poison ivy because he thought it looked like English ivy, which has aerial roots,” Mr. Mycka said, referring to the English explorer who helped found Virginia. (Captain Smith also compared the plant to Boston ivy, which has tri-foliate leaves, Ms. Langenheim writes, and he noted in his 1624 “Generall Historie of Virginia, New-England and the Summer Isles” that it caused “itchynge” and blisters.)

“To me, it’s a menace, but I have respect for it,” Mr. Mycka said last week, as he painted Vine-X, which contains triclopyr, a systemic herbicide, on a poison ivy plant growing in a thick ground cover beneath spruce trees. “When I paint this on, it isn’t coming back.”

Dressed in a white Tyvek jumpsuit, made of spun polyethylene, and booties, Mr. Mycka knelt in a little sea of lily of the valley, tracing, with double-gloved hands — plastic first, then heavy work gloves — the three-leafed vine that ran along the ground and straight up the trunk of the tree. “Birds probably brought the seed in,” he said. “This is all the same plant, probably five years old.” He pointed out this year’s growth — about 10 inches of green stems and seven sets of leaves — extending from the woody vines hugging the ground. “Can you smell it?” asked Mr. Mycka, who described the smell as having “a bitter taste.” I couldn’t smell, or taste, a thing.

Then he held the Vine-X bottle, which had a tiny brush attached to its cap, upside down, and continued applying the herbicide with the delicacy of a weed-killing Rembrandt.

The herbicide is applied to the stems and goes down into the roots, where it kills the plant. The compound’s half-life — the time required for half of it to break down — is 46 days. But studies indicate that residues can remain in the soil for about a year. It is not clear how toxic it might be to mammals, fish or ducks — so I, for one, would rather just pull up the weed.

Roundup, or glyphosate, another systemic herbicide widely used for poison ivy control, has a half-life of 32 days, and dissipates for the most part within six months, according to Monsanto, its manufacturer. But its surfactants — the wetting agents used to spread the chemical — are harmful to fish and frogs. Thick stems clinging to trees can be cut and painted with Vine-X or Roundup, but care must be taken to avoid damaging the tree and the surrounding plants. At this advanced stage, poison ivy can send out horizontal branches with so many big, dark green leaves, it looks like a tree itself.

Instead of using poison, organic gardeners pull up the vines and roots (wearing gloves, of course), and immediately dispose of them in garbage bags headed for the landfill. Mike McGrath, the voluble host of “You Bet Your Garden,” broadcast weekly on WHYY in Philadelphia (whyy.org/91FM/ybyg/index.html), puts plastic shopping bags (the heavy kind from upscale department stores) over his gloved hands, and pulls the vines in such a way that even his gloves don’t touch any part of them. He also wears protective clothing, and washes everything — tools, gloves, clothes, body — with cold water, as soon as the job is done.

When it comes to removing even the tiniest bit of urushiol from the hands or anywhere else on the body, there is a lot of conflicting advice. Some recommend washing with a soap like Fels-Naptha and warm water; others, like Mr. McGrath, say that that just spreads the resin, and that only cold water, sans soap, will do. Still others, myself included, swear by jewelweed, a soft, green-leafed plant with little orange flowers that often grows next to poison ivy in damp areas, near streams. Crush the stems and leaves, and rub the sap over your arms and any other infected area (Mr. Mycka uses jewelweed in ice cubes), and the jewelweed sap breaks up the resin. Or so we believe, anyway. We’re waiting for the double-blind study.

One thing everyone agrees on is that however poison ivy is controlled, it should not be burned — not even the dead leaves and vines — because the resin-filled smoke can irritate the skin and damage eyes and lungs.  http://louis5j5sheehan5esquire.blogspot.com

Mr. Mycka, who has an associate’s degree in horticulture from Temple University, tries to educate his clients about what poison ivy looks like and how it grows, including its dispersal by birds that survive the winter on its white berries. Beneath the spruce tree, he pointed out some hefty specimens: the top, or middle, leaf was more rounded and perched a bit higher than the others thanks to a leaf petiole or stem. The side leaves were a bit more toothed. But individual plants can vary widely in appearance.

“The plant ambushes people, because they don’t know what it looks like,” Mr. Mycka said. Sometimes the leaves are smooth; sometimes they are indented or toothed. In the spring, they are small and reddish; by deep summer, they are dark and shiny.

Mr. Mycka would love to see Americans discover some use for the plant. “In China and Japan, they made lacquer out of their resin plants, so they understand and value it,” he said. “Whereas we just see it as that darn weed over there.”

Louis J. Sheehan, Esquire  At least a quarter of the planet’s reef-building corals face a noticeable risk of extinction, according to the first large scale review of hundreds of species.

Out of 845 known species of warm-water corals, 231 meet the criteria for listing in worrisome categories on the international IUCN Red List of Threatened Species, says marine biologist Kent Carpenter of Old Dominion University in Norfolk, Va.  http://louis5j5sheehan5esquire.blogspot.com

The troubled species fall into the vulnerable, endangered or critically endangered categories on the Red List, which is maintained by the conservation group International Union for Conservation of Nature and Natural Resources.

If the coral species keep declining, coasts could lose the storm protection and other ecological benefits healthy reefs provide, Carpenter warns. Reef breakdown would have “huge economic effects on food security for hundreds of millions of people dependent on reef fish,” Carpenter and 38 co-authors conclude in a paper to be published in Science that appeared online July 10.

“The Carpenter paper has some scary conclusions,” says marine biologist Jenny Waddell of the National Oceanic and Atmospheric Administration’s reef programs in Silver Spring, Md. She points out that the new paper’s proportion of corals in trouble exceeds the threatened portion of most other big groups of land animals except amphibians.  http://louis5j5sheehan5esquire.blogspot.com

Carpenter says the new roll of threatened reef corals will be added to the IUCN’s list, increasing 20-fold the number of corals the group tracks.

Monitoring of marine species has lagged compared with terrestrial species, he says. Out of some 40,000 total species the IUCN had evaluated up to now, only 1,400 species live in the sea.

To catch up, the IUCN and environmental group Conservation International fund the Global Marine Species Assessment to review major groups of creatures. For a year and a half, Carpenter has led an international team of marine biologists working through the known species that build classic shallow-water reefs.

Skimpy information kept the researchers from evaluating 141 coral species. For the others, the biologists worked out trends in population growth or decline.

Reports on shrinking areas of reefs have long indicated trouble for corals, but “we brought a new dimension,” Carpenter says. At the final tally of 231 imperiled species, “everyone’s jaw absolutely dropped.”

Two main kinds of miseries beset the corals, Carpenter says.

Climate change is taking a toll as warming sea water raises the risks of disease and coral bleaching (when corals lose their symbiotic algae and thus face nutrient shortages).

Abundant local threats also hammer corals. Sediments erode into the sea from frenetic development booms along coasts, and boats drag anchors over reefs, smashing structures that took hundreds of years to build.

“If we can control local threats, it will buy us some time,” says Andrew Baker of the University of Miami. “But ultimately corals will face some pretty tough challenges due to high temperatures and acidity.”

That worldwide process of ocean acidification is already altering surface water chemistry as those waters absorb excess carbon dioxide from the atmosphere. Though seawater is not acid now and isn’t expected to become so, the shift could disrupt ecosystems. “The new species analysis’ methods didn’t address this threat,” comments Maoz Fine of Bar-Ilan University in Ramat-Gan, Israel, so it “may require a category updating very soon.”

In the audit’s regional view, Caribbean reefs have the largest proportion of corals in the most threatened categories, the paper shows. “I used to dive in the Caribbean — the reefs were gorgeous,” Carpenter says. “Now, to use a technical term repeated frequently around here, they’re toast.”

Caribbean reef vulnerability also showed up in a NOAA report co-edited by Waddell and released July 7 at the International Coral Reef Symposium in Fort Lauderdale, Fla. Every three years, the NOAA reef research program presents a status report on the reef communities off the continental coast and U.S.-related islands.

The 2008 report found 69 percent of Pacific reefs in good or excellent condition but only 25 percent of Caribbean and Atlantic ones ranking that high.

Disturbing as both reports are, Carpenter calls for action, saying “there is hope.”

Brainpower by itself seems to be a force in evolution, at least in developing diversity of body size in birds, two researchers report in the August American Naturalist.  http://louis4j4sheehan4esquire.blogspot.com

Bird families with relatively big brains, such as parrots and woodpeckers, tend to have diversified a bit faster than less-endowed species, report Daniel Sol of the Autonomous University of Barcelona and Trevor Price of the University of Chicago.  http://louis4j4sheehan4esquire.blogspot.com

Brainier lineages are more likely to show extra variety in body size, with hefty species having little handful-of-fluff relatives, according to the new analysis. In studying diversity, Sol and Price focused on the variety in body mass, for which there’s broad data. But other changes, perhaps in food or habitat, go along with this diversity in size.

Brain size nudging along the evolution of body size makes sense according to a scenario proposed in the 1980s, Price says. In theory, large-brained lineages could have lots of innovators willing to peck at new food or find a way to open a seed case or shell. Such technological breakthroughs could spread if the species learned quickly.  http://louis4j4sheehan4esquire.blogspot.com

Those brainy, innovative animals thus stand a better chance of exploiting a new food or successfully colonizing a new place. And both those accomplishments can expose a population to new forces of natural selection that reshape its future.

Looking for effects of brain size hasn’t been easy. Studies kick up debate over what aspects of the brain to measure and how to compare them. However, researchers such as Louis Lefebvre of McGill University in Montréal have made a case for linking outsized brains to a capacity for innovation.

To test for brain effects on evolution, Sol and Price used published data to establish an average body mass for each of some 7,000 bird species in 120 families. Other records provided brain mass for each of the species, and the researchers worked out which families tended to have the biggest brains relative to body size.

Then researchers reviewed the families, comparing typical brain size (relative to body size) with the variety of body sizes among the species within that family. The researchers also adjusted for the age of a lineage, since more ancient ones would have had more time to diversify. At the end of the analysis, brain size by itself has its own effect, albeit small, on whether a family showed a large variety of body sizes.

“Species with bigger brains tend to evolve more quickly in body size,” Price concludes. Parrots, woodpeckers, hornbills, owls, lyrebirds and crows ranked high both in brains and in diversity in body size. In contrast, pheasants, cormorants and quail didn’t have particularly big brains or much diversity within their families.

The basic premise about the bigger-brained birds invading new niches with new circumstances to shape their evolution sounds like “a pretty good idea,” says Georg Striedter of the University of California, Irvine, who studies brain evolution and birds.

Working with the size of the whole brain and with body weights may not be perfect tools for testing the idea, he says, “but you have got to start somewhere.”

http://louis2j1sheehan2esquire.blogspot.com  Tasmanian devils are mating earlier in response to a deadly, contagious cancer, a new study reports. The findings, appearing online July 14 in Proceedings of the National Academy of Sciences, are among the first to show mammals adjusting mating behavior in response to an infectious agent.

“There has been a sudden increase in the proportion of females that breed in their first year of life as subadults,” says lead author Menna Jones, a zoologist at the University of Tasmania in Hobart, Australia. “This shift has been fast, within one generation.”

Previously, fewer than 10 percent of the females reproduced in their first year of life. Now up to 60 percent breed in the first year, Jones notes.

“This is a dramatic finding, showing that breeding patterns change as a response to disease,” says Christopher Johnson, an ecologist at James Cook University’s Townsville campus in Australia.

Tasmanian devils are carnivorous, dog-sized marsupials that inhabit the island of Tasmania, off the southeastern coast of Australia. From a peak around 130,000 to 150,000 in the mid 1990s, the devil population has dropped to between 20,000 and 50,000, according to a report from Australia’s Department of Primary Industries, Water and the Environment.

The devil population has been ravaged by a contagious cancer called Tasmanian devil facial tumor disease, which first emerged around 1996. The disease, which spreads when the frisky devils bite each other, causes huge lesions to grow on a devil’s face and jawbone. All of the infected animals die, usually after the fast-growing tumors make eating impossible. Because the devils lack genetic diversity, they can pass on tumor cells to each other without their bodies recognizing those cells as foreign, Jones says.  http://louis2j1sheehan2esquire.blogspot.com

Because the disease kills most of the animals by the time they’re 2 years old, early breeding keeps the devil population numbers up. That may stave off extinction long enough for the animals to evolve ways to reduce disease’s impact, Jones says.  http://louis2j1sheehan2esquire.blogspot.com

With the devil population plummeting, there’s more food to go around, which seems to increase the female devils’ growth rates, Jones says. That could account for their early sexual maturation.

It’s not clear whether the epidemic has led to permanent genetic shifts in when the Tasmanian devils mature, Johnson says. It’s possible that devils who are hard-wired to mature early are able to reproduce, while relatively late bloomers die of the disease before they can have offspring. Over time, those who are genetically programmed to grow up fast may become the norm in the population.

Past studies have shown that deer and commercially harvested fish can breed earlier in response to heavy predation or hunting pressures, Jones says. But this is the first time such a shift in sexual maturity has occurred in response to an infectious disease, she says.

Louis J Sheehan 

 

Pesticides have greatly boosted agricultural yields over the last half century, so it is no wonder, given the commercial availability of many of these synthetic chemicals, that American homeowners apply 100 million pounds of the stuff each year to make their own gardens grow bigger and faster, too.

But the downside of using such chemicals is that they can poison people and pets as well as backyard wildlife: “Common insecticide ingredients such as 2,4-dichlorophenoxyacetic acid (2,4-D), atrazine and dicamba have been shown to harm mouse embryos at times equivalent to the first week after conception in humans,” says Erica Glasener of The Green Guide. Due to such revelations, home gardeners are fast discovering the benefits of avoiding chemicals in favor of natural, less toxic alternatives.  http://louis2j1sheehan2esquire.blogspot.com

But before thinking about applying pesticides, gardeners can design (or re-design) their gardens to make the most of native plants that have evolved over eons to thrive in local conditions without synthetic aid or lots of water. Choosing native plants appropriate to your elevation, soil type, drainage and sun exposure will naturally repel many common pests and also reduce the propagation of invasive exotic species.

Similarly, embedding your plants in healthy soil replete with beneficial insects and worms can also help reduce the need for pesticides. Laura Moran of Mainstreet.com suggests that home gardeners compost their vegetable food waste—which is chock full of nutrients that plants love—and mix it into existing soil to give the garden a healthy boost. “Aside from stimulating healthy root development,” she writes, “the addition of rich compost also improves soil texture, aeration and water retention.” It also provides a nice home, she says, for the beneficial bugs that are destroyed along with the bad ones by chemical pesticides.  http://louis2j1sheehan2esquire.blogspot.com

If pesticides are necessary, there are a handful of organic varieties available. Bacillus thuringiensis (“Bt&rdquo is a naturally occurring bacterium that is lethal to most leaf-eating caterpillars on trees, shrubs, flowers and vegetables. According to gardening writer Jeff Ball, it is harmless to all other insects, animals and humans. It comes in a powder form for use as a dust, or, when diluted with water, as a spray. Organic chemists have formulated varieties of Bt to kill mosquitoes or potato beetles as well.

To control slugs in an environmentally friendly manner, The Green Guide’s Glasener suggests recycling the black cell packs that vegetables and annuals are sold in, and placing them (empty) upside down near the base of plants. “Each morning, check the containers for pests, and if you find any, simply throw the container away with the pests inside,” she says. Another easy slug control method is to use hollowed out grapefruit rinds in a similar manner around the base of plants, disposing of them if they turn up any slugs.

Pet owners may already be familiar with insecticidal soaps used to control fleas. Some of these soaps can also be used in the garden to repel insects. For more information, consult a local nursery specializing in organic methods and native plants. Find one near you via the free online Native Plants Nursery Directory.

 

Louis J Sheehan 

Australia's endangered Tasmanian Devil, its numbers decimated by an infectious facial cancer, is mating earlier, scientists have found.

"To our knowledge, this is the first known case of infectious disease leading to increased early reproduction in a mammal," they wrote in the latest issue of the Proceedings of the National Academy of Sciences.

The disfiguring facial cancer, which often kills within months, has cut the island state's wild devil population by as much as 60 percent and it could become extinct in 10 to 20 years.

But a study covering five sites found that juvenile females, or those around a year old, were becoming sexually more precocious.  http://louiskjksheehan.blogspot.com

Before the disease in 2000, between zero and 12.5 percent of 1-year-old females bred. But after the disease started spreading, precocial breeding increased at one site to 13.3 percent by 2004. That figure jumped to 83.3 percent in 2006.

"Before the disease, the modal female began seasonal breeding at age 2 and produced a litter annually for 3 years, with ... death occurring in her fifth or sixth year," they wrote.

"Females now generally have one breeding opportunity and may not survive long enough to rear that litter."

The facial cancer is spread directly between devils through biting during the mating season.

The Tasmanian Devil is a carnivorous marsupial about the size of a small muscular dog. It has black fur, gives off a skunk-like odor when stressed and earns its devil name for its ferocious temperament and disturbing call.

Every earthquake starts small. Beginning at one point, it extends outward, causing tremors in and around its path. At some point, though, all earthquakes stop. So what brings this mighty process to a halt?  http://ljsheehan.blogspot.com

That’s an important question, because the duration of an earthquake helps determine how much damage it will do. Will the tremor be of mild magnitude—say, a magnitude 4 on the Richter scale, the kind that occur all over the world every day—or a 9, which happens no more than once a decade on average?  http://ljsheehan.blogspot.com

To understand what makes an earthquake stop, it’s important to understand what makes it go: the release of energy stored in rocks clustered around a fault, which separates masses of the earth’s crust known as tectonic plates. These rocks are held in place by friction. As time goes by, the movement of the plates causes the rocks around the fault to bend and stretch. That, in turn, causes the rocks to store energy, like compressed springs. http://ljsheehan.blogspot.comEventually, friction across the fault isn't able to hold the rocks back, and a crack is created across the fault as it begins to slip. This releases part of the built-up energy, some of which creates the seismic waves that travel to the earth’s surface and cause damage.  http://ljsheehan.blogspot.com

Earthquakes stop when there isn’t enough energy to keep them going. The energy released by the sliding fault needs to be enough to overcome the friction holding rocks in place. Once the earthquake comes up against too much friction, it will stop.

An earthquake can be stopped in its tracks, for example, when the crack on the fault hits material that doesn’t slide as easily—in other words, that has more friction. An analogy would be skiing off of snow onto dirt—you will stop pretty quickly. Hitting the site of a recent earthquake can also stop a tremor, because such areas don’t have enough built-up energy to propel an earthquake. A third possibility might be that the fault simply ends; the amount of energy required to cut a new fault into intact rock is far greater than the amount required to break an existing fault.

Then again, earthquakes can jump from one fault to another, often as far as 2.5 miles (4 kilometers) apart. So just as you never know when a big one will hit, it’s hard to say when it might stop.

Louis J Sheehan In exchange, the U.S. agreed to share its expertise on exterminating other invasive bugs, such as fire ants. Officials at the U.S. Department of Agriculture (USDA) say the move could help prevent the international transport of a faster-spreading and particularly destructive Asian gypsy moth variety.

The deal with China is the fourth the U.S. has cut in an attempt to get a handle on the problem; it has more extensive agreements with Russia, Japan, and South Korea. Mike Simon, an offshore pest mitigation expert with the USDA's Animal and Plant Health Inspection Service (APHIS), says scientists in China are set to begin trapping and studying gypsy moths this month.

The North American gypsy moth is blamed for defoliating trees in national forests and residential areas in at least 20 states as well as across southeastern Canada. U.S. Forest Service officials say that aerial pesticide spraying of hundreds of thousands of acres each summer has slowed but not stopped the moths. They add that they are trying to keep a lid on the native population as well as prevent the more virulent Asian variety from reaching U.S. soil.

The Asian moth made two minor incursions into U.S. ports during the 1990s, but both times were quickly eradicated. Over the past year, inspectors have again found Asian egg masses on foreign ships arriving in U.S. ports. U.S. Customs and Border Patrol agents are authorized by law to bar entry to foreign vessels carrying invasive bugs or their eggs and to order them offshore to be scrubbed of the pests before unloading cargo. But Simon says it would be more effective to verify that no eggs, caterpillars or adult moths are aboard ships before they set sail from overseas ports.

The main concern: that the virulent strain of Asian gypsy moth, if introduced to the U.S., could exacerbate damage to North American forests.

"The west coast states are basically terrified; it would be devastating to their timber resources, both for industry and recreation," Simon says. That's because, other than a few isolated and quickly squashed outbreaks, the U.S. west coast is generally free of gypsy moths. Without competition from local populations, any Asians that arrived there could thrive.

At least 10,000 cargo containers and 100 ships arrive daily in the Port of Los Angeles, most of them from Asia, which poses a real risk, he adds.

The North American strain, Lymantria dispar, now stretches from Canada into North Carolina, Minnesota and Wisconsin, with pockets of infestation beyond its contiguous range. It is currently expanding its  reach by about five miles (eight kilometers) a year, according to ecologist Patrick Tobin, head of the technical advisory committee* for the U.S. Forest Service's Slow the Spread, a program to manage the gypsy moth.

As its name suggests, the program, which was first funded by Congress in 2000, is trying to decelerate the expansion of the gypsy moth's range. http://louiskjksheehan.blogspot.com  It monitors 10 states along the region's leading edge for outbreaks and decides which ones to combat with insecticides. It also educates truckers, plant nurseries, the timber industry, motorists and recreational forest users about ways to avoid transporting the pest. Human movement helps the gypsy moth move faster than it does on its own.

At the peak of its migration, in the 1980s the gypsy moth was spreading southward and westward across the U.S. by about 13 miles (20 kilometers) per year. But dead trees aren't the sole concern: Gypsy moths' hair and scales contain histamines, which can cause allergic reactions in humans sensitive to them.

As it turns out, L. dispar females cannot fly (because they lack the muscle strength and wing length of their Asian cousins); they advance when larvae suspended on strands of silk are carried by the wind—or even farther and faster by cars, trains and trucks. The adult males, meantime, are long-distance flyers that establish new colonies by sniffing out the pheromones of adult females that grew from transported larvae.

The adult female's inability to fly has helped limit the spread of gypsy moths across North America. An L. dispar egg also requires a long winter chill and the hatched caterpillars generally eat the foliage of oak, poplar, and birch trees. Their Asian cousins can hatch more quickly and have a more eclectic diet that also includes Douglas fir, red maple, pine and cottonwood, says entomologist Melody Keena, a Forest Service supervisory researcher. The introduction of the Asian variety, should it mate with the local population and pass along those traits, could accelerate the spread and endanger additional tree species, she adds.

In experiments that began more than a decade ago (after minor incursions of flying strains were quickly eradicated in the southern and western U.S.), Keena and her group demonstrated for the first time that, when Asian and North American gypsy moths mate, the offspring female develop the ability to fly. That could help them advance into forests that are currently free of infestation.

Gypsy moths are believed to have been introduced into North America in 1869 after an amateur entomologist brought larvae back with him from Europe, most likely from France. He accidentally allowed some larvae, presumed to have been L. dispar, to escape from his backyard outside Boston, where he was keeping and studying his new colony. From there, it began inching across the continent.

Now, it appears Asian strains are gradually moving across Europe and interbreeding with L. dispar there. Resulting hybrid females in Croatia, Portugal, France and Greece still cannot fly, but major populations in Lithuania, Poland and Germany can, according to Keena.

Although Keena and other scientists say that suggests a scenario in which L. dispar interbreeding with Asians might produce flying offspring that could accelerate the spread, Tobin notes that their dispersal could be limited by still larger populations of native L. dispar.

If there were to be an influx of Asians, the areas most affected would likely be those where the L. dispar population is scarce—west and south of the Virginia–North Carolina border, eastern Wisconsin and northern Minnesota—and especially in the west where it's nonexistent, Tobin says. In those places, where the Asian traits are less likely to be diluted by mixing with L. dispar, the Asians could dominate.

Vic Mastro, director of the APHIS research lab in Otis, Mass., says agriculture officials have set around 350,000 traps in the western part of the country. But there's a hitch: Baited with pheromone, they only attract males and leave scientists guessing whether any flying females are in the area. So the traps alone are not enough, and it's more crucial to keep the Asian variety out altogether by inspecting ships in ports before they enter the U.S., Mastro says.

"Right now, if we find egg mass on a ship, we assume the worst," he says.

The current agreement calls for scientists to set similar traps in forests around Chinese ports. The traps could confirm large populations, providing the evidence U.S. officials need to back up arguments for cargo inspections.

Past studies have shown that gypsy moths are attracted to light; they swarm from infested forests to the bright lights of nearby port cities and docked ships. Once an infested ship docks in the U.S., its infested containers can also disperse quickly.  http://louiskjksheehan.blogspot.com

This summer, the U.S. is seeing massive gypsy moth outbreaks in Pennsylvania and northern New Jersey. But nowhere is the gypsy moth's attraction to light more apparent than in far eastern Russia, which is in the second year of its worst outbreak since the early 1990s, says Steven Munson, the U.S. Forest Service’s team leader for the overseas monitoring program. He notes that larval caterpillars have been chewing through the vast forests around two major shipping ports—Vostochnyy and Nakhodka—near the Chinese and North Korean borders. U.S. scientists headed there last week to help check traps and search for egg masses, he says.

A naturally occurring virus helps structure gypsy moth infestations into cycles: An outbreak may last three years before the virus sends a population into dormancy for more than 10 years, Munson says. By mid-August, when the female Russian moths typically emerge from pupae and start laying eggs, researchers should know whether to step up ship inspections there or whether the