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UPI NewsTrack Health and Science News

Climate change aids invasive plants

CAMBRIDGE, Mass., Feb. 9 (UPI) -- Harvard University scientists say they've determined invasive plants could become more prevalent and destructive as climate change continues.

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The scientists, led by Assistant Professor Charles Davis, said they analyzed more than 150 years of data and discovered non-native plants, especially invasive species, appear to thrive during times of climate change because they're better able to adjust the timing of annual activities, such as flowering and fruiting.

"These results demonstrate for the first time that climate change likely plays a direct role in promoting non-native species success," Davis said. "Secondly, they highlight the importance of flowering time as a trait that may facilitate the success of non-native species."

Davis and his colleagues said they analyzed a dataset that began with Henry David Thoreau's cataloging of plants around Walden Pond during the 1850s. Since then, the mean annual temperature in the vicinity of Concord, Mass., has increased by 4.3 degrees Fahrenheit, causing some plants to shift their flowering time by as much as three weeks in response to ever-earlier spring thaws, the scientists said.

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"We set out to use this dataset to examine which plants have been the beneficiaries of climate change," Davis says. "Our research suggests quite decisively that non-native and invasive species have been the climate change winners. Climate change will lead to an as-yet unknown shuffling of species, and it appears that invasive species will become more dominant."

The research appears in the online journal PLoS One.


Differences between Crohn's and colitis

SWANSEA, Wales, Feb. 9 (UPI) -- British researchers said they found distinct demographic profiles for Crohn's disease and colitis -- inflammatory bowel diseases.

Researchers at the School of Medicine, Swansea University and the University of Oxford analyzed data for 3,000 patients hospitalized in Wales from 1999-2007. They found several demographic differences between patients with severe Crohn's disease -- inflammation deep into tissues anywhere in the digestive track -- and patients with ulcerative colitis, inflammation including ulcers in stretches of the lining of the large intestine and rectum.

The study, published in the World Journal of Gastroenterology, found the prevalence of Crohn's disease was higher in females, 57.4 percent, than in males, 42.2 percent, and was highest in people ages 16-29. However, the prevalence of ulcerative colitis was similar in females and males -- about 50.1 percent -- and increased continuously with age.

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Mortality was 6.8 percent and 14.6 percent after one and five years follow-up for Crohn's disease, and 9.2 percent and 20.8 percent after one and five years for ulcerative colitis.

"The hospitalized prevalence of severe Crohn's disease was slightly higher among the most deprived groups but there was no association between social deprivation and severe ulcerative colitis," the study authors said in a statement.


Study assesses effects of earlier springs

WALLINGFORD, England, Feb. 9 (UPI) -- U.K. scientists studying global change say they've found the trend toward earlier springs and summers has affected a wide range of plants and animals.

The collaborative study, involving scientists from 12 U.K. research institutions, universities and conservation organizations, is said to be the most comprehensive assessment so far of long-term changes in the seasonal timing (phenology) of biological events across the United Kingdom's marine, freshwater and terrestrial environments.

Led by Stephen Thackeray and Professor Sarah Wanless of the Center for Ecology & Hydrology, the researchers said they analyzed more than 25,000 long-term phenology trends for 726 species of plants and animals.

The study, among other things, found more than 80 percent of trends between 1976 and 2005 indicate earlier seasonal events. On average, the seasonal timing of reproduction and population growth has become earlier by more than 11 days over the whole period, but the scientists said that change has accelerated during recent decades.

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"It is important to realize that this analysis doesn't identify which predator-prey relationships are most at risk of disruption due to changes in timing," said Wanless. "What it does do is highlight that the recorded changes need urgent investigation, particularly for species with high economic or conservation importance."

The study's findings are detailed in the journal Global Change Biology.


Yale scientists study preterm birth

NEW HAVEN, Conn., Feb. 9 (UPI) -- Yale University School of Medicine researchers say they may have discovered how the hormone progesterone functions to prevent preterm birth.

Preterm birth -- delivery prior to 37 weeks gestation -- has become increasingly common during the past 40 years, researchers said, but such premature infants are at least seven times more likely to die or have long-term neurologic injury compared with infants delivered at term.

Efforts to prevent preterm birth have been largely unsuccessful, but some studies have suggested progesterone supplementation from weeks 16-20 of gestation through 36 weeks might prevent some preterm births. But the molecular mechanism by which progesterone acts has not been known.

The Yale study shows, for the first time, progesterone can prevent premature rupturing of the fetal membranes that occurs from a weakening of the membranes by apoptosis -- programmed cell death.

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"We were able to demonstrate that progesterone prevents apoptosis in an artificial environment in the laboratory in which we stimulated healthy fetal membranes with pro-inflammatory mediators," said Professor Errol Norwitz, who led the study. "Interestingly, and somewhat unexpectedly, we also saw an inhibition of apoptosis under basal conditions without the presence of pro-inflammatory mediators. This suggests the same mechanism may also be important for the normal onset of labor at term."

The findings were presented in Chicago last week during a meeting of the Society for Maternal-Fetal Medicine.

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