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Tag: "rates" at biology news

Penguin chicks exposed to human visitors experience spike in stress hormone

...rt-term negative effects, such as different growth rates or weight differences at fledging, caused by distinct differences in corticosterone levels between newly hatched chicks in tourist and non-tourist areas of the reserve, Walker said. But it is unclear what later effects the elevated stress hormones mi...

Genetic discovery could lead to drought-resistant plants

...d the University of Lancaster compared the cooling rates of plants with normal, high and low levels of gene activity. From their data, they were able to link the gene to plant exhalation. The discovery is another step in understanding how plants respond to their environment. In hot temperatures, plants ke...

Drug resistance testing in treatment-naive HIV patients is cost-effective

... compared with no resistance testing. Resistance rates vary from place to place. It is estimated that, in the United States and Europe, the average resistance rate in treatment-naive patients is between 8 and 10 percent, although baseline resistance may be as high as 16 percent in gay men, "likely reflec...

Primate virus jumps species barrier to humans for first time in Asia

...erspecies interaction there is very different, and rates of human-monkey contact are much lower." Limiting dangerous contact between primates and humans can have other benefits, as well, such as reducing the transmission of human infections to monkeys. Human measles, for instance, can cause disease in mon...

Researchers predict infinite genomes

...an-genome. That raises interesting questions about rates of evolution, notes Fraser. "We're intrigued to learn more about the diversity within a given species, and how it happens," she says. ...

Use of high hydrostatic pressure to inactivate Hepatitis A virus in oysters studied

...ths, but can linger as long as six. While survival rates for Hepatitis A are above 99 percent, the disease can be very dangerous for infants, the elderly, immunosuppressed people, and those with existing liver disease. Bivalve shellfish, such as oysters, have been demonstrated to concentrate pathogenic or...

Traditional models underestimate extinction rates

...luded did the models match the observed extinction rates in the flea experiments. When density dependence was not included, extinction rates were greatly underestimated. Drake's results underscore the importance of bolstering extinction mod...

New understanding of jet lag

...f the SCN clock." He suggested that the differing rates of synchronization that occurs in the central clock may be part of a complex evolutionary adaptation to seasonal light changes, but the mechanism, in effect, becomes confused when confronted with unnatural and dramatic shifts in light schedules. The...

High carbon dioxide levels spur Southern pines to grow more needles

...orest," she said. All trees undergo their highest rates of leaf area accretions before canopy closure, and that could lead to uncertainty about whether normal needle growth spurts or CO2 effects were responsible for higher counts, she explained. "I'm trying to draw the distinction between closed canopy v...

DNA from feathers tells tale of eagle fidelity

...e said. Those parameters, such as yearly survival rates and ratios of males to females, help conservation biologists monitor populations of rare or endangered species. Noninvasive sampling allows biologists to track changes in populations over time without the risks associated with handling live animals, ...

UCLA scientists reveal how Nipah virus infects cells

... devastation to the country. In Bangladesh, death rates of repeated outbreaks of Nipah virus in the past four years have risen to 70 percent, suggesting that the virus is growing more lethal. ...

Freeze-dried mats of microbes awaken in Antarctic streambed

...mats in the experimental channel had higher growth rates than mats in adjacent streambeds receiving annual summer water flow, she said. The study showed the new microbial mats were taking up atmospheric nitrogen at a higher rate than mats in adjacent streambeds, increasing biomass productivity, she said. A...

Mosquitoes are more attracted to individuals infected with malaria

...cipants. It is already known that mosquito biting rates greatly influence the spread of malaria. Now Koella and colleagues have shown that the parasite itself manipulates the biting behaviour of the mosquito vector when it is ready for a new host. Such manipulation could have a profound effect on the epid...

NASA satellite data provides rapid analysis of Amazon deforestation

...k and lead author of the new study. Deforestation rates in tropical Africa, Southeast Asia, and South America have remained constant or have increased over the past two decades, altering global carbon and climate while elevating the need for frequent and accurate assessment of forest loss. In the Brazilia...

Tropical Deforestation affects rainfall in the U.S. and around the globe

...n climate policies, especially since deforestation rates in tropical Africa, Southeast Asia, and South America have remained constant or have increased over the past two decades. Land-cover change, depending on its nature, can either mitigate or exacerbate greenhouse warming. The researchers caution that ...

Experimental shingles vaccine proves effective in nationwide study

... placebo. The vaccine was well tolerated, with the rates of serious adverse events low and local reactions at the vaccination site generally mild. "As people live longer, and the proportion of older people in our population increases, it is highly likely that the prevalence of shingles will increase. A pr...

Studies clarify risk factors for mother-to-child transmission of hepatitis C virus

...vel finding of a gender difference in transmission rates and suggested that higher HCV rates in female newborns may be due to excess mortality in infected males in utero. "Overall, the observat...

'Patient-choice' C-section rate rises 36%: HealthGrades study

...which there is no medical necessity. Complication rates from "patient-choice" C-sections are one factor in..., Florida, New York and New Jersey had the highest rates of "patient-choice" C-sections in the latest year studied, 2003. The rates and percentage increase o...

Hunger in America rises by 43 percent over last five years

...ar poverty continuing to suffer from severely high rates of both food insecurity and hunger. California, T...South Carolina all have food insecurity and hunger rates that are significantly higher than the national average. The lone bright spot in the nation is Orego...

New study shows measles immunization may prevent fatal brain infection

...United States during a drop in measles vaccination rates between 1989 and 1991. The ages of the patients ranged from 5 to 36 years, with a mean of 14. The researchers discovered wild-type measles virus in brain tissues from individuals with SSPE who had no previous diagnosis of measles and had been vacci...

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