life cycle – Page 2 – Shamskm: A site to exchange knowledge and solutions

Melting Sea Ice Threatens Emperor Penguins, Study Finds

By Guest PostJuly 1, 2012Environment, Natureantarctic peninsula, antarctic sea ice, Antarctica, christophe barbraud, climate models, climate variable, demographic model, dion islets, east antarctica, emperor penguins, food web, global temperature, happy feet, henri weimerskirch, ipev, krill, life cycle, marika holland, mark serreze, melting sea ice, nutrient cycle, organism, penguin colony, penguin population, sea bird, sea ice forecasts, shrimplike animal, squid, stephanie jenouvrier, terre adelie, warming temperature, whoi

At nearly four feet tall, the Emperor penguin is Antarctica’s largest sea bird—and thanks to films like “March of the Penguins” and “Happy Feet,” it’s also one of the continent’s most iconic. If global temperatures continue to rise, however, the Emperor penguins in Terre Adélie, in East Antarctica may eventually disappear, according to a new study by led by researchers from the Woods Hole Oceanographic Institution (WHOI). The study was published in the June 20th edition of the journal Global Change Biology.

“Over the last century, we have already observed the disappearance of the Dion Islets penguin colony, close to the West Antarctic Peninsula,” says Stephanie Jenouvrier, WHOI biologist and lead author of the new study. “In 1948 and the 1970s, scientists recorded more than 150 breeding pairs there. By 1999, the population was down to just 20 pairs, and in 2009, it had vanished entirely.” Like in Terre Adélie, Jenouvrier thinks the decline of those penguins might be connected to a simultaneous decline in Antarctic sea ice due to warming temperatures in the region. (more…)

Early Spring Drives Butterfly Population Declines

By Guest PostMarch 18, 2012Environment, Naturebutterfly population, carol boggs, caterpillars, climate change, colorado rocky mountains, david inouye, flower, life cycle, mormon fritillary butterfly, national science foundation, nectar, population, saran twombly, snowmelt, species, speyeria mormonia, university of maryland

“Ahead-of-time” snowmelt triggers chains of events in the Mormon Fritillary butterfly

Early snowmelt caused by climate change in the Colorado Rocky Mountains snowballs into two chains of events: a decrease in the number of flowers, which, in turn, decreases available nectar. The result is decline in a population of the Mormon Fritillary butterfly, Speyeria mormonia.

Using long-term data on date of snowmelt, butterfly population sizes and flower numbers at the Rocky Mountain Biological Laboratory, Carol Boggs, a biologist at Stanford University, and colleagues uncovered multiple effects of early snowmelt on the growth rate of an insect population. (more…)

Researchers Suggest A Proximate Cause of Cancer

By Guest PostJanuary 26, 2012Health, Science3d cancer model, biochemical carcinogenic factors, biochemical factors, boston university, cancer cells, cancer progression, cancerous behavior, carcinogenic factors, cell, computational model, Environment, genetic, healthy tissue, life cycle, malignant tumor, mechanical factors, mechanical property, muhammad zaman, multiplication rate, parag katira, physical stress, prevent cancer, probability of death, radiation, roger t bonnecaze, softening of cells, stiffer cells, synthetic chemicals, types of cancers, understanding of cancer, university of texas at austin

AUSTIN, TX — Researchers from The University of Texas at Austin’s Department of Chemical Engineering are the first to show that mechanical property changes in cells may be responsible for cancer progression — a discovery that could pave the way for new approaches to predict, treat and prevent cancer.

Postdoctoral student Parag Katira and his adviser, Roger T. Bonnecaze, department chair in the Cockrell School of Engineering and T. Brockett Hudson Professor, worked with Muhammad Zaman of Boston University to devise a 3-D cancer model that shows the softening of cells and changes in cell binding cause cancerous behavior in cells. These mechanical property changes cause cells to divide uncontrollably — making them less likely to die and resulting in malignant tumor growth. The findings present a unique physics-based perspective on understanding cancer progression and were published recently in the American Physical Society’s journal Physical Review Letters. (more…)

Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar

By Guest PostNovember 5, 2010Scienceastronomer, black hole, dead quasar, dutch, Galaxy, galaxy zoo, gas cloud, hanny van arkel, hanny's object, hanny's voorwerp, kevin schawinski, life cycle, light echo, meg urry, paolo coppi, priyamvada natarajan, schoolteacher, yale university

The green Voorwerp in the foreground remains illuminated by light emitted up to 70,000 years ago by a quasar in the center of the background galaxy, which has since died out. Image credit: WIYN/William Keel/Anna Manning

While sorting through hundreds of galaxy images as part of the Galaxy Zoo citizen science project two years ago, Dutch schoolteacher and volunteer astronomer Hanny van Arkel stumbled upon a strange-looking object that baffled professional astronomers. Two years later, a team led by Yale University researchers has discovered that the unique object represents a snapshot in time that reveals surprising clues about the life cycle of black holes.

In a new study, the team has confirmed that the unusual object, known as Hanny’s Voorwerp (Hanny’s “object” in Dutch), is a large cloud of glowing gas illuminated by the light from a quasar-an extremely energetic galaxy with a supermassive black hole at its center. The twist, described online in the Astrophysical Journal Letters, is that the quasar lighting up the gas has since burned out almost entirely, even though the light it emitted in the past continues to travel through space, illuminating the gas cloud and producing a sort of “light echo” of the dead quasar. (more…)

Tag Archives: life cycle

Melting Sea Ice Threatens Emperor Penguins, Study Finds

Early Spring Drives Butterfly Population Declines

Researchers Suggest A Proximate Cause of Cancer

Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar