Montag, 28. März 2011

Science Review March 2011 / Neues aus der Wissenschaft 2011 (en)

Here is this Months overview of Science News, this time due to time constraints only via ScienceDaily:

Anthropology, Hunter/Gatherers:

"That human evolution follows a progressive trajectory is one of the most deeply-entrenched assumptions about our species. .... But is this assumption correct? Were the earliest humans significantly different from us? In a paper published in the latest issue of Current Anthropology, archaeologist John Shea (Stony Brook University) shows they were not. ... Shea argues that comparing the behavior of our most ancient ancestors to Upper Paleolithic Europeans holistically and ranking them in terms of their "behavioral modernity" is a waste of time. There are no such things as modern humans, Shea argues, just Homo sapiens populations with a wide range of behavioral variability."  (via Science Daily)

"Research findings published in the March 11 edition of the journal Science by an international team of noted anthropologists, ... who study hunter-gatherer societies, are informing the issue by suggesting that human ancestral social structure may be the root of cumulative culture and cooperation and, ultimately, human uniqueness. Because humans lived as hunter-gatherers for 95 percent of their species' history, current foraging societies provide the best window for viewing human social evolution, according to the authors..... Their findings identify human hunter-gatherer group structure as unique among primates.....A major point in the study is that foraging bands contain several individuals completely unconnected by kinship or marriage ties, yet include males with a vested interest in the offspring of daughters, sisters and wives. This organization mitigates the group hostility frequently seen in other apes and also promotes interaction among residential groups, thereby leading to the development of a large social network....... the unique composition of human ancestral groups promotes cooperation among large groups of non-kin, something extremely rare in nature." (via Science Daily)

"Societies where material wealth is most valued are therefore the most unequal, said Monique Borgerhoff Mulder, the UC Davis anthropology professor...The researchers also showed that levels of inequality are influenced both by the types of wealth important to a society and the governing rules and regulations. Hunter-gatherers rely on their wits, social connections and strength to make a living. In these economies, wealth inheritance is modest because wits and social connections can be transferred only to a certain degree. The level of economic inequality in hunter-gatherer societies is on a par with the most egalitarian modern democratic economies...."An interesting implication of this is that the Internet Age will not necessarily assure equality, .... Whether the greater importance of networks and knowledge... will weaken the link between parental and next-generation wealth, and thus provide opportunities for a more egalitarian society, will depend on the institutions and norms prevailing in a society," she said." (via Science Daily)

"The Baylor study found that pre-European so-called "natural" floodplains [in the US] have a history of prehistoric indigenous land use, and thus colonial-era Europeans were not the first people to have an impact on the hydrologic systems of eastern North America. The study also found that prehistoric small-scale agricultural societies caused widespread ecological change and increased sedimentation ..."The findings conclusively demonstrate that Native Americans in eastern North America impacted their environment well before the arrival of Europeans. Through their agricultural practices, Native Americans increased soil erosion and sediment yields to the Delaware River basin."
The Baylor researchers found that prehistoric people decreased forest cover to reorient their settlements and intensify corn production."..."This study provides some of the most significant evidence yet that Native Americans impacted the land to a much greater degree than previously thought" " (via Science Daily)

Alternative Horticulture:

"...University of Illinois used evidence from more than 80 forest sites in six tropical countries to test how local participation affects social and ecological benefits from forests.
The social benefits include access to forest products that households rely on for their subsistence, such as firewood, fodder for livestock and timber for housing. The main ecological benefit is higher biodiversity in the tropical forests. The team's results were published on March 25 in the journal Science." (via Science Daily)

"Agricultural Research Service (ARS) hydrologist John Williams led a study that compared runoff, soil erosion and crop yields in a conventional, intensively tilled winter wheat-fallow system and a no-till 4-year cropping rotation system. ...No-till production left the soil surface intact and protected pore space beneath the soil surface, which allowed more water to infiltrate into the subsoil. In addition, there was no significant yield difference between the no-till and conventional till production, and direct seeding in no-till production saved fuel and time" (via Science Daily)

Ecosystems and Climate:

"We've identified that the boreal forest, particularly in Siberia, is converting from predominantly needle-shedding larch trees to evergreen conifers in response to warming climate," said the study's lead author, Jacquelyn Shuman, a post-doctoral research associate in environmental sciences in University of Virginia's Graduate School of Arts & Sciences. "This will promote additional warming and vegetation change, particularly in areas with low species diversity." (via Science Daily)

"Loss of Plant Diversity Threatens Earth's Life-Support Systems...."The idea that declining diversity compromises the functioning of ecosystems was controversial for many years,...[t]his paper should be the final nail in the coffin of that controversy. It's the most rigorous and comprehensive analysis yet, and it clearly shows that extinction of plant species compromises the productivity that supports Earth's ecosystems.".....The analysis also suggests, based on laboratory studies of algae, that diverse plant communities generate oxygen -- and take-up carbon dioxide -- more than twice as fast as plant monocultures....."Species extinction is happening now, and it's happening quickly. ...[w]e risk crossing a threshold that we can't come back from." " (via Science Daily)

"The 2011 Arctic sea ice extent maximum that marks the beginning of the melt season appears to be tied for the lowest ever measured by satellites, say scientists at the University of Colorado Boulder's National Snow and Ice Data Center."  (via Science Daily)

""[T]he sixth mass extinction could arrive within as little as 3 to 22 centuries,"..."So far, only 1 to 2 percent of all species have gone extinct in the groups we can look at clearly,...."Even though the magnitude is fairly low, present rates [of extinction] are higher than during most past mass extinctions."...."It looks like modern extinction rates resemble mass extinction rates, even after setting a high bar for defining 'mass extinction,'" Barnosky said." (via Science Daily)

"Green" Technologies, Lifestyle:

""There is enormous interest in using carbon dioxide to make hydrocarbon fuels,...we can use the same infrastructure to process and transport this new hydrocarbon fuel that we use for fossil fuels."...using a photosynthetic bacterium and a hydrocarbon-producing bacterium together to make hydrocarbons from carbon dioxide."  (via Science Daily)

"Overall the survey, which will follow 40,000 UK households over many years, found that 60% of people believed that a major environmental disaster is pending if things continue on their current course....
Nonetheless, people's willingness to behave in an environmentally-friendly way comes with conditions as 59% of those surveyed agreed that 'any changes I make to help the environment need to fit in with my lifestyle' .... employed people seem less likely to adopt pro-environmental behaviours...." (via Science Daily)

"TU Delft has demonstrated that the speed at which inexpensive solar cells are produced can be increased by a factor of ten -- and that this can be achieved without any detriment to the energy yield of the cells. This will almost certainly result in a further reduction in the price of the cells, which are made of amorphous silicon."  (via Science Daily)

"...The high-tech and environmentally friendly model fish farms ... are based on water recirculation technology. This means that the fish farm recycles as much as 95 percent of the water instead of merely letting it drain away into the countryside.
Now DTU Aqua and several of the key players in the industry are joining forces to take Danish fish farming a stage further. In order to put large rainbow trout and salmon on the menu as well, the so-called model fish farms are to be expanded to include the breeding of saltwater fish as well as freshwater fish -- and it is to take place inland. " (via Science Daily)