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Results 101 - 150 of 498
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Palace Michael - - 2008
Necromass stocks account for up to 20% of carbon stored in tropical forests and have been estimated to be 14-19% of the annual aboveground carbon flux. Both stocks and fluxes of necromass are infrequently measured. In this study, we directly measured the production of fallen coarse necromass (> or = ...
Wille Martin - - 2008
Animal-like multicellular fossils appeared towards the end of the Precambrian, followed by a rapid increase in the abundance and diversity of fossils during the Early Cambrian period, an event also known as the 'Cambrian explosion'. Changes in the environmental conditions at the Precambrian/Cambrian transition (about 542 Myr ago) have been ...
Shanley James B - - 2008
Stable sulfur (S) isotope ratios can be used to identify the sources of sulfate contributing to streamwater. We collected weekly and high-flow stream samples for S isotopic analysis of sulfate through the entire water year 2003 plus the snowmelt period of 2004. The study area was the 41-ha forested W-9 ...
Chesson Lesley A - - 2008
The stable isotopes of hydrogen, carbon, nitrogen, and oxygen provide insights into a heterotrophic organism's diet and geographic origin. Although the contribution of food delta (2)H and delta (18)O to the final tissue signal will not vary for constrained diets, it will for animals eating varied diets, that is, humans. ...
Gates John B - - 2008
Aerobic conditions in desert aquifers commonly allow high nitrate (NO3-) concentrations in recharge to persist for long periods of time, an important consideration for N-cycling and water quality. In this study, stable isotopes of NO3- (delta15N(NO3) and delta18O(NO3)) were used to trace NO3- cycling processes which affect concentrations in groundwater ...
Budge S M - - 2008
Global warming and the loss of sea ice threaten to alter patterns of productivity in arctic marine ecosystems because of a likely decline in primary productivity by sea ice algae. Estimates of the contribution of ice algae to total primary production range widely, from just 3 to >50%, and the ...
Ghafari Parnian - - 2008
Research on the toxicity of carbon nanotubes has focused on human health risks, and little is known about their impact on natural ecosystems. The ciliated protozoan Tetrahymena thermophila has been widely studied by ecotoxicologists because of its role in the regulation of microbial populations through the ingestion and digestion of ...
Nandy Subir Kumar - - 2008
Bacillus subtilis is known to exhibit cannibalism under nutrient limitation to delay sporulation. Cells of B. subtilis in phosphate buffer solution (PBS) demonstrate an oscillatory behavior in cell number due to cannibalism. Since PBS did not contain any nutrients, the effect of carbon and nitrogen sources on the cannibalistic behavior ...
Goldstein Steven L - - 2008
The Gakkel ridge, which extends under the Arctic ice cap for approximately 1,800 km, is the slowest spreading ocean ridge on Earth. Its spreading created the Eurasian basin, which is isolated from the rest of the oceanic mantle by North America, Eurasia and the Lomonosov ridge. The Gakkel ridge thus ...
Nakano A - - 2008
Four bentonites from various sources were exposed to batch adsorption testing, selective sequential extraction and consolidation tests to investigate their metal retention capacity and hydraulic conductivity for geoenvironmental application such as in clay barrier materials. The Japanese bentonites (JB1-JB3) contain approximately 2-4% of carbonate and trace amount of zeolite (JB2 ...
Ni Hong-Gang - - 2008
A total of 1008 samples were collected from the eight major riverine runoff outlets in the Pearl River Delta (PRD) during 2005-2006 to estimate the fluxes of total organic carbon (TOC) to the coastal ocean off South China. The average dissolved organic carbon (DOC) concentration was 1.67 mg/L with a ...
Soumis Nicolas - - 2008
The dry ice sowing experiment (DISE) consisted in adding dry ice to a lake and monitoring the subsequent evasion of carbon dioxide (CO2). DISE allowed us to evaluate two approaches commonly used for measuring aquatic CO2 diffusive fluxes: the boundary layer equation (BLE) from Cole and Caraco (1998) and a ...
Kelly Jeffrey F - - 2008
A primary constraint on effective conservation of migratory animals is our inability to track individuals through their annual cycle. One such animal is the endangered southwestern subspecies of the Willow Flycatcher, which is difficult to distinguish from conspecifics. Identifying wintering regions used by the endangered subspecies would be an important ...
Larcombe Alexander Neil - - 2008
Seasonal variation in various thermoregulatory, metabolic and ventilatory parameters was examined for southern brown bandicoots (Isoodon obesulus fusciventer) from a Mediterranean climate near Perth, Western Australia. There was significant seasonal variation over the four annual seasons at thermoneutrality (Ta=30 degrees C) in body temperature, oxygen consumption, carbon dioxide production, respiratory ...
Buratti Susanna - - 2008
A glassy carbon electrode coated with cobalt oxide/multi-wall carbon nanotubes (MWCNT) system was used for the detection of carbohydrates and thiols. The modification of the glassy carbon electrode increased the anodic current response of these organic compounds and decreased their overvoltage. The amperometric responses were extremely stable with no loss ...
Scott C - - 2008
Biogeochemical signatures preserved in ancient sedimentary rocks provide clues to the nature and timing of the oxygenation of the Earth's atmosphere. Geochemical data suggest that oxygenation proceeded in two broad steps near the beginning and end of the Proterozoic eon (2,500 to 542 million years ago). The oxidation state of ...
Cuomo R - - 2008
Sweetened carbonated beverages are widely consumed, which has fuelled several conflicting opinions about their effects on upper digestive tract functions. We aimed to evaluate the effect of sweetened carbonated drinks, consumed with a standard meal, on gastro-oesophageal reflux, gastric emptying and gallbladder contraction and postmeal sensations in healthy subjects. Thirteen ...
Luo Wei - - 2008
The present study deals with the degradation of bensulfuron-methyl by microorganisms cultured with different sources of carbon, nitrogen and phosphorus. Addition of carbon source accelerated the degradation of bensulfuron-methyl under co-metabolism process. Sodium lactate was the best carbon source for the degradation of bensulfuron-methyl, compared to other carbon sources studied, ...
Guelinckx, J.
A prerequisite to trace animal movements between two areas using stable isotopes is that food sources of the species under study are isotopically different between both areas. Additionally, for clear interpretation, it is important that the migratory source population is relatively homogeneous in isotopic composition. This preliminary study examined both ...
Ikemoto Tokutaka - - 2008
The present study elucidated the biomagnification profiles of persistent organic pollutants (POPs) through a tropical aquatic food web of Vietnam based on trophic characterization using stable nitrogen analysis. Various biological samples collected from the main stream of the Mekong Delta were provided for the analysis for both POPs, and stable ...
Odabasi Mustafa - - 2008
Sodium hypochlorite (NaOCl) and many organic chemicals contained in household cleaning products may react to generate halogenated volatile organic compounds (VOCs). Halogenated VOC emissions from eight different chlorine bleach containing household products (pure and diluted) were investigated by headspace experiments. Chloroform and carbon tetrachloride were the leading compounds along with ...
Butt Craig M - - 2008
The present study examined spatial trends of perfluoroalkyl compounds (PFCs) in liver samples from 11 populations of ringed seals (Phoca hispida) in the Canadian Arctic from 2002 to 2005. Trophic position and relative carbon sources were compared by analyzing stable nitrogen and carbon isotopes in muscle samples. Geometric mean concentrations ...
Searchinger Timothy - - 2008
Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland ...
Fargione Joseph - - 2008
Increasing energy use, climate change, and carbon dioxide (CO2) emissions from fossil fuels make switching to low-carbon fuels a high priority. Biofuels are a potential low-carbon energy source, but whether biofuels offer carbon savings depends on how they are produced. Converting rainforests, peatlands, savannas, or grasslands to produce food crop-based ...
Law Rachel M - - 2008
Unlike Le Quéré et al. (Reports, 22 June 2007, p. 1735), we do not find a saturating Southern Ocean carbon sink due to recent climate change. In our ocean model, observed wind forcing causes reduced carbon uptake, but heat and freshwater flux forcing cause increased uptake. Our inversions of atmospheric ...
Anastasiadou Sofia - - 2008
A direct plate bioassay procedure was applied for rapid and quantifiable assessment of the influence of various nutritional parameters on pediocin production by Pediococcus acidilactici NRRL B5627. Solid-state cultivation of the microorganism was done on MRS-based media over 3-and 6-hours incubation periods. Nutritional parameters assessed included the carbon source (glucose, ...
Afrane G - - 2008
Coconut shells of West Africa Tall, a local variety of the coconut species Cocos nucifera L., were taken from five different geographical locations in Ghana and examined for the presence and concentration levels of some selected mineral elements using atomic absorption spectrometer. Activated carbons were subsequently made from the shells ...
Moreno, Ana Maria, Biotechnology ...
Bacteria-protozoa interactions are one of the oldest between prokaryotic and eukaryotic organisms. As such, their study offers a unique opportunity to understand the different relationships that have evolved between them, including pathogenesis, and how their interaction can affect some important processes, such as wastewater treatment. In the first part of ...
Simon-Colin C - - 2008
AIMS: The objective of the present work was to describe a new deep-sea, aerobic, mesophilic and heterotrophic bacterium, referenced as strain AT1214, able to produce polyhydroxyalkanoates (PHAs) under laboratory conditions. This bacterium was isolated from a shrimp collected nearby a hydrothermal vent located on the Mid-Atlantic Ridge. METHODS AND RESULTS: ...
Moorhead S Anne - - 2008
The consumption of sugar-sweetened beverages is associated with increased incidence of overweight and obesity, and a factor underlying this putative link could be the relatively low levels of satiety that may be induced by these beverages. Although many sugar-sweetened beverages are carbonated, little attention has been given to the potential ...
Shchepinov Mikhail S - - 2007
A new hypothesis is put forward, linking cellular endurance with dietary consumption of stable heavy isotopes. Due to the isotope effect, biomolecules that incorporate heavier isotopes give rise to more stable molecular structures with increased resistance to damages associated with aging and age-related disease. The inclusion of heavy isotopes might ...
Steffen Will - - 2007
We explore the development of the Anthropocene, the current epoch in which humans and our societies have become a global geophysical force. The Anthropocene began around 1800 with the onset of industrialization, the central feature of which was the enormous expansion in the use of fossil fuels. We use atmospheric ...
Tichomirowa Marion - - 2007
The isotopic composition of air-borne sulphur was investigated in Saxony, Southeast Germany--a region with formerly very high atmospheric SO(2) concentrations. In addition, data from various authors were compiled for different Saxonian locations, spanning from 1992 to 2004, i.e., a time of decreasing SO(2) concentrations in the atmosphere. There were no ...
Ewels Christopher P - - 2007
We present a new computer program able to systematically study chemical addition to and growth or evolution of carbon nanostructures. SACHA is a meta-code able to exploit a wide variety of pre-existing molecular structure codes, automating the otherwise onerous task of constructing, running, and analyzing the large number of input ...
Aberle N - - 2007
Stable isotope signatures of primary producers display high inter- and intraspecific variation. This is assigned to species-specific differences in isotope fractionation and variable abiotic conditions, e.g., temperature, and nutrient and light availability. As consumers reflect the isotopic signature of their food source, such variations have direct impacts on the ecological ...
Ravanelli Maria Ida Bonini - - 2008
Central heme oxigenase-carbon monoxide (HO-CO) pathway has been shown to play a pyretic role in the thermoregulatory response to restraint. However, the specific site in the central nervous system where CO may act modulating this response remains unclear. LC is rich not only in sGC but also in heme oxygenase ...
Müldner Gundula - - 2007
We present the results of stable carbon and nitrogen isotope analysis of bone collagen for 155 individuals buried at the Later Medieval (13th to early 16th century AD) Gilbertine priory of St. Andrew, Fishergate in the city of York (UK). The data show significant variation in the consumption of marine ...
Chen Baozhang - - 2007
Accurate estimation of temporal and spatial variations in photosynthetic discrimination of 13C is critical to carbon cycle research. In this study, a combined ecosystem-boundary layer isotope model, which was satisfactorily validated against intensive campaign data, was used to explore the temporal variability of carbon discrimination in response to environmental driving ...
Firestone R B - - 2007
A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black ...
Yamamoto Naomichi - - 2007
We compared the status of carbonaceous aerosols in Tokyo before and after the implementation of a diesel vehicle regulation intended to reduce the quantity of particulate carbon from diesel engines in one of the largest scale ever attempts at vehicle exhaust control. Radiocarbon (14C) in elemental carbon (EC) and total ...
Pearson D G - - 2007
Although Earth's continental crust is thought to have been derived from the mantle, the timing and mode of crust formation have proven to be elusive issues. The area of preserved crust diminishes markedly with age, and this can be interpreted as being the result of either the progressive accumulation of ...
Crevillén A González - - 2007
Microfluidic devices using carbon nanotube (CNT) materials (single-walled and two multiwalled (MWCNT)) for the analysis of selected analyte groups of significance in foods such as dietary antioxidants, water-soluble vitamins, vanilla flavors, and isoflavones involved in representative food samples have been explored for the first time. Ultrafast separations resulted in well-defined ...
Edgar Kirsty M - - 2007
Major ice sheets were permanently established on Antarctica approximately 34 million years ago, close to the Eocene/Oligocene boundary, at the same time as a permanent deepening of the calcite compensation depth in the world's oceans. Until recently, it was thought that Northern Hemisphere glaciation began much later, between 11 and ...
Egger Garry - - 2007
The obesity epidemic and global warming are linked through energy use. A personal carbon trading scheme aimed at reducing fossil fuel usage could act as a "stealth intervention" for reducing obesity by increasing personal energy use. Such a scheme would complement a corporate "cap and trade" system for carbon emissions, ...
Yeakel Justin D - - 2007
The diets of Australopithecus africanus and Paranthropus robustus are hypothesized to have included C4 plants, such as tropical grasses and sedges, or the tissues of animals which themselves consumed C4 plants. Yet inferences based on the craniodental morphology of A. africanus and P. robustus indicate a seasonal diet governed by ...
Ren Wei - - 2007
Our simulations with the Dynamic Land Ecosystem Model (DLEM) indicate that the combined effect of ozone, climate, carbon dioxide and land use have caused China's grasslands to act as a weak carbon sink during 1961-2000. This combined effect on national grassland net primary productivity (NPP) and carbon storage was small, ...
Anderson O Roger - - 2007
The total carbon contents of gymnamoebae and ciliates, dwelling in the water column of the Hudson Estuary and a highly productive freshwater pond, were monitored during a 7-month period from April through October 2006. The carbon contents of the gymnamoebae and the ciliates were greater in the pond compared with ...
Cherel Yves - - 2007
1. Climatic variation outside the breeding season affects fluctuations in population numbers of seabirds and marine mammals. A challenge in identifying the underlying biological mechanisms is the lack of information on their foraging strategies during winter, when individuals migrate far from their breeding grounds. 2. We investigated the temporal variability ...
Meyzen Christine M - - 2007
It is now well established that oceanic plates sink into the lower mantle at subduction zones, but the reverse process of replacing lost upper-mantle material is not well constrained. Even whether the return flow is strongly localized as narrow upwellings or more broadly distributed remains uncertain. Here we show that ...
Stephens Britton B - - 2007
Measurements of midday vertical atmospheric CO2 distributions reveal annual-mean vertical CO2 gradients that are inconsistent with atmospheric models that estimate a large transfer of terrestrial carbon from tropical to northern latitudes. The three models that most closely reproduce the observed annual-mean vertical CO2 gradients estimate weaker northern uptake of -1.5 ...
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