999 resultados para Bibliographic description
Resumo:
The physical contributions to the KNiF3 magnetic exchange coupling integral have been obtained from specially designed ab initio cluster model calculations. Three important mechanisms have been identified. These are the delocalization of the magnetic orbitals into the anion p band, the variational contribution of the second-order interactions, and the many-body terms hidden in the two-body operator and the Heisenberg Hamiltonian.
Resumo:
AIM: Specific factors responsible for interindividual variability should be identified and their contribution quantified to improve the usefulness of biological monitoring. Among others, age is an easily identifiable determinant, which could play an important impact on biological variability. MATERIALS AND METHODS: A compartmental toxicokinetic model developed in previous studies for a series of metallic and organic compounds was applied to the description of age differences. Young male physiological and metabolic parameters, based on Reference Man information, were taken from preceding studies and were modified to take into account age based on available information about age differences. RESULTS: Numerical simulation using the kinetic model with the modified parameters indicates in some cases important differences due to age. The expected changes are mostly of the order of 10-20%, but differences up to 50% were observed in some cases. CONCLUSION: These differences appear to depend on the chemical and on the biological entity considered. Further work should be done to improve our estimates of these parameters, by considering for example uncertainty and variability in these parameters. [Authors]
Resumo:
Like many states, Iowa faces significant challenges on the energy front. Energy prices have surged in recent years to record levels before declining precipitously following the financial crisis that broke in September 2008. Despite this pullback, the fundamentals that contributed to higher energy prices are expected to return once economies rebound. Oil prices have gone up on increased demand, driven in large part by developing countries such as China and India, whose economies have been rapidly expanding. Natural gas prices have also fluctuated dramatically, trading in a range from $4.50 to $13.00/MMBtu over the past year, but are unlikely to remain at low levels over the long term. As shown in our analysis later on in this report, the difference in levelized cost of electricity from a gas‐fired combined cycle plant can vary significantly depending on the fuel cost. Dependence on others for energy supply involves significant risks and uncertainties. Thus, if Iowa wishes to reduce its dependence on others – or even achieve energy independence – Iowa needs to pursue actions on a numbers of fronts. Following the status quo is not an option. A carbon tax would change the energy landscape in Iowa. Since Iowa is currently 75% dependent on coal, a carbon tax could mean that generators, and in turn ratepayers, could be on the hook for higher electricity prices, though it remains to be seen exactly what the tax scheme will be. In addition to existing plants, a carbon tax would also have a significant impact on the cost of new generation plant. We have modeled carbon taxes ranging from $0‐50/ton in our analysis in the Appendix. However, if a more aggressive carbon policy came into play resulting in market values of for example, $100/ton or even $200/ton, then that could raise the cost of coal‐ and gas‐fired generation significantly, making alternatives such as wind more economical.
Resumo:
Inflammatory bowel diseases are a result of an aberrant mucosal immune response to gut microflora. Several groups have reported newly diagnosed inflammatory bowel diseases following solid organ transplantation and subsequent immunosuppressive therapy. We describe four cases of newly diagnosed inflammatory bowel diseases following liver transplantation in a pool of 120 transplanted patients. These patients had no prior history of inflammatory bowel diseases or primary sclerosing cholangitis and were immunosuppressed. Two patients were transplanted for a hepatitis C related cirrhosis, one for alcoholic cirrhosis and one patient for autoimmune cirrhosis. Three patients were diagnosed with ulcerative colitis and one with Crohn's disease. These four patients were on a cyclosporin monotherapy when their inflammatory bowel diseases were diagnosed. These data suggest that cyclosporin monotherapy following solid organ transplantation does not prevent development of inflammatory bowel diseases.
Resumo:
In August 2008, reactivation of the Little Salmon Lake landslide occurred. During this event, hundreds of conical mounds of variable size and composition formed in the deposition zone. The characteristics of these landforms are described and a potential mechanism for their formation is proposed. A preliminary slope stability analysis of the 2007 Mount Steele rock and ice avalanche was also undertaken. The orientation of very high persistence (>20 m long) structural planes (e.g., faults, joints and bedding) within bedrock in the source zone was obtained using an airborne-LiDAR digital elevation model and the software COLTOP-3D. Using these discontinuity orientation measurements, kinematic, surface wedge and simple three-dimensional distinct element slope stability analyses were performed.
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This paper describes a new species of arcturidean isopod, Arcturella poorei, from the Atlantic seaboard of Cadiz (Spain). A diagnosis and description of the species is presented, and a comparison with other species of the genus from the area.
Resumo:
The objective of this work was to evaluate the width and length incidence in a single seed fraction of oat [Avena sativa (L.)] cv. Cristal. The seeds were selected by a mechanical divider and by hand, and their correspondence to radiographic images in seeds with glumes and their caryopses. The width and length of the seeds with glumes and their caryopses were measured with electronic calliper, and their weight, with precision balance. Radiographic images of seeds with glumes were taken with an X-ray experimental equipment. The analyst selected seeds with glumes by the width and by the length previously determined and so with more weight, than that obtained by hand selection was slightly narrower, larger and lighter. The presence of the glumes masked the caryopses real dimensions (width and length), and conduced the analyst to select seeds that differed more by the width than by the length. The radiographic images showed the presence, or not, of caryopses inside the seed and its real dimensions. The mechanical partition method for seeds showed to be more efficient because the analyst subjectivity was not considered when the selection upon its dimensions was done. The X-ray analysis was a useful tool that complements the pure seed fraction selection as another factor of seed quality.