996 resultados para Kabata-Pendias, Alina: Trace elements from soil to human


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This paper examines the most productive authors, institutions and countries in regional and urban science from 1991 to 2000 using information on published articles (and pages) from a sample of widely recognized journals in this field: ARS, JUE, JRS, IJURR, IRSR, PRS, RSUE, RS and US. We also consider the relation between the country of the institution named in articles and the country in which the journal is published, in order to know if there are a home publication bias in regional and urban science. Analysis was made for the whole decade and by subperiods, this allowed us to make a more dynamic interpretation of the results

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We investigate the spreading of 4He droplets on alkali-metal surfaces at zero temperature, within the frame of finite range density-functional theory. The equilibrium configurations of several 4HeN clusters and their asymptotic trend with increasing particle number N, which can be traced to the wetting behavior of the quantum fluid, are examined for nanoscopic droplets. We discuss the size effects inferring that the asymptotic properties of large droplets correspond to those of the prewetting film.

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We present a numerical and partially analytical study of classical particles obeying a Langevin equation that describes diffusion on a surface modeled by a two-dimensional potential. The potential may be either periodic or random. Depending on the potential and the damping, we observe superdiffusion, large-step diffusion, diffusion, and subdiffusion. Superdiffusive behavior is associated with low damping and is in most cases transient, albeit often long. Subdiffusive behavior is associated with highly damped particles in random potentials. In some cases subdiffusive behavior persists over our entire simulation and may be characterized as metastable. In any case, we stress that this rich variety of behaviors emerges naturally from an ordinary Langevin equation for a system described by ordinary canonical Maxwell-Boltzmann statistics.

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We study the forced displacement of a thin film of fluid in contact with vertical and inclined substrates of different wetting properties, that range from hydrophilic to hydrophobic, using the lattice-Boltzmann method. We study the stability and pattern formation of the contact line in the hydrophilic and superhydrophobic regimes, which correspond to wedge-shaped and nose-shaped fronts, respectively. We find that contact lines are considerably more stable for hydrophilic substrates and small inclination angles. The qualitative behavior of the front in the linear regime remains independent of the wetting properties of the substrate as a single dispersion relation describes the stability of both wedges and noses. Nonlinear patterns show a clear dependence on wetting properties and substrate inclination angle. The effect is quantified in terms of the pattern growth rate, which vanishes for the sawtooth pattern and is finite for the finger pattern. Sawtooth shaped patterns are observed for hydrophilic substrates and low inclination angles, while finger-shaped patterns arise for hydrophobic substrates and large inclination angles. Finger dynamics show a transient in which neighboring fingers interact, followed by a steady state where each finger grows independently.

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AIM: To study the development of motor speed and associated movements in participants aged 5 to 18 years for age, sex, and laterality. METHOD: Ten motor tasks of the Zurich Neuromotor Assessment (repetitive and alternating movements of hands and feet, repetitive and sequential finger movements, the pegboard, static and dynamic balance, diadochokinesis) were administered to 593 right-handed participants (286 males, 307 females). RESULTS: A strong improvement with age was observed in motor speed from age 5 to 10, followed by a levelling-off between 12 and 18 years. Simple tasks and the pegboard matured early and complex tasks later. Simple tasks showed no associated movements beyond early childhood; in complex tasks associated movements persisted until early adulthood. The two sexes differed only marginally in speed, but markedly in associated movements. A significant laterality (p<0.001) in speed was found for all tasks except for static balance; the pegboard was most lateralized, and sequential finger movements least. Associated movements were lateralized only for a few complex tasks. We also noted a substantial interindividual variability. INTERPRETATION: Motor speed and associated movements improve strongly in childhood, weakly in adolescence, and are both of developmental relevance. Because they correlate weakly, they provide complementary information.

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Plasmodium sporozoites make a remarkable journey from the mosquito midgut to the mammalian liver. The sporozoite's major surface protein, circumsporozoite protein (CSP), is a multifunctional protein required for sporozoite development and likely mediates several steps of this journey. In this study, we show that CSP has two conformational states, an adhesive conformation in which the C-terminal cell-adhesive domain is exposed and a nonadhesive conformation in which the N terminus masks this domain. We demonstrate that the cell-adhesive domain functions in sporozoite development and hepatocyte invasion. Between these two events, the sporozoite must travel from the mosquito midgut to the mammalian liver, and N-terminal masking of the cell-adhesive domain maintains the sporozoite in a migratory state. In the mammalian host, proteolytic cleavage of CSP regulates the switch to an adhesive conformation, and the highly conserved region I plays a critical role in this process. If the CSP domain architecture is altered such that the cell-adhesive domain is constitutively exposed, the majority of sporozoites do not reach their target organs, and in the mammalian host, they initiate a blood stage infection directly from the inoculation site. These data provide structure-function information relevant to malaria vaccine development.

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In this paper, we have presented results on silicon thin films deposited by hot-wire CVD at low substrate temperatures (200 °C). Films ranging from amorphous to nanocrystalline were obtained by varying the filament temperature from 1500 to 1800 °C. A crystalline fraction of 50% was obtained for the sample deposited at 1700 °C. The results obtained seemed to indicate that atomic hydrogen plays a leading role in the obtaining of nanocrystalline silicon. The optoelectronic properties of the amorphous material obtained in these conditions are slightly poorer than the ones observed in device-grade films grown by plasma-enhanced CVD due to a higher hydrogen incorporation (13%).

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Convictions statistics were the first criminal statistics available in Europe during the nineteenth century. Their main weaknesses as crime measures and for comparative purposes were identified by Alphonse de Candolle in the 1830s. Currently, they are seldom used by comparative criminologists, although they provide a less valid but more reliable measure of crime and formal social control than police statistics. This article uses conviction statistics, compiled from the four editions of the European Sourcebook of Crime and Criminal Justice Statistics, to study the evolution of persons convicted in European countries from 1990 to 2006. Trends in persons convicted for six offences -intentional homicide, assault, rape, robbery, theft, and drug offences- and up to 26 European countries are analysed. These trends are established for the whole of Europe as well as for a cluster of Western European countries and a cluster of Central and Eastern European countries. The analyses show similarities between both regions of Europe at the beginning and at the end of the period under study. After a general increase of the rate of persons convicted in the early 1990s in the whole of Europe, trends followed different directions in Western and in Central and Eastern Europe. However, during the 2000s, it can be observed, throughout Europe, a certain stability of the rates of persons convicted for intentional homicides, accompanied by a general decrease of the rate of persons convicted for property offences, and an increase of the rate of those convicted for drug offences. The latter goes together with an increase of the rate of persons convicted for non lethal violent offences, which only reached some stability at the end of the time series. These trends show that there is no general crime drop in Europe. After a discussion of possible theoretical explanations, a multifactor model, inspired by opportunity-based theories, is proposed to explain the trends observed.

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HIV-infected individuals may have accelerated atherogenesis and an increased risk for premature coronary artery disease. Dyslipidemia represents a key pro-atherogenic mechanism. In HIV-infected patients, dyslipidemia is typically attributed to the adverse effects of antiretroviral therapy. Nine recent genome-wide association studies have afforded a comprehensive, unbiased inventory of common SNPs at 36 genetic loci that are reproducibly associated with dyslipidemia in the general population. Genome-wide association study-validated SNPs have now been demonstrated to contribute to dyslipidemia in the setting of HIV infection and antiretroviral therapy. In a Swiss HIV-infected study population, a similar proportion of serum lipid variability was explained by antiretroviral therapy and by genetic background. In the individual patient, both antiretroviral therapy and the cumulative effect of SNPs contribute to the risk of high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol and hypertriglyceridemia. Genetic variants presumably contribute to additional major metabolic complications in HIV-infected individuals, including diabetes mellitus and coronary artery disease. In an effort to explain an increasing proportion of the heritability of complex metabolic traits, ongoing large-scale gene resequencing studies are focusing on the effects of rare SNPs and structural genetic variants.

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CoFe-AgCu granular films of compositions ranging from 0.17-0.44 ferromagnetic atomic concentration were prepared by rf sputtering. The microstructure and the transport and magnetic properties suggested that this family of samples can be classified into two groups with a crossover concentration at about 32 at. %. The experimental results for samples Co34Fe8Ag54Cu4 and Co18Fe8Ag70Cu4, which are representative of both different behaviors, are discussed. For the as-prepared sample with higher CoFe content, an uncompensated out-of-plane antiferromagneticlike microstructure with dominant demagnetizing interactions was observed. The particle growth through the annealing led to large in-plane ferromagneticlike clusters with dominant magnetizing interactions. The thermal dependence of the remanence-to-saturation ratio of the as-prepared and annealed samples indicated the existence of a high degree of magnetic correlations leading to a very low magnetoresistivity: In none of the cases was a Stoner¿Wohlfarth behavior observed. On the contrary, for the sample with lower CoFe content, the magnetoresistivity change was much higher, and the remanence followed the expected behavior, since magnetic correlations were strongly reduced through dilution.

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We study the forced displacement of a thin film of fluid in contact with vertical and inclined substrates of different wetting properties, that range from hydrophilic to hydrophobic, using the lattice-Boltzmann method. We study the stability and pattern formation of the contact line in the hydrophilic and superhydrophobic regimes, which correspond to wedge-shaped and nose-shaped fronts, respectively. We find that contact lines are considerably more stable for hydrophilic substrates and small inclination angles. The qualitative behavior of the front in the linear regime remains independent of the wetting properties of the substrate as a single dispersion relation describes the stability of both wedges and noses. Nonlinear patterns show a clear dependence on wetting properties and substrate inclination angle. The effect is quantified in terms of the pattern growth rate, which vanishes for the sawtooth pattern and is finite for the finger pattern. Sawtooth shaped patterns are observed for hydrophilic substrates and low inclination angles, while finger-shaped patterns arise for hydrophobic substrates and large inclination angles. Finger dynamics show a transient in which neighboring fingers interact, followed by a steady state where each finger grows independently.

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As a hallmark of tuberculosis (TB), Mycobacterium tuberculosis (MTB) induces granulomatous lung lesions and systemic inflammatory responses during active disease. Molecular regulation of inflammation is associated with inflammasome assembly. We determined the extent to which MTB triggers inflammasome activation and how this impacts on the severity of TB in a mouse model. MTB stimulated release of mature IL-1β in macrophages while attenuated M. bovis BCG failed to do so. Tubercle bacilli specifically activated the NLRP3 inflammasome and this propensity was strictly controlled by the virulence-associated RD1 locus of MTB. However, Nlrp3-deficient mice controlled pulmonary TB, a feature correlated with NLRP3-independent production of IL-1β in infected lungs. Our studies demonstrate that MTB activates the NLRP3 inflammasome in macrophages in an ESX-1-dependent manner. However, during TB, MTB promotes NLRP3- and caspase-1-independent IL-1β release in myeloid cells recruited to lung parenchyma and thus overcomes NLRP3 deficiency in vivo in experimental models.