993 resultados para soil differences
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Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.
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This research investigates differences in the stereotype content of immigrant groups between linguistic regions. We expected that immigrant groups who speak the local language of a specific linguistic region would be perceived as more competitive within this region than in another linguistic region. Further, we expected these differences would underlie regional differences in stereotype content, albeit only for the warmth dimension. Predictions were tested in the two largest linguistic regions of Switzerland. As expected, in the German-speaking region, locals perceived German immigrants as more competitive and thus as less warm, whereas in the French-speaking region, locals perceived French immigrants as more competitive and, consequently, as less warm. So, paradoxically, immigrants with strong integration potential are particularly disliked because they are regarded as direct competitors.
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BACKGROUND The possible differences in the disease spectrum and prognosis of HIV infection in women and men is a major point of concern. Women are under-represented in randomized clinical trials and in some cohorts. Discordant results have often been obtained depending on the setting. METHODS We assessed gender differences in clinical and epidemiological features, antiretroviral treatment (ART) exposure and survival in two multicentre cohorts of HIV-positive subjects in Spain: CoRIS-MD and CoRIS. Competing risk regression models were used to assess gender effect on time to start ART and time to first ART change, and a Cox regression model to estimate gender effect on time to death. RESULTS Between January 1996 and December 2008, 1,953 women and 6,072 men naive to ART at study entry were included. The trend analysis over time showed the percentage of women in the younger (<20 years) and older (>50 years) strata increased significantly (P<0.001) from 0.5% and 1.8% in 1996 to 4.9% and 4.2% in 2008, respectively. By competing risk analysis women started ART earlier than men (adjusted subhazard ratio [ASHR] 1.21, 95% CI 1.11, 1.31) in CoRIS cohort, while in CoRIS-MD none of these differences were observed. In both cohorts women showed a shorter time to the first ART change (ASHR 1.10, 95% CI 1.01, 1.19). Pregnancy and patient's/physician's decisions as reasons for changing were more frequent in women than in men in CoRIS. In the Cox regression model, gender was not associated with differences in survival. CONCLUSIONS In two large cohorts in Spain, we observed relevant gender differences in epidemiological characteristics and antiretroviral exposure outcomes, while survival differences were not attributable to gender.
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Genetic crosses in many organisms have shown that alleles of unlinked genes generally assort independently of one another during gamete formation. However, variation in chromosome size may affect the process of meiosis and lead to nonindependent assortment of chromosomes. We therefore examined chromosomes with insertions and found that they preferentially segregated away from the X chromosome during meiosis in Caenorhabditis elegans males. Conversely, chromosomes with deletions preferentially segregated with the X chromosome. The degree of segregation bias was significantly associated with the length of the insertion or deletion. Simulations revealed that this segregation bias leads to genome size reduction in hermaphroditic species, a pattern consistent with differences in genome sizes in the genus Caenorhabditis. These results suggest that insertions and deletions may affect chromosome segregation patterns.
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Time-lapse geophysical data acquired during transient hydrological experiments are being increasingly employed to estimate subsurface hydraulic properties at the field scale. In particular, crosshole ground-penetrating radar (GPR) data, collected while water infiltrates into the subsurface either by natural or artificial means, have been demonstrated in a number of studies to contain valuable information concerning the hydraulic properties of the unsaturated zone. Previous work in this domain has considered a variety of infiltration conditions and different amounts of time-lapse GPR data in the estimation procedure. However, the particular benefits and drawbacks of these different strategies as well as the impact of a variety of key and common assumptions remain unclear. Using a Bayesian Markov-chain-Monte-Carlo stochastic inversion methodology, we examine in this paper the information content of time-lapse zero-offset-profile (ZOP) GPR traveltime data, collected under three different infiltration conditions, for the estimation of van Genuchten-Mualem (VGM) parameters in a layered subsurface medium. Specifically, we systematically analyze synthetic and field GPR data acquired under natural loading and two rates of forced infiltration, and we consider the value of incorporating different amounts of time-lapse measurements into the estimation procedure. Our results confirm that, for all infiltration scenarios considered, the ZOP GPR traveltime data contain important information about subsurface hydraulic properties as a function of depth, with forced infiltration offering the greatest potential for VGM parameter refinement because of the higher stressing of the hydrological system. Considering greater amounts of time-lapse data in the inversion procedure is also found to help refine VGM parameter estimates. Quite importantly, however, inconsistencies observed in the field results point to the strong possibility that posterior uncertainties are being influenced by model structural errors, which in turn underlines the fundamental importance of a systematic analysis of such errors in future related studies.
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The top soil of a 14.5 km(2) region at la Chaux-de-Fonds in the Swiss Jura is exceptionally rich in cadmium. It contains an average of 1.3 mg per kg of soil. The spatial distribution of the metal has no simple pattern that could be explained by atmospheric deposition or agricultural practices. Thin soil contained most of its Cd at the surface; in thicker soil Cd is mainly concentrated between 60 and 80 cm depth. No specific minerals or soil fractions could account for these accumulation, and the vertical distribution of Cd is best explained by leaching from the topsoil and further adsorption within layers of nearly neutral pH. The local Jurassic sedimentary rocks contained too little Cd to account for the Cd concentrations in the soil. Alpine gravels from glacial till were too sparse in soils to explain such a spreading of Cd. Moreover this origin is contradictory with the fact that Cd is concentrated in the sand fraction of soils. The respective distributions of Fe and Cd in soils, and soil fractions, suggested that the spreading of iron nodules accumulated during the siderolithic period (Eocene) was not the main source of Cd. Atmospheric deposition, and spreading of fertiliser or waste from septic tanks seem the only plausible explanation for the Cd concentrations, but at present few factors allow us to differentiate between them.
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This paper compares the procedures of local Brazilian companies (those which have plants in Brazil only) with those of international Brazilian companies (which have plants in at least two countries) regarding the patent management. Although there are a lot more variables to consider when examining the issue of patents in companies, this study presents and analyzes the results of a qualitative research on the decision to patent innovations, the choice of countries where to patent and the strategic significance of patents to the company.
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This study explores the role of early-life education for differences in cognitive functioning between men and women aged 60 and older from seven major urban areas in Latin America and the Caribbean. After documenting statistically significant differences in cognitive functioning between men and women for six of the seven study sites, I assess the extent to which these differences can be explained by prevailing male-female differences in education. I decompose predicted male-female differences in cognitive functioning based on various statistical models for later-life cognition and find robust evidence that male-female differences in education are a major driving force behind cognitive functioning differences between older men and women. This study therefore suggests that early-life differences in educational attainment between boys and girls during childhood have a lasting impact on gender inequity in cognitive functioning at older ages. Increases in educational attainment and the closing of the gender gap in education in many countries in Latin America and the Caribbean may thus result in both higher levels and a more gender-equitable distribution of later-life cognition among the future elderly in those countries.
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Path integration is known to provide information to keep track of spatial location. Surprisingly, few investigations concerning sex differences in computation of the traveling distance have been done. This work was aimed at analyzing the reproduction of both passive and active linear displacements in women and men. To this end, the displacement of blindfolded subjects was done in a wheelchair, then on foot, three times in each condition for a fixed distance. Copies of passive and active traveling distance, distance estimations and pointing responses towards the starting point were analyzed. In passive condition and comparatively to men, women error was larger. Whereas traveling distance was generally underestimated in women, it was overestimated in men. In active condition, no sex differences were observed. When blindfolded subjects have to estimate the traveling distance, the female error was larger than the male one. But, when subjects were asked to indicate the visual cue corresponding to the traveling distance, the male error was larger than the female one. Finally, pointing to the starting point (0°) after a whole-body rotation showed a larger deviation from 0° in men than in women. These results suggest that sex of the subjects influence brain computation of path integration information.
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RÉSUMÉ Il existe dans la pratique de prescription des médicaments de grandes variations entre les hôpitaux. Ces variations sont d'origines multifactorielles, comme par exemple des traditions de prescriptions locales, des considérations pharmato-économiques, la disponibilité d'un médicament, des différences de population, la prévalence d'une maladie, etc. Les études disponibles sur les pratiques de prescription sont souvent réduites à un centre unique, à une région ou à un pays. L'emploi de méthodes et de définitions particulières a jusqu'à pressent limité des comparaisons plus étendues entre les pays et régions. Le but de cette étude est de comparer la pratique de prescription de nouveaux médicaments psychotropes dans des cliniques suisses et allemandes. Cinq hôpitaux psychiatriques ont été sélectionnés, faisant tous partie du projet AMSP, et représentant des cliniques suisses, allemandes, de niveau universitaire ou non. Des données sur 572 patients et 1745 prescriptions ont été collectées durant un jour précis. Les comparaisons ont été ajustées pour l'âge et le sexe. Une différence significative (p <0.001) a été trouvée dans la prescription de nouveaux médicaments antidépresseurs, les cliniciens suisses en donnant en moyenne plus (65.2%) que les allemands (48.3%). Aucune différence significative n'a été démontrée dans la prescription des nouveaux médicaments antipsychotiques atypiques. Il semble en conséquence que les psychiatres suisses ont une propension plus élevée à prescrire des nouveaux médicaments antidépresseurs. Cela semble être dû à des différences de traditions de prescriptions nationales ou régionales. D'autres études sont nécessaires pour investiguer les influences économiques sur la pratique de prescription dans des cliniques suisses et allemandes. SUMMARY Obiective: There are great variations between hospitals in the way drugs are prescribed and these variations may be due to multiple factors such as local prescribing traditions, pharmacoeconomic considerations, drug availability; regional differences of population, disease prevalence etc. Available studies on prescribing habits have, besides studies performed in a unique centre, until now often been restricted to single countries or regions and the comparisons across countries or regions have often been limited by the use of diverse methodologies and definitions. The aim of the present study was to compare drug prescriptions between German and Swiss psychiatric services with regard to their preference of newer psychotropics. Material, method: Five psychiatric hospitals, associated to the AMSP-project, were chosen to represent Swiss and German clinics, university and non-university settings. Data were available from one index day on 572 patients and 1745 prescriptions. The comparisons were adjusted for age and gender. Results: There was a significant difference (p < 0.001) with regard to the prescription of newer antidepressants (NAD), Swiss clinicians giving proportionally more (65.2 %) than the German psychiatrists (48.3 %). No significant difference was, on the other hand, found as to the proportion of atypical antipsychotics, the lack of difference being due to the higher proportion of clozapine among the atypical antipsychotics in Germany. Conclusion: There seems therefore to be a higher propensity for Swiss hospital psychiatrists to prescribe newer antidepressants. This seems to be due to national or regional prescribing traditions. Further studies are needed to investigate the economical influences on antidepressant prescribing in Swiss and German clinics.)
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Plants influence the behavior of and modify community composition of soil-dwelling organisms through the exudation of organic molecules. Given the chemical complexity of the soil matrix, soil-dwelling organisms have evolved the ability to detect and respond to these cues for successful foraging. A key question is how specific these responses are and how they may evolve. Here, we review and discuss the ecology and evolution of chemotaxis of soil nematodes. Soil nematodes are a group of diverse functional and taxonomic types, which may reveal a variety of responses. We predicted that nematodes of different feeding guilds use host-specific cues for chemotaxis. However, the examination of a comprehensive nematode phylogeny revealed that distantly related nematodes, and nematodes from different feeding guilds, can exploit the same signals for positive orientation. Carbon dioxide (CO(2)), which is ubiquitous in soil and indicates biological activity, is widely used as such a cue. The use of the same signals by a variety of species and species groups suggests that parts of the chemo-sensory machinery have remained highly conserved during the radiation of nematodes. However, besides CO(2), many other chemical compounds, belonging to different chemical classes, have been shown to induce chemotaxis in nematodes. Plants surrounded by a complex nematode community, including beneficial entomopathogenic nematodes, plant-parasitic nematodes, as well as microbial feeders, are thus under diffuse selection for producing specific molecules in the rhizosphere that maximize their fitness. However, it is largely unknown how selection may operate and how belowground signaling may evolve. Given the paucity of data for certain groups of nematodes, future work is needed to better understand the evolutionary mechanisms of communication between plant roots and soil biota.