890 resultados para Disentangling fragmentation processes and edge effects


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This double-blind placebo-controlled study was designed to investigate the acute and sustained hormonal, renal hemodynamic, and tubular effects of concomitant ACE and neutral endopeptidase (NEP) inhibition by omapatrilat, a vasopeptidase inhibitor, in men. Thirty-two normotensive subjects were randomized to receive a placebo, omapatrilat (40 or 80 mg), or the fosinopril/hydrochlorothiazide (FOS/HCTZ; 20 and 12.5 mg, respectively) fixed combination for 1 week. Blood pressure, renal hemodynamics, urinary electrolytes and atrial natriuretic peptide excretion, and several components of the renin-angiotensin system were measured for 6 hours on days 1 and 7 of drug administration. When compared with the placebo and the FOS/HCTZ combination, omapatrilat induced a significant decrease in plasma angiotensin II levels (P<0.001 versus placebo; P<0.05 versus FOS/HCTZ) and an increase in urinary atrial natriuretic peptide excretion (P<0.01). These hormonal effects were associated with a significant fall in blood pressure (P<0.01) and a marked renal vasodilatation, but with no significant changes in glomerular filtration rate. The FOS/HCTZ markedly increased urinary sodium excretion (P<0.001). The acute natriuretic response to FOS/HCTZ was significantly greater than that observed with omapatrilat (P<0.01). Over 1 week, however, the cumulative sodium excretion induced by both doses of omapatrilat (P<0.01 versus placebo) was at least as great as that induced by the dose of FOS/HCTZ (P=NS versus FOS/HCTZ). In conclusion, the results of the present study in normal subjects demonstrate that omapatrilat has favorable renal hemodynamic effects. Omapatrilat combines potent ACE inhibition with a sustained natriuresis, which explains its well-documented potent antihypertensive efficacy.

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Youth is one of the phases in the life-cycle when some of the most decisivelife transitions take place. Entering the labour market or leaving parentalhome are events with important consequences for the economic well-beingof young adults. In this paper, the interrelationship between employment,residential emancipation and poverty dynamics is studied for eight Europeancountries by means of an econometric model with feedback effects. Resultsshow that youth poverty genuine state dependence is positive and highly significant.Evidence proves there is a strong causal effect between poverty andleaving home in Scandinavian countries, however, time in economic hardshipdoes not last long. In Southern Europe, instead, youth tend to leave theirparental home much later in order to avoid falling into a poverty state that ismore persistent. Past poverty has negative consequences on the likelihood ofemployment.

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This paper proposes a framework to examine business ethical dilemmas andbusiness attitudes towards such dilemmas. Business ethical dilemmas canbe understood as reflecting a contradiction between a socially detrimentalprocess and a self-interested profitable consequence. This representationallows us to distinguish two forms of behavior differing by whetherpriority is put on consequences or on processes. We argue that theseforms imply very different business attitudes towards society:controversial or competitive for the former and aligned or cooperativefor the latter. These attitudes are then analyzed at the discursive level in order to address the question of good faith in businessargumentation, i.e. to which extent are these attitudes consistent withactual business behaviors. We argue that consequential attitudes mostlyinvolve communication and lobbying actions aiming at eluding the dilemma.Therefore, the question of good faith for consequential attitudes liesin the consistency between beliefs and discourse. On the other hand,procedural attitudes acknowledge the dilemma and claim a change of theprocess of behavior. They thus raise the question of the consistencybetween discourses and actual behavior. We apply this processes/consequencesframework to the case of the oil industry s climate change ethical dilemmawhich comes forth as a dilemma between emitting greenhouse gases and making more profits . And we examine the different attitudes of two oilcorporations-BP Amoco and ExxonMobil-towards the dilemma.

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In 2007 the first Quality Enhancement Meeting on sampling in the European SocialSurvey (ESS) took place. The discussion focused on design effects and inteviewereffects in face-to-face interviews. Following the recomendations of this meeting theSpanish ESS team studied the impact of interviewers as a new element in the designeffect in the response s variance using the information of the correspondent SampleDesign Data Files. Hierarchical multilevel and cross-classified multilevel analysis areconducted in order to estimate the amount of responses variation due to PSU and tointerviewers for different questions in the survey. Factor such as the age of theinterviewer, gender, workload, training and experience and respondent characteristicssuch as age, gender, renuance to participate and their possible interactions are alsoincluded in the analysis of some specific questions like trust in politicians and trustin legal system . Some recomendations related to future sampling designs and thecontents of the briefing sessions are derived from this initial research.

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This paper proposes a common and tractable framework for analyzingdifferent definitions of fixed and random effects in a contant-slopevariable-intercept model. It is shown that, regardless of whethereffects (i) are treated as parameters or as an error term, (ii) areestimated in different stages of a hierarchical model, or whether (iii)correlation between effects and regressors is allowed, when the sameinformation on effects is introduced into all estimation methods, theresulting slope estimator is also the same across methods. If differentmethods produce different results, it is ultimately because differentinformation is being used for each methods.

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Carbon and oxygen isotope studies of the host and gangue carbonates of Mississippi Valley-type zinc-lead deposits in the San Vicente District hosted in the Upper Triassic to Lower Jurassic dolostones of the Pucara basin (central Peru) were used to constrain models of the ore formation. A mixing model between an incoming hot saline slightly acidic radiogenic (Pb, Sr) fluid and the native formation water explains the overall isotopic variation (delta(13)C = - 11.5 to + 2.5 parts per thousand relative to PDB and delta(18)O = + 18.0 to + 24.3 parts per thousand relative to SMOW) of the carbonate generations. The dolomites formed during the main ore stage show a narrower range (delta(13)C = - 0.1 to + 1.7 parts per thousand and delta(18)O = + 18.7 to + 23.4 parts per thousand) which is explained by exchange between the mineralizing fluids and the host carbonates combined with changes in temperature and pressure. This model of fluid-rock interaction explains the pervasive alteration of the host dolomite I and precipitation of sphalerite I. The open-space filling hydrothermal white sparry dolomite and the coexisting sphalerite II formed by prolonged fluid-host dolomite interaction and limited CO2 degassing. Late void-filling dolomite III (or calcite) and the associated sphalerite III formed as the consequence of CO2 degassing and concomitant pH increase of a slightly acidic ore fluid. Widespread brecciation is associated to CO2 outgassing. Consequently, pressure variability plays a major role in the ore precipitation during the late hydrothermal events in San Vicente. The presence of native sulfur associated with extremely carbon-light calcites replacing evaporitic sulfates (e.g., delta(13)C = - 11.5 parts per thousand), altered native organic matter and heavier hydrothermal bitumen (from - 27.0 to - 23.0 parts per thousand delta(13)C) points to thermochemical reduction of sulfate and/or thiosulfate. The delta(13)C- and delta(18)O-values of the altered host dolostone and hydrothermal carbonates, and the carbon isotope composition of the associated organic matter show a strong regional homogeneity. These results coupled with the strong mineralogical and petrographic similarities of the different MVT occurrences perhaps reflects the fact that the mineralizing processes were similar in the whole San Vicente belt, suggesting the existence of a common regional mineralizing hydrothermal system with interconnected plumbing.

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Variation in coloration with a strong underlying genetic basis is frequently found within animal populations but little is known about its function. Covariation between colour polymorphism and life-history traits can arise because morphs perform differently among environments or because they possess alternative alleles coding for key life-history traits. To test these two hypotheses, we studied a population of tawny owls Strix aluco, a bird displaying red, brown and grey morphs. We assessed the colour morph of breeding females, swapped eggs or hatchlings between pairs of nests, and examined how body condition in 3-week-old nestlings covaries with coloration of foster and genetic mothers. Redder foster and genetic mothers produced young in better condition. Because in two other years we observed that greyish females produced offspring in better condition than those of red females, the present study suggests that colour polymorphism signals genetic and phenotypic adaptations to cope with a fluctuating environment.

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This paper summarizes data on the factors involved in addiction and dependence to cigarettes. Nicotine has been intensively studied by the tobacco industry, for instance for its addictive effect at the lowest possible rates. The addition of diammonium phosphate and urea produces an alcalinization of the pH of cigarette smoke, and promotes the absorption and the trans-membrane passage of nicotine. The taste, the smell of smoke, and the visual aspect of the pack of cigarettes are also sensory components that promote addiction. Finally, menthol, sugar, cocoa and liquorice added to cigarettes also play a role in dependence and addiction to cigarettes by, for instance, making an anesthetic effect on the airways.

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OBJECTIVE: To assess the thermogenic response of dopamine at three different infusion rates and to analyze its effects on various biochemical variables. DESIGN: Randomized sequential experimental treatment bracketed by control periods. PATIENTS: Eight young healthy male volunteers with normal body weight (51 to 89 kg). INTERVENTIONS: Three experimental periods during which dopamine was administered iv in a randomized order at rates of 2.5, 5, or 10 micrograms/kg.min with one preinfusion baseline and two recovery periods in between. MEASUREMENTS AND MAIN RESULTS: A significant (p less than .01) increase in resting energy expenditure was observed in response to the two highest dopamine infusion rates (5 and 10 micrograms/kg.min), corresponding to 6% and 15% median increases, respectively, as compared with preinfusion values. At the lowest dopamine infusion rate, no variation in resting energy expenditure was observed. Dopamine induced a significant (p less than .01) increase in hyperglycemia at all three infusion rates, and, at the highest infusion rate, dopamine induced a significant (p less than .05) increase of plasma free fatty acid concentrations. Insulin plasma concentrations were significantly (p less than .05 to p less than 0.1) increased at the three dopamine infusion rates. CONCLUSIONS: Dopamine infusion produces a dose-dependent thermogenic effect and induces various metabolic actions in man.

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Abstract: Protective immune responses against pathogen invasion and transformed cells requires the coordinated action of distinct leukocyte subsets and soluble factors, overall termed immunological network. Among antigen-presenting cells (APC), a crucial role is played by dendritic cells (DC), which initiate, amplify and determine the outcome of the immune response. Micro-environmental conditions profoundly influence DC in such ways that the resulting immune response ranges from successful immune stimulation to abortive response or immune suppression. For instance, the presence in the milieu of anti-inflammatory cytokine interleukin-10 (IL-10) reverts most of the effects mediated on DC by even strong pro-inflammatory agents such as bacterial Lipopolysaccharide (LPS), in terms of differentiation, activation and functions. In an environment containing both LPS and IL-10, uncoupling of receptors for inflammatory chemokines already occurs after a few hours and in a reversible manner on DC, allowing scavenging of chemokines and, consequently, attenuation of the inflammatory process which could be deleterious to the organism. By studying the effects on DC of concomitant stimulation by LPS and IL-10 from the gene expression point of view, we were able to define four distinct transcriptional programs: A. the inhibition of inflammation and immunity, B. the regulation of tissue remodeling, C. the tuning of cytokine/growth factor receptors and G protein-coupled receptors, D. the stimulation of B cell function and lymphoid tissue neogenesis. Among the latter genes, we further demonstrated that IL-10 synergizes with Toll-like receptor ligands for the production of functionally active B cell attracting chemokine CXCL13. Our data provide evidence that the combined exposure of APC to LPS and IL-10, via the production of CXCL13, involves humoral immunity by attracting antibody-producing cells. It is well known that the persistent release of CXCL13 leads to the development of ectopic lymphoid tissue aggregates and production of high levels of antibodies, thus favoring the induction of auto-immunity. Our findings suggest that the IL-10 produced in chronic inflammatory conditions may promote lymphoid tissue neogenesis through increased release of CXCL13. IL-10 is an anti-inflammatory cytokine inhibiting cellular-mediated TH 1-polarized immune responses. In this study we demonstrate that IL- 10 strongly supports the development of humoral immunity. IL-10 and CXCL13 can thus be targets for specific therapies in auto-immune diseases.

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El estudio de las variables relacionadas con la adquisición de las lenguas escolares en contextos bilingües y multilingües ha resurgido a raíz de la incorporación de alumnado extranjero al sistema educativo español. En este sentido, y gracias a su peculiar situación sociolingüística, Cataluña se ha convertido en un observatorio perfecto para estudiar el proceso de adquisición de lenguas del alumnado extranjero. En este artículo presentamos una parte de los datos obtenidos en la evaluación del conocimiento de catalán y del castellano de 668 alumnos extranjeros de sexto de Primaria escolarizados en 57 centros de Cataluña. Con ello pretendemos estudiar los efectos de la presencia y del uso social de las lenguas escolares en el conocimiento lingüístico de este alumnado. La hipótesis principal es que el desarrollo de buenos niveles de conocimiento escrito de las lenguas escolares por parte de los alumnos extranjeros depende, en buena medida, de las oportunidades que haya en el entorno social para que ellos puedan utilizar estas lenguas en los intercambios comunicativos informales con sus compañeros o con otros adultos. Las conclusiones del trabajo señalan las relaciones existentes entre el desarrollo de habilidades lingüísticas conversacionales y el de habilidades lingüísticas cognitivo-académicas (Cummins, 1979b), en el sentido de que tanto el conocimiento escrito de catalán como el de castellano que tiene el alumnado extranjero están condicionados por el nivel de desarrollo conversacional previo en ambas lenguas. Además, apuntan a que la transferencia de habilidades lingüísticas cognitivo-académicas no se produce directamente entre el catalán y el castellano, sino que depende fundamentalmente de la presencia social que tengan estas lenguas y de sus usos informales. Así, en la medida en que un buen número de estudiantes extranjeros no desarrolla suficiente competencia lingüística conversacional ni en catalán ni en castellano, el proceso de adquisición de las lenguas escolares se alarga más allá de los seis años

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Variation in body iron is associated with or causes diseases, including anaemia and iron overload. Here, we analyse genetic association data on biochemical markers of iron status from 11 European-population studies, with replication in eight additional cohorts (total up to 48,972 subjects). We find 11 genome-wide-significant (P<5 × 10(-8)) loci, some including known iron-related genes (HFE, SLC40A1, TF, TFR2, TFRC, TMPRSS6) and others novel (ABO, ARNTL, FADS2, NAT2, TEX14). SNPs at ARNTL, TF, and TFR2 affect iron markers in HFE C282Y homozygotes at risk for hemochromatosis. There is substantial overlap between our iron loci and loci affecting erythrocyte and lipid phenotypes. These results will facilitate investigation of the roles of iron in disease.