995 resultados para Organic group
Resumo:
Puerperium is a period of great changes in women's lives, in physiological, psychological and socio-cultural terms. Female sexuality is a broad topic that should be explored vis-à-vis the singularity of woman's experiences which themselves vary at different moments in time. This article is part of the project: Sexuality in the Puerperium, the objective of which was to understand what women's experience of their sexuality is in the postpartum period. Observation and semi-structured interview were used. The research approach was qualitative and narrative was used as the conceptual and methodological method. Six primiparas who gave birth in a public hospital in São Paulo took part in the study. Observation took place in the in-patients unit in the immediate post-partum period. The interviews were conducted in the women´s homes. The results of the study have enabled an understanding to be formed of the meanings and changes in sexuality during the postpartum period as well as of the experiences every woman faces in her new roles, relationships and difficulties.
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Background: The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibility to different pathogens. It has been estimated that all genetic variation underlying the human ABO alleles appeared along the human lineage, after the divergence from the chimpanzee lineage. A paleogenetic analysis of the ABO blood group gene in Neandertals allows us to directly test for the presence of the ABO alleles in these extinct humans. Results: We have analysed two male Neandertals that were retrieved under controlled conditions at the El Sidron site in Asturias (Spain) and that appeared to be almost free of modern human DNA contamination. We find a human specific diagnostic deletion for blood group O (O01 haplotype) in both Neandertal individuals. Conclusion: These results suggest that the genetic change responsible for the O blood group in humans predates the human and Neandertal divergence. A potential selective event associated with the emergence of the O allele may have therefore occurred after humans separated from their common ancestor with chimpanzees and before the human-Neandertal population divergence.
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Because of their beneficial impact on forest ecosystems, European red wood ants (Formica rufa group) are protected by law in many European countries and are considered to be among the most reliable bioindicators of forest stability. However, their taxonomy has been much debated and, unfortunately, it is too often neglected. This happens mainly because the morphology-based method for species delimitation requires lots of time and experience. We therefore employed 9 microsatellite loci and mitochondrial DNA (COI gene) to verify the power of genetic markers for red wood ant species delimitation and to investigate the cryptic diversity of these ants within the Eastern Swiss Alps. We analyzed 83 nests belonging to all red wood ant species that occur in the Swiss National Park area. Genetic data indicated that these species represent different genetic pools. Moreover, results showed that Formica aquilonia YARROW, 1955 and F. paralugubris SEIFERT, 1996 often hybridize within the Park, confirming that these two species are genetically very close and could have diverged only recently. Nevertheless, microsatellites also revealed that one entire population, located in the Minger Valley and morphologically identified as F. lugubris ZETTERSTEDT, 1838, is genetically different to all other analyzed F. lugubris populations found within the same area and to other red wood ant species. These findings, confirmed by mitochondrial DNA analyses, suggest the existence of a new cryptic species within the Eastern Swiss Alps. This putative cryptic species has been provisionally named F. lugubris-A2. These results have a great importance for future conservation plans, monitoring and evolutionary studies on these protected ants.
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Little attention has been paid so far to the influence of the chemical nature of the substance when measuring δ 15N by elemental analysis (EA)-isotope ratio mass spectrometry (IRMS). Although the bulk nitrogen isotope analysis of organic material is not to be questioned, literature from different disciplines using IRMS provides hints that the quantitative conversion of nitrate into nitrogen presents difficulties. We observed abnormal series of δ 15N values of laboratory standards and nitrates. These unexpected results were shown to be related to the tailing of the nitrogen peak of nitrate-containing compounds. A series of experiments were set up to investigate the cause of this phenomenon, using ammonium nitrate (NH4NO3) and potassium nitrate (KNO3) samples, two organic laboratory standards as well as the international secondary reference materials IAEA-N1, IAEA-N2-two ammonium sulphates [(NH4)2SO4]-and IAEA-NO-3, a potassium nitrate. In experiment 1, we used graphite and vanadium pentoxide (V2O5) as additives to observe if they could enhance the decomposition (combustion) of nitrates. In experiment 2, we tested another elemental analyser configuration including an additional section of reduced copper in order to see whether or not the tailing could originate from an incomplete reduction process. Finally, we modified several parameters of the method and observed their influence on the peak shape, δ 15N value and nitrogen content in weight percent of nitrogen of the target substances. We found the best results using mere thermal decomposition in helium, under exclusion of any oxygen. We show that the analytical procedure used for organic samples should not be used for nitrates because of their different chemical nature. We present the best performance given one set of sample introduction parameters for the analysis of nitrates, as well as for the ammonium sulphate IAEA-N1 and IAEA-N2 reference materials. We discuss these results considering the thermochemistry of the substances and the analytical technique itself. The results emphasise the difference in chemical nature of inorganic and organic samples, which necessarily involves distinct thermochemistry when analysed by EA-IRMS. Therefore, they should not be processed using the same analytical procedure. This clearly impacts on the way international secondary reference materials should be used for the calibration of organic laboratory standards.
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Tillage systems play a significant role in agricultural production throughout Iowa and the Midwest. It has been well documented that increased tillage intensities can reduce soil organic matter in the topsoil due to increased microbial activity and carbon (C ) oxidation. The potential loss of soil organic matter due to tillage operations is much higher for high organic matter soils than low organic matter soils. Tillage effects on soil organic matter can be magnified through soil erosion and loss of soil productivity. Soil organic matter is a natural reservoir for nutrients, buffers against soil erosion, and improves the soil environment to sustain soil productivity. Maintaining soil productivity requires an agriculture management system that maintains or improves soil organic matter content. Combining cropping systems and conservation tillage practices, such as no-tillage, strip-tillage, or ridge-tillage, are proven to be very effective in improving soil organic matter and soil quality.
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Robertsonian (Rb) fusions received large theoretical support for their role in speciation, but empirical evidence is often lacking. Here, we address the role of Rb rearrangements on the genetic differentiation of the karyotypically diversified group of shrews, Sorex araneus. We compared genetic structure between 'rearranged' and 'common' chromosomes in pairwise comparisons of five karyotypic taxa of the group. Considering all possible comparisons, we found a significantly greater differentiation at rearranged chromosomes, supporting the role of chromosomal rearrangements in the general genetic diversification of this group. Intertaxa structure and distance were larger across rearranged chromosomes for most of the comparisons, although these differences were not significant. This last result could be explained by the large variance observed among microsatellite-based estimates. The differences observed among the pairs of taxa analysed support the role of both the hybrid karyotypic complexity and the level of evolutionary divergence.
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When applying a Collaborative Learning Flow Pattern (CLFP) to structure sequences of activities in real contexts, one of the tasks is to organize groups of students according to the constraints imposed by the pattern. Sometimes,unexpected events occurring at runtime force this pre-defined distribution to be changed. In such situations, an adjustment of the group structures to be adapted to the new context is needed. If the collaborative pattern is complex, this group redefinitionmight be difficult and time consuming to be carried out in real time. In this context, technology can help on notifying the teacher which incompatibilitiesbetween the actual context and the constraints imposed by the pattern. This chapter presents a flexible solution for supporting teachers in the group organization profiting from the intrinsic constraints defined by a CLFPs codified in IMS Learning Design. A prototype of a web-based tool for the TAPPS and Jigsaw CLFPs and the preliminary results of a controlled user study are alsopresented as a first step towards flexible technological systems to support grouping tasks in this context.
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Evaluating the possible benefits of the introduction of genetically modified (GM) crops must address the issue of consumer resistance as well as the complex regulation that has ensued. In the European Union (EU) this regulation envisions the “co-existence” of GM food with conventional and quality-enhanced products, mandates the labelling and traceability of GM products, and allows only a stringent adventitious presence of GM content in other products. All these elements are brought together within a partial equilibrium model of the EU agricultural food sector. The model comprises conventional, GM and organic food. Demand is modelled in a novel fashion, whereby organic and conventional products are treated as horizontally differentiated but GM products are vertically differentiated (weakly inferior) relative to conventional ones. Supply accounts explicitly for the land constraint at the sector level and for the need for additional resources to produce organic food. Model calibration and simulation allow insights into the qualitative and quantitative effects of the large-scale introduction of GM products in the EU market. We find that the introduction of GM food reduces overall EU welfare, mostly because of the associated need for costly segregation of non-GM products, but the producers of quality-enhanced products actually benefit.
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Background: Mutism and dense retrograde amnesia are found both in organic and dissociative contexts. Moreover, dissociative symptoms may be modulated by right prefrontal activity. A single case, M.R., developed left hemiparesis, mutism and retrograde amnesia after a high-voltage electric shock without evidence of lasting brain lesions. M.R. suddenly recovered from his mutism following a mild brain trauma 2 years later. Methods: M.R.'s neuropsychological pattern and anatomoclinical correlations were studied through (i) language and memory assessment to characterize his deficits, (ii) functional neuroimaging during a standard language paradigm, and (iii) assessment of frontal and left insular connectivity through diffusion tractography imaging and transcranial magnetic stimulation. A control evaluation was repeated after recovery. Findings: M.R. recovered from the left hemiparesis within 90 days of the accident, which indicated a transient right brain impairment. One year later, neurobehavioral, language and memory evaluations strongly suggested a dissociative component in the mutism and retrograde amnesia. Investigations (including MRI, fMRI, diffusion tensor imaging, EEG and r-TMS) were normal. Twenty-seven months after the electrical injury, M.R. had a very mild head injury which was followed by a rapid recovery of speech. However, the retrograde amnesia persisted. Discussion: This case indicates an interaction of both organic and dissociative mechanisms in order to explain the patient's symptoms. The study also illustrates dissociation in the time course of the two different dissociative symptoms in the same patient.
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This study analyses the characteristics of members leaving a Spanishunion federation – Catalonia branch of Workers’ Commissions(CCOO-Catalonia), together with their reasons for leaving using avariety of data sources. Our findings indicate that higher union attritionamong members in instable employment (i.e. casual employment andlow seniority). In general, union leavers confirm that their job situationis an important reason for leaving the union. We therefore concludethat efforts made by the union to retain members in vulnerable labormarket positions are important in reducing high rates of union attritionin Spain.
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The role of albumin in tubular secretion of the organic anions p-aminohippurate (PAH, 21% albumin-bound at 1 microM) and methotrexate (MTX, 55% bound at 1 microM), and of the organic cation N1-methylnicotinamide (NMN, not bound), was investigated in isolated rabbit S2 proximal tubules. PAH or MTX secretory rates were low in the absence of colloids or in the presence of 1 g/dl dextran 40, and were reversibly two- to sevenfold stimulated by either 1 g/dl bovine (BSA, either regular, defatted, and/or dialyzed) or rabbit serum albumin, or by dialyzed native rabbit plasma. NMN secretion was not stimulated by either dextran or albumin. Luminal BSA had no effect, but stimulation of PAH secretion was observed when albumin was present in both lumen and bath. This secretion was BSA concentration-dependent up to a 1 g/dl BSA. Saturation experiments suggested that 1 g/dl BSA may increase PAH apparent affinity for secretion, with no change in its maximum velocity. Albumin appears therefore to facilitate organic anion proximal secretion by an effect unrelated to oncotic pressure or to the extent of organic anion binding.
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In hybrid zones, endogenous counter-selection of hybrids is usually first expressed as reduced fertility or viability in hybrids of the heterogametic sex, a mechanism known as Haldane's rule. This phenomenon often leads to a differential of gene flow between sex-linked markers. Here, we address the possibility of a differential gene flow for Y chromosome, mtDNA and autosomal markers across the hybrid zone between the genetically and chromosomally well-differentiated species Sorex antinorii and Sorex araneus race Vaud. Intermarker comparison clearly revealed coincidental centre and very abrupt clines for all three types of markers. The overall level of genetic differentiation between the two species must be strong enough to hinder asymmetric introgression. Cyto-nuclear mismatches were also observed in the centre of hybrid zone. The significantly lower number of mismatches observed in males than in females possibly results from Y chromosome-mtDNA interactions. Results are compared with those previously reported in another hybrid zone between S. antinori and S. araneus race Cordon.