944 resultados para Expected and observed heterozygosity


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BACKGROUND Even among HIV-infected patients who fully suppress plasma HIV RNA replication on antiretroviral therapy, genetic (e.g. CCL3L1 copy number), viral (e.g. tropism) and environmental (e.g. chronic exposure to microbial antigens) factors influence CD4 recovery. These factors differ markedly around the world and therefore the expected CD4 recovery during HIV RNA suppression may differ globally. METHODS We evaluated HIV-infected adults from North America, West Africa, East Africa, Southern Africa and Asia starting non-nucleoside reverse transcriptase inhibitorbased regimens containing efavirenz or nevirapine, who achieved at least one HIV RNA level <500/ml in the first year of therapy and observed CD4 changes during HIV RNA suppression. We used a piecewise linear regression to estimate the influence of region of residence on CD4 recovery, adjusting for socio-demographic and clinical characteristics. We observed 28 217 patients from 105 cohorts over 37 825 person-years. RESULTS After adjustment, patients from East Africa showed diminished CD4 recovery as compared with other regions. Three years after antiretroviral therapy initiation, the mean CD4 count for a prototypical patient with a pre-therapy CD4 count of 150/ml was 529/ml [95% confidence interval (CI): 517–541] in North America, 494/ml (95% CI: 429–559) in West Africa, 515/ml (95% CI: 508–522) in Southern Africa, 503/ml (95% CI: 478–528) in Asia and 437/ml (95% CI: 425–449) in East Africa. CONCLUSIONS CD4 recovery during HIV RNA suppression is diminished in East Africa as compared with other regions of the world, and observed differences are large enough to potentially influence clinical outcomes. Epidemiological analyses on a global scale can identify macroscopic effects unobservable at the clinical, national or individual regional level.

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INTRODUCTION The knowledge about adaptive mechanisms of monochorionic placentas to fulfill the demands of two instead of one fetus is largely speculative. The aim of our study was to investigate the impact of chorionicity on birth weight and placental weight in twin pregnancies. METHODS Forty Monochorionic (MC) and 43 dichorionic (DC) twin pregnancies were included in this retrospective study. Individual and total (sum of both twins) birth weights, placental weights ratios between placental and birth weights and observed-to-expected (O/E)-ratios were calculated and analyzed. Additionally, we investigated whether in twin pregnancies placental and birth weights follow the law of allometric metabolic scaling. RESULTS MC pregnancies showed higher placental O/E-ratios than DC ones (2.25 ± 0.85 versus 1.66 ± 0.61; p < 0.05), whereas the total neonatal birth weight O/E-ratios were not different. In DC twins total placental weights correlated significantly with gestational age (r = 0.74, p < 0.001), but not in MC twins. Analysis of deliveries ≤32 weeks revealed that the placenta to birth weight ratio in MC twins was higher than in matched DC twins (0.49 ± 0.3 versus 0.24 ± 0.03; p = 0.03). Allometric metabolic scaling revealed that dichorionic twin placentas scale with birth weight, while the monochorionic ones do not. DISCUSSION The weight of MC placentas compared to that of DC is not gestational age dependent in the third trimester. Therefore an early accelerated placental growth pattern has to be postulated which leads to an excess placental mass particularly below 32 weeks of gestation. The monochorionic twins do not follow allometric metabolic scaling principle making them more vulnerable to placental compromise.

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For over 3 centuries, diameter-limit harvesting has been a predominant logging method in the northeastern United States. Silvicultural theory asserts that such intensively selective harvesting can lead to genetic degradation. A decrease in softwood productivity has recently been reported in Maine - has a long history of dysgenic selection degraded the genetic resources of Maine softwoods, contributing to a decrease in growth and productivity? This study examines two aspects of potential implications of diameter-limit harvesting: effects on residual phenotypes of red spruce and impacts on genetic diversity of white pine. Radial growth of residual red spruce trees in stands experiencing 50 years of fixed diameter-limit harvesting was measured using annual increment rings and compared with residual red spruce trees in positive selection stands. Trees remaiaing after several rounds of diameter-limit harvesting exhibited sigdicantl y smaller radial sizes throughout their lives, and displayed significantly slower growth rates for the first 80 years of measured growth. These results strongly suggest that the largest and fastest-growing genotypes and their respective gene complexes determining good radial growth have been removed from the diameter-limit stand. Dysgenic selection can be observed in fixed diarneter-limit stands, resulting in a diminished genetic resource and decreased residual stand value. To examine more direct genetic implications of long-term diameter-limit harvesting, microsatellite DNA markers were implemented to study genetic diversity of eastern white pine in Maine. Three age groups of trees were studied: mature trees older than 200 years, juvenile trees 5-30 years old, and embryos. Trees were genotyped at 10 microsatellite loci. Overall genetic diversity levels of eastern white pine in Maine were extremely high, with an average observed heterozygosity of 0.762. Genetic differentiation was minimal among and between all three age groups, although an excess of heterozygotes was shown in the mature and juvenile groups that was not reflected in the embryo group, which actually had a slight heterozygote deficiency. Allele frequencies did not differ significantly between age groups, but did reveal more rare and low frequency alleles in the embryo groups than in the mature group. Overall, low frequency alleles comprise the largest portion of alleles in the sample population, with no common alleles evident overall. These results suggest that significant genetic degradation has either not occurred for white pine, or that the results of dysgenic selection have not yet emerged. It is clear, however, that selective harvesting could result in a loss of low frequency alleles, which are a primary reserve of evolutionary potential in a species. Implications of these studies affect industrial forestry, regional economics, and ecological concerns for the northeast. Long-term diameter-limit harvesting can lead to a degradation of residual phenotypes, and an overall decrease in stand quality. Potentially, a loss of low frequency, locally adapted alleles could result in a decrease of allelic richness and degradation of the regidnal genetic resource. Decreased genetic variation can lead to seriously limited evolutionary potential of species and ecosystems, particularly in rapidly changing environments. Based on these findings, I recommend a reassessment of any harvesting prescription that includes fixed diameter-limit removals, particularly for species that have low natural genetic diversity levels or a limited natural range, such as red spruce. Maintenance of a healthy genetic reserve can avoid effects of dysgenic harvesting.

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Siete variedades de vid empleadas en Argentina para la elaboración de vinos de alta gama fueron caracterizadas molecularmente a través del empleo de microsatélites. Seis de los 8 pares de cebadores usados amplificaron patrones de bandas reproducibles. El número de alelos detectados por locus varió entre 5 y 10, con un total de 42 alelos, registrándose desde 1 a 7 alelos únicos. El número de genotipos microsatélites encontrados para cada locus osciló entre 3 y 7, con un total de 28. Las variedades Tempranillo y Chenin mostraron 6 y 5 genotipos «únicos», respectivamente, con los 6 loci analizados. La heterocigosidad observada varió entre 42,9 y 100 %, mientras que la heterocigosidad esperada osciló entre 64,3 y 87,8 %. El locus más informativo fue VrZAG79 (con un contenido de información polimórfica de 84,9 % y un número de alelos efectivos de 8,17) mientras que el menos informativo fue VrZAG62. La probabilidad acumulada de obtener genotipos idénticos fue de 7,68 x 10-05 indicando que, mediante el uso combinado de estos 6 cebadores microsatélites se pueden discriminar todas las variedades ensayadas, con alto grado de certeza. El análisis de agrupamiento por el método UPGMA separó claramente las variedades francesas (Merlot, Pinot Noir y Cabernet Sauvignon) y Syrah de los cepajes Tempranillo y Bonarda. Esta técnica podría ofrecerse como servicio a viveristas y productores vitícolas interesados en garantizar la identidad genética de sus materiales comercializados.

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Envisat Advanced Synthetic Aperture Radar (ASAR) Wide Swath Mode (WSM) images are used to derive C-band HH-polarization normalized radar cross sections (NRCS). These are compared with ice-core analysis and visual ship-based observations of snow and ice properties observed according to the Antarctic Sea Ice Processes and Climate (ASPeCt) protocol during two International Polar Year summer cruises (Oden 2008 and Palmer 2009) in West Antarctica. Thick first-year (TFY) and multi-year (MY) ice were the dominant ice types. The NRCS value ranges between -16.3 ± 1.1 and -7.6 ± 1.0 dB for TFY ice, and is -12.6 ± 1.3 dB for MY ice; for TFY ice, NRCS values increase from ~-15 dB to -9 dB from December/January to mid-February. In situ and ASPeCt observations are not, however, detailed enough to interpret the observed NRCS change over time. Co-located Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) vertically polarized 37 GHz brightness temperatures (TB37V), 7 day and 1 day averages as well as the TB37V difference between ascending and descending AMSR-E overpasses suggest the low NRCS values (-15 dB) are associated with snowmelt being still in progress, while the change towards higher NRCS values (-9dB) is caused by commencement of melt-refreeze cycles after about mid-January.

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An understanding of the adaptability of belugas (Delphinapterus leucas) to changing ice conditions is required to interpret and predict possible changes in habitat selection in response to projected loss of sea ice throughout the circumpolar Arctic. We analyzed beluga observations made during spring aerial surveys for ringed seals conducted from 1975 to 1979 in the eastern Beaufort Sea. Despite interannual variability in the extent and distribution of sea ice, belugas consistently selected areas with water depths of 200-500 m and heavy ice concentrations (8/10 to 10/10) while areas of open water to light ice concentrations (0/10 to 1/10) were not selected. Belugas were also found in proximity to regions with >0.5 degrees seafloor slope which include the continental slope and other areas with the potential for oceanographic upwellings. In most years (4 of 5), fast-ice edges and coastal areas were not selected. In the lightest ice year analyzed, belugas showed less specificity in habitat selection as their distribution expanded and shifted shoreward to fast-ice edges. The observed distribution is discussed in terms of predator-prey relationships particularly with reference to beluga feeding on polar cod (Boreogadus saida). More research is required to examine and compare possible changes in distribution since the late 1970s and to investigate the factors driving the patterns described.

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Recent research has shown large differences between the expected and the actual energy consumption in buildings. The differences have been attributed partially, to the assumptions made during the design phase of buildings when simulation methods are employed. More accurate occupancy profiles on building operation could help to carry out more precise building performance calculations. This study focuses on the post-occupancy evaluation of two apartments, one renovated and one non renovated, in Madrid within the same building complex. The aim of this paper is to present an application of the mixed-methods methodology (Creswell, 2007) to assess thermal comfort and occupancy practices used in the case studies, and to discuss the shortcomings and opportunities associated with it. The mixed-methods methodology offers strategies for integrating qualitative and quantitative methods to investigate complex phenomena. This approach is expected to contribute to the growing knowledge of occupants’ behaviour and building performance by explaining the differences observed between energy consumption and thermal comfort in relation to people’s saving and comfort practices and the related experiences, preferences and values.

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The knowledge of insulation debris generation and transport gains in importance regarding reactor safety research for PWR and BWR. The insulation debris released near the break consists of a mixture of very different fibres and particles concerning size, shape, consistence and other properties. Some fraction of the released insulation debris will be transported into the reactor sump where it may affect emergency core cooling. Experiments are performed to blast original samples of mineral wool insulation material by steam under original thermal-hydraulic break conditions of BWR. The gained fragments are used as initial specimen for further experiments at acrylic glass test facilities. The quasi ID-sinking behaviour of the insulation fragments are investigated in a water column by optical high speed video techniques and methods of image processing. Drag properties are derived from the measured sinking velocities of the fibres and observed geometric parameters for an adequate CFD modelling. In the test rig "Ring line-II" the influence of the insulation material on the head loss is investigated for debris loaded strainers. Correlations from the filter bed theory are adapted with experimental results and are used to model the flow resistance depending on particle load, filter bed porosity and parameters of the coolant flow. This concept also enables the simulation of a particular blocked strainer with CFDcodes. During the ongoing work further results of separate effect and integral experiments and the application and validation of the CFD-models for integral test facilities and original containment sump conditions are expected.

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The present study aimed to develop microsatellite markers (SSR) for Copernicia prunifera; and characterize the demographic pattern and the spatial genetic structure (SGS) in different development stages of C. prunifera in a natural population of Rio Grande do Norte (RN) by using ISSR molecular markers. 17 SSR primers pairs were developed, which were tested by using DNA from samples of different populations. The demographic and genetic spatial structure was assessed in a plot with an area of 0.55 ha, where all individuals were georeferenced. The molecular analyses with the use of microsatellite markers pointed out that all built primers pairs, when submitted to PCR, had amplification. They showed sizes of base pairs ranging between 113 and 250 bp. The demographic analyses showed a clustered standard of spatial distribution in the first distance classes, random between 40 and 50 m and segregated in higher distances. Eight ISSR primers were used, thereby producing a total of 102 loci, with 100 of them being polymorphic. Among the three stages, the young showed the highest Nei’s genetic diversity index (He = 0.37); whilst the lowest index was found in the reproductive adults (He = 0.34). The AMOVA results showed a greater genetic differentiation within the development stages (98.61%) in comparison to the interval among the stages (1.39%). The total population (n = 161) showed a positive and significant relationship of kinship in the first distance class (12.3 m). The young showed a significant kinship up to 10.5 m and negative in the fifth distance class (37.6 m). The non-reproductive adults had a positive relationship of kinship in the first distance class (11.0 m) and random distribution of genotypes in the remaining classes. The reproductive adults showed genotypes spatially distributed in a random way. The values for the genetic bottleneck tests proved that the number of loci with excess observed heterozygosity was greater than expected. The SGS results reflect the restricted dispersion of the species, and the bottleneck tests reflect the reduction genotypes provoked by the anthropization of natural environments of C. prunifera.

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Improvements in genomic technology, both in the increased speed and reduced cost of sequencing, have expanded the appreciation of the abundance of human genetic variation. However the sheer amount of variation, as well as the varying type and genomic content of variation, poses a challenge in understanding the clinical consequence of a single mutation. This work uses several methodologies to interpret the observed variation in the human genome, and presents novel strategies for the prediction of allele pathogenicity.

Using the zebrafish model system as an in vivo assay of allele function, we identified a novel driver of Bardet-Biedl Syndrome (BBS) in CEP76. A combination of targeted sequencing of 785 cilia-associated genes in a cohort of BBS patients and subsequent in vivo functional assays recapitulating the human phenotype gave strong evidence for the role of CEP76 mutations in the pathology of an affected family. This portion of the work demonstrated the necessity of functional testing in validating disease-associated mutations, and added to the catalogue of known BBS disease genes.

Further study into the role of copy-number variations (CNVs) in a cohort of BBS patients showed the significant contribution of CNVs to disease pathology. Using high-density array comparative genomic hybridization (aCGH) we were able to identify pathogenic CNVs as small as several hundred bp. Dissection of constituent gene and in vivo experiments investigating epistatic interactions between affected genes allowed for an appreciation of several paradigms by which CNVs can contribute to disease. This study revealed that the contribution of CNVs to disease in BBS patients is much higher than previously expected, and demonstrated the necessity of consideration of CNV contribution in future (and retrospective) investigations of human genetic disease.

Finally, we used a combination of comparative genomics and in vivo complementation assays to identify second-site compensatory modification of pathogenic alleles. These pathogenic alleles, which are found compensated in other species (termed compensated pathogenic deviations [CPDs]), represent a significant fraction (from 3 – 10%) of human disease-associated alleles. In silico pathogenicity prediction algorithms, a valuable method of allele prioritization, often misrepresent these alleles as benign, leading to omission of possibly informative variants in studies of human genetic disease. We created a mathematical model that was able to predict CPDs and putative compensatory sites, and functionally showed in vivo that second-site mutation can mitigate the pathogenicity of disease alleles. Additionally, we made publically available an in silico module for the prediction of CPDs and modifier sites.

These studies have advanced the ability to interpret the pathogenicity of multiple types of human variation, as well as made available tools for others to do so as well.

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Increased atmospheric CO2 concentrations are causing greater dissolution of CO2 into seawater, and are ultimately responsible for today's ongoing ocean acidification. We manipulated seawater acidity by addition of HCl and by increasing CO2 concentration and observed that two coastal harpacticoid copepods, Amphiascoides atopus and Schizopera knabeni were both more sensitive to increased acidity when generated by CO2. The present study indicates that copepods living in environments more prone to hypercapnia, such as mudflats where S. knabeni lives, may be less sensitive to future acidification. Ocean acidification is also expected to alter the toxicity of waterborne metals by influencing their speciation in seawater. CO2 enrichment did not affect the free-ion concentration of Cd but did increase the free-ion concentration of Cu. Antagonistic toxicities were observed between CO2 with Cd, Cu and Cu free-ion in A. atopus. This interaction could be due to a competition for H+ and metals for binding sites.

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Thesis (Master's)--University of Washington, 2016-06

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Humour production and showing mirth (i.e., smiling and laughing) confer prosocial advantages. However, there is a paucity of literature evaluating how humour manifests in psychopathology. Humour and mirth may be especially relevant in depression, wherein profound impairments are evident in emotional and social functioning. Chapters 2 and 3 present correlational and predictive relations of depressive, social anxiety, and social anhedonia symptoms with humour styles, and consider the role of motivational systems and expressivity of positive affect as they relate to humour. As expected, symptoms and avoidance-based motivation were positively related to maladaptive humour styles and negatively related to adaptive humour styles. Interestingly, the pattern of relations shifted when considered among individuals in a depressive episode; acutely depressed individuals generally shy away from any humour style rather than gravitating toward specific styles. In a mediation model, the inverse relation between depressive symptoms and affiliative humour was fully mediated by approach-based motivation and expressivity of positive emotions. Chapters 4 and 5 examined subjective and observed mirth responses (facial affect and laughter) demonstrated by depressed and healthy comparison groups. Relative to non-depressed individuals, depressed persons reported less enjoyment, lower ratings of funniness, and fewer instances and shorter durations of positive facial affect and laughter when viewing humourous videos. There was no significant change in retrospective ratings of enjoyment and funniness at a one-week follow-up. The pattern of responsivity by depressed persons shifted when they viewed humourous videos while hearing others laughing. Both groups demonstrated more mirth when hearing others laugh; there were no differences between groups on mirthful behaviours. The one exception was that the total duration of laugher produced by depressed individuals was shorter than that produced by individuals in the healthy comparison group. This research project demonstrates that facets of depressive symptomatology are differentially associated with humour use and depressed individuals show blunted emotional responsivity to humourous stimuli. However, the pattern of reduced affective responsivity is context specific in that it fluctuates in response to hearing others’ laughter. These findings have important implications for the conceptualization of depression and the subsequent avenues for the treatment of individuals with depression.

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Energy dispersive X-ray spectroscopy microanalysis (EDX), scanning electron microscopy (SEM), and Archimedes' Principle were used to determine the characteristics of inorganic filler particles in five dental alginates, including Cavex ColorChange (C), Hydrogum 5 (H5), Hydrogum (H), Orthoprint (O), and Jeltrate Plus (JP). The different alginate powders (0.5 mg) were fixed on plastic stubs (n = 5) and sputter coated with carbon for EDX analysis, then coated with gold, and observed using SEM. Volume fractions were determined by weighing a sample of each material in water before and after calcining at 450(°)C for 3 h. The alginate materials were mainly composed of silicon (Si) by weight (C-81.59%, H-79.89%, O-78.87%, H5-77.95%, JP-66.88%, wt). The filler fractions in volume (vt) were as follows: H5-84.85%, JP-74.76%, H-70.03%, O-68.31%, and C-56.10%. The tested materials demonstrated important differences in the inorganic elemental composition, filler fraction, and particle morphology.

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This article deals with the scavenging processes modeling of the particulate sulfate and the gas sulfur dioxide, emphasizing the synoptic conditions at different sampling sites in order to verify the domination of the in-cloud or below-cloud scavenging processes in the Metropolitan Area of São Paulo (RMSP). Three sampling sites were chosen: GV (Granja Viana) at RMSP surroundings, IAG-USP and Mackenzie (RMSP center). Basing on synoptic conditions, it was chosen a group of events where the numerical modeling, a simple scavenging model, was used. These synoptic conditions were usually convective cloud storms, which are usual at RMSP. The results show that the in-cloud processes were dominant (80%) for sulfate/sulfur dioxide scavenging processes, with below-cloud process indicating around 20% of the total. Clearly convective events, with total rainfall higher than 20 mm, are better modeled than the stratiform events, with correlation coefficient of 0.92. There is also a clear association with events presenting higher rainfall amount and the ratio between modeled and observed data set with correlation coefficient of 0.63. Additionally, the suburb sampling site, GV, as expected due to the pollution source distance, presents in general smaller amount of rainwater sulfate (modeled and observed) than the center sampling site, Mackenzie, where the characterization event explains partially the rainfall concentration differences.