927 resultados para Permission to Date


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Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.

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An increasing focus in evolutionary biology is on the interplay between mesoscale ecological and evolutionary processes such as population demographics, habitat tolerance, and especially geographic distribution, as potential drivers responsible for patterns of diversification and extinction over geologic time. However, few studies to date connect organismal processes such as survival and reproduction through mesoscale patterns to long-term macroevolutionary trends. In my dissertation, I investigate how mechanism of seed dispersal, mediated through geographic range size, influences diversification rates in the Rosales (Plantae: Anthophyta). In my first chapter, I validate the phylogenetic comparative methods that I use in my second and third chapters. Available state speciation and extinction (SSE) models assumptions about evolution known to be false through fossil data. I show, however, that as long as net diversification rates remain positive – a condition likely true for the Rosales – these violations of SSE’s assumptions do not cause significantly biased results. With SSE methods validated, my second chapter reconstructs three associations that appear to increase diversification rate for Rosalean genera: (1) herbaceous habit; (2) a three-way interaction combining animal dispersal, high within-genus species richness, and geographic range on multiple continents; (3) a four-way interaction combining woody habit with the other three characteristics of (2). I suggest that the three- and four-way interactions represent colonization ability and resulting extinction resistance in the face of late Cenozoic climate change; however, there are other possibilities as well that I hope to investigate in future research. My third chapter reconstructs the phylogeographic history of the Rosales using both non-fossil-assisted SSE methods as well as fossil-informed traditional phylogeographic analysis. Ancestral state reconstructions indicate that the Rosaceae diversified in North America while the other Rosalean families diversified elsewhere, possibly in Eurasia. SSE is able to successfully identify groups of genera that were likely to have been ancestrally widespread, but has poorer taxonomic resolution than methods that use fossil data. In conclusion, these chapters together suggest several potential causal links between organismal, mesoscale, and geologic scale processes, but further work will be needed to test the hypotheses that I raise here.

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Temporally-growing frontal meandering and occasional eddy-shedding is observed in the Brazil Current (BC) as it flows adjacent to the Brazilian Coast. No study of the dynamics of this phenomenon has been conducted to date in the region between 22 degrees S and 25 degrees S. Within this latitude range, the flow over the intermediate continental slope is marked by a current inversion at a depth that is associated with the Intermediate Western Boundary Current (IWBC). A time series analysis of 10-current-meter mooring data was used to describe a mean vertical profile for the BC-IWBC jet and a typical meander vertical structure. The latter was obtained by an empirical orthogonal function (EOF) analysis that showed a single mode explaining 82% of the total variance. This mode structure decayed sharply with depth, revealing that the meandering is much more vigorous within the BC domain than it is in the IWBC region. As the spectral analysis of the mode amplitude time series revealed no significant periods, we searched for dominant wavelengths. This search was done via a spatial EOF analysis on 51 thermal front patterns derived from digitized AVHRR images. Four modes were statistically significant at the 95% confidence level. Modes 3 and 4, which together explained 18% of the total variance, are associated with 266 and 338-km vorticity waves, respectively. With this new information derived from the data, the [Johns, W.E., 1988. One-dimensional baroclinically unstable waves on the Gulf Stream potential vorticity gradient near Cape Hatteras. Dyn. Atmos. Oceans 11, 323-350] one-dimensional quasi-geostrophic model was applied to the interpolated mean BC-IWBC jet. The results indicated that the BC system is indeed baroclinically unstable and that the wavelengths depicted in the thermal front analysis are associated with the most unstable waves produced by the model. Growth rates were about 0.06 (0.05) days(-1) for the 266-km (338-km) wave. Moreover, phase speeds for these waves were low compared to the surface BC velocity and may account for remarks in the literature about growing standing or stationary meanders off southeast Brazil. The theoretical vertical structure modes associated with these waves resembled very closely to the one obtained for the current-meter mooring EOF analysis. We interpret this agreement as a confirmation that baroclinic instability is an important mechanism in meander growth in the BC system. (C) 2008 Elsevier B.V. All rights reserved.

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Background and aims: A gluten-free diet is to date the only treatment available to celiac disease sufferers. However, systematic reviews indicate that, depending on the method of evaluation used, only 42% to 91% of patients adhere to the diet strictly. Transculturally adapted tools that evaluate adherence beyond simple self-informed questions or invasive analyses are, therefore, of importance. The aim is to obtain a Spanish transcultural adaption and validation of Leffler's Celiac Dietary Adherence Test. Methods: A two-stage observational transversal study: translation and back translation by four qualified translators followed by a validation stage in which the questionnaire was administered to 306 celiac disease patients aged between 12 and 72 years and resident in Aragon. Factorial structure, criteria validity and internal consistency were evaluated. Results: The Spanish version maintained the 7 items in a 3-factor structure. Feasibility was very high in all the questions answered and the floor and ceiling effects were very low (4.3% and 1%, respectively). The Spearman correlation with the self-efficacy and life quality scales and the self-informed question were statistically significant (p < 0.01). According to the questionnaire criteria, adherence was 72.3%. Conclusion: The Spanish version of the Celiac Dietary Adherence Test shows appropriate psychometric properties and is, therefore, suitable for studying adherence to a gluten-free diet in clinical and research environments.

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Safe drug prescribing and administration are essential elements within undergraduate healthcare curricula, but medication errors, especially in paediatric practice, continue to compromise patient safety. In this area of clinical care, collective responsibility, team working and communication between health professionals have been identified as key elements in safe clinical practice. To date, there is limited research evidence as to how best to deliver teaching and learning of these competencies to practitioners of the future.An interprofessional workshop to facilitate learning of knowledge, core competencies, communication and team working skills in paediatric drug prescribing and administration at undergraduate level was developed and evaluated. The practical, ward-based workshop was delivered to 4th year medical and 3rd year nursing students and evaluated using a pre and post workshop questionnaire with open-ended response questions.Following the workshop, students reported an increase in their knowledge and awareness of paediatric medication safety and the causes of medication errors (p < 0.001), with the greatest increase noted among medical students. Highly significant changes in students' attitudes to shared learning were observed, indicating that safe medication practice is learnt more effectively with students from other healthcare disciplines. Qualitative data revealed that students' participation in the workshop improved communication and teamworking skills, and led to greater awareness of the role of other healthcare professionals.This study has helped bridge the knowledge-skills gap, demonstrating how an interprofessional approach to drug prescribing and administration has the potential to improve quality and safety within healthcare.

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Servitization and digitization together provide significant opportunities to raise the performance and profitability of the road transport industry. To date these opportunities are only sparsely captured and the potential economic, social and environmental value is forgone. We set out to investigate the barriers to capturing the value of servitization and digitization in the road transport industry.

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To date, there has been little consideration of the many different ways in which accounting and risk intersect, despite organisations being more determined than ever to build resilience against potential risks. This comprehensive volume overcomes this gap by providing an overview of the field, drawing together current knowledge of risk in a wide range of different accounting contexts.

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BACKGROUND Elephants are classified as critically endangered animals by the International Union for Conservation of Species (IUCN). Elephant endotheliotropic herpesvirus (EEHV) poses a large threat to breeding programs of captive Asian elephants by causing fatal haemorrhagic disease. EEHV infection is detected by PCR in samples from both clinically ill and asymptomatic elephants with an active infection, whereas latent carriers can be distinguished exclusively via serological assays. To date, identification of latent carriers has been challenging, since there are no serological assays capable of detecting seropositive elephants. RESULTS Here we describe a novel ELISA that specifically detects EEHV antibodies circulating in Asian elephant plasma/serum. Approximately 80 % of PCR positive elephants display EEHV-specific antibodies. Monitoring three Asian elephant herds from European zoos revealed that the serostatus of elephants within a herd varied from non-detectable to high titers. The antibody titers showed typical herpes-like rise-and-fall patterns in time which occur in all seropositive animals in the herd more or less simultaneously. CONCLUSIONS This study shows that the developed ELISA is suitable to detect antibodies specific to EEHV. It allows study of EEHV seroprevalence in Asian elephants. Results confirm that EEHV prevalence among Asian elephants (whether captive-born or wild-caught) is high.

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Arctic regions are expected to experience an increase in both temperature and precipitation over the coming decades, which is likely to impact vegetation dynamics and greenhouse gas exchange. To test this response, an experiment was installed at the Cape Bounty Arctic Watershed Observatory, on Melville Island, NU, in 2008 as part of the International Tundra Experiment (ITEX). Snow fences and open top chambers (OTCs) were used to manipulate snow depth and air temperature, respectively. Unlike most ITEX sites to date, enhanced temperature and snowfall were combined here in a factorial design with eight replicates. As an added control, four plots were established well outside the enhanced snow area. Senescence date was recorded at the end of the season, and at the peak of the growing season a vegetation survey was conducted within each plot in order to determine the total percent cover of each plot, as well as the percent cover of individual species. Carbon dioxide (CO2) exchange was also measured within each plot throughout the growing season. The date of senescence occurred significantly earlier in plots which had not been manipulated in any way, compared to all other treatments for all species. Salix arctica showed the greatest increase in cover over time at the species level. Lichen cover increased significantly in the deepened snow plots, and in general there were significant increases in percent cover in some functional groups over time. During June and into July the net CO2 flux was to the atmosphere. It was not until July 27 that these ecosystems became net carbon sinks. However, warming alone resulted in the ecosystem acting as a significant net carbon sink for the entire growing season. Plots exposed to warming alone were estimated to have removed approximately 19.94 g C m-2 from the atmosphere, whereas all other treatments were very similar to one another and estimated to have added approximately 3.12 g C m-2 to the atmosphere. Active layer depth and soil temperatures suggest that plots within the ambient snow zone may be receiving some additional snow due to their proximity to the fences. CO2 fluxes measured within the outer control plots suggest that the effect of warming alone could lead to this ecosystem being an even stronger net C sink under truly ambient snow conditions.