839 resultados para life time
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Tese dout., Ecologia, Universidade do Algarve, 2006
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The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.
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Background Although it is now widely endorsed that children should as far as possible rate their own health related quality of life (HRQL), there are situations where proxy information on child HRQL may be useful, especially where a child is too ill or young to provide their own HRQL assessment. There is limited availability of generic HRQL scales that have a parallel child and parent version and that are reliable, valid, brief, comprehensible and suitable for use in UK populations. The aims of this study were therefore to develop and validate a parent version of the anglicised Manchester-Minneapolis Quality of Life child form (MMQL-UK (CF)) and to determine the level of association between the child and parent versions of this form. Methods This study was undertaken concurrently with the anglicisation and validation of the MMQL, a measure of HRQL developed for use with children in North America. At that time, no parent version existed, so the MMQL form for children (MMQL-UK (CF)) was used as the basis for the development of the MMQL-UK parent form (PF). The sample included a control group of healthy children and their parents and five exemplar groups; children diagnosed with asthma, diabetes or inflammatory bowel disease and their parents, children in remission from cancer and their parents and children in public care and their carers. Consistency of the MMQL-UK (PF) components were assessed by calculating Cronbach's alpha. Validation of the parent questionnaire was undertaken by comparing MMQL-UK (PF) component scores with comparable components on the proxy PedsQL™ quality of life scales, comparing MMQL-UK (PF) component scores between parents of healthy and chronic disease children and by comparison of component scores from children and their parents or carers. Reproducibility and responsiveness were assessed by retesting parents by follow-up questionnaires. Results A total of 874 children (completing MMQL-UK (CF)) and 572 parents or carers (completing MMQL-UK (PF)) took part in the study. The internal consistency of all the MMQL-UK (PF) components exceeding the accepted criterion of 0.70 and the construct validity was good with moderate correlations being evident between comparable components of the MMQL-UK (PF) and the proxy PedsQL™. Discriminant validity was demonstrated with significant differences being identified between parents of healthy children and those with chronic conditions. Intra-class correlations exceeded 0.65 for all MMQL-UK (PF) components demonstrating good reproducibility. Weak to moderate levels of responsiveness were demonstrated for all but social functioning. The MMQL-UK (PF) showed moderate parent-child correlation with the MMQL-UK (CF) for all components. The best correlations were seen for those components measuring the same construct (Pearson's r ranged from 0.31 to 0.61, p < 0.01 for equivalent components). Conclusion The MMQL-UK (PF) showed moderate to good correlations with the MMQL-UK (CF) component scores. The MMQL-UK (PF) will be of use when comparing child and parent/carer perception of the impact of a child's condition on their HRQL or where the child is too ill or young to provide their own report.
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Thesis (Ph.D.)--University of Washington, 2015
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Sweroside, a major active iridoid in Swertia pseudochinensis Hara, is recognized as an effective agent in the treatment of liver injury. Based on previous reports, the relatively short half-life (64 min) and poor bioavailability (approximately 0.31%) in rats suggested that not only sweroside itself but also its metabolites could be responsible for the observed hepato-protective effect. However, few studies have been carried out on the metabolism of sweroside. Therefore, the present study aimed at identifying the metabolites of sweroside in rat urine after a single oral dose (100 mg/kg). With ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), the metabolic profile revealed 11 metabolites in rat urine, including phase I, phase II and aglycone-related products. The chemical structures of metabolites were proposed based on accurate mass measurements of protonated or deprotonated molecules and their fragmentation patterns. Our findings showed that the aglycone of sweroside (M05) and its glucuronide conjugate (M06) were principal circulating metabolites in rats. While several other metabolic transformations, occurring via reduction, N-heterocyclization and N-acetylation after deglycosylation, were also observed. Two metabolites (M05 and M06) were isolated from the rat urine for structural elucidation and identifcation of reaction sites. Both M05 and M06 were characterized by 1H, 13C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. UHPLC/Q-TOF-MS analysis has provided an important analytical platform to gather metabolic profile of sweroside.
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The move into higher education is a real challenge for students from all educational backgrounds, with the adaptation to a new curriculum and style of learning and teaching posing a daunting task. A series of exercises were planned to boost the impact of the mathematics support for level four students and was focussed around a core module for all students. The intention was to develop greater confidence in tackling mathematical problems in all levels of ability and to provide more structured transition period in the first semester of level 4. Over a two-year period the teaching team for Biochemistry and Molecular Biology provided a series of structured formative tutorials and “interactive” online problems. Video solutions to all formative problems were made available, in order that students were able to engage with the problems at any time and were not disadvantaged if they could not attend. The formative problems were specifically set to dovetail into a practical report in which the mathematical skills developed were specifically assessed. Students overwhelmingly agreed that the structured formative activities had broadened their understanding of the subject and that more such activities would help. Furthermore, it is interesting to note that the package of changes undertaken resulted in a significant increase in the overall module mark over the two years of development.
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A large part of power dissipation in a system is generated by I/O devices. Increasingly these devices provide power saving mechanisms, inter alia to enhance battery life. While I/O device scheduling has been studied in the past for realtime systems, the use of energy resources by these scheduling algorithms may be improved. These approaches are crafted considering a very large overhead of device transitions. Technology enhancements have allowed the hardware vendors to reduce the device transition overhead and energy consumption. We propose an intra-task device scheduling algorithm for real time systems that allows to shut-down devices while ensuring system schedulability. Our results show an energy gain of up to 90% when compared to the techniques proposed in the state-of-the-art.
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Smartphones and other internet enabled devices are now common on our everyday life, thus unsurprisingly a current trend is to adapt desktop PC applications to execute on them. However, since most of these applications have quality of service (QoS) requirements, their execution on resource-constrained mobile devices presents several challenges. One solution to support more stringent applications is to offload some of the applications’ services to surrogate devices nearby. Therefore, in this paper, we propose an adaptable offloading mechanism which takes into account the QoS requirements of the application being executed (particularly its real-time requirements), whilst allowing offloading services to several surrogate nodes. We also present how the proposed computing model can be implemented in an Android environment
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Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic and health aspects of the human life. Surface temperature time-series characterise Earth as a slow dynamics spatiotemporal system, evidencing long memory behaviour, typical of fractional order systems. Such phenomena are difficult to model and analyse, demanding for alternative approaches. This paper studies the complex correlations between global temperature time-series using the Multidimensional scaling (MDS) approach. MDS provides a graphical representation of the pattern of climatic similarities between regions around the globe. The similarities are quantified through two mathematical indices that correlate the monthly average temperatures observed in meteorological stations, over a given period of time. Furthermore, time dynamics is analysed by performing the MDS analysis over slices sampling the time series. MDS generates maps describing the stations’ locus in the perspective that, if they are perceived to be similar to each other, then they are placed on the map forming clusters. We show that MDS provides an intuitive and useful visual representation of the complex relationships that are present among temperature time-series, which are not perceived on traditional geographic maps. Moreover, MDS avoids sensitivity to the irregular distribution density of the meteorological stations.
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INTRODUCTION AND OBJECTIVES: Recurrent syncope has a significant impact on quality of life. The development of measurement scales to assess this impact that are easy to use in clinical settings is crucial. The objective of the present study is a preliminary validation of the Impact of Syncope on Quality of Life questionnaire for the Portuguese population. METHODS: The instrument underwent a process of translation, validation, analysis of cultural appropriateness and cognitive debriefing. A population of 39 patients with a history of recurrent syncope (>1 year) who underwent tilt testing, aged 52.1 ± 16.4 years (21-83), 43.5% male, most in active employment (n=18) or retired (n=13), constituted a convenience sample. The resulting Portuguese version is similar to the original, with 12 items in a single aggregate score, and underwent statistical validation, with assessment of reliability, validity and stability over time. RESULTS: With regard to reliability, the internal consistency of the scale is 0.9. Assessment of convergent and discriminant validity showed statistically significant results (p<0.01). Regarding stability over time, a test-retest of this instrument at six months after tilt testing with 22 patients of the sample who had not undergone any clinical intervention found no statistically significant changes in quality of life. CONCLUSIONS: The results indicate that this instrument is of value for assessing quality of life in patients with recurrent syncope in Portugal.
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Hatching is an important niche shift, and embryos in a wide range of taxa can either accelerate or delay this life-history switch in order to avoid stage-specific risks. Such behavior can occur in response to stress itself and to chemical cues that allow anticipation of stress. We studied the genetic organization of this phenotypic plasticity and tested whether there are differences among populations and across environments in order to learn more about the evolutionary potential of stress-induced hatching. As a study species, we chose the brown trout (Salmo trutta; Salmonidae). Gametes were collected from five natural populations (within one river network) and used for full-factorial in vitro fertilizations. The resulting embryos were either directly infected with Pseudomonas fluorescens or were exposed to waterborne cues from P. fluorescens-infected conspecifics. We found that direct inoculation with P. fluorescens increased embryonic mortality and induced hatching in all host populations. Exposure to waterborne cues revealed population-specific responses. We found significant additive genetic variation for hatching time, and genetic variation in trait plasticity. In conclusion, hatching is induced in response to infection and can be affected by waterborne cues of infection, but populations and families differ in their reaction to the latter.
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PURPOSE: In obesity prevention, understanding psychosocial influences in early life is pivotal. Reviews reported contradictory results and a lack of longitudinal studies focusing on underlying lifestyle factors. This study tested whether psychosocial Quality-Of-Life (QOL) was associated with pre-schoolers' lifestyle and adiposity changes over one school year and whether lifestyle moderated the latter. It was hypothesised that QOL might not impact adiposity in everybody but that this might depend on preceding lifestyle. METHOD: Longitudinal data from 291 Swiss pre-schoolers (initially 3.9-6.3 years) was available. The following measures were used in longitudinal regressions: psychosocial QOL by PedsQL, adiposity (BMI z-score, waist, fat%), diet (food frequency), sedentary time and accelerometer-based activity. RESULTS: Concerning lifestyle, low psychosocial QOL was only related to unfavourable changes in diet (less fruit β = 0.21 and more fat intake β = -0.28) and lower physical activity (β = 0.21). Longitudinal QOL-adiposity relations appeared only after moderation by lifestyle factors (beta-range 0.13-0.67). Low psychosocial QOL was associated with increased adiposity in children with an unhealthy diet intake or high sedentary time. By contrast, low psychosocial QOL was associated with decreasing adiposity in high fruit consumers or more physically active pre-schoolers. CONCLUSION: Results emphasise the need for testing moderation in the QOL-adiposity relation. An unhealthy diet can be a vulnerability factor and high physical activity a protective factor in QOL-related adiposity. Consequently, QOL and lifestyle should be targeted concurrently in multi-factorial obesity prevention. The environment should be an 'activity encouraging, healthy food zone' that minimises opportunities for stress-induced eating. In addition, appropriate stress coping skills should be acquired.
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This study addressed the problem of the quality of life in the Brock Master of Education program. Survey and interview data were used to gain an understanding of satisfaction with the learning achieved and student life experienced. Eighty-seven percent of the study sample reported satisfaction with the program overall. Results suggested the higher the overall satisfaction with a program, the greater the likelihood learning and student life satisfaction were also more positive. Student reflections suggested satisfaction with the quality of life in the program was associated with the program's focus on the student, the use of self-directed learning, and the support of professors to meet student needs. Comparison of the Brock Master of Education survey with the Brock Pre-Service Teacher Education program showed both student groups shared a similar satisfaction with student life in the Faculty. Comparison of Master of Education programs suggested the difference between two programs, a difference which may be influenced by time in the program. The results from the three programs suggested that students beyond the first undergraduate degree favored the school domains of learning acquisition. Supplementary data on the relationship between cognitive and affective opinions suggested the more positive the affective dimension of learning, the greater the likelihood the cognitive dimensions of student life were also more positive. It was concluded that time was a chief factor influencing part-time student satisfaction with both learning and student life in the program. Part-time students, as. the majority in the survey, expressed comments about the need for clarity of communication between the organization and student to promote the effective use of limited time.
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In the field, mosquitoes characteristically feed on sugars soon after emergence and intermittently during their adult lives. Sugar meals are commonly derived from plant nectar and homopteran honeydew, and without them, adults can only survive for a few days on larval reserves. In addition to sugar, females of most species rely on blood for the initiation and maintenance of egg development; thus their reproductive success depends to some extent on the availability of blood hosts. Males, on the other hand, feed exclusively on sugars. Consequently, their sexual maturation and reproductive success is largely dependent upon access to sugar sources. Plant nectar and homopteran honeydew are the two main sugar sources utilized by mosquitoes in the wild. Previous laboratory studies had shown that differences between nectar sources can affect the survivorship and biting frequency of disease vectoring mosquitoes. However, little is known on how sugar composition influence the reproductive processes in male mosquitoes. Male mosquitoes transfer accessory gland proteins and other hormones to their mates along with sperm during mating. In the female, these seminal fluid constituents exert their influence on reproductive genes that control ovulation and vitellogenesis. The present study tests the hypothesis that the mates of males consuming different sugar meals will exhibit varying levels of induction of vitellogenin (a gene which regulates the expression of egg yolk precursor proteins). Real-time quantitative RT-PCR was used to investigate how each sugar meal indirectly influences vitellogenin mRNA abundance in female Anopheles stephensi following mating. Results indicate that mates of nectar-fed males exhibit 2-fold greater change in vitellogenin expression than the mates of honeydew-fed males. However, this response did not occur in non-blood fed controls. These findings suggest that the stimulatory effect of mating on vitellogenesis in blood meal-reliant (i.e. anautogenous) mosquitoes may only be synergistic in nature. The present study also sought to compare the potential fitness costs of mating incurred by females that do not necessarily require a blood meal to initiate a reproductive cycle (i.e., exhibit autogeny). Females of the facultatively autogenous mosquito, Culex molestus were allowed to mate with males sustained on either nectar or honedyew. Mean lifetime fecundity and survivorship of females under the two different mating regimes were then recorded. Additionally, one-dimensional gel electrophoresis was used to verify the transfer of male accessory gland proteins to the sperm storage organs of females during mating.While there was no significant difference in survival between the test treatments, the mates of nectar-fed males produced 11% more eggs on average than mates of honeydew-fed males. However, additional data are needed to justify the extrapolation of these findings to natural settings. These findings prompt further investigation as the differences caused by diet variation in males may be reflected across other life history traits such as mating frequency and insemination capacity.