920 resultados para angular displacement


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The effects of small changes in flight-path parameters (primary and secondary flight paths, detector angles), and of displacement of the sample along the beam axis away from its ideal position, are examined for an inelastic time-of-flight (TOF) neutron spectrometer, emphasising the deep-inelastic regime. The aim was to develop a rational basis for deciding what measured shifts in the positions of spectral peaks could be regarded as reliable in the light of the uncertainties in the calibrated flight-path parameters. Uncertainty in the length of the primary or secondary flight path has the least effect on the positions of the peaks of H, D and He, which are dominated by the accuracy of the calibration of the detector angles. This aspect of the calibration of a TOF spectrometer therefore demands close attention to achieve reliable outcomes where the position of the peaks is of significant scientific interest and is discussed in detail. The corresponding sensitivities of the position of peak of the Compton profile, J(y), to flight-path parameters and sample position are also examined, focusing on the comparability across experiments of results for H, D and He. We show that positioning the sample to within a few mm of the ideal position is required to ensure good comparability between experiments if data from detectors at high forward angles are to be reliably interpreted.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Executive Summary The Australian Psychological Society categorically condemns the practice of detaining child asylum seekers and their families, on the grounds that it is not commensurate with psychological best practice concerning children’s development and mental health and wellbeing. Detention of children in this fashion is also arguably a violation of the UN Convention on the Rights of the Child. A thorough review of relevant psychological theory and available research findings from international research has led the Australian Psychological Society to conclude that: • Detention is a negative socialisation experience. • Detention is accentuates developmental risks. • Detention threatens the bonds between children and significant caregivers. • Detention limits educational opportunities. • Detention has traumatic impacts on children of asylum seekers. • Detention reduces children’s potential to recover from trauma. • Detention exacerbates the impacts of other traumas. • Detention of children from these families in many respects is worse for them than being imprisoned. In the absence of any indication from the Australian Government that it intends in the near future to alter the practice of holding children in immigration detention, the Australian Psychological Society’s intermediate position is that the facilitation of short-term and long-term psychological development and wellbeing of children is the basic tenet upon which detention centres should be audited and judged. Based on that position, the Society has identified a series of questions and concerns that arise directly from the various psychological perspectives that have been brought to bear on estimating the effects of detention on child asylum seekers. The Society argues that, because these questions and concerns relate specifically to improvement and maintenance of child detainees’ educational, social and psychological wellbeing, they are legitimate matters for the Inquiry to consider and investigate. • What steps are currently being taken to monitor the psyc hological welfare of the children in detention? In particular, what steps are being taken to monitor the psychological wellbeing of children arriving from war-torn countries? • What qualifications and training do staff who care for children and their families in detention centres have? What knowledge do they have of psychological issues faced by people who have been subjected to traumatic experiences and are suffering high degrees of anxiety, stress and uncertainty? • What provisions have been made for psycho-educational assessment of children’s specific learning needs prior to their attending formal educational programmes? • who are suffering chronic and/or vicarious trauma as a result of witnessing threatening behaviour whilst in detention? • What provisions have been made for families who have been seriously affected by displacement to participate in family therapy? • What critical incident debriefing procedures are in place for children who have witnessed their parents, other family members, or social acquaintances engaging in acts of self-harm or being harmed while in detention? What psychotherapeutic support is in place for children who themselves have been harmed or have engaged in self- harmful acts while in detention? • What provisions are in place for parenting programmes that provide support for parents of children under extremely difficult psychological and physical circumstances? • What efforts are being made to provide parents with the opportunity to model traditional family roles for children, such as working to earn an income, meal preparation, other household duties, etc.? • What opportunities are in place for the assessment of safety issues such as bullying, and sexual or physical abuse of children or their mothers in detention centres? • How are resources distributed to children and families in detention centres? • What socialization opportunities are available either within detention centres or in the wider community for children to develop skills and independence, engage in social activities, participate in cultural traditions, and communicate and interaction with same-age peers and adults from similar ethnic and religious backgrounds? • What access do children and families have to videos, music and entertainment from their cultures of origin? • What provisions are in place to ensure the maintenance of privacy in a manner commensurate with usual cultural practice? • What is the Government’s rationale for continuing to implement a policy of mandatory detention of child asylum seekers that on the face of it is likely to have a pernicious impact on these children’s mental health? • In view of the evidence on the potential long-term impact of mandatory detention on children, what processes may be followed by Government to avoid such a practice and, more importantly, to develop policies and practices that will have a positive impact on these children’s psychological development and mental health?

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This literature review was developed as background for the formulation of an Australian Psychological Society position on the mental health and wellbeing of refugees resettling in Australia. The major aim is to provide a broad overview of the concerns related to refugee mental health and wellbeing within the Australian context. To begin, a brief overview of the definition of a refugee and the scope of refugee movement is provided. Next, the review examines the pre-displacement, post-displacement, systemic and socio-political factors that influence the process of adaptation in refugee resettlement. It then reviews documented approaches to psychological assessment and therapeutic interventions with refugees; and finally it summarises suggestions for assessment and intervention in these practice contexts.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The health impacts of exposure to ambient temperature have been drawing increasing attention from the environmental health research community, government, society, industries, and the public. Case-crossover and time series models are most commonly used to examine the effects of ambient temperature on mortality. However, some key methodological issues remain to be addressed. For example, few studies have used spatiotemporal models to assess the effects of spatial temperatures on mortality. Few studies have used a case-crossover design to examine the delayed (distributed lag) and non-linear relationship between temperature and mortality. Also, little evidence is available on the effects of temperature changes on mortality, and on differences in heat-related mortality over time. This thesis aimed to address the following research questions: 1. How to combine case-crossover design and distributed lag non-linear models? 2. Is there any significant difference in effect estimates between time series and spatiotemporal models? 3. How to assess the effects of temperature changes between neighbouring days on mortality? 4. Is there any change in temperature effects on mortality over time? To combine the case-crossover design and distributed lag non-linear model, datasets including deaths, and weather conditions (minimum temperature, mean temperature, maximum temperature, and relative humidity), and air pollution were acquired from Tianjin China, for the years 2005 to 2007. I demonstrated how to combine the case-crossover design with a distributed lag non-linear model. This allows the case-crossover design to estimate the non-linear and delayed effects of temperature whilst controlling for seasonality. There was consistent U-shaped relationship between temperature and mortality. Cold effects were delayed by 3 days, and persisted for 10 days. Hot effects were acute and lasted for three days, and were followed by mortality displacement for non-accidental, cardiopulmonary, and cardiovascular deaths. Mean temperature was a better predictor of mortality (based on model fit) than maximum or minimum temperature. It is still unclear whether spatiotemporal models using spatial temperature exposure produce better estimates of mortality risk compared with time series models that use a single site’s temperature or averaged temperature from a network of sites. Daily mortality data were obtained from 163 locations across Brisbane city, Australia from 2000 to 2004. Ordinary kriging was used to interpolate spatial temperatures across the city based on 19 monitoring sites. A spatiotemporal model was used to examine the impact of spatial temperature on mortality. A time series model was used to assess the effects of single site’s temperature, and averaged temperature from 3 monitoring sites on mortality. Squared Pearson scaled residuals were used to check the model fit. The results of this study show that even though spatiotemporal models gave a better model fit than time series models, spatiotemporal and time series models gave similar effect estimates. Time series analyses using temperature recorded from a single monitoring site or average temperature of multiple sites were equally good at estimating the association between temperature and mortality as compared with a spatiotemporal model. A time series Poisson regression model was used to estimate the association between temperature change and mortality in summer in Brisbane, Australia during 1996–2004 and Los Angeles, United States during 1987–2000. Temperature change was calculated by the current day's mean temperature minus the previous day's mean. In Brisbane, a drop of more than 3 �C in temperature between days was associated with relative risks (RRs) of 1.16 (95% confidence interval (CI): 1.02, 1.31) for non-external mortality (NEM), 1.19 (95% CI: 1.00, 1.41) for NEM in females, and 1.44 (95% CI: 1.10, 1.89) for NEM aged 65.74 years. An increase of more than 3 �C was associated with RRs of 1.35 (95% CI: 1.03, 1.77) for cardiovascular mortality and 1.67 (95% CI: 1.15, 2.43) for people aged < 65 years. In Los Angeles, only a drop of more than 3 �C was significantly associated with RRs of 1.13 (95% CI: 1.05, 1.22) for total NEM, 1.25 (95% CI: 1.13, 1.39) for cardiovascular mortality, and 1.25 (95% CI: 1.14, 1.39) for people aged . 75 years. In both cities, there were joint effects of temperature change and mean temperature on NEM. A change in temperature of more than 3 �C, whether positive or negative, has an adverse impact on mortality even after controlling for mean temperature. I examined the variation in the effects of high temperatures on elderly mortality (age . 75 years) by year, city and region for 83 large US cities between 1987 and 2000. High temperature days were defined as two or more consecutive days with temperatures above the 90th percentile for each city during each warm season (May 1 to September 30). The mortality risk for high temperatures was decomposed into: a "main effect" due to high temperatures using a distributed lag non-linear function, and an "added effect" due to consecutive high temperature days. I pooled yearly effects across regions and overall effects at both regional and national levels. The effects of high temperature (both main and added effects) on elderly mortality varied greatly by year, city and region. The years with higher heat-related mortality were often followed by those with relatively lower mortality. Understanding this variability in the effects of high temperatures is important for the development of heat-warning systems. In conclusion, this thesis makes contribution in several aspects. Case-crossover design was combined with distribute lag non-linear model to assess the effects of temperature on mortality in Tianjin. This makes the case-crossover design flexibly estimate the non-linear and delayed effects of temperature. Both extreme cold and high temperatures increased the risk of mortality in Tianjin. Time series model using single site’s temperature or averaged temperature from some sites can be used to examine the effects of temperature on mortality. Temperature change (no matter significant temperature drop or great temperature increase) increases the risk of mortality. The high temperature effect on mortality is highly variable from year to year.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Infection by dengue virus (DENV) is a major public health concern in hundreds of tropical and subtropical countries. French Polynesia (FP) regularly experiences epidemics that initiate, or are consecutive to, DENV circulation in other South Pacific Island Countries (SPICs). In January 2009, after a decade of serotype 1 (DENV-1) circulation, the first cases of DENV-4 infection were reported in FP. Two months later a new epidemic emerged, occurring about 20 years after the previous circulation of DENV-4 in FP. In this study, we investigated the epidemiological and molecular characteristics of the introduction, spread and genetic microevolution of DENV-4 in FP. METHODOLOGY/PRINCIPAL FINDINGS: Epidemiological data suggested that recent transmission of DENV-4 in FP started in the Leeward Islands and this serotype quickly displaced DENV-1 throughout FP. Phylogenetic analyses of the nucleotide sequences of the envelope (E) gene of 64 DENV-4 strains collected in FP in the 1980s and in 2009-2010, and some additional strains from other SPICs showed that DENV-4 strains from the SPICs were distributed into genotypes IIa and IIb. Recent FP strains were distributed into two clusters, each comprising viruses from other but distinct SPICs, suggesting that emergence of DENV-4 in FP in 2009 resulted from multiple introductions. Otherwise, we observed that almost all strains collected in the SPICs in the 1980s exhibit an amino acid (aa) substitution V287I within domain I of the E protein, and all recent South Pacific strains exhibit a T365I substitution within domain III. CONCLUSIONS/SIGNIFICANCE: This study confirmed the cyclic re-emergence and displacement of DENV serotypes in FP. Otherwise, our results showed that specific aa substitutions on the E protein were present on all DENV-4 strains circulating in SPICs. These substitutions probably acquired and subsequently conserved could reflect a founder effect to be associated with epidemiological, geographical, eco-biological and social specificities in SPICs.