1000 resultados para supernovae: individual: PS1-10pm


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We here explore the effects of the SN explosions into the halo of star-forming galaxies like the Milky Way. Successive randomly distributed and clustered SNe explosions cause the formation of hot superbubbles that drive either fountains or galactic winds above the galactic disk, depending on the amount and concentration of energy that is injected by the SNe. In a galactic fountain, the ejected gas is re-captured by the gravitational potential and falls back onto the disk. From 3D non-equilibrium radiative cooling hydrodynamical simulations of these fountains, we find that they may reach altitudes up to about 5 kpc in the halo and thus allow for the formation of the so called intermediate-velocity-clouds (IVCs) which are often observed in the halos of disk galaxies. The high-velocity-clouds that are also observed but at higher altitudes (of up to 12 kpc) require another mechanism to explain their production. We argue that they could be formed either by the capture of gas from the intergalactic medium and/or by the action of magnetic fields that are carried to the halo with the gas in the fountains. Due to angular momentum losses to the halo, we find that the fountain material falls back to smaller radii and is not largely spread over the galactic disk. Instead, the SNe ejecta fall nearby the region where the fountain was produced, a result which is consistent with recent chemical models of the galaxy. The fall back material leads to the formation of new generations of molecular clouds and to supersonic turbulence feedback in the disk. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.

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Many generalist populations may actually be composed of relatively specialist individuals. This `individual specialization` may have important ecological and evolutionary implications. Although this phenomenon has been documented in more than one hundred taxa, it is still unclear how individuals within a population actually partition resources. Here we applied several methods based on network theory to investigate the intrapopulation patterns of resource use in the gracile mouse opossum Gracilinanus microtarsus. We found evidence of significant individual specialization in this species and that the diets of specialists are nested within the diets of generalists. This novel pattern is consistent with a recently proposed model of optimal foraging and implies strong asymmetry in the interactions among individuals of a population.

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P>1. Much of the current understanding of ecological systems is based on theory that does not explicitly take into account individual variation within natural populations. However, individuals may show substantial variation in resource use. This variation in turn may be translated into topological properties of networks that depict interactions among individuals and the food resources they consume (individual-resource networks). 2. Different models derived from optimal diet theory (ODT) predict highly distinct patterns of trophic interactions at the individual level that should translate into distinct network topologies. As a consequence, individual-resource networks can be useful tools in revealing the incidence of different patterns of resource use by individuals and suggesting their mechanistic basis. 3. In the present study, using data from several dietary studies, we assembled individual-resource networks of 10 vertebrate species, previously reported to show interindividual diet variation, and used a network-based approach to investigate their structure. 4. We found significant nestedness, but no modularity, in all empirical networks, indicating that (i) these populations are composed of both opportunistic and selective individuals and (ii) the diets of the latter are ordered as predictable subsets of the diets of the more opportunistic individuals. 5. Nested patterns are a common feature of species networks, and our results extend its generality to trophic interactions at the individual level. This pattern is consistent with a recently proposed ODT model, in which individuals show similar rank preferences but differ in their acceptance rate for alternative resources. Our findings therefore suggest a common mechanism underlying interindividual variation in resource use in disparate taxa.

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The eigenvalue densities of two random matrix ensembles, the Wigner Gaussian matrices and the Wishart covariant matrices, are decomposed in the contributions of each individual eigenvalue distribution. It is shown that the fluctuations of all eigenvalues, for medium matrix sizes, are described with a good precision by nearly normal distributions.

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At the end of 2005, the State Council of China passed ”The Decision on adjusting the Individual Account of Basic Pension System”, which adjusted the individual account in the 1997 basic pension system. In this essay, we will analyze the adjustment above, and use Life Annuity Actuarial Theory to establish the basic pension substitution rate model. Monte Carlo simulation is also used to prove the rationality of the model. Some suggestions are put forward associated with the substitution rate according to the current policy.

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Background: In Sweden, midwives play prominent supportive role in antenatal care by counselling and promoting healthy lifestyles. This study aimed to explore how Swedish midwives experience the counselling of pregnant women on physical activity, specifically focusing on facilitators and barriers during pregnancy. Also, addressing whether the midwives perceive that their own lifestyle and body shape may influence the content of the counselling they provide. Methods: Eight focus group discussions (FGD) were conducted with 41 midwives working in antenatal care clinics in different parts of Sweden between September 2013 and January 2014. Purposive sampling was applied to ensure a variation in age, work experience, and geographical location. The FGD were digitally recorded, transcribed verbatim, and analyzed using manifest and latent content analysis. Results: The main theme- "An on-going individual adjustment" was built on three categories: "Counselling as a challenge"; "Counselling as walking the thin ice" and "Counselling as an opportunity" reflecting the midwives on-going need to adjust their counselling depending on each woman's specific situation. Furthermore, counselling pregnant women on physical activity was experienced as complex and ambiguous, presenting challenges as well as opportunities. When midwives challenged barriers to physical activity, they risked being rejected by the pregnant women. Despite risking rejection, the midwives tried to promote increased physical activity based on their assessment of individual needs of the pregnant woman. Some participants felt that their own lifestyle and body shape might negatively influence the counselling; however, the majority of participants did not agree with this perspective. Conclusions: Counselling on physical activity during pregnancy may be a challenging task for midwives, characterized by on-going adjustments based on a pregnant woman's individual needs. Midwives strive to find individual solutions to encourage physical activity. However, to improve their counselling, midwives may benefit from further training, also organizational and financial barriers need to be addressed. Such efforts might result in improved opportunities to further support pregnant women's motivation for performance of physical activity.

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The societal changes in India and the available variety of reproductive health services call for evidence to inform health systems how to satisfy young women's reproductive health needs. Inspired by Foucault's power idiom and Bandura's agency framework, we explore young women's opportunities to practice reproductive agency in the context of collective social expectations. We carried out in-depth interviews with 19 young women in rural Rajasthan. Our findings highlight how changes in notions of agency across generations enable young women's reproductive intentions and desires, and call for effective means of reproductive control. However, the taboo around sex without the intention to reproduce made contraceptive use unfeasible. Instead, abortions were the preferred method for reproductive control. In conclusion, safe abortion is key, along with the need to address the taboo around sex to enable use of "modern" contraception. This approach could prevent unintended pregnancies and expand young women's agency.

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Background. Nurses' research utilization (RU) as part of evidence-based practice is strongly emphasized in today's nursing education and clinical practice. The primary aim of RU is to provide high-quality nursing care to patients. Data on newly graduated nurses' RU are scarce, but a predominance of low use has been reported in recent studies. Factors associated with nurses' RU have previously been identified among individual and organizational/contextual factors, but there is a lack of knowledge about how these factors, including educational ones, interact with each other and with RU, particularly in nurses during the first years after graduation. The purpose of this study was therefore to identify factors that predict the probability for low RU among registered nurses two years after graduation. Methods. Data were collected as part of the LANE study (Longitudinal Analysis of Nursing Education), a Swedish national survey of nursing students and registered nurses. Data on nurses' instrumental, conceptual, and persuasive RU were collected two years after graduation (2007, n = 845), together with data on work contextual factors. Data on individual and educational factors were collected in the first year (2002) and last term of education (2004). Guided by an analytic schedule, bivariate analyses, followed by logistic regression modeling, were applied. Results. Of the variables associated with RU in the bivariate analyses, six were found to be significantly related to low RU in the final logistic regression model: work in the psychiatric setting, role ambiguity, sufficient staffing, low work challenge, being male, and low student activity. Conclusions. A number of factors associated with nurses' low extent of RU two years postgraduation were found, most of them potentially modifiable. These findings illustrate the multitude of factors related to low RU extent and take their interrelationships into account. This knowledge might serve as useful input in planning future studies aiming to improve nurses', specifically newly graduated nurses', RU.

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Embodied energy (EE) analysis has become an important area of energy research, in attempting to trace the direct and indirect energy requirements of products and services throughout their supply chain. Typically, input-output (I-O) models have been used to calculate EE because they are considered to be comprehensive in their analysis. However, a major deficiency of using I-O models is that they have inherent errors and therefore cannot be reliably applied to individual cases. Thus, there is a need for the ability to disaggregate an I-O model into its most important 'energy paths', for the purpose of integrating case-specific data. This paper presents a new hybrid method for conducting EE analyses for individual buildings, which retains the completeness of the I-O model. This new method is demonstrated by application to an Australian residential building. Only 52% of the energy paths derived from the I-O model were substituted using case-specific data. This indicates that previous system boundaries for EE studies of individual residential buildings are less than optimal. It is envisaged that the proposed method will provide construction professionals with more accurate and reliable data for conducting life cycle energy analysis of buildings. Furthermore, by analysing the unmodified energy paths, further data collection can be prioritized effectively.

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This study examined whether age, gender, intelligence, communication ability and shyness predict intellectually disabled children’s susceptibility to an interviewer’s misleading suggestions. Further, the study examined whether the relative influence of these factors differs between intellectually disabled and mainstream samples. Participants included 75 children with mild and borderline intellectual disabilities (aged 77–158 months) and 83 mainstream children (aged 68–152 months). All children were individually administered the Yield and Shift subscales of the Gudjonsson Suggestibility Scale (Form 2) as well as standardised measures of IQ, shyness and communication ability. For the intellectually disabled children, multiple regression analyses revealed that age, IQ and communication inversely predicted Yield suggestibility, however, none of the factors predicted Shift suggestibility. For the mainstream children, age made a significant independent contribution to both Yield and Shift suggestibility, while IQ was a significant predictor of Shift suggestibility. When comparing the relative impact of these factors across the samples, age had a significantly greater impact on mainstream (compared with intellectually disabled) children’s Shift suggestibility, while IQ had a significantly greater influence on intellectually disabled (compared with mainstream) children’s Yield scores. These findings highlight the limited generalisability of previous findings involving mainstream children’s suggestibility to intellectually disabled samples.


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The study examined the role of body dissatisfaction, body image importance, sociocultural influences (media and parent and peer encouragement), self-esteem and negative affect on body change strategies to decrease weight and increase muscles in adolescent boys and girls. Surveys were administered to 587 boys and 598 girls aged between 11 and 15 years. For both genders, parent and peer encouragement and negative affect were the primary predictors of body dissatisfaction, body image importance and strategies to decrease weight and increase muscles. In addition, body image importance was a significant factor in the development of both types of body change strategies, while the media only predicted strategies to decrease weight. Lastly, the effects of self-esteem were mediated by body dissatisfaction. For boys, a stronger focus on body importance occurred among the boys who were generally satisfied with their bodies while the reverse was the case for girls.

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In this article it is contended that state practice, as evidenced in the  declarations of the judiciary and the many treaties and conventions  guaranteeing human rights, reveals a consensus of opinion acknowledging the individual to be an international juristic entity. So extensive is this practice that it could be seen as marking the emergence of a new customary international norm; or at least a general principle of international law, yet to crystallise into a custom; acknowledging the individual as the beneficiary of international rights. This is important for individuals and minority groups because if they possess international rights independently of the State, enforcement of their rights will no longer depend on the interests of the State. Where the State is often the offender of human rights, international law will not effectively confer any real rights unless the individual is so recognised as an international juristic entity.

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This paper focuses on Information and Communication Technology (ICT) academics' perceptions of factors that promote and inhibit their pursuit of scholarship in their teaching work. It identifies critical factors that influence academics' attitudes, orientations and behaviours in respect to the scholarship of teaching, and from these builds a framework for understanding the interaction between these factors. We have named this framework the Scholarship of Teaching Support Framework.

During 2001 and 2002 a national project investigated teaching and learning initiatives in the major discipline of lCT in Australia's universities. As part of this project a mini-conference program was devised to elicit academics' perceptions of the factors influencing their teaching work and their participation in scholarly activities around this work. In total 83 ICT teachers from 29 universities participated in the mini-conference program. Attendees included staff members from a range of academic levels.

In discussions of aspects of the scholarship of teaching at the mini-conference participants referred to both attributes and responses of both university teachers and the university institutions. We have categorized these factors into those that relate to the individual academic (Individual domain) and those that relate to the tertiary institutional system (Organisational domain). Many contributions highlighted the interaction between these two domains.

Within the Individual domain, two key factors described by participants as affecting the pursuit of the scholarship of teaching were teachers' motivation towards, and their capabilities in, scholarly activities surrounding their teaching. Within the organizational domain two influential factors also emerged. These were the organizational support provided through allocation of resources and symbolic support reflected in an institution's systems, policies and processes.

Our findings indicate that both the Individual and Organizational domains contribute to university teachers' decisions to pursue (or not to pursue) the scholarship of teaching.

These two domains were seen by participants to interact within university environments to influence whether a particular environment is supportive or unsupportive in terms of the pursuit of the scholarship of teaching. Factors both from and within the individual and the organizational domains were seen to interact with each other forming a web of interrelated factors that appear to influence individuals' decisions to pursue, or not to pursue, the scholarship of teaching. From this complexity four theoretical extremes emerged providing the dimensions and components of the Scholarship of Teaching Support Framework.

We argue that responsive and innovative approaches to university teaching are best supported by academics undertaking scholarly activities around their teaching work, yet this article presents a picture of a university work environment where scholarly activities that focus on teaching and learning are seen as generally unsupported and unrewarded. This perception was identified as commonalities across a university system. Although some exceptions were noted, participants generally agreed that the organisational domain of Australian universities was largely unsupportive of the pursuit of the scholarship of teaching. Similarly, in general, university ICT teachers were not thought to have the backgrounds and capabilities necessary for pursuing the scholarship of teaching, such as familiarity with literature on teaching and learning and skills in educational evaluation. However, despite perceived inhibitors in universities' organisational culture and allocation of resources, and a perceived lack in individuals' skills, participants agreed that scholarly activities and innovation in university teaching and learning do take place, These are largely driven by the intrinsic motivation of individuals. It was recognised that further work is necessary to explore how motivation can be engendered and encouraged.

The Scholarship of Teaching Support Framework is a useful tool for examining how conducive a given university teaching context is to the scholarship of teaching and, therefore, can be used for review purposes within both research and policy contexts. Such tools will become increasingly important as policy changes begin to affect practices in how university teaching work is managed, supported and encouraged.