University of Victoria

About: University of Victoria is a education organization based out in Victoria, British Columbia, Canada. It is known for research contribution in the topics: Population & Galaxy. The organization has 14994 authors who have published 41051 publications receiving 1447972 citations. The organization is also known as: Victoria College.

The nature and space density of fossil groups of galaxies

Abstract: We describe the properties of a sample of galaxy groups with very unusual distributions of galaxy luminosities. The most extreme example has an X-ray luminosity similar to that of the Virgo cluster but has a very low richness, with only one galaxy brighter than L*, compared with six in Virgo. That one galaxy, however, is optically more luminous than any galaxy in Virgo and has an optical luminosity as bright as many of the central cD galaxies in rich Abell clusters. The characteristic feature of the fossil groups we study is that most of the light arises from one dominant, central galaxy. We define a fossil system and, based on this definition, construct a small X-ray-selected, flux-limited sample of fossil groups with well-known selection criteria. We confirm that these systems are indeed groups of galaxies, but dominated by one central luminous giant elliptical galaxy and with few, or no, L* galaxies. We find that fossil systems represent 8–20 per cent of all systems of the same X-ray luminosity. Fossil groups are at least as numerous as all poor and rich clusters combined, and are thus a possible site for the formation of luminous central cluster galaxies before infall into clusters occurs. The fossil systems in our sample have significantly higher X-ray luminosities than normal groups of similar total optical luminosities (or similar X-ray temperature, where the latter can be measured). These enhanced X-ray luminosities may be due to relatively cool gas in the innermost regions or due to a low central gas entropy. We interpret fossil groups as old, undisturbed systems which have avoided infall into clusters, but where galaxy merging of most of the L* galaxies has occurred. An early formation epoch, before that of most groups, could explain low central gas entropies and high X-ray luminosities.

A Review and Meta-Analysis of Affective Judgments and Physical Activity in Adult Populations

Abstract: Popular theories of health behavior have often been criticized for neglecting an affective component to behavioral engagement. This study reviewed affective judgment (AJ) constructs employed in physical activity research to assess the relationship with behavior. Studies were eligible if they included: (a) a measure of physical activity; (b) a distinct measure of AJ (e.g., affective attitude, enjoyment, intrinsic motivation); and (c) involved participants with a mean age of 18 years or older. Literature searches were concluded in September, 2009 among five key search engines. This search yielded a total of 10,631 potentially relevant records; of these, 102 passed the eligibility criteria. Random effects meta-analysis procedures with correction for sampling and measurement bias were employed in the analysis. Articles were published between 1989 and 2009, with sample sizes ranging from 15 to 6,739. Of the studies included, 82 were correlational and 20 were experimental, yielding 114 independent samples. The majority of the correlational samples reported a significant positive correlation between AJ and physical activity (83 out of 85), with a summary r of 0.42 (95% CI 0.37 to 0.46) that was invariant across the measures employed, study quality, population sampled and cultural variables. Experimental studies demonstrated that persuasive, information-based, and self-regulatory interventions failed to change AJ; by contrast, environmental and experiential interventions showed promise in their capability to influence AJ. The results point to a medium-effect size relationship between AJ and physical activity. Interventions that change AJ are scarce despite their potential for changing physical activity. Future experimental work designed to evaluate the causal impact of AJ on physical activity is required.

Burden and Well-Being Among Caregivers: Examining the Distinction

Abstract: Purpose: This study assessed overall quality of life of caregivers, using a path model in which burden was conceptualized as distinct from well-being. Design and Methods: Data were drawn from a representative sample of caregivers to dementia and nondementia care receivers in British Columbia, Canada ( N � 243). The model used was based on a previously proposed stress/appraisal path model and used multiple regression path estimates. Primary stressors were care receiver cognitive status, physical function, and behavioral problems; the primary appraisal variable was hours of caregiving during the previous week. Mediators were perceived social support, frequency of getting a break, and hours of formal service use; secondary appraisal was subjective burden. The outcome measure was generalized well-being. Results: Well-being was directly affected by four variables: perceived social support, burden, self-esteem, and hours of informal care. Burden was affected directly by behavioral problems, frequency of getting a break, self-esteem, and informal hours of care and was not affected by perceived social support. Discussion: The finding that perceived social support is strongly related to well-being but unrelated to burden reinforces the conceptual distinctiveness of the latter two concepts. This suggests that quality of life of caregivers could be improved even with burden in their lives and that the overwhelming focus in caregiving research on burden should be supplemented with an emphasis on quality of life.

Energy investment needs for fulfilling the Paris Agreement and achieving the sustainable development goals

Abstract: Low-carbon investments are necessary for driving the energy system transformation that is called for by both the Paris Agreement and Sustainable Development Goals. Improving understanding of the scale and nature of these investments under diverging technology and policy futures is therefore of great importance to decision makers. Here, using six global modelling frameworks, we show that the pronounced reallocation of the investment portfolio required to transform the energy system will not be initiated by the current suite of countries’ Nationally Determined Contributions. Charting a course toward ‘well below 2 °C’ instead sees low-carbon investments overtaking fossil investments globally by around 2025 or before and growing thereafter. Pursuing the 1.5 °C target demands a marked upscaling in low-carbon capital beyond that of a 2 °C-consistent future. Actions consistent with an energy transformation would increase the costs of achieving the goals of energy access and food security, but reduce the costs of achieving air-quality goals. The scale and nature of energy investments under diverging technology and policy futures is of great importance to decision makers. Here, a multi-model study projects investment needs under countries’ nationally determined contributions and in pathways consistent with achieving the 2 °C and 1.5 °C targets as well as certain SDGs.

Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector

Abstract: Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy of 13 TeV collected in 2015 and 2016 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons (e or μ). Several signal regions are considered with increasing requirements on the missing transverse momentum above 250 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.