7,148 research outputs found
Maximally extended, explicit and regular coverings of the Schwarzschild - de Sitter vacua in arbitrary dimension
Maximally extended, explicit and regular coverings of the Schwarzschild - de
Sitter family of vacua are given, first in spacetime (generalizing a result due
to Israel) and then for all dimensions (assuming a sphere). It is
shown that these coordinates offer important advantages over the well known
Kruskal - Szekeres procedure.Comment: 12 pages revtex4 5 figures in color. Higher resolution version at
http://www.astro.queensu.ca/~lake/regularcoordinates.pd
Globular Cluster Formation in the Virgo Cluster
Metal poor globular clusters (MPGCs) are a unique probe of the early
universe, in particular the reionization era. Systems of globular clusters in
galaxy clusters are particularly interesting as it is in the progenitors of
galaxy clusters that the earliest reionizing sources first formed. Although the
exact physical origin of globular clusters is still debated, it is generally
admitted that globular clusters form in early, rare dark matter peaks (Moore et
al. 2006; Boley et al. 2009). We provide a fully numerical analysis of the
Virgo cluster globular cluster system by identifying the present day globular
cluster system with exactly such early, rare dark matter peaks. A popular
hypothesis is that that the observed truncation of blue metal poor globular
cluster formation is due to reionization (Spitler et al. 2012; Boley et al.
2009; Brodie & Strader 2006); adopting this view, constraining the formation
epoch of MPGCs provides a complementary constraint on the epoch of
reionization. By analyzing both the line of sight velocity dispersion and the
surface density distribution of the present day distribution we are able to
constrain the redshift and mass of the dark matter peaks. We find and quantify
a dependence on the chosen line of sight of these quantities, whose strength
varies with redshift, and coupled with star formation efficiency arguments find
a best fitting formation mass and redshift of and . We predict intracluster MPGCs in
the Virgo cluster. Our results confirm the techniques pioneered by Moore et al.
(2006) when applied to the the Virgo cluster and extend and refine the analytic
results of Spitler et al. (2012) numerically.Comment: 13 Pages, 13 Figures, submitted to MNRA
Detection of zeptojoule microwave pulses using electrothermal feedback in proximity-induced Josephson junctions
We experimentally investigate and utilize electrothermal feedback in a
microwave nanobolometer based on a normal-metal
(\mbox{Au}_{x}\mbox{Pd}_{1-x}) nanowire with proximity-induced
superconductivity. The feedback couples the temperature and the electrical
degrees of freedom in the nanowire, which both absorbs the incoming microwave
radiation, and transduces the temperature change into a radio-frequency
electrical signal. We tune the feedback in situ and access both positive and
negative feedback regimes with rich nonlinear dynamics. In particular, strong
positive feedback leads to the emergence of two metastable electron temperature
states in the millikelvin range. We use these states for efficient threshold
detection of coherent 8.4 GHz microwave pulses containing approximately 200
photons on average, corresponding to 1.1 \mbox{ zJ} \approx 7.0 \mbox{ meV}
of energy
Food-borne disease and climate change in the United Kingdom
This review examined the likely impact of climate change upon food-borne disease in the UK using Campylobacter and Salmonella as example organisms. Campylobacter is an important food-borne disease and an increasing public health threat. There is a reasonable evidence base that the environment and weather play a role in its transmission to humans. However, uncertainty as to the precise mechanisms through which weather affects disease, make it difficult to assess the likely impact of climate change. There are strong positive associations between Salmonella cases and ambient temperature, and a clear understanding of the mechanisms behind this. However, because the incidence of Salmonella disease is declining in the UK, any climate change increases are likely to be small. For both Salmonella and Campylobacter the disease incidence is greatest in older adults and young children. There are many pathways through which climate change may affect food but only a few of these have been rigorously examined. This provides a high degree of uncertainty as to what the impacts of climate change will be. Food is highly controlled at the National and EU level. This provides the UK with resilience to climate change as well as potential to adapt to its consequences but it is unknown whether these are sufficient in the context of a changing climate
Static Ricci-flat 5-manifolds admitting the 2-sphere
We examine, in a purely geometrical way, static Ricci-flat 5-manifolds
admitting the 2-sphere and an additional hypersurface-orthogonal Killing
vector. These are widely studied in the literature, from different physical
approaches, and known variously as the Kramer - Gross - Perry - Davidson - Owen
solutions. The 2-fold infinity of cases that result are studied by way of new
coordinates (which are in most cases global) and the cases likely to be of
interest in any physical approach are distinguished on the basis of the
nakedness and geometrical mass of their associated singularities. It is argued
that the entire class of solutions has to be considered unstable about the
exceptional solutions: the black string and soliton cases. Any physical theory
which admits the non-exceptional solutions as the external vacuua of a
collapsing object has to accept the possibility of collapse to zero volume
leaving behind the weakest possible, albeit naked, geometrical singularities at
the origin.Finally, it is pointed out that these types of solutions generalize,
in a straightforward way, to higher dimensions.Comment: Generalize, in a straightforward way, to higher dimension
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Factors affecting the social and affiliative needs of people suffering from long-term mental health problems: a qualitative project comparing the social needs of people suffering from schizophrenia or depression
Objectives:- Research examining the relationship between social support and longterm mental illness has, on the whole, failed to address the complexity of the processes involved in receiving support from relationships. As a result, few clinical implications have arisen from the research. The aim of this study was to gain a more detailed understanding about the nature and complexity of the factors that make it difficult for people with long-term mental health problems to form relationships with others and to utilise the social support that is potentially available. The study recruited participants who were suffering from schizophrenia or depression. The comparative element of the design aimed to provide an increased understanding of how the psychiatric disorders impacted on peopleâs perceptions of their relationships, and how their relationships impacted on their emotional difficulties. Design:- The study employed a qualitative research paradigm using a grounded theory methodology. Method:- Two groups of participants were sought. One contained participants suffering from the symptoms of schizophrenia but not depression (the S group). The other contained participants suffering from severe unipolar depression (the D group). Face to face interviews were conducted using semi-structured interview schedules. The interviews aimed to develop a greater insight into usersâ perceptions of their past and current relationships, their beliefs about what friends are for and the way they form friendships, the types of interpersonal problems experienced, perceived contributory factors to these interpersonal difficulties and the nature of the support desired to help overcome them. Results:-Participant responses were analysed using aspects of the grounded theory method. Codes, categories and themes were generated from the data. Some themes were common to both groups. Others reflected important differences between them. Conclusions and Implications:-A tentative theoretical framework was developed to account for the responses given by the two groups to the research questions. The data generated from the responses given by S group participants suggested they had difficulties in reflecting on their own or othersâ mental states (i.e. difficulties in âreflective functioningâ). This had important implications not only for the way the S group described and made sense of their relationships, and could account for some of the different themes generated by the two groups, but also pointed to several new intervention strategies (particularly strategies for overcoming this groupâs social skills deficits). In contrast, the responses given by the D group suggested they had fewer difficulties in âreflective functioningâ. Rather, it appeared that negative internal working models of caring relationships, formed from earlier experiences in their family, had resulted in a deep suspicion of close relationships and a continued anticipation of betrayal and rejection. This theory also accounted for some of the different themes that emerged between the two groups. It also pointed to intervention strategies for the D group. These theories have been incorporated into, and contrasted with, existing theory and research developments. Hypothesised developmental frameworks have been proposed to account for the data. Methodological and conceptual issues in the research have also been addressed and suggestions made for future research
Konsep Ruang dalam dan Ruang Luar Arsitektur Tradisional Suku Atoni di Kampung Tamkesi di Pulau Timor
:This research focuses on the concept of the traditional architectural space. The concept isassured to convey local theories for the contribution of an enduring planning which stays for a longperiod in other words; sustainable. This research will analyze the outcome of a hundredth yearstraditional architecture (settlement) which is said comprises a high architecureâs value even untillnow. The measurement used will be based on the paradigm elaboration of Schulz phenomenologyand Salura Ordering Principles Theory. However the purpose of this research is to create a deepcomprehension (verstehen) about the culture of adaptation in Atony tribe community at TamkesiVillage and to find the concept along with the relation between interior and exterior of theirtraditional settlement architecture. So the result showed that the enviroment relationship, siting,form, figure, and the cycles of nature-culture influenced by the concept of top-down hierarchy andthe presence of a binder (datum) which supported by specific concept: (1) governance-governancetribes of gender, (2) ethnic fraternity, (3) obidience traditions, cultural symbol, spiritual, and (4)the fused-with-nature concept. In short, this concept will makes the custom settlement architectureof Tamkesi Village can continue to survive untill today
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