197 research outputs found
Fermionic Zero Modes of Supergravity Cosmic Strings
Recent developments in string theory suggest that cosmic strings could be
formed at the end of brane inflation. Supergravity provides a realistic model
to study the properties of strings arising in brane inflation. Whilst the
properties of cosmic strings in flat space-time have been extensively studied
there are significant complications in the presence of gravity. We study the
effects of gravitation on cosmic strings arising in supergravity. Fermion zero
modes are a common feature of cosmic strings, and generically occur in
supersymmetric models. The corresponding massless currents can give rise to
stable string loops (vortons). The vorton density in our universe is strongly
constrained, allowing many theories with cosmic strings to be ruled out. We
investigate the existence of fermion zero modes on cosmic strings in
supergravity theories. A general index theorem for the number of zero modes is
derived. We show that by including the gravitino, some (but not all) zero modes
disappear. This weakens the constraints on cosmic string models. In particular,
winding number one cosmic D-strings in models of brane inflation are not
subject to vorton constraints. We also discuss the effects of supersymmetry
breaking on cosmic D-strings.Comment: 33 page
Chronic Rhinosinusitis: Potential Role of Microbial Dysbiosis and Recommendations for Sampling Sites.
Chronic rhinosinusitis (CRS) is an inflammatory condition that affects up to 12% of the human population in developed countries. Previous studies examining the potential role of the sinus bacterial microbiota within CRS infections have found inconsistent results, possibly because of inconsistencies in sampling strategies. The aim of this study was to determine whether the sinus microbiome is altered in CRS and additionally if the middle meatus is a suitable representative site for sampling the sinus microbiome. Swab samples were collected from 12 healthy controls and 21 CRS patients, including all eight sinuses for CRS patients and between one and five sinuses for control subjects. The left and right middle meatus and nostril swabs were also collected. Significant differences in the sinus microbiomes between CRS and control samples were revealed using high-throughput 16S rRNA gene sequencing. The genus Escherichia was over-represented in CRS sinuses, and associations between control patients and Corynebacterium and Dolosigranulum were also identified. Comparisons of the middle meatuses between groups did not reflect these differences, and the abundance of the genus Escherichia was significantly lower at this location. Additionally, intra-patient variation was lower between sinuses than between sinus and middle meatus, which together with the above results suggests that the middle meatus is not an effective representative sampling site
Reducing drug related deaths : a pre-implementation assessment of knowledge,barriers and enablers for naloxone distribution through general practice
Peer reviewedPublisher PD
Stat5 Synergizes with T Cell Receptor/Antigen Stimulation in the Development of Lymphoblastic Lymphoma
Signal transducer and activator of transcription (STAT) proteins are latent transcription factors that mediate a wide range of actions induced by cytokines, interferons, and growth factors. We now report the development of thymic T cell lymphoblastic lymphomas in transgenic mice in which Stat5a or Stat5b is overexpressed within the lymphoid compartment. The rate of lymphoma induction was markedly enhanced by immunization or by the introduction of TCR transgenes. Remarkably, the Stat5 transgene potently induced development of CD8+ T cells, even in mice expressing a class II–restricted TCR transgene, with resulting CD8+ T cell lymphomas. These data demonstrate the oncogenic potential of dysregulated expression of a STAT protein that is not constitutively activated, and that TCR stimulation can contribute to this process
Epidemiological Pathology of Dementia: Attributable-Risks at Death in the Medical Research Council Cognitive Function and Ageing Study
Researchers from the Medical Research Council Cognitive Function and Ageing Neuropathology Study carry out an analysis of brain pathologies contributing to dementia, within a cohort of elderly individuals in the UK who agreed to brain donation
Signatures of Short Distance Physics in the Cosmic Microwave Background
We systematically investigate the effect of short distance physics on the
spectrum of temperature anistropies in the Cosmic Microwave Background produced
during inflation. We present a general argument-assuming only low energy
locality-that the size of such effects are of order H^2/M^2, where H is the
Hubble parameter during inflation, and M is the scale of the high energy
physics.
We evaluate the strength of such effects in a number of specific string and M
theory models. In weakly coupled field theory and string theory models, the
effects are far too small to be observed. In phenomenologically attractive
Horava-Witten compactifications, the effects are much larger but still
unobservable. In certain M theory models, for which the fundamental Planck
scale is several orders of magnitude below the conventional scale of grand
unification, the effects may be on the threshold of detectability.
However, observations of both the scalar and tensor fluctuation contributions
to the Cosmic Microwave Background power spectrum-with a precision near the
cosmic variance limit-are necessary in order to unambiguously demonstrate the
existence of these signatures of high energy physics. This is a formidable
experimental challenge.Comment: 49 pages, 2 figures. References added, minor typos correcte
A qualitative study of nursing student experiences of clinical practice
BACKGROUND: Nursing student's experiences of their clinical practice provide greater insight to develop an effective clinical teaching strategy in nursing education. The main objective of this study was to investigate student nurses' experience about their clinical practice. METHODS: Focus groups were used to obtain students' opinion and experiences about their clinical practice. 90 baccalaureate nursing students at Shiraz University of Medical Sciences (Faculty of Nursing and Midwifery) were selected randomly from two hundred students and were arranged in 9 groups of ten students. To analyze the data the method used to code and categories focus group data were adapted from approaches to qualitative data analysis. RESULTS: Four themes emerged from the focus group data. From the students' point of view," initial clinical anxiety", "theory-practice gap"," clinical supervision", professional role", were considered as important factors in clinical experience. CONCLUSION: The result of this study showed that nursing students were not satisfied with the clinical component of their education. They experienced anxiety as a result of feeling incompetent and lack of professional nursing skills and knowledge to take care of various patients in the clinical setting
Climate Change Meets the Law of the Horse
The climate change policy debate has only recently turned its full attention to adaptation - how to address the impacts of climate change we have already begun to experience and that will likely increase over time. Legal scholars have in turn begun to explore how the many different fields of law will and should respond. During this nascent period, one overarching question has gone unexamined: how will the legal system as a whole organize around climate change adaptation? Will a new distinct field of climate change adaptation law and policy emerge, or will legal institutions simply work away at the problem through unrelated, duly self-contained fields, as in the famous Law of the Horse? This Article is the first to examine that question comprehensively, to move beyond thinking about the law and climate change adaptation to consider the law of climate change adaptation. Part I of the Article lays out our methodological premises and approach. Using a model we call Stationarity Assessment, Part I explores how legal fields are structured and sustained based on assumptions about the variability of natural, social, and economic conditions, and how disruptions to that regime of variability can lead to the emergence of new fields of law and policy. Case studies of environmental law and environmental justice demonstrate the model’s predictive power for the formation of new distinct legal regimes. Part II applies the Stationarity Assessment model to the topic of climate change adaptation, using a case study of a hypothetical coastal region and the potential for climate change impacts to disrupt relevant legal doctrines and institutions. We find that most fields of law appear capable of adapting effectively to climate change. In other words, without some active intervention, we expect the law and policy of climate change adaptation to follow the path of the Law of the Horse - a collection of fields independently adapting to climate change - rather than organically coalescing into a new distinct field. Part III explores why, notwithstanding this conclusion, it may still be desirable to seek a different trajectory. Focusing on the likelihood of systemic adaptation decisions with perverse, harmful results, we identify the potential benefits offered by intervening to shape a new and distinct field of climate change adaptation law and policy. Part IV then identifies the contours of such a field, exploring the distinct purposes of reducing vulnerability, ensuring resiliency, and safeguarding equity. These features provide the normative policy components for a law of climate change adaptation that would be more than just a Law of the Horse. This new field would not replace or supplant any existing field, however, as environmental law did with regard to nuisance law, and it would not be dominated by substantive doctrine. Rather, like the field of environmental justice, this new legal regime would serve as a holistic overlay across other fields to ensure more efficient, effective, and just climate change adaptation solutions
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