5,127 research outputs found
Improved timed-mating, non-invasive method using fewer unproven female rats with pregnancy validation via early body mass increases
For studies requiring accurate conception-timing, reliable, efficient methods of detecting oestrus reduce time and costs, whilst improving welfare. Standard methods use vaginal cytology to stage cycle, and breeders are paired–up using approximately five proven females with proven males to achieve at least one conception on a specific day. We describe an alternative, fast, consistent, non-invasive method of timed-mating using detection of lordosis behaviour in Wistar and Lister-Hooded rats that used unproven females with high success rates. Rats under reverse-lighting had body masses recorded pre-mating, day (d) 3-4, d8, d10 and d18 of pregnancy. Using only the presence of the oestrus dance to time-mate females for 24-hrs, 89% Wistar and 88% Lister-Hooded rats successfully conceived. We did not observe behavioural oestrus in Sprague-Dawleys without males present. Significant body mass increases following mating distinguished pregnant from non-pregnant rats, as early as d4 of pregnancy (10% ± 1.0 increase cf 3% ± 1.2). The pattern of increases throughout gestation was similar for all pregnant rats until late pregnancy, when there were smaller increases for primi- and multiparous rats (32% ± 2.5; 25% ± 2.4), whereas nulliparous rats had highest gains (38% ± 1.5). This method demonstrated a distinct refinement of the previous timed-mating common practice used, as disturbance of females was minimised. Only the number required of nulli-, primi- or multiparous rats were mated, and body mass increases validated pregnancy status. This new breeding-management method is now established practice for two strains of rat and resulted in a reduction in animal use
On Feedback Vertex Set: New Measure and New Structures
We present a new parameterized algorithm for the {feedback vertex set}
problem ({\sc fvs}) on undirected graphs. We approach the problem by
considering a variation of it, the {disjoint feedback vertex set} problem ({\sc
disjoint-fvs}), which finds a feedback vertex set of size that has no
overlap with a given feedback vertex set of the graph . We develop an
improved kernelization algorithm for {\sc disjoint-fvs} and show that {\sc
disjoint-fvs} can be solved in polynomial time when all vertices in have degrees upper bounded by three. We then propose a new
branch-and-search process on {\sc disjoint-fvs}, and introduce a new
branch-and-search measure. The process effectively reduces a given graph to a
graph on which {\sc disjoint-fvs} becomes polynomial-time solvable, and the new
measure more accurately evaluates the efficiency of the process. These
algorithmic and combinatorial studies enable us to develop an
-time parameterized algorithm for the general {\sc fvs} problem,
improving all previous algorithms for the problem.Comment: Final version, to appear in Algorithmic
DWSB in heterotic flux compactifications
We address the construction of non-supersymmetric vacua in heterotic
compactifications with intrinsic torsion and background fluxes. In particular,
we implement the approach of domain-wall supersymmetry breaking (DWSB)
previously developed in the context of type II flux compactifications. This
approach is based on considering backgrounds where probe NS5-branes wrapping
internal three-cycles and showing up as four-dimensional domain-walls do not
develop a BPS bound, while all the other BPS bounds characterizing the N=1
supersymmetric compactifications are preserved at tree-level. Via a scalar
potential analysis we provide the conditions for these backgrounds to solve the
ten-dimensional equations of motion including order \alpha' corrections. We
also consider backgrounds where some of the NS5-domain-walls develop a BPS
bound, show their relation to no-scale SUSY-breaking vacua and construct
explicit examples via elliptic fibrations. Finally, we consider backgrounds
with a non-trivial gaugino condensate and discuss their relation to
supersymmetric and non-supersymmetric vacua in the present context.Comment: 56 pages, 1 figur
The Early Bird Catches The Term: Combining Twitter and News Data For Event Detection and Situational Awareness
Twitter updates now represent an enormous stream of information originating
from a wide variety of formal and informal sources, much of which is relevant
to real-world events. In this paper we adapt existing bio-surveillance
algorithms to detect localised spikes in Twitter activity corresponding to real
events with a high level of confidence. We then develop a methodology to
automatically summarise these events, both by providing the tweets which fully
describe the event and by linking to highly relevant news articles. We apply
our methods to outbreaks of illness and events strongly affecting sentiment. In
both case studies we are able to detect events verifiable by third party
sources and produce high quality summaries
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Dose-dependent T-cell Dynamics and Cytokine Cascade Following rVSV-ZEBOV Immunization.
BACKGROUND: The recent West African Ebola epidemic led to accelerated efforts to test Ebola vaccine candidates. As part of the World Health Organisation-led VSV Ebola Consortium (VEBCON), we performed a phase I clinical trial investigating rVSV-ZEBOV (a recombinant vesicular stomatitis virus-vectored Ebola vaccine), which has recently demonstrated protection from Ebola virus disease (EVD) in phase III clinical trials and is currently in advanced stages of licensing. So far, correlates of immune protection are incompletely understood and the role of cell-mediated immune responses has not been comprehensively investigated to date. METHODS: We recruited 30 healthy subjects aged 18-55 into an open-label, dose-escalation phase I trial testing three doses of rVSV-ZEBOV (3×105 plaque-forming units (PFU), 3×106 PFU, 2×107 PFU) (ClinicalTrials.gov; NCT02283099). Main study objectives were safety and immunogenicity, while exploratory objectives included lymphocyte dynamics, cell-mediated immunity and cytokine networks, which were assessed using flow cytometry, ELISpot and LUMINEX assay. FINDINGS: Immunization with rVSV-ZEBOV was well tolerated without serious vaccine-related adverse events. Ebola virus-specific neutralizing antibodies were induced in nearly all individuals. Additionally, vaccinees, particularly within the highest dose cohort, generated Ebola glycoprotein (GP)-specific T cells and initiated a cascade of signaling molecules following stimulation of peripheral blood mononuclear cells with Ebola GP peptides. INTERPRETATION: In addition to a benign safety and robust humoral immunogenicity profile, subjects immunized with 2×107 PFU elicited higher cellular immune responses and stronger interlocked cytokine networks compared to lower dose groups. To our knowledge these data represent the first detailed cell-mediated immuneprofile of a clinical trial testing rVSV-ZEBOV, which is of particular interest in light of its potential upcoming licensure as the first Ebola vaccine. VEBCON trial Hamburg, Germany (NCT02283099)
Impact of inhaled corticosteroids on growth in children with asthma: systematic review and meta-analysis
Background: Long-term inhaled corticosteroids (ICS) may reduce growth velocity and final height of children with asthma. We aimed to evaluate the association between ICS use of >12 months and growth. Methods: We initially searched MEDLINE and EMBASE in July 2013, followed by a PubMed search updated to December 2014. We selected RCTs and controlled observational studies of ICS use in patients with asthma. We conducted random effects meta-analysis of mean differences in growth velocity (cm/year) or final height (cm) between groups. Heterogeneity was assessed using the I2 statistic. Results: We found 23 relevant studies (twenty RCTs and three observational studies) after screening 1882 hits. Meta-analysis of 16 RCTs showed that ICS use significantly reduced growth velocity at one year follow-up (mean difference -0.48 cm/year (95% CI -0.66 to -0.29)). There was evidence of a dose-response effect in three RCTs. Final adult height showed a mean reduction of -1.20 cm (95% CI -1.90 cm to -0.50 cm) with budesonide versus placebo in a high quality RCT. Meta-analysis of two lower quality observational studies revealed uncertainty in the association between ICS use and final adult height, pooled mean difference -0.85 cm (95% CI -3.35 to 1.65). Conclusion: Use of ICS for >12 months in children with asthma has a limited impact on annual growth velocity. In ICS users, there is a slight reduction of about a centimeter in final adult height, which when interpreted in the context of average adult height in England (175 cm for men and 161 cm for women), represents a 0.7% reduction compared to non-ICS users
The formation of professional identity in medical students: considerations for educators
<b>Context</b> Medical education is about more than acquiring an appropriate level of knowledge and developing relevant skills. To practice medicine students need to develop a professional identity – ways of being and relating in professional contexts.<p></p>
<b>Objectives</b> This article conceptualises the processes underlying the formation and maintenance of medical students’ professional identity drawing on concepts from social psychology.<p></p>
<b>Implications</b> A multi-dimensional model of identity and identity formation, along with the concepts of identity capital and multiple identities, are presented. The implications for educators are discussed.<p></p>
<b>Conclusions</b> Identity formation is mainly social and relational in nature. Educators, and the wider medical society, need to utilise and maximise the opportunities that exist in the various relational settings students experience. Education in its broadest sense is about the transformation of the self into new ways of thinking and relating. Helping students form, and successfully integrate their professional selves into their multiple identities, is a fundamental of medical education
Poor youths and ‘pacification’:dilemmas between discourse and practice from the perspective of young people about policing in Rio de Janeiro’s favelas
This article explores the social representations of youngsters from favelas in Rio de Janeiro on
police practices in the context of the implementation of ‘Pacifying Police Units’. Drawing from
fieldwork, participant observation and interviews, the authors analyse the narratives and practices
which influence relations between young people and the police in the Complexo do Alemão
area of the city. The interviewees expressed a demand for further public security and social
services. Young people noted some progress in police practices, although these changes appear
to be unstable. The permanence of violent practices and prejudice by the police was verified in
youngsters’ narratives. Any change in this scenario should be based on the replacement of the
war logic of ‘pacification’ for another logic, that of participation.2030-01-0
The Mitochondrial Ca(2+) Uniporter: Structure, Function, and Pharmacology.
Mitochondrial Ca(2+) uptake is crucial for an array of cellular functions while an imbalance can elicit cell death. In this chapter, we briefly reviewed the various modes of mitochondrial Ca(2+) uptake and our current understanding of mitochondrial Ca(2+) homeostasis in regards to cell physiology and pathophysiology. Further, this chapter focuses on the molecular identities, intracellular regulators as well as the pharmacology of mitochondrial Ca(2+) uniporter complex
Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'.
Innate immune cells must be able to distinguish between direct binding to microbes and detection of components shed from the surface of microbes located at a distance. Dectin-1 (also known as CLEC7A) is a pattern-recognition receptor expressed by myeloid phagocytes (macrophages, dendritic cells and neutrophils) that detects β-glucans in fungal cell walls and triggers direct cellular antimicrobial activity, including phagocytosis and production of reactive oxygen species (ROS). In contrast to inflammatory responses stimulated upon detection of soluble ligands by other pattern-recognition receptors, such as Toll-like receptors (TLRs), these responses are only useful when a cell comes into direct contact with a microbe and must not be spuriously activated by soluble stimuli. In this study we show that, despite its ability to bind both soluble and particulate β-glucan polymers, Dectin-1 signalling is only activated by particulate β-glucans, which cluster the receptor in synapse-like structures from which regulatory tyrosine phosphatases CD45 and CD148 (also known as PTPRC and PTPRJ, respectively) are excluded (Supplementary Fig. 1). The 'phagocytic synapse' now provides a model mechanism by which innate immune receptors can distinguish direct microbial contact from detection of microbes at a distance, thereby initiating direct cellular antimicrobial responses only when they are required
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