187 research outputs found

    Dynamical Boson Stars

    Full text link
    The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called {\em geons}, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name {\em boson stars}. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in Relativity; major revision in 201

    The optimal starting time of postoperative intraperitoneal mitomycin-C therapy with preserved intestinal wound healing

    Get PDF
    BACKGROUND: There is controversy about the effect of the timing of intraperitoneal administration of chemotherapeutic agents on the healing of intestinal anastomosis. We have investigated the effect on intestinal wound healing of mitomycin-C administered at different times post-operatively. METHODS: Eighty-four Wistar-Albino female rats underwent ileal resection and end-to-end anastomosis. The rats were randomly selected for intraperitoneal administration of mitomycin-C or saline as follows: mitomycin-C group (n = 65), 2 mg/kg mitomycin-C; control group (n = 13), 10 ml saline. The former was sub-divided into 5 equal groups (A 1–5) and mitomycin-C was administered postoperatively as follows: day 0 (A1), day 3 (A2), day 5 (A3), day 7 (A4) and day 10 (A5). All the rats were sacrificed on the 14th postoperative day and anastomotic bursting pressures and tissue hydroxyproline levels were determined. RESULTS: Five of the animals died postoperatively: 2 (15.4%) in group A1, 2 (15.4%) in group A2 and 1(7.7%) in group A3. Non-lethal anastomotic leakage was observed in a further five animals: 1 in group A1, 2 in group A2, 1 in group A5 and 1 in the control group. Groups A1 and A2 had significantly lower anastomotic bursting pressures than the other groups (P was <0.05 for each comparison). The anastomotic bursting pressures of group A3, A4 and A5 were comparable with those of the controls (P was >0.05 for each comparison). Tissue hydroxyproline levels in group A1 and A2 were significantly lower than in the controls (P values were <0.05 for each comparison) or the other mitomycin-C sub-groups (P was <0.05 for each comparison). CONCLUSIONS: Intraperitoneal chemotherapy impairs intestinal wound healing when applied before the 5th postoperative day. Additional therapeutic approaches are needed to prevent this potentially lethal side effect of early intraperitoneal mitomycin-C administration

    Both loved and feared: third party punishers are viewed as formidable and likeable, but these reputational benefits may only be open to dominant individuals

    Get PDF
    Journal ArticleResearch Support, Non-U.S. Gov'tCopyright: © 2014 Gordon et al.The datasets associated with this article are available in ORE at http://hdl.handle.net/10871/15639Third party punishment can be evolutionarily stable if there is heterogeneity in the cost of punishment or if punishers receive a reputational benefit from their actions. A dominant position might allow some individuals to punish at a lower cost than others and by doing so access these reputational benefits. Three vignette-based studies measured participants' judgements of a third party punisher in comparison to those exhibiting other aggressive/dominant behaviours (Study 1), when there was variation in the success of punishment (Study 2), and variation in the status of the punisher and the type of punishment used (Study 3). Third party punishers were judged to be more likeable than (but equally dominant as) those who engaged in other types of dominant behaviour (Study 1), were judged to be equally likeable and dominant whether their intervention succeeded or failed (Study 2), and participants believed that only a dominant punisher could intervene successfully (regardless of whether punishment was violent or non-violent) and that subordinate punishers would face a higher risk of retaliation (Study 3). The results suggest that dominance can dramatically reduce the cost of punishment, and that while individuals can gain a great deal of reputational benefit from engaging in third party punishment, these benefits are only open to dominant individuals. Taking the status of punishers into account may therefore help explain the evolution of third party punishment.School of Psychology, University of Exete

    Staying Cool Across the First Year of Middle School

    Get PDF
    As students transition into middle school they must successfully negotiate a new, larger peer context to attain or maintain high social standing. The goal of this study was to examine the extent to which the maintenance, attainment, and loss of a cool status over the course of the sixth grade is associated with student and classroom levels of physical, verbal, and relational aggression. To address this goal, we studied a sample of 1985 (55% girls) ethnically diverse adolescents from 99 sixth grade classrooms in the United States. Attaining a cool status at any point across the school year was associated with stronger aggressive reputations. Additionally, classroom norms for aggressive behavior moderated the association between changes in aggression over the school year and the stability of coolness such that students who maintained their coolness across the school year showed greater increases in their verbally aggressive reputations from fall to spring when they were in classrooms with higher levels of aggression. The findings illustrate the importance of fitting in with social norms for maintaining a high social status among a new set of peers in middle school

    Bullying and Victimization Among Adolescents: The Role of Ethnicity and Ethnic Composition of School Class

    Get PDF
    The present study examined the relationships between ethnicity, peer-reported bullying and victimization, and whether these relationships were moderated by the ethnic composition of the school classes. Participants were 2386 adolescents (mean age: 13 years and 10 months; 51.9% boys) from 117 school classes in the Netherlands. Multilevel analyses showed that, after controlling for the ethnic composition of school class, ethnic minority adolescents were less victimized, but did not differ from the ethnic majority group members on bullying. Victimization was more prevalent in ethnically heterogeneous classes. Furthermore, the results revealed that ethnic minority adolescents bully more in ethnically heterogeneous classes. Our findings suggest that, in order to understand bullying and victimization in schools in ethnically diverse cultures, the ethnic background of adolescents and the ethnic composition of school classes should be taken into account

    Social Intelligence and Academic Achievement as Predictors of Adolescent Popularity

    Get PDF
    This study compared the effects of social intelligence and cognitive intelligence, as measured by academic achievement, on adolescent popularity in two school contexts. A distinction was made between sociometric popularity, a measure of acceptance, and perceived popularity, a measure of social dominance. Participants were 512, 14–15 year-old adolescents (56% girls, 44% boys) in vocational and college preparatory schools in Northwestern Europe. Perceived popularity was significantly related to social intelligence, but not to academic achievement, in both contexts. Sociometric popularity was predicted by an interaction between academic achievement and social intelligence, further qualified by school context. Whereas college bound students gained sociometric popularity by excelling both socially and academically, vocational students benefited from doing well either socially or academically, but not in combination. The implications of these findings were discussed

    Effect of an education programme for patients with osteoarthritis in primary care - a randomized controlled trial

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Osteoarthritis (OA) is a degenerative disease, considered to be one of the major public health problems. Research suggests that patient education is feasible and valuable for achieving improvements in quality of life, in function, well-being and improved coping. Since 1994, Primary Health Care in Malmö has used a patient education programme directed towards OA. The aim of this study was to evaluate the effects of this education programme for patients with OA in primary health care in terms of self-efficacy, function and self-perceived health.</p> <p>Method</p> <p>The study was a single-blind, randomized controlled trial (RCT) in which the EuroQol-5D and Arthritis self-efficacy scale were used to measure self-perceived health and self-efficacy and function was measured with Grip Ability Test for the upper extremity and five different functional tests for the lower extremity.</p> <p>Results</p> <p>We found differences between the intervention group and the control group, comparing the results at baseline and after 6 months in EuroQol-5D (p < 0.001) and in standing one leg eyes closed (p = 0.02) in favour of the intervention group. No other differences between the groups were found.</p> <p>Conclusion</p> <p>This study has shown that patient education for patients with osteoarthritis is feasible in a primary health care setting and can improve self-perceived health as well as function in some degree, but not self-efficacy. Further research to investigate the effect of exercise performance on function, as well as self-efficacy is warranted.</p> <p>Trial registration</p> <p>The trial is registered with ClinicalTrials.gov. Registration number: NCT00979914</p

    Corticofugal Modulation of Initial Neural Processing of Sound Information from the Ipsilateral Ear in the Mouse

    Get PDF
    Background: Cortical neurons implement a high frequency-specific modulation of subcortical nuclei that includes the cochlear nucleus. Anatomical studies show that corticofugal fibers terminating in the auditory thalamus and midbrain are mostly ipsilateral. Differently, corticofugal fibers terminating in the cochlear nucleus are bilateral, which fits to the needs of binaural hearing that improves hearing quality. This leads to our hypothesis that corticofugal modulation of initial neural processing of sound information from the contralateral and ipsilateral ears could be equivalent or coordinated at the first sound processing level. Methodology/Principal Findings: With the focal electrical stimulation of the auditory cortex and single unit recording, this study examined corticofugal modulation of the ipsilateral cochlear nucleus. The same methods and procedures as described in our previous study of corticofugal modulation of contralateral cochlear nucleus were employed simply for comparison. We found that focal electrical stimulation of cortical neurons induced substantial changes in the response magnitude, response latency and receptive field of ipsilateral cochlear nucleus neurons. Cortical stimulation facilitated auditory response and shortened the response latency of physiologically matched neurons whereas it inhibited auditory response and lengthened the response latency of unmatched neurons. Finally, cortical stimulation shifted the best frequencies of cochlear neurons towards those of stimulated cortical neurons

    Genome-Wide Identification of Transcription Start Sites, Promoters and Transcription Factor Binding Sites in E. coli

    Get PDF
    Despite almost 40 years of molecular genetics research in Escherichia coli a major fraction of its Transcription Start Sites (TSSs) are still unknown, limiting therefore our understanding of the regulatory circuits that control gene expression in this model organism. RegulonDB (http://regulondb.ccg.unam.mx/) is aimed at integrating the genetic regulatory network of E. coli K12 as an entirely bioinformatic project up till now. In this work, we extended its aims by generating experimental data at a genome scale on TSSs, promoters and regulatory regions. We implemented a modified 5′ RACE protocol and an unbiased High Throughput Pyrosequencing Strategy (HTPS) that allowed us to map more than 1700 TSSs with high precision. From this collection, about 230 corresponded to previously reported TSSs, which helped us to benchmark both our methodologies and the accuracy of the previous mapping experiments. The other ca 1500 TSSs mapped belong to about 1000 different genes, many of them with no assigned function. We identified promoter sequences and type of σ factors that control the expression of about 80% of these genes. As expected, the housekeeping σ70 was the most common type of promoter, followed by σ38. The majority of the putative TSSs were located between 20 to 40 nucleotides from the translational start site. Putative regulatory binding sites for transcription factors were detected upstream of many TSSs. For a few transcripts, riboswitches and small RNAs were found. Several genes also had additional TSSs within the coding region. Unexpectedly, the HTPS experiments revealed extensive antisense transcription, probably for regulatory functions. The new information in RegulonDB, now with more than 2400 experimentally determined TSSs, strengthens the accuracy of promoter prediction, operon structure, and regulatory networks and provides valuable new information that will facilitate the understanding from a global perspective the complex and intricate regulatory network that operates in E. coli
    corecore