1,753 research outputs found
The spin parameter of uniformly rotating compact stars
We study the dimensionless spin parameter of uniformly
rotating neutron stars and quark stars in general relativity. We show
numerically that the maximum value of the spin parameter of a neutron star
rotating at the Keplerian frequency is for a wide class
of realistic equations of state. This upper bound is insensitive to the mass of
the neutron star if the mass of the star is larger than about . On
the other hand, the spin parameter of a quark star modeled by the MIT bag model
can be larger than unity and does not have a universal upper bound. Its value
also depends strongly on the bag constant and the mass of the star.
Astrophysical implications of our finding will be discussed.Comment: Minor changes to match the published versio
13,915 reasons for equity in sexual offences legislation: A national school-based survey in South Africa
<p>Abstract</p> <p>Objective</p> <p>Prior to 2007, forced sex with male children in South Africa did not count as rape but as "indecent assault", a much less serious offence. This study sought to document prevalence of male sexual violence among school-going youth.</p> <p>Design</p> <p>A facilitated self-administered questionnaire in nine of the 11 official languages in a stratified (province/metro/urban/rural) last stage random national sample.</p> <p>Setting</p> <p>Teams visited 5162 classes in 1191 schools, in October and November 2002.</p> <p>Participants</p> <p>A total of 269,705 learners aged 10–19 years in grades 6–11. Of these, 126,696 were male.</p> <p>Main outcome measures</p> <p>Schoolchildren answered questions about exposure in the last year to insults, beating, unwanted touching and forced sex. They indicated the sex of the perpetrator, and whether this was a family member, a fellow schoolchild, a teacher or another adult. Respondents also gave the age when they first suffered forced sex and when they first had consensual sex.</p> <p>Results</p> <p>Some 9% (weighted value based on 13915/127097) of male respondents aged 11–19 years reported forced sex in the last year. Of those aged 18 years at the time of the survey, 44% (weighted value of 5385/11450) said they had been forced to have sex in their lives and 50% reported consensual sex. Perpetrators were most frequently an adult not from their own family, followed closely in frequency by other schoolchildren. Some 32% said the perpetrator was male, 41% said she was female and 27% said they had been forced to have sex by both male and female perpetrators. Male abuse of schoolboys was more common in rural areas while female perpetration was more an urban phenomenon.</p> <p>Conclusion</p> <p>This study uncovers endemic sexual abuse of male children that was suspected but hitherto only poorly documented. Legal recognition of the criminality of rape of male children is a first step. The next steps include serious investment in supporting male victims of abuse, and in prevention of all childhood sexual abuse.</p
Impact of community-based interventions on condom use in the Tłįchǫ region of Northwest Territories, Canada
<p>Abstract</p> <p>Background</p> <p>Since 2005, the Tłįchǫ Community Services Agency (TCSA) in Canada's Northwest Territories (NT) has addressed rising rates of sexually transmitted infections (STI). In 2009, STI rates in the NT were ten times higher than the national rate and Tłįchǫ regional rates were nearly four times that of the NT – 91 cases per 1000 people. We describe a social audit process that assessed the impact of an evidence-based community-led intervention.</p> <p>Methods</p> <p>A baseline survey of sexual health knowledge, attitudes and behaviours in 2006/07 provided evidence for a Community Action Research Team (CART) to develop and to put in place culturally appropriate interventions in the Tłįchǫ region. A follow-up study in 2010 sought to assess the impact of CART activities on condom use and underlying conscious knowledge, attitudes, subjective norms, intention to change, sense of agency and discussions related to condom use and STI risks. We report the contrasts using Odds Ratios (OR) and 95% confidence intervals (CI).</p> <p>Results</p> <p>One in every three follow-up respondents (315/808) participated in at least one CART activity. Participation in highly ranked interventions was associated with increased condom use during the last sexual encounter (OR 1.45, 95%CI 1.07-1.98). Those exposed to three or more activities were more likely to talk openly about condoms (OR 2.08, 95%CI 1.41-3.28), but were also less likely to be monogamous (OR 0.49, 95%CI 0.29-0.90).</p> <p>Conclusions</p> <p>The measurable impact on condom use indicates a strong beginning for the Tłįchǫ community intervention programmes. The interventions also seem to generate increased discussion, often a precursor to action. The Tłįchǫ can use the evidence to improve and refocus their programming, increase knowledge and continue to improve safe condom use practices.</p
Norwegian patients on generic antihypertensive drugs: a qualitative study of their own experiences
Multimodal behavioral treatment of migraine: An Internet-administered, randomized, controlled trial
Introduction. Multimodal approaches in behavioral treatment have gained recent interest, with proven efficacy for migraine. The utility of the Internet has been demonstrated for behavioral treatment of headache disorders, but not specifically for migraine. The aim of the study was to develop and evaluate an Internet-based multimodal behavior treatment (MBT) program for migraine and to test hand massage treatment as an adjunct. Methods. Eighty-three adults, 58 women and 25 men, with at least two migraine attacks a month were recruited via advertisements. An MBT program aiming at improvements in life-style and stress coping was developed for this study and, together with a diary, adapted for use over the Internet. Participants were randomized to MBT with and without hand massage and to a control group, and were followed for 11 months. Questionnaires addressing issues of quality of life (PQ23) and depressive symptoms (MADRS-S) were used. Results. A 50%, or greater, reduction in migraine frequency was found in 40% and 42% of participants of the two groups receiving MBT (with and without hand massage, respectively), who statistically were significantly more improved than participants in the control group. No effect of hand massage was detected, and gender did not show any independent contribution to the effect in a multivariate analysis. Conclusions. MBT administered over the Internet appears feasible and effective in the treatment of migraine, but no effect of hand massage was found. For increased knowledge on long-term effects and the modes of action of the present MBT program, further studies are needed
The GATA1s isoform is normally down-regulated during terminal haematopoietic differentiation and over-expression leads to failure to repress MYB, CCND2 and SKI during erythroid differentiation of K562 cells
Background: Although GATA1 is one of the most extensively studied haematopoietic transcription factors little is currently known about the physiological functions of its naturally occurring isoforms GATA1s and GATA1FL in humans—particularly whether the isoforms have distinct roles in different lineages and whether they have non-redundant roles in haematopoietic differentiation. As well as being of general interest to understanding of haematopoiesis, GATA1 isoform biology is important for children with Down syndrome associated acute megakaryoblastic leukaemia (DS-AMKL) where GATA1FL mutations are an essential driver for disease pathogenesis.
<p/>Methods: Human primary cells and cell lines were analyzed using GATA1 isoform specific PCR. K562 cells expressing GATA1s or GATA1FL transgenes were used to model the effects of the two isoforms on in vitro haematopoietic differentiation.
<p/>Results: We found no evidence for lineage specific use of GATA1 isoforms; however GATA1s transcripts, but not GATA1FL transcripts, are down-regulated during in vitro induction of terminal megakaryocytic and erythroid differentiation in the cell line K562. In addition, transgenic K562-GATA1s and K562-GATA1FL cells have distinct gene expression profiles both in steady state and during terminal erythroid differentiation, with GATA1s expression characterised by lack of repression of MYB, CCND2 and SKI.
<p/>Conclusions: These findings support the theory that the GATA1s isoform plays a role in the maintenance of proliferative multipotent megakaryocyte-erythroid precursor cells and must be down-regulated prior to terminal differentiation. In addition our data suggest that SKI may be a potential therapeutic target for the treatment of children with DS-AMKL
Interleaved Parton Showers and Tuning Prospects
General-purpose Monte Carlo event generators have become important tools in
particle physics, allowing the simulation of exclusive hadronic final states.
In this article we examine the Pythia 8 generator, in particular focusing on
its parton-shower algorithms. Some relevant new additions to the code are
introduced, that should allow for a better description of data. We also
implement and compare with 2 to 3 real-emission QCD matrix elements, to check
how well the shower algorithm fills the phase space away from the soft and
collinear regions. A tuning of the generator to Tevatron data is performed for
two PDF sets and the impact of first new LHC data is examined
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Attention-based bi-directional long-short term memory network for earthquake prediction
An earthquake is a tremor felt on the surface of the earth created by the movement of the major pieces of its outer shell. Till now, many attempts have been made to forecast earthquakes, which saw some success, but these attempted models are specific to a region. In this paper, an earthquake occurrence and location prediction model is proposed. After reviewing the literature, long short-term memory (LSTM) is found to be a good option for building the model because of its memory-keeping ability. Using the Keras tuner, the best model was selected from candidate models, which are composed of combinations of various LSTM architectures and dense layers. This selected model used seismic indicators from the earthquake catalog of Bangladesh as features to predict earthquakes of the following month. and Attention mechanism was added to the LSTM architecture to improve the model’s earthquake occurrence prediction accuracy, which was 74.67%. Additionally, a regression model was built using LSTM and dense layers to predict the earthquake epicenter as a distance from a predefined location, which provided a root mean square error of 1.25
Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.
Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses
Peroxisome Proliferator-Activated Receptor alpha (PPAR alpha) down-regulation in cystic fibrosis lymphocytes
Background: PPARs exhibit anti-inflammatory capacities and are potential modulators of the inflammatory response. We hypothesized that their expression and/or function may be altered in cystic fibrosis (CF), a disorder characterized by an excessive host inflammatory response.
Methods: PPARα, β and γ mRNA levels were measured in peripheral blood cells of CF patients and healthy subjects via RT-PCR. PPARα protein expression and subcellular localization was determined via western blot and immunofluorescence, respectively. The activity of PPARα was analyzed by gel shift assay.
Results: In lymphocytes, the expression of PPARα mRNA, but not of PPARβ, was reduced (-37%; p < 0.002) in CF patients compared with healthy persons and was therefore further analyzed. A similar reduction of PPARα was observed at protein level (-26%; p < 0.05). The transcription factor was mainly expressed in the cytosol of lymphocytes, with low expression in the nucleus. Moreover, DNA binding activity of the transcription factor was 36% less in lymphocytes of patients (p < 0.01). For PPARα and PPARβ mRNA expression in monocytes and neutrophils, no significant differences were observed between CF patients and healthy persons. In all cells, PPARγ mRNA levels were below the detection limit.
Conclusion: Lymphocytes are important regulators of the inflammatory response by releasing cytokines and antibodies. The diminished lymphocytic expression and activity of PPARα may therefore contribute to the inflammatory processes that are observed in CF
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