164 research outputs found
The Automorphism Group of Certain Higher Degree Forms
We consider symmetric d-linear forms of dimension n over an algebraically
closed field k of characteristic 0. The "center" of a form is the analogous of
the space of symmetric matrices of a bilinear form. For d>2 the center is a
commutative subalgebra of . The automorphism group of the form
acts naturally on the center. We give a description of this group via this
action.Comment: Title changed. Final version, to appear in appear in Journal of Pure
and Applied Algebr
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The Olfactory Receptor (OR) superfamily, the largest in the vertebrate genome, is responsible for vertebrate olfaction and is traditionally subdivided into 17 OR families. Recent studies characterising whole-OR subgenomes revealed a 'birth and death' model of evolution for a range of species, however little is known about fine-scale evolutionary dynamics within single-OR families. This study reports the first assessment of fine-scale OR evolution and variation in African mole-rats (Bathyergidae), a family of subterranean rodents endemic to sub-Saharan Africa. Because of the selective pressures of life underground, enhanced olfaction is proposed to be fundamental to the evolutionary success of the Bathyergidae, resulting in a highly diversified OR gene-repertoire. Using a PCR-sequencing approach, we analysed variation in the OR7 family across 14 extant bathyergid species, which revealed enhanced levels of functional polymorphisms concentrated across the receptors' ligand-binding region. We propose that mole-rats are able to recognise a broad range of odorants and that this diversity is reflected throughout their OR7 gene repertoire. Using both classic tests and tree-based methods to test for signals of selection, we investigate evolutionary forces across the mole-rat OR7 gene tree. Four well-supported clades emerged in the OR phylogeny, with varying signals of selection; from neutrality to positive and purifying selection. Bathyergid life-history traits and environmental niche-specialisation are explored as possible drivers of adaptive OR evolution, emerging as non-exclusive contributors to the positive selection observed at OR7 genes. Our results reveal unexpected complexity of evolutionary mechanisms acting within a single OR family, providing insightful perspectives into OR evolutionary dynamics
Depression in Zimbabwe: a community approach to prevention and treatment
A position paper on primary health care for the management of mental health in Zimbabwe.This paper reports on a process whereby research findings, generated by a collaborative project between primary health care workers and a University team, were utilized by a community to formulate local plans for the prevention and management of depression. Action-oriented research, with a high level of community participation, follows on directly from the Declaration of Alma-Ata1 and has been called Health Systems Research (HSR). The principle of HSR is that it should be useful and have a direct focus on solving practical and relevant problems.2 Priorities should be generated by health workers and by the community rather than purely by academics and as much as possible of the research should be carried out by those already working at ground level. Results should lead to implementable recommendations and the research is not complete until those recommendations are underway
Attentional bias and treatment adherence in substitute-prescribed opiate users
BACKGROUND: Attentional bias (AB) is implicated in the development and maintenance of substance dependence and in treatment outcome. We assessed the effects of attentional bias modification (ABM), and the relationship between AB and treatment adherence in opiate dependent patients.
METHOD: An independent groups design was used to compare 23 opiate dependent patients with 21 healthy controls. Participants completed an AB task before either a control or an ABM task designed to train attention away from substance-related stimuli. Pre- and post-ABM AB and craving were assessed to determine any changes. Relationships between treatment adherence (‘using on top’ of prescribed opiates or not) and AB, craving and psychopathology were also examined.
RESULTS: There was no baseline difference in AB between patients and controls, and no significant effect of ABM on AB or substance craving. However, treatment adherent patients who did not use illicit opiates on top of their prescribed opiates had statistically significantly greater AB away from substance-related stimuli than both participants using on top and controls, and reported significantly lower levels of craving than non-treatment adherent patients.
CONCLUSION: Whilst we did not find any significant effects of ABM on AB or craving, patients who were treatment adherent differed from both those who were not and from controls in their attentional functioning and substance craving. These findings are the first to suggest that AB may be a within-treatment factor predictive of adherence to pharmacological treatment and potentially of recovery in opiate users
Galaxy Zoo DESI: Detailed Morphology Measurements for 8.7M Galaxies in the DESI Legacy Imaging Surveys
We present detailed morphology measurements for 8.67 million galaxies in the
DESI Legacy Imaging Surveys (DECaLS, MzLS, and BASS, plus DES). These are
automated measurements made by deep learning models trained on Galaxy Zoo
volunteer votes. Our models typically predict the fraction of volunteers
selecting each answer to within 5-10\% for every answer to every GZ question.
The models are trained on newly-collected votes for DESI-LS DR8 images as well
as historical votes from GZ DECaLS. We also release the newly-collected votes.
Extending our morphology measurements outside of the previously-released
DECaLS/SDSS intersection increases our sky coverage by a factor of 4 (5,000 to
19,000 deg) and allows for full overlap with complementary surveys
including ALFALFA and MaNGA.Comment: 20 pages. Accepted at MNRAS. Catalog available via
https://zenodo.org/record/7786416. Pretrained models available via
https://github.com/mwalmsley/zoobot. Vizier and Astro Data Lab access not yet
available. With thanks to the Galaxy Zoo volunteer
The effect of rotavirus vaccine on diarrhoea mortality
Background Approximately 39% of the global diarrhoea deaths in children aged 5 years may be attributable to rotavirus infection. Two rotavirus vaccines were recently introduced to the market, with evidence of efficacy in the USA, Europe and Latin America. We sought to estimate the effectiveness of these vaccines against rotavirus morbidity and mortality
Global Perspectives on Immunization During Pregnancy and Priorities for Future Research and Development: An International Consensus Statement
Immunization during pregnancy has been recommended in an increasing number of countries. The aim of this strategy is to protect pregnant women and infants from severe infectious disease, morbidity and mortality and is currently limited to tetanus, inactivated influenza, and pertussis-containing vaccines. There have been recent advancements in the development of vaccines designed primarily for use in pregnant women (respiratory syncytial virus and group B Streptococcus vaccines). Although there is increasing evidence to support vaccination in pregnancy, important gaps in knowledge still exist and need to be addressed by future studies. This collaborative consensus paper provides a review of the current literature on immunization during pregnancy and highlights the gaps in knowledge and a consensus of priorities for future research initiatives, in order to optimize protection for both the mother and the infant
Vaccine-induced mucosal immunity to poliovirus: analysis of cohorts from an open-label, randomised controlled trial in Latin American infants.
BACKGROUND: Identification of mechanisms that limit poliovirus replication is crucial for informing decisions aimed at global polio eradication. Studies of mucosal immunity induced by oral poliovirus (OPV) or inactivated poliovirus (IPV) vaccines and mixed schedules thereof will determine the effectiveness of different vaccine strategies to block virus shedding. We used samples from a clinical trial of different vaccination schedules to measure intestinal immunity as judged by neutralisation of virus and virus-specific IgA in stools. METHODS: In the FIDEC trial, Latin American infants were randomly assigned to nine groups to assess the efficacy of two schedules of bivalent OPV (bOPV) and IPV and challenge with monovalent type 2 OPV, and stools samples were collected. We selected three groups of particular interest-the bOPV control group (serotypes 1 and 3 at 6, 10, and 14 weeks), the trivalent attenuated OPV (tOPV) control group (tOPV at 6, 10, and 14 weeks), and the bOPV-IPV group (bOPV at 6, 10, and 14 weeks plus IPV at 14 weeks). Neutralising activity and poliovirus type-specific IgA were measured in stool after a monovalent OPV type 2 challenge at 18 weeks of age. Mucosal immunity was measured by in-vitro neutralisation of a type 2 polio pseudovirus (PV2). Neutralisation titres and total and poliovirus-type-specific IgG and IgA concentrations in stools were assessed in samples collected before challenge and 2 weeks after challenge from all participants. FINDINGS: 210 infants from Guatemala and Dominican Republic were included in this analysis. Of 38 infants tested for mucosal antibody in the tOPV group, two were shedding virus 1 week after challenge, compared with 59 of 85 infants receiving bOPV (p<0·0001) and 53 of 87 infants receiving bOPV-IPV (p<0·0001). Mucosal type 2 neutralisation and type-specific IgA were noted primarily in response to tOPV. An inverse correlation was noted between virus shedding and both serum type 2 neutralisation at challenge (p<0·0001) and mucosal type 2 neutralisation at challenge (p<0·0001). INTERPRETATION: Mucosal type-2-specific antibodies can be measured in stool and develop in response to receipt of OPV type 2 either in the primary vaccine series or at challenge. These mucosal antibodies influence the amount of virus that is shed in an established infection. FUNDING: Bill & Melinda Gates Foundation
Pertussis Prevention: Reasons for Resurgence, and Differences in the Current Acellular Pertussis Vaccines
Pertussis is an acute respiratory disease caused by Bordetella pertussis. Due to its frequency and severity, prevention of pertussis has been considered an important public health issue for many years. The development of the whole-cell pertussis vaccine (wPV) and its introduction into the pediatric immunization schedule was associated with a marked reduction in pertussis cases in the vaccinated cohort. However, due to the frequency of local and systemic adverse events after immunization with wPV, work on a less reactive vaccine was undertaken based on isolated B. pertussis components that induced protective immune responses with fewer local and systemic reactions. These component vaccines were termed acellular vaccines and contained one or more pertussis antigens, including pertussis toxin (PT), filamentous haemagglutinin (FHA), pertactin (PRN), and fimbrial proteins 2 (FIM2) and 3 (FIM3). Preparations containing up to five components were developed, and several efficacy trials clearly demonstrated that the aPVs were able to confer comparable short-term protection than the most effective wPVs with fewer local and systemic reactions. There has been a resurgence of pertussis observed in recent years. This paper reports the results of a Consensus Conference organized by the World Association for Infectious Disease and Immunological Disorders (WAidid) on June 22, 2018, in Perugia, Italy, with the goal of evaluating the most important reasons for the pertussis resurgence and the role of different aPVs in this resurgence
Temporomandibular joint dysfunction and orthognathic surgery: a retrospective study
<p>Abstract</p> <p>Background</p> <p>Relations between maxillo-mandibular deformities and TMJ disorders have been the object of different studies in medical literature and there are various opinions concerning the alteration of TMJ dysfunction after orthognathic surgery. The purpose of the present study was to evaluate TMJ disorders changes before and after orthognathic surgery, and to assess the risk of creating new TMJ symptoms on asymptomatic patients.</p> <p>Methods</p> <p>A questionnaire was sent to 176 patients operated at the Maxillo-Facial Service of the Lille's 2 Universitary Hospital Center (Chairman Pr Joël Ferri) from 01.01.2006 to 01.01.2008. 57 patients (35 females and 22 males), age range from 16 to 65 years old, filled the questionnaire. The prevalence and the results on pain, sounds, clicking, joint locking, limited mouth opening, and tenseness were evaluated comparing different subgroups of patients.</p> <p>Results</p> <p>TMJ symptoms were significantly reduced after treatment for patients with pre-operative symptoms. The overall subjective treatment outcome was: improvement for 80.0% of patients, no change for 16.4% of patients, and an increase of symptoms for 3.6% of them. Thus, most patients were very satisfied with the results. However the appearance of new onset of TMJ symptoms is common. There was no statistical difference in the prevalence of preoperative TMJ symptoms and on postoperative results in class II compared to class III patients.</p> <p>Conclusions</p> <p>These observations demonstrate that: there is a high prevalence of TMJ disorders in dysgnathic patients; most of patients with preoperative TMJ signs and symptoms can improve TMJ dysfunction and pain levels can be reduced by orthognathic treatment; a percentage of dysgnathic patients who were preoperatively asymptomatic can develop TMJ disorders after surgery but this risk is low.</p
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