Unimodality of steady state distributions of growing cell populations

We consider an equation for the evolution of growing and dividing cells, and show, using a result of Kato and McLeod, that the probability density function for the stationary size distribution is necessarily unimodal

A protocol for investigation of the effects of outdoor air pollution on stroke incidence, phenotypes and survival using the South London Stroke Register.

Stroke is a major cause of death and disability. About 5.3 million people die every year from stroke worldwide with over 9 million people surviving at any one time after suffering a stroke. About 1 in 4 men and 1 in 5 women aged 45 years will suffer a stroke if they live to their 85th year. It is estimated that by 2023 there will be an absolute increase in the number of people experiencing a first ever stroke of about 30% compared with 1983. In the UK, stroke is the third commonest cause of death and the most common cause of adult physical disability and consumes 5% of the health and social services budget. Stroke is assuming strategic public health importance because of increased awareness in society, an ageing population and emerging new treatments. It is an NHS health service and research priority, being identified as a target in Our Healthier Nation and the NSF for Older People for prevention and risk factor control and in the NHS Plan as a disease requiring intermediate care planning and reduction in inequalities of care. Whilst a number of risk factors for stroke are well known (e.g. increasing age, ethnicity, socioeconomic deprivation, hypertension), the potential importance of outdoor air pollution as a modifiable risk factor is much less well recognised. This is because studies to date are inconclusive or have methodological limitations. In Sheffield, we estimated that 11% of stroke deaths may be linked to current levels of outdoor air pollution and this high figure is explained by the fact that so many people are exposed to air pollution.We plan to study the effects of outdoor air pollution on stroke using a series of epidemiological (i.e. population based) studies. The purpose of this project is: to examine if short term increases in pollution can trigger a stroke in susceptible individuals, to investigate if the occurrence of stroke is higher amongst people living in more polluted areas (which would be explained by a combination of exposure to short term increases and longer term exposure to higher pollution levels), and to see if people living in more polluted areas have reduced survival following their stroke. We will use geographical information systems, robust statistical methods and powerful grid computing facilities to link and analyse the data. The datasets we will use are the South London Stroke Register database, daily monitored pollution data from national monitoring networks and modelled pollution data for London from the Greater London Authority. The South London Stroke Register records information on all patients who suffer a stroke ("incident" cases) living within a defined area. This stroke incidence dataset offers major advantages over previous studies examining the effects of pollution on hospital admissions and mortality, as not all patients with stroke are admitted or die and there may be a delay between the onset of stroke and admission or death. In addition, it contains other useful information, particularly the type of stroke people have suffered. Air pollution is a potentially modifiable risk factor for stroke. This study will provide robust population level evidence regarding the effects of outdoor air pollution on stroke. If it confirms the link, it will suggest to policy-makers at national and international levels that targeting policy interventions at high pollution areas may be a feasible option for stroke prevention

Development of an international standard set of outcome measures for patients with atrial fibrillation: a report of the International Consortium for Health Outcomes Measurement (ICHOM) atrial fibrillation working group.

AIMS: As health systems around the world increasingly look to measure and improve the value of care that they provide to patients, being able to measure the outcomes that matter most to patients is vital. To support the shift towards value-based health care in atrial fibrillation (AF), the International Consortium for Health Outcomes Measurement (ICHOM) assembled an international Working Group (WG) of 30 volunteers, including health professionals and patient representatives to develop a standardized minimum set of outcomes for benchmarking care delivery in clinical settings. METHODS AND RESULTS: Using an online-modified Delphi process, outcomes important to patients and health professionals were selected and categorized into (i) long-term consequences of disease outcomes, (ii) complications of treatment outcomes, and (iii) patient-reported outcomes. The WG identified demographic and clinical variables for use as case-mix risk adjusters. These included baseline demographics, comorbidities, cognitive function, date of diagnosis, disease duration, medications prescribed and AF procedures, as well as smoking, body mass index (BMI), alcohol intake, and physical activity. Where appropriate, and for ease of implementation, standardization of outcomes and case-mix variables was achieved using ICD codes. The standard set underwent an open review process in which over 80% of patients surveyed agreed with the outcomes captured by the standard set. CONCLUSION: Implementation of these consensus recommendations could help institutions to monitor, compare and improve the quality and delivery of chronic AF care. Their consistent definition and collection, using ICD codes where applicable, could also broaden the implementation of more patient-centric clinical outcomes research in AF

The Outer Envelopes of Globular Clusters. I. NGC 7089 (M2)

We present the results of a wide-field imaging survey of the periphery of the Milky Way globular cluster NGC 7089 (M2). Data were obtained with MegaCam on the Magellan Clay Telescope, and the Dark Energy Camera on the Blanco Telescope. We find that M2 is embedded in a diffuse stellar envelope extending to a radial distance of at least $\sim 60^{\prime}$ ($\sim 210$ pc) -- five times the nominal tidal radius of the cluster. The envelope appears nearly circular in shape, has a radial density decline well described by a power law of index $\gamma = -2.2 \pm 0.2$, and contains approximately $1.6\%$ of the luminosity of the entire system. While the origin of the envelope cannot be robustly identified using the presently available data, the fact that M2 also hosts stellar populations exhibiting a broad dispersion in the abundances of both iron and a variety of neutron capture elements suggests that this object might plausibly constitute the stripped nucleus of a dwarf Galaxy that was long ago accreted and destroyed by the Milky Way.Comment: 15 pages, 12 figures, accepted for publishing in MNRA

A population of large neurons in laminae III and IV of the rat spinal cord that have long dorsal dendrites and lack the neurokinin 1 receptor

The dorsal horn of the rat spinal cord contains a population of large neurons with cell bodies in laminae III or IV, that express the neurokinin 1 receptor (NK1r) and have long dorsal dendrites that branch extensively within the superficial laminae. In this study, we have identified a separate population of neurons that have similar dendritic morphology, but lack the NK1r. These cells also differ from the NK1r-expressing neurons in that they have significantly fewer contacts from substance P-containing axons and are not retrogradely labelled following injection of tracer into the caudal ventrolateral medulla. We also provide evidence that these cells do not belong to the postsynaptic dorsal column pathway or the spinothalamic tract. It is therefore likely that these cells do not have supraspinal projections. They may provide a route through which information transmitted by C fibres that lack neuropeptides is conveyed to deeper laminae. The present findings demonstrate the need for caution when attempting to classify neurons solely on the basis of somatodendritic morphology

Factors associated with smoking in pregnancy

The aim of this cross-sectional study was to identify factors related to smoking during pregnancy. The sample included 267 puerperae hospitalized in the maternity unit of a university hospital in Porto Alegre/RS. The data were collected through a self-applied instrument and statistically analyzed. The majority of the puerperae (51.3%) were between 18 and 25 years old, 55.4% were nonsmokers, 25.5% were smokers, 19.1% had recently ceased smoking (in abstinence). The nonsmokers had more consultations than the smokers and the abstinent smokers (p=0.025). The number of women who had more than one child was higher among smokers than among nonsmokers and abstinent smokers (p=0.002). Women were more likely to stop smoking before pregnancy when they had a partner who was a nonsmoker (p=0.007). Several factors influence smoking and smoking cessation and these are important in prenatal interventions aimed at pregnant women and their partners

Bioassay studies support the potential for latrogenic transmission of variant Creutzfeldt Jakob disease through dental procedures

Background: Evidence is required to quantify the potential risks of transmission of variant Creutzfeldt Jakob (vCJD) through dental procedures. Studies, using animal models relevant to vCJD, were performed to address two questions. Firstly, whether oral tissues could become infectious following dietary exposure to BSE? Secondly, would a vCJD-contaminated dental instrument be able to transmit disease to another patient? Methods: BSE-301V was used as a clinically relevant model for vCJD. VM-mice were challenged by injection of infected brain homogenate into the small intestine (Q1) or by five minute contact between a deliberately-contaminated dental file and the gingival margin (Q2). Ten tissues were collected from groups of challenged mice at three or four weekly intervals, respectively. Each tissue was pooled, homogenised and bioassayed in indicator mice. Findings: Challenge via the small intestine gave a transmission rate of 100% (mean incubation 157±17 days). Infectivity was found in both dental pulp and the gingival margin within 3 weeks of challenge and was observed in all tissues tested within the oral cavity before the appearance of clinical symptoms. Following exposure to deliberately contaminated dental files, 97% of mice developed clinical disease (mean incubation 234±33 days). Interpretation: Infectivity was higher than expected, in a wider range of oral tissues, than was allowed for in previous risk assessments. Disease was transmitted following transient exposure of the gingiva to a contaminated dental file. These observations provide evidence that dental procedures could be a route of cross-infection for vCJD and support the enforcement of single-use for certain dental instruments

A numerical modelling and simulation of core-scale sandstone acidizing process: a study on the effect of temperature

A wide and comprehensive understanding of the chemical reactions and mechanisms of HBF4 is crucial as it significantly influences its performance in stimulating a sandstone formation. In general, it is well-known that HBF4 is able to provide a deeper penetration into the sandstone matrix before being spent due to its uniquely slow hydrolysis ability to produce HF. In the present study, a 3D numerical modelling and simulation were conducted to examine the capability of HBF4 in enhancing the porosity and permeability of the sandstone matrix. The model is built in COMSOL® Multiphysics commercial software of computational fluid dynamics (CFD) to simulate the acid core flooding process on sandstone core. The model had been validated against the experimental data in the literature. The results matched with the measured plot data very well. The effect of temperature on the performance HBF4 sandstone acidizing is evaluated in this study. The simulation results indicated that at low temperature of 25 °C, HBF4 is not very effective, as justified in its poor porosity and permeability increments of only 1.07 and 1.23, respectively. However, at elevated temperatures, the porosity and permeability enhancement also become increasingly more significant, which showed 1.26 and 2.06, respectively, at 65 °C; and 1.67 and 7.06, respectively, at 105 °C. Therefore, one can conclude that HBF4 acid treatment performed better at elevated temperatures due to increased hydrolysis rate, which is a governing function in HBF4 sandstone acidizing. Overall, this model had provided a reliable alternative to optimize various other parameters of HBF4 acid treatment

Lambda and Antilambda polarization from deep inelastic muon scattering

We report results of the first measurements of Lambda and Antilambda polarization produced in deep inelastic polarized muon scattering on the nucleon. The results are consistent with an expected trend towards positive polarization with increasing x_F. The polarizations of Lambda and Antilambda appear to have opposite signs. A large negative polarization for Lambda at low positive x_F is observed and is not explained by existing models.A possible interpretation is presented.Comment: 9 pages, 2 figure

Concussion knowledge and experience among Welsh amateur rugby union coaches and referees

Background Rugby union is a collision sport where participants are at high risk of sustaining a concussion. In settings where there is little qualified medical supervision, certain stakeholders (eg, coaches and officials) should possess sufficient knowledge in regard to the recognition and management of concussion. Aim The aim of this study was to assess the knowledge and experience of various aspects of concussion among coaches and referees involved in Welsh amateur rugby union. Methods A questionnaire was distributed to 1843 coaches and 420 referees. Results A total of 333 coaches and 283 referees completed the questionnaire (18% and 68% response rates, respectively). Participants exhibited greater knowledge of concussion symptom recognition relative to knowledge of both the consequences of concussion and associated return-to-play protocols, both of which could be considered poor. There were no differences in knowledge levels between coaches and referees or between participants with or without a history of concussion. Two-thirds of participants incorrectly believed that headgear could prevent concussion, and nearly 30% of coaches reported having witnessed other coaches allowing a potentially concussed player to continue playing. Conclusions Identification of several misconceptions indicates that concussion management within Welsh amateur rugby union needs to be improved, warranting a multi-faceted educational intervention