Stratifying quotient stacks and moduli stacks

Recent results in geometric invariant theory (GIT) for non-reductive linear algebraic group actions allow us to stratify quotient stacks of the form [X/H], where X is a projective scheme and H is a linear algebraic group with internally graded unipotent radical acting linearly on X, in such a way that each stratum [S/H] has a geometric quotient S/H. This leads to stratifications of moduli stacks (for example, sheaves over a projective scheme) such that each stratum has a coarse moduli space.Comment: 25 pages, submitted to the Proceedings of the Abel Symposium 201

High Prudent diet factor score predicts lower relapse hazard in early multiple sclerosis

Background: Dietary patterns and their association with subsequent clinical course have not been well studied in early multiple sclerosis (MS). Objectives: To describe dietary patterns in people in 5 years following first clinical demyelination and assess associations with MS conversion and relapse. Methods: This study included baseline food frequency questionnaire dietary intake (entry to the Ausimmune Study) and 5-year follow-up; iterated principal factor analysis was applied. MS conversion and relapse risks were assessed by Cox proportional hazards models, adjusted for age, sex, study site, education, body mass index (BMI), smoking and omega-3 supplement use. Results: In cases with a first clinical diagnosis of central nervous system (CNS) demyelination, we identified three major dietary patterns, 'Prudent', 'High-Vegetable' and 'Mixed', explaining 43%, 37% and 24% of diet variance in dietary intake, respectively. Fruits, vegetables, fish, wholegrains and nuts loaded highly on the Prudent pattern, starchy vegetables and legumes on the High-Vegetable pattern, and meats and alcohol on the Mixed pattern. Diet factor scores were not associated with MS conversion risk. Those with baseline Prudent scores above the median had significantly lower relapse risk (adjusted hazard ratio = 0.54, 95% confidence interval (CI) 0.37, 0.81) with some evidence of a plateau effect. Conclusion: Prudent diet factor score above the median was prospectively associated with lower relapse risk in the 5 years following the first clinical demyelinating event

Pica and refractory iron deficiency anaemia: a case report

INTRODUCTION: Iron deficiency is the most common cause of anaemia worldwide. Pica, the ingestion of substances that are inappropriate for consumption, is associated with iron deficiency and may be under-diagnosed. CASE PRESENTATION: A 34-year-old woman presented with iron deficiency anaemia refractory to treatment for more than a decade. The clinical presentation, endoscopic findings and laboratory investigations were consistent with pica. Subsequent geophysical analysis confirmed that the ingested material was kaolin, a negatively charged silicate. CONCLUSION: Prolonged unexplained iron deficiency anaemia should prompt clinicians to remember and inquire about pica. In our patient, this would have averted numerous unnecessary investigations and prevented a decade-long suffering

Gender perspectives on views and preferences of older people on exercise to prevent falls: a systematic mixed studies review

Background: To offer fall prevention exercise programs that attract older people of both sexes there is a need to understand both womens and mens views and preferences regarding these programs. This paper aims to systematically review the literature to explore any underlying gender perspectives or gender interpretations on older peoples views or preferences regarding uptake and adherence to exercise to prevent falls. Methods: A review of the literature was carried out using a convergent qualitative design based on systematic searches of seven electronic databases (PubMed, CINAHL, Amed, PsycINFO, Scopus, PEDro, and OTseeker). Two investigators identified eligible studies. Each included article was read by at least two authors independently to extract data into tables. Views and preferences reported were coded and summarized in themes of facilitators and barriers using a thematic analysis approach. Results: Nine hundred and nine unique studies were identified. Twenty five studies met the criteria for inclusion. Only five of these contained a gender analysis of mens and womens views on fall prevention exercises. The results suggests that both women and men see women as more receptive to and in more need of fall prevention messages. The synthesis from all 25 studies identified six themes illustrating facilitators and six themes describing barriers for older people either starting or adhering to fall prevention exercise. The facilitators were: support from professionals or family; social interaction; perceived benefits; a supportive exercise context; feelings of commitment; and having fun. Barriers were: practical issues; concerns about exercise; unawareness; reduced health status; lack of support; and lack of interest. Considerably more women than men were included in the studies. Conclusion: Although there is plenty of information on the facilitators and barriers to falls prevention exercise in older people, there is a distinct lack of studies investigating differences or similarities in older womens and mens views regarding fall prevention exercise. In order to ensure that fall prevention exercise is appealing to both sexes and that the inclusion of both men and women are encouraged, more research is needed to find out whether gender differences exists and whether practitioners need to offer a range of opportunities and support strategies to attract both women and men to falls prevention exercise.Funding Agencies|Swedish Research Council [2015-03481]; Strategic Research Programme in Care Sciences, Umea University; Karolinska Institute, Sweden; Umea University</p

Complementary and alternative medicines (CAMs) and adherence to mental health medications

BACKGROUND: Medication regimes are often poorly adhered to, and the negative consequences of this are well recognised. The dynamics underlying non-adherence are less understood. This paper examines adherence to prescription medications for mental health difficulties in relation to the use of complementary and alternative medicines (CAMs). This was based on suggestions that within medical pluralism, CAMs may reduce adherence to conventional prescription medications for reasons such as their further complicating the medication regime or their being perceived as a substitute with less adverse side effects than conventional prescription medications. METHODS: Data used was from the National Comorbidity Study Replication (NCS-R), specifically those 1396 individuals who reported taking a prescription drug for mental health difficulties within the last 12 months and under the supervision of a health professional. This subsample was selected due to their being the only subgroup questioned regarding their medication adherence. Other demographic and health factors were also considered. RESULTS: The use of complementary medicines alongside the conventional medicines bore no significant relation to odds of reporting adherence versus non adherence. Ethnicity and medication count were significant predictors of adherence versus non-adherence. CONCLUSIONS: The above findings are discussed from the point of both promoting the use of CAMs and increasing health professionals’ understanding of the dynamics underlying adherence, or the lack thereof, and subsequently informing interventions to reduce the problems associated with this issue in terms of increased health care needs and reduced quality of life

Coverage, Continuity and Visual Cortical Architecture

The primary visual cortex of many mammals contains a continuous representation of visual space, with a roughly repetitive aperiodic map of orientation preferences superimposed. It was recently found that orientation preference maps (OPMs) obey statistical laws which are apparently invariant among species widely separated in eutherian evolution. Here, we examine whether one of the most prominent models for the optimization of cortical maps, the elastic net (EN) model, can reproduce this common design. The EN model generates representations which optimally trade of stimulus space coverage and map continuity. While this model has been used in numerous studies, no analytical results about the precise layout of the predicted OPMs have been obtained so far. We present a mathematical approach to analytically calculate the cortical representations predicted by the EN model for the joint mapping of stimulus position and orientation. We find that in all previously studied regimes, predicted OPM layouts are perfectly periodic. An unbiased search through the EN parameter space identifies a novel regime of aperiodic OPMs with pinwheel densities lower than found in experiments. In an extreme limit, aperiodic OPMs quantitatively resembling experimental observations emerge. Stabilization of these layouts results from strong nonlocal interactions rather than from a coverage-continuity-compromise. Our results demonstrate that optimization models for stimulus representations dominated by nonlocal suppressive interactions are in principle capable of correctly predicting the common OPM design. They question that visual cortical feature representations can be explained by a coverage-continuity-compromise.Comment: 100 pages, including an Appendix, 21 + 7 figure

SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). IV. Spatial Clustering and Halo Masses of Submillimeter Galaxies

We analyze an extremely deep 450 μm image (1σ = 0.56 mJy beam−1) of a sime300 arcmin2 area in the CANDELS/COSMOS field as part of the Sub-millimeter Common User Bolometric Array-2 Ultra Deep Imaging EAO Survey. We select a robust (signal-to-noise ratio ≥4) and flux-limited (≥4 mJy) sample of 164 submillimeter galaxies (SMGs) at 450 μm that have K-band counterparts in the COSMOS2015 catalog identified from radio or mid-infrared imaging. Utilizing this SMG sample and the 4705 K-band-selected non-SMGs that reside within the noise level ≤1 mJy beam−1 region of the 450 μm image as a training set, we develop a machine-learning classifier using K-band magnitude and color–color pairs based on the 13-band photometry available in this field. We apply the trained machine-learning classifier to the wider COSMOS field (1.6 deg2) using the same COSMOS2015 catalog and identify a sample of 6182 SMG candidates with similar colors. The number density, radio and/or mid-infrared detection rates, redshift and stellar-mass distributions, and the stacked 450 μm fluxes of these SMG candidates, from the S2COSMOS observations of the wide field, agree with the measurements made in the much smaller CANDELS field, supporting the effectiveness of the classifier. Using this SMG candidate sample, we measure the two-point autocorrelation functions from z = 3 down to z = 0.5. We find that the SMG candidates reside in halos with masses of sime(2.0 ± 0.5) × 1013 h −1 M ☉ across this redshift range. We do not find evidence of downsizing that has been suggested by other recent observational studies