Electronic spin-triplet nematic with a twist

We analyze a model of itinerant electrons interacting through a quadrupole density-density repulsion in three dimensions. At the mean field level, the interaction drives a continuous Pomeranchuk instability towards $d$-wave, spin-triplet nematic order, which simultaneously breaks the SU(2) spin-rotation and spatial rotational symmetries. This order results in spin antisymmetric, elliptical deformations of the Fermi surfaces of up and down spins. We show that the effects of quantum fluctuations are similar to those in metallic ferromagnets, rendering the nematic transition first-order at low temperatures. Using the fermionic quantum order-by-disorder approach to self-consistently calculate fluctuations around possible modulated states, we show that the first-order transition is pre-empted by the formation of a nematic state that is intertwined with a helical modulation in spin space. Such a state is closely related to $d$-wave bond density wave order in square-lattice systems. Moreover, we show that it may coexist with a modulated, $p$-wave superconducting state.Comment: 15 pages, 9 figure

The Geometric Phase in Supersymmetric Quantum Mechanics

We explore the geometric phase in N=(2,2) supersymmetric quantum mechanics. The Witten index ensures the existence of degenerate ground states, resulting in a non-Abelian Berry connection. We exhibit a non-renormalization theorem which prohibits the connection from receiving perturbative corrections. However, we show that it does receive corrections from BPS instantons. We compute the one-instanton contribution to the Berry connection for the massive CP^1 sigma-model as the potential is varied. This system has two ground states and the associated Berry connection is the smooth SU(2) 't Hooft-Polyakov monopole.Comment: 28 pages, 2 figures, references added. v2: clarification of possible corrections to Abelian Berry phase. v3: footnotes added to point the reader towards later development

Short period forecasting of catchment-scale precipitation. Part I: the role of Numerical Weather Prediction

International audienceA deterministic forecast of surface precipitation involves solving a time-dependent moisture balance equation satisfying conservation of total water substance. A realistic solution needs to take into account feedback between atmospheric dynamics and the diabatic sources of heat energy associated with phase changes, as well as complex microphysical processes controlling the conversion between cloud water (or ice) and precipitation. Such processes are taken into account either explicitly or via physical parameterisation schemes in many operational numerical weather prediction models; these can therefore generate precipitation forecasts which are fully consistent with the predicted evolution of the atmospheric state as measured by observations of temperature, wind, pressure and humidity. This paper reviews briefly the atmospheric moisture balance equation and how it may be solved in practice. Solutions are obtained using the Meteorological Office Mesoscale version of its operational Unified Numerical Weather Prediction (NWP) model; they verify predicted precipitation rates against catchment-scale values based on observations collected during an Intensive Observation Period (IOP) of HYREX. Results highlight some limitations of an operational NWP forecast in providing adequate time and space resolution, and its sensitivity to initial conditions. The large-scale model forecast can, nevertheless, provide important information about the moist dynamical environment which could be incorporated usefully into a higher resolution, ?storm-resolving' prediction scheme. Keywords: Precipitation forecasting; moisture budget; numerical weather prediction</p

Non-optimal apparent temperature and cardiovascular mortality: the association in Puducherry, India between 2011 and 2020

BACKGROUND: Cardiovascular diseases (CVDs), the leading cause of death worldwide, are sensitive to temperature. In light of the reported climate change trends, it is important to understand the burden of CVDs attributable to temperature, both hot and cold. The association between CVDs and temperature is region-specific, with relatively few studies focusing on low-and middle-income countries. This study investigates this association in Puducherry, a district in southern India lying on the Bay of Bengal, for the first time. METHODS: Using in-hospital CVD mortality data and climate data from the Indian Meteorological Department, we analyzed the association between apparent temperature (T(app)) and in-hospital CVD mortalities in Puducherry between 2011 and 2020. We used a case-crossover model with a binomial likelihood distribution combined with a distributed lag non-linear model to capture the delayed and non-linear trends over a 21-day lag period to identify the optimal temperature range for Puducherry. The results are expressed as the fraction of CVD mortalities attributable to heat and cold, defined relative to the optimal temperature. We also performed stratified analyses to explore the associations between T(app) and age-and-sex, grouped and considered together, and different types of CVDs. Sensitivity analyses were performed, including using a quasi-Poisson time-series approach. RESULTS: We found that the optimal temperature range for Puducherry is between 30 degrees C and 36 degrees C with respect to CVDs. Both cold and hot non-optimal T(app) were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Cumulatively, up to 17% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to heat (9.1%) than cold (8.3%). We also found that males were more vulnerable to colder temperature; females above 60 years were more vulnerable to heat while females below 60 years were affected by both heat and cold. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature. CONCLUSION: Both heat and cold contribute to the burden of CVDs attributable to non-optimal temperatures in the tropical Puducherry. Our study also identified the age-and-sex and CVD type differences in temperature attributable CVD mortalities. Further studies from India could identify regional associations, inform our understanding of the health implications of climate change in India and enhance the development of regional and contextual climate-health action-plans

The chiral ring of AdS3/CFT2 and the attractor mechanism

We study the moduli dependence of the chiral ring in N = (4,4) superconformal field theories, with special emphasis on those CFTs that are dual to type IIB string theory on AdS3xS3xX4. The chiral primary operators are sections of vector bundles, whose connection describes the operator mixing under motion on the moduli space. This connection can be exactly computed using the constraints from N = (4,4) supersymmetry. Its curvature can be determined using the tt* equations, for which we give a derivation in the physical theory which does not rely on the topological twisting. We show that for N = (4,4) theories the chiral ring is covariantly constant over the moduli space, a fact which can be seen as a non-renormalization theorem for the three-point functions of chiral primaries in AdS3/CFT2. From the spacetime point of view our analysis has the following applications. First, in the case of a D1/D5 black string, we can see the matching of the attractor flow in supergravity to RG-flow in the boundary field theory perturbed by irrelevant operators, to first order away from the fixed point. Second, under spectral flow the chiral primaries become the Ramond ground states of the CFT. These ground states represent the microstates of a small black hole in five dimensions consisting of a D1/D5 bound state. The connection that we compute can be considered as an example of Berry's phase for the internal microstates of a supersymmetric black hole.Comment: 72 pages (60 + appendices

Assessing the predictive validity of the UCAT — a systematic review and narrative synthesis

Background: The University Clinical Aptitude Test (UCAT) is an admissions assessment used by a consortium of universities across the UK, Australia, and New Zealand, to aid the selection of applicants to medical and dental degree programmes. The UCAT aims to measure the mental aptitude and professional behaviours required to become successful doctors and dentists. We conducted a systematic review to establish the predictive value of the UCAT across measures of performance at undergraduate and post-graduate levels. Methods: A literature search was conducted in April 2020 using eight electronic databases: MEDLINE, APA PsycInfo, SCOPUS, Web of Science, EThOS, OpenGrey, PROSPERO, and the UCAT website. Data were extracted from selected studies and tabulated as results matrices. A narrative synthesis was performed. Results: Twenty-four studies satisfied our inclusion criteria, 23 of which were deemed to be of good quality (using the Newcastle-Ottawa Scale). For over 70% of univariate data points, the UCAT exerted no statistically significant predictive validity; for the remainder, predictive power was weak. The cognitive total and verbal reasoning subtests had the largest evidence base as weakly positive predictors of academic performance. The SJT subtest was a weak predictor of professional behaviour during medical school. Studies specific to dental schools demonstrated variable findings across the five studies. Only 1 study looked at post-graduate outcome measures and demonstrated that the UCAT was not a predictor of health- or conduct-related fitness to practice declarations at GMC registration. Conclusions: These data provide some support for the use of cognitive total and verbal reasoning subtests as part of medical school selection. Further research is needed to investigate outcomes beyond professional registration and for dental students

The association between apparent temperature and hospital admissions for cardiovascular disease in limpopo province, South Africa

Cardiovascular diseases (CVDs) have a high disease burden both globally and in South Africa. They have also been found to be temperature-sensitive globally. The association between temperature and CVD morbidity has previously been demonstrated, but little is known about it in South Africa. It is important to understand how changes in temperature in South Africa will affect CVD morbidity, especially in rural regions, to inform public health interventions and adaptation strategies. This study aimed to determine the short-term effect of apparent temperature (T(app)) on CVD hospital admissions in Mopani District, Limpopo province, South Africa. A total of 3124 CVD hospital admissions records were obtained from two hospitals from 1 June 2009 to 31 December 2016. Daily T(app) was calculated using nearby weather station measurements. The association was modelled using a distributed lag non-linear model with a negative binomial regression over a 21-day lag period. The fraction of morbidity attributable to non-optimal T(app), i.e., cold (6-25 degrees C) and warm (27-32 degrees C) T(app) was reported. We found an increase in the proportion of admissions due to CVDs for warm and cold T(app) cumulatively over 21 days. Increasing CVD admissions due to warm T(app) appeared immediately and lasted for two to four days, whereas the lag-structure for the cold effect was inconsistent. A proportion of 8.5% (95% Confidence Interval (CI): 3.1%, 13.7%) and 1.1% (95% CI: -1.4%, 3.5%) of the total CVD admissions was attributable to cold and warm temperatures, respectively. Warm and cold T(app) may increase CVD admissions, suggesting that the healthcare system and community need to be prepared in the context of global temperature changes

Holographic Josephson Junctions and Berry holonomy from D-branes

We construct a holographic model for Josephson junctions with a defect system of a Dp brane intersecting a D(p+2) brane. In addition to providing a geometrical picture for the holographic dual, this leads us very naturally to suggest the possibility of non-Abelian Josephson junctions characterized in terms of the topological properties of the branes. The difference between the locations of the endpoints of the Dp brane on either side of the defect translates into the phase difference of the condensate in the Josephson junction. We also add a magnetic flux on the D(p+2) brane and allow it evolve adiabatically along a closed curve in the space of the magnetic flux, while generating a non-trivial Berry holonomy.Comment: 20 pages, 2 figure

Temperature and cardiovascular diseases: exploring associations in India and public health insights

Abstract Background Climate change has far-reaching consequences on human health globally. Cardiovascular diseases (CVDs), the global leading cause of death, are climate sensitive, mainly to temperature. The temperature-CVD association is region-specific, with several studies from Europe but relatively few from low-and-middle-income countries (LMICs). Methods We used a binomial regression model to analyze the association between apparent temperature and in-hospital CVD mortality in Puducherry city. A distributed lag non-linear model was used to capture the delayed and non-linear trends over a 21 day lag period to estimate the burden of in-hospital CVD mortalities attributable to non-optimal temperature between 2010 and 2020. Results Tapp in Puducherry ranges from 23°C to 40°C. We found that the optimal temperature range for Puducherry is between 33°C and 35°C with respect to CVDs. Temperatures both above and below the optimal temperature range were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Up to 20% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to cold (11.2%) than heat (9.12%). We also found that males above 60 years of age were more vulnerable to colder temperatures while females above 60 years were more vulnerable to the heat. Mortality with cerebrovascular accidents was associated more with heat compared to cold, and ischemic heart diseases did not seem to be affected by temperature. Conclusions Both cold and heat is associated with CVD mortality in Puducherry. The comparison of the results of this exploratory Indian study with those from European contexts show that the associations differ based on several factors. There are also age, gender and CVD type differences in Tapp attributable CVD mortalities. More region specific studies on Tapp- CVD mortality are needed from LMICs to better understand this association and build capacity. Key messages • The regional burden of cold attributable CVD deaths needs to be considered along with heat. Age and gender specific differences in the association need to be further studied globally. • The development regional and contextual climate-health action plans, as seen in some European countries, could be enhanced by such studies and reduce the burden of temperature attributable CVD deaths

Appendix: Data management and data archive for the HYREX Programme

International audienceSince the mid 1980s, changes in political imperatives plus technological changes in computer hardware and software have heightened the awareness of the economic value and importance of quality datasets to scientific research. The Natural Environment Research Council's (NERC) interdisciplinary Thematic and Special Topic Programmes have highlighted the need for a coherent data management policy to provide and preserve these quality datasets for posterity. The Hydrological Radar EXperiment (HYREX) Special Topic Programme brought together multi-disciplinary researchers from UK public sector laboratories and universities. In this paper, the HYREX data management strategy, its problems and its solutions are discussed. The HYREX data archive, situated at NERC's British Atmospheric Data Centre, is described. Keywords: radar, data, archive, web, storm, flood</p