3,283 research outputs found
Dynamical stability of a doubly quantized vortex in a three-dimensional condensate
The Bogoliubov equations are solved for a three-dimensional Bose-Einstein
condensate containing a doubly quantized vortex, trapped in a harmonic
potential. Complex frequencies, signifying dynamical instability, are found for
certain ranges of parameter values. The existence of alternating windows of
stability and instability, respectively, is explained qualitatively and
quantitatively using variational calculus and direct numerical solution. It is
seen that the windows of stability are much smaller for a cigar shaped
condensate than for a pancake shaped one, which is consistent with the findings
of recent experiments.Comment: 23 pages, 11 figure
Phase diagram of multiferroic KCuAsO(OD)
The layered compound KCuAsO(OD), comprising distorted kagome
planes of Cu ions, is a recent addition to the family of type-II
multiferroics. Previous zero field neutron diffraction work has found two
helically ordered regimes in \kns, each showing a distinct coupling between the
magnetic and ferroelectric order parameters. Here, we extend this work to
magnetic fields up to ~T using neutron powder diffraction, capacitance,
polarization, and high-field magnetization measurements, hence determining the
phase diagram. We find metamagnetic transitions in both low temperatures
phases around ~T, which neutron powder diffraction reveals
to correspond to a rotation of the helix plane away from the easy plane, as
well as a small change in the propagation vector. Furthermore, we show that the
sign of the ferroelectric polarization is reversible in a magnetic field,
although no change is observed (or expected on the basis of the magnetic
structure) due to the transition at ~T. We finally justify the temperature
dependence of the polarization in both zero-field ordered phases by a symmetry
analysis of the free energy expansion
Estimating the burden of minor ailment consultations in general practices and emergency departments through retrospective review of routine data in North East Scotland
Minor ailment attendances in general practices and emergency departments (EDs) place significant burden on health care resources
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Simulations of high yield air bursts using gray and multigroup diffusion; Comparison of Raptor and Lasnex
Superconformal constraints for QCD conformal anomalies
Anomalous superconformal Ward identities and commutator algebra in N = 1
super-Yang-Mills theory give rise to constraints between the QCD special
conformal anomalies of conformal composite operators. We evaluate the
superconformal anomalies that appear in the product of renormalized conformal
operators and the trace anomaly in the supersymmetric spinor current and check
the constraints at one-loop order. In this way we prove the universality of QCD
conformal anomalies, which define the non-diagonal part of the anomalous
dimension matrix responsible for scaling violations of exclusive QCD amplitudes
at the next-to-leading order.Comment: 30 pages, 2 figures, LaTe
A comparison of analytical approaches to investigate associations for accelerometry-derived physical activity spectra with health and developmental outcomes in children
Under embargo until: 2021-09-20The use of high-resolution physical activity intensity spectra obtained from accelerometry can improve knowledge of associations with health and development beyond the use of traditional summary measures of intensity. The aim of the present study was to compare three different approaches for determining associations for spectrum descriptors of physical activity (the intensity gradient, principal component analysis, and multivariate pattern analysis) with relevant outcomes in children. We used two datasets including physical activity spectrum data (ActiGraph GT3X+) and 1) a cardiometabolic health outcome in 841 schoolchildren and 2) a motor skill outcome in 1081 preschool children. We compared variance explained (R2) and associations with the outcomes for the intensity gradient (slope) across the physical activity spectra, a two-component principal component model describing the physical activity variables, and multivariate pattern analysis using the intensity spectra as the explanatory data matrices. Results were broadly similar for all analytical approaches. Multivariate pattern analysis explained the most variance in both datasets, likely resulting from use of more of the information available from the intensity spectra. Yet, volume and intensity dimensions of physical activity are not easily disentangled and their relative importance may be interpreted differently using different methodology.acceptedVersio
Maintaining intravenous volume mitigates hypothermia-induced myocardial dysfunction and accumulation of intracellular Ca2+
Previous research exploring pathophysiological mechanisms underlying circulatory collapse after rewarming victims of severe accidental hypothermia has documented post-hypothermic cardiac dysfunction and hypothermia-induced elevation of intracellular Ca2+ concentration ([Ca2+]i) in myocardial cells. The aim of the present study was to examine if maintaining euvolaemia during rewarming mitigates cardiac dysfunction and/or normalizes elevated myocardial [Ca2+]i. A total of 21 male Wistar rats (300 g) were surface cooled to 15◦C, then maintained at 15◦C for 4 h, and subsequently rewarmed to 37◦C. The rats were randomly assigned to one of three groups: (1) non-intervention control (n = 7), (2) dextran treated (i.v. 12 ml/kg dextran 70; n = 7), or (3) crystalloid treated (24 ml/kg 0.9% i.v. saline; n = 7). Infusions occurred during the first 30 min of rewarming. Arterial blood pressure, stroke volume (SV), cardiac output (CO), contractility (dP/dtmax) and blood gas changes were measured. Post-hypothermic changes in [Ca2+]i were measured using the method of radiolabelled Ca2+ ( 45Ca2+). Untreated controls displayed post-hypothermic cardiac dysfunction with significantly reduced CO, SV and dP/dtmax. In contrast, rats receiving crystalloid or dextran treatment showed a return to pre-hypothermic control levels of CO and SV after rewarming, with the dextran group displaying significantly better amelioration of post-hypothermic cardiac dysfunction than the crystalloid group. Compared to the post-hypothermic increase in myocardial [Ca2+]i in non-treated controls, [Ca2+]i values with crystalloid and dextran did not increase to the same extent after rewarming. Volume replacement with crystalloid or dextran during rewarming abolishes posthypothermic cardiac dysfunction, and partially mitigates the hypothermia-induced elevation of [Ca2+]i
Warming of Atlantic Water in two west Spitsbergen fjords over the last century (1912-2009)
The recently observed warming of west Spitsbergen fjords has led to anomalous sea-ice conditions and has implications for the marine ecosystem. We investigated long-term trends of maximum temperature of Atlantic Water (AW) in two west Spitsbergen fjords. The data set is composed of more than 400 oceanographic stations for Isfjorden and Grønfjorden (78.1°N), spanning from 1876 to 2009. Trends throughout the last century (1912–2009) indicate an increase of 1.9°C and 2.1°C in the maximum temperature during autumn for Isfjorden and Grønfjorden, respectively. A recent warming event in the beginning of the 21st century is found to be more than 1°C higher than the second warmest period in the time series. Mean sea-level pressure (MSLP) data from ERA-40 and ERA-Interim data sets produced by the European Centre for Medium-Range Weather Forecasts and mean temperature in the core of the West Spitsbergen Current (WSC) at the Sørkapp Section along 76.3°N were used to explain the variability of the maximum temperature. A correlation analysis confirmed previous findings, showing that variability in the oceanography of the fjords can be explained mainly by two external factors: AW temperature variability in the WSC and regional patterns of the wind stress field. To take both processes into consideration, a multiple regression model accounting for temperature in the WSC core and MSLP over the area was developed. The predicted time series shows a reasonable agreement with observed maxima temperature in Isfjorden for the period 1977–2009 (N=24), with a statistically significant multiple correlation coefficient of 0.60 (R2=0.36) at P<0.05.publishedVersio
Use of Complementary and Alternative Medicine in the context of cancer; prevalence, reasons for use, disclosure, information received, risks and benefits reported by people with cancer in Norway
Background Research exploring the use of specific Complementary and Alternative Medicine (CAM) modalities by Norwegian cancer patients is sparse. The aims of this study were therefor to map the different CAM modalities cancer patients use and further investigate their rationale for use, communication about use, self-reported benefits and harms, and their sources of information about the different modalities. Methods In cooperation with the Norwegian Cancer Society (NCS), we conducted an online cross-sectional study among members of their user panel with present or previously cancer (n = 706). The study was carried out in September/October 2021 using a modified cancer-specific version of the International Questionnaire to Measure Use of Complementary and Alternative Medicine (I-CAM-Q). In total, 468 members, 315 women and 153 men, agreed to participate resulting in a response rate of 67.2%. The study was reported in accordance with the National Research Center in Complementary and Alternative Medicine’s (NAFKAM) model of reporting CAM use. Results A large proportion of the participants (79%, n = 346) had used some form of CAM with a mean of 3.8 modalities each (range 1-17); 33% (n = 143) had seen a CAM provider, 52% (n = 230) had used natural remedies, while 58% (n = 253) had used self-help practices. Most of the participants used CAM to increase their quality of life, cope with the cancer disease or for relaxation/well-being (64%-94%), mostly with high satisfaction and low rates of adverse effects. Few used CAM to treat cancer or prevent it from spreading (16%, n = 55). The main information sources were health care providers (47%), the internet (47%), and family and friends (39%). More than half (59%) of the cancer patients discussed their use of at least one CAM modality with a physician. Conclusions The results of this survey will provide health professionals with more in-depth insight into the patterns of CAM use by cancer patients and facilitate better-informed discussions with their patients. Considering the high use of CAM, reliable information provision supporting cancer care providers’ knowledge and health literacy among patients as well as good communication are crucial. The cooperation between the NCS and NAFKAM provides an example of how to address these issues
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