38 research outputs found

    Two Skyrmion Dynamics with Omega Mesons

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    We present our first results of numerical simulations of two skyrmion dynamics using an ω\omega-meson stabilized effective Lagrangian. We consider skyrmion-skyrmion scattering with a fixed initial velocity of β=0.5\beta=0.5, for various impact parameters and groomings. The physical picture that emerges is surprisingly rich, while consistent with previous results and general conservation laws. We find meson radiation, skyrmion scattering out of the scattering plane, orbiting and capture to bound states.Comment: 19 pages, 22 figure

    Decompression of Multimorbidity Along the Disease Trajectories of Diabetes Mellitus Patients

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    Multimorbidity, the presence of two or more diseases in a patient, is maybe the greatest health challenge for the aging populations of many high-income countries. One of the main drivers of multimorbidity is diabetes mellitus (DM) due to its large number of risk factors and complications. Yet, we currently have very limited understanding of how to quantify multimorbidity beyond a simple counting of diseases and thereby inform prevention and intervention strategies tailored to the needs of elderly DM patients. Here, we conceptualize multimorbidity as typical temporal progression patterns of multiple diseases, so-called trajectories, and develop a framework to perform a matched and sex-specific comparison between DM and non-diabetic patients. We find that these disease trajectories can be organized into a multi-level hierarchy in which DM patients progress from relatively healthy states with low mortality to high-mortality states characterized by cardiovascular diseases, chronic lower respiratory diseases, renal failure, and different combinations thereof. The same disease trajectories can be observed in non-diabetic patients, however, we find that DM patients typically progress at much higher rates along their trajectories. Comparing male and female DM patients, we find a general tendency that females progress faster toward high multimorbidity states than males, in particular along trajectories that involve obesity. Males, on the other hand, appear to progress faster in trajectories that combine heart diseases with cerebrovascular diseases. Our results show that prevention and efficient management of DM are key to achieve a compression of morbidity into higher patient ages. Multidisciplinary efforts involving clinicians as well as experts in machine learning and data visualization are needed to better understand the identified disease trajectories and thereby contribute to solving the current multimorbidity crisis in healthcare

    Sensitivity of Mountain Wave Drag Estimates on Separation Methods and Proposed Improvements

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    Internal gravity waves (GWs) are ubiquitous in the atmosphere, making significant contributions to the mesoscale motions. Since the majority of their spectrum is unresolved in global circulation models, their effects need to be parameterized. In recent decades GWs have been increasingly studied in high-resolution simulations, which, unlike direct observations, allow us to explore full spatio-temporal variations of the resolved wave field. In our study we analyze and refine a traditional method for GW analysis in a high-resolution simulation on a regional domain around the Drake Passage. We show that GW momentum drag estimates based on the Gaussian high-pass filter method applied to separate GW perturbations from the background are sensitive to the choice of a cutoff parameter. The impact of the cutoff parameter is higher for horizontal fluxes of horizontal momentum, which indicates higher sensitivity for horizontally propagating waves. Two modified methods, which choose the parameter value from spectral information, are proposed. The dynamically determined cutoff is mostly higher than the traditional cutoff values around 500 km, leading to larger GW fluxes and drag, and varies with time and altitude. The differences between the traditional and the modified methods are especially pronounced during events with significant drag contributions from horizontal momentum fluxes

    Gravity waves excited during a minor sudden stratospheric warming

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    An exceptionally deep upper-air sounding launched from Kiruna airport (67.82 degrees N, 20.33 degrees E) on 30 January 2016 stimulated the current investigation of internal gravity waves excited during a minor sudden stratospheric warming (SSW) in the Arctic winter 2015/16. The analysis of the radiosonde profile revealed large kinetic and potential energies in the upper stratosphere without any simultaneous enhancement of upper tropospheric and lower stratospheric values. Upward-propagating inertia-gravity waves in the upper stratosphere and downward-propagating modes in the lower stratosphere indicated a region of gravity wave generation in the stratosphere. Two-dimensional wavelet analysis was applied to vertical time series of temperature fluctuations in order to determine the vertical propagation direction of the stratospheric gravity waves in 1-hourly high-resolution meteorological analyses and short-term forecasts. The separation of upward- and downward-propagating waves provided further evidence for a stratospheric source of gravity waves. The scale-dependent decomposition of the flow into a balanced component and inertia-gravity waves showed that coherent wave packets preferentially occurred at the inner edge of the Arctic polar vortex where a sub-vortex formed during the minor SSW

    Skyrmion-anti-Skyrmion Annihilation with Omega Mesons

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    We study numerically the annihilation of an omega-stabilized Skyrmion and an anti-Skyrmion in three spatial dimensions. To our knowledge this is a first successful simulation of Skyrmion-anti-Skyrmion annihilation which follows through to the point where the energy is carried by outgoing meson waves. We encounter instabilities similar to those encountered is earlier calculations, but in our case these are not fatal and we are able to simulate through this process with a global energy loss of less than 8%, and to identify robust features of the final radiation pattern. The system passes through a singular configuration at the time of half-annihilation. This is followed by the onset of fast oscillations which are superimposed on the smoother process which leads to the appearence of outgoing spherical waves. We investigate the two prominent features of this process, the proliferation of small, fast oscillations, and the singular intermediate configuration. We find that our equations of motion allow for a regime in which the amplitude of certain small perturbations increases exponentially. This regime is similar but not identical to the situation pointed out earlier regarding the original Skyrme model. We argue that the singularity may be seen as the result of a pinch effect similar to that encountered in plasmas.Comment: 26 pages, 15 figure

    Clinical Outcomes of 2-Drug Regimens vs 3-Drug Regimens in Antiretroviral Treatment–Experienced People Living With Human Immunodeficiency Virus

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    BACKGROUND: Limited data exist comparing clinical outcomes of two-drug regimens (2DRs) and three-drug regimens (3DRs) in people living with HIV. METHODS: Antiretroviral treatment-experienced individuals in RESPOND switching to a new 2DR or 3DR from 1/1/12-1/10/18 were included. The incidence of clinical events (AIDS, non-AIDS cancer, cardiovascular disease, end-stage liver and renal disease, death) was compared between regimens using Poisson regression. RESULTS: Of 9791 individuals included, 1088 (11.1%) started 2DRs and 8703 (88.9%) 3DRs. The most common 2DRs were dolutegravir plus lamivudine (22.8%) and raltegravir plus boosted darunavir (19.8%); the most common 3DR was dolutegravir plus 2 nucleoside reverse transcriptase inhibitors (46.9%). Individuals on 2DRs were older (median 52.6 years [interquartile range 46.7-59.0] vs 47.7 [39.7-54.3]), and a higher proportion had ≥1 comorbidity (81.6% vs 73.9%).There were 619 events during 27,159 person-years of follow-up (PYFU): 540 (incidence rate [IR] 22.5/1000 PYFU [95% CI 20.7-24.5]) on 3DRs, 79 (30.9/1000 PYFU [24.8-38.5]) on 2DRs. The most common events were death (7.5/1000 PYFU [95% CI 6.5-8.6]) and non-AIDS cancer (5.8/1000 PYFU [4.9-6.8]). After adjustment for baseline demographic and clinical characteristics, there was a similar incidence of events on both regimen types (2DRs vs 3DRs IR ratio: 0.92 [0.72-1.19]; p=0.53). CONCLUSIONS: This is the first large, international cohort assessing clinical outcomes on 2DRs. After accounting for baseline characteristics, there was a similar incidence of events on 2DRs and 3DRs. 2DRs appear to be a viable treatment option with regard to clinical outcomes; further research on resistance barriers and long-term durability of 2DRs is needed

    Establishing a hepatitis C continuum of care among HIV/hepatitis C virus-coinfected individuals in EuroSIDA

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    Objectives The aim of the study was to establish a methodology for evaluating the hepatitis C continuum of care in HIV/hepatitis C virus (HCV)-coinfected individuals and to characterize the continuum in Europe on 1 January 2015, prior to widespread access to direct-acting antiviral (DAA) therapy. Methods Stages included in the continuum were as follows: anti-HCV antibody positive, HCV RNA tested, currently HCV RNA positive, ever HCV RNA positive, ever received HCV treatment, completed HCV treatment, follow-up HCV RNA test, and cure. Sustained virological response (SVR) could only be assessed for those with a follow-up HCV RNA test and was defined as a negative HCV RNA result measured > 12 or 24 weeks after stopping treatment. Results Numbers and percentages for the stages of the HCV continuum of care were as follows: anti-HCV positive (n = 5173), HCV RNA tested (4207 of 5173; 81.3%), currently HCV RNA positive (3179 of 5173; 61.5%), ever HCV RNA positive (n = 3876), initiated HCV treatment (1693 of 3876; 43.7%), completed HCV treatment (1598 of 3876; 41.2%), follow-up HCV RNA test to allow SVR assessment (1195 of 3876; 30.8%), and cure (629 of 3876; 16.2%). The proportion that achieved SVR was 52.6% (629 of 1195). There were significant differences between regions at each stage of the continuum (P <0.0001). Conclusions In the proposed HCV continuum of care for HIV/HCV-coinfected individuals, we found major gaps at all stages, with almost 20% of anti-HCV-positive individuals having no documented HCV RNA test and a low proportion achieving SVR, in the pre-DAA era.Peer reviewe

    Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study.

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    Determinants of perceived health and unmet healthcare needs in universal healthcare systems with high gender equality

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    Background: Patient attitudes about health and healthcare have emerged as important outcomes to assess in clinical studies. Gender is increasingly recognized as an intersectional social construct that may influence health. Our objective was to determine potential sex differences in self-reported overall health and access to healthcare and whether those differences are influenced by individual social factors in two relatively similar countries. Methods: Two public health surveys from countries with high gender equality (measured by UN GII) and universal healthcare systems, Canada (CCHS2014, n = 57,041) and Austria (AT-HIS2014, n = 15,212), were analysed. Perceived health was assessed on a scale of 1 (very bad) to 4 (very good) and perceived unmet healthcare needs was reported as a dichotomous variable (yes/no). Interactions between sex and social determinants (i.e. employment, education level, immigration and marital status) on outcomes were analysed. Results: Individuals in both countries reported high perceived health (Scoring &gt; 2, 85.0% in Canada, 79.9% in Austria) and a low percentage reported unmet healthcare needs (4.6% in Canada, 10.7% in Austria). In both countries, sex and several social factors were associated with high perceived health, and a sex-by-marital status interaction was observed, with a greater negative impact of divorce for men. Female sex was positively associated with unmet care needs in both countries, and sex-by-social factors interactions were only detected in Canada. Conclusions: The intersection of sex and social factors in influencing patient-relevant outcomes varies even among countries with similar healthcare and high gender equality

    Sex, Gender, and Cardiovascular Health in Canadian and Austrian Populations

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    Background: Evidence differentiating the effect of biological sex from psychosociocultural factors (gender) in different societies and its relation to cardiovascular diseases is scarce. We explored the association between sex, gender, and cardiovascular health (CVH) among Canadian (CAN) and Austrian (AT) populations. Methods: The Canadian Community Health Survey (CCHS) (n = 63,522; 55% female) and Austrian Health Interview Survey (AT-HIS) (n = 15,771; 56% female) were analyzed in a cross-sectional survey design. The CANHEART/ATHEART index, a measure of ideal CVH composed of 6 cardiometabolic risk factors (smoking, physical activity, fruit and vegetable consumption, overweight/obesity, diabetes, and hypertension; range 0-6; higher scores reflecting better CVH) was calculated for both databases. A composite measure of psychosociocultural gender was computed for each country (range 0-1, higher score identifying characteristics traditionally ascribed to women). Results: Median CANHEART 4 (interquartile range 3-5) and CAN gender scores 0.55 (0.49-0.60) were similar to median ATHEART 4 (3-5) and AT gender scores 0.55 (0.46-0.64). Although higher gender scores (CCHS: β = −1.33, 95% confidence interval [CI] −1.44 to −1.22; AT-HIS: β = −1.08, 95% CI −1.26 to −0.89)) were associated with worse CVH, female sex (CCHS: β = 0.35, 95% CI (0.33-0.37); AT-HIS: β = 0.60, 95% CI (0.55-0.64)) was associated with better CVH in both populations. In addition, higher gender scores were associated with increased prevalence of heart disease compared with female sex. The magnitude of this risk was higher in Austrians. Conclusions: These results demonstrate that individuals with characteristics typically ascribed to women reported poorer cardiovascular health and higher risk of heart disease, independently from biological sex and baseline CV risk factors, in both countries. Female sex exhibited better CV health and a lower prevalence of heart disease than male in both populations. However, gender factors and magnitude of gender impact varied by country
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