165 research outputs found

    Random fluctuation leads to forbidden escape of particles

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    A great number of physical processes are described within the context of Hamiltonian scattering. Previous studies have rather been focused on trajectories starting outside invariant structures, since the ones starting inside are expected to stay trapped there forever. This is true though only for the deterministic case. We show however that, under finitely small random fluctuations of the field, trajectories starting inside Arnold-Kolmogorov-Moser (KAM) islands escape within finite time. The non-hyperbolic dynamics gains then hyperbolic characteristics due to the effect of the random perturbed field. As a consequence, trajectories which are started inside KAM curves escape with hyperbolic-like time decay distribution, and the fractal dimension of a set of particles that remain in the scattering region approaches that for hyperbolic systems. We show a universal quadratic power law relating the exponential decay to the amplitude of noise. We present a random walk model to relate this distribution to the amplitude of noise, and investigate this phenomena with a numerical study applying random maps.Comment: 6 pages, 6 figures - Up to date with corrections suggested by referee

    Long-term outcomes of pelvic organ prolapse repair using a mesh-capturing device when comparing single- versus multicenter use

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    Purpose The aim of this study was to compare long-term effects of high-volume surgery at a single-center to multicenter use when using a mesh-capturing device for pelvic organ prolapse (POP) repair. Methods Five years after surgery 101 (88%) at the single center were compared with 164 (81.2%) in the multicenter trial. Outcome measurements included clinical examination, prolapse-specific symptom questionnaires [Pelvic Floor Distress Inventory 20 (PFDI-20), Pelvic Floor Impact Questionnaire-short form (PFIQ-7), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12)] and pain estimation by VAS (0-10). Results Optimal apical segment outcome was 95% in the single- compared to 83.3% in the multicenter study (p = 0) was more common at the multicenter as compared to the single center [(19.8% vs 5.4%) and (26% vs 2.7%), (p <0.001)]. Reoperations for POP and mesh-related complications were more frequent in the multicenter study [31/202 (15.3%) vs 7/116 (6.1%),p <0.001]. Total PFDI-20, PFIQ-7 and PISQ-12 scores were comparable between the cohorts. There were no significant differences in overall pain scores in-between the cohorts during follow-up. At the single center, 1/81 patients (1.2%) had VAS 7/10, i.e. severe pain, as compared to 3/131 (2.3%) in the multicenter study (p = 0.277). Conclusions Despite the high objective and subjective long-term effectiveness of the procedure in both regular use, and at a high-volume center, centralizing the use of a standardized capturing-device guided transvaginal mesh for POP repair reduced secondary interventions by more than half.Peer reviewe

    Quality of life after Uphold (TM) Vaginal Support System surgery for apical pelvic organ prolapse-A prospective multicenter study

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    Objective: To study the effects on quality of life in women operated for apical pelvic organ prolapse using the Vaginal Uphold (TM) System. Study design: In this prospective cohort study, women (n = 207) with symptomatic apical prolapse, with or without cystocele, were operated using the Uphold (TM) Vaginal Support System. Follow-up for quality of life was performed at 12 months after surgery, and assessed by the PFDI-20, and PFIQ-7, and sexual function by the PISQ-12. We used odds ratios (ORs) with 95% confidence intervals (CIs) for outcome association analyses using logistic regression. Results: At one-year follow-up majority of women experienced an overall postoperative improvement in quality of life (p <0.001). One year after surgery Uphold (TM) operation alone increased the risk for prolapse related bother as compared to Uphold (TM) combined with anterior colporraphy (POP-IQ-7; OR 2.1; 95% CI 1.01-4.3). The frequency of dyspareunia decreased postoperatively (p = 0.004), however, after one-year, overall sexual function deteriorated significantly (p <0.001). The worsening in sexual function scores was mainly attributed to the partner related domain, whereas the behavioral-emotive and physical domains showed no significant changes. Conclusion: Apical prolapse repair using Uphold (TM) improved quality of life among our patients but worsened overall sexual function postoperatively. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

    Nonconcave entropies in multifractals and the thermodynamic formalism

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    We discuss a subtlety involved in the calculation of multifractal spectra when these are expressed as Legendre-Fenchel transforms of functions analogous to free energy functions. We show that the Legendre-Fenchel transform of a free energy function yields the correct multifractal spectrum only when the latter is wholly concave. If the spectrum has no definite concavity, then the transform yields the concave envelope of the spectrum rather than the spectrum itself. Some mathematical and physical examples are given to illustrate this result, which lies at the root of the nonequivalence of the microcanonical and canonical ensembles. On a more positive note, we also show that the impossibility of expressing nonconcave multifractal spectra through Legendre-Fenchel transforms of free energies can be circumvented with the help of a generalized free energy function, which relates to a recently introduced generalized canonical ensemble. Analogies with the calculation of rate functions in large deviation theory are finally discussed.Comment: 9 pages, revtex4, 3 figures. Changes in v2: sections added on applications plus many new references; contains an addendum not contained in published versio

    Genetic components of functional connectivity in the brain: the heritability of synchronization likelihood

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    Cognitive functions require the integrated activity of multiple specialized, distributed brain areas. Such functional coupling depends on the existence of anatomical connections between the various brain areas as well as physiological processes whereby the activity in one area influences the activity in another area. Recently, the Synchronization Likelihood (SL) method was developed as a general method to study both linear and nonlinear aspects of coupling. In the present study the genetic architecture of the SL in different frequency bands was investigated. Using a large genetically informative sample of 569 subjects from 282 extended twin families we found that the SL is moderately to highly heritable (41-67%) especially in the alpha frequency (8-13 Hz) range. This index of functional connectivity of the brain has been associated with a number of pathological states of the brain. The significant heritability found here suggests that SL can be used to examine the genetic susceptibility to these condition

    Dominance and parent-of-origin effects of coding and non-coding alleles at the acylCoA-diacylglycerol-acyltransferase (DGAT1) gene on milk production traits in German Holstein cows

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    <p>Abstract</p> <p>Background</p> <p>Substantial gene substitution effects on milk production traits have formerly been reported for alleles at the K232A and the promoter VNTR loci in the bovine acylCoA-diacylglycerol-acyltransferase 1 (<it>DGAT1</it>) gene by using data sets including sires with accumulated phenotypic observations of daughters (breeding values, daughter yield deviations). However, these data sets prevented analyses with respect to dominance or parent-of-origin effects, although an increasing number of reports in the literature outlined the relevance of non-additive gene effects on quantitative traits.</p> <p>Results</p> <p>Based on a data set comprising German Holstein cows with direct trait measurements, we first confirmed the previously reported association of <it>DGAT1 </it>promoter VNTR alleles with milk production traits. We detected a dominant mode of effects for the <it>DGAT1 </it>K232A and promoter VNTR alleles. Namely, the contrasts between the effects of heterozygous individuals at the <it>DGAT1 </it>loci differed significantly from the midpoint between the effects for the two homozygous genotypes for several milk production traits, thus indicating the presence of dominance. Furthermore, we identified differences in the magnitude of effects between paternally and maternally inherited <it>DGAT1 </it>promoter VNTR – K232A haplotypes indicating parent-of-origin effects on milk production traits.</p> <p>Conclusion</p> <p>Non-additive effects like those identified at the bovine <it>DGAT1 </it>locus have to be accounted for in more specific QTL detection models as well as in marker assisted selection schemes. The <it>DGAT1 </it>alleles in cattle will be a useful model for further investigations on the biological background of non-additive effects in mammals due to the magnitude and consistency of their effects on milk production traits.</p

    International cohort study indicates no association between alpha-1 blockers and susceptibility to COVID-19 in benign prostatic hyperplasia patients

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    Purpose: Alpha-1 blockers, often used to treat benign prostatic hyperplasia (BPH), have been hypothesized to prevent COVID-19 complications by minimising cytokine storm release. The proposed treatment based on this hypothesis currently lacks support from reliable real-world evidence, however. We leverage an international network of large-scale healthcare databases to generate comprehensive evidence in a transparent and reproducible manner.Methods: In this international cohort study, we deployed electronic health records from Spain (SIDIAP) and the United States (Department of Veterans Affairs, Columbia University Irving Medical Center, IQVIA OpenClaims, Optum DOD, Optum EHR). We assessed association between alpha-1 blocker use and risks of three COVID-19 outcomes-diagnosis, hospitalization, and hospitalization requiring intensive services-using a prevalent-user active-comparator design. We estimated hazard ratios using state-of-the-art techniques to minimize potential confounding, including large-scale propensity score matching/stratification and negative control calibration. We pooled database-specific estimates through random effects meta-analysis.Results: Our study overall included 2.6 and 0.46 million users of alpha-1 blockers and of alternative BPH medications. We observed no significant difference in their risks for any of the COVID-19 outcomes, with our meta-analytic HR estimates being 1.02 (95% CI: 0.92-1.13) for diagnosis, 1.00 (95% CI: 0.89-1.13) for hospitalization, and 1.15 (95% CI: 0.71-1.88) for hospitalization requiring intensive services.Conclusion: We found no evidence of the hypothesized reduction in risks of the COVID-19 outcomes from the prevalent-use of alpha-1 blockers-further research is needed to identify effective therapies for this novel disease.</p
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