5,077 research outputs found
Supersymmetric Distributions, Hilbert Spaces of Supersymmetric Functions and Quantum Fields
The recently investigated Hilbert-Krein and other positivity structures of
the superspace are considered in the framework of superdistributions. These
tools are applied to problems raised by the rigorous supersymmetric quantum
field theory.Comment: 24 page
Van der Waerden calculus with commuting spinor variables and the Hilbert-Krein structure of the superspace
Working with anticommuting Weyl(or Mayorana) spinors in the framework of the
van der Waerden calculus is standard in supersymmetry. The natural frame for
rigorous supersymmetric quantum field theory makes use of operator-valued
superdistributions defined on supersymmetric test functions. In turn this makes
necessary a van der Waerden calculus in which the Grassmann variables
anticommute but the fermionic components are commutative instead of being
anticommutative. We work out such a calculus in view of applications to the
rigorous conceptual problems of the N=1 supersymmetric quantum field theory.Comment: 14 page
Body Contouring Surgery Following Bariatric Surgery and Dietetically Induced Massive Weight Reduction: A Risk Analysis
Background: This study analyzed the impact of weight reduction method, preoperative, and intraoperative variables on the outcome of reconstructive body contouring surgery following massive weight reduction. Methods: All patients presenting with a maximal BMI ≥35kg/m2 before weight reduction who underwent body contouring surgery of the trunk following massive weight loss (excess body mass index loss (EBMIL) ≥ 30%) between January 2002 and June 2007 were retrospectively analyzed. Incomplete records or follow-up led to exclusion. Statistical analysis focused on weight reduction method and pre-, intra-, and postoperative risk factors. The outcome was compared to current literature results. Results: A total of 104 patients were included (87 female and 17 male; mean age 47.9years). Massive weight reduction was achieved through bariatric surgery in 62 patients (59.6%) and dietetically in 42 patients (40.4%). Dietetically achieved excess body mass index loss (EBMIL) was 94.20% and in this cohort higher than surgically induced reduction EBMIL 80.80% (p < 0.01). Bariatric surgery did not present increased risks for complications for the secondary body contouring procedures. The observed complications (26.9%) were analyzed for risk factors. Total tissue resection weight was a significant risk factor (p < 0.05). Preoperative BMI had an impact on infections (p < 0.05). No impact on the postoperative outcome was detected in EBMIL, maximal BMI, smoking, hemoglobin, blood loss, body contouring technique or operation time. Corrective procedures were performed in 11 patients (10.6%). The results were compared to recent data. Conclusion: Bariatric surgery does not increase risks for complications in subsequent body contouring procedures when compared to massive dietetic weight reductio
The effect of population variation on the accuracy of sex estimates derived from basal occipital discriminant functions
Multiple discriminant functions that estimate sex from the dimensions of the basal occipital have been published. However, as there is limited exploration of basal dimension variation between groups, the accuracy of these functions when applied to archaeological material is unknown. This study compares basal dimensions between four known sex-at-death post-medieval European samples and explores how metric differences impact on the accuracy of sex assessment discriminant functions. Published data from St Bride’s, London (n = 146) and the Georges Olivier collection, Paris (n = 68) were compared with new data from the eighteenth to nineteenth century Dutch Middenbeemster sample (n = 74) and the early twentieth century Rainer sample, Romania (n = 282) using independent t tests. The Middenbeemster and Rainer data were substituted into six published discriminant functions derived from the St Bride’s and the Georges Olivier samples, and the results were compared to their known sex. Multiple statistically significant differences were found between the four groups. Of the six discriminant functions tested, five failed to reach the published accuracy and fell below chance. In addition, even where the samples were statistically comparable in means, trends for difference also impacted the accuracy of discriminant functions. Enough variation in basal occipital dimensions existed in the European groups to decrease the accuracy of sex estimation discriminant functions to unusable. Possible inter-observer error, varying genetic, socioeconomic, and geographical factors are likely causes of dimension variation. This research further highlights the dangers of using sex estimation discriminant functions on samples that differ to the original derivative population and demonstrates the need for more rigorous testing
Role of oral teriflunomide in the management of multiple sclerosis
The landscape of the treatment of relapsing–remitting multiple sclerosis is changing fast. Several oral treatments have shown benefit and generate much interest because of the convenience of their administration. Two oral compounds, fingolimod and teriflunomide, have been approved in relapsing–remitting multiple sclerosis, while others have completed Phase III trials and are awaiting review for registration. Teriflunomide is a pyrimidine synthesis inhibitor with selective immunomodulatory and immunosuppressive properties that have shown consistent efficacy in clinical trials, and a good safety profile. This paper provides an overview of the mechanisms of action and efficacy and safety results from clinical trials with this drug. The role of teriflunomide in the treatment of relapsing–remitting multiple sclerosis is discussed
In-flight calibration of the Hot Ion Analyser on board Cluster
The Hot Ion Analyser (HIA), part of the Cluster Ion Spectrometry experiment,
has the objective to measure the three-dimensional velocity distributions of
ions. Due to a variety of factors (exposure to radiation, detector fatigue
and aging, changes in the operating parameters, etc.), the particles' detection
efficiency changes over time, prompting for continuous in-flight calibration.
This is achieved by comparing the HIA data with the data provided by the
WHISPER (Waves of HIgh frequency and Sounder for Probing of Electron
density by Relaxation) experiment on magnetosheath intervals, for the high-sensitivity
section of the instrument, or solar wind intervals, for the low-sensitivity
section. The paper presents in detail the in-flight calibration methodology,
reports on the work carried out for calibrating HIA and discusses plans to
extend this activity in order to ensure the instrument's highest data accuracy
Supersymmetric Field-Theoretic Models on a Supermanifold
We propose the extension of some structural aspects that have successfully
been applied in the development of the theory of quantum fields propagating on
a general spacetime manifold so as to include superfield models on a
supermanifold. We only deal with the limited class of supermanifolds which
admit the existence of a smooth body manifold structure. Our considerations are
based on the Catenacci-Reina-Teofillatto-Bryant approach to supermanifolds. In
particular, we show that the class of supermanifolds constructed by
Bonora-Pasti-Tonin satisfies the criterions which guarantee that a
supermanifold admits a Hausdorff body manifold. This construction is the
closest to the physicist's intuitive view of superspace as a manifold with some
anticommuting coordinates, where the odd sector is topologically trivial. The
paper also contains a new construction of superdistributions and useful results
on the wavefront set of such objects. Moreover, a generalization of the
spectral condition is formulated using the notion of the wavefront set of
superdistributions, which is equivalent to the requirement that all of the
component fields satisfy, on the body manifold, a microlocal spectral condition
proposed by Brunetti-Fredenhagen-K\"ohler.Comment: Final version to appear in J.Math.Phy
Coordinate based random effect size meta-analysis of neuroimaging studies
Low power in neuroimaging studies can make them difficult to interpret, and Coordinate based meta-analysis (CBMA) may go some way to mitigating this issue. CBMA has been used in many analyses to detect where published functional MRI or voxel-based morphometry studies testing similar hypotheses report significant summary results (coordinates) consistently. Only the reported coordinates and possibly t statistics are analysed, and statistical significance of clusters is determined by coordinate density.
Here a method of performing coordinate based random effect size meta-analysis and meta-regression is introduced. The algorithm (ClusterZ) analyses both coordinates and reported t statistic or Z score, standardised by the number of subjects. Statistical significance is determined not by coordinate density, but by a random effects meta-analyses of reported effects performed cluster-wise using standard statistical methods and taking account of censoring inherent in the published summary results. Type 1 error control is achieved using the false cluster discovery rate (FCDR), which is based on the false discovery rate. This controls both the family wise error rate under the null hypothesis that coordinates are randomly drawn from a standard stereotaxic space, and the proportion of significant clusters that are expected under the null. Such control is necessary to avoid propagating and even amplifying the very issues motivating the meta-analysis in the first place. ClusterZ is demonstrated on both numerically simulated data and on real data from reports of grey matter loss in multiple sclerosis (MS) and syndromes suggestive of MS, and of painful stimulus in healthy controls. The software implementation is available to download and use freely
Dispersive calculation of the massless multi-loop sunrise diagram
The massless sunrise diagram with an arbitrary number of loops is calculated
in a simple but formal manner. The result is then verified by rigorous
mathematical treatment. Pitfalls in the calculation with distributions are
highlighted and explained. The result displays the high energy behaviour of the
massive sunrise diagrams, whose calculation is involved already for the
two-loop case.Comment: 10 pages, 1 figure, LATEX, uses kluwer.cls, some references adde
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