345 research outputs found
Quantum theta functions and Gabor frames for modulation spaces
Representations of the celebrated Heisenberg commutation relations in quantum
mechanics and their exponentiated versions form the starting point for a number
of basic constructions, both in mathematics and mathematical physics (geometric
quantization, quantum tori, classical and quantum theta functions) and signal
analysis (Gabor analysis).
In this paper we try to bridge the two communities, represented by the two
co--authors: that of noncommutative geometry and that of signal analysis. After
providing a brief comparative dictionary of the two languages, we will show
e.g. that the Janssen representation of Gabor frames with generalized Gaussians
as Gabor atoms yields in a natural way quantum theta functions, and that the
Rieffel scalar product and associativity relations underlie both the functional
equations for quantum thetas and the Fundamental Identity of Gabor analysis.Comment: 38 pages, typos corrected, MSC class change
Correction: The Effects of Melatonin Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
his systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to clarify the effect of melatonin supplementation on glycemic control. Databases including PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were searched until July 30th, 2018. Two reviewers independently assessed study eligibility, extracted data, and evaluated the risk of bias for included trials. Heterogeneity among included studies was assessed using Cochran’s Q test and I-square (I2) statistic. Data were pooled using random-effect models and mean difference (MD) was considered as the overall effect size. Twelve trials out of 292 selected reports were identified eligible to be included in current meta-analysis. The pooled findings indicated that melatonin supplementation significantly reduced fasting glucose (MD=–6.34; 95% CI, –12.28, –0.40; p=0.04; I2: 65.0) and increased the quantitative insulin sensitivity check index (QUICKI) (MD=0.01; 95% CI, 0.00, 0.02; p=0.01; I2: 0.0). However, melatonin administration did not significantly influence insulin levels (MD=–1.03; 95% CI, –3.82, 1.77; p=0.47; I2: 0.53), homeostasis model assessment of insulin resistance (HOMA-IR) (MD=–0.34; 95% CI, –1.25, 0.58; p=0.37; I2: 0.37) or HbA1c levels (MD=–0.22; 95% CI, –0.47, 0.03; p=0.08; I2: 0.0). In summary, the current meta-analysis showed a promising effect of melatonin supplementation on glycemic control through reducing fasting glucose and increasing QUICKI, yet additional prospective studies are recommended, using higher supplementation doses and longer intervention period, to confirm the impact of melatonin on insulin levels, HOMA-IR and HbA1c.
Key words:
melatonin - glycemic control - insulin resistance - meta-analysi
Potential benefits of melatonin in organ transplantation: a review
Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acid L-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation
Erratum: Correction: The Effects of Melatonin Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme (2018) 50 11 (783-790))
In the article, the name of the co-author was given incorrectly. The correct name of the author is Mohammad Ali Mansournia. In the abstract section the correct abbreviation of �mean difference� is MD. © Georg Thieme Verlag KG Stuttgart · New York
The Effects of Melatonin Supplementation on Parameters of Mental Health, Glycemic Control, Markers of Cardiometabolic Risk, and Oxidative Stress in Diabetic Hemodialysis Patients: A Randomized, Double-Blind, Placebo-Controlled Trial
Objective: This study evaluated the effects of melatonin supplementation on parameters of mental health, glycemic control, markers of cardiometabolic risk, and oxidative stress in diabetic hemodialysis (HD) patients. Design: A randomized, double-blind, placebo-controlled clinical trial was conducted in 60 diabetic HD patients, 18-80 years of age. Participants were randomly divided into 2 groups to take either melatonin (2 x 5mg/day) (n = 30) or placebo (n = 30) 1 hour before bedtime for 12 weeks. The effects of melatonin on mental health, metabolic status, and gene expression related to metabolic status were assessed using multiple linear regression adjusting for age and BMI. Results: Melatonin supplementation significantly decreased Pittsburgh Sleep Quality Index (P =.007), Beck Depression Inventory index (P =.001), and Beck Anxiety Inventory index (P =.01) compared with the placebo. Additionally, melatonin administration significantly reduced fasting plasma glucose (β = �21.77 mg/dL, 95 CI �33.22 to �10.33, P <.001), serum insulin levels (β = �1.89 μIU/mL, 95 CI �3.34 to �0.45, P =.01), and homeostasis model of assessment-insulin resistance (β = �1.45, 95 CI �2.10 to �0.80, P <.001), and significantly increased the quantitative insulin sensitivity check index (β = 0.01, 95 CI 0.007-0.02, P <.001) compared with placebo treated subjects. In addition, melatonin administration resulted in a significant reduction in serum high sensitivity C-reactive protein (β = �1.92 mg/L, 95 CI �3.02 to �0.83, P =.001) and plasma malondialdehyde (β = �0.21 μmol/L, 95 CI �0.36 to �0.06, P =.005); also, significant rises in plasma total antioxidant capacity (β = 253.87 mmol/L, 95 CI 189.18-318.56, P <.001) and nitric oxide levels (β = 2.99 μmol/L, 95 CI 0.71-5.28, P =.01) were observed compared with the placebo. Conclusion: Overall, melatonin supplementation for 12 weeks to diabetic HD patients had beneficial effects on mental health, glycemic control, inflammatory markers, and oxidative stress. © 2019 National Kidney Foundation, Inc
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
A global experience-sampling method study of well-being during times of crisis : The CoCo project
We present a global experience-sampling method (ESM) study aimed at describing, predicting, and understanding individual differences in well-being during times of crisis such as the COVID-19 pandemic. This international ESM study is a collaborative effort of over 60 interdisciplinary researchers from around the world in the “Coping with Corona” (CoCo) project. The study comprises trait-, state-, and daily-level data of 7490 participants from over 20 countries (total ESM measurements = 207,263; total daily measurements = 73,295) collected between October 2021 and August 2022. We provide a brief overview of the theoretical background and aims of the study, present the applied methods (including a description of the study design, data collection procedures, data cleaning, and final sample), and discuss exemplary research questions to which these data can be applied. We end by inviting collaborations on the CoCo dataset
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