423 research outputs found
Numerical and asymptotic solutions of generalised Burgersâ equation
The generalised Burgersâ equation has been subject to a considerable amount of research on how the equation should behave according to asymptotic analysis, however there has been limited research verifying the asymptotic analysis. In order to verify the asymptotic analysis, this paper aims to run long time and detailed numerical simulations of Burgersâ equation by employing suitable rescalings of Burgersâ equation. It is hoped that this technique will make it possible to notice subtle changes in the shock structure which would otherwise be impossible to observe. The main aim of this paper is to validate the numerical methods used in order to allow further research into shock evolution where further relaxation effects will be included
Corporate social responsibility and financial performance: A non-linear and disaggregated approach
The present paper examines the relationship between Corporate Social Performance (CSP) and Corporate Financial Performance (CFP), using both accounting-based (Return on Assets and Return on Capital) and market-based (Excess Stock Returns) performance indicators. We use Bloomberg's Environmental Social Governance (ESG) Disclosure score covering the S&P500 firms in the period 2007â2011 which allows for the examination of both linear and nonlinear relationships to be considered. The results of the linear model suggest that there is a significant negative relationship between CSP and Return on Capital. However, the non linear models provide evidence of a U-shaped relationship between CSP and the accounting-based measures of CFP, suggesting that in the longer run CSP effects are positive. Most prominent among our results is that fact that by disentangling the ESG Disclosure score into its environmental, social and governance sub-components, we find that a U-shaped relationship exists only between the governance sub-component and CFP. A straightforward implication of our findings suggests that in order for CSR to serve the interests of the shareholders, a long-run planning and considerable resources should be dedicated at this direction, given that CSR expenditure pays off only after a threshold of CSP has been reached. Furthermore, the fact that governance is the key driver affecting the CSP-CFP relationship suggests that CSR investments should be directed to this component
Effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions: A scoping review
Background In the field of orthotics, the use of three-dimensional (3D) technology as an alternative to the conventional production process of orthoses is growing. Purpose This scoping review aimed to systematically map and summarize studies assessing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions, and to identify knowledge gaps. Methods The Cochrane Library, PubMed, EMBASE, CINAHL, Web of Science, IEEE, and PEDro were searched for studies of any type of 3D-printed orthoses for traumatic and chronic hand conditions. Any outcome related to the effectiveness of 3D-printed orthoses was considered. Two reviewers selected eligible studies, charted data on study characteristics by impairment type, and critically appraised the studies, except for case reports/series. Results Seventeen studies were included: Four randomized controlled trials, four uncontrolled trials, four case series and five case reports. Only three studies had a sample size >20. Impairments described were forearm fractures (n = 5), spasticity (n = 5), muscle weakness (n = 4), joint contractures (n = 2) and pain (n = 1). Four poor to fair quality studies on forearm fractures supported the effectiveness of 3D-printed orthoses on hand function, functionality, and satisfaction. One good quality study on spasticity demonstrated the effectiveness of 3D-printed orthoses on hand function. One poor quality pain study reported limited positive effects on satisfaction. Studies on muscle weakness and joint contractures showed no benefits. Conclusion Current literature addressing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions consists primarily of small and poor methodological quality studies. There is a need for well-designed controlled trials including patient-related outcomes, production time and cost analyses
Unraveling the Genotype-Phenotype Relationship in Hypertrophic Cardiomyopathy:Obesity-Related Cardiac Defects as a Major Disease Modifier
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is characterized by asymmetric septal thickening and diastolic dysfunction. More than 1500 mutations in genes encoding sarcomere proteins are associated with HCM. However, the genotype-phenotype relationship in HCM is incompletely understood and involves modification by additional disease hits. Recent cohort studies identify obesity as a major adverse modifier of disease penetrance, severity, and clinical course. In this review, we provide an overview of these clinical findings. Moreover, we explore putative mechanisms underlying obesity-induced sensitization and aggravation of the HCM phenotype. We hypothesize obesity-related stressors to impact on cardiomyocyte structure, metabolism, and homeostasis. These may impair cardiac function by directly acting on the primary mutation-induced myofilament defects and by independently adding to the total cardiac disease burden. Last, we address important clinical and pharmacological implications of the involvement of obesity in HCM disease modification.</p
Effect of the use of organic acids in drinking water during the last two weeks prior to slaughter on salmonella shedding
In this study we investigated the effect of adding organic acids to the drinking water of finishing pigs two weeks prior to slaughter on the shedding and prevalence rate of Salmonella at slaughter. One hundred animals from 4 Belgian pig herds infected with Salmonella were included. Fifty of these ammals received drinking water supplemented with a mixture of different organic acids during 14 days prior to slaughter. Non-treated animals served as controls. Different samples were taken: contents of ileum and rectum, mesenteric lymph nodes and carcass swabs. All samples were submitted to Salmonella isolation using standard procedures. The results could not reveal a significant difference between both groups. This may be due to the limited power of the study (only 50 animals sampled in each group) or due to the fact that the treatment duration was insufficient to prove the benefit of the used organic acids
Chemical and chemometric methods for halal authentication of gelatin: an overview
The issue of food authenticity has become a concern among religious adherents, particularly Muslims, due to the possible presence of nonhalal ingredients in foods as well as other commercial products. One of the nonhalal ingredients that commonly found in food and pharmaceutical products is gelatin which extracted from porcine source. Bovine and fish gelatin are also becoming the main commercial sources of gelatin. However, unclear information and labeling regarding the actual sources of gelatin in food and pharmaceutical products have become the main concern in halal authenticity issue since porcine consumption is prohibited for Muslims. Hence, numerous analytical methods involving chemical and chemometric analysis have been developed to identify the sources of gelatin. Chemical analysis techniques such as biochemical, chromatography, electrophoretic, and spectroscopic are usually combined with chemometric and mathematical methods such as principal component analysis, cluster, discriminant, and Fourier transform analysis for the gelatin classification. A sample result from Fourier transform infrared spectroscopy analysis, which combines Fourier transform and spectroscopic technique, is included in this paper. This paper presents an overview of chemical and chemometric methods involved in identification of different types of gelatin, which is important for halal authentication purposes
Integrating Clinical Phenotype With Multiomics Analyses of Human Cardiac Tissue Unveils Divergent Metabolic Remodeling in Genotype-Positive and Genotype-Negative Patients With Hypertrophic Cardiomyopathy
BACKGROUND: Hypertrophic cardiomyopathy (HCM) is caused by sarcomere gene mutations (genotype-positive HCM) in â50% of patients and occurs in the absence of mutations (genotype-negative HCM) in the other half of patients. We explored how alterations in the metabolomic and lipidomic landscape are involved in cardiac remodeling in both patient groups. METHODS: We performed proteomics, metabolomics, and lipidomics on myectomy samples (genotype-positive N=19; genotype-negative N=22; and genotype unknown N=6) from clinically well-phenotyped patients with HCM and on cardiac tissue samples from sex- and age-matched and body mass index-matched nonfailing donors (N=20). These data sets were integrated to comprehensively map changes in lipid-handling and energy metabolism pathways. By linking metabolomic and lipidomic data to variability in clinical data, we explored patient group-specific associations between cardiac and metabolic remodeling. RESULTS:HCM myectomy samples exhibited (1) increased glucose and glycogen metabolism, (2) downregulation of fatty acid oxidation, and (3) reduced ceramide formation and lipid storage. In genotype-negative patients, septal hypertrophy and diastolic dysfunction correlated with lowering of acylcarnitines, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines. In contrast, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines were positively associated with septal hypertrophy and diastolic impairment in genotype-positive patients. CONCLUSIONS: We provide novel insights into both general and genotype-specific metabolic changes in HCM. Distinct metabolic alterations underlie cardiac disease progression in genotype-negative and genotype-positive patients with HCM.</p
The fundamental constants and their variation: observational status and theoretical motivations
This article describes the various experimental bounds on the variation of
the fundamental constants of nature. After a discussion on the role of
fundamental constants, of their definition and link with metrology, the various
constraints on the variation of the fine structure constant, the gravitational,
weak and strong interactions couplings and the electron to proton mass ratio
are reviewed. This review aims (1) to provide the basics of each measurement,
(2) to show as clearly as possible why it constrains a given constant and (3)
to point out the underlying hypotheses. Such an investigation is of importance
to compare the different results, particularly in view of understanding the
recent claims of the detections of a variation of the fine structure constant
and of the electron to proton mass ratio in quasar absorption spectra. The
theoretical models leading to the prediction of such variation are also
reviewed, including Kaluza-Klein theories, string theories and other
alternative theories and cosmological implications of these results are
discussed. The links with the tests of general relativity are emphasized.Comment: 56 pages, l7 figures, submitted to Rev. Mod. Phy
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