9,303 research outputs found
Rebuttal to Hasty and Vijg: âAccelerating aging by mouse reverse genetics: a rational approach to understanding longevityâ
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72056/1/j.1474-9728.2004.00084.x.pd
General Gauge Mediation with Gauge Messengers
We generalize the General Gauge Mediation formalism to allow for the
possibility of gauge messengers. Gauge messengers occur when charged matter
fields of the susy-breaking sector have non-zero F-terms, which leads to
tree-level, susy-breaking mass splittings in the gauge fields. A classic
example is that SU(5) / SU(3) x SU(2) x U(1) gauge fields could be gauge
messengers. We give a completely general, model independent, current-algebra
based analysis of gauge messenger mediation of susy-breaking to the visible
sector. Characteristic aspects of gauge messengers include enhanced
contributions to gaugino masses, (tachyonic) sfermion mass-squareds generated
already at one loop, and also at two loops, and significant one-loop A-terms,
already at the messenger scale.Comment: 79 pages, 5 figure
HYPERPHOSPHATEMIA IN END STAGE RENAL DISEASE: PREVALENCE AND PATIENTS CHARACTERISTICS OF MULTIETHNIC POPULATION OF UNITED ARAB EMIRATES
Objective: Hyperphosphatemia is significantly associated with increased mortality among end stage renal disease (ESRD) patients on hemodialysis. There is paucity of data on hyperphosphatemia in ESRD patients of the multiethnic population of United Arab Emirates (UAE). The study aimed to investigate the prevalence and characteristics of hyperphosphatemia in ESRD patients of the multiethnic population of UAE undergoing maintenance hemodialysis.Methods: Adults ESRD patients undergoing maintenance hemodialysis for more than six months at the study site were included. Demographic, clinical and biological data of the patients were collected. Patient characteristics were compared as per the serum phosphate level, between patients with or without hyperphosphatemia. Univariate and multivariate logistic regression analyses were carried out to identify the predictors of hyperphosphatemia.Results: Hyperphosphatemia was present in 73.8% of the study population, while 31.3% presented with high calcium-phosphate product. Univariate logistic analysis revealed that hyperphosphatemia was inversely correlated with age, hemoglobin, serum calcium, and hypertensive nephropathy as cause of renal disease, and positively correlated with female gender, expatriate status, body mass index (BMI), higher number of comorbidities, calcium-phosphate product and parathyroid hormone (PTH). Multivariate logistic regression model revealed that only age, BMI, hemoglobin and PTH independently correlated with hyperphosphatemia.Conclusion: We report a high prevalence of hyperphosphatemia in multiethnic study population undergoing maintenance hemodialysis at a secondary care hospital in UAE. In this study population, only age, BMI, hemoglobin and PTH were identified as independent predictors of hyperphosphatemia
Cross-sectional evaluation of a longitudinal consultation skills course at a new UK medical school
Background: Good communication is a crucial element of good clinical care, and it is important to provide appropriate consultation skills teaching in undergraduate medical training to ensure that doctors have the necessary skills to communicate effectively with patients and other key stakeholders. This article aims to provide research evidence of the acceptability of a longitudinal consultation skills strand in an undergraduate medical course, as assessed by a cross-sectional evaluation of students' perceptions of their teaching and learning experiences. Methods: A structured questionnaire was used to collect student views. The questionnaire comprised two parts: 16 closed questions to evaluate content and process of teaching and 5 open-ended questions. Questionnaires were completed at the end of each consultation skills session across all year groups during the 2006-7 academic year (5 sessions in Year 1, 3 in Year 2, 3 in Year 3, 10 in Year 4 and 10 in Year 5). 2519 questionnaires were returned in total. Results: Students rated Tutor Facilitation most favourably, followed by Teaching, then Practice & Feedback, with suitability of the Rooms being most poorly rated. All years listed the following as important aspects they had learnt during the session: âą how to structure the consultation âą importance of patient-centredness âą aspects of professionalism (including recognising own limits, being prepared, generally acting professionally). All years also noted that the sessions had increased their confidence, particularly through practice. Conclusions: Our results suggest that a longitudinal and integrated approach to teaching consultation skills using a well structured model such as Calgary-Cambridge, facilitates and consolidates learning of desired process skills, increases student confidence, encourages integration of process and content, and reinforces appreciation of patient-centredness and professionalism
Cytogerontology since 1881: A reappraisal of August Weismann and a review of modern progress
Cytogerontology, the science of cellular ageing, originated in 1881 with the prediction by August Weismann that the somatic cells of higher animals have limited division potential. Weismann's prediction was derived by considering the role of natural selection in regulating the duration of an organism's life. For various reasons, Weismann's ideas on ageing fell into neglect following his death in 1914, and cytogerontology has only reappeared as a major research area following the demonstration by Hayflick and Moorhead in the early 1960s that diploid human fibroblasts are restricted to a finite number of divisions in vitro.
In this review we give a detailed account of Weismann's theory, and we reveal that his ideas were both more extensive in their scope and more pertinent to current research than is generally recognised. We also appraise the progress which has been made over the past hundred years in investigating the causes of ageing, with particular emphasis being given to (i) the evolution of ageing, and (ii) ageing at the cellular level. We critically assess the current state of knowledge in these areas and recommend a series of points as primary targets for future research
Enlarging the tools for efficient enzymatic polycondensation: structural and catalytic features of cutinase 1 from Thermobifida cellulosilytica
9siCutinase 1 from Thermobifida cellulosilytica is reported for the first time as an efficient biocatalyst in polycondensation reactions. Under thin film conditions the covalently immobilized enzyme catalyzes the synthesis of oligoesters of dimetil adipate with different polyols leading to higher Mw (~1900) and Mn (~1000) if compared to lipase B from Candida antarctica or cutinase from Humicola insolens. Computational analysis discloses the structural features that make this enzyme readily accessible to substrates and optimally suited for covalent immobilization. As lipases and other cutinase enzymes, it presents hydrophobic superficial regions around the active site. However, molecular dynamics simulations indicate the absence of interfacial activation, similarly to what already documented for lipase B from Candida antarctica. Notably, cutinase from Humicola insolens displays a âbreathing likeâ conformational movement, which modifies the accessibility of the active site. These observations stimulate wider experimental and bioinformatics studies aiming at a systematic comparison of functional differences between cutinases and lipases.partially_openembargoed_20161210Pellis, Alessandro; Ferrario, Valerio; Zartl, Barbara; Brandauer, Martin; Gamerith, Caroline; Herrero-Acero, Enrique; Ebert, Cynthia; Gardossi, Lucia; Guebitz, GeorgPellis, Alessandro; Ferrario, Valerio; Zartl, Barbara; Brandauer, Martin; Gamerith, Caroline; Herrero Acero, Enrique; Ebert, Cynthia; Gardossi, Lucia; Guebitz, Geor
Genetic and Environmental Influences on Individual Differences in Attitudes Toward Homosexuality: An Australian Twin Study
Previous research has shown that many heterosexuals hold negative attitudes toward homosexuals and homosexuality (homophobia). Although a great deal of research has focused on the profile of homophobic individuals, this research provides little theoretical insight into the aetiology of homophobia. To examine genetic and environmental influences on variation in attitudes toward homophobia, we analysed data from 4,688 twins who completed a questionnaire concerning sexual behaviour and attitudes, including attitudes toward homosexuality. Results show that, in accordance with literature, males have significantly more negative attitudes toward homosexuality than females and non-heterosexuals are less homophobic than heterosexuals. In contrast with some earlier findings, age had no significant effect on the homophobia scores in this study. Genetic modelling showed that variation in homophobia scores could be explained by additive genetic (36%), shared environmental (18%) and unique environmental factors (46%). However, corrections based on previous findings show that the shared environmental estimate may be almost entirely accounted for as extra additive genetic variance arising from assortative mating for homophobic attitudes. The results suggest that variation in attitudes toward homosexuality is substantially inherited, and that social environmental influences are relatively minor
The impact of temperature on wave interaction with damage in composite structures
The increased use of composite materials in modern aerospace and automotive structures, and the broad range of launch vehiclesâ operating temperature imply a great temperature range for which the structures has to be frequently and thoroughly inspected. A thermal mechanical analysis is used to experimentally measure the temperature-dependent mechanical properties of a composite layered panel in the range of â100ââ to 150ââ. A hybrid wave finite element/finite element computational scheme is developed to calculate the temperature-dependent wave propagation and interaction properties of a system of two structural waveguides connected through a coupling joint. Calculations are made using the measured thermomechanical properties. Temperature-dependent wave propagation constants of each structural waveguide are obtained by the wave finite element approach and then coupled to the fully finite element described coupling joint, on which damage is modelled, in order to calculate the scattering magnitudes of the waves interaction with damage across the coupling joint. The significance of the panelâs glass transition range on the measured and calculated properties is emphasised. Numerical results are presented as illustration of the work
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Persistence in the realized betas: some evidence from the stock market
JEL Classification: C22; G11Data Availability Statement:
The authors declare that all data supporting the findings of this study is available within the article. In particular, the calculation datasets generated during and/or analyzed during the current study are available from the corresponding author on request. The results/data/figures in this manuscript have not been published elsewhere, nor are they under consideration by another publisher, and there are not hyperlinks to publicly archived datasets analysed or generated during the study except for the public information collected.This paper examines the stochastic behaviour of the realized betas in the CAPM model for the ten largest companies in terms of market capitalisation included in the U.S. Dow Jones stock market index. Fractional integration methods are applied to estimate their degree of persistence at daily, weekly, and monthly frequencies over the period July 2000âJuly 2020 over time spans of 1, 3, and 5 years. On the whole, the results indicate that the realized betas are highly persistent and do not exhibit weak mean-reverting behaviour at the weekly and daily frequencies, whilst there is some evidence of weak mean reversion at the monthly frequency. Our findings confirm the sensitivity of beta calculations to the choice of frequency and time span (the number of observations).Luis A. Gil-Alana and Miguel MartĂn-Valmayor gratefully acknowledges financial support from the Grant PID2020-113691RB-I00 funded by MCIN/AEI/10.13039/501100011033, from âMinisterio de Ciencia e InnovaciĂłnâ (MICIN), Agencia Estatal de InvestigaciĂłnâ (AEI) Spain and âFondo Europeo de Desarrollo Regionalâ (FEDER)
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