45 research outputs found
Study protocol; Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism - a randomised placebo controlled Trial (TRUST).
Subclinical hypothyroidism (SCH) is a common condition in elderly people, defined as elevated serum thyroid-stimulating hormone (TSH) with normal circulating free thyroxine (fT4). Evidence is lacking about the effect of thyroid hormone treatment. We describe the protocol of a large randomised controlled trial (RCT) of Levothyroxine treatment for SCH.
Participants are community-dwelling subjects aged â„65 years with SCH, diagnosed by elevated TSH levels (â„4.6 and â€19.9 mU/L) on a minimum of two measuresââ„âthree months apart, with fT4 levels within laboratory reference range. The study is a randomised double-blind placebo-controlled parallel group trial, starting with levothyroxine 50 micrograms daily (25 micrograms in subjects <50Kg body weight or known coronary heart disease) with titration of dose in the active treatment group according to TSH level, and a mock titration in the placebo group. The primary outcomes are changes in two domains (hypothyroid symptoms and fatigue / vitality) on the thyroid-related quality of life questionnaire (ThyPRO) at one year. The study has 80% power (at pâ=â0.025, 2-tailed) to detect a change with levothyroxine treatment of 3.0% on the hypothyroid scale and 4.1% on the fatigue / vitality scale with a total target sample size of 750 patients. Secondary outcomes include general health-related quality of life (EuroQol), fatal and non-fatal cardiovascular events, handgrip strength, executive cognitive function (Letter Digit Coding Test), basic and instrumental activities of daily living, haemoglobin, blood pressure, weight, body mass index and waist circumference. Patients are monitored for specific adverse events of interest including incident atrial fibrillation, heart failure and bone fracture.
This large multicentre RCT of levothyroxine treatment of subclinical hypothyroidism is powered to detect clinically relevant change in symptoms / quality of life and is likely to be highly influential in guiding treatment of this common condition.
Clinicaltrials.gov NCT01660126 ; registered 8th June 2012
First direct measurement of 12C (12C,n) 23Mg at stellar energies
© 2016 Owned by the authors, published by EDP Sciences. Neutrons produced by the carbon fusion reaction12C(12C,n)23Mg play an important role in stellar nucleosynthesis. Past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement which extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction12C(12C,p)23Na. The new reaction rate has been determined with a well-defined uncertainty which exceeds the precision required by astrophysics models. Using our constrained rate, we find that12C(12C,n)23Mg is crucial to the production of Na and Al in Pop-III Pair Instability Supernovae
Constraining the 12C+12C fusion cross section for astrophysics
The 12 C+ 12 C reaction is one of the single most important nuclear reactions in astrophysics. It strongly influences late evolution of massive stars as well as the dynamics of type Ia supernovae and x-ray superbursts. An accurate estimation of the cross section at relevant astrophysical energies is extremely important for modeling these systems. However, the situation is complicated by the unpredictable resonance structure observed at higher energies. Two recent studies at Notre Dame have produced results which help reduce the uncertainty associated with this reaction. The first uses correlations with the isotope fusion systems, 12 C+ 13 C and 13 C+ 13 C, to establish an upper limit on the resonance strengths in 12 C+ 12 C. The other focuses on the specific channel 12 C+ 12 Câ 23 Mg+n and its low-energy measurement and extrapolation which is relevant to s-process nucleosynthesis. The results from each provide important constraints for astrophysical models
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Similarities and differences in the historical records of lava dome-building volcanoes: implications for understanding magmatic processes and eruption forecasting
A key question for volcanic hazard assessment is the extent to which information can be exchanged between volcanoes. This question is particularly pertinent to hazard forecasting for dome-building volcanoes, where effusive activity may persist for years to decades, and may be punctuated by periods of repose, and sudden explosive activity. Here we review historical eruptive activity of fifteen lava dome-building volcanoes over the past two centuries, with the goal of creating a hierarchy of exchangeable (i.e., similar) behaviours. Eruptive behaviour is classified using empirical observations that include patterns of SO2 flux, eruption style, and magma composition. We identify two eruptive regimes: (i) an episodic regime where eruptions are much shorter than intervening periods of repose, and degassing is temporally correlated with lava effusion; and (ii) a persistent regime where eruptions are comparable in length to periods of repose and gas emissions do not correlate with eruption rates. A corollary to these two eruptive regimes is that there are also two different types of repose: (i) inter-eruptive repose separates episodic eruptions, and is characterised by negligible gas emissions and (ii) intra-eruptive repose is observed in persistently active volcanoes, and is characterised by continuous gas emissions. We suggest that these different patterns of can be used to infer vertical connectivity within mush-dominated magmatic systems. We also note that our recognition of two different types of repose raises questions about traditional definitions of historical volcanism as a point process. This is important, because the ontology of eruptive activity (that is, the definition of volcanic activity in time) influences both analysis of volcanic data and, by extension, interpretations of magmatic processes. Our analysis suggests that one identifying exchangeable traits or behaviours provides a starting point for developing robust ontologies of volcanic activity. Moreover, by linking eruptive regimes to conceptual models of magmatic processes, we illustrate a path towards developing a conceptual framework not only for comparing data between different volcanoes but also for improving forecasts of eruptive activity
Necessary Conditions for Mean Square Convergence of the Best Linear Factor Predictor
Heywood cases, constrained factor analysis, factor indeterminacy, common factor analysis, confirmatory factor analysis, true factor scores,
STATE LEGISLATORS AND ECONOMIC DEVELOPMENT: UNIVERSITY-INDUSTRY RELATIONSHIPS AND THE ROLE OF GOVERNMENT IN BIOTECHNOLOGY
This article presents a detailed examination of some key political dimen- sions underlying cooperative research in agricultural biotechnology among state land-grant universities, state legislatures, and biotechnology corpora- tions. Factor analysis and path analysis methods are employed to assess differences in the perceptions of university administrators, biotechnology corporation researchers, and state legislators, using national and state survey data. Two attitudinal dimensions, one regarding cooperation among university and corporate researchers, and the other regarding barriers to joint research, are extracted. Generally similar attitudes are shared by university and legislative respondents, who are concerned over the prospects of market-oriented university research. In contrast, corporate respondents are more concerned with reducing barriers to cooperative research and the need for more open communication between academia and industry, and with issues of patent rights. Extensions of this work to other states and to other high-technology industries are considered. Copyright 1990 by The Policy Studies Organization.
Farmers and the U.S. Congress: rethinking basic institutional assumptions about agricultural policy
The Hungry Mind : Intellectual Curiosity Is the Third Pillar of Academic Performance
Over the past century, academic performance has become the gatekeeper to institutions of higher education, shaping career paths and individual life trajectories. Accordingly, much psychological research has focused on identifying predictors of academic performance, with intelligence and effort emerging as core determinants. In this article, we propose expanding on the traditional
set of predictors by adding a third agency: intellectual curiosity. A series of path models based on a meta-analytically derived correlation matrix showed that (a) intelligence is the single most powerful predictor of academic performance; (b) the effects of intelligence on academic performance are not mediated by personality traits; (c) intelligence, Conscientiousness (as marker
of effort), and Typical Intellectual Engagement (as marker of intellectual curiosity) are direct, correlated predictors of academic performance; and (d) the additive predictive effect of the personality traits of intellectual curiosity and effort rival that the influence of intelligence. Our results highlight that a âhungry mindâ is a core determinant of individual differences in academic
achievement