102 research outputs found
Magnesium but not nicotinamide prevents vascular calcification in experimental uraemia
BACKGROUND: Optimal phosphate control is an unmet need in chronic kidney disease (CKD). High serum phosphate increases calcification burden and is associated with mortality and cardiovascular disease in CKD. Nicotinamide (NA) alone or in combination with calcium-free phosphate binders might be a strategy to reduce phosphate levels and calcification and thus impact cardiovascular disease in CKD. METHODS: We studied the effect of NA alone and in combination with magnesium carbonate (MgCO3) as a potential no
Comparison of geometric morphometric outline methods in the discrimination of age-related differences in feather shape
BACKGROUND: Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. RESULTS: Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method of outline measurement. Rates of classification were not highly dependent on the number of points used to represent a curve or the manner in which those points were acquired. The new approach to dimensionality reduction, which utilizes a variable number of principal component (PC) axes, produced higher cross-validation assignment rates than either the standard approach of using a fixed number of PC axes or a partial least squares method. CONCLUSION: Classification of specimens based on feather shape was not highly dependent of the details of the method used to capture shape information. The choice of dimensionality reduction approach was more of a factor, and the cross validation rate of assignment may be optimized using the variable number of PC axes method presented herein
Reincorporating Friedrich von Wieser and the Concept of Power into the Austrian Research Program
This paper constitutes the start of a project dedicated to Austrian economist and economic sociologist Friedrich von Wieser (1851-1926). Its central claim is that especially in recent decades, Wieser has become a disproportionately underresearched scholar, and the paper provides a set of arguments why this is unjustified. Wieser's life and work are portrayed along five dimensions: the innovative social scientist (section 2); the erector of the Austrian School in its formative decades (section 3); the synthesizer of socio-economic ideas (section 4); the teacher to whom scientific credit has been granted undeservedly seldom (section 5); finally, the connector to other contemporaneous paradigms of economics and economic sociology, especially the ones of Max Weber and Vilfredo Pareto (section 6). The paper sets up a meta-presentation of a set of questions that appear crucial at this stage of the project. In subsequent sub-projects, the five above dimensions will be expanded into separate but interdependent expositions. As an example for the initiation of such a sub-project, Wieser's concept of power - a key topos also for the other members of the Viennese "triumvirate" - is revisited (section 7). Since later generations of the Austrian School have been reluctant to use this concept in their systems, this and later inquiries will explore how central Austrian concepts like "spontaneous order" or "human action" may need a reformulation if power relations are explicitly built into the analysis. While the project is primarily conducted as a history of economics endeavor, revisiting Wieser's legacy in general and the significance of power in particular also aims at generating impulses for the further development of the research program of Austrian economics, as well as at a better understanding of the increasing politico-economic fragility and instability of today's Western democracies, phenomena related to power and leadership
Die Rolle von Natriumionen bei der Kopplung von endergonen und exergonen Reaktionen der Methanbildung aus CO_2 und H_2
Available from the library of Marburg Univ. (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
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Predicting Overprecision in Range Estimation
Overprecision (overconfidence in interval estimation) is a biaswith clear implications for economic outcomes in industriesreliant on forecasting possible ranges for future prices andunknown states of nature - such as mineral and petroleumexploration. Prior research has shown the ranges peopleprovide are too narrow given the knowledge they have – thatis, they underestimate uncertainty and are overconfident intheir knowledge. The underlying causes of this bias are,however, still unclear and individual differences research hasshed little light on traits predictive of susceptibility. Takingthis as a starting point, this paper directly contrasts the NaïveSampling Model and Informativeness-Accuracy Tradeoffaccounts of overprecision – seeing which better predictsperformance in an interval estimation task. This was achievedby identifying traits associated with these theories – ShortTerm Memory and Need for Cognitive Closure, respectively.Analyses indicate that NFCC but not STM predicts intervalwidth and thus, potentially, impacts overprecision
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