Repeated failure: A source of helplessness or a factor irrelevant to its emergence?

Tested the validity of the egotism model of human helplessness (HE). In contrast to the original theoretical approach of M. E. P. Seligman (1975) and his associates, which points to response–outcome noncontingency as the main source of HE, the egotism alternative proposes that repeated failure itself is the critical determinant of HE symptoms. Repeated failure threatens the self-esteem of the S, who supposedly engages in a least-effort strategy during the test phase of a typical learned HE study, which results in performance impairment. To examine the egotism explanation, we gave Ss noncontingent-feedback training with or without repeated failure on 5 consecutive discrimination problems. In 2 experiments, noncontingent-feedback preexposure produced HE deficits in performance on avoidance learning, whereas repeated failure appeared irrelevant to HE. This and our other findings from research are inconsistent with the egotism explanation and support instead Seligman's original proposal, in which HE is attributed to prolonged experience with noncontingency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Equivalency of Lightning Return-Stroke Models Employing Lumped and Distributed Current Sources

We show that any engineering return-stroke model can be expressed, using an appropriate continuity equation, in terms of either lumped or distributed current sources with the resultant longitudinal-current distribution along the channel being the same. This property can be viewed as the duality of engineering models. The conversion alters the actual-corona current (if any) of the model. For lumped-source (LS) models the actual-corona current is unipolar and directed radially out of the channel core, while for distributed-source (DS) models it is unipolar and directed into the channel core. For LS models converted to DS models and for the Diendorfer-Uman (DU) model converted to the equivalent LS model, the corona current is the sum of the negated actual-corona current (if any) and a fictitious-corona current, the latter being bipolar. For the transmission-line (TL) model (no longitudinal current attenuation with height) expressed in terms of DSs, there is only a fictitious bipolar corona current component. Conversion of the traveling-current source (TCS) and Bruce-Golde (BG) models to equivalent LS models involves replacement of the actual, unipolar corona current with a fictitious one, the latter current being bipolar near the channel base and unipolar at higher altitudes     

A Tool for Prioritizing DAGMan Jobs and its Evaluation

It is often difficult to perform efficiently a collection of jobs with complex job dependencies due to temporal unpredictability of the Grid. One way to mitigate the unpredictability is to schedule job execution in a manner that constantly maximizes the number of jobs that can be sent to workers. A recently developed scheduling theory provides a basis to meet that optimization goal. Intuitively, when the number of such jobs is always large, high parallelism can be maintained, even if the number of workers changes over time in an unpredictable manner. In this paper we present the design, implementation, and evaluation of a practical scheduling tool inspired by the theory. Given a DAGMan input file with interdependent jobs, the tool prioritizes the jobs. The resulting schedule significantly outperforms currently used schedules under a wide range of system parameters, as shown by simulation studies. For example, a scientific data analysis application, AIRSN, was executed at least 13% faster with 95% confidence. An implementation of the tool was integrated with the Condor high-throughput computing system. The research of G. Malewicz was supported in part by NSF Grant ITR-800864. The research of I. Foster and M. Wilde was supported in part by the NSF GriPhyN project and by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38. The research of A.L. Rosenberg was supported in part by NSF Grant CCF-0342417.     

The impact of different volume fractions of crystalline structures on the electrochemical behaviour of Mg67Zn29Ca4 alloys for biomedical applications

ABSTRACT

In this work, the influence of various volume fractions of the crystalline phase in an amorphous matrix of Mg₆₇Zn₂₉Ca₄ alloys was investigated for its corrosion resistance for biodegradable applications. An amorphous Mg₆₇Zn₂₉Ca₄ alloy was successfully fabricated using melt casting into a copper mould. Then, to obtain different ratios of the crystalline phase in an amorphous matrix, the obtained amorphous rods with 3?mm diameters were annealed at 190, 230, 250, and 400°C. The volume fraction of the crystalline phase was measured by X-ray diffraction, and the microstructures of the obtained alloys were determined based on scanning electron microscopy images. Electrochemical testing was conducted in simulated body fluid at 37°C. This report shows that the ratio of the volume fractions of amorphous and crystalline phases in alloy microstructures strongly influences their corrosion behaviours. The alloy with a fully amorphous structure was the most resistive in the analysed media.     

Experimental Results on the Fixed Matrix Regenerator Effectiveness for a Glass Stove Furnace

This paper presents experimental results on the effectiveness of regenerators working integrally with an open hearth glass furnace. The presented data refer to two apparatus of identical size and geometry arranged in parallel but operating in a one-period-shifted mode. The effectiveness figures with corresponding uncertainties for each unit have been determined by making use of experimental data accounting for both heating and cooling periods. For the heating period the effectiveness is bound within the range 0.8795 ± 0.0683 to 0.9272 ± 0.0715. Considering those for the cooling period the effectiveness holds 0.9142 ± 0.0305 to 0.9499 ± 0.0329, shown to be accompanied by a bit lower uncertainty. Due to the difference in effectiveness, averaging was applied to calculate mean effectiveness value measured as weighted based on the uncertainties for both periods. As the result, the final averaged effectiveness of the investigated regenerators was found to be within the ranges of 0.9153 ± 0.0278 to 0.9367 ± 0.0296.     

Solvent effects on the rates and mechanisms of reaction of phenols with free radicals

The rates of formal abstraction of phenolic hydrogen atoms by free radicals, Y* + ArOH --> YH + ArO*, are profoundly influenced by the hydrogen-bond-accepting and anion-solvation abilities of solvents, by the electron affinities and reactivities (Y-H bond dissociation enthalpies) of radicals, and by the phenol's ring substituents. These apparently simple reactions can occur by at least three different, nonexclusive mechanisms: hydrogen atom transfer, proton-coupled electron transfer, and sequential proton-loss electron transfer. The delicate balance among these mechanisms depends on both the environment and the reactants. The main features of these mechanisms are described, together with some interesting kinetic consequences.     

Integrated three-dimensional shape and reflection properties measurement system

Creating accurate three-dimensional (3D) digitalized models of cultural heritage objects requires that information about surface geometry be integrated with measurements of other material properties like color and reflectance. Up until now, these measurements have been performed in laboratories using manually integrated (subjective) data analyses. We describe an out-of-laboratory bidirectional reflectance distribution function (BRDF) and 3D shape measurement system that implements shape and BRDF measurement in a single setup with BRDF uncertainty evaluation. The setup aligns spatial data with the angular reflectance distribution, yielding a better estimation of the surface's reflective properties by integrating these two modality measurements into one setup using a single detector. This approach provides a better picture of an object's intrinsic material features, which in turn produces a higher-quality digitalized model reconstruction. Furthermore, this system simplifies the data processing by combining structured light projection and photometric stereo. The results of our method of data analysis describe the diffusive and specular attributes corresponding to every measured geometric point and can be used to render intricate 3D models in an arbitrarily illuminated scene.     

Poly(methyl vinyl ether‐alt‐maleic anhydride) functionalized with 3‐aminophenylboronic acid: A new boronic acid polymer for sensing diols in neutral water

Amidation of poly(methyl vinyl ether‐alt‐maleic anhydride) with 3‐aminophenylboronic acid was used to prepare a new boronic acid polymer. The binding of catechol dye, Alizarin Red S to the polymer obtained resulted in getting a stable, colored sensor which was used to establish association constants with different diols in competitive assay. The binding of different diols was readily detected by color change and absorbance values measured at 450 nm were used to calculate the association constants. The polymer obtained formed high‐affinity complexes with ribonucleosides, particularly cytidine and uridine. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40778.