Use of single wall carbon nanohorns in polymeric electrolyte fuel cells

Single wall carbon nanohorns (SWNH), produced by AC arc discharge in air, were used as Pt and PtRu supports in polymer electrolyte membrane fuel cells (PEMFC). These electrocatalysts were compared with equivalent electrocatalysts supported on commercial carbon back. The SWNH were characterized by differential thermal analysis (DTA), TEM, SEM, and XRD. The produced SWNH were 84.5 wt% pure, containing 3 wt% of amorphous carbon and 12.5 wt% of graphitic carbon. SWNH were used as electrocatalyst supports and tested in the electrodes of two types of polymer electrolyte fuel cells: H₂-fed PEMFC and direct methanol fuel cells (DMFC). The electrocatalyst nanoparticles anchored on both carbon supports were ca. 2.5 nm in diameter obtained by employing ethylene glycol as the reducing agent. The use of SWNH showed catalytic activities 60% higher than using carbon black as the electrocatalyst support in both types of fuel cells.     

Biased allocation of faces to social categories.

Three studies show that social categorization is biased at the level of category allocation. In all studies, participants categorized faces. In Studies 1 and 2, participants overallocated faces with criminal features—a stereotypical negative trait—to the stigmatized Moroccan category, especially if they were prejudiced. On the contrary, the stereotype-irrelevant negative trait stupid did not lead to overallocation to the Moroccan category. In Study 3, using the stigmatized category homosexual, the previously used negative trait criminal—irrelevant to the homosexual stereotype—did not lead to overallocation, but the stereotype-relevant positive trait femininity did. These results demonstrate that normative fit is higher for faces with stereotype-relevant features regardless of valence. Moreover, individual differences in implicit prejudice predicted the extent to which stereotype-relevant traits elicited overallocation: Whereas more negatively prejudiced people showed greater overallocation of faces associated with negative stereotype-relevant traits, they showed less overallocation of faces associated with positive stereotype-relevant traits. These results support our normative fit hypothesis: In general, normative fit is better for faces with stereotypical features. Moreover, normative fit is enhanced for prejudiced individuals when these features are evaluatively congruent. Social categorization thus may be biased in itself. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Job Allocation Strategies with User Run Time Estimates for Online Scheduling in Hierarchical Grids

We address non-preemptive non-clairvoyant online scheduling of parallel jobs on a Grid. We consider a Grid scheduling model with two stages. At the first stage, jobs are allocated to a suitable Grid site, while at the second stage, local scheduling is independently applied to each site. We analyze allocation strategies depending on the type and amount of information they require. We conduct a comprehensive performance evaluation study using simulation and demonstrate that our strategies perform well with respect to several metrics that reflect both user- and system-centric goals. Unfortunately, user run time estimates and information on local schedules does not help to significantly improve the outcome of the allocation strategies. When examining the overall Grid performance based on real data, we determined that an appropriate distribution of job processor requirements over the Grid has a higher performance than an allocation of jobs based on user run time estimates and information on local schedules. In general, our experiments showed that rather simple schedulers with minimal information requirements can provide a good performance.     

Homonuclear Magnetization Transfer Experiments Using Isotropic and Nonisotropic Mixing Schemes

The principles of homonuclear magnetization transfer via isotropic and non-isotropic mixing schemes are discussed. Practical aspects of such experiments concern the minimization of the generation of multiple quantum coherence, minimization of rf power requirements, suppression of NOEs during mixing and minimization of relaxation losses. The analogy between these experiments and heteronuclear decoupling is briefly discussed. The efficiencies of several mixing schemes are compared and it is demonstrated experimentally that the resolution and sensitivity of the homonuclear cross polarization methods can be superior to the conventional COSY experiment.     

Frequency and quality of parental communication as antecedents of adolescent smoking cognitions and smoking onset.

The present study examines whether aspects of parental communication about smoking function as antecedents of adolescent smoking cognitions. In this longitudinal full-family study (428 families), parent and adolescent reports were used to assess parental communication. Concepts of the Theory of Planned Behavior were measured among adolescents. Differences between older and younger siblings within the family were examined. Cross-sectionally, frequency and quality of communication were associated with smoking cognitions. Longitudinally, only quality of communication preceded smoking cognitions. This effect was mainly found for younger siblings. The results of this study emphasize the importance of quality of parental communication rather than frequency. Communication patterns based on mutual respect and equality help to prevent adolescent smoking onset. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FPGA热特性建模的实际功率测量法

在时钟频率和门数不断增长的背景下,很多包含高性能FPGA(现场可编程门阵列)的系统通常都需要一个作彻底分析的热模型.我在做一个包含FPGA的项目时,发现自己没有足够的数据来准确判定FPGA的功耗,而我的机械工程向行需要用功耗数据来构建一个系统模型,供Flomerics的Flotherm软件作热分析.     

Normal puerperium and breast-feeding

Mothers who have just given birth need support from medical staff and also from their home surroundings. The type of support given to mothers and their new babies varies in different countries and cultures, but should be equally adequate and beneficial. Breast-feeding, as the very best method of early nutrition of the newborn, is the central event of puerperium. Its importance, and other practical approaches during this period are discussed and reviewed.     

Infrared and Structural Properties of Y1−xNdxBa2Cu3O7−δ (0 ≤ x ≤ 1)

Infrared and structural properties of Y_1?x Nd _x Ba₂Cu₃O_7?δ (0 ≤ x ≤ 1) were investigated using infrared absorption spectroscopy and X-ray powder diffraction. The unit cell parameters of the samples were defined using X-ray diffraction data. The resistance measurements showed that the samples revealed superconductivity in the temperature range of 80–100 K. It was observed that by the substitution of Nd to Y in YBa₂Cu₃O_{7 ? δ} IR band at 573 cm^?1 that is assigned as Cu–O axial antisymmetric stretching mode shifts to 533 cm^?1 while the band at 620 cm^?1 that is due to Cu–O symmetric stretching mode in YBa₂Cu₃O_7?δ shifts to 588 cm^?1.     

Visual perception of numerosity in infancy.

Numerosity was defined as an invariant property of a collection of objects specifying its numerical size. Infants looked at displays of small numerosities that changed optic structure such that size was not tied to certain static or dynamic configurational properties of the display but remained constant across patterns of optic motion. The displayed figures moved continuously and at a constant speed. The trajectories were irregular and could produce occlusion of objects. The task used involved infant-controlled habituation of visual looking time. At ages 5 mo, 8 mo, and 13 mo, 44 infants were tested for the numerosities 2, 3, and 4 in 3 randomly ordered sessions. The results demonstrated that infants from the age of at least 5 mo perceive small numerosities. It appears that discrimination of units, rather than discrimination of characteristic patterns, underlies numerosity perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How to assess the listening comprehension skills of prereaders.

In Exp I, a listening span test, a word span test, and a listening comprehension test were administered to 24 preschoolers (ages 3 yrs 2 mo to 5 yrs 2 mo) to determine whether listening span correlated well with Ss' listening integration skills. In Exp II, with 20 preschoolers (aged 3 yrs 4 mo to 5 yrs) a longer listening comprehension test was administered in which comprehension depended on the integration of at least 2 important ideas in the narrative. Results show that the measure of listening span was a successful measure of the listening comprehension skills of prereaders because it tapped skills at an intermediate level of complexity. The word span measure involved lower-level processes like word encoding and lexical access, but listening span captured many of the processes of normal sentence comprehension. In addition, listening span was easy to administer and had high predictive validity. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)