State anxiety and motor performance: testing the conscious processing hypothesis

Previous research has argued that skills acquired explicitly are more likely to fail under stressful conditions than skills that have been learned implicitly. The present study addressed an alternative explanation for the robustness under stress of implicit task performance. As implicit learners acquired the skill of golf putting while generating random letters, it is possible that they became desensitized to self-generated verbalizations and thus immune to the effects of competitive anxiety. We tested this interpretation while controlling for a further rival hypothesis generated by Eysenck's Processing Efficiency Theory. We also examined the effect of increased state anxiety on the kinematic processes underlying performance breakdowns. For task performance, we found evidence that partially supported the conscious processing hypothesis, while the results of the kinematic analysis of the putting stroke were equivocal. Analysis of self-reported effort scores provided partial support for processing efficiency theory.     

The role of gender constancy in early gender development

Kohlberg's (1966) hypothesis that the attainment of gender constancy motivates children to attend to gender norms was reevaluated by examining these links in relation to age. Ninety-four 3- to 7-year-old children were interviewed to assess whether and how constancy mediates age-related changes in gender-related beliefs. As expected, results indicated a general pattern of an increase in stereotype knowledge, the importance and positive evaluation of one's own gender category, and rigidity of beliefs between the ages of 3 and 5. Moreover, the stability phase, rather than full constancy, mediated some of these relations. After age 5, rigidity generally decreased with age, with relations primarily mediated by consistency.     

The development of subjective group dynamics: children's judgments of normative and deviant in-group and out-group individuals

A developmental model of subjective group dynamics suggests that social identity is sustained first by intergroup biases and later by intragroup biases. In this study 476 English children 5 to 11 years old evaluated the English and German soccer teams, and judged in-group or out-group members whose attitudes toward the teams was normative versus antinormative. Children of all ages expressed intergroup bias. Differential evaluation against in-group deviants and in favor of out-group deviants strengthened with age. Understanding of targets' relative acceptability (differential inclusion) among in-group and out-group members mediated the effects of age and intergroup bias on intragroup bias. Identification with the in-group moderated the effects only among older children.     

Countermovement jump performance assessment using a wearable 3D inertial measurement unit

The aim of this study was to validate a wearable inertial measurement unit (IMU), containing a 3D accelerometer and gyroscope, for the estimation of countermovement jump height. The absolute vertical acceleration of the IMU positioned on the back of the participant at L5 level, compensated for trunk rotations, was used to obtain jump height by applying the equation of free-fall to the motion of the IMU. The methodology was tested on 28 participants performing five countermovement jumps each. A reference value for this quantity was obtained using stereophotogrammetry (35.4 cm, s = 4.9). Jump height scores obtained using the proposed methodology (35.9 cm, s = 5.5) presented no significant difference with respect to stereophotogrammetry (P = 0.61). A low bias of 0.6 cm confirmed the accuracy of the estimate, which also showed a high (r = 0.87) and significant (P < 0.0001) correlation with reference values. Furthermore, without compensating accelerations for trunk rotation, jump height was largely underestimated (P < 0.0001) (bias: -12.7 cm) and poorly associated (r = 0.31) with stereophotogrammetry. The results of this study show that the estimation of jump height using inertial sensors leads to accurate results when the measured accelerations are corrected for trunk rotations.     

饮用水的砷中毒危机

饮水中潜藏的砷可能令世界各地5000余万人严重中毒。目前正在孟加拉国试点的一些措施或许有助于预防砷的危害。     

Bromo-oxidation reaction in enzyme-entrapped alginate hollow microfibers

In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure.     

Reconciling rising serials costs, the serials budget, and reference needs in a medical library serials retrenchment program: a methodology

Devising a coherent serials retrenchment plan while maintaining quality reference service is a dilemma faced by increasing numbers of medical librarians. In 1991, the staff of the Shiffman Medical Library, Wayne State University, began to address increasing serials budget reductions that by 1994 amounted to a projected 20% maximum cut. The resulting retrenchment plan combined an ongoing serials use study, faculty and librarian reviews of cancellation lists, and systematic refinements in interlibrary cooperation and document delivery service. The Shiffman plan provides a constructive framework that can be adapted to other medical libraries facing immediate, major serials retrenchment.     

等离子体粒子加速器

等离子体中产生的电场能够使电子加速以获得高能。这个方法可望使场强比能量最大的传统加速器的场强高出10，000倍。     

基于数学形态学的锅炉火焰图像骨架提取

本基于二值数学形态学，建立了数字图像骨架提取方法，并给出了相应的算法．同时，对结构元素序列进行了研究，结构元素序列的选取是骨架提取的关键．最后，应用数字图像骨架提取算法，对锅炉火焰图像进行了处理．处理结果表明，所提取的骨架能够准确地描述火焰图像的几何形状．     

Adolescents' working models and styles for relationships with parents, friends, and romantic partners

This study examined the links among adolescents' representations of their relationships with parents, friends, and romantic partners. Sixty-eight adolescents were interviewed three times to assess their working models for each of these types of relationships. Working models of friendships were related to working models of relationships with parents and romantic partners. Working models of relationships with parents and romantic partners were inconsistently related. A similar pattern of results was obtained for self-report measures of relational styles for the three types of relationships. Perceived experiences were also related. Specifically, support in relationships with parents tended to be related to support in romantic relationships and friendships, but the latter two were unrelated. On the other hand, self and other controlling behaviors in friendships were related to corresponding behaviors in romantic relationships. Negative interactions in the three types of relationships also tended to be related. Taken together, the findings indicate that the representations of the three types of relationships are distinct, yet related. Discussion focuses on the nature of the links among the three.