The classroom environment and students' reports of avoidance strategies in mathematics: A multimethod study.

The relation between the learning environment (e.g., students' perceptions of the classroom goal structure and teachers' instructional discourse) and students' reported use of avoidance strategies (self-handicapping, avoidance of help seeking) and preference to avoid novelty in mathematics was examined. Quantitative analyses indicated that students' reports of avoidance behaviors varied significantly among classrooms. A perceived emphasis on mastery goals in the classroom was positively related to lower reports of avoidance. Qualitative analyses revealed that teachers in high-mastery/low-avoidance and low-mastery/high-avoidance classrooms used distinctively different patterns of instructional and motivational discourse. High incidence of motivational support was uniquely characteristic of high-mastery/ low-avoidance classrooms, suggesting that mastery goals may include an affective component. Implications of the results for both theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effectiveness of Early Head Start for 3-Year-Old Children and Their Parents: Lessons for Policy and Programs.

Early Head Start, a federal program begun in 1995 for low-income pregnant women and families with infants and toddlers, was evaluated through a randomized trial of 3,001 families in 17 programs. Interviews with primary caregivers, child assessments, and observations of parent-child interactions were completed when children were 3 years old. Caregivers were diverse in race-ethnicity, language, and other characteristics. Regression-adjusted impact analyses showed that 3-year-old program children performed better than did control children in cognitive and language development, displayed higher emotional engagement of the parent and sustained attention with play objects, and were lower in aggressive behavior. Compared with controls, Early Head Start parents were more emotionally supportive, provided more language and learning stimulation, read to their children more, and spanked less. The strongest and most numerous impacts were for programs that offered a mix of home-visiting and center-based services and that fully implemented the performance standards early. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential Scanning Calorimetry (DSC) and Thermodynamic Prediction of Liquid Fraction vs Temperature for Two High-Performance Alloys for Semi-Solid Processing (Al-Si-Cu-Mg (319s) and Al-Cu-Ag (201))

Metallurgical and Materials Transactions A - There is a need to extend the application of semi-solid processing (SSP) to higher performance alloys such as 319s (Al-Si-Cu-Mg) and 201 (Al-Cu-Ag). The...     

When 3-year-olds pass the appearance–reality test.

68 3-yr-olds received a standard appearance–reality task along with either a trick task, in which the appearance question was placed in the context of a deceptive game, or a reduced information processing task, in which a dual object (e.g., a sponge-rock) was presented along with an object that matched the dual object's identity (a sponge) and one that matched the dual object's appearance (a rock). Children were more likely to pass either the trick or reduced information processing task and fail the standard than the reverse. Thus, 3-yr-olds can grasp the distinction between appearance and reality (a) when their goal is to trick someone, which may prime them to think about the other's mental state, and (b) when they do not need to hold conflicting object identities in mind at the same time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemical cryoprotection for structural studies

With the ascendency of techniques for ultrarapid cooling and the successful control of ice crystal damage by purely physical means, it has become necessary to make a case for the continued use of chemical antifreeze agents in any circumstances. These circumstances include the need to explore tissues deeper than those superficial layers, whose morphology can be preserved by ultrarapid cooling, the avoidance of superficial areas of damage inflicted by dissection and tissue slicing, and situations where the growth of ice crystals must be controlled throughout the specimen, as for example for the cutting of frozen sections. The control of ice crystal damage would ideally be by the avoidance of any freezing at all but in practice can be seen in terms of the control of ice crystal size, which in turn depends on the density of nuclei that develop in the specimen and the rate of accretion of water molecules to the crystallites that form on these nuclei. Chemical antifreeze agents act in a variety of ways to increase the density of nuclei and/or to reduce the rate of growth of ice crystals: by promoting nucleation, by enhancing subcooling and by increasing the viscosity of the extracellular medium. In this way, large numbers of small ice crystals are produced. The different types of cryofixative agent each have their own advocates, advantages, special applications and drawbacks and these must be taken into account when considering the range of methods available for the analysis of cryofixed material.     

Classification of brain neoplasm from multi-modality MRI with the aid of ANFIS classifier

Multidimensional Systems and Signal Processing - In medical Image processing, the chief objective is to detect Neoplasm effectively. Neoplasm is basically a sort of abnormal excessive cell growth...     

分立器件产业永不没落的朝阳产业

[编者按]作为半导体产业的两大分支之一,分立器件产业在中国保持着悠久的发展历史,随着产业的不断发展,一些新技术、新工艺、新产品的不断涌现,这些都将推动着分立器件市场的蓬勃发展.本刊特约业内著名分立器件专家和企业家杨克武、王新潮先生谈了行业热点问题.他们独到的见解、精辟的分析,给予读者启示,让我们看到了分立器件产业的希望和未来.     

Distributed node selection for threshold key management with intrusion detection in mobile ad hoc networks

In mobile ad hoc networks (MANETs), identity (ID)-based cryptography with threshold secret sharing is a popular approach for the security design. Most previous work for key management in this framework concentrates on the protocols and structures. Consequently, how to optimally conduct node selection in ID-based cryptography with threshold secret sharing is largely ignored. In this paper, we propose a distributed scheme to dynamically select nodes with master key shares to do the private key generation service. The proposed scheme can minimize the overall threat posed to the MANET while simultaneously taking into account of the cost (e.g., energy consumption) of using these nodes. Intrusion detection systems are modeled as noisy sensors to derive the system security situations. We use stochastic system to formulate the MANET to obtain the optimal policy. Simulation results are presented to illustrate the effectiveness of the proposed scheme.