创业不问出处？家庭出身与农民创业的关系研究

农民的决策行为受到家庭因素的制约,而家庭出身将如何影响到农民的创业行为,这仍旧是一个悬而未决的重要研究问题。本文基于上海财经大学千村调查的数据,就体制内精英家庭出身与农民创业之间的关系进行了分析,并得到以下研究结论：家庭出身的优越性将显著提高农民的创业动机,相比于普通出身或寒门出身,那些出身于体制内精英家庭的农民更倾向于选择创业。同时,体制内精英家庭出身对农民创业的影响还受到家庭社会地位的制约,即在那些社会地位较高的家庭,体制内精英家庭出身对农民创业所产生的积极效应更为明显。进一步分析表明,个体人力资本将影响到农民创业与否的选择,过高或过低的人力资本均将降低农民创业的动力,但人力资本对于精英家庭出身的调节效应并不显著。本文从精英家庭出身入手,探索家庭层面的非市场力量对农民创业的作用机制,不仅有利于挖掘农民创业的内在动因,而且拓展了农村精英的研究维度,为传统精英理论的发展提供新的研究视角。     

Optofluidic planar reactors for photocatalytic water treatment using solar energy

Optofluidics may hold the key to greater success of photocatalytic water treatment. This is evidenced by our findings in this paper that the planar microfluidic reactor can overcome the limitations of mass transfer and photon transfer in the previous photocatalytic reactors and improve the photoreaction efficiency by more than 100 times. The microreactor has a planar chamber (5 cm×1.8 cm×100 μm) enclosed by two TiO(2)-coated glass slides as the top cover and bottom substrate and a microstructured UV-cured NOA81 layer as the sealant and flow input∕output. In experiment, the microreactor achieves 30% degradation of 3 ml 3×10(-5)M methylene blue within 5 min and shows a reaction rate constant two orders higher than the bulk reactor. Under optimized conditions, a reaction rate of 8% s(-1) is achieved under solar irradiation. The average apparent quantum efficiency is found to be only 0.25%, but the effective apparent quantum efficiency reaches as high as 25%. Optofluidic reactors inherit the merits of microfluidics, such as large surface∕volume ratio, easy flow control, and rapid fabrication and offer a promising prospect for large-volume photocatalytic water treatment.     

Release monitoring of single cells on a microfluidic device coupled with fluorescence microscopy and electrochemistry

A method for monitoring the biological exocytotic phenomena on a microfluidic system was proposed. A microfluidic device coupled with functionalities of fluorescence imaging and amperometric detection has been developed to enable the real-time monitoring of the exocytotic events. Exocytotic release of single SH-SY5Y neuroblastoma cells was studied. By staining the cells located on integrated microelectrodes with naphthalene-2,3-dicarboxaldehyde, punctuate fluorescence consistent with localization of neurotransmitters stored in vesicles was obtained. The stimulated exocytotic release was successfully observed at the surface of SH-SY5Y cells without refitting the commercial inverted fluorescence microscope. Spatially and temporally resolved exocytotic events from single cells on a microfluidic device were visualized in real time using fluorescence microscopy and were amperometrically recorded by the electrochemical system simultaneously. This coupled technique is simple and is hoped to provide new insights into the mechanisms responsible for the kinetics of exocytosis.     

Evaluation of small‐group teaching in human gross anatomy in a Caribbean medical school

Although there are a number of medical schools in the Caribbean islands, very few reports have come out so far in the literature regarding the efficacy of small‐group teaching in them. The introduction of small‐group teaching in the gross anatomy laboratory one and a half years ago at St. Matthew's University (SMU) on Grand Cayman appears to have had a significant positive impact on the academic achievement of students in anatomy. This study surveyed the responses of the students to the small‐group learning method in gross anatomy at SMU using a structured questionnaire. The results show that our students prefer this small‐group learning method over a completely self‐directed method in the gross anatomy lab because the study materials were carefully chosen and the study objectives were demonstrated by the resource person. However, teacher‐centered teaching was deliberately avoided by fostering problem‐solving skills in the anatomy lab sessions. Another aim of the small‐group teaching at SMU was to develop the interpersonal and communication skills of the students, which are important in their later education and career. Anat Sci Ed 1:19–22, 2008. © 2007 American Association of Anatomists.     

Theoretical elastoplastic analysis for foundations with geosynthetic-encased columns

As a new technique in ground improvement, geosynthetic-encased columns (GECs) have promising applications in soft soil foundation. By assuming yielding occurs in the columns while the surrounding soil and the geosynthetic remain elastic, an elastoplastic analytical procedure for foundations improved by GECs is proposed. The radial stresses that the geosynthetic provides and the elastoplastic deformations of the foundation resting on a rigid base are derived. A comparison with finite element analysis shows that the proposed method is effective and can provide a reasonable prediction of a GEC??s deformation. Subsequent parametric analysis indicates that higher geosynthetic stiffness leads to better performance of the composite foundation. The optimum length of encasement is related to the load acting on the foundation and the permissible vertical and radial displacements of the column. Moreover, as the dilation angle of the column increases, the settlement decreases, especially under high loading. The influence of the encasement is more significant in soils with smaller elastic modulus.     

Effects of a phonological awareness program on English reading and spelling among Hong Kong Chinese ESL children

This study investigated the effects of a 12-week language-enriched phonological awareness instruction on 76 Hong Kong young children who were learning English as a second language. The children were assigned randomly to receive the instruction on phonological awareness skills embedded in vocabulary learning activities or comparison instruction which consisted of vocabulary learning and writing tasks but no direct instruction in phonological awareness skills. They were tested on receptive and expressive vocabulary, phonological awareness at the syllable, rhyme and phoneme levels, reading, and spelling in English before and after the program implementation. The results indicated that children who received the phonological awareness instruction performed significantly better than the comparison group on English word reading, spelling, phonological awareness at all levels and expressive vocabulary on the posttest when age, general intelligence and the pretest scores were controlled statistically. The findings suggest that phonological awareness instruction embedded in vocabulary learning activities might be beneficial to kindergarteners learning English as a second language.     

BGP路由摆动抑制机制与路径探索

路由摆动抑制是普遍用于网络路由协议的一种机制。其目的在于通过暂时抑制那些短期内发生快速变化的路由，而限制不稳定路由的全局影响。普遍认为这一抑制机制有助于Internet全局路由的稳定性，但研究表明BGP的路径探索可能错误地引发抑制，甚至仅仅一次路由摆动都可能导致路由收敛时间的大大增加。     

Application of system dynamics for assessment of sustainable performance of construction projects

INTRODUCTION Sustainable development is commonly definedas meeting the needs of the present without compro-mising the ability of future generations to meet theirown needs (WCED, 1987). All industries, includingthe construction industry should contribute to themission. Compared to other industries, constructionactivities are generally considered to have more im-pact on the environment, which provides the basicconditions for the sustainability and development oflife on the Earth. The…     

Contextualising the career pathways of women principals in Hong Kong: a critical examination

The fields of gender and educational leadership have been enriched recently by analyses of national case studies from non-western contexts. By contextualising women’s career development, these studies highlight the importance of including experiences other than those generated from Anglo-American-Australian contexts, thus broadening our knowledge base for more nuanced theorisation in the field. This paper contributes a close examination of the career histories of eight female primary school principals in Hong Kong. Our analyses identify a range of facilitators, including the expansion of promotion opportunities, strong values placed on education and training, professional encouragement and support and help in relieving family responsibilities. Valuable these factors may be, but we argue that they are incidental, informal, familial and individual, and incur the costs of burn-out and guilt. The discussion not only underlines the significance of case study and cultural and contextual specificities, it also provides a nuanced understanding of Chinese patriarchy.     

我国少数民族本科预科课程教学定位的基本依据与原则探析

民族预科课程教学定位问题一直困扰着我国民族预科教育,影响教学质量的德定和提高.文章分析了预科课程教学的特殊性,从学生民族文化背景的多样性与教学标准统一要求相协调、知识传授与思想教育相结合、知识积累与学习能力发展相结合、以教师为主导与充分发挥学生主体性相结合、尊重学生文化背景与发挥多元文化的积极作用相结合等10个方面提出了少数民族本科预科课程教学定位的基本原则,旨在促进民族预科教学的科学化、规范化.