Doing science at the elbows of experts: Issues related to the science apprenticeship camp

Abstract: The purpose of this paper is to synthesize literature related to apprenticeship learning, the sociology of science, and K‐12 science education to develop a set of characteristics for designing/evaluating participatory science learning experiences. Following this discussion, we further clarify and illuminate the value of these characteristics for science educators by using them as evaluative criteria for characterizing the experiences of 24 middle school learners who embarked on a 2‐week long camp with “real” scientists engaged in “real” research. We also describe how middle school science teachers supported both reflection‐in‐practice and reflection‐on‐practice during the camp, and how an electronic notebook was also leveraged to support both types of reflection. Implications of these characteristics for science education more generally are discussed. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 38: 70–102, 2001     

Mutants of Escherichia coli heat-labile enterotoxin and cholera toxin as mucosal adjuvants

Heat-labile enterotoxin(LT) and cholera toxin(CT) are highly homologous (82 % at the amino acid level), they are the causative factors of travelers diarrhea and cholera respectively[1]. When co-stimulating the surface of the mucosal with antigens, these toxins induce significantly immunological reaction [2]. Because of this character, LT and CT are widely used as mucosal adjuvants in non-human animal models. But the high toxicity and allergenicity caused by IgE antibody (Ab) responded to b…     

Simulating the particle size distribution of rockfill materials based on its statistical regularity

1. Introduction Rockfill has excellent engineering characteristics, such as good compactness, better seepage ability, high density, low sedimentation, high shear strength and so on. So it is widely used in dams, bed of railway and deep foundations[1-2]. Two types of rockfill are commonly used in constructions, that is inartificial rockfill such as gravel and scree, and blasted rockfill, e.g. fragmental stone, macadam and moraine soil. Both types are hetero-geneous mixture composed of numerous …     

An Introduction to the Special Issue: Designing for Virtual Communities in the Service of Learning

In the sociology of childhood and youth, children have been conceptualized as passive subjects on hold, still in the process of becoming—rather than in an effective state of being. In effect, children have been conceptualized as the subjects rather than the objects of the research process. This influence got carried over to digital divide research. The latest thinking in the field has started to define and understand children and young people as heterogeneous, nonpassive, autonomous, diverse, and versatile agents actively appropriating the Internet in meaningful contexts of their everyday lives. This article seeks to move the discourse forward via four parallel binary logistic regressions that assess diverse and socially mediated opportunities needed to learn basic digital skills from a representative sample of 6,602 primary and secondary students from 350 schools and high schools in Catalonia, Spain. Our research shows that the school appears to be playing a secondary role, as compared with children and young people's social practice in heterogenic contexts of everyday life, not only for Internet training but also for providing opportunities to develop and master basic digital skills.     

Relationship Between Load and Swimming Endurance in Humans

Abstract

The purpose of this study was to investigate the effect of load on swimming endurance in humans. Twenty male subjects between the ages of 17 and 24 swam in a vertical to semi-vertical position (treaded water using arms and legs) until exhausted or until an hour had elapsed. This was done with loads of 0, 2, 4, 6, 8, 10, 15, 20, 25, and 30 percent of the body weight. The lead used as a weight was placed around the waist of the swimmer. The times were recorded at each load and the means determined and plotted. The relationship between load and endurance was close and curvilinear. Heavier individuals were at a slight disadvantage in this swimming test which used percentage of body weight as a measure of load. Among good swimmers a load of 4 percent of the body weight did not decrease swim time appreciably, while a load of 30 percent reduced swim time to a matter of seconds.     

种内竞争对桔小实蝇种群动态的影响

研究种内竞争对桔小实蝇的个体大小、存活率、生物量及产卵量的影响,并进行了模拟分析。对影响种群动态的诸要素建立模糊集,用贴近度方法进行关键要素分析。在种内竞爭条件下,成虫产卵量是影响世代趋势指数的关键要素,蛹生物量是影响下代虫口密度的关键要素。     

应力敏感性承压含水层渗流规律研究

基于应力敏感性渗流特征,针对承压含水层完全井,建立了带有渗透率应力敏感性系数的渗流数学模型。计算结果表明随着应力敏感性系数系数的增大,水位降深-流量关系曲线逐渐偏离线性关系,应力敏感性系数越大,在相同的水位降深条件下,出水量越小;同时,随着应力敏感性系数的增大,水头损失幅度也增大,任一流量下,应力敏感性系数越大,靠近井底附近位置处的水头损失幅度也越大。     

电激法转移质粒扩大苏云金杆菌杀虫谱

应用高压电激法,把载有表达不同杀虫谱晶体蛋白基因的两种质粒同时转入晶体缺陷型的BT菌株,或者把载有表达单一晶体蛋白基因的质粒转入不同亚种且产生晶体的天然BT菌株中,通过生物测定法,快速而简便地筛选出杀虫谱扩大及杀虫毒力提高的重组菌株。所筛选到的菌株产生的伴孢晶体,同时对鳞翅目及双翅目昆虫幼虫有毒杀作用,并且重组菌株所产生的伴孢晶体的形状有异于其出发菌株的伴孢晶体。     

Research on Small-Scale Solar Magnetic Fields and Activities

It has been known that there are different kinds of small-scale active phenomena on the Sun.They are classified into spicules,macrospicules,and H-alpha jets,X-ray jets,etc.,according to their sizes,velocities, lifetimes,and so on.All these phenomena are related to small-scale magnetic fields.The problems of solar upper     

Gamma-ray Bursts:Progresses at Purple Mountain Observatory

A gamma-ray burst(GRB) is an extremely luminous flash of gamma rays that occurs as the result of an explosion,and is thought to be associated with the formation of a black hole.Most GRBs are billions of light years away from Earth,implying that the explosions are both extremely energetic(a typical burst releases as