Guiding collaborative revision of science explanations

International Journal of Computer-Supported Collaborative Learning - This paper illustrates how the combination of teacher and computer guidance can strengthen collaborative revision and identifies...     

食用农产品中产志贺毒素大肠埃希菌污染与家庭厨房食物安全现状分析及防控措施

本文通过对食用农产品中产志贺毒素大肠埃希菌(STEC)来源与传播途径分析,阐述了STEC污染与家庭厨房食物安全之间的关系,并对当前世界各国食品中STEC的监管情况进行阐述,从而提出我国控制食用农产品中STEC进入家庭厨房的解决方案。     

The idealized self and the situated self as predictors of employee work behaviors.

This article presents a model integrating research on idealized and situated selves. Our key premise is that identity-relevant behaviors are most likely to occur in the workplace when identities are psychologically central and activating forces make those identities salient. Analysis of matched data from 278 employees, supervisors, and organizational records generally supported our model. Helping identity and industrious work identity were positively associated with related role behaviors only when time-based occupancy in the role of organization member was high. Industrious work identity was positively associated with role behaviors only when reflected appraisals from coworkers were consistent with that identity. In contrast, reflected appraisal of helping identity had an independent relationship with identity-relevant role behaviors. Results demonstrate the importance of theory linking the idealized self and the situated self to understanding identity relations with work performances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 100-Year Review: Calf nutrition and management

The first calf paper, published in the May 1919 issue of the Journal of Dairy Science (JDS), described factors affecting birth body weight of different breeds of calves. Other studies were done on nonmilk ingredients, growth charts were developed, and early weaning was followed to conserve milk fed to calves. Calf papers did not report use of statistics to control or record variation or to determine whether treatment means were different. Many experiments were more observational than comparative. Typically fewer than 5 calves, and sometimes 1 or 2 calves, were used per treatment. During the next 20 yr, calf studies increased and included colostrum feeding, milk and milk replacer feeding, minerals and vitamins, and fats and oils. Many concepts fundamental to current knowledge and understanding of digestion, rumen development, and milk replacer formulation were developed during this period. In addition, the concept of using antibiotic growth promoters in dairy calf diets was first evaluated and developed during the 1950s. During the 20-yr period of January 1957 through December 1976, a large number of universities in the United States and 1 in Canada contributed almost 150 papers on a variety of calf-related topics. These topics included genetics, physiology of the calf, review of calf immunity, antibiotic feeding, and milk replacer ingredients. This became the golden era of calf rumen development studies, which also engendered studies of calf starter rations and ingredients. A classic review of management, feeding, and housing studies summarized research related to calf feeding and management systems up to that point with an emphasis on maintaining calf growth and health while reducing labor and feed costs. It was also during this period that metric measurements replaced English units. In the 20-yr period from 1977 to 1996, more than 400 articles on calf nutrition and management were published in JDS. With the growing research interest in calves, a paper outlining standardized procedures for conducting and reporting data from calf experiments was first published. A very active area of calf nutrition research from the late 1970s to the mid 1980s was colostrum quality, feeding, and preservation; more than 60 such research articles were published in the journal during this time. Various nonmilk protein sources were evaluated. Extensive studies were done evaluating trace and major mineral requirements in calves along with some vitamin studies. Throughout the 1970s, 1980s, and 1990s, the primary objective of most calf research was how to wean healthy, adequately grown calves at an early age—generally less than 30 d of age. This program was reviewed in a 1979 publication. Research on calf starter ingredients, nutrient composition, and additives was minimal in the 1980s and 1990s given the importance of starter intake to the success of early weaning, but the role of water intake in starter intake and growth was established. Research on issues with calves continued to increase during the last 20-yr period as evidenced by publication of more than 580 articles in JDS as well as many more in other refereed journals. In addition to papers contributed by several universities in the United States and Canada, the number of papers authored by scientists at universities and institutes in other countries increased dramatically during this period. Factors influencing colostral antibody absorption, heat treatment of colostrum, and efficacy of colostrum supplements and replacers were reported. Most studies in this period related to nutrition. Studies were published supporting greater neonatal growth rates from feeding more milk replacer but with a higher crude protein content than traditional. Protein energy effects on growth and body composition were evaluated in concert with greater growth rates. Milk and nonmilk protein sources in milk replacers along with AA supplementation were evaluated. Limited studies were done with fat sources and fatty acid supplementation along with trace minerals and fat-soluble vitamins. Waste milk feeding and heat treatment became more prevalent. Studies established starter ingredient palatability and use of forage when fed with pelleted starters. With the advent of automatic milk and milk replacer feeders, factors influencing how and when to wean were established. Research programs established factors affecting calf behavior and welfare. Several databases were evaluated along with various published studies, and established calf growth during the first 2 mo was subsequently reflected in first- and later-lactation milk production of those calves. A new area of calf research that emerged from 1997 on was the effects of maternal environment and nutrition on calf health, growth, and future productivity. From a mechanistic standpoint, the field of epigenetics seems likely to explain many of these phenomena. Some possibilities for future calf nutrition and management were elaborated.     

Process Capability Improvement for Multistage Processes

While the quality control procedures for multistage has been considerably studied, multistage process capability analysis has not been explored much at all. Fostering on the recent development of the multistage process variation transmission model, a multistage process capability analysis algorithm is developed to prioritize process improvement efforts. The application of algorithm is demonstrated with two 2-stage industrial process examples and a 4-stage process example for its expandability.     

Adapting instruction to the cognitive demands of learning to program.

This study investigated how instructional practices influence what students learn in Pascal programming classes. The study contrasted 8 introductory and 8 Advanced Placement (AP) level courses because goals of teachers, classroom activities, and assigned tasks differ. Introductory students primarily learn syntax and AP students learn to plan and debug complex problems. These differing cognitive demands would seem to require different instructional practices. In order to establish instructional practices, students reported teaching strategies, course structure, and classroom resources. To demonstrate programming proficiency, students modified and analyzed a computer program. Programming proficiency varied as a function of instructional practices and class level. Introductory students benefited from direct instruction, and AP students performed better with less direct guidance and more opportunities for autonomy. Characteristics of effective programming instruction vary depending on the cognitive demands of courses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microemulsion for Intradermal Delivery Of Cetyl Alcohol and Octyl Dimethyl PABA

A water-in-oil microemulsion was prepared to deliver cetyl alchohol [I] octyl dimethyl PABA or Padimate-O [II] in vitro using human and hairless mouse skin. A standard Franz diffusion cell and a microsectiong cryostat microtome were used to quantify the rate and the depth of penetration and the results were compared in the percent does penetrated for this microemulsion and two macroemulsion formulations, namely a cream and a lotion. It appeared that the microemulsion had the ability to deliver [I] into the skin 2-6 times faster and at least twice as much as that with the other two formulations. Furthermore, the absorption of [I] from the cream or lotion product could bel enhanced by as much as 50-250% if the skin had been pretreated with microemulsion prior to product application. The advantage of using a microemulison to acheieve deeper and faster penetratin of the permeating compunds was clearly demonstreated in this study.     

Mixed mode fracture behaviour of steel fibre reinforced concrete

In this paper, results are reported for a series of discrete end hooked and straight fibre pullout tests subjected to mixed mode action with the results compared to that of discrete fibres pulled out in Mode I (tensile) and Mode II (shear) fracture. As has been previously observed from Modes I and II fracture tests, the snubbing effect dominates the behaviour of fibres at large fibre bending angles. At large fibre bending angles, considerable slip and crack separation occurred prior to the fibres being engaged in taking load and fibres that are inclined close to the cracked surface are ineffective in carrying load. The results of the test were compared with the fibre engagement and bond stress models in the Unified Variable Engagement Model (UVEM). A good correlation is observed for the UVEM model with the test data and provides further confirmation of the validity of the UVEM model to predict the mix mode fracture of steel fibre reinforced concrete.     

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