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111.
Manipulation of magnetic beads plays an increasingly important role in molecular diagnostics. Magnetophoresis is a promising technique for selective transportation of magnetic beads in lab-on-a-chip systems. We investigate periodic arrays of exchange-biased permalloy microstripes fabricated using a single lithography step. Magnetic beads can be continuously moved across such arrays by combining the spatially periodic magnetic field from microstripes with a rotating external magnetic field. By measuring and modeling the magnetophoresis properties of thirteen different stripe designs, we study the effect of the stripe geometry on the magnetophoretic transport properties of the magnetic microbeads between the stripes. We show that a symmetric geometry with equal width of and spacing between the microstripes facilitates faster transportation and that the optimal period of the periodic stripe array is approximately three times the height of the bead center over the microstripes. 相似文献
112.
Maquiladoras, border factories and assembly operations in Mexico, are an important source of foreign direct investment and jobs. In the past decade, there has been rapid growth in the number of maquiladoras. It is estimated that in 1999 there were 3,219 maquiladoras employing over 1 million workers. Along with this growth, there has been a structural transformation of the industry. As a result of major investments in the automobile and electronics sectors, there has been a shift from low‐wage manufacturing towards total quality manufacturing [TQM], including flexible manufacturing and just‐in‐time inventory systems. Since their inception maquiladoras have suffered from high turnover and absenteeism. These two problems serve as major obstacles to the successful implementation of TQM programs and increase the cost of recruitment and training. This paper surveys the literature and presents a theory that relates the success of TQM programs to cross‐cultural management. Our hypothesis is that strategic quality initiatives like TQM work best when they incorporate top leadership involvement and worker‐focused human resources policies integrated to provide both salary and non‐salary benefits that increase worker satisfaction. We hold that effective cross‐cultural management based upon top leadership involvement responds to deep‐seated cultural needs by constructing approximations of traditional elements of Mexican culture. Therefore, incorporating and respecting traditional culture and the worker's need for community will positively influence worker acceptance of TQM programs and reduce turnover. 相似文献
113.
Mikael Swarén Anders Eriksson 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):190-201
Pacing strategies in cross-country skiing have been investigated in several studies. However, none of the previous studies have been verified by collected skiing data giving the skiing velocities along a measured track. These can be used to calculate the propulsive power output. Collected real-time positioning data from a cross-country sprint skiing race were used to estimate the propulsive power by applying a power balance model. Analyses were made for the time-trial and the final for one female and one male skier. The average propulsive power over the whole race times were 311 and 296 W during the time trial and 400 and 386 W during the final, for the female and male skier, respectively. Compared to the average propulsive power over the whole race, the average active propulsive phases were calculated as 33 and 44% higher in the time trials and 36 and 37% higher in the finals for the female and male, respectively. The current study presents a novel approach to use real-time positioning data to estimate continuous propulsive power during cross-country sprint skiing, enabling in-depth analyses of power output and pacing strategies. 相似文献
114.
Previous studies have found that laboratory conditions influence sleep-waking behavior in older infants, children, and adults. The present study employed videotape recordings to monitor continuous 24-hr sleep-waking activity in 2- and 8-week-old infants before, during, and after 12 hr of polygraphic recordings. Sleep- and waking-state organization were affected by laboratory conditions. At both age levels, increased fussy-crying and decreased alertness occurred during the first 4 hr in the laboratory when they were video recorded only and during the first 4 hr that the leads were in place. Decreased fussy-crying and increased alertness were noted in the following periods, indicating adaptation. Latency to sleep was shorter, and drowsiness increased and active sleep decreased while the leads were in place. At 8 weeks, quiet sleep increased and active sleep decreased while the leads were in place. These data suggest that the unfamiliar laboratory conditions inherent in both observational and polygraphic studies are stressful and that time for adaptation is needed. 相似文献
115.
116.
Anders Lysne 《Scandinavian Journal of Educational Research》2013,57(3):149-165
Abstract Lysne, A. 1984. Grading of Students' Attainment: Purposes and Functions. Scandinavian Journal of Educational Research 28, 149‐165. The article discusses the complex problem of evaluation and grading of students' achievement. During the 1970's a strong movement against the traditional formal grading and use of marks came up in many countries in the western world. The basic problem under question has been what type of reference measures should be used in grading students' achievement — measures of individual potentials or comprehensive norms or standards for attainment of skills and knowledge? The answer to this question depends, of course, on the type of functions the grades are supposed to serve. For individual guidance, it might be sufficient to give information about progress in relation to personal potentials, but that type of evaluation and grading can certainly not be used for selective purposes. A number of factors and viewpoints have to be taken into consideration when new reforms of grading systems for our schools are under discussion and planning. 相似文献
117.
118.
Susanne Ebert Kathrin Lockl Sabine Weinert Yvonne Anders Katharina Kluczniok Hans-Günther Rossbach 《School Effectiveness & School Improvement》2013,24(2):138-154
Competency in society's lingua franca plays a major role in the emergence of social disparities within education. Therefore, the present longitudinal study investigates vocabulary development and its predictors in preschool years. We focus on whether internal (phonological working memory) and external variables (preschool and home learning environment) have different impacts depending on parental native language. The study considers 547 children from 97 German preschools. Children's vocabulary was assessed at the ages of 3, 4, and 5 years. Latent growth curve models show that non-native German language children are characterized by reduced vocabulary at first assessment and lower progress compared to monolingual peers. Phonological working memory has a strong impact on all children's initial vocabulary but also on vocabulary growth in those whose parents speak German as an additional language. The effects of preschool and home learning environment are comparatively smaller. 相似文献
119.
This study investigates staff members’ ideas and assumptions about visitors’ learning at science and technology centres. It also aims to explore in what ways their reasoning intersect with existing theories about learning within the field of science and technology centre research. The results of the study reveal that the staff members allude to learning processes differently by distinguishing organized from non‐organized learning, theoretical learning from practical hands‐on learning, and serious from non‐serious learning. According to most of the staff members, these also conclude with different learning outcomes. Further, a majority of the staff members state that they do not have any scientific knowledge about learning despite the fact that they work with the construction of new exhibitions. When discussing visitors’ learning, the staff members instead refer to personal experiences, professional experiences, professional education, and external references. When it comes to how they reason about the natural scientific content, nearly all express that they use references from the natural science community and researchers’ knowledge. The article moreover discusses in what ways a socio‐cultural approach may be used in order to understand how learning arises when visitors interact with exhibits. 相似文献
120.
Eriksen J Thilsted AH Marie R Lüscher CJ Nielsen LB Svendsen WE Szabo P Kristensen A 《Biomicrofluidics》2011,5(3):31101-311014
A method of in situ chromosome immobilisation and DNA extraction in a microfluidic polymer chip was presented. Light-induced local heating was used to induce poly(N-isopropylacrylamide) phase transition in order to create a hydrogel and embed a single chromosome such that it was immobilised. This was achieved with the use of a near-infrared laser focused on an absorption layer integrated in the polymer chip in close proximity to the microchannel. It was possible to proceed to DNA extraction while holding on the chromosome at an arbitrary location by introducing protease K into the microchannel. 相似文献