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1.
Willmott GR  Platt M  Lee GU 《Biomicrofluidics》2012,6(1):14103-1410315
Tunable pores (TPs) have been used for resistive pulse sensing of 1 μm superparamagnetic beads, both dispersed and within a magnetic field. Upon application of this field, magnetic supraparticle structures (SPSs) were observed. Onset of aggregation was most effectively indicated by an increase in the mean event magnitude, with data collected using an automated thresholding method. Simulations enabled discrimination between resistive pulses caused by dimers and individual particles. Distinct but time-correlated peaks were often observed, suggesting that SPSs became separated in pressure-driven flow focused at the pore constriction. The distinct properties of magnetophoretic and pressure-driven transport mechanisms can explain variations in the event rate when particles move through an asymmetric pore in either direction, with or without a magnetic field applied. Use of TPs for resistive pulse sensing holds potential for efficient, versatile analysis and measurement of nano- and microparticles, while magnetic beads and particle aggregation play important roles in many prospective biosensing applications.  相似文献   
2.
This research analyzed both engineering and nontechnical issues involved in the use of Induction Loop Amplification (ILA) devices in auditoriums or large gathering places for hard-of-hearing individuals. A variety of parameters need to be taken into account to determine an optimal shape/configuration for the ILA device. In many cases, an optimal configuration is different from those proposed for classroom use (Ross, 1969; Hodgson, 1986; Clevenger, 1992). Experimental results were obtained for a double-loop configuration in such a setting (a university gymnasium/auditorium in this case). The results demonstrate that a double-loop configuration is a viable possibility for auditorium use. Several variables using this configuration were examined, and experimentation was done. Various implications, including consequent nontechnical issues specific to this application, are discussed as well. Technical and nontechnical aspects of the ILA configuration need to be examined together when designing an optimal system.  相似文献   
3.
Children tend to extend object names on the basis of sameness of shape, rather than size, color, or material-a tendency that has been dubbed the "shape bias." Is the shape bias the result of well-learned associations between words and objects? Or does it exist because of a general belief that shape is a good indicator of object category membership? The present three studies addressed this debate by exploring whether the shape bias is specific to naming. In Study 1, 3-year-olds showed the shape bias both when asked to extend a novel name and when asked to select an object of the same kind as a target object. Study 2 found the same shape bias when children were asked to generalize properties relevant to category membership. Study 3 replicated the findings from Study 1 with 2-year-olds. These findings suggest that the shape bias derives from children's beliefs about object kinds and is not the product of associative learning.  相似文献   
4.
Tensiomyography has been suggested as an indirect marker of muscle stiffness, which is associated with strength/power performance. Therefore, it is reasonable to suggest that tensiomyography parameters could be associated with power-related motor tasks. The purpose of this study was to investigate the association between tensiomyography parameters (from rectus and biceps femoris) and jumping and sprinting abilities in elite soccer players. In addition, we used tensiomyography parameters to compare the lateral symmetry between dominant and non-dominant legs. Twenty elite soccer players (age: 23.3 ± 4.8 years; height: 183.5 ± 6.6 cm; weight: 77.8 ± 7.5 kg) volunteered to participate in the study. Significant moderate negative correlations between biceps femoris displacement and contact time (r = –0.5, p = 0.03), rectus femoris displacement and contact time (r = –0.51, p = 0.02), and a significant moderate correlation between biceps femoris displacement and reactive strength index (r = 0.5, p = 0.03) were found. There were no correlations between tensiomyography parameters and power-related motor tasks. In addition, no differences in tensiomyography parameters between dominant and non-dominant legs were found. Our data suggest that tensiomyography parameters are not associated with power-related motor tasks performance in elite soccer players.  相似文献   
5.
We investigated whether heart rate (HR)-derived parameters are accurate performance predictors in endurance recreational runners. One hundred thirty recreational athletes completed an incremental running test (4´running + 1´rest). After each stage, we recorded HR, % of maximum HR (%HRmax), and blood lactate. We also assessed HR after each recovery period, and calculated lactate and HR recovery thresholds and HR deflection point. We tested these parameters for associations with running performance, as measured by peak treadmill speed (PTS) and personal best International Association of Athletics Federations (IAAF) score. The %HRmax at 14.5 km·h?1 correlated with PTS (r = ?0.92), and IAAF score (rho = ?0.80). The magnitudes of the correlations of lactate-related parameters with PTS (|r| = 0.84 to 0.86) or IAAF score (|rho| = 0.70 to 0.77) in absolute values were slightly lower. The correlations detected between other HR-derived parameters and running performance were weaker (|r or rho| = 0.24 to 0.70). Regression models identified %HRmax at 14.5 km·h?1 as the strongest predictor of both PTS (β = ?0.72) and IAAF score (β = ?0.72). Consequently, tests based on %HRmax may provide a non-invasive and inexpensive alternate method for predicting the performance of these athletes.  相似文献   
6.
In this paper we estimate the effect of class attendance on exam performance by implementing a policy in three large economics classes that required students scoring below the median on the midterm exam to attend class. This policy generated a large discontinuity in the rate of post-midterm attendance at the median of the midterm score. We estimate that near the policy threshold, the post-midterm attendance rate was 36 percentage points higher for those students facing compulsory attendance. The discontinuous attendance policy is also associated with a significant difference in performance on the final exam. We estimate that a 10 percentage point increase in a student's overall attendance rate results in a 0.17 standard deviation increase in the final exam score without adversely affecting performance on other classes taken concurrently.  相似文献   
7.
This study examined the effect of (a) high- and low-level questions and (b) reading the text before the questions asked on performance, delayed text recall, and deep text comprehension, as well as on specific text-inspection patterns. Participants were 37 undergraduate students who answered either high- or low-level questions using the software Read&Answer to read and answer questions on the computer screen. Additionally, half of the sample read first a text and then answered the questions (reading-first condition), whereas the other half answered the questions without having read the text in advance (no-reading-first condition). All participants had the text available to search for the answer. Results indicated that high-level questions facilitated deep comprehension but not immediate performance or delayed recall of text, independently of the reading condition, and that high- and low-level questions differentially affected text-inspection patterns.  相似文献   
8.
In two experiments, we investigated emergent conditional relations in pigeons using a symbolic matching-to-sample task with temporal stimuli as the samples and hues as the comparisons. Both experiments comprised three phases. In Phase I, pigeons learned to choose a red keylight (R) but not a green keylight (G) after a 1-s signal. They also learned to choose G but not R after a 4-s signal. In Phase II, correct responding consisted of choosing a blue keylight (B) after a 4-s signal and a yellow keylight (Y) after a 16-s signal. Comparisons G and B were both related to the same 4-s sample, whereas comparisons R and Y had no common sample. In Phase III, R and G were presented as samples, and B and Y were presented as the comparisons. The choice of B was correct following G, and the choice of Y was correct following R. If a relation between comparisons that shared a common sample were to emerge, then responding to B given G would be more likely than responding to Y given R. The results were generally consistent with this prediction, suggesting, for the first time in pigeons, the emergence of novel relations that involve temporal stimuli as nodal samples.  相似文献   
9.
论教师职业的专业化   总被引:18,自引:0,他引:18  
教师专业化是社会分化与职业分化的产物。本文首先论述了专门职业的概念,并归纳出专门职业的六大特征,即专业知识和技能、职业道德、长期的专门培养、进修制度、自主权、组织权。进而以此审视教师职业,提出教师职业是“从不成熟走向成熟的专门职业”,在教师专业化发展过程中,也需进一步加强与完善职业基本标推、专门职业观念等。  相似文献   
10.
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