排序方式： 共有32条查询结果，搜索用时 218 毫秒
1.
Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do explanations made by experts from different biology subdisciplines at a university support the validity of this model? Guided by the modeling framework of R. S. Justi and J. K. Gilbert, the validity of an initial model was tested by asking seven biologists to explain a molecular mechanism of their choice. Data were collected from interviews, artifacts, and drawings, and then subjected to thematic analysis. We found that biologists explained the specific activities and organization of entities of the mechanism. In addition, they contextualized explanations according to their biological and social significance; integrated explanations with methods, instruments, and measurements; and used analogies and narrated stories. The derived methods, analogies, context, and how themes informed the development of our final MACH model of mechanistic explanations. Future research will test the potential of the MACH model as a guiding framework for instruction to enhance the quality of student explanations. 相似文献
2.
Yuan-feng DUAN Ru ZHANG Yang ZHAO Siu-wing OR Ke-qing FAN Zhi-feng TANG 《浙江大学学报(A卷英文版)》2011,12(12):895-901
Steel structures are widely used in railway infrastructures. Their stress state is the most important determinant of the safety
of these structures. The elasto-magnetic (EM) sensor is the most promising for stress monitoring of in-service steel structures.
Nevertheless, the necessity of magnetic excitation to saturation due to the use of a secondary coil for signal detection,
keeps from its engineering application. In this paper, a smart elasto-magneto-electric (EME) sensor using magneto-electric
(ME) sensing units to take the place of the secondary coil has been exploited for the first time. The ME sensing unit is made
of ME laminated composites, which has an ultrahigh ME voltage coefficient and can measure the magnetic induction simply and
precisely. Theoretical analysis and characterization experiments firstly conducted on the ME laminated composites showed that
the ME sensing units can be applied in the EM sensor for improved performance in stress monitoring. A tension test of a steel
bar was carried out to characterize our smart EME sensor and the results showed high accuracy and sensitivity. The present
smart EME sensor is a promising tool for stress monitoring of steel structures in railway and other civil infrastructures. 相似文献
3.
4.
5.
The primary purpose of this exploratory field study was to examine the use of cognitive behavioural strategies by highly skilled orienteers prior to and during competition. A secondary purpose of the study was to investigate whether differences in the level of qualification in orienteering is related to state anxiety. The subjects were divided into three classes with respect to their international and national records. The first two classes (A and B) were composed of international and national level athletes. The third class (C) included orienteers with unknown international records. Examination of the use of behavioural cognitive strategies during competition indicated that all orienteers reported a moderate use of mental imagery, above moderate use of inner talk and a focus of attention on present action rather than past or future. The other major findings were that prior to competition, superior orienteers reported use of higher self‐efficacy, more positive outcome expectations and more task demand orientation than their less successful counterparts. Top orienteers coped more successfully with pre‐competition anxiety by lowering their anxiety to a more moderate level prior to the actual performance. 相似文献
6.
The growing ubiquity of mobile telephony able to send e-mail raises new questions, and renews old issues, about the effect of the medium on a message. This article reports experimental results testing effects of user- and medium-generated cues on perceptions of message senders. Grounded in warranting theory, we assess the interaction of low- and high-warrant cues on perceptions of the sender's professionalism, hypothesizing senders of grammatically accurate messages are perceived as more credible. However, we also hypothesize an interaction between grammatical accuracy and the system-generated high-warrant cues from the mobile device used to send the message. Responses from 111 students assessing the credibility of an e-mail sender indicate that, although a message's user-generated content (grammatically accurate vs. erred) influences receiver's perceptions, negative attributions are attenuated by cues reflecting the transmission medium (i.e., a message's mobile signature block). Findings offer theoretical implications for warranting theory. Additionally, results suggest practitioners need to craft a message and indicate the transmission medium strategically to mitigate any impacts on attributions of professionalism to message receivers. 相似文献
7.
Individuals frequently engage in self-presentation via social media and can subsequently receive various simple communicative cues (paralinguistic digital affordances; PDAs) from which they may determine the success of their self-presentation, including Likes and Upvotes. Previous research has found these communicatively abstract one-click cues are interpreted idiosyncratically when received, but the quantity received matters to users in determining whether a post is “successful.” The present work probes explanatory mechanisms behind the use of PDA responses as a metric of self-presentational success, deriving hypotheses from social comparison theory, social penetration theory, and expectancy violations theory. Results from a survey (N = 255) reveal that social comparison and communicative reciprocity provide explanatory power regarding the threshold of Likes and Reactions to a Facebook post needed to consider a post successful. 相似文献
8.
Alejandro?BellogínEmail authorView author&#;s OrcID profile Pablo?Castells Iván?Cantador 《Information Retrieval》2017,20(6):606-634
There is an increasing consensus in the Recommender Systems community that the dominant error-based evaluation metrics are insufficient, and mostly inadequate, to properly assess the practical effectiveness of recommendations. Seeking to evaluate recommendation rankings—which largely determine the effective accuracy in matching user needs—rather than predicted rating values, Information Retrieval metrics have started to be applied for the evaluation of recommender systems. In this paper we analyse the main issues and potential divergences in the application of Information Retrieval methodologies to recommender system evaluation, and provide a systematic characterisation of experimental design alternatives for this adaptation. We lay out an experimental configuration framework upon which we identify and analyse specific statistical biases arising in the adaptation of Information Retrieval metrics to recommendation tasks, namely sparsity and popularity biases. These biases considerably distort the empirical measurements, hindering the interpretation and comparison of results across experiments. We develop a formal characterisation and analysis of the biases upon which we analyse their causes and main factors, as well as their impact on evaluation metrics under different experimental configurations, illustrating the theoretical findings with empirical evidence. We propose two experimental design approaches that effectively neutralise such biases to a large extent. We report experiments validating our proposed experimental variants, and comparing them to alternative approaches and metrics that have been defined in the literature with similar or related purposes. 相似文献
9.
10.
Michael C. Zourdos Caleb D. Bazyler Edward Jo Andy V. Khamoui Bong-Sup Park Sang-Rok Lee 《Research quarterly for exercise and sport》2017,88(1):114-119
Purpose: The purpose of this investigation was to examine the effects of a submaximal running warm-up on running performance in male endurance athletes (n = 16, Mage = 21 ± 2 years, MVO2max = 69.3 ± 5.1 mL/kg/min). Method: Endurance performance was determined by a 30-min distance trial after control and submaximal running warm-up conditions in a randomized crossover fashion. The warm-up began with 5 min of quiet sitting, followed by 6 min of submaximal running split into 2-min intervals at speeds corresponding to 45%, 55%, and 65% maximal oxygen consumption (VO2max). A 2-min walk at 3.2 km/hr concluded the 13-min warm-up protocol. For the control condition, participants sat quietly for 13 min. VO2 and heart rate (HR) were determined at Minutes 0, 5, and 13 of the pre-exercise protocol in each condition. Results: At the end of 13 min prior to the distance trial, mean VO2 (warm-up = 14.1 ± 2.2 mL/kg/min vs. control = 5.5 ± 1.7 mL/kg/min) and mean HR (warm-up = 105 ± 11 bpm vs. control = 67 ± 11 bpm) were statistically greater (p < .001) in the warm-up condition compared with the control condition. The distance run did not statistically differ (p = .37) between the warm-up (7.8 ± 0.5 km) and control (7.7 ± 0.6 km) conditions; however, effect size calculation revealed a small effect (d = 0.2) in favor of the warm-up condition. Thus, the warm-up employed may have important and practical implications to determine placing among high-level athletes in close races. Conclusions: These findings suggest a submaximal running warm-up may have a small but critical effect on a 30-min distance trial in competitive endurance athletes. Further, the warm-up elicited increases in physiological variables VO2 and HR prior to performance; thus, a submaximal specific warm-up should warrant consideration. 相似文献