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51.
DBA/2J mice were exposed to a distinctive floor stimulus (CS+) and ethanol (2 g/kg) in a place conditioning paradigm. A different floor stimulus (CS?) was presented with saline. Mice injected just before or 30 min before CS exposure (Groups 0, ?30) showed conditioned place preference, whereas mice injected right after exposure to the CS (Group 5) displayed place aversion (Experiment 1). None of the other groups (?120, ?60, 15, 60) showed place conditioning. Handling and saline injection given just before or after CS exposure were unable to produce place conditioning (Experiment 2). However, there was a positive relationship between ethanol concentration (10% vs. 20%) and test performance, suggesting that peritoneal irritation influences place conditioning (Experiment 3). Overall, these findings support the suggestion that intraperitoneal injection of ethanol produces an initial short-duration aversive effect that is followed by a longer lasting positive motivational effect.  相似文献   
52.
This paper proposes a new sliding mode observer for fault reconstruction, applicable for a class of linear parameter varying (LPV) systems. Observer schemes for actuator and sensor fault reconstruction are presented. For the actuator fault reconstruction scheme, a virtual system comprising the system matrix and a fixed input distribution matrix is used for the design of the observer. The fixed input distribution matrix is instrumental in simplifying the synthesis procedure to create the observer gains to ensure a stable closed-loop reduced order sliding motion. The ‘output error injection signals’ from the observer are used as the basis for reconstructing the fault signals. For the sensor fault observer design, augmenting the LPV system with a filtered version of the faulty measurements allows the sensor fault reconstruction problem to be posed as an actuator fault reconstruction scenario. Simulation tests based on a high-fidelity nonlinear model of a transport aircraft have been used to demonstrate the proposed actuator and sensor FDI schemes. The simulation results show their efficacy.  相似文献   
53.
Higher education has seen increasing educational mobility as students finance themselves or get financial support from their families to study abroad (Shields Comp Educ Rev 57(4):609–636, 2013; Verbik and Lazanowski in World education news and reviews. http://www.wes.org/educators/pdf/StudentMobility.pdf, 2007). Another significant source of support, particularly for students in developing countries, is that from international aid scholarships. This research presents the reported experiences of 15 Tongan postgraduate scholars who successfully completed overseas postgraduate studies. The study focuses on the perceptions of qualifications and of scholars, as well as knowledge utilisation and knowledge resituation in and beyond the workplace. Knowledge utilisation, sometimes referred to as knowledge management, is how others support returnees’ to share and make use of their knowledge; while knowledge resituation is a personal and individual process in which knowledge gained in one context is tuned to and made use of in a new context (Eraut in Expertise development: the transition between school and work. Open Universiteit, Heerlen, pp 52–73, 2004a, Pedagogy and practice. Culture and identities. Sage, London, 2008; Franken 2012). Given the challenges the scholars faced, we advocate for a more explicit recognition of what knowledge and skills returning scholars bring home, and a more proactive and strategic use of these by their workplaces in particular.  相似文献   
54.
An important concern when planning research studies is to obtain maximum precision of an estimate of a treatment effect given a budget constraint. When research designs have a multilevel or hierarchical structure changes in sample size at different levels of the design will impact precision differently. Furthermore, there will typically be differential costs of enrolling additional units at different levels of the hierarchy. The optimal design problem in multilevel research studies involves determining the optimal sample size at each level of the design given specified design parameters and a specified marginal cost of recruitment at each level. The current work extends existing results by considering optimal design for (a) unbalanced random assignment designs and (b) regression discontinuity designs.  相似文献   
55.
Many schools are beginning to implement multi-tier response to intervention (RTI) models for the prevention of reading difficulties and to assist in the identification of students with learning disabilities (LD). The present study was part of our larger ongoing longitudinal RTI investigation within the Florida Learning Disabilities Center grant. This study used a longitudinal correlational design, conducted in 7 ethnically and socio-economically diverse schools. We observed reading instruction in 20 classrooms, examined response rates to kindergarten Tier 1 instruction, and predicted students' first grade reading performance based upon kindergarten growth and end of year reading performance (n = 203). Teachers followed an explicit core reading program and overall, classroom instruction was rated as effective. Results indicate that controlling for students' end of kindergarten reading, their growth across kindergarten on a variety of language and literacy measures suppressed predictions of first grade performance. Specifically, the steeper the students' trajectory to a satisfactory outcome, the less likely they were to demonstrate good performance in first grade. Implications for future research and RTI implementation are discussed.  相似文献   
56.
This study aimed to systematically assess the readiness of five countries – Brazil, the Former Yugoslav Republic of Macedonia, Malaysia, Saudi Arabia, and South Africa – to implement evidence-based child maltreatment prevention programs on a large scale. To this end, it applied a recently developed method called Readiness Assessment for the Prevention of Child Maltreatment based on two parallel 100-item instruments. The first measures the knowledge, attitudes, and beliefs concerning child maltreatment prevention of key informants; the second, completed by child maltreatment prevention experts using all available data in the country, produces a more objective assessment readiness. The instruments cover all of the main aspects of readiness including, for instance, availability of scientific data on the problem, legislation and policies, will to address the problem, and material resources. Key informant scores ranged from 31.2 (Brazil) to 45.8/100 (the Former Yugoslav Republic of Macedonia) and expert scores, from 35.2 (Brazil) to 56/100 (Malaysia). Major gaps identified in almost all countries included a lack of professionals with the skills, knowledge, and expertise to implement evidence-based child maltreatment programs and of institutions to train them; inadequate funding, infrastructure, and equipment; extreme rarity of outcome evaluations of prevention programs; and lack of national prevalence surveys of child maltreatment. In sum, the five countries are in a low to moderate state of readiness to implement evidence-based child maltreatment prevention programs on a large scale. Such an assessment of readiness – the first of its kind – allows gaps to be identified and then addressed to increase the likelihood of program success.  相似文献   
57.
58.
The effects of three routine classroom tasks upon heart rate reactivity were investigated with a sample of 30 typical fifth-grade children. Instructions for a mental arithmetic task, the mental arithmetic task itself, and silent reading were administered under standardized conditions, with a reward being offered for performance on the mental arithmetic task to enhance competition. Heart rate was individually monitored each second during these tasks, and data were collected on mental arithmetic performance and reading ability. Results indicated that some children showed large increases in their heart rates during the three tasks, and that these children should be considered as at-risk in terms of their cardiac health.  相似文献   
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This study examines the perceived impacts of electronic government or e-government adoption on U.S. cities. This research conducted a survey of Texas and Florida city managers in the fall of 2005 to find out their opinions on the impact of e-government on their city government. The results indicated that e-government is having a positive impact on management, stakeholder involvement, needs and collaboration, and procurement in American cities. There are, however, concerns over spam or unsolicited e-mail and the ability of e-government to reduce the level of staffing. The results of this study imply that, according to city managers' perceptions, e-government adoption in American city governments is positively viewed as having an impact on their organizations and communities.  相似文献   
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