排序方式: 共有63条查询结果,搜索用时 15 毫秒
41.
Using the theoretical framework of risk and resiliency, the study estimated the contribution of five school-related delinquencies (behaviour problems, schoolwork problems, out-of-school suspension, in-school suspension and grade retention) and seven extracurricular activities (arts, sports, clubs, tutoring, volunteering, religious involvement and scouts) on the report card grades of students. An adolescent sample (N?=?2070) from the US National Household Education Survey was examined. A three-step hierarchical multiple regression found that the protective effects of extracurricular activities remained predictive of better grades, even after controlling for the risks of school-related delinquencies. The extracurricular activity of arts best predicted better grades, but the school-related delinquency of schoolwork problems best predicted worse grades. The discussion focuses on the implications of increasing resilience by promoting extracurricular involvement and combating the risk of school delinquencies. 相似文献
42.
Charles Aguiar Daniel Leite Daniel Pereira Goran Andonovski Igor Škrjanc 《Journal of The Franklin Institute》2021,358(2):1376-1402
Overhead cranes are widely used structures for lifting and conveying heavy loads. The development of feedback control systems for such equipment is important due to the large number of potential applications and advantages over manual operation concerning stability and robustness. This paper aims to represent the key nonlinear dynamics of crane systems by means of a state-space fuzzy model with compact rule-base structure. The fuzzy model is useful to assist the design of a fuzzy controller based on the concept of parallel compensation. A well-posed conservative linear-matrix-inequality (LMI) feasibility problem is formulated so that a solution guarantees closed-loop Lyapunov stability, bounded control inputs, quick positioning of the supporting cart, and suppression of load oscillations and collisions. The fuzzy controller is composed by rules with linear control laws derived from local state-space models. The controller warrants asymptotic convergence of the states. Due to the nonlinear nature of the fuzzy model and controller, Jacobian linearization is avoided. The proposed fuzzy control approach for cranes has shown to be more effective and robust than an optimal quadratic controller, and able to move cargo smoothly and safely to a destination. Particularly, constrained and smoother control inputs avoid actuator saturation, and tend to increase its lifetime. Laboratory experiments using the LMI fuzzy controller and actual data validates the approach for cranes in actual scenario. 相似文献
43.
Cubranic Z Madzar Z Matijevic S Dvornik S Fisic E Tomulic V Kunisek J Laskarin G Kardum I Zaputovic L 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2012,22(2):225-236
Introduction:
This study aimed to assess whether heart fatty acid-binding protein (H-FABP) and glycogen phosphorylase isoenzyme BB (GPBB) could be used for the accurate diagnosis of acute myocardial infarction (AMI) in acute coronary syndrome (ACS) patients.Materials and methods:
The study included 108 ACS patients admitted to a coronary unit within 3 h after chest pain onset. AMI was distinguished from unstable angina (UA) using a classical cardiac troponin I (cTnI) assay. H-FABP and GPBB were measured by ELISA on admission (0 h) and at 3, 6, 12, and 24 h after admission; their accuracy to diagnose AMI was assessed using statistical methods.Results:
From 92 patients with ACS; 71 had AMI. H-FABP and GPBB had higher peak value after 3 h from admission than cTnI (P = 0.001). Both markers normalized at 24 h. The area under the receiver operating characteristic curves was significantly greater for both markers in AMI patients than in UA patients at all time points tested, including admission (P < 0.001). At admission, the H-FABP (37%) and GPBB (40%) sensitivities were relatively low. They increased at 3 and 6 h after admission for both markers and decreased again after 24 h. It was 40% for H-FABP and approximately 2-times lower for GPBB (P < 0.01). In AMI patients, both biomarkers had similar specificities, positive- and negative-predictive values, positive and negative likelihood ratios, and risk ratios for AIM.Conclusion:
H-FABP and GPBB can contribute to early AMI diagnosis and can distinguish AMI from UA. 相似文献44.
Damir Zubac Reid Reale Hrvoje Karnincic Anamaria Sivric Igor Jelaska 《European Journal of Sport Science》2018,18(7):920-929
Urine specific gravity (USG) is the most commonly reported biochemical marker used in research and applied settings to detect fluid deficits in athletes, including those participating in combat sports. Despite the popularity of its use, there has been a growing debate regarding the diagnostic accuracy and the applicability of USG in characterizing whole-body fluid status and fluctuations. Moreover, recent investigations report universally high prevalence of hypohydration (~90%) via USG assessment in combat sport athletes, often in spite of stable body-mass. Given the widespread use in both research and practice, and its use in a regulatory sense as a ‘hydration test’ in combat sports as a means to detect dehydration at the time of weigh-in; understanding the limitations and applicability of USG assessment is of paramount importance. Inconsistencies in findings of USG readings, possibly as a consequence of diverse methodological research approaches and/or overlooked confounding factors, preclude a conclusive position stand within current combat sports research and practice. Thus the primary aim of this paper is to critically review the literature regarding USG assessment of hydration status in combat sports research and practice. When taken on balance, the existing literature suggests: the use of laboratory derived benchmarks in applied settings, inconsistent sampling methodologies, the incomplete picture of how various confounding factors affect end-point readings, and the still poorly understood potential of renal adaptation to dehydration in combat athletes; make the utility of hydration assessment via USG measurement quite problematic, particularly when diet and training is not controlled. 相似文献
45.
This research is aimed to assist individual learners to construct knowledge in online learning through providing them with
customized supportive services. The services go beyond simply presenting course materials, but supply a diverse range of technological
facilities, tools and services to assist individual learners to progress in the learning process. In this paper, the theoretical
background for facilitating construction of knowledge by individual learners is built at the first, through the review of
constructivist theories for learning and the objectivist ones. Then, a general conceptual model to describe any number of
practices in learning and teaching online is built. It will be used to customize online learning environments to cater for
various different learning demands. The services to support the individual’s knowledge construction are identified based on
the relevant theoretical background. After that, software agents are proposed to customize the supportive services for individual
learners based on their particular learning characteristics. Next, the implementation of these services is investigated and
a system prototype is reported. Finally the preliminary research result and the further work are presented. 相似文献
46.
Igor G. Chervanev 《Higher Education in Europe》1990,15(4):55-63
The author describes the development of environmental education at Kharkov University in the USSR. The uniqueness of the main programme in general ecodevelopmental education is that its basic disciplinary affiliation is geography, a deliberate choice made by the university authorities’ which the author amply justifies. In the process of explaining this choice, he presents eight theses with regard to the social demand for ecologists and the ecologization of education and what he believes to be the three principal bases for general environmental education at the university level. 相似文献
47.
We use the principle of minimum cross entropy (MCE) to build a non-parametric adaptive algorithm for smoothing the log-transformed periodogram, and construct an optimal estimate for the spectral density function of a process. We show that this estimate minimizes the cross-entropy with the log-transformed spectral density function of the process. The method is non-parametric and performs very well for the case of processes having rapidly changing spectra that exhibits a variable order of smoothness. The algorithm is locally based on linearly approximating the information present in the process, and uses this approximation to allow the bandwidth of the spectral window in the smoothed log-periodogram to vary. We extend the algorithm empirically for better application to processes having mixed, narrow-band spectra. Comparisons with other currently used procedures are performed through the means of simulated examples. 相似文献
48.
Educational theorists ranging from Ivan Illich to Jan Masschelein and Maarten Simons have described institutionalized schooling as a modernized, secular church, full of rituals, sacraments, and various incantations. For them, the function of the teacher as priest and schooling as baptism is highly problematic, separating education from the common world. As such, the educational theology of the school needs to be suspended in order for educational life to take on new meaning beyond the sacraments of learning. To further this line of inquiry, we turn to the work of Giorgio Agamben on the oath and its originary function of guaranteeing the truthfulness of language (‘sacrament of language’). Insofar as the oath is also operable in learning (in the voice of the teacher), we argue that such operability can be suspended through a dialogic practice called ‘community of infancy’, thereby making possible new, profane forms of educational life beyond baptism. 相似文献
49.
Educational Studies in Mathematics - This article presents a research apparatus for investigating and making sense of stories that emerge from feedback that mathematicians provide on... 相似文献
50.
Nelson Cowan Lara D. Nugent Emily M. Elliott Igor Ponomarev & J. Scott Saults 《Child development》1999,70(5):1082-1097
In previous studies of memory span, participants have attended to the stimuli while they were presented, and therefore have had the opportunity to use a variety of mnemonic strategies. In the main portion of the present study, participants (first- and fourth-grade children, and adults; 24 per age group) carried out a visual task while hearing lists of spoken digits and received a post-list digit recall cue only occasionally, for some lists. Under these conditions, list information presumably must be extracted from a passively held store such as auditory sensory memory. The results suggest that each individual has a core memory capacity limit that can be observed clearly in circumstances in which it cannot be supplemented by mnemonic strategies, and that the capacity limit appears to increase with age during childhood. Other, attention-demanding processes also contribute to memory for attended lists. 相似文献