Stationary principles and potential functions for nonlinear networks     

L.O. Chua 《Journal of The Franklin Institute》1973,296(2):91-113

This paper presents a novel graph theoretic approach for deriving various stationary principles for single-element type nonlinear networks. The concepts of total content, co-content and hybrid content are generalized to that of total parametric content for resistive nonlinear networks containing multivalued elements. The results by Brayton and Moser on potential functions for complete m-ports are generalized to non-complete m-ports in terms of three pseudopotential functions; namely, the pseudo-content, pseudo- co-content and the pseudo-hybrid content. The precise criterion for which each of these pseudo-potential functions reduces to a legitimate potential function is shown to be the unique solvability of an implicit set of equations given explicitly in terms of standard topological matrices. Simple circuit theoretic sufficient conditions are given which require merely the positive-definiteness of the incremental resistance matrix of an auxiliary complete current-controlled p-port and the incremental conductance matrix of an auxiliary complete voltage-controlled q-port. These conditions also guarantee that a non-complete dynamic nonlinear network can be represented by a system of normal form differential equations in terms of a single mixed potential function.  相似文献   

Role of pump prime in the etiology of cardio-pulmonary bypass associated acidosis     

O. P. Sanjay  Kshma Kilpadi 《Indian journal of clinical biochemistry : IJCB》2002,17(1):42-44

The development of metabolic acidosis during cardio-pulmonary bypass (CPB) is a well recognized but poorly explained phenomenon. It has been hypothesized that it is purely a development after the delivery of pump prime. A retrospective study was conducted at our hospital on 68 patients who underwent elective coronary artery bypass grafting (CABG). Sampling of arterial blood was performed at three time intervals: (T₁) Baseline, prior to induction; (T₂) 5 minutes after initiation of CPB and prior to administration of cardioplegia solution; (T3) during rewarming prior to weaning the patient off CPB. Measurements of Na⁺, K⁺, Cl⁻, pH, pCO₂, HCO₃ ⁻, Base excess, Anion gap, Strong ion difference at each collection point were performed. Results were analyzed in a quantitative manner. On delivery of pump prime, all patients' developed metabolic acidosis. However, it is very important to distinguish the metabolic acidosis as their management varies. Anion gap has been found to be useful in managing peri-operative metabolic acidosis.  相似文献   

American post-conflict educational reform: From the Spanish American War to Iraq     

Thomas V. O’Brien 《History of education》2016,45(2):246-250

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Influence of reading attitude on reading achievement: A test of the temporal‐interaction model     

Rebecca S. Martínez  O. Tolga Aricak  Jeremy Jewell 《Psychology in the schools》2008,45(10):1010-1023

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Demographics and professional practices of school psychologists: A comparison of NASP members and non–NASP school psychologists by telephone survey     

Michael F. Lewis  Stephen D. Truscott  Martin A. Volker 《Psychology in the schools》2008,45(6):467-482

A national telephone survey was conducted to examine potential differences between National Association of School Psychologists (NASP) members and non–NASP member school psychologists. Identified schools were contacted by telephone and the researchers asked to speak with the school psychologist. A sample of 124 practicing school psychologists was obtained. Overall, 57.3% (n = 71) of respondents were NASP members, and 42.7% (n = 53) were not. In most respects, current results were similar to NASP‐member‐only surveys. Current results suggest that previous studies overestimated the proportion of NASP members among school psychologists and may have underestimated the total number of school‐based practitioners. Significant differences between NASP members and nonmembers were found in ethnicity, national certification, professional organization membership, and use of Curriculum Based Measurement. Results are discussed in the context of previous national surveys. © 2008 Wiley Periodicals, Inc.  相似文献   

How are the Perceptions of Learning Networks Shaped Among School Professionals and Headteachers at an Early Stage in their Introduction?     

Mark O’Brien  Tünde Varga-Atkins  Diana Burton  Anne Campbell  Anne Qualter 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2008,11(3):211-242

This paper draws on the findings of a research project funded by the Liverpool City of Learning consortium in the UK. The aim is to explore the process of introduction of ten authority wide learning networks, the impact these have on school professionals practice, the opportunities they offer for CPD and the extent to which they may impact on pupil learning. The research presented here draws on findings from a questionnaire distributed to school professionals and key issues emerging from their analysis point to the influence of national government agendas on school professionals’ interpretation of the purpose of the networks. They also point to the views of staff regarding the impact of the attainment agenda as well as the extent to which an increased emphasis on social inclusion and wider understandings of learning and achievement (which are less well represented by results-based performance monitoring) are having on their hopes for what Learning Networks might deliver. The expectations of staff of the opportunities offered by learning networks for long term professional development provide some interesting insights, and perhaps, some useful pointers as to how networks of this kind might develop in the future.  相似文献   

Local Dependence in an Operational CAT: Diagnosis and Implications     

Mary Pommerich  Daniel O. Segall 《Journal of Educational Measurement》2008,45(3):201-223

The accuracy of CAT scores can be negatively affected by local dependence if the CAT utilizes parameters that are misspecified due to the presence of local dependence and/or fails to control for local dependence in responses during the administration stage. This article evaluates the existence and effect of local dependence in a test of Mathematics Knowledge. Diagnostic tools were first used to evaluate the existence of local dependence in items that were calibrated under a 3PL model. A simulation study was then used to evaluate the effect of local dependence on the precision of examinee CAT scores when the 3PL model was used for selection and scoring. The diagnostic evaluation showed strong evidence for local dependence. The simulation suggested that local dependence in parameters had a minimal effect on CAT score precision, while local dependence in responses had a substantial effect on score precision, depending on the degree of local dependence present.  相似文献   

Psychology,market pressures,and pricing decisions in higher education: the case of the US private sector     

Cheslock  John J.  Riggs  Sam O. 《Higher Education》2021,81(4):757-774

Higher Education - We examine listed tuition and institutional aid practices within the US private sector, a sector where market pressures are relatively strong and consequently influence...  相似文献   

A follow-up power analysis of the statistical tests used in the Journal of Research in Science Teaching     

Thomas W. Woolley  George O. Dawson 《科学教学研究杂志》1983,20(7):673-681

It has been two decades since the first power analysis of a psychological journal and 10 years since the Journal of Research in Science Teaching made its contribution to this debate. One purpose of this article is to investigate what power-related changes, if any, have occurred in science education research over the past decade as a result of the earlier survey. In addition, previous recommendations are expanded and expounded upon within the context of more recent work in this area. The absence of any consistent mode of presenting statistical results, as well as little change with regard to power-related issues are reported. Guidelines for reporting the minimal amount of information demanded for clear and independent evaluation of research results by readers are also proposed.  相似文献   

Limits to growth,a challenge to higher education     

Dennis Meadows  Lewis Perelman 《Prospects》1977,7(1):33-43

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