Stationary principles and potential functions for nonlinear networks

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.     

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

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.     

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

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.     

Local Dependence in an Operational CAT: Diagnosis and Implications

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.     

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

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...