Home About us Contact
|
Home About us Contact | ||
|
|
||
Screening Models (screening + models)
Selected AbstractsGround Water Modeling Applications Using the Analytic Element MethodGROUND WATER, Issue 1 2006Randall J. Hunt Though powerful and easy to use, applications of the analytic element method are not as widespread as finite-difference or finite-element models due in part to their relative youth. Although reviews that focus primarily on the mathematical development of the method have appeared in the literature, a systematic review of applications of the method is not available. An overview of the general types of applications of analytic elements in ground water modeling is provided in this paper. While not fully encompassing, the applications described here cover areas where the method has been historically applied (regional, two-dimensional steady-state models, analyses of ground water,surface water interaction, quick analyses and screening models, wellhead protection studies) as well as more recent applications (grid sensitivity analyses, estimating effective conductivity and dispersion in highly heterogeneous systems). The review of applications also illustrates areas where more method development is needed (three-dimensional and transient simulations). [source] Market-Share Contracts with Asymmetric InformationJOURNAL OF ECONOMICS & MANAGEMENT STRATEGY, Issue 2 2009Adrian Majumdar In this paper, a dominant firm and competitive fringe supply substitute goods to a retailer who has private information about demand. We show that it is profitable for the dominant firm to condition payment on how much the retailer buys from the fringe (market-share contracts). The dominant firm thereby creates countervailing incentives for the retailer and, in some cases, is able to obtain the full-information outcome (unlike in standard screening models, where the agent earns an information rent in the high-demand state and output is distorted in the low-demand state). Our results have implications for fidelity rebates, all-units discounts, and competition policy. Although some crowding out of the fringe may occur when demand is low, we show that market-share contracts need not be harmful for welfare. [source] A combination of HbA1c, fasting glucose and BMI is effective in screening for individuals at risk of future type 2 diabetes: OGTT is not neededJOURNAL OF INTERNAL MEDICINE, Issue 3 2006M. NORBERG Abstract. Objective., To identify a screening model that predicts high risk of future type 2 diabetes and is useful in clinical practice. Design and methods., Incident case-referent study nested within a population-based health survey. We compared screening models with three risk criteria and calculated sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and attributable proportion. We used fasting plasma glucose (FPG) alone or with an oral glucose tolerance test (OGTT), glycosylated haemoglobin A (HbA1c) (normal range 3.6,5.3%), body mass index (BMI), triglycerides and family history of diabetes (FHD). Setting., Participants in a health survey at all primary care centres (n = 33 336) and subjects with diagnosed type 2 diabetes in primary and hospital care (n = 6088) in Umeå during 1989,2001. Subjects., Each of the 164 subjects who developed clinically diagnosed type 2 diabetes (median time to diagnosis of 5.4 years) and 304 sex- and age-matched referents without diabetes diagnosis. Results., Screening models with at least one criterion present had sensitivities of 0.90,0.96, specificities of 0.43,0.57 and PPVs of 8,9%. Combinations of the criteria, FPG , 6.1 mmol L,1 (capillary plasma), HbA1c , 4.7% and BMI , 27 in men and BMI , 30 in women, had sensitivities, specificities and PPVs of 0.66%, 0.93% and 32%, and 0.52%, 0.97% and 46% respectively. Using FHD as one of three risk criteria showed comparable results. Addition of triglycerides or OGTT did not improve the prediction. Conclusions., The combination of HbA1c, FPG and BMI are effective in screening for individuals at risk of future clinical diagnosis of type 2 diabetes. OGTT or FHD is not necessary. [source] Anticonvulsant and antiepileptic actions of 2-deoxy-D-glucose in epilepsy models,ANNALS OF NEUROLOGY, Issue 4 2009Carl E. Stafstrom MD Objective Conventional anticonvulsants reduce neuronal excitability through effects on ion channels and synaptic function. Anticonvulsant mechanisms of the ketogenic diet remain incompletely understood. Because carbohydrates are restricted in patients on the ketogenic diet, we evaluated the effects of limiting carbohydrate availability by reducing glycolysis using the glycolytic inhibitor 2-deoxy-D-glucose (2DG) in experimental models of seizures and epilepsy. Methods Acute anticonvulsant actions of 2DG were assessed in vitro in rat hippocampal slices perfused with 7.5mM [K+]o, 4-aminopyridine, or bicuculline, and in vivo against seizures evoked by 6Hz stimulation in mice, audiogenic stimulation in Fring's mice, and maximal electroshock and subcutaneous pentylenetetrazol (Metrazol) in rats. Chronic antiepileptic effects of 2DG were evaluated in rats kindled from olfactory bulb or perforant path. Results 2DG (10mM) reduced interictal epileptiform bursts induced by 7.5mM [K+]o, 4-aminopyridine, and bicuculline, and electrographic seizures induced by high [K+]o in CA3 of hippocampus. 2DG reduced seizures evoked by 6Hz stimulation in mice (effective dose [ED]50 = 79.7mg/kg) and audiogenic stimulation in Fring's mice (ED50 = 206.4mg/kg). 2DG exerted chronic antiepileptic action by increasing afterdischarge thresholds in perforant path (but not olfactory bulb) kindling and caused a twofold slowing in progression of kindled seizures at both stimulation sites. 2DG did not protect against maximal electroshock or Metrazol seizures. Interpretation The glycolytic inhibitor 2DG exerts acute anticonvulsant and chronic antiepileptic actions, and has a novel pattern of effectiveness in preclinical screening models. These results identify metabolic regulation as a potential therapeutic target for seizure suppression and modification of epileptogenesis. Ann Neurol 2009;65:435,448. [source] Victorian orthoptists' performance in the photo evaluation of diabetic retinopathyCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 8 2007Zoran Georgievski BAppSc(Orth)Hons Abstract Purpose:, The aim of this study was to investigate the effectiveness of orthoptists in detecting various grades of diabetic retinopathy (DR) and retinal pathology not directly associated with diabetes and to identify factors associated with best performance. Methods:, Forty-five orthoptists completed a survey comprising questions regarding their workplace experiences, plus a photo evaluation task with 36 digital fundus images. Results:, We found that orthoptists' overall performance in detecting the presence of abnormality in a series of DR images was high, the mean sensitivity being 86% and specificity 91%. The sensitivity was lower for images with minimal non-proliferative DR, but higher for those with mild,moderate and severe grades of DR. No factors were predictive of performance on the screening task. Conclusions:, Orthoptists performed extremely well, meeting the guidelines for DR screening recommended by National Health and Medical Research Council. The results indicate that orthoptists could potentially be used in DR screening models in Australia. [source] | ||||||||||