Home About us Contact
|
Home About us Contact | ||
|
|
||
One Model (one + model)
Selected AbstractsOrgans/Systems Potentially Involved In One Model Of Programmed Hypertension In SheepCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2001Miodrag Dodic SUMMARY 1. When pregnant ewes and their fetuses are exposed to the synthetic glucocorticoid dexamethasone for 2 days early in pregnancy (days 26,28; term 145,150 days), female offspring have increased blood pressure relative to a control group. In one series, this was shown to be due to increased cardiac output, concomitant with a reset mean arterial pressure/heart rate reflex. The first group of such animals had, by the age of 7 years, left ventricular hypertrophy and reduced cardiac functional capacity. 2. The elevation in blood pressure is not maintained by any change in the peripheral renin,angiotensin system (RAS). 3. There is, however, preliminary evidence that some aspects of local RAS (particularly in the kidney and brain) could have participated in the ,programming' event. The levels of mRNA for angiotensin II receptors (AT1, AT2) and angiotensinogen are increased in the kidney of such dexamethasone-treated fetuses in late gestation (130 days), some 100 days after steroid treatment. Similar increases in AT1 mRNA in the medulla oblongata of the fetal brain and large increases of mRNA for angiotensinogen occur in the hypothalamus. 4. These findings, together with evidence from the literature, suggest that both the kidney and parts of the brain are affected by events that also ,program' high blood pressure in the offspring of animals in which the intra-uterine environment has been perturbed at some stage. [source] Physiologically correct animation of the heartCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008Kyoungju Park Abstract Physiologically correct animation of the heart should incorporate non-homogeneous and nonlinear motions of the heart. Therefore, we introduce a methodology that estimates deformations from volume images and utilizes them for animation. Since volume images are acquired at regular slicing intervals, they miss information between slices and recover deformation on the slices. Therefore, the estimated finite element models (FEMs) result in coarse meshes with chunk elements the sizes of which depend on the slice intervals. Thus, we introduce a method of generating a detailed model using implicit surfaces and transferring a deformation from a FEM to implicit surfaces. An implicit surface heart model is reconstructed using contour data points and then cross-parameterized to the heart FEM, the time-varying deformation of which has been estimated by tracking the insights of the heart wall. The implicit surface heart models are composed of four heart walls that are blended into one model. A correspondence map between the source and the target meshes is made using the template fitting method. Deformation coupling transfers the deformation of a coarse heart FEM model to a detailed implicit model by factorizing linear equations. We demonstrate the system and show the resulting deformation of an implicit heart model. Copyright © 2008 John Wiley & Sons, Ltd. [source] Reserved Strength of Reinforced Concrete Buildings with Masonry WallsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2005Nasreddin S. El Mezaini In this building, damage was limited to some cracks in the walls near the targeted zone. Other parts of the building remained intact. The building was analyzed using two different models. In one model, masonry walls were treated as nonstructural elements represented by applied loads. In the other model, walls were represented by membrane elements connected to concrete frames by link elements. Analysis was carried out for two cases, before and after damage. The study revealed that such buildings possess potential reserved strength. They have the ability to change their designated load path. The role of masonry walls is emphasized. In this case, masonry walls worked as a backup system that prevented major collapse of the building. It is estimated that, under normal conditions, masonry walls increase the building strength by 48%. [source] A comparison of concurrent programming and cooperative multithreadingCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2003Aaron W. Keen Abstract This paper presents a comparison of the cooperative multithreading model with the general concurrent programming model. It focuses on the execution time performance of a range of standard concurrent programming applications. The overall results are mixed. In some cases, programs written in the cooperative multithreading model outperform those written in the general concurrent programming model. The contributions of this paper are twofold. First, it presents a thorough analysis of the performances of applications in the different models, i.e. to explain the criteria that determine when a program in one model will outperform an equivalent program in the other. Second, it examines the tradeoffs in writing programs in the different programming styles. In some cases, better performance comes at the cost of more complicated code. Copyright © 2003 John Wiley & Sons, Ltd. [source] Differences in spatial predictions among species distribution modeling methods vary with species traits and environmental predictorsECOGRAPHY, Issue 6 2009Alexandra D. Syphard Prediction maps produced by species distribution models (SDMs) influence decision-making in resource management or designation of land in conservation planning. Many studies have compared the prediction accuracy of different SDM modeling methods, but few have quantified the similarity among prediction maps. There has also been little systematic exploration of how the relative importance of different predictor variables varies among model types and affects map similarity. Our objective was to expand the evaluation of SDM performance for 45 plant species in southern California to better understand how map predictions vary among model types, and to explain what factors may affect spatial correspondence, including the selection and relative importance of different environmental variables. Four types of models were tested. Correlation among maps was highest between generalized linear models (GLMs) and generalized additive models (GAMs) and lowest between classification trees and GAMs or GLMs. Correlation between Random Forests (RFs) and GAMs was the same as between RFs and classification trees. Spatial correspondence among maps was influenced the most by model prediction accuracy (AUC) and species prevalence; map correspondence was highest when accuracy was high and prevalence was intermediate (average prevalence for all species was 0.124). Species functional type and the selection of climate variables also influenced map correspondence. For most (but not all) species, climate variables were more important than terrain or soil in predicting their distributions. Environmental variable selection varied according to modeling method, but the largest differences were between RFs and GLMs or GAMs. Although prediction accuracy was equal for GLMs, GAMs, and RFs, the differences in spatial predictions suggest that it may be important to evaluate the results of more than one model to estimate the range of spatial uncertainty before making planning decisions based on map outputs. This may be particularly important if models have low accuracy or if species prevalence is not intermediate. [source] THE COMBINED EFFECT OF DONATION PRICE AND ADMINISTRATIVE INEFFICIENCY ON DONATIONS TO US NONPROFIT ORGANIZATIONSFINANCIAL ACCOUNTABILITY & MANAGEMENT, Issue 1 2009Fred A. Jacobs We examine the effects that two accounting measures of nonprofit organization (NPO) inefficiency, administrative inefficiency and donation price, have on donations to US NPOs using a better-specified model and industry-specific samples. Although numerous studies examine the effect that donation price has on donations (e.g., Marudas and Jacobs, 2006; Marudas, 2004; Khanna and Sandler, 2000; and Tinkelman, 1999), only three studies examine the effect of administrative inefficiency on donations (Tinkelman and Mankaney, 2007; Frumkin and Kim, 2001; and Greenlee and Brown, 1999). However, none of these studies tests donation price and administrative inefficiency in one model and only two test industry-specific samples of NPOs. We find that misspecifying the model by including only one of these two inefficiency measures creates substantial bias and the effect of administrative inefficiency on donations varies substantially across industries. Administrative inefficiency has a significantly negative effect on donations to NPOs in the full sample and the philanthropy sample, but no significant effect on donations to NPOs in the arts, education, health, or human services samples. Furthermore, donation price has a significantly negative effect on donations to NPOs in the full sample and the education, health and human services samples, but not in the arts or philanthropy samples. Results are also reported for the other variables in the model , government support, program service revenue, fundraising and organizational age, wealth and size. [source] ALL THIS HAPPENED, MORE OR LESS: WHAT A NOVELIST MADE OF THE BOMBING OF DRESDEN,HISTORY AND THEORY, Issue 2 2009ANN RIGNEY ABSTRACT Kurt Vonnegut's novel Slaughterhouse-Five (1969) was a popular and critical success when it first appeared, and has had a notable impact on popular perceptions of "the bombing of Dresden," although it has been criticized by historians because of its inaccuracy. This article analyzes the novel's quirky, comic style and its generic mixture of science fiction and testimony, showing how Vonnegut consistently used ingenuous understatement as a way of imaginatively engaging his readers with the horrors of war. The article argues that the text's aesthetics are closer to those of graphic novels than of realist narratives and that, accordingly, we can understand its cultural impact only by approaching it as a highly artificial linguistic performance with present-day appeal and contemporary relevance, and not merely by measuring the degree to which it gives a full and accurate mimesis of past events. The article uses the case of Vonnegut to advance a more general argument that builds on recent work in cultural memory studies: in order to understand the role that literature plays in shaping our understanding of history, it needs to be analyzed in its own terms and not as a mere derivative of historiography according to a "one model fits all" approach. Furthermore, we need to shift the emphasis from products to processes by considering both artistic and historiographical practices as agents in the ongoing circulation across different cultural domains of stories about the past. Theoretical reflection should account for the fact that historiography and the various arts play distinct roles in this cultural dynamics, and while they compete with one another, they also converge, bounce off one another, influence one another, and continuously beg to be different. [source] Modeling the Effects of Reactor Inlet Configuration on Isothermal CVI Process of C/SiC CompositesINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2007Xi Wei Two comparative models were proposed to simulate the effects of the reactor configuration on the isothermal chemical vapor infiltration (ICVI) process of C/SiC composites. The difference in the two models is that there is an expansion zone near the reactor inlet in one model while no expansion zone exists in another model. Calculation results show that the existence of the expansion zone has rather negligible effects on the ICVI process. It is accordingly suggested that the simplification of the reactor configuration by neglecting the expansion zone of the reactor is reasonable and acceptable for the ICVI process of C/SiC composites. [source] Do consumption expenditures depend on the household's relative position in the income distribution?INTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 1 2002Mohamed Abdel-Ghany Abstract Even though the permanent income and relative income hypotheses have been introduced in past research to explain consumer behaviour, no previous attempt was undertaken to integrate them in one model. In this article, the hypotheses were synthesized into a single model. The model was empirically tested using data from the 1996 Canadian Family Expenditure Survey. The results indicate that household consumption behaviour is generally explained by both hypotheses when integrated into one model, contrary to previously treating them as mutually exclusive hypotheses. [source] Sensitivity analysis for incomplete contingency tables: the Slovenian plebiscite caseJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2001Geert Molenberghs Classical inferential procedures induce conclusions from a set of data to a population of interest, accounting for the imprecision resulting from the stochastic component of the model. Less attention is devoted to the uncertainty arising from (unplanned) incompleteness in the data. Through the choice of an identifiable model for non-ignorable non-response, one narrows the possible data-generating mechanisms to the point where inference only suffers from imprecision. Some proposals have been made for assessing the sensitivity to these modelling assumptions; many are based on fitting several plausible but competing models. For example, we could assume that the missing data are missing at random in one model, and then fit an additional model where non-random missingness is assumed. On the basis of data from a Slovenian plebiscite, conducted in 1991, to prepare for independence, it is shown that such an ad hoc procedure may be misleading. We propose an approach which identifies and incorporates both sources of uncertainty in inference: imprecision due to finite sampling and ignorance due to incompleteness. A simple sensitivity analysis considers a finite set of plausible models. We take this idea one step further by considering more degrees of freedom than the data support. This produces sets of estimates (regions of ignorance) and sets of confidence regions (combined into regions of uncertainty). [source] Model dependence of transonic properties of accretion flows around black holesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2001Sandip K. Chakrabarti We analytically study how the behaviour of accretion flows changes when the flow model is varied. We study the transonic properties of the conical flow, a flow of constant height and a flow in vertical equilibrium, and show that all these models are basically identical, provided that the polytropic constant is suitably changed from one model to another. We show that this behaviour is extendible even when standing shocks are produced in the flow. The parameter space where shocks are produced remains roughly identical in all these models when the same transformation among the polytropic indices is used. We present applications of these findings. [source] A conceptual model of perceived customer value in e-commerce: A preliminary investigationPSYCHOLOGY & MARKETING, Issue 4 2003Zhan Chen This article presents an exploratory study of a conceptual model of perceived customer value in a business-to-consumer e-commerce setting. Key precursors of perceived customer value included in the model are valence of on-line shopping experience, perceived product quality, perceived risk, and product price. Relationships among these variables (as well as mediating variables) and their relationship to on-line shoppers' value perceptions are explored. The theoretical framework proposed in this work expands on previous efforts on perceived customer value by including new variables relevant to an e-commerce setting and by integrating several key variables into one model. The preliminary findings lead to several implications. © 2003 Wiley Periodicals, Inc. [source] A non-parametric approach to software reliabilityAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 1 2004Axel Gandy Abstract In this paper we present a new, non-parametric approach to software reliability. It is based on a multivariate counting process with additive intensity, incorporating covariates and including several projects in one model. Furthermore, we present ways to obtain failure data from the development of open source software. We analyse a data set from this source and consider several choices of covariates. We are able to observe a different impact of recently added and older source code onto the failure intensity. Copyright © 2004 John Wiley & Sons, Ltd. [source] Two Possible Mechanisms Underlying Nitrate Tolerance In Monkey Coronary ArteriesCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2001Tomoko Omura SUMMARY 1. Previous studies using isolated arteries have demonstrated cross-tolerance between nitric oxide (NO) donors such as nitroglycerin (NTG) and sodium nitroprusside (SNP). However, it remains unclear whether the vasorelaxing effect of atrial natriuretic peptide (ANP), an activator of particulate guanylate cyclase, is affected by treatment with NO donors. To investigate the cross-tolerance and interactions between NTG and ANP in coronary vasorelaxant responses, we used two models of monkey coronary arterial strips (Macaca fuscata). 2. In one model, which was induced by a 1 h treatment with 4.4 × 10,4 mol/L NTG followed by washout of the agent for 1 h, the vasorelaxing effects of subsequent NTG were markedly attenuated, whereas those of ANP and NO were not affected. These findings suggest that the development of NTG tolerance is associated with a biotransformation process from NTG to NO. In the other model, which did not include washout after exposure to 3 × 10,6 mol/L NTG, the vasorelaxant responses to 10,8 mol/L ANP (31.1±5.4 vs 5.1±2.1%, respectively; P < 0.001), 10,6 mol/L NO (61.5±2.4 vs 29.5±8.5%, respectively; P < 0.001) and 10,8 mol/L SNP (49.4±6.4 vs 8.0±2.0%, respectively; P < 0.001) were significantly attenuated. The concentration, response curve for 8-bromo-cGMP (8-Br-cGMP) was shifted to the right, whereas responses to papaverine and forskolin were unchanged. These findings suggest that an intracellular process that occurs after the synthesis of cGMP is responsible for this interaction. 3. As a mechanism of NTG tolerance, two possible processes may be impaired: (i) biotransformation from NTG to NO; and (ii) an intracellular process that occurs after the synthesis of cGMP. [source] Performance comparisons and attachment: An investigation of competitive responses in close relationshipsPERSONAL RELATIONSHIPS, Issue 3 2005ANTHONY SCINTA Two studies investigated whether affective responses to competitive performance situations are moderated by attachment style. In Study 1, participants (n= 115) imagined their reactions to a superior or inferior performance against their romantic partner or an acquaintance. Results showed that participants low in attachment avoidance, relative to those high in avoidance, indicated more positivity after an inferior performance (empathy effect) to their partners, and this finding held only in domains of high importance to the partner. In Study 2, participants (n= 53) imagined comparisons with their partner or a close friend. Low-avoidance participants, relative to high-avoidance participants, exhibited sympathy and empathy effects in comparisons involving their romantic partner but not those involving a friend. The findings are discussed in terms of one's model of other and perceived self,other separation, which are defined by avoidance but not anxiety. [source] | ||||||||||||||||