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Model Assuming (model + assuming)

Distribution by Scientific Domains

Mathematics and Statistics	50%

Selected Abstracts

Attachment styles, conflict styles and humour styles: interrelationships and associations with relationship satisfaction

EUROPEAN JOURNAL OF PERSONALITY, Issue 2 2008
Arnie Cann
Abstract Relationships among attachment styles, conflict styles and humour styles were examined in the context of romantic relationships. Each style was assumed to be based upon underlying assumptions about self and others, so relationships among the measures were predicted. A model assuming that the relationship of attachment styles to relationship satisfaction was partially mediated by the conflict styles and humour styles was tested. Overall, the predicted relationships among the three measures were supported. Conflict styles and humour styles reflecting attitudes about others were related to the avoidance attachment style, while those reflecting attitudes about the self were related to the anxiety attachment dimension. Conflict styles and humour styles were mediators of the association of attachment style with relationship satisfaction. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Incorporating gene functional annotations in detecting differential gene expression

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 3 2006
Wei Pan
Summary., The importance of incorporating existing biological knowledge, such as gene functional annotations in gene ontology, in analysing high throughput genomic and proteomic data is being increasingly recognized. In the context of detecting differential gene expression, however, the current practice of using gene annotations is limited primarily to validations. Here we take a direct approach to incorporating gene annotations into mixture models for analysis. First, in contrast with a standard mixture model assuming that each gene of the genome has the same distribution, we study stratified mixture models allowing genes with different annotations to have different distributions, such as prior probabilities. Second, rather than treating parameters in stratified mixture models independently, we propose a hierarchical model to take advantage of the hierarchical structure of most gene annotation systems, such as gene ontology. We consider a simplified implementation for the proof of concept. An application to a mouse microarray data set and a simulation study demonstrate the improvement of the two new approaches over the standard mixture model. [source]

Random-coefficients hidden-Markov Poisson regression models for inferring a competitor's promotion strategy

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 4 2007
Johannes Ledolter
Abstract In this paper we consider the case of a drug manufacturer who has physician-level information on the prescription volume for its own brand and its competitor, has complete physician-level data on its own free-sampling plan, but has only sparse data on the competitor's promotion strategy. We investigate whether one is able to predict the competitor's promotion strategy from such limited data. We treat the competitor's promotion as a latent (unobservable) event, and propose a hidden Markov model (HMM) to describe its progression over time. Analysis of actual and simulated data shows that the HMM improves our ability to infer the missing promotion event if promotions are serially correlated. A simpler model assuming that the probability of transition from one sampling state to the other is independent of the current state is adequate if the serial correlation among promotions is weak. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Dietary histidine affects lens protein turnover and synthesis of N-acetylhistidine in Atlantic salmon (Salmo salar L.) undergoing parr,smolt transformation

AQUACULTURE NUTRITION, Issue 5 2005
O. BRECK
Abstract This study was conducted to investigate protein synthesis rates and metabolism of histidine (His)-derivatives in lenses of Atlantic salmon (Salmo salar L.) of different dietary His background during parr,smolt transformation. Two populations of Atlantic salmon parr of equal origin were established in freshwater (FW), 3 months prior to transfer to seawater (SW). The populations were fed either a control diet (CD) containing 8.9 g kg,1 His or the same diet added crystalline His to a total level of 14.2 g kg,1 (HD). On the basis of these two populations, 14C His force-feeding studies were performed; in FW 3 weeks prior to sea transfer and in SW 6 weeks after transfer. The studies were conducted by force-feeding the respective diets enriched with 14C labelled His, with subsequent measurements of incorporation of 14C His into lens free amino acid pool, as well as into lens proteins and other free His pool fractions. The latter included the major lens imidazole N-acetylhistidine (NAH). Lens concentrations of His and NAH were clearly influenced by dietary His history, both in parr and smolt. The lens His and NAH concentrations in the CD population were considerably lower in SW than in FW, while in the HD group the His level was equal and the NAH level 50% higher in SW than in FW. Fractional synthesis rate for NAH, KS (NAH), in FW was 8.2 and 4.2 ,mol g,1 day,1 for fish in the CD and HD populations, respectively. The corresponding KS (NAH) values in SW were 5.1 and 33.0 ,mol g,1 day,1. Our data show that free His is rapidly converted to NAH in the lens, and that NAH seems to have a very high turnover, especially in salmon reared in SW. Fractional synthesis rate for lens proteins, KS (PROTEIN), ranged between 1.8 and 17.3% day,1 (182 and 2791 ,g g,1 day,1, respectively), and was generally higher in SW than in FW (P < 0.01). In SW, KS (PROTEIN) was highest in fish in the HD population (P < 0.05), whereas lens protein retention in the HD group was significantly lower than the CD group (P = 0.01). In a second model assuming that His from lens NAH is available for protein synthesis, calculated values of KS (PROTEIN) ranged between 0.17% day,1 (17.6 ,g g,1 day,1) and 0.48% day,1 (70.2 ,g g,1 day,1). Cataract scores recorded in the His populations at a later point (day 204), showed that the CD fish had significantly higher mean cataract scores than individuals in the HD population (P < 0.01), confirming that low levels of lens His and NAH are associated with cataract development. [source]