Search results for "selection"
showing 10 items of 1940 documents
Investigating the association between cancer and the risk of dementia: Results from the Memento cohort
2021
International audience; IntroductionStudies on the association of cancer and risk of dementia are inconclusive due to result heterogeneity and concerns of survivor bias and unmeasured confounding.MethodsThis study uses data from the Memento cohort, a French multicenter cohort following persons with either mild or isolated cognitive complaints for a median of 5 years. Illness‐death models (IDMs) were used to estimate transition‐specific hazard ratios (HRs) and 95% confidence intervals (CIs) for incident cancer in relation to dementia from time since study entry.ResultsThe analytical sample (N = 2258) excluded 65 individuals without follow‐up information. At the end of follow‐up, 286 individu…
Selection bias during recruitment of elderly subjects from the general population for psychiatric interviews
1997
The aim of the present study was to determine and assess a possible selection bias in an epidemiologic investigation in the elderly. A stratified sample of 1305 probands aged 60-99 years was initially contacted by mail and then by telephone to obtain their consent to participate in a psychiatric interview. A liberal recruitment procedure led to interview participation of only 291 subjects. The proportion of younger, male, and married subjects participating in the study was greater than that of elderly, female, and single or widowed subjects. Subjects without a psychiatric lifetime diagnosis were more cooperative than those with a psychiatric disorder. The latter finding demonstrates the nee…
Gonadotropin Hormone Modulation of Testosterone, Immune Function, Performance, and Behavioral Trade‐Offs among Male Morphs of the Lizard Uta stansbur…
2008
Sexual selection predicts that trade-offs maintain trait variation in alternative reproductive strategies. Experiments often focus on testosterone (T), but the gonadotropins follicle-stimulating hormone and luteinizing hormone may provide a clearer understanding of the pleiotropic relationships among traits. We assess the activational role of gonadotropins on T and corticosterone regulation in traits expressed by polymorphic male side-blotched lizards Uta stansburiana. Gonadotropins are found to enhance and suppress multiple physiological, morphological, and behavioral traits independently, as well as indirectly via T, and we demonstrate selective trade-offs between reproduction and surviva…
Choline PET/CT Features to Predict Survival Outcome in High Risk Prostate Cancer Restaging: A Preliminary Machine-Learning Radiomics Study
2020
Background Radiomic features are increasingly utilized to evaluate tumor heterogeneity in PET imaging but to date its role has not been investigated for Cho-PET in prostate cancer. The potential application of radiomics features analysis using a machine-learning radiomics algorithm was evaluated to select 18F-Cho PET/CT imaging features to predict disease progression in PCa. Methods We retrospectively analyzed high-risk PCa patients who underwent restaging 18F-Cho PET/CT from November 2013 to May 2018. 18F-Cho PET/CT studies and related structures containing volumetric segmentations were imported in the "CGITA" toolbox to extract imaging features from each lesion. A Machine-learning model h…
Transient and Permanent Experience with Fatty Acids Changes Drosophila melanogaster Preference and Fitness
2013
Food and host-preference relies on genetic adaptation and sensory experience. In vertebrates, experience with food-related cues during early development can change adult preference. This is also true in holometabolous insects, which undergo a drastic nervous system remodelling during their complete metamorphosis, but remains uncertain in Drosophila melanogaster. We have conditioned D. melanogaster with oleic (C18:1) and stearic (C18:0) acids, two common dietary fatty acids, respectively preferred by larvae and adult. Wild-type individuals exposed either during a transient period of development-from embryo to adult-or more permanently-during one to ten generation cycles-were affected by such…
Weighted Least-Squares Likelihood Ratio Test for Branch Testing in Phylogenies Reconstructed from Distance Measures
2005
A variety of analytical methods is available for branch testing in distance-based phylogenies. However, these methods are rarely used, possibly because the estimation of some of their statistics, especially the covariances, is not always feasible. We show that these difficulties can be overcome if some simplifying assumptions are made, namely distance independence. The weighted least-squares likelihood ratio test (WLS-LRT) we propose is easy to perform, using only the distances and some of their associated variances. If no variances are known, the use of the Felsenstein F-test, also based on weighted least squares, is discussed. Using simulated data and a data set of 43 mammalian mitochondr…
New Challenges of Economic and Business Development – 2012 : Conference Proceedings (May 10 - 12, 2012, Riga, University of Latvia)
2012
Support for Conference Proceedings by ERAF Project "Support for the international cooperation projects and other international cooperation activities in research and technology at the University of Latvia" No. 2010/0202/2DP/2.1.1.2.0/10/APIA/VIAA/013
Minimising value-at-risk in a portfolio optimisation problem using a multi-objective genetic algorithm
2011
[EN] In this paper, we develop a general framework for market risk optimisation that focuses on VaR. The reason for this choice is the complexity and problems associated with risk return optimisation (non-convex and non-differential objective function). Our purpose is to obtain VaR efficient frontiers using a multi-objective genetic algorithm (GA) and to show the potential utility of the algorithm to obtain efficient portfolios when the risk measure does not allow calculating an optimal solution. Furthermore, we measure differences between VaR efficient frontiers and variance efficient frontiers in VaR-return space and we evaluate out-sample capacity of portfolios on both bullish and bearis…
Pure donation or hybrid donation crowdfunding
2019
PurposeDespite the growing research exploring the possibility and feasibility of financing socially oriented projects through crowdfunding, relatively little research examines which crowdfunding model is better to serve such purpose. The purpose of this paper is to offer novel insights to mitigate this research gap.Design/methodology/approachA unique data set collected from the largest Chinese crowdfunding platform is used to test the hypotheses. To solve the perceived self-selection problem, the propensity score matching method is adopted in this paper. Based on this approach, the results of similar prosocial campaigns in two different models (pure donation and hybrid donation) are compare…
A hybrid approach to international market selection: The case of impact investing organizations
2020
Abstract Social enterprises are hybrid organizations that concurrently pursue social and economic goals and hence are mid-way between conventional capitalistic firms and non-profit organizations. Many social enterprises are becoming international; delivering services across borders. With the objective of understanding the internationalization of these unconventional organizations, this paper examines their international market selection decision based on host countries’ macroeconomic conditions. Generally, we hypothesize that the international market selection decision of social enterprises is tied to their hybridity, an overarching characteristic that sets them apart from other types of or…