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In this paper, we consider a statistical estimation problem known as atomic deconvolution. Introduced in reliability, this model has a direct application when considering biological data produced by flow cytometers. From a statistical point of view, we aim at inferring the percentage of cells expressing the selected molecule and the probability distribution function associated with its fluorescence emission. We propose here an adaptive estimation procedure based on a previous deconvolution procedure introduced by Es, Gugushvili, and Spreij [(2008), ‘Deconvolution for an atomic distribution’, Electronic Journal of Statistics, 2, 265–297] and Gugushvili, Es, and Spreij [(2011), ‘Deconvolution for an atomic distribution: rates of convergence’, Journal of Nonparametric Statistics, 23, 1003–1029]. For both estimating the mixing parameter and the mixing density automatically, we use the Lepskii method based on the optimal choice of a bandwidth using a bias-variance decomposition. We then derive some convergence rates that are shown to be minimax optimal (up to some log terms) in Sobolev classes. Finally, we apply our algorithm on the simulated and real biological data. 相似文献
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Laurent Somme Laura Moquet Muriel Quinet Maryse Vanderplanck Denis Michez Georges Lognay Anne-Laure Jacquemart 《Urban Ecosystems》2016,19(3):1149-1161
Urbanization affects the availability and diversity of floral resources (pollen and/or nectar) for wild pollinating insects. For example, urban green areas are characterized by an abundance of ornamental plant species. Increasingly, trees are planted to improve the aesthetics of urban streets and parks. These urban trees might offer important floral resources to pollinating insects. To examine the suitability of urban trees as resources for pollinating insects, we investigated the chemical composition of pollen and nectar as well as the amount of nectar produced by the nine major insect-pollinated tree species planted in cities of Western Europe, namely Acer pseudoplatanus, Aesculus carnea, A. hippocastanum, Robinia pseudoacacia, Tilia cordata, T. x euchlora, T. x europaea, T. platyphyllos and T. tomentosa. The analyses revealed that globally the Tilia trees provide pollen with lower contents of polypeptides, amino acids and phytosterols compared with the other species. Urban tree flowers offer abundant nectar with relatively high sugar contents (0.16–1.28 mg/flower); sucrose was the predominant sugar in all nectars. The investigated tree species could therefore be considered in future city plantings. 相似文献
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Laurent Adrien Garaudel Pierre Schmidt Géraldine Eynaud Philippe 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2020,31(1):19-38
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - To cope with the new challenges inherent to their political role, civil society organizations must convince their... 相似文献
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Laurent Gourvès Jérôme Monnot Lydia Tlilane 《Journal of Combinatorial Optimization》2018,36(3):937-964
We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees. 相似文献
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“They Make Me Not Wanna Have a Child”: Effects of Companion Animals on Fertility Intentions of the Childfree 下载免费PDF全文
Andrea Laurent‐Simpson 《Sociological inquiry》2017,87(4):586-607
This article argues that for some who are childfree, the increasing perception of the companion animal as a sentient being with agency provides a deep, meaningful relationship with the power to inform fertility intentions. Qualitative, in‐depth interviews with childfree companion animal owners reveal that this relationship serves to reinforce previous fertility choices such as delaying or completely opting out of childbirth, thus affecting present household structure. This is reflected in the active choice by some participants to have companion animals instead of human children, the presence of a cost‐benefit analysis concerning animal companions and human children, and narratives that express a desire to mother or nurture as fulfilled in the relationship with the companion animal. Implications of these findings for both demography and marriage and family research in the United States are discussed. 相似文献
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This paper is the first attempt to assess, in a unified econometric framework, the existence and the magnitude of both the sexual orientation participation gap and the sexual orientation unemployment gap. Having identified male same-sex couples using the Employment Survey, we use a bivariate probit selection model where the labor supply and the employment equation are jointly estimated for the French labor market. The results show that both participation and employment probabilities are significantly lower for gay employees compared to their heterosexual counterparts. Further investigations indicate that young gay workers, particularly, are more exposed to the unemployment risk than older ones. The beginning of a professional career and the subsequent entry to the labor market appear to be difficult steps to overcome for gay workers who spend more time than their heterosexual counterparts to find the good job. 相似文献
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Kaatje Els Bollaerts Winy Messens Laurent Delhalle Marc Aerts Yves Van der Stede Jeroen Dewulf Sophie Quoilin Dominiek Maes Koen Mintiens Koen Grijspeerdt 《Risk analysis》2009,29(6):820-840
A quantitative microbial risk assessment (QMRA) according to the Codex Alimentarius Principles is conducted to evaluate the risk of human salmonellosis through household consumption of fresh minced pork meat in Belgium. The quantitative exposure assessment is carried out by building a modular risk model, called the METZOON-model, which covers the pork production from farm to fork. In the METZOON-model, the food production pathway is split up in six consecutive modules: (1) primary production, (2) transport and lairage, (3) slaughterhouse, (4) postprocessing, (5) distribution and storage, and (6) preparation and consumption. All the modules are developed to resemble as closely as possible the Belgian situation, making use of the available national data. Several statistical refinements and improved modeling techniques are proposed. The model produces highly realistic results. The baseline predicted number of annual salmonellosis cases is 20,513 ( SD 9061.45). The risk is estimated higher for the susceptible population (estimate 4.713 × 10−5 ; SD 1.466 × 10−5 ) compared to the normal population (estimate 7.704 × 10−6 ; SD 5.414 × 10−6 ) and is mainly due to undercooking and to a smaller extent to cross-contamination in the kitchen via cook's hands. 相似文献