Size-assortative mating in simultaneous hermaphrodites: an experimental test and a meta-analysis

Assortative mating by size has been argued to be widespread in the animal kingdom. However, the strength of size-assortative mating is known to vary considerably between species and the underlying mechanisms promoting this inter-specific variation remain largely unexplored. Size-assortative mating has been proposed to be particularly strong in simultaneous hermaphrodites, i.e. organisms that produce male and female gametes at the same time. Here, we build on this hypothesis by arguing that size-assortative mating mediated by sexual selection is generally stronger in reciprocally mating hermaphrodites compared with unilaterally mating species and separate-sexed organisms. We report a series of empirical tests suggesting that size-assortative mating in the unilaterally copulating freshwater snail Physa acuta is caused by spatial clustering of similar-sized individuals and not by mate choice. In addition, we present a meta-analysis testing, for the first time, the hypothesis that sexual selection-mediated size-assortative mating is stronger in reciprocally copulating simultaneous hermaphrodites. Overall, we found significant size-assortative mating across 18 tested species and substantial inter-specific variation. Importantly, part of this variation can be explained by mating type, providing support for the hypothesis that size-assortative mating is stronger in reciprocally mating hermaphrodites compared with unilaterally mating species. We highlight potential pitfalls when testing for sexual selection-mediated size-assortative mating and discuss the need for more experimental and comparative approaches in order to resolve the observed variation in the strength of size-assortative mating among species.Fil: Graham, Stuart. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Université Paul-Valéry Montpellier; Francia. Centre National de la Recherche Scientifique; FranciaFil: Chapuis, Elodie. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Institut de Recherche pour le Développement,. Intéractions Plantes-Microrganismes-Environement; Francia. Université Paul-Valéry Montpellier; FranciaFil: Meconcelli, Stefania. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Università di Torino; ItaliaFil: Bonel, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados I; Argentina. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Université Paul-Valéry Montpellier; FranciaFil: Sartori, Kevin. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Université Paul-Valéry Montpellier; FranciaFil: Christophe, Ananda. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Université Paul-Valéry Montpellier; FranciaFil: Alda, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Patrice David. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Université Paul-Valéry Montpellier; FranciaFil: Janicke, Tim. Université de Montpellier. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Centre National de la Recherche Scientifique; Francia. Université Paul-Valéry Montpellier; Franci

Dynamic Lambda-Field: A Counterpart of the Bayesian Occupancy Grid for Risk Assessment in Dynamic Environments

In the context of autonomous vehicles, one of the most crucial tasks is to estimate the risk of the undertaken action. While navigating in complex urban environments, the Bayesian occupancy grid is one of the most popular types of maps, where the information of occupancy is stored as the probability of collision. Although widely used, this kind of representation is not well suited for risk assessment: because of its discrete nature, the probability of collision becomes dependent on the tessellation size. Therefore, risk assessments on Bayesian occupancy grids cannot yield risks with meaningful physical units. In this article, we propose an alternative framework called Dynamic Lambda-Field that is able to assess generic physical risks in dynamic environments without being dependent on the tessellation size. Using our framework, we are able to plan safe trajectories where the risk function can be adjusted depending on the scenario. We validate our approach with quantitative experiments, showing the convergence speed of the grid and that the framework is suitable for real-world scenarios.Comment: 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other work

Indium antimonide photovoltaic cells for near-field thermophotovoltaics

International audienceIndium antimonide photovoltaic cells are specifically designed and fabricated for use in a near-field thermophotovoltaic device demonstrator. The optimum conditions for growing the p-n junction stack of the cell by means of solid-source molecular beam epitaxy are investigated. Then processing of circular micron-sized mesa structures, including passivation of the side walls, is described. The resulting photovoltaic cells, cooled down to around 77 K in order to operate optimally, exhibit excellent performances in the dark and under far-field illumination by thermal sources in the [600-1000] °C temperature range. A short-circuit current beyond 10 µA, open-circuit voltage reaching almost 85 mV, fill factor of 0.64 and electrical power at the maximum power point larger than 0.5 W are measured for the cell with the largest mesa diameter under the highest illumination. These results demonstrate that these photovoltaic cells will be suitable for measuring a near-field enhancement of the generated electrical power

Annotation de partitions musicales dynamiques

Cet article traite de l'annotation visuelle à main levée de partitions musicales dynamiques : par dynamique, nous entendons la possibilité de recomposer, à la volée, les différents objets graphiques à l'intérieur de la page, ce qui nécessite de représenter les différentes annotations en conséquence. Nous décrivons ici les difficultés rencontrées et les solutions apportées au fil du développement de cet outil

Size-assortative mating in simultaneous hermaphrodites: an experimental test and a meta-analysis

Assortative mating by size has been argued to be widespread in the animal kingdom. However, the strength of size-assortative mating is known to vary considerably between species and the underlying mechanisms promoting this inter-specific variation remain largely unexplored. Size-assortative mating has been proposed to be particularly strong in simultaneous hermaphrodites, i.e. organisms that produce male and female gametes at the same time. Here, we build on this hypothesis by arguing that size-assortative mating mediated by sexual selection is generally stronger in reciprocally mating hermaphrodites compared with unilaterally mating species and separate-sexed organisms. We report a series of empirical tests suggesting that size-assortative mating in the unilaterally copulating freshwater snail Physa acuta is caused by spatial clustering of similar-sized individuals and not by mate choice. In addition, we present a meta-analysis testing, for the first time, the hypothesis that sexual selection-mediated size-assortative mating is stronger in reciprocally copulating simultaneous hermaphrodites. Overall, we found significant size-assortative mating across 18 tested species and substantial inter-specific variation. Importantly, part of this variation can be explained by mating type, providing support for the hypothesis that size-assortative mating is stronger in reciprocally mating hermaphrodites compared with unilaterally mating species. We highlight potential pitfalls when testing for sexual selection-mediated size-assortative mating and discuss the need for more experimental and comparative approaches in order to resolve the observed variation in the strength of size-assortative mating among species.Centro de Estudios Parasitológicos y de Vectore

Reference gene selection for head and neck squamous cell carcinoma gene expression studies

<p>Abstract</p> <p>Background</p> <p>It is no longer adequate to choose reference genes blindly. We present the first study that defines the suitability of 12 reference genes commonly used in cancer studies (<it>ACT, ALAS, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPL27, RPS29, SHAD </it>and <it>TBP</it>) for the normalization of quantitative expression data in the field of head and neck squamous cell carcinoma (HNSCC).</p> <p>Results</p> <p>Raw expression levels were measured by RT-qPCR in HNSCC and normal matched mucosa of 46 patients. We analyzed the expression stability using geNorm and NormFinder and compared the expression levels between subgroups. In HNSCC and/or normal mucosa, the four best normalization genes were <it>ALAS, GAPDH, RPS18 </it>and <it>SHAD </it>and the most stable combination of two genes was <it>GAPDH-SHAD</it>. We recommend using <it>KALPHA-TBP </it>for the study of T1-T2 tumors, <it>RPL27-SHAD </it>for T3-T4 tumors, <it>KALPHA-SHAD </it>for N0 tumors, and <it>ALAS-TBP </it>for N+ tumors. <it>ACT, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPS29, SHAD </it>and <it>TBP </it>were slightly misregulated (<1.7-fold) between tumor and normal mucosa but can be used for normalization, depending on the resolution required for the assay.</p> <p>Conclusion</p> <p>In the field of HNSCC, this study will guide researchers in selecting the most appropriate reference genes from among 12 potentially suitable reference genes, depending on the specific setting of their experiments.</p