Search results for "SELE"
showing 10 items of 4721 documents
Diastereomeric control of enantioselectivity: evidence for metal cluster catalysis
2014
Enantioselective hydrogenation of tiglic acid effected by diastereomers of the general formula [(μ-H)2Ru3(μ3-S)(CO)7(μ-P–P*)] (P–P* = chiral Walphos diphosphine ligand) strongly supports catalysis by intact Ru3 clusters. A catalytic mechanism involving Ru3 clusters has been established by DFT calculations. peerReviewed
Nuevas estrategias para estimar la calidad embrionaria y el éxito de las embrio-transferencias mediante la evaluación no invasiva y selección automát…
2022
La introducción de la tecnología de lapso de tiempo en la práctica clínica de fecundación in vitro permitió la supervisión ininterrumpida de los embriones durante todo el período de cultivo. Inicialmente, el objetivo principal era lograr un mejor desarrollo embrionario. Sin embargo, esta tecnología también introdujo el novedoso concepto de la morfocinética, parámetros relacionados con la dinámica de las células embrionarias. La gran cantidad de datos obtenidos permitió definir los rangos óptimos de la duración del ciclo celular en diferentes etapas del desarrollo del embrión, lo cual añadió información complementaria para asistir en la evaluación del embrión antes de la transferencia. Los m…
Nuevas metodologías para la selección no invasiva de embriones humanos en tratamientos de reproducción asistida: introducción de la inteligencia arti…
2023
La evaluación y selección de embriones en los tratamientos de fecundación in vitro (FIV) se realiza manualmente de forma convencional, mediante observaciones puntuales bajo el microscopio durante el desarrollo embrionario. Dicho análisis altera las condiciones de cultivo, pudiendo afectar a las tasas de éxito del tratamiento de reproducción asistida. La introducción de la microscopía de lapso de tiempo o time-lapse, ha hecho posible un seguimiento continuo de los embriones in vitro. De esta forma, se obtiene rutinariamente gran cantidad de información en formato de imágenes grabadas. Hoy en día, el análisis de este material todavía se realiza manualmente y las imágenes se utilizan sobre tod…
Dendrochronologie : potentialités et nouveaux enjeux pour l’archéologie préventive
2019
International audience; La dendrochronologie, méthode de datation qui étudie la variation des largeurs des cernes de croissance des arbres, est sollicitée, en archéologie, pour l’obtention d’une date absolue. Elle nécessite un dialogue incontournable entre les différents acteurs de la discipline pour fiabiliser les acquisitions, voire tout simplement obtenir une date. L’analyse des bois archéologiques ne se limite toutefois pas à la seule datation et constitue le point de départ de nouvelles approches qui permettent de combler des espaces et des champs de recherche encore lacunaire, pour le sud de la France notamment. Dans le contexte des changements climatiques actuels, la dendrochronologi…
Artificial selection of microbial communities: the effect of diversity and the role of interspecific interactions
2021
In agriculture, the plants and animals that are bred come from long-term artificial selection procedures that aim at producing individuals with desirable traits. Such procedures can be applied at levels of biological organization higher than the individual such as the community level, which is of particular interest in the field of microbial community engineering. Indeed, microbial communities play key roles in agriculture but also in the environment, health and industry, and a growing body of literature shows promising results regarding the artificial selection of microbial communities for desirable functions. However, for artificial selection procedures at the community level to be effici…
Progress in Understanding of the Interactions between Functionalized Polyolefins and Organo-Layered Double Hydroxides
2014
The dispersion of organo-layered double hydroxides (O-LDH) in functionalized polyolefins (POs) is investigated. Two different polyethylene matrices (maleic anhydride (MAH) and diethyl maleate functionalized) are tested and a hydrogenated fatty acid modified LDH is used. The attention is focused on evidencing the interaction between the functional groups of the polymer and the O-LDH through FT-IR. Moreover, a combination of solvent fractionation, morphological, and rheological characterizations enables to gain a deeper insight into the structure of these composites. In particular, the formation of bridging bonds between the particles and MAH functionalized macromolecules is assumed, possibly…
Genomic divergence landscape in recurrently hybridizing Chironomus sister taxa suggests stable steady state between mutual gene flow and isolation
2021
Abstract Divergence is mostly viewed as a progressive process often initiated by selection targeting individual loci, ultimately resulting in ever increasing genomic isolation due to linkage. However, recent studies show that this process may stall at intermediate stable equilibrium states without achieving complete genomic isolation. We tested the extent of genomic isolation between two recurrently hybridizing nonbiting midge sister taxa, Chironomus riparius and Chironomus piger, by analyzing the divergence landscape. Using a principal component‐based method, we estimated that only about 28.44% of the genomes were mutually isolated, whereas the rest was still exchanged. The divergence land…
Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence.
2017
A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy–fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group assistance and chemodifferentiation.
Improved measurement of the 02+→01+ E0 transition strength for 72Se using the SPICE spectrometer
2022
The selenium isotopes lie at the heart of a tumultuous region of the nuclear chart where shape coexistence effects grapple with neutron-proton pairing correlations, triaxiality, and the impending proton drip line. In this work, a study of 72Se by internal conversion electron and γ-ray spectroscopy was undertaken with the SPICE and TIGRESS arrays. New measurements of the branching ratio and lifetime of the 02+ state were performed, yielding a determination of ρ2(E0;02+→01+)=29(3) milliunits. Two-state mixing calculations were performed that highlighted the importance of interpretation of such E0 strength values in the context of shape coexistence. peerReviewed
BETWEEN SUBJECTIVE AND OBJECTIVE IN MAKING DECISIONS ON THE ROMANIAN HIGHER EDUCATION MARKET
2012
Having roots in intentional behaviours, adverse selection as part of information asymmetry is a widely - discussed concept, closely related to many sides of economics and generating the most various problems in practice. As the specific literature says, the adverse selection leads, or at least in theory should lead to market failure when no external force comes to balance its effects. Since this failure never occurs in fact, it is questionable whether the adverse selection is the only factor that influences an uniformed consumer decision, or other factors come to counterbalance the factors described by Akerloff. This paper intends to advocate the idea that as much as adverse selection, ther…