Search results for " Variation"

A simulation function approach for best proximity point and variational inequality problems

2017

We study sufficient conditions for existence of solutions to the global optimization problem min(x is an element of A) d(x, fx), where A, B are nonempty subsets of a metric space (X, d) and f : A -> B belongs to the class of proximal simulative contraction mappings. Our results unify, improve and generalize various comparable results in the existing literature on this topic. As an application of the obtained theorems, we give some solvability theorems of a variational inequality problem.

Cryptic microgeographic variation in responses of larval Atlantic cod to warmer temperatures

2021

AbstractAlthough temperature is known to drive species dynamics and distributions, our understanding of the extent to which thermal plasticity varies within species is poor. Differences in plasticity can arise through local adaptation to heterogeneous environments, hybridization, and the release of cryptic genetic variation in novel environments. Here, wild Atlantic cod (Gadus morhua) from contrasting environments inside and outside of a fjord system in southern Norway spawned freely in a semi-natural laboratory environment, generating pure crosses and reciprocal hybrids. A common-garden rearing experiment of the larvae at 6°C, 9.5°C, and 13°C revealed cryptic genetic variation in thermal r…

The effect of periodic bottlenecks on the competitive ability of Drosophila pseudoobscura lines.

1993

Competition experiments between several Drosophila pseudoobscura strains that were previously subjected to periodic bottlenecks of different sizes and D. willistoni have been carried out. Contrary to previous results with these two species, where stable coexistence was detected, populations of D. pseudoobscura displaced D. willistoni in a few generations. By using a relative fitness measure, the control lines (that had not gone through bottlenecks) outcompeted D. willistoni faster than bottlenecked lines. One of these, corresponding to the minimum possible bottleneck size of one pair, also shows significantly lower relative fitness than the other strains. These results are discussed in rela…

ArchiRac : Caractérisation de la diversité génétique de l’architecture racinaire chez le blé tendre et le blé dur

2019

National audience; Le système racinaire constitue la partie invisible des plantes mais il joue néanmoins un rôleprimordial dans leur développement. C’est par le système racinaire que la plante va prélever deséléments qui sont indispensables à sa survie, et c’est donc, au moins en partie, les caractéristiques dece système racinaire qui vont lui permettre de résister à des stress abiotiques. Il a été notammentmontré que des caractères liés à l’architecture racinaire pouvaient être responsables d’une meilleuretolérance à des stress hydriques. Le projet FSOV ArchiRac vise à caractériser un grand nombre devariétés élites et de diversité de blé tendre et de blé dur pour leur architecture racinair…

Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

2006

Introduction and objectives. The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. Methods. Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. Results. Linear regression analysis showed that there was a good correlation between …

Anatomic variation of the vertebral artery

2016

Is work engagement related to healthy cardiac autonomic activity? Evidence from a field study among Finnish women workers

2012

The present study investigated whether work engagement is related to and can explain healthy cardiac autonomic activity as indicated by decreased heart rate (HR; i.e., sympathetic and parasympathetic activity) and increased high-frequency power (HFP) of heart rate variability (i.e., parasympathetic activity). A total of 30 healthy Finnish female cleaning workers underwent an ambulatory monitoring period of two nights and two regular workdays, and mean values of work period HR and HFP were utilized as dependent variables. Correlations revealed that work engagement was, as hypothesized, negatively related to HR and positively to HFP. Furthermore, in hierarchical linear regression analysis, wo…

Genetic and Molecular Characterization of The Human Osteosarcoma 3AB-OS Cancer Stem Cell Line: A Possible Model For Studying Osteosarcoma Origin and …

2013

Finding new treatments targeting cancer stem cells (CSCs) within a tumor seems to be critical to halt cancer and improve patient survival. Osteosarcoma is an aggressive tumor affecting adolescents, for which there is no second-line chemotherapy. Uncovering new molecular mechanisms underlying the development of osteosarcoma and origin of CSCs is crucial to identify new possible therapeutic strategies. Here, we aimed to characterize genetically and molecularly the human osteosarcoma 3AB-OS CSC line, previously selected from MG63 cells and which proved to have both in vitro and in vivo features of CSCs. Classic cytogenetic studies demonstrated that 3AB-OS cells have hypertriploid karyotype wit…

Statistical Picking of Multivariate Waveforms

2022

In this paper, we propose a new approach based on the fitting of a generalized linear regression model in order to detect points of change in the variance of a multivariate-covariance Gaussian variable, where the variance function is piecewise constant. By applying this new approach to multivariate waveforms, our method provides simultaneous detection of change points in functional time series. The proposed approach can be used as a new picking algorithm in order to automatically identify the arrival times of P- and S-waves in different seismograms that are recording the same seismic event. A seismogram is a record of ground motion at a measuring station as a function of time, and it typica…

ESR of Nd3+ in BaTiO3

1990

Afin d'identifier les defauts responsables de l'effet photo-refractif dans BaTiO 3 , on etudie ces cristaux. Les echantillons contiennent generalement divers etats de charge et des associations de Fe, Cr, ainsi que des trous de O − induits par le rayonnement. On trouve un nouveau centre qui doit etre attribue a Nd 3+ . Dans la presente etude, l'echantillon utilise n'est pas dope, et on l'etudie dans la phase rhomboedrique a T∼77 K. Il apparait que Na est une impurete courante dans BaTiO 3 probablement incorporee avec le materiau de depart, BaCO 3