L'influence de la sélection fréquence-dépendante sur le choix de partenaire chez le diamant mandarin (Taeniopygia guttata)

La sélection fréquence-dépendante est un mécanisme d’évolution selon lequel l’aptitude d'un type varie en fonction de sa fréquence dans la population. Ce mécanisme joue un rôle important dans de nombreuses interactions autant interspécifiques (parasitisme, prédation, compétition), qu'intra-spécifiques entre les différents phénotypes d'une même espèce. La sélection fréquence-dépendante peut être positive ou négative et favoriser alors les phénotypes communs ou rares, respectivement. Elle a été mise en évidence dans le contexte du choix de partenaire chez plusieurs espèces, notamment chez certaines espèces d'insectes (ex.: demoiselles, drosophiles, cantharide de Pennsylvanie) et de poissons (ex.: guppys, xiphos), mais elle a été aussi récemment découverte chez l’humain. L'importance de la sélection fréquence-dépendante dans le choix de partenaire chez les espèces monogames reste tout de même peu explorée et cette étude vise à combler cette lacune en utilisant le diamant mandarin, un passereau monogame, comme modèle biologique. Nous avons étudié l'importance de ce mécanisme lorsqu'un trait est neutre et lorsque celui-ci constitue un indicateur de qualité. De plus, nous avons tenté de déterminer si la présence de rivales peut modifier la préférence initiale des femelles pour les phénotypes rares ou communs.

A voyage to Cochinchina, in the years 1792 and 1793 : containing a general view of the valuable productions and the political importance of this flourishing kingdom, and also of such European settlements as were visited on the voyage: with sketches of the manners, character, and condition of their several inhabitants : To which is annexed an account of a journey, made in the years 1801 and 1802, to the residence of the chief of the Booshuana nationa, being the remotest point in the interior of southern Africa to which Europeans have hitherto penetrated ... /

An account of a journey to Leetakoo, the residence of the chief of the booshuana nation ... : the facts and descriptions taken from a manuscript journal : p. 361-437.

A sketch of the life and character of the Rev. David Caldwell, D. D. near sixty years pastor of the churches of Buffalo and Alamance. Including two of his sermons; some account of the Regulation, together with the revolutionary ... incidents in which he was concerned; and a very brief notice of the ecclesiastical and moral condition of North-Carolina while in its colonial state,

Mode of access: Internet.

The catechism of the church; with a larger catechism on the character of God, condition of man, etc. To which are added, offices of devotion for Sunday schools.

Mode of access: Internet.

The works of Robert Burns : with an account of his life, and criticism on his writing ; to which are prefixed some observations on the character and condition of the Scottish peasantry by James Currie, M. D. ; with many additional poems and songs and an enlarged and corrected glossary.

Includes index.

Seventy-five years in old Virginia; with some account of the life of the author and some history of the people amongst whom his lot was cast,--their character, their condition, and their conduct before the war, during the war and after the war,

Mode of access: Internet.

Ireland, as I saw it: the character, condition, and prospects of the people.

Mode of access: Internet.

The history of Arabia, ancient and modern : containing a description of the country--an account of its inhabitants, antiquities, political condition, and early commerce--the life and religion of Mohammed--the conquests, arts, and literature of the Saracens--the caliphs of Damascus, Bagdad, Africa, and Spain--the civil government and religious ceremonies of the modern Arabs--origin and suppression of the Wahabes--the institutions, character, manners, and customs of the bedouins; and a comprehensive view of its natural history /

Mode of access: Internet.

The works of Robert Burns; with an account of his life, and a criticism on his writings. To which are prefixed, some observations on the character and condition of the Scottish peasantry ...

"A reprint of Dr. Currie's second edition." cf. J. Gibson. The bibliography of Robert Burns.

A treatise on the intellectual character and civil and political condition of the Colored people of the U. States and the prejudice exercised towards them /

"The sermon as proposed in our title page, is omitted."

A description of active and extinct volcanos; with remarks on their origin, their chemical phaenomena, and the character of their products, as determined by the condition of the earth during the period of their formation. Being the substance of some lectures delivered before the University of Oxford, with much additional matter.

Bibliography: p. [453]-466.

Works of Robert Burns: with an account of his life, and criticism on his writings. to which are prefixed, some observtions on the character and condition of the Scottish peasantry.

Mode of access: Internet.

Accelerated multistress aging of polymer nanocomposites and its condition monitoring

In recent years, the time dependant maintenance of expensive high voltage power equipments is getting replaced by condition based maintenance so as to detect apriori an impending failure of the equipment. For condition based maintenance, most monitoring systems concentrate on the electrical quantities such as measurement and evaluation of partial discharges, tan delta, tip-up test, dielectric strength, insulation resistance, polarization and depolarization current. However, in the case of equipments being developed with novel nanodielectric insulating materials, the variation in these parameters before an impending failure is not available. Hence in this work, accelerated electrothermal aging studies have been conducted on unfilled epoxy as well as epoxy nanocomposite samples of 5 wt% filler loading, and the tan d values were continuously monitored to obtain the condition of the samples under study. It was observed that those samples whose tan d increased at a rapid rate failed first.

Using epilithic diatom communities to assess ecological condition of Xiangxi River system

Assessment method for ecological condition of Xiangxi River system was studied by using 13 candidate metrics of epilithic diatom which can reflect conditions in pH, salinity, nitrogen uptake metabolism, oxygen requirements, saprobity, trophic state, morphological character and pollution tolerant capability etc. By one-way ANOVA, the metrics of relative abundance of acidobiontic algae (ACID), freshwater algae (FRESH), high oxygen requirement (HIGH-O), eutraphentic state (EUTRA) and mobile taxa ( MOBILE) were suitable for distinguishing sites in different conditions. Then, the river diatom index (RDI) composed of these five metrics was used to evaluate ecological condition of the river. The results showed that the healthiest sites were in the Guanmenshan Natural Reserve ( with the mean RDI of 79.73). The sites located in tributary of Jiuchong River also owned excellent state (mean RDI of 78.25). Mean RDI of another tributary - Gufu River and the main river were 70.85 and 68.45 respectively, and the unhealthiest tributary was Gaolan River (with mean RDI of 65.64). The mean RDI for all the 51 sites was 71.40. The competence of RDI was discussed with comparison of evaluation results of DAIpo and TDI, it can be concluded that multimetrics is more competent in assessment task.

The developmental character of cardiac autonomic responses to an acute noxious event in 4- and 8-month-old healthy infants

Heart rate (HR) has been widely studied as a measure of an individual's response to painful stimuli. It remains unclear whether changes in mean HR or the variability of HR are specifically related to the noxious stimulus (i.e. pain). Neither is it well understood how such changes reflect underlying neurologic control mechanisms that produce these responses, or how these mechanisms change during the first year of life. To study the changes in cardiac autonomic modulation that occur with acute pain and with age during early infancy, the relationship between respiratory activity and short-term variations of HR (i.e. respiratory sinus arrhythmia) was quantified in a longitudinal study of term born healthy infants who underwent a finger lance blood collection at 4 months of age (n = 24) and again at 8 months of age (n = 20). Quantitative respiratory activity and HR were obtained during baseline, lance, and recovery periods. Time and frequency domain analyses from 2.2-min epochs of data yielded mean values, spectral measures of low (0.04-0.15 Hz) and high (0.15-0.80 Hz) frequency power (LF and HF), and the LF/HF ratio. To determine sympathetic and parasympathetic cardiac activity, the transfer relation between respiration and HR was used. At both 4 and 8 months, mean HR increased significantly with the noxious event (p > 0.01). There were age-related differences in the pattern of LF, HF, and LF/HF ratio changes. Although these parameters all decreased (p > 0.01) at 4 months, LF and LF/HF increased at 8 months and at 8 months HF remained stable in response to the noxious stimulus. Transfer gain changes with the lance demonstrated a change from predominant vagal baseline to a sympathetic condition at both ages. The primary finding of this study is that a response to an acute noxious stimulus appears to produce an increase in respiratory-related sympathetic HR control and a significant decrease in respiratory-related parasympathetic control at both 4 and 8 months. Furthermore, with increasing age, the sympathetic and parasympathetic changes appear to be less intense, but more sustained.