Inferring Deleterious-Mutation Parameters in Natural Daphnia Populations

Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch's (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient ( [Image: see text] ), mean selection coefficient ( [Image: see text] ), and scaled genomic mutational variance ( [Image: see text] ). On average, [Image: see text] , [Image: see text] , [Image: see text] and [Image: see text] (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the [Image: see text] and [Image: see text] are lower bounds, and [Image: see text] and [Image: see text] upper bounds

Loss of Coolant Accident Testing Round Robin

International audienc

Synthesis, structure, and electrical behavior of Sr4Bi4Ti7O24

An n=7 Aurivillius phase, Sr4Bi4Ti7O24, with c=6.44 nm, was synthesized as an epitaxial (001)-oriented film. This phase and its purity were confirmed by x-ray diffraction and transmission electron microscopy. The material is ferroelectric, with a P-r=5.3 mu C/cm(2) oriented in the (001) plane and a paraelectric-to-ferroelectric transition temperature of T-C=324 K. Some indications of relaxorlike behavior are observed. Such behavior is out of character for Srn-1Bi2TinO3n+3 Aurivillius phases and is closer to the bulk behavior of doped SrTiO3, implying a spatial limit to the elastic interlayer interactions in these layered oxides. A finite-element solution to the interpretation of data from interdigitated capacitors on thin films is also described

Synthesis and characterization of an n=6 Aurivillius phase incorporating magnetically active manganese

Epitaxial films of Bi7Mn3.75Ti2.25O21 were prepared to yield a previously unsynthesized material. The superlattice phase is produced by incorporating the magnetoelectric BiMnO3 into the perovskite substructure of the ferroelectric Bi4Ti3O12, a strategy which is hoped to yield previously undiscovered multiferroic materials. X-ray diffraction and transmission electron microscopy (TEM) confirm synthesis of an epitaxial n=6 Aurivillius phase. Magnetization measurements show ferromagnetic behavior with a Curie point of 55 K, but electronic polarization measurements show no remanent polarization. Rutherford backscattering spectrometry indicates a channeling minimum chi(min) of 22%, consistent with the high density of out-of-phase domain boundaries observed by TEM. (C) 2007 American Institute of Physics

Estudo comparado da morfologia externa de Zaretis itys itylus (Westwood) e Agrias claudina annetta (Gray) (Lepidoptera, Nymphalidae, Charaxinae) I. Cabeça, apêndices e região cervical Comparative study of the external morphology of Zaretis itys itylus (Westwood) and Agrias claudina annetta (Gray) (Lepidoptera, Nymphalidae, Charaxinae). I. Head, appendages and cervical region

Realizou-se um estudo detalhado e comparado da morfologia externa da cabeça, apêndices e região cervical, de duas espécies de Charaxinae, Zaretis itys itylus (Westwood, 1850) e Agrias claudina annetta (Gray, 1832). Os resultados obtidos foram comparados com outros já publicados e relacionados com morfologia externa de outras subfamílias de Nymphalidae (Brassolinae, Morphinae, Danainae e Ithomiinae).<br>Two species of Charaxinae, Zaretis itys itylus (Westwood, 1850) and Agrias claudina annetta (Gray, 1832) were subject of a detailed and comparative study of external morphology of the head, appendages and cervical region. The results obtained were compared with other studies published and related to the external morphology of other Nymphalidae subfamilies (Brassolinae, Morphinae, Danainae and Ithomiinae)