Search results for "Reproduction"

Chronic toxicity of methylparathion to Daphnia magna: Effects on survival, reproduction, and growth

1995

Comparative toxicant sensitivity of sexual and asexual reproduction in the rotiferBrachionus calyciflorus

1995

Cyclically parthenogenetic zooplankters like rotifers are important tools for assessing toxicity in aquatic environments. Sexual reproduction is an essential component of rotifer life cycles, but current toxicity tests utilize only asexual reproduction. The authors compared the effects of four toxicants on asexual and sexual reproduction of the rotifer Brachionus calyciflorus. Toxicants had a differential effect on sexual and asexual reproduction, with sexual reproduction consistently the most sensitive. Concentrations of 0.2 {mu}g/ml PCP (sodium pentachlorophenate) had no effect on the asexual reproductive rate, but significantly reduced sexual reproduction. Likewise, chlorpyrifos concentr…

De novo 13q deletions in two patients with mild anorectal malformations as part of VATER/VACTERL and VATER/VACTERL-like association and analysis of E…

2013

Item does not contain fulltext Anorectal malformations (ARMs) comprise a broad spectrum of conditions ranging from mild anal anomalies to complex cloacal malformations. In 40-50% of cases, ARM occurs within the context of defined genetic syndromes or complex multiple congenital anomalies, such as VATER/VACTERL (vertebral defects [V], ARMs [A], cardiac defects [C], tracheoesophageal fistula with or without esophageal atresia [TE], renal malformations [R], and limb defects [L]) association. Here, we report the identification of deletions at chromosome 13q using single nucleotide polymorphism-based array analysis in two patients with mild ARM as part of VATER/VACTERL and VATER/VACTERL-like ass…

Evaluation of in-farm versus weather station data for use as heat stress indicator in dairy sheep

2005

AbstractHeat stress is a limiting factor in dairy production in hot climates impairing growth, milk production and reproduction. The most widely investigated climatic factors related with heat stress are: air temperature and relative humidity. Previously dairy sheep studies of heat tolerance depended on measurements of physiological functions on individual animals such as rectal temperatures, respiration rates or volumes of air inhaled; unfortunately, such measurements are costly and not feasible on a large scale. This study aims to evaluate in-farm (IF) versus weather station (WS) data to be used as heat stress indicator in dairy sheep. Data were collected in three farms in November 2002 t…

LA DIVERSIDAD EN LAS IMÁGENES DE LOS MANUALES DEL PROFESOR DE EDUCACIÓN FÍSICA EN BRASIL

2021

RESUMO. A imagem é uma linguagem icônica com o poder de transmitir informações, reproduzir estereótipos e influenciar o professor. Este estudo trata dos manuais do professor de Educação Física elaborados no Brasil e aprovados no Programa Nacional do Livro e do Material Didático (BRASIL, 2017). Especificamente, analisa as imagens de pessoas neles existentes, com vistas a verificar se existem estereótipos relacionados às práticas corporais. Foi realizada a análise com 854 imagens por meio dos testes de Xis ao Quadrado de independência que revelaram estereótipos relacionados às práticas corporais. Os resultados mostram a predominância de grupos mistos de crianças, com corpos ectomorfos, de cor…

The comparative biology of the closely related Senecio nebrodensis and S. viscosus, a narrow endemic and a widespread ruderal

1993

The closely related Senecio nebrodensis, a perennial herb from four mountain ranges in Spain, and S. viscosus, an annual herb widespread in Europe, are being compared by the study of herbarium material and comparative cultivation. In cultivation, S. nebrodensis behaved as an annual, completing its life cycle within a shorter period of time than S. viscosus. The formation of basal leaf rosettes is much more pronounced in S. nebrodensis than in S.viscosus. The main difference between the two species, however, is their breeding system. While S. nebrodensis is self-incompatible, S. viscosus is self-compatible. Differences in reproductive morphology (mainly size and number of ray florets) are su…

Dynamics of the caring family

2003

When several individuals simultaneously provide for offspring, as in families, the effort of any one individual will depend on the efforts of the other family members. This conflict of interest among family members is made more complicated by their relatedness because relatives share genetic interest to some degree. The conflict resolution will also be influenced by the differences in reproductive value between breeders and helpers. Here, we calculate evolutionarily stable provisioning efforts in families with up to two helpers. We explicitly consider that the behavioral choices are made in a life-history context, and we also consider how group sizes change dynamically; this affects, for ex…

’-omics’ technology and human reproduction: reproductomics

2012

The success of assisted reproduction technology is highly dependent on a precise selection of gametes and embryos and determining the best endometrial window for embryo implantation. For many years, morphological criteria have constituted the only way to assess spermatozoon, oocytes, embryos and endometrial samples in order to improve outcomes. However, this approach has reached a ceiling of success and has been related to unacceptably high rates of multiple pregnancies. New technologies have been developed in order to improve the results and reduce risks via better selection of those gametes and embryos with the highest pregnancy potential, and of more favorable endometrial environments fo…

Despre fertilitatea erorilor. Imitație și inovație în învățământul superior, Robert D. Reisz, Editura Trei, București, 2018, 224 p.

2020

In his book, Robert Reisz approaches the challenging topic of the reproduction of the humboldtian and napoleonian models of higher education systems. It includes a thorough history of how these models appeared and a particularly interesting discussion about their diffusion across the world. Taking a neoinstitutional perspective, the author aims to describe the process of imitation (as a form of innovation) that is happening during the institutionalization of the models of universities in various historical, cultural and social settings. Apart from a specialists’ public – experts and academics – the book is addressing to a wide public, including any social actor involved or interested, eithe…

Innovationsschübe durch Außenseiter: Das Beispiel des Amateur-Astronomen William Herschel

1986

Innovatory advances by outsiders: The example of the amateur astronomer William Herschel. — Every scientific experience and perception has been gained from within a particular historical situation constituted by numerous components, both internal and external to a particular science, called praesentabilia (Prasentabilien). They enable and determine the scope and the experiental pale of any given science as well as its way and method of acquiring experience and knowledge. The interaction of such praesentabilia forms, what may be called the Historische Erfahrungsraum (‘historical field of experience’), which each individual and/or (greater/smaller) group shares in respectively. A scientific (…