90 research outputs found
Clusters of galaxies : observational properties of the diffuse radio emission
Clusters of galaxies, as the largest virialized systems in the Universe, are
ideal laboratories to study the formation and evolution of cosmic
structures...(abridged)... Most of the detailed knowledge of galaxy clusters
has been obtained in recent years from the study of ICM through X-ray
Astronomy. At the same time, radio observations have proved that the ICM is
mixed with non-thermal components, i.e. highly relativistic particles and
large-scale magnetic fields, detected through their synchrotron emission. The
knowledge of the properties of these non-thermal ICM components has increased
significantly, owing to sensitive radio images and to the development of
theoretical models. Diffuse synchrotron radio emission in the central and
peripheral cluster regions has been found in many clusters. Moreover
large-scale magnetic fields appear to be present in all galaxy clusters, as
derived from Rotation Measure (RM) studies. Non-thermal components are linked
to the cluster X-ray properties, and to the cluster evolutionary stage, and are
crucial for a comprehensive physical description of the intracluster medium.
They play an important role in the cluster formation and evolution. We review
here the observational properties of diffuse non-thermal sources detected in
galaxy clusters: halos, relics and mini-halos. We discuss their classification
and properties. We report published results up to date and obtain and discuss
statistical properties. We present the properties of large-scale magnetic
fields in clusters and in even larger structures: filaments connecting galaxy
clusters. We summarize the current models of the origin of these cluster
components, and outline the improvements that are expected in this area from
future developments thanks to the new generation of radio telescopes.Comment: Accepted for the publication in The Astronomy and Astrophysics
Review. 58 pages, 26 figure
LEARN 2 MOVE 0-2 years:effects of a new intervention program in infants at very high risk for cerebral palsy; a randomized controlled trial
Background: It is widely accepted that infants at risk for cerebral palsy need paediatric physiotherapy. However, there is little evidence for the efficacy of physiotherapeutic intervention. Recently, a new intervention program, COPCA (Coping with and Caring for infants with special needs - a family centered program), was developed. COPCA has educational and motor goals. A previous study indicated that the COPCA-approach is associated with better developmental outcomes for infants at high risk for developmental disorders. LEARN 2 MOVE 0-2 years evaluates the efficacy and the working mechanisms of the COPCA program in infants at very high risk for cerebral palsy in comparison to the efficacy of traditional infant physiotherapy in a randomized controlled trial. The objective is to evaluate the effects of both intervention programs on motor, cognitive and daily functioning of the child and the family and to get insight in the working elements of early intervention methods.Methods/design: Infants are included at the corrected age of 1 to 9 months and randomized into a group receiving COPCA and a group receiving traditional infant physiotherapy. Both interventions are given once a week during one year. Measurements are performed at baseline, during and after the intervention period and at the corrected age of 21 months. Primary outcome of the study is the Infant Motor Profile, a qualitative evaluation instrument of motor behaviour in infancy. Secondary measurements focus on activities and participation, body functions and structures, family functioning, quality of life and working mechanisms. To cope with the heterogeneity in physiotherapy, physiotherapeutic sessions are video-recorded three times (baseline, after 6 months and at the end of the intervention period). Physiotherapeutic actions will be quantified and related to outcome.Discussion: LEARN 2 MOVE 0-2 years evaluates and explores the effects of COPCA and TIP. Whatever the outcome of the project, it will improve our understanding of early intervention in children with cerebral palsy. Such knowledge is a prerequisite for tailor-made guidance of children with CP and their families.Trial registration: The trial is registered under NTR1428.</p
Evaluation of the Chloride Requirement of the Broiler Breeder Hen Avaliação da ExigĂȘncia de Cloro para Matrizes Pesadas
Two experiments wore conducted to evaluate the chloride requirement of the broiler breeder hen. Experiments were conducted for a twelve-week period and seven experimental diets wore fed. The diets contained the following dietary chloride levels: 0. 040, 0. 047, 0. 054, 0.060, 0.073, 0.09g, and 0. 174%. Sodiam bicarbonate was used to maintain a constant level of sodium. Levels of dietary chloride below 0.054% reduced EF; EW, & EC (ED X (EW-shell wt). Also, the highest level of dietary chloride reduced all characteristics. Dietary chloride did not have a significant effect on body weight gain or fertility and hatchability of eggs. The Nationa/ Research Council (1994) suggests that the broller breeder hen have daily chloride intake of 185 milligrams per hen per day. In Experiments 1 and 2 the requirement was 96.1 mg/hen/day and 101. 1 mg/hen/day for EP, 116.1 mg/hen/day and 148.3 mg/hen/day for maximum EW, and 95.9 mg/hen/day and 109. 5 mg/hen/day for EC, respectively.<br>Foram conduzidos dois experimentos para avaliar o requerimento de cloro para matrizes pesadas. O perĂodo experimental foi de doze semanas e foram testadas sete raçÔes. As racĂ”es continham os seguintes nĂveis de cloro: 0,040, 0,047, 0,054, 0,060, 0,073, 0,099 e 1,74%. Foi utilizado o bicarbonato de sĂłdio para se manter um nĂvel constante de sĂłdio. Os nĂveis de cloro abaixo de 0,054% reduziram a produção, o peso e o conteĂșdo dos ovos, o mesmo ocorrendo com o nĂvel mais alto de cloro na ração. Os nĂveis de cloro nĂŁo exerceram um efeito significativo sobre o peso corporal, fertilidade e eclodibilidade dos ovos. ONRC (1994) sugere um nĂvel de 185mg de cloro por dia para matrizes pesadas. Nos experimentos 1 e 2, o requerimento encontrado foi de 96,1 mg/ave/dia e 101,1 mg/ave/dia para produção de ovos, 116,1 mg/ave/dia e 148,3 mg/ave/dia para peso mĂĄximo dos ovos e 95,9 mg/ave/dia e 109,5 mg/ave/dia para conteĂșdo do ovo, respectivamente
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