O desafio de analisar solutos básicos por cromatografia líquida em modo reverso: algumas alternativas para melhorar as separações

This review considers some of the difficulties encountered with the analysis of basic solutes using reversed-phase chromatography, such as detrimental interaction with stationary phase silanol groups. Methods of overcoming these problems in reversed-phase separations, by judicious selection of the stationary phase and mobile phase conditions, are discussed. Developments to improve the chemical and thermal stability of stationary phases are also reviewed. It is shown that substantial progress has been made in the manufacturing of stationary phases, enabling their use over a wide variety of experimental conditions. In addition, general measures to significantly extend their lifespan are discussed.

Modelos estatísticos indicadores de comportamentos associados a bem-estar térmico para matrizes pesadas

The study of female broiler breeders is of great importance for the country as poultry production is one of the largest export items, and Brazil is the second largest broiler meat exporter. Animal behavior is known as a response to the effect of several interaction factors among them the environment. In this way the internal housing environment is an element that gives hints regarding to the bird s thermal comfort. Female broiler breeder behavior, expresses in form of specific pattern the bird s health and welfare. This research had the objective of applying predictive statistical models through the use of simulation, presenting animal comfort scenarios facing distinct environmental conditions. The research was developed with data collected in a controlled environment using Hybro - PG® breeding submitted to distinct levels of temperature, three distinct types of standard ration and age. Descriptive and exploratory analysis were proceeded, and afterwards the modeling process using the Generalized Estimation Equation (GEE). The research allowed the development of the thermal comfort indicators by statistical model equations of predicting female broiler breeder behavior under distinct studied scenarios.

O aluno portador de visão subnormal na escola regular: desafio para o professor?

Purpose:1) To check self-knowledge and needs for orientation among regular class teachers working with low vision students; 2) To gather information to assist the training on visual deficiency of regular class teachers. Methods: A survey was conducted for the academic year of 1999 among those teachers working in public schools, Campinas/SP/Brazil, of which 11 were municipal and 9 state schools, respectively 79.0% and 90.0% of these schools. A self-administered questionnaire was used as data collection instrument. Results: The sample was composed of 50 teachers with a regular class experience averaging 20 years. Most of them, 94.0%, said that they had no specific preparation in the area of low vision. Only 18 teachers declared to have received some kind of information/orientation in order to work with their low vision students and of those only 15 teachers mentioned the kind of orientation received. The whole group of 50 declared interest in receiving information. From the information/orientation requested 66.0% mentioned extended working class materials, 50.0% visual performance and eye disease of their students and 46.0% visual acuity/visual field. Conclusion: It was detected that teachers of regular classes received none or little information about their low vision students but demonstrated interest in its obtention. It was also shown that those teachers are not prepared to work with visually impaired children.