Stellar evolution and modelling stars

In this chapter I give an overall description of the structure and evolution of stars of different masses, and review the main ingredients included in state-of-the-art calculations aiming at reproducing observational features. I give particular emphasis to processes where large uncertainties still exist as they have strong impact on stellar properties derived from large compilations of tracks and isochrones, and are therefore of fundamental importance in many fields of astrophysics.Comment: Lecture presented at the IVth Azores International Advanced School in Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in July 201

Canopy characteristics and behavior of Nellore heifers in Brachiaria brizantha pastures under different grazing heights at a continuous stocking rate

The objective of this study was to evaluate the Brachiaria brizantha cv. Marandu canopy structure maintained at different grazing heights under a continuous stocking rate and with a dietary supplementation strategy for the animals during the rainy season. This study also intended to observe the relationships of these variables with the grazing behaviors of the heifers. The effects of three canopy heights (15, 25 and 35 cm) were evaluated in association with three types of supplements: one mineral and two protein/energy supplements, the first with a high rumen degradable protein and energy and the others with a low ratio. Both the protein/energy supplements were provided at 0.3% of body weight/day. The experimental design was completely randomized, with two replications and repeated measures, and took place during the period from January to April 2008. The supplementation strategies did not affect any variable related to the canopy structure. Total and green herbage masses and the ratio of green/dead material increased with canopy height. The leaf/stem ratio was higher in the lowest canopy height: 15 cm. Changes in the canopy structure caused variations in the grazing behavior of the animals. Animals maintained in the 15-cm-tall pasture grazed for a longer time, increasing the time for each meal, but the number of meals was lower than that of the animals grazing within the 35-cm-tall pasture. The grazing time of animals receiving the energy/protein supplement was lower only in the period of the day during which it was supplied. Canopy structure is affected by sward height, and changes animal behavior. Supplementation does not affect the canopy structure of the pastures with similar heights

Sward canopy structure and performance of beef heifers under supplementation in Brachiaria brizantha cv. Marandu pastures maintained with three grazing intensities in a continuous stocking system

The objective of this study was to assess the sward canopy structure of Brachiaria brizantha cv. Marandu pastures maintained in three grazing intensities under continuous stocking system during the rainy season, along with the behavior and performance of grazing beef heifers supplemented with mineral salt or an energy/protein supplement. Three levels of forage allowance were assessed: 2.0, 2.5 and 3.0 kg of forage/kg of live weight, combined with two supplements (ad libitum mineral salt, and an energy/protein supplement at 0.3% of live weight/day, supplied daily). The experiment was designed as a randomized block study with two replications. The supplements did not influence the variables related to the canopy structure. Canopy height was greater at higher forage allowances during the late summer and early fall. Similarly, the stem mass was greater in pastures with higher forage allowances. Animals fed protein supplement spent less time grazing than animals supplemented with mineral salt. Stocking rate was higher in pastures with lower forage allowance levels, which increased the live weight gain per grazing area. Daily weight gain did not vary according to the forage allowance levels. The use of an energy/protein supplement did not affect the stocking rate; however, it increased individual live weight gain and live weight gain per grazing area compared with mineral salt supplementation. The use of energy/protein supplements is an efficient alternative to enhance animal performance and production under grazing systems during the rainy seaso

Suplementação como estratégia de produção de carne de qualidade em pastagens tropicais

O manejo do pastejo e a suplementação estratégica permitem maximizar a produção de carne bovina em pastagens de forma sustentável. A intensidade de pastejo influencia diretamente o crescimento individual, taxas de aparecimento e mortalidade de perfilhos, a determinar o acúmulo de forragem e a estrutura do dossel. Dessa forma, nas águas, é função do manejo do pastejo adequar a frequência e intensidade de desfolhação para que o animal possa colher forragem com idade fisiológica e valor nutritivo adequados. A idade e tamanho dos perfilhos determinam a proporção de tecidos de suporte lignificados que reduzem a digestibilidade da forragem. No período seco, o manejo do pasto e a estratégia de diferimento, ao final do período das águas, são determinantes na obtenção de forragem de melhor valor nutritivo. Assim, o manejo das pastagens visa, primeiramente, à produção de forragens com altos teores de fibra potencialmente digestíveis. A partir de então, a caracterização da quantidade e qualidade da forragem são primordiais à adequação dos nutrientes fornecidos, via suplementos, para otimizar a utilização dos recursos forrageiros basais. A suplementação da dieta dos animais em pastejo, com concentrado, permite aumentar o desempenho dos animais, o que reduz a idade de abate e melhora a qualidade da carcaça e da carne obtida, além dos benefícios na preparação dos animais terminados em confinamento. Portanto, o manejo do pastejo e a suplementação da dieta dos animais permitem aumento de produtividade e maior qualidade dos produtos.Grazing management and strategic supplementation can maximize the production of beef cattle on pastures in a sustainable system. Grazing intensity affects directly on individual growth, appearance and mortality rate of tillers, and also determines the herbage accumulation and canopy structure. During the rainy season is a function of grazing management to adapt the frequency and intensity of defoliation, to supply the animal with forage in an appropriate physiological stage and nutritive value. The age and size of tillers determine the proportion of lignified tissues that will reduce the digestibility of forage. During dry season, the stockpiled pasture strategies at the end of the rainy season, will be crucial to obtaining forage of highest nutritive value. The pasture management primarily aims to produce forages with high levels of potentially digestible fiber. Since then, the characterization of the forage quantity and quality are essential to adjusting the nutrients supplied by supplements to optimize the available forage utilization. Supplementation of grazing beef cattle with concentrate can increase animal performance, reduce the slaughter age, and improve the quality of carcass and meat. Moreover, it has benefits in the preparation of the animals that will be finished in feedlot, and reducing this phase. Therefore, grazing management and supplementation of the animal diet should increase productivity, and improved carcass and beef quality.Universidade Estadual Paulista Faculdade de Ciências Agrárias e VeterináriaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinária Programa de Pós Graduação em ZootecniaUniversidade Federal de Lavras (UFLA) Departamento de ZootecniaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e VeterináriaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinária Programa de Pós Graduação em Zootecni

Doenças de bovinos no Sul do Brasil: 6.706 casos

As doenças que acometem bovinos na região Sul do Brasil foram analisadas através de um estudo dos protocolos de necropsia de 6.706 bovinos examinados pelo Laboratório de Patologia Veterinária da Universidade Federal de Santa (LPV-UFSM), Rio Grande do Sul, de 1964-2008. Desses, 20,9% foram necropsias realizadas no LPV-UFSM e 79,1% foram amostras de tecidos submetidos por veterinários de campo. Dos 6.706 exames, 62,9% tinham diagnóstico conclusivo. A autólise ou material insuficiente foram as principais razões para a ocorrência de casos com diagnóstico inconclusivo. A intoxicação por Senecio spp. foi a principal causa de morte de bovinos neste estudo. As plantas tóxicas e as toxiinfecções juntas, responderam por 22,8% dos casos com diagnóstico conclusivo. As doenças inflamatórias e as parasitoses juntas contribuíram com mais de 30% das doenças de bovinos e a tristeza parasitária bovina foi a principal doença nessa categoria. As demais categorias distribuíram-se na seguinte ordem: neoplasmas e lesões tumoriformes (13,87%), doenças causadas por agentes físicos (2,7%), doenças metabólicas e nutricionais (2,46%), distúrbios circulatórios (1,4%), doenças degenerativas (1,1%), distúrbios do desenvolvimento (0,54%), distúrbios iatrogênicos (0,16%), distúrbios imunogênicos (0,19%) e, outros distúrbios (0,21%). A alta prevalência de tumores em bovinos foi atribuída a ingestão crônica de Pteridium aquilinum, uma toxicose comum na região. As principais doenças de bovinos na região estudada estão relacionadas a fatores ambientais resultante do manejo característico de criação predominantemente extensiva adotado na região.The diseases affecting cattle in southern Brazil were studied through a review of the necropsy reports filed at the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria (LPV-UFSM), Rio Grande do Sul, and pertaining to the examination of 6.076 cattle during 1964-2008. Of those exams 29.9% were necropsies performed at the LPV-UFSM and 79.1% were mailed-in organ fragments from necropsies performed at the field by veterinary practitioners. Autolysis and non-representative sampling o mailed in organs were the main reasons for non-conclusive diagnosis. Poisoning by Senecio spp. was the main cause of death in cattle in this study and poisonous plants together with toxi-infections accounted for 22.8% of the cases with conclusive diagnosis. Inflammatory diseases together with parasitic diseases accounted for more than 30% of cattle diseases and babesiosis and anaplasmosis were the main diseases in this category. Other categories were distributed in the following order: neoplasms and tumor-like lesions (13.87%), diseases caused by physical agents (2.7%), metabolic and nutritional diseases (2.46%), circulatory disturbances (1.4%), degenerative diseases (1.1%), developmental disorders (0.54%), iatrogenic diseases and sundry lesions. The high prevalence of tumors in cattle in this study was attributed to the chronic ingestion of Pteridium aquilinum, a common toxicosis in the region. The main diseases in cattle from the studied region are related to environmental factors associated to the predominantly husbandry practices adopted in the region

Suplementação protéica energética no desempenho de novilhas em pastejo durante a fase de terminação

Para estudar o efeito da suplementação da dieta sobre o desempenho de novilhas na fase de terminação mantidas em pastagem de capim-marandu sob lotação intermitente, durante a estação chuvosa, foram utilizadas 20 novilhas cruzadas (¼ Nelore, ¼ Santa Gertrudes, ½ Braunvieh) com peso corporal médio de 300 kg e 22 meses de idade. Os tratamentos constituíram-se de dois tipos de suplementação: sal mineral (SM) ad libtum e suplemento protéico energético (SPE) fornecido a 0,3% do peso corporal (PC) por dia com avaliações realizadas a cada 28 dias, no período entre dezembro de 2006 e março de 2007 Foram avaliados o desempenho animal e as características de carcaça medidas por ultrassom. Observou-se o efeito (P=0,057) da suplementação sobre o ganho de peso dos animais suplementados, 0,700 kg/dia e 0,587 kg/dia dos animais que receberam sal-mineral. Houve efeito da suplementação na área de olho de lombo e profundidade do músculo Gluteus medius. As demais características analisadas pela técnica de ultrassom não diferiram entre si em função da suplementação. A suplementação protéica energética da dieta permite ganhos adicionais, o que reflete em aumento da deposição de músculo de novilhas mantidas em pastagem de capim-marandu durante o período das águas.This study was conducted to evaluate the effect of the diet supplementation on the heifers performance in finishing phase, maintained in a marandu grass pasture managed in intermittent grazing system during the rainy season. Twenty crossbreed (¼ Nelore, ¼ Santa Gertrudes, ½ Braunvieh) heifers with average initial body weight of 300 kg and 22 months old were used. The treatments consisted of two types of supplements: mineral (SM) ad libtum and energy protein supplementation (PES) provided 0.3% of the body weight daily. The evaluated variables were: animal performance and carcass traits measured by ultrasound each 28 days. Supplementation affected daily weight gain (P=0.057), 0.700 kg/day for supplemented animals against 0.587 kg/day for animals receiving salt-mineral. There were no supplementation effect on the loin eye area and depth of the Gluteus medius muscle. The other characteristics examined by the ultrasound technique did not differ according to the treatments. Protein and energy supplementation of the diet allows additional gains that reflected in increased deposition of muscle of heifers grazing marandu grass during the wet season