609 research outputs found

    Application of a thermolysis capacity test for dry and lactating cows

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    The heat stress has negative effects on animal comfort and productivity. Genetic progress in milk production is related closely to an increase in metabolic heat increment, which makes cows more affected by heat stress. Individual thermotolerance can be an important tool in genetic selection. The study aimed to validate a new proposal for assessing the ability of heat loss after sun exposure in cows and its application in dry and lactating cows kept or not on thermal comfort condition. The test consists in three days of sun exposure for one hour followed by one hour rest in the shade to determine the individual thermolysis capacity (TC) by the variables rectal temperature, body surface temperature, internal tail base temperature, respiratory rate, plasma cortisol and IGF-I. In the new proposal these physiological variables were measured before sun exposure, after 50 min in the sun and after one hour in the shade (T0, T1 and T2 consecutively). The test in which this new test was adapted lacked T1.The three day test was applied with similar meteorological variables as black globe temperature of 48.1°C (1.32), air temperature of 31.7°C (0.92) and relative humidity of 39.5% (3.38). The differences between dry and lactating cows were measured in 28 animals divided into two experimental groups housed in free-stall with and without evaporative cooling system (mist and fans). The animals remained at the facility for seven months (from spring to summer) then after they were subjected to heat stress and the TC (10-[(T1-T0)-(T2-T1)]) was determined. There was no difference between the TC of dry and lactating cows (P>0.05), but respiratory rate and IGF-I were greater and body surface was lower in dry cows during sun exposure (P0.05). The thermolysis capacity test was validated and can be used for either dry or lactating cows. Milk production did not influence the thermoregulatory responses of Holstein cows, but when lactating and kept in cooling system they showed better thermolysis capacity index

    Reactivity in ewes submitted to invasive and non-invasive techniques of samples collections

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    The first-time experience of a procedure or with a person should be as positive as possible. If a procedure is very aversive or painful at first contact, it can be difficult to persuade the animal to return to the local where this occurred. For this reason it is important to develop a strategy in experimental and routine activities, taking into account that sheep has often reactive temperament. This study aims to evaluate the possible decreased of the reactivity in sheep across the prior presentation of invasive and non-invasive techniques for collecting saliva and blood samples for cortisol analysis and transepidermal water loss through the use of Vapometer®. Saliva was collected using Sallivetes® and blood was taken from the jugular vein in heparinized tubes, placed on ice, and then centrifuged at 4 °C and 3,000 for 15 min. The tubes containing serum were stored at −20 °C until CORT and IGF-I determination using an enzyme immunoassay kit (Diagnostic Systems Laboratory, Webster, TX). The collection of transepidermal water loss (TEWL) was performed using a Vapometer ® (Dolphin, Finland) device. In the three techniques the ewes were always contained by the same person for the time necessary to collect the variable. To take saliva samples the animals were contained during 2 minutes, for blood samples during 1 minute and for TEWL during 30 seconds. The test consists of six data collections performed with increasing intervals between days, checking the possible adaptation of the animal management factors. The first interval was 2 days and after 3 days, then after 4 days, and the next was 7 days and again 7 days, totaling 24 days of experiment. Before sampling saliva, blood or TEWL the reactivity of the ewes was analyzed by a composite score scale when animals were inside the chute. The composite score (CS) is a combination of the scores of: entrance (1 to 4), respiratory rate (1 to 4), vocalization (0 or 1), movement (1 to 4) and flight speed (1 to 4). After the chute a score of containment (1 to 4) was attributed by the same person, which had contained the animal. The experimental unit was each animal and the average of the observations in each sheep was used for the statistical analysis. The observed data of transepidermal water loss, salivary cortisol and serum cortisol were subjected to analysis of variance, with the days and the groups as fixed effect. In case of significant results (P<0.05) it was adopted Tukey-Kramer Test as the procedure for multiple comparisons. Cortisol decreased for saliva and blood groups during the experiment days (P<0.05), showing habituation of the animals to the management. In the same way, TEWL had the highest mean value on day 1, and decreased afterwards (P<0.05). The score of containment was lower for the TEWL group compared to the other two groups (P<0.05), however the higher value was observed on day 5, seven days after a sampling (P<0.05). The score of containment of saliva and blood groups decrease in day 2, but return to increase in the next sampling day (P<0.05). The CS was higher for saliva group (P<0.05). On day 5 CS increased for blood group, but decreased for TEWL (P<0.05). The invasive techniques (saliva and blood) increased the reactivity of sheep before and after retention. Sheep are reactive animals therefore need a more gentle handling during the experiment with invasive samples

    Avaliação do curso de Engenharia Florestal

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    O relatório resulta do trabalho de avaliação ao curso de Engenharia Florestal levado a cabo pela equipa de Auto-Avaliação da Escola Superior Agråria de Castelo Branco. Esta equipa, designada pelo conselho científico com a finalidade de proceder a todas as solicitaçþes de avaliação tanto dos cursos como da instituição, Ê basicamente composta por um coordenador e um elemento de cada unidade departamental. Decorrente do tipo de curso que se estå a avaliar juntam-se à equipa os respectivos coordenadores do curso e um relator. AlÊm deste elementos participaram tambÊm neste trabalho um representante dos alunos (designado pela associação de estudantes) e dois funcionårios representantes do pessoal administrativo e do pessoal não docente. Em termos metodológicos optou-se pelo seguimento do guião proposto pelo CNAVES, tendo-se recolhido informação de diversos modos: pesquisa documental e bases de dados nos serviços administrativos, inquÊritos auto administrados a alunos, docentes e funcionårios, inquÊrito postal aos diplomados e entrevistas directas às entidades empregadoras. Uma vez recolhida e tratada a informação procedeu-se à sua anålise crítica tendo como referência os trabalhos de avaliação que atÊ então decorreram relativamente à Escola e ao curso de Produção Florestal que antecedeu o actual curso de Engenharia Florestal

    Evaluation of buriti endocarp as lignocellulosic substrate for second generation ethanol production

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    The production of lignocellulosic ethanol is one of the most promising alternatives to fossil fuels; however, this technology still faces many challenges related to the viability of the lignocellulosic alcohol in the market. In this paper the endocarp of buriti fruit was assessed for ethanol production. The fruit endocarp was characterized physically and chemically. Acid and alkaline pre-treatments were optimized by surface response methodology for removal of hemicellulose and lignin from the biomass. Hemicellulose content was reduced by 88% after acid pretreatment. Alkaline pre-treatment reduced the lignin content in the recovered biomass from 11.8% to 4.2% and increased the concentration of the cellulosic fraction to 88.5%. The pre-treated biomass was saccharified by the action of cellulolytic enzymes and, under optimized conditions, was able to produce 110 g of glucose per L of hydrolyzate. Alcoholic fermentation of the enzymatic hydrolyzate performed by Saccharomyces cerevisiae resulted in a fermented medium with 4.3% ethanol and a yield of product per substrate (YP/S) of 0.33

    Influência do aumento da concentração do CO2 atmosfÊrico e da temperatura do ar no desenvolvimento da cultura do cafÊ

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    O clima condiciona fortemente a produtividade agrícola e mesmo alteraçþes moderadas a severas das condiçþes ambientais poderão afetar a produção, levando a perdas económicas e impactos sociais. O previsível aumento da concentração de CO2 atmosfÊrico, associado a alteraçþes nos padrþes de pluviosidade, ao aumento na duração e intensidade da seca, bem como a um aumento generalizado das temperaturas, são realidades cada vez mais presentes em todos os cenårios agrícolas. As interaçþes complexas entre estes diferentes fatores alterarão as respostas das plantas com potencial impacto acrescido na produtividade e qualidade dos produtos finais. O aumento da concentração atmosfÊrica de diferentes gases com efeito de estufa, com destaque para o CO2, tem ocorrido em simultâneo com o aumento da temperatura do ar. Desde o início da revolução industrial no sÊc. XVIII, a concentração de CO2 aumentou de ca. 280 ΟL CO2 L-1, tendo ultrapassado 400 ΟL CO2 L-1 em 2013, sendo previsível que possa atingir valores entre 421 e 936 ΟL CO2 L-1 no final do sÊculo. Adicionalmente, previsþes recentes para este sÊculo apontam para aumentos da temperatura ao nível da superfície do planeta que poderão ir de 0,3-1,7 ºC, atÊ um extremo de 2,6-4,8 ºC. Este eventual aumento de temperatura levarå a alteraçþes dråsticas nos teores de humidade do ar e consequentemente nos regimes de pluviosidade. Estas circunstâncias poderão promover condiçþes de seca mais frequentes e extremas. Contrastando com o impacto negativo da redução da disponibilidade hídrica ou do aumento da temperatura, o aumento do valor de CO2 per se pode ter um papel positivo, pois estimula a produção. A cultura do cafÊ Ê uma das mais importantes culturas de rendimento do mundo, estando presente em mais de 80 países da região tropical e sendo suportada por 2 espÊcies, Coffea arabica L. (cafÊ tipo Aråbica) e Coffea canephora Pierre ex A. Froehner, (cafÊ tipo Robusta). Neste contexto torna-se premente o estudo dos mecanismos (com destaque para os ecofisiológicos) envolvidos na aclimatação das plantas, a um ambiente em permanente mudança. Recentes projeçþes indicam perdas significativas da årea de cultivo de Coffea sp (particularmente de C. arabica), mas estudos recentes mostraram que o aumento dos valores de CO2 na atmosfera têm um efeito claramente mitigador do impacto de temperaturas supra-óptimas, moderando os impactos antes estimados com base em modelos que não têm em linha de conta este efeito benÊfico do CO2. O conhecimento proveniente de estudos multidisciplinares e a obtenção de indicadores ecofisiológicos auxiliarå na seleção de indivíduos mais tolerantes e servirå de ferramentas para o melhoramento de novas plantas com uma maior capacidade de adaptação.info:eu-repo/semantics/publishedVersio

    Percepção ambiental dos produtores e qualidade do solo em propriedades orgânicas e convencionais.

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    O sistema orgânico de produção deve resultar na utilização mais racional dos recursos naturais, sobretudo do solo. Os produtores orgânicos devem adotar pråticas conservacionistas, alÊm de atender a outros princípios deste sistema de produção. Neste trabalho foram avaliadas as pråticas de manejo e conservação do solo adotadas por produtores orgânicos e convencionais nas regiþes dos municípios de Socorro (Serra da Mantiqueira e Mogiana) e Ibiúna, situados no Estado de São Paulo. O objetivo dessa pesquisa foi verificar o grau de adoção de pråticas conservacionistas pelos produtores e avaliar a qualidade do solo na agricultura orgânica e convencional. Foi elaborado e aplicado um questionårio, com visitas locais para verificação das pråticas conservacionistas e ocorrência de erosão, em 30 propriedades. Os resultados foram expressos em índices indicadores de diversidade de uso do solo, atitude conservacionista, percepção de erosão e do impacto sobre os recursos hídricos. Foram tambÊm realizadas anålises de atributos químicos, físicos e biológicos indicadores da qualidade do solo. Concluiu-se que os produtores orgânicos têm maior percepção quanto à atitude conservacionista e nas propriedades orgânicas hå maior diversidade de cultivos, embora não haja maior diversidade geral de uso do solo. A produção orgânica de alface, em Ibiúna proporcionou maior atividade biológica no solo e maior colonização por fungos micorrízicos arbusculares. O sistema orgânico possui maiores teores de matÊria orgânica e menores de potåssio e não houve diferença entre os atributos físicos do solo dos sistemas orgânico e convencional

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

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    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg⁡(E/eV)=18.5−19.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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