DIGESTIBILIDADE DA FRAÇÃO NITROGENADA EM BOVINOS ALIMENTADOS COM RAÇÕES CONTENDO DIFERENTES FONTES DE NITROGENIO

The present research work has been carried out with the aim to study the digestibility of nitrogen fractions, in animals fed with different nitrogen sources rations. The diets were supplied to Holstein steers with abomasal cannulas, with eight months of age and average weight of 187 kg, in a total of 21 animals selected at random. The experimental rations were constituted by 40% roughage (Rhodes grass hay) and 60% concentrate (corn, cotton seed meal, yeast, urea, molasses and minerals) by concentrate mixture. The utilized treatments were: RA (ration with cotton seed meal); RL (ration with yeast); RU (ration with urea). The amount of nitrogen (N) intaked in grams per day (g/day) in relation of metabolic weight (g/kgLW0.75) did not display significant differences (P > 0.05) with the change of nitrogen source of diets. Also the N present in abomasum (g/day) did not display significant differences (P > 0.05). The N apparent digestibility was superior (P < 0.05) in RU diet (53.61%) when compared to RA and RL diets (46.66 and 46.37%, respectively). RA and RL diets, despite presenting the largest amount of NNA in the abomasum (71.75 and 72.38 g/day respectively) in relation to RU diet (P < 0.05), were the ones that present the largest amounts eliminated in feaces as well (37.74 and 41.20 g/day, respectively). This fact contributed for the amounts absorbed of NNA by the intestine (g/day), which did not present significant differences between the diets (P > 0.05). The protein sources of diets intervened on the nitrogen apparent digestibility.O objetivo do presente trabalho foi estudar a digestibilidade da fração nitrogenada em animais alimentados com diferentes fontes de nitrogênio (N). As dietas foram fornecidas a bezerros da raça Holandesa, canulados no abomaso, com idade aproximada de 8 meses e peso médio de 187 kg, totalizando 21 animais escolhidos aleatoriamente, formando o grupo de repetições experimentais. As rações experimentais foram constituídas de 40 % de volumoso (feno de Capim-de-Rhodes) e 60 % de concentrado (milho, farelo de algodão, levedura, uréia, melaço e minerais), sendo: RA: ração com farelo de algodão; RL: ração com levedura; RU: ração com uréia. A quantidade de N ingerido em g/dia e em relação ao peso metabólico não apresentou diferenças significativas (P > 0,05) à medida que se variou a fonte nitrogenada das dietas. O N presente no abomaso (g/ dia) também não apresentou diferenças significativas entre as dietas (P > 0,05). A digestibilidade aparente do N foi superior (P < 0,05) na dieta RU (53,61 %) em relação às dietas RA e RL (46,66 e 46,37 %, respectivamente). As dietas RA e RL, apesar de apresentarem maiores quantidades de nitrogênio não-amoniacol (NNA) presentes no abomaso (71,75 e 72,38 g/dia respectivamente) em relação à dieta RU (P < 0,05), também foram as que apresentaram maiores quantidades eliminadas nas fezes (37,74 e 41,20 g/dia, respectivamente); isto contribuiu para que a quantidade de NNA absorvida no intestino (g/dia) não apresentasse diferenças significativas entre as dietas (P > 0,05). As fontes nitrogenadas das dietas interferiram sobre a digestibilidade aparente do nitrogênio

Soil organisms in organic and conventional cropping systems.

Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas

Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

The $B_s^0\to J/\psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$\beta$ measurement from $B^0\to J/\psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}$. This is the most precise measurement to date

Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201

Absolute luminosity measurements with the LHCb detector at the LHC

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex

Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma

The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x 10^{-5}. The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/- 0.9(syst.))%. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table

Absolute luminosity measurements with the LHCb detector at the LHC

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex

Absolute luminosity measurements with the LHCb detector at the LHC

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex