Produção de mudas de caramboleiras 'B-10' e 'Golden Star': II. Marcha de absorção e acúmulo de nutrientes.

A participação do Brasil no mercado externo de frutas tem aumentado consideravelmente e com potencial para crescer ainda mais. A constante ascensão dos dados de exportação brasileira é resultado da combinação de avanços tecnológicos do setor produtivo e de acesso a novos mercados consumidores. A caramboleira apresenta-se como uma excelente opção de cultivo de frutas exóticas, com grande potencial para atender ao mercado interno e às exportações. Assim, objetivou-se avaliar a marcha de absorção e de acúmulo de nutrientes em mudas de caramboleiras cultivadas em solução nutritiva. O experimento foi realizado em parcelas subdivididas, sendo utilizadas como parcela as duas cultivares de caramboleira (?B-10? e ?Golden Star?) e, como subparcelas, cinco épocas de coleta de plantas, realizadas aos 208; 233; 258; 283 e 308 dias após o transplantio para a solução nutritiva. O delineamento foi inteiramente casualizado, com três repetições. As mudas foram cultivadas em vasos (8L) com solução nutritiva (pH=5,5 ± 0,5), com aeração. O experimento iniciou-se em 24-08-2005. Nos diferentes órgãos das mudas (folhas, caule e raízes), determinaram-se a marcha de absorção, o acúmulo de nutrientes e os índices nutricionais. Não houve diferenças no acúmulo de nutrientes entre as mudas de caramboleira de ambas as cultivares, sendo a ordem decrescente dos nutrientes em cada muda de ?B-10?, no final do período experimental: N > K > Ca > Mg > S > P > Fe > Mn > B > Cu > Zn. Para a ?Golden Star?, a ordem foi: N > K > Ca > Mg > P > S > Fe > Mn > B > Cu > Zn. Para as duas cultivares, o acúmulo médio foi maior nas folhas > caule > raízes. O período de maior exigência para ?B-10? foi entre 208 ? 233 e, para ?Golden Star?, entre 233 ? 283 dias após o transplantio. As diferentes taxas de acumulação líquida dos nutrientes, nos diferentes órgãos da caramboleira, nem sempre acompanharam a taxa de acumulação de nutrientes do respectivo órgão. Production of star fruit ?B-10? and ?Golden Star? seedlings: II ? Absorption rate and acumulation of nutrients. Abstract ? Brazil?s participation in the external market of fruits has increased considerably with the potential to grow further. The constant rise of the Brazilian exportation data is the result of a combination of technological advances in the productive sector and access to new markets. The star fruit is presented as an excellent option for cultivation of exotic fruits, with great potential to attend the domestic market and exportation. Thus, the objective was to assess absorption rate and accumulation of nutrients in star fruit seedlings, grown in nutrient solution. The experiment was conducted in split plots being used as part of the two cultivars of star fruit (?B-10? and ?Golden Star?) and as subplots, five plant collecting periods, realized at 208, 233, 258, 283 and 308 days after transplanting to the nutrient solution. The experimental design was completely randomized with three replications. The seedlings were grown in pots (8L) with nutrient solution (pH = 5.5 ± 0.5) with aeration. The experiment started on 08.24.2005. In different plant organs (leaves, stems and roots), absorption rate, accumulation of nutrients and nutritional indices were determined. It did not have differences in the accumulation of nutrients in the star fruit seedlings for both cultivars, the decreasing order of the nutrients in each ?B-10?seedlings, in the end of the experimental period, was: N > K > Ca > Mg > S > P > Fe > Mn > B > Cu > Zn. For ?Golden Star? the decreasing order was: N > K > Ca > Mg > P > S > Fe > Mn > B > Cu > Zn. For the two cultivars, the average accumulation was bigger in leaves > stem > roots. The period of bigger requirement for ?B-10? was between 208 - 233 and, for ?Golden Star?, between 233 - 283 days after the transplantation. The different rates of nutrient liquid accumulation, in the different organs of star fruit trees, not always followed the nutrient accumulation rate of the respective organ

The silicon multiplicity detector for the NA50 experiment at CERN

The design, operation and performance of the silicon strip Multiplicity Detector for the heavy-ion experiment NA50 at CERN are presented. The main features of the detector are high speed (50 MHz sampling frequency), high granularity (more than 13,000 strips), and good radiation resistance. The detector provided a measurement ofevent centrality in Pb–Pb collisions, as well as target identification and the measurement ofcharged particle pseudorapidity distributions as a function of centrality. r 2002 Elsevier Science B.V. All rights reserved. PACS: 29.4

Desempenho de variedades de milho: ano agrícola 2008/09.

bitstream/item/26808/1/CT-182.pd

Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure

A search for W bb and W Higgs production in ppbar collisions at sqrt(s)=1.96 TeV

We present a search for W b \bar{b} production in p \bar{p} collisions at sqrt{s}=1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity accumulated by the D0 experiment at the Fermilab Tevatron collider, and the standard-model description of such events, we set a 95% C.L. upper limit on W b \bar{b}$production of 6.6 pb for b quarks with transverse momenta p_T^b > 20 GeV and b \bar{b} separation in pseudorapidity-azimuth space Delta R_bb > 0.75. Restricting the search to optimized b \bar{b} mass intervals provides upper limits on$WH$production of 9.0$-$12.2 pb, for Higgs-boson masses of 105$-$135 GeV.Comment: 7 pages, 4 figures, 1 table, submitted to Physical Review Letter