2,840 research outputs found
Análise rápida do uso da terra em região tradicional de cana-de-açúcar do estado de Alagoas.
O trabalho teve como objetivo levantar e analisar preliminarmente possíveis mudanças de uso da terra nos municípios de cultivo tradicional de cana-de-açúcar, bem como do seu entorno, dentro do estado de Alagoas. Foram levantados dados secundários de fontes oficiais e consultas bibliográficas, sendo avaliada a área plantada (ha) com: a) a cana-de-açúcar e b) milho + mandioca + feijão, no período de 2002 e 2007. Os resultados permitem inferir que as alterações no uso da terra são constantes dentro de Alagoas. Entretanto, ainda são necessários estudos mais aprofundados para se afirmar com propriedade à situação real de possível competição entre a cultura da cana-de-açúcar e a produção de alimentos, bem como sua relação com as áreas de pastagens, em Alagoas
Estimativa de áreas agrícolas utilizando o produto MOD13Q1 em Baturité, Ceará.
Avaliou-se a dinâmica de áreas agrícolas através da classificação por árvore dedecisão entre os anos de 2000 a 2011 no município de Baturité, Estado do Ceará. Foram utilizados o produto MOD13Q1, e o Modelo Digital de Elevação (MDE) gerado a partir dos sensores de radar a bordo do ônibus espacial Endeavour, no projeto SRTM (Shuttle Radar Topography Mission) para montagem da árvore de decisão e classificação das áreas agrícolas de Baturité. O teste Qui-quadrado revelou que o 2 cal χ (1967,93) é superior ao 2 0 χ (19,68) para o intervalo de confiança de α = 5% e 9 graus de liberdade, consequentemente aceita-se a hipótese de nulidade que afirma que os dados observados não são diferentes dos dados estimados. Os resultados obtidos mostram que a técnica da árvore de decisão foi eficaz na determinação das áreas agrícolas em Baturité. A ferramenta poderá dar suporte para levantamentos e planejamentos para tomada de decisões no setor primário (agricultura/pecuária) dos municípios do Ceará
Dados agronômicos de seis genótipos de sorgo (Sorghum bicolor (L.) Moench) para a produção de silagem.
Foram utilizados seis genótipos de sorgo (Sorghum bicolor (L) Moench) de porte alto e colmo seco, colhidos no estádio de grão leitoso/pastoso, com o objetivo de avaliar a altura média das plantas, número de plantas por hectare, proporção panícula/folha/ colmo, dados de produção de matéria verde, matéria seca e matéria seca digestível por hectare. Os híbridos 1 e 2 são as testemunhas comerciais (BRS610 e VOLUMAX, respectivamente), enquanto que os outros quatro são novos materiais desenvolvidos pela EMBRAPA Milho e Sorgo. Utilizou-se o teste SNK para comparação entre médias, com um delineamento experimental inteiramente ao acaso. Houve grande variação no número de plantas por hectare nos genótipos avaliados. Eles não apresentaram diferença estatística na produção de Matéria Verde/hectare. Os híbridos apresentaram correlação positiva entre produção de MS/ha e altura das plantas [r= 0,52 (p= 0,05)]. O híbrido 2 apresentou maior produção de Matéria Seca e Matéria Seca Digestível/ha. Não houve diferença estatística nas proporções de panícula/folha/colmo, com valores que oscilaram de 42,61 a 55,14; 20,75 a 25.73 e 22,85 a 32,75% na MS, respectivamente
Matéria seca, pH e carboidrados sóluveis das silagens de seis genótipos de sorgo (Sorghum bicolor (L.) Moench).
Foram utilizados seis genótipos de sorgo (Sorghum bicolor (L.) Moench) de porte alto e colmo seco com o objetivo de determinar as percentagens de Matéria Seca (MS), de Carboidratos Solúveis (CHOS) e o valor de pH. As silagens foram feitas com sorgo colhido no estádio de grão leitoso/pastoso, em silos de laboratório, feitos de PVC. Os híbridos 1 e 2 são as testemunhas comerciais (BRS610 e VOLUMAX, respectivamente), enquanto que os outros quatro são novos materiais desenvolvidos pela EMBRAPA Milho e Sorgo. Foram avaliados oito períodos, sendo que um destes é a forragem antes de ensilar (PO). Os silos foram abertos com 1; 3; 5; 7; 14; 28 e 56 dias de fermentação. que correspondem a P1; P2; P3; P4; P5; P6 e P7, respectivamente. Utilizou-se o teste SNK para comparação entre médias, com um delineamento experimental inteiramente ao acaso. Houve elevação do teor de MS com o processo de ensilagem. Nas silagens os valores de pH oscilaram de 3,69 a 3,98. De modo geral os híbridos de sorgo apresentaram bom padrão de fermentação, com boa classificação, que variou de boa a muito boa, quanto aos parâmetros utilizados
Portal drained visceral flux, hepatic metabolism, and mammary uptake of free and peptide-bound amino acids and milk amino acid output in dairy cows fed diets containing corn grain steam flaked at 360 orsteam rolled at 490 g/L.
Objectives were to measure net fluxes of free (FAA) and peptide bound amino acids (AA) (PBAA) across portal-drained viscera (PDV), liver, splanchnic, and mammary tissues, and of milk AA output of lactating Holstein cows (n = 6, 109 +/- 9 d in milk) as influenced by flaking density of corn grain. Cows were fed alfalfa-based total mixed ration (TMR) containing 40% steam-flaked (SFC) or steam-rolled corn (SRC) grain. The TMR were offered at 12-h intervals in a crossover design. Six sets of blood samples were obtained from indwelling catheters in portal, hepatic, and mammary veins and mesenteric or costoabdominal arteries every 2 h from each cow and diet. Intake of dry matter (18.4 +/- 0.4 kg/d), N, and net energy for lactation were not altered by corn processing. Milk and milk crude protein yields (kg/12-h sampling) were 14.2 vs. 13.5 and 0.43 vs. 0.39 for cows fed SFC or SRC, respectively. The PDV flux of total essential FAA was greater (571.2 vs. 366.4 g/12 h, SEM 51.4) in cows fed SFC. The PDV flux of total essential PBAA was 69.3 +/- 10.8 and 51.5 +/- 13.2 g/12 h for cows fed SFC and SRC, respectively, and differed from zero, but fluxes of individual PBAA rarely differed between treatments. Liver flux of essential FAA was greater in cows fed SRC, but only the PBAA flux in cows fed SRC differed from zero. Splanchnic flux of FAA and PBAA followed the pattern of PDV flux, but variation was greater. Mammary uptake (g/12 h) of total essential FAA was greater in cows fed SFC than SRC (224.6 vs. 198.3, SEM 7.03). Mammary uptake of essential PBAA was 25.0 vs. 15.1, SEM 5.2, g/12 h for cows fed SFC or SRC, respectively, and differed from zero in half of the PBAA. Milk output of EAA was 187.8 vs 175.4, SEM 4.4 g/12 h in cows fed SFC and SRC, respectively, and output of most essential AA consistently tended to be greater in cows fed SFC. It is apparent that PBAA comprise a portion of total AA flux across PDV and are affected by grain processing. Further, this pool supplies an important component of AA taken up by the mammary gland. Quantifying the contribution of PBAA may improve diet formulation with respect to intestinal absorption and mammary uptake of AA
Search for anomalous t t-bar production in the highly-boosted all-hadronic final state
A search is presented for a massive particle, generically referred to as a
Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are
sufficiently massive to produce highly Lorentz-boosted top quarks, which yield
collimated decay products that are partially or fully merged into single jets.
The analysis uses new methods to analyze jet substructure, providing
suppression of the non-top multijet backgrounds. The analysis is based on a
data sample of proton-proton collisions at a center-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits
in the range of 1 pb are set on the product of the production cross section and
branching fraction for a topcolor Z' modeled for several widths, as well as for
a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any
enhancement in t t-bar production beyond expectations of the standard model for
t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version
includes a minor typo correction that will be submitted as an erratu
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV
The production of b jets in association with a Z/gamma* boson is studied
using proton-proton collisions delivered by the LHC at a centre-of-mass energy
of 7 TeV and recorded by the CMS detector. The inclusive cross section for
Z/gamma* + b-jet production is measured in a sample corresponding to an
integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross
section with Z/gamma* to ll (where ll = ee or mu mu) for events with the
invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level
with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and
the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.)
+(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also
studied and found to be in agreement with the predictions made by the MadGraph
event generator with the parton shower and the hadronisation performed by
PYTHIA.Comment: Submitted to the Journal of High Energy Physic
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy
A search for new physics is performed in events with two same-sign isolated
leptons, hadronic jets, and missing transverse energy in the final state. The
analysis is based on a data sample corresponding to an integrated luminosity of
4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of
7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of
140 increase in integrated luminosity over previously published results. The
observed yields agree with the standard model predictions and thus no evidence
for new physics is found. The observations are used to set upper limits on
possible new physics contributions and to constrain supersymmetric models. To
facilitate the interpretation of the data in a broader range of new physics
scenarios, information on the event selection, detector response, and
efficiencies is provided.Comment: Published in Physical Review Letter
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