Comportamento de sementes de jambu (Spilanthes oleracea L.) no armazenamento.

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Armazenamento de sementes de mangostão.

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Levantamento florístico da regeneração natural em área de várzea do Rio Guamá, Estado do Pará.

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Jet quenching with running coupling including radiative and collisional energy losses

We calculate the nuclear modification factor for RHIC and LHC conditions accounting for the radiative and collisional parton energy loss with the running coupling constant.We find that the RHIC data can be explained both in the scenario with the chemically equilibrium quark-gluon plasma and purely gluonic plasma with slightly different thermal suppression of the coupling constant. The role of the parton energy gain due to gluon absorption is also investigated. Our results show that the energy gain gives negligible effect.Comment: 11 pages, 3 figure

Levantamento florístico em área de cultivo de arroz irrigado em várzea do rio Guamá - Estado do Pará.

Descreveu-se a composição florística de uma área amostrada de 44 m2 de várzea do rio Guamá, objetivando reunir informações sobre espécies que poderão causar problemas de infestação em cultivos de arroz irrigado. O levantamento foi efetuado em uma área 1,2 ha, em pousio, ha cerca de dois anos após o cultivo do arroz, constituída de seis tabuleiros de 2.090 m2, dispostos um ao lado do outro ao longo de um canal de irrigação. Cada tabuleiro foi dividido em oito parcelas de 243 m2 e a amostragem foi ao acaso, identificando-se todas as plantas contidas em cada amostra de 1m2. Concluiu-se que: as espécies Rhynchospora corymbosa Hitchcock, Eriochloa polystachya H.B. & K. e Commelina longicaulis Hort. Berol. foram as mais abundantes e frequentes (30,95 plantas/m2, 19,70 plantas/m2, 7,73 plantas/m2 e 18,23, 8,84 e 11,05%, respectivamente). Aos dois anos de sucessão vegetal, a abundância de plantas monocotiledoneas e superior as dicotiledoneas, portanto sugere-se que nos estádios iniciais da cultura do arroz irrigado seja feito um controle sobre essa classe de plantas daninhas; a água de irrigação tem função importante como meio de dispersão de plantas e a infestação ocorreu em maior intensidade em locais próximos a fonte de irrigação; a amostragem de 33% da área total foi adequada par obter-se uma amostra representativa da vegetação.bitstream/item/42802/1/Boletim-Pesquisa-173-CPATU.pd

The density, the cosmic microwave background and the proton-to-electron mass ratio in a cloud at redshift 0.9

Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830–211, which is by far the best known target to study dense cool gas in absorption at intermediate redshift. Determining average radial velocities and performing Large Velocity Gradient radiative transfer calculations, the aims of this study are (1) to determine the density of the gas, (2) to constrain the temperature of the cosmic microwave background (CMB), and (3) to evaluate the proton-to-electron mass ratio at redshift z ∼ 0.89. Analyzing data from six rotational HC_3N transitions (this includes the J = 7 ← 6 line, which is likely detected for the first time in the interstellar medium) we obtain n(H_2) ∼ 2600 cm^(−3) for the gas density of the south-western absorption component, assuming a background source covering factor, which is independent of frequency. With a possibly more realistic frequency dependence proportional to ν^(0.5) (the maximal exponent permitted by observational boundary conditions), n(H2) ∼ 1700 cm^(−3). Again toward the south-western source, excitation temperatures of molecular species with optically thin lines and higher rotational constants are, on average, consistent with the expected temperature of the cosmic microwave background, T^(CMB) = 5.14 K. However, individually, there is a surprisingly large scatter which far surpasses expected uncertainties. A comparison of CS J = 1 ← 0 and 4 ← 3 optical depths toward the weaker north-western absorption component results in T_(ex) = 11 K and a 1-σ error of 3 K. For the main component, a comparison of velocities determined from ten optically thin NH_3 inversion lines with those from five optically thin rotational transitions of HC_3N, observed at similar frequencies, constrains potential variations of the proton-to-electron mass ratio μ to Δμ/μ < 1.4 × 10^(−6) with 3-σ confidence. Also including optically thin rotational lines from other molecular species, it is emphasized that systematic errors are ΔV < 1 kms^(−1), corresponding to Δμ/μ < 1.0 × 10^(−6)

Elastic anomalies in HoNi2B2C single crystals

We have measured temperature and magnetic field dependencies of the sound velocities and the sound attenuation in HoNi2B2C single crystals. The main result is a huge softening the velocity of C66 mode due to a cooperative Jahn-Teller effect, resulting in a tetragonal-orthorhombic structural phase transition. Anomalies in the behavior of the C66 mode through various magnetic phase transitions permit us to revise the low temperature H-T phase diagrams of this compound.Comment: v2: a discussion of the C44 mode with the comparison to Y borocarbide was adde

Renormalization of heavy-light currents in moving NRQCD

Heavy-light decays such as $B \to \pi \ell \nu$, $B \to K^{*} \gamma$ and $B \to K^{(*)} \ell \ell$ can be used to constrain the parameters of the Standard Model and in indirect searches for new physics. While the precision of experimental results has improved over the last years this has still to be matched by equally precise theoretical predictions. The calculation of heavy-light form factors is currently carried out in lattice QCD. Due to its small Compton wavelength we discretize the heavy quark in an effective non-relativistic theory. By formulating the theory in a moving frame of reference discretization errors in the final state are reduced at large recoil. Over the last years the formalism has been improved and tested extensively. Systematic uncertainties are reduced by renormalizing the m(oving)NRQCD action and heavy-light decay operators. The theory differs from QCD only for large loop momenta at the order of the lattice cutoff and the calculation can be carried out in perturbation theory as an expansion in the strong coupling constant. In this paper we calculate the one loop corrections to the heavy-light vector and tensor operator. Due to the complexity of the action the generation of lattice Feynman rules is automated and loop integrals are solved by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and ultraviolet divergences in the loop integrals both in the continuum and on the lattice. The light quarks are discretized in the ASQTad and highly improved staggered quark (HISQ) action; the formalism is easily extended to other quark actions.Comment: 24 pages, 11 figures. Published in Phys. Rev. D. Corrected a typo in eqn. (51

Metallicity and Physical Conditions in the Magellanic Bridge

We present a new analysis of the diffuse gas in the Magellanic Bridge (RA>3h) based on HST/STIS E140M and FUSE spectra of 2 early-type stars lying within the Bridge and a QSO behind it. We derive the column densities of HI (from Ly\alpha), NI, OI, ArI, SiII, SII, and FeII of the gas in the Bridge. Using the atomic species, we determine the first gas-phase metallicity of the Magellanic Bridge, [Z/H]=-1.02+/-0.07 toward one sightline, and -1.7<[Z/H]<-0.9 toward the other one, a factor 2 or more smaller than the present-day SMC metallicity. Using the metallicity and N(HI), we show that the Bridge gas along our three lines of sight is ~70-90% ionized, despite high HI columns, logN(HI)=19.6-20.1. Possible sources for the ongoing ionization are certainly the hot stars within the Bridge, hot gas (revealed by OVI absorption), and leaking photons from the SMC and LMC. From the analysis of CII*, we deduce that the overall density of the Bridge must be low (<0.03-0.1 cm^-3). We argue that our findings combined with other recent observational results should motivate new models of the evolution of the SMC-LMC-Galaxy system.Comment: Accepted for publication in the Ap