Nutrição mineral de hortaliças: XXIV - carência de macronutrientes em berinjela (Solanum melongena L.)

Plantas de berinjela (Solanum melongena L. var. Híbrida F1, Piracicaba nº 100) foram cultivadas em vasos contendo sílica lavada. As plantas foram irrigadas com solução nutritiva purificada e submetidas aos seguintes tratamentos: completo, omissão de B, Cu, Fe, Mn, Mo e Zn. Os sintomas de carência desses elementos foram identificados e descritos. Aquilatou-se a possibilidade de recuperação de plantas deficientes fornecendo-se o elemento. Finalmente, as plantas foram separadas em: raiz, caule superior e inferior, folhas velhas e novas, frutos, e analisadas para B, Cu, Fe, Mn e Zn. A análise química das folhas afetadas pelas carências apresentou os seguintes valores (ppm): B- 48-71; Cu- 1-2; Fe- 169-204; Mn- .42-80; Zn- 37-38. Nas folhas sadias os valores foram (ppm): B- 70-82; Cu- 8; Fe- 192-283; Mn- 54-118; Zn- 52-54.Eggplants were grown in pots containing 7 kg of pure quartz sand. Twice a day they were irrigated by percolation with nutrient solutions. The treatments were: complete, -B, -Cu, -Fe, -Mn, -Zn. The deficiencies symptoms are described. The deficiencies were comproved by chemical analysis of the different parts of the plants. The following concentration, expressed in ppm in dry matter are

Determining the density of states for classical statistical models: A random walk algorithm to produce a flat histogram

We describe an efficient Monte Carlo algorithm using a random walk in energy space to obtain a very accurate estimate of the density of states for classical statistical models. The density of states is modified at each step when the energy level is visited to produce a flat histogram. By carefully controlling the modification factor, we allow the density of states to converge to the true value very quickly, even for large systems. This algorithm is especially useful for complex systems with a rough landscape since all possible energy levels are visited with the same probability. In this paper, we apply our algorithm to both 1st and 2nd order phase transitions to demonstrate its efficiency and accuracy. We obtained direct simulational estimates for the density of states for two-dimensional ten-state Potts models on lattices up to $200 \times 200$ and Ising models on lattices up to $256 \times 256$. Applying this approach to a 3D $\pm J$ spin glass model we estimate the internal energy and entropy at zero temperature; and, using a two-dimensional random walk in energy and order-parameter space, we obtain the (rough) canonical distribution and energy landscape in order-parameter space. Preliminary data suggest that the glass transition temperature is about 1.2 and that better estimates can be obtained with more extensive application of the method.Comment: 22 pages (figures included

Measuring CMB Polarization with BOOMERANG

BOOMERANG is a balloon-borne telescope designed for long duration (LDB) flights around Antarctica. The second LDB Flight of BOOMERANG took place in January 2003. The primary goal of this flight was to measure the polarization of the CMB. The receiver uses polarization sensitive bolometers at 145 GHz. Polarizing grids provide polarization sensitivity at 245 and 345 GHz. We describe the BOOMERANG telescope noting changes made for 2003 LDB flight, and discuss some of the issues involved in the measurement of polarization with bolometers. Lastly, we report on the 2003 flight and provide an estimate of the expected results.Comment: 12 pages, 8 figures, To be published in the proceedings of "The Cosmic Microwave Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and K.A. Olive). Fixed typos, and reformatted citation

Spanning forests and the q-state Potts model in the limit q \to 0

We study the q-state Potts model with nearest-neighbor coupling v=e^{\beta J}-1 in the limit q,v \to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the Potts-model phase diagram in the neighborhood of (q,v) = (0,0). We have studied this model on the square and triangular lattices, using a transfer-matrix approach at both real and complex values of w. For both lattices, we have computed the symbolic transfer matrices for cylindrical strips of widths 2 \le L \le 10, as well as the limiting curves of partition-function zeros in the complex w-plane. For real w, we find two distinct phases separated by a transition point w=w_0, where w_0 = -1/4 (resp. w_0 = -0.1753 \pm 0.0002) for the square (resp. triangular) lattice. For w > w_0 we find a non-critical disordered phase, while for w < w_0 our results are compatible with a massless Berker-Kadanoff phase with conformal charge c = -2 and leading thermal scaling dimension x_{T,1} = 2 (marginal operator). At w = w_0 we find a "first-order critical point": the first derivative of the free energy is discontinuous at w_0, while the correlation length diverges as w \downarrow w_0 (and is infinite at w = w_0). The critical behavior at w = w_0 seems to be the same for both lattices and it differs from that of the Berker-Kadanoff phase: our results suggest that the conformal charge is c = -1, the leading thermal scaling dimension is x_{T,1} = 0, and the critical exponents are \nu = 1/d = 1/2 and \alpha = 1.Comment: 131 pages (LaTeX2e). Includes tex file, three sty files, and 65 Postscript figures. Also included are Mathematica files forests_sq_2-9P.m and forests_tri_2-9P.m. Final journal versio

Measurement of the p-pbar -> Wgamma + X cross section at sqrt(s) = 1.96 TeV and WWgamma anomalous coupling limits

The WWgamma triple gauge boson coupling parameters are studied using p-pbar -> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were collected with the DO detector from an integrated luminosity of 162 pb^{-1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.Comment: Submitted to Phys. Rev. D Rapid Communication

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events

We present a measurement of the top quark pair ttbar production cross section in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1} of data collected by the DO detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the ttbar content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1} (syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let