Ghost poles in the nucleon propagator in the linear sigma model approach and its role in pi N low-energy theorems

Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff and Wilets (BPW), These ghosts violate basic theorems of quantum field theory and their origin is related to the ultraviolet behavior of the model interactions, Recently, Krein et.al, proved that the ghosts disappear when vertex corrections are included in a self-consistent way, softening the interaction sufficiently in the ultraviolet region. In previous studies of pi N scattering using ''dressed'' nucleon propagator and bare vertices, did by Nutt and Wilets in the 70's (NW), it was found that if these poles are explicitly included, the value of the isospin-even amplitude A((+)) is satisfied within 20% at threshold. The absence of a theoretical explanation for the ghosts and the lack of chiral symmetry in these previous studies led us to re-investigate the subject using the approach of the linear sigma-model and study the interplay of low-energy theorems for pi N scattering and ghost poles. For bare interaction vertices we find that ghosts are present in this model as well and that the A((+)) value is badly described, As a first approach to remove these complex poles, we dress the vertices with phenomenological form factors and a reasonable agreement with experiment is achieved, In order to fix the two cutoff parameters, we use the A((+)) value for the chiral limit (m(pi) --> 0) and the experimental value of the isoscalar scattering length, Finally, we test our model by calculating the phase shifts for the S waves and we find a good agreement at threshold. (C) 1997 Elsevier B.V. B.V.

EFFECT OF TREATMENT WITH GROWTH-REGULATORS AND SCARIFICATION ON THE TOLERANCE TO WATER-STRESS IN SEEDS OF ORYZA-SATIVA LCVIAC-165

The effect of treatment of seeds of Oryza sativa L. cv. IAC 165 with gibberellic acid, 6-benzyladenine and ethrel on the tolerance to the water stress were analysed. Gibberellic acid had no effect and 6-benzyladenine and ethrel promoted slight increase in the tolerance to water stress, specially in darkness. After scarification, those growth regulator presented no effect. Our results suggest that 6-benzyladenine and ethrel promoted water stress tolerance due to the decrease in the resistance of the seed coat to embryo expansion.

Seletividade e eficácia de herbicidas inibidores da enzima accase na cultura da mamona

This experiment aimed to evaluate the selectivity and efficacy of ACCase-inhibiting herbicides in castor bean crop, at Paraguacu Paulista, São Paulo, during the 2002/03 agricultural season. The experimental design used was randomized complete blocks, with eleven treatments and four replicates, constituted by the following herbicides and adjuvants: fluazifop-p-butyl 313 g ha(-1)) + Agral (TM) 0.2% v/v); sethoxydim 322 g ha(-1)) + Assist (TM) 0.5% v/v); haloxyfop-methyl 120 g ha(-1)) + Assist (TM) 0.5% v/v); clethodim+ fenoxaprop-p-ethyl 75 g ha(-1)) + Assist (TM) 0.5% v/v); quizalofop-pethyl 125 g ha(-1)) + Assist (TM) 0.5% v/v); clethodim 156 g ha(-1)) + Assist (TM) 0.5% v/v); propaquizafop 175 g ha(-1)) + Assist (TM) 0.5% v/v); tepraloxydim 400 g ha(-1)) + Dash (TM) 0.5% v/v); butroxydim 100 g ha(-1)) + Dash (TM) 0.5% v/v); isoxaflutole 60 g ha(-1)) and weed-free check. At the moment of application, castor bean plants presented 4 to 6 leaves and Cenchrus echinatus, 1 to 5 tillers. AL Guarany 2002 cultivar presented high selectivity to ACCase-inhibiting herbicides, without visible symptoms of phytotoxicity in 14 DAA days after application), except for tepraloxydim, whose symptoms persisted until 21 DAA, and isoxaflutole HPPD inhibiting), which showed injuries in older leaves and significant yield reduction. C. echinatus infestation was efficiently controlled by ACCase-inhibiting herbicides between 14 and 21 DAA (>= 95.0%).

Effect of drying method on the sorption isotherms and isosteric heat of persimmon pulp powder

Moisture equilibrium data of persimmon pulp powders with 50% maltodextrin (dry basis) obtained with different drying methods were determined at 20, 30, 40 and 50 degrees C. The spray-dryer gave a dry product with a higher adsorption capacity than the other methods. The vacuum- and freeze-dried products had the same adsorption capacity. The highest isosteric heat of sorption was observed for powders produced by spray-drying. The isokinetic temperature (T(B)) calculated for persimmon pulp powder obtained by vacuum-, spray- and freeze-drying were 541.4 K, 616.3 K, 513.2 K, respectively. The sorption process was spontaneous and enthalpy controlled.

Photopatternable di-ureasil-zirconium oxocluster organic-inorganic hybrids as cost effective integrated optical substrates

Organic-inorganic hybrids containing methacrylic acid (McOH, CH(2)= C(CH(3))COOH)) modified zirconium tetrapropoxide, Zr(OPr(n))(4), classed as di-ureasil-zirconium oxo-cluster hybrids, have been prepared and structurally characterized by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), Fourier transform infrared (FT-IR) and Raman (FT-Raman) spectroscopies, Si and C nuclear magnetic resonance (NMR), and atomic force microscopy (AFM). XRD and SAXS results have pointed out the presence of Si- and Zr-based nanobuilding blocks (NBBs) dispersed into the organic phase. Inter-NBBs correlation distances have been estimated for the pure di-ureasil and a model compound obtained. by hydrolysis/condensation of Zr(OPr(n))(4):McOH (molar ratio 1: 1): d(Si) approximate to 26 +/- 1 angstrom and d(Zr) approximate to 16 +/- 1 angstrom, respectively. In the case of the di-ureasil-zirconium oxo-cluster hybrids, these distances depend on the Zr relative molar percentage (rel. mol. Zr %) (d(Si) ranges from 18 to 25 angstrom and d(Zr) from 14 to 23 angstrom, as the rel. mol. Zr % increases from 5 to 75), suggesting that the Si- and Zr-based clusters are interconstrained. Complementary data from FT-IR, FT-Raman, (29)Si and (13)C NMR, and AFM support to a structural model where McOH-modified Zr-based NBBs (Zr-OMc) are present over the whole range of composition. At low Zr-OMc contents (rel. mol. Zr % <30) the clusters are well-dispersed within the di-ureasil host, whereas segregation occurs at the 0.1 mu m scale at high Zr-OMc concentration (rel. mol. Zr % = 50). No Zr-O-Si heterocondensation has been discerned. Monomode waveguides, diffractions gratings, and Fabry-Perot cavities have been written through the exposure of the hybrid monoliths to UV light. FT-Raman has shown that the chemical process that takes place under illumination is the polymerization of the methacrylate groups of the Zr-OMc NBBs. The guidance region in patterned channels is a Gaussian section located below the exposed surface with typical dimensions of 320 mu m wide and 88 mu m deep. The effective refractive index is 1.5162 (maximum index contrast on the order of 1 x 10(-4)) and the reflection coeficient of the Fabry-Perot cavity (formed by a grating patterned into a 0.278 cm channel) is 0.042 with a free spectral range value of 35.6 GHz.

Structural refinement and photoluminescence properties of irregular cube-like (Ca-1_Cu-x(x))TiO3 microcrystals synthesized by the microwave-hydrothermal method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pectin lyase from Aspergillus giganteus: Comparative study of productivity of submerged fermentation on citrus pectin and orange waste

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Similar anxiolytic-like effects following intra-amygdala infusions of benzodiazepine receptor agonist and antagonist: Evidence for the release of an endogenous benzodiazepine inverse agonist in mice exposed to elevated plus-maze test

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relationship between dog culling and incidence of human visceral leishmaniasis in an endemic area

Domestic dogs are the main reservoirs of visceral leishmaniasis (VL) in urban areas; one of the control measures adopted in Brazil is the elimination of this reservoir. In order to test the relationship between the euthanasia rate of the canine reservoir and the incidence of the disease in humans, data on dog culling from the Centre for Zoonosis Control of Aracatuba, São Paulo, Brazil, during the period from 1999 to 2008 and visceral leishmaniasis human cases registered in the same period were analyzed. Reduction of human VL incidence was statistically correlated to dog euthanasia rate (P=0.0211; r(2)=0.616) when it was analyzed for the period of two years after application of this measure. Other factors that may influence this relationship are considered. (C) 2010 Elsevier B.V. All rights reserved.

Leishmania chagasi infection in cats with dermatologic lesions from an endemic area of visceral leishmaniosis in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of Ca, Mg, and Zn in biodiesel microemulsions by FAAS using discrete nebulization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and Photoluminescence Behavior of the Eu3+ Ions as a Nanocoating over a Silica Stober Matrix

In this work, a SiO2 spherical were prepared by the Stober Method and then recovered with a single layer of Eu2O3 oxide (SiO2@Eu2O3) obtained by the Polymeric Precursor Method. The SiO2@Eu2O3 powder was heated treated at 100, 300, 400, 500 and 800 A degrees C. The samples were characterized by the Scanning Electonic Microscopy (SEM), Thermal Analysis (TGA/DTA), and the luminescent properties of the SiO2@Eu2O3 powders were studied by their emission and excitation spectra as well as by the lifetime measurements of the Eu3+ D-5(0) -> aEuro parts per thousand F-7(2) transition. The SEM analysis shows that the silica prepared by the Stober Method is spherical with a particle size of 460 nm. The emission spectra of the SiO2@Eu2O3 powders presented the Eu3+ characteristics bands related to the D-5(0) -> aEuro parts per thousand F-7(J) (J = 0, 1, 2, 3, 4) transitions at 577, 591, 616, 649 and 695 nm, respectively. The band related to the D-5(0) -> aEuro parts per thousand F-7(2) transition is the most intense in the spectra, and its intensity decreases with the temperature enhancement. The decay curves of the SiO2@Eu2O3 samples presented monoexponential features, and the obtained lifetime values were higher than the Eu2O3 oxide. It was possible to conclude that the D-5(0) -> aEuro parts per thousand F-7(2) hypersensitive transition is strongly dependent on the Eu3+ surrounding.

Analysis of bone microarchitecture related to anthropometry in climateric women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)