Initial in vitro evaluations of antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria

Aims: The aim of the study was to evaluate the in vitro antibacterial effects of glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas juglandis. Methods and Results: Using a disc diffusion assay, seven different doses of 10 GHP were tested against each bacteria. The results showed that the isothiocyanates were potent antibacterials, whilst the other GHP were much less efficient. Moreover, the antibacterial effects were dose-dependent, increasing with the dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest inhibitory effects. The overall results show a great potential for using the isothiocyanates as an alternative tool to control undesired bacterial growth in plants. Conclusions: Glucosinolate hydrolysis products and more specifically the isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate Mix and sulforaphane, were effective phytochemicals against the in vitro growth of the phytopathogenic bacteria. The antibacterial activity exhibited by these phytochemicals reinforces their potential as alternatives to the traditional chemical control of phytopathogenic bacteria. Significance and Impact of the Study: This current in vitro study is the first providing comparative data on GHP as potential control agents for plant pathogenic bacteria. However, more studies are needed to determine their possible allelopathic impacts e.g. inhibition of plant growth and negative effects on beneficial soil bacteria and fungi (mycorrhizae

Necessidades de irrigação suplementar em soja nas condições edafoclimáticas do Planalto Médio e Missões, RS.

Este trabalho foi conduzido com a finalidade de estimar as necessidades estocásticas de irrigação suplementar por aspersão na cultura da soja (Glycine max L. Merrill), nas regiões agroecológicas do Estado do Rio Grande do Sul, denominadas de Planalto Médio e Missões. As necessidades foram simuladas em relação à combinação entre locais, épocas de semeadura, níveis de manejo da irrigação e entre níveis de ocorrência . As necessidades de irrigação suplementar foram máximas na semeadura de 15 de outubro, e os menores valores foram encontrados na semeadura de 15 de dezembro; as necessidades de irrigação suplementar foram maiores nas condições agroecológicas das Missões quando comparadas com as do Planalto Médio; as lâminas de irrigação suplementar estimadas aumentaram à medida que o nível de risco diminuiu

Quinstant Dark Energy Predictions for Structure Formation

We explore the predictions of a class of dark energy models, quinstant dark energy, concerning the structure formation in the Universe, both in the linear and non-linear regimes. Quinstant dark energy is considered to be formed by quintessence and a negative cosmological constant. We conclude that these models give good predictions for structure formation in the linear regime, but fail to do so in the non-linear one, for redshifts larger than one.Comment: 9 pages, 14 figures, "Accepted for publication in Astrophysics & Space Science

The excitation spectrum of mesoscopic proximity structures

We investigate one aspect of the proximity effect, viz., the local density of states of a superconductor-normal metal sandwich. In contrast to earlier work, we allow for the presence of an arbitrary concentration of impurities in the structure. The superconductor induces a gap in the normal metal spectrum that is proportional to the inverse of the elastic mean free path l_N for rather clean systems. For a mean free path much shorter than the thickness of the normal metal, we find a gap size proportional to l_N that approaches the behavior predicted by the Usadel equation (diffusive limit). We also discuss the influence of interface and surface roughness, the consequences of a non-ideal transmittivity of the interface, and the dependence of our results on the choice of the model of impurity scattering.Comment: 7 pages, 8 figures (included), submitted to PR

Gravitational Collapse of Phantom Fluid in (2+1)-Dimensions

This investigation is devoted to the solutions of Einstein's field equations for a circularly symmetric anisotropic fluid, with kinematic self-similarity of the first kind, in $(2+1)$-dimensional spacetimes. In the case where the radial pressure vanishes, we show that there exists a solution of the equations that represents the gravitational collapse of an anisotropic fluid, and this collapse will eventually form a black hole, even when it is constituted by the phantom energy.Comment: 10 page

Cosmological Scaling Solutions with Tachyon:Modified Gravity Model

Modifying the Einstein's gravity at large distance scales is one of the interesting proposals to explain the late time acceleration of the universe. In this paper, we analyse scaling solutions in modified gravity models where the universe is sourced by a background matter fluid together with a tachyon type scalar field. We describe a general prescription to calculate the scaling potential in such models. Later on, we consider specific examples of modifications and apply our method to calculate the scaling potential and the scale factor. Our method can be applied to any modified gravity model, in presence of a tachyon field.Comment: 6 pages, latex style, modified version, two new figures included, new refernces added, Accepted for publication in Physics Letters

Excess adiposity and low physical fitness hamper Supine-to-Stand test performance among sedentary adolescents

Objective: The aim of this study was to analyze the relationship between body adiposity and physical fitness with performance in the Supine-to-Stand test (STS-test) in sedentary adolescents. Methods: Sixty-two adolescents, of both sexes, between 10 and 16 years old, participated in the study. Body mass (BM), height, waist circumference (WC), fat mass (FM), fat-free mass (FFM), right and left handgrip strength (HGS-right, HGS-left), abdominal resistance (ABDO), flexibility (FLEX), and cardiorespiratory fitness (VO2peak) were measured. Body mass index (BMI), z-score BMI (BMI-z), tri-ponderal mass index (TMI) and waist-to-height ratio (WHtR) were calculated. The STS-test was applied to evaluate the STS-MC by the movement patterns in the execution of the test. The STS-time in seconds (s) was categorized into terciles: fast (FG  2.6 s). One-way ANOVA, Chi-square, Spearman's correlation coefficient as well as non-parametric tests were used, with significance p ≤ 0.05. Results: The SG presented higher BMI, BMI-z, TMI, WHtR, FM, %FM, as well as lower averages for %FFM, HGS-right, HGS-left, FLEX, ABDO, VO2peak, VO2peak relative to BM (VO2peakBM) in relation to GF. The BMI, BMI-z, TMI, WC, WHtR and FM showed moderate and direct correlations with STS-time and inverse with STS-MC (p < 0.01). HGS-right, HGS-left, ABDO, and VO2peakBM showed moderate and an inverse correlation with STS-time (p < 0.05). The VO2peakBM was moderate and with direct correlations to STS-MC (p < 0.01). Conclusion: It is concluded that excess fat and low physical fitness hamper STS-test performance. Therefore, the STS-test can be used for screening students to assess MC

Multiple Inflation, Cosmic String Networks and the String Landscape

Motivated by the string landscape we examine scenarios for which inflation is a two-step process, with a comparatively short inflationary epoch near the string scale and a longer period at a much lower energy (like the TeV scale). We quantify the number of $e$-foldings of inflation which are required to yield successful inflation within this picture. The constraints are very sensitive to the equation of state during the epoch between the two inflationary periods, as the extra-horizon modes can come back inside the horizon and become reprocessed. We find that the number of $e$-foldings during the first inflationary epoch can be as small as 12, but only if the inter-inflationary period is dominated by a network of cosmic strings (such as might be produced if the initial inflationary period is due to the brane-antibrane mechanism). In this case a further 20 $e$-foldings of inflation would be required at lower energies to solve the late universe's flatness and horizon problems.Comment: 27 pages, 6 figures; v2: refences adde

Magnetocaloric Effect In The Rni5 (r = Pr, Nd, Gd, Tb, Dy, Ho, Er) Series

In this paper, the magnetocaloric effect in the hexagonal intermetallic compounds belonging to the RNi5 series was calculated using a Hamiltonian including the crystalline electrical field, exchange interaction, and the Zeeman effect. Experimental work was performed and the two thermodynamics quantities, namely, isothermal entropy change and adiabatic temperature change were obtained for polycrystalline samples using heat capacity measurements, and compared to the theoretical predictions.70131344281-134428-6Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494Gschneidner Jr., K.A., Pecharsky, V.K., (1997) Rare Earths: Science, Technology and Application III, , edited by R. C. Bautista, C. O. Bounds, T. W. Ellis, and B. T. Kilbourn (The Minerals, Metals and Materials Society, Warendale, PATegus, O., Bruck, E., Buschow, K.H.J., De Boer, F.R., (2002) Nature (London), 415, p. 150Wada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 20(2001) Appl. Phys. Lett., 79, p. 3302Wada, H., Morikawa, T., Taniguchi, K., Shibata, T., Yamada, Y., Akishige, Y., (2003) Physica B, 328, p. 114Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78Von Ranke, P.J., De Campos, A., Caron, L., Coelho, A.A., Gama, S., De Oliveira, N.A., unpublishedVon Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) Phys. Lett. A, 320, p. 302Von Ranke, P.J., Lima, A.L., Nóbrega, E.P., Da Silva, X., Guimarães, A.P., Oliveira, I.S., (2001) Phys. Rev. B, 63, p. 024422Von Ranke, P.J., Pecharsky, V.K., Gschneidner, K.A., Korte, B.J., (1998) Phys. Rev. B, 58, p. 14436Buschow, K.H.J., Van Der Goot, A.S., (1971) Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem., 27, p. 1085Stevens, K.W.H., (1952) Proc. Phys. Soc., London, Sect. A, 65, p. 209Radwanski, R.J., Kim-Ngan, N.H., Kayzel, F.E., Franse, J.J.M., Gignoux, D., Schmitt, D., Zhang, F.Y., (1992) J. Phys.: Condens. Matter, 4, p. 8853Tishin, A.M., Magnetocaloric effect in the vicinity of phase transitions (1999) Handbook of Magnetic Materials, 12, pp. 395-524. , edited by K. H. J. Buschow (North-Holland Elsevier, Amsterdam, the Netherlands), Chap. 4Marzouk, N., Graig, R.S., Wallace, W.E., (1973) J. Phys. Chem. Solids, 34, p. 15Barthem, V.M.T.S., Gignoux, D., Schmitt, D., (1989) J. Magn. Magn. Mater., 78, p. 56Zhang, F.Y., Gignoux, D., Schmitt, D., Franse, J.J.M., Kayzel, F.E., Kim-Ngan, N.H., Radwanski, R.J., (1994) J. Magn. Magn. Mater., 130, p. 108Morellon, L., Algarabel, P.A., Ibarra, M.R., Del Moral, A., Gignoux, D., Schmitt, D., (1996) J. Magn. Magn. Mater., 153, p. 17Barthem, V.M.T.S., Gignoux, D., Nait-Saada, A., Schmitt, D., Takeuchi, A.Y., (1989) J. Magn. Magn. Mater., 80, p. 142Gignoux, D., Givord, D., Del Moral, A., (1976) Solid State Commun., 19, p. 891Andreeff, A., Valter, V., Grissmann, H., Kaun, L.P., Lipold, B., Mats, V., Franzkhaim, T., (1978) JINR Rapid Commun., 1978, pp. 14-11324Marzouk, N., Graig, R.S., Wallace, W.E., (1973) J. Phys. Chem. Solids, 34, p. 1