Relation between incidence of Fusarium graminearum in seeds, emergence and occurrence of giberela in wheat seedlings

Com o objetivo de verificar o comportamento de 30 genótipos de trigo em relação à emergência e à incidência de giberela em plântulas provenientes de sementes portadoras de Fusarium graminearum, foram instalados experimentos de laboratório e casa-de-vegetação. Em laboratório, as sementes utilizadas para os experimentos de emergência e incidência de giberela foram analisadas para sanidade pelo método do papel de filtro com congelamento. Em casa-de-vegetação, as sementes foram distribuídas em caixas de plástico, contendo areia tratada com brometo de metila. O delineamento utilizado foi o de blocos casualizados, constituído de 30 tratamentos com quatro repetições de 50 sementes, perfazendo um total de 200 sementes/tratamento. As avaliações da emergência de plântulas e da incidência de giberela foram feitas aos sete, 14 e 21 dias após a semeadura (DAS), contando-se o número de plântulas emergidas e retirando-se as plântulas sintomáticas, as quais foram submetidas a câmara úmida, por 24 horas, em laboratório. Não houve diferença significativa da incidência do patógeno na emergência das plântulas. Não foi constatada correlação entre a incidência de giberela nas plântulas e o nível de resistência dos genótipos, bem como entre incidência de giberela nas plântulas e a incidência do patógeno nas sementes.In order to verify the behavior of 30 genotypes of wheat in relation to the emergence and incidence of giberela in wheat seedlings from seeds contaminated with F. graminearum, experiments were carried out under laboratory and greenhouse conditions. In the laboratory, seeds were analyzed for health using freezer blotter test. In the greenhouse, seeds were sowed in plastic boxes filled with sand treated with methyl bromide. Statistical design was randomized blocks with 30 treatments, four replications of 50 seeds (200 seeds/treatment). Emergence of seedlings and giberela incidence were evaluated at seven, 14 and 21 days after sowing. Symptomatic seedlings were removed and submitted to humid chambers for 24 hours under laboratory conditions. There was no significant difference in the incidence of the pathogen in the emergence of seedlings. There was no correlation between the incidence of F. graminearum in the genotypes and incidence of giberela in seedlings, nor between the incidence of giberela in seedlings and the incidence of the pathogen in the seeds

On the trace identity in a model with broken symmetry

Considering the simple chiral fermion meson model when the chiral symmetry is explicitly broken, we show the validity of a trace identity -- to all orders of perturbation theory -- playing the role of a Callan-Symanzik equation and which allows us to identify directly the breaking of dilatations with the trace of the energy-momentum tensor. More precisely, by coupling the quantum field theory considered to a classical curved space background, represented by the non-propagating external vielbein field, we can express the conservation of the energy-momentum tensor through the Ward identity which characterizes the invariance of the theory under the diffeomorphisms. Our ``Callan-Symanzik equation'' then is the anomalous Ward identity for the trace of the energy-momentum tensor, the so-called ``trace identity''.Comment: 11 pages, Revtex file, final version to appear in Phys.Rev.

Capturing complexity: field-testing the use of ‘structure from motion’ derived virtual models to replicate standard measures of reef physical structure

Reef structural complexity provides important refuge habitat for a range of marine organisms, and is a useful indicator of the health and resilience of reefs as a whole. Marine scientists have recently begun to use ‘Structure from Motion’ (SfM) photogrammetry in order to accurately and repeatably capture the 3D structure of physical objects underwater, including reefs. There has however been limited research on the comparability of this new method with existing analogue methods already used widely for measuring and monitoring 3D structure, such as ‘tape and chain rugosity index (RI)’ and graded visual assessments. Our findings show that analogue and SfM RI can be reliably converted over a standard 10-m reef section (SfM RI = 1.348 × chain RI—0.359, r2 = 0.82; and Chain RI = 0.606 × SfM RI + 0.465) for RI values up to 2.0; however, SfM RI values above this number become increasingly divergent from traditional tape and chain measurements. Additionally, we found SfM RI correlates well with visual assessment grades of coral reefs over a 10 × 10 m area (SfM RI = 0.1461 × visual grade + 1.117; r2 = 0.83). The SfM method is shown to be affordable and non-destructive whilst also allowing the data collected to be archival, less biased by the observer, and broader in its scope of applications than standard methods. This work allows researchers to easily transition from analogue to digital structural assessment techniques, facilitating continued long-term monitoring, whilst also improving the quality and additional research value of the data collected

Critical flux pinning and enhanced upper-critical-field in magnesium diboride films

We have conducted pulsed transport measurements on c-axis oriented magnesium diboride films over the entire relevant ranges of magnetic field 0 \alt H \alt H_{c2} (where \hcu is the upper critical field) and current density 0 \alt j \alt j_{d} (where $j_{d}$ is the depairing current density). The intrinsic disorder of the films combined with the large coherence length and three-dimensionality, compared to cuprate superconductors, results in a six-fold enhancement of $H_{c2}$ and raises the depinning current density $j_{c}$ to within an order of magnitude of $j_{d}$. The current-voltage response is highly non-linear at all fields, resulting from a combination of depinning and pair-breaking, and has no trace of an Ohmic free-flux-flow regime. Keywords: pair, breaking, depairing, superconductor, superconductivity, flux, fluxon, vortex, mgb

ChemT, a software for building template-based 3D chemical libraries.

ln the modem drug discovery process vast quantities of compounds are generated and there is a need for bioinformatic tools to efficiently create, manage and examine huge chemical compound libraries. Severa! software tools for drawing and generating chemical compounds structures are available, but they usually lack options for automatic generation of custom-made focused chemicallibraries. We have implemented ChemT (Chemical Templates), a free software too! that automates the process of preparing template-based three-dimensional chemical libraries. ChemT accepts severa! file fonnats and is able to select compounds by imposing limits according to different physicochemical properties or by applying a Lipinski Rule of Fives filter. The compounds on the library are subject to force field minimization and the resulting threedimensional sh·uctures can be recorded on severa! file fonnats more frequently used in Virtual Screening projects. ChemT was developed using C-sharp language and compiled for Windows using SharpDevelop3.5. For file fonnat conversions, properties calculation and compound energy minimization ChemT uses the OpenBabel OBDotNet library. For compound energy minimization ChemT uses the Universal Force Field available with OpenBabel. As supporters of free open-source software ChemT is freely available on his website (www.esa.ipb.pt/~ruiabreu/chemt). ChemT is a fast easy-to-use software that automatically generates three-dimensional chemical libraries by inputting a chemical template and functional groups of interest. A fairly self-explanatory Graphical User Interface is provided and severa! tools for compound filtering are included. ChemT can be a valuable too! for chemists interested in using virtual screening tools in arder to prioritize compounds for further chemical synthesis

Atomic layering at the liquid silicon surface: a first- principles simulation

We simulate the liquid silicon surface with first-principles molecular dynamics in a slab geometry. We find that the atom-density profile presents a pronounced layering, similar to those observed in low-temperature liquid metals like Ga and Hg. The depth-dependent pair correlation function shows that the effect originates from directional bonding of Si atoms at the surface, and propagates into the bulk. The layering has no major effects in the electronic and dynamical properties of the system, that are very similar to those of bulk liquid Si. To our knowledge, this is the first study of a liquid surface by first-principles molecular dynamics.Comment: 4 pages, 4 figures, submitted to PR

Mesoscopic effects in tunneling between parallel quantum wires

We consider a phase-coherent system of two parallel quantum wires that are coupled via a tunneling barrier of finite length. The usual perturbative treatment of tunneling fails in this case, even in the diffusive limit, once the length L of the coupling region exceeds a characteristic length scale L_t set by tunneling. Exact solution of the scattering problem posed by the extended tunneling barrier allows us to compute tunneling conductances as a function of applied voltage and magnetic field. We take into account charging effects in the quantum wires due to applied voltages and find that these are important for 1D-to-1D tunneling transport.Comment: 8 pages, 7 figures, improved Figs., added Refs. and appendix, to appear in Phys. Rev.

Variability of satellite derived phenological parameters across maize producing areas of South Africa

Changes in phenology can be used as a proxy to elucidate the short and long term trends in climate change and variability. Such phenological changes are driven by weather and climate as well as environmental and ecological factors. Climate change affects plant phenology largely during the vegetative and reproductive stages. The focus of this study was to investigate the changes in phenological parameters of maize as well as to assess their causal factors across the selected maize-producing Provinces (viz: North West, Free State, Mpumalanga and KwaZulu-Natal) of South Africa. For this purpose, five phenological parameters i.e., the length of season (LOS), start of season (SOS), end of season (EOS), position of peak value (POP), and position of trough value (POT) derived from the MODIS NDVI data (MOD13Q1) were analysed. In addition, climatic variables (Potential Evapotranspiration (PET), Precipitation (PRE), Maximum (TMX) and Minimum (TMN) Temperatures spanning from 2000 to 2015 were also analysed. Based on the results, the maize-producing Provinces considered exhibit a decreasing trend in NDVI values. The results further show that Mpumalanga and Free State Provinces have SOS and EOS in December and April respectively. In terms of the LOS, KwaZulu-Natal Province had the highest days (194), followed by Mpumalanga with 177 days, while NorthWest and Free State Provinces had 149 and 148 days, respectively. Our results further demonstrate that the influences of climate variables on phenological parameters exhibit a strong space-time and common covariate dependence. For instance, TMN dominated in North West and Free State, PET and TMX are the main dominant factors in KwaZulu-Natal Province whereas PRE highly dominated in Mpumalanga. Furthermore, the result of the Partial Least Square Path Modeling (PLS-PM) analysis indicates that climatic variables predict about 46% of the variability of phenology indicators and about 63% of the variability of yield indicators for the entire study area. The goodness of fit index indicates that the model has a prediction power of 75% over the entire study area. This study contributes towards enhancing the knowledge of the dynamics in the phenological parameters and the results can assist farmers to make the necessary adjustment in order to have an optimal production and thereby enhance food security for both human and livestock.The Department of Science and Technology (DST) and The National Research Foundation (NRF).http://www.mdpi.com/journal/sustainabilityam2018Animal and Wildlife SciencesGeography, Geoinformatics and MeteorologyPlant Production and Soil Scienc