The use of essential oils to protect rice from storage fungi

Rice (Oryza sativa) is the main food of half of the population of our planet. The growth of fungi closely associated to the eventual occurrence of mycotoxins can be responsible for serious economic losses and public health risks. Knowledge about the origin of the growth of toxigenic fungi is a prerequisite to the establishment of mycotoxin control programs. Socio-economical and environmental factors led to an extreme reduction of rice availability, while the estimated rice production losses increased in all continents what increases the importance to develop new harmless strategies for the control of fungi affecting stored rice. Natural products from plant origin were screened for the control of main pernicious fungi.In this work we have collected rice samples from different origins (national and imported) and these samples were analysed for fungal infection. Several fungi taxa were isolated: Absidia, Alternaria, Aspergillus, Bipolaris, Botrytis, Chaetomium, Curvularia, Cunninghamela, Epicoccum, Fusarium, Geotrichum, Helicoma, Nigrospora, Penicillium, Pyricularia, Rhizopus, Scytalidium, Stemphylium, Sordaria, Trichoconiella, Trichoderma, Trichothecium and Ulocladium. Some of the fungi isolated are potentially mycotoxigenic. We also studied a way to control the growth of some of these fungi using plant extracts and essential oils from Syzyginum aromaticum and Laurus nobilis. Promising results were obtained.Keywords: Rice, Cereals, Fungi, Bio-pesticides, Plant extracts

Evaluation of the phase discretization effect in transmitarrays formed by sub-wavelength patches

Most of the transmitarray phase shifting cell designs assume a periodic repetition of the same cell to account for the coupling effects of the neighboring cells. However the behavior in terms of magnitude and phase of the transmission coefficient calculated in this way may change when the neighboring cells have different phase, as normally happens in transmitarrays due to phase discretization. This paper characterizes this effect using a family of sub-wavelength patch cells covering the entire 360º phase shift interval, all with transmission coefficient better than -0.2 dB in the periodic structure. A stepped-phase structure is analysed considering different phase step values from 5º up to 90º. It is shown that the magnitude of the cells transmission factor changes considerably at the transition between different elements, with the unit cells with higher phase shift showing increased transmission while the lower phase shift cells in the transition tend to block the transmission more.info:eu-repo/semantics/acceptedVersio

Mutant Ataxin-2 expression in aged animals aggravates neuropathological features associated with Spinocerebellar Ataxia type 2

Spinocerebellar ataxia type 2 (SCA2) is a rare autosomal, dominantly inherited disease, in which the affected individuals have a disease onset around their third life decade. The molecular mechanisms underlying SCA2 are not yet completely understood, for which we hypothesize that aging plays a role in SCA2 molecular pathogenesis. In this study, we performed a striatal injection of mutant ataxin-2 mediated by lentiviral vectors, in young and aged animals. Twelve weeks post-injection, we analyzed the striatum for SCA2 neuropathological features and specific aging hallmarks. Our results show that aged animals had a higher number of mutant ataxin-2 aggregates and more neuronal marker loss, compared to young animals. Apoptosis markers, cleaved caspase-3, and cresyl violet staining also indicated increased neuronal death in the aged animal group. Additionally, mRNA levels of microtubule-associated protein 1 light-chain 3B (LC3) and sequestosome-1 (SQSTM1/p62) were altered in the aged animal group, suggesting autophagic pathway dysfunction. This work provides evidence that aged animals injected with expanded ataxin-2 had aggravated SCA2 disease phenotype, suggesting that aging plays an important role in SCA2 disease onset and disease progression.info:eu-repo/semantics/publishedVersio

Prototype of a compact mechanically steered Ka-band antenna for satellite on-the-move

We present a functional prototype of a SOTM user terminal antenna based on a planar offset Fresnel lens that implements a new mechanical steering concept previously proposed by the authors. The beam scanning is achieved by inplane translation of the feed (for zenith scanning) and axial rotation of the antenna (for azimuth scanning). The feed is as assembly of a circular polarization patch and a small planar lens. The goal of the small lens is two-fold : to adjust the primary feed directivity for a proper illumination of the main lens and to shift backwards the phase center of the patch, allowing reducing the antenna height. In the developed prototype the measured gain is 27 dBi at 30 GHz with a scan loss of 3 dB for an elevation scanning range between 18° and 53° for full azimuth. The antenna provides good circular polarization, with a cross polarization level below -14 dB. The side lobe level is below -10 dB for all beams positions. The antenna weight is less than 500 grams.info:eu-repo/semantics/acceptedVersio

On the Hydrogen Atom via Wigner-Heisenberg Algebra

We extend the usual Kustaanheimo-Stiefel $4D\to 3D$ mapping to study and discuss a constrained super-Wigner oscillator in four dimensions. We show that the physical hydrogen atom is the system that emerges in the bosonic sector of the mapped super 3D system.Comment: 14 pages, no figure. This work was initiated in collaboration with Jambunatha Jayaraman (In memory), whose advises and encouragement were fundamental. http://www.cbpf.b

Electrochemical methods in pesticides control

The state of the art of voltammetric and amperometric methods used in the study and determination of pesticides in crops, food, phytopharmaceutical products, and environmental samples is reviewed. The main structural groups of pesticides, i.e., triazines, organophosphates, organochlorides, nitrocompounds, carbamates, thiocarbamates, sulfonylureas, and bipyridinium compounds are considered with some degradation products. The advantages, drawbacks, and trends in the development of voltammetric and amperometric methods for study and determination of pesticides in these samples are discussed

Experimental evaluation of a high gain dual-band beam steerable transmit-array

This paper presents the design and measurement of a novel transmit-array (TA) that is able to combine wide beam steering and high gain for two distinct frequency bands. The TA is designed for a mobile ground platform to operate at satellite communications in the Ka-bands: Rx (19.7-20.2 GHz) and Tx (29.5-30.0 GHz). A 28 dBi gain is obtained for 30 GHz and 24 dBi for 20 GHz. The zenith beam steering results from a linear displacement of the aperture in front of a stationary feed. A scanning range of 50º was obtained with 2dB scan loss. Overall, the dual-band TA performs as well as if two independent single band apertures were designedinfo:eu-repo/semantics/acceptedVersio

High-redshift objects and the generalized Chaplygin gas

Motivated by recent developments in particle physics and cosmology, there has been growing interest in an unified description of dark matter and dark energy scenarios. In this paper we explore observational constraints from age estimates of high-$z$ objects on cosmological models dominated by an exotic fluid with equation of state $p = -A/\rho^{\alpha}$ (the so-called generalized Chaplygin gas) which has the interesting feature of interpolating between non-relativistic matter and negative-pressure dark energy regimes. As a general result we find that, if the age estimates of these objects are correct, they impose very restrictive limits on some of these scenarios.Comment: 5 pages, 3 figures, to appear in Phys. Rev.

Wide-angle mechanical scanning Transmit-arrays for satellite Ka-band user terminals

The antenna design for broadband satellite communications is particularly challenging, new cost-effective solutions are still needed. An overview of recent contributions from the authors on planar transmit-arrays (TAs) for satellite Kaband user terminals is presented. We tackle several design problems: how to improve the scanning coverage using low cost mechanical beam steering, how to choose the type of unit cells that compose the TA, how to devise a single aperture with high gain that operates simultaneous at two widely separate frequency bands. Different prototypes are used to conduct these studies. All these TAs provide wide beam zenith scanning, [-50º,50º] with less that 3dB of scan loss, good circular polarization performance and low beam distortions. The prototypes have the same aperture size, 195 × 145 mm2, that provide gains up to 29 dBi for 30 GHz.info:eu-repo/semantics/acceptedVersio

Avaliação da incidência de vírus em acessos de pimenta em campo.

Resumo 854-