Avaliação da atividade inseticida de óleos essenciais de plantas da flora nordestina contra a mosca-branca (Bemisia argentifolii).

E conhecido que muitas plantas encerram micromoleculas oriundas do metabolismo secundario, tais como alcaloides, flavonoides, triterpenos, limnnoides, dentre outras, as quais apresentam funcao de protecao contra fitopatogenos e insetos fitofagos. Dos varios exemplos, podemos citar os glicoalcaloides em Solanaceace, os limonoides em Rutaceae, Meliaceae e Simarubaceae. Algumas dessas substancias sao conhecidas por suas propriedade inseticidas, dentre as quais podemos citar: rotenoides obtidos das especies de Lonchocarpus; nicotina de Nicotiana tabacum; precocenos de Ageratrum conyzoides e piretrinas de Crysanthemum cineraefolium (Craveiro e Machado, 1986).bitstream/CNPAT-2010/5858/1/Pa-080.pd

Elliptic Flow and Dissipation in Heavy-Ion Collisions at E_{lab} = (1--160)A GeV

Elliptic flow in heavy-ion collisions at incident energies $E_{lab}\simeq$ (1--160)A GeV is analyzed within the model of 3-fluid dynamics (3FD). We show that a simple correction factor, taking into account dissipative affects, allows us to adjust the 3FD results to experimental data. This single-parameter fit results in a good reproduction of the elliptic flow as a function of the incident energy, centrality of the collision and rapidity. The experimental scaling of pion eccentricity-scaled elliptic flow versus charged-hadron-multiplicity density per unit transverse area turns out to be also reasonably described. Proceeding from values of the Knudsen number, deduced from this fit, we estimate the upper limit the shear viscosity-to-entropy ratio as $\eta/s \sim 1-2$ at the SPS incident energies. This value is of the order of minimal $\eta/s$ observed in water and liquid nitrogen.Comment: 10 pages, 7 figures, version accepted by Phys. Rev.

High Resolution Crystal Structures of the Wild Type and Cys-55 right-arrow Ser and Cys-59 right-arrow Ser Variants of the Thioredoxin-like [2Fe-2S] Ferredoxin from Aquifex aeolicus

The [2Fe-2S] ferredoxin (Fd4) from Aquifex aeolicus adopts a thioredoxin-like polypeptide fold that is distinct from other [2Fe-2S] ferredoxins. Crystal structures of the Cys-55 right-arrow Ser (C55S) and Cys-59 right-arrow Ser (C59S) variants of this protein have been determined to 1.25 Å and 1.05 Å resolution, respectively, whereas the resolution of the wild type (WT) has been extended to 1.5 Å. The improved WT structure provides a detailed description of the [2Fe-2S] cluster, including two features that have not been noted previously in any [2Fe-2S] cluster-containing protein, namely, pronounced distortions in the cysteine coordination to the cluster and a Calpha -H-Sgamma hydrogen bond between cluster ligands Cys-55 and Cys-9. These features may contribute to the unusual electronic and magnetic properties of the [2Fe-2S] clusters in WT and variants of this ferredoxin. The structures of the two variants of Fd4, in which single cysteine ligands to the [2Fe-2S] cluster are replaced by serine, establish the metric details of serine-ligated Fe-S active sites with unprecedented accuracy. Both the cluster and its surrounding protein matrix change in subtle ways to accommodate this ligand substitution, particularly in terms of distortions of the Fe2S2 inorganic core from planarity and displacements of the polypeptide chain. These high resolution structures illustrate how the interactions between polypeptide chains and Fe-S active sites reflect combinations of flexibility and rigidity on the part of both partners; these themes are also evident in more complex systems, as exemplified by changes associated with serine ligation of the nitrogenase P cluster

Sistema “mixto” de producción de semilla de papa entre el INIAP y el CONPAPA.

La papa representa el 7.4% del Producto Interno Bruto Agropecuario (PIBA) del Ecuador. Se estima que 30.000 t es el volumen anual de papa procesada. Utiliza mano de obra en forma intensiva. El 10,5% de los trabajadores agropecuarios están involucrados en este cultivo. En el período 2002 a 2006, se reporta una producción de 409.733 t de papa al año, con una superficie de cultivo de 43.300 ha y un rendimiento de 9,5 t/ha. Menos del 2% de la superficie de papa se siembra con semilla del sistema formal. El resto se lo hace con material proveniente del sistema informal, el cual presenta deficiencias de calidad, cantidad, oportunidad. El CONPAPA es una organización que busca el posicionamiento de productores de pequeña y mediana escala en segmentos de mercado de alto valor agregado, lo que constituye un reto para este nivel de agricultores. En este esquema, el principal limitante resultó ser la falta de semilla de calidad, cantidad, oportunidad y estado fisiológico en que necesitan los socios, lo que obligó a la construcción de un sistema “mixto” de semilla. Dicho sistema funciona así: INIAP genera una nueva variedad y determina los usos más adecuados para la misma, promueve su uso en nichos específicos de manera que se induzca a la utilización de la misma. Una vez que se ha generado demanda se limpia de virus y patógenos, se produce semilla limpia y se entrega al CONPAPA de la provincia de Tungurahua, el cual se encarga de multiplicar semilla por dos o tres generaciones con sus semilleristas. Posteriormente realiza el Control Interno de Calidad (CIC) y entrega a sus socios para que produzcan papa comercial. Los actores del sistema son: el INIAP como proveedor de nuevas variedades, tecnología, semilla inicial limpia; el CONPAPA de la provincia de Tungurahua quien compra la semilla y distribuye para sus semilleristas y luego adquiere el material que ha sido multiplicado; los semilleristas quienes la multiplican a partir del material limpio; y finalmente los agricultores productores de papa comercial. El CIC se realiza entre el técnico de la organización, el promotor y el semillerista. Para la comercialización se utiliza un esquema de contratación, mayoritariamente verbal. Los precios se basan en los costos de producción más una ganancia. Los resultados relevantes son: el CONPAPA produce y comercializa entre 150 a 200 t por año y la organización es reconocida y sostenible. Las fortalezas son: semilleristas capacitados y experimentados, posicionamiento en el mercado, capital propio, infraestructura para procesamiento y almacenamiento y protocolo de CIC. Las oportunidades son: demanda de semilla por parte de organizaciones de productores, ONGs, OGs. Las debilidades son: falta consolidación de la organización, éxodo de productores. Finalmente, las amenazas son: inestabilidad del precio de la papa y de la semilla, disminución del consum

The XMM spectral catalog of SDSS optically selected Seyfert 2 galaxies

We present an X-ray spectroscopic study of optically selected (SDSS) Seyfert 2 (Sy2) galaxies. The goal is to study the obscuration of Sy2 galaxies beyond the local universe, using good quality X-ray spectra in combination with high S/N optical spectra for their robust classification. We analyzed all available XMM-Newton archival observations of narrow emission line galaxies that meet the above criteria in the redshift range 0.05<z<0.35. We initially selected narrow line AGN using the SDSS optical spectra and the BPT classification diagram. We further modeled and removed the stellar continuum, and we analyzed the residual emission line spectrum to exclude any possible intermediate-type Seyferts. Our final catalog comprises 31 Sy2 galaxies with median redshift z~0.1. X-ray spectroscopy is performed using the available X-ray spectra from the 3XMM and the XMMFITCAT catalogs. Implementing various indicators of obscuration, we find seven (~23%) Compton-thick AGN. The X-ray spectroscopic Compton-thick classification agrees with other commonly used diagnostics, such as the X-ray to mid-IR luminosity ratio and the X-ray to [OIII] luminosity ratio. Most importantly, we find four (~13%) unobscured Sy2 galaxies, at odds with the simplest unification model. Their accretion rates are significantly lower than the rest of our Sy2 sample, in agreement with previous studies that predict the absence of the broad line region below a certain Eddington ratio threshold.Comment: 12 pages, 6 figures, accepted for publication in A&

Teleparallel origin of the Fierz picture for spin-2 particle

A new approach to the description of spin-2 particle in flat and curved spacetime is developed on the basis of the teleparallel gravity theory. We show that such an approach is in fact a true and natural framework for the Fierz representation proposed recently by Novello and Neves. More specifically, we demonstrate how the teleparallel theory fixes uniquely the structure of the Fierz tensor, discover the transparent origin of the gauge symmetry of the spin 2 model, and derive the linearized Einstein operator from the fundamental identity of the teleparallel gravity. In order to cope with the consistency problem on the curved spacetime, similarly to the usual Riemannian approach, one needs to include the non-minimal (torsion dependent) coupling terms.Comment: 5 pages, Revtex4, no figures. Accepted for publication in Phys. Rev.

Variable broad lines and outflow in the weak blazar PBC J2333.9-2343

Indexación: Scopus; Scielo.Funding text #1 1Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile 2INAF – Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS-INAF), Via del Fosso del Cavaliere 100, I-00133 Roma, Italy 3INAF – Osservatorio Astronomico di Roma, via Frascati 33, I-00078 Monte Porzio Catone, Italy 4Excellence Cluster Universe, Technische Universität München, Boltzmannstr. 2, D-85748, Garching, Germany 5European Southern Observatory, Karl-Schwarzschild-Str 2, D-85748 Garching b. München, Germany 6Instituto Nacional de Astrofísica, Óptica y Electrónica, Apartado Postal 51-216, 72000 Puebla, México 7Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany 8International Max Planck Research School of Astronomy and Astrophysics at the Universities of Bonn and Cologne, Auf dem Hügel 69, D-53121 Bonn, Germany 9INAF – Osservatorio di Astrofisica e Scienza dello Spazio, via Gobetti 93/3, I-40129 Bo...View all Funding text #2 We acknowledge the referee, M. Villar Martín, for her comments and suggestions that helped to improve the paper. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester, the NASA/IPAC extragalactic database (NED), the STARLIGHT code, and the IRAF software. Based upon observations carried out at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir (OAN-SPM), Baja California, México. LHG and FP acknowledge the ASI/INAF agreement number 2013-023-R1, LHG partial support from FONDECYT through grant 3170527, MP from ESSTI under the MoST, and from MINECO through research projects AYA2013-42227-P and AYA2016-76682-C3-1-P (AEI/FEDER, UE), LHG and SC from the Spanish grant AYA2013-42227-P, VC by CONACyT research grant 280789, EFJA from the Collaborative Research Center 956, subproject A1, funded by DFG, and GV from the DFG Cluster of Excellence ‘Origin and Structure of the Universe’ (www.universe-cluster.de).PBC J2333.9-2343 is a peculiar active nucleus with two giant radio lobes and a weak blazarlike nucleus at their centre. In this work we show new optical, ultraviolet (UV), and X-ray data taken from the San Pedro Mártir telescope, the New Technology Telescope, NTT/EFOSC2, and the Swift/XRT satellite. The source is highly variable at all frequencies, in particular the strongest variations are found in the broad Hα component with a flux increase of 61±4 per cent between 2009 and 2016, following the X-ray flux increase of 62±6 per cent between 2010 and 2016. We also detected a broad Hβ component in 2016, making the optical classification change from type 1.9 to type 1.8 in 1 yr. We have also detected a broad component of the [OIII]λ5007 line, which is blue-shifted and of high velocity, suggesting an origin from a highly disturbed medium, possibly an outflow. The line flux variability and broad widths are indicative of a jet that is, at least in part, responsible for the ionization of the broad line region (BLR) and narrow line region (NLR). © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.https://academic.oup.com/mnras/article-abstract/478/4/4634/4999938?redirectedFrom=fulltex

Modificações na paisagem da região de Petrolina/Juazeiro do Rio São Francisco.

Ao longo do tempo, as alterações da paisagem às margens do rio São Francisco foram intensas. A análise da dinâmica do uso e cobertura da terra permite entender essas modificações. Neste trabalho objetivou&#8208;se estudar a dinâmica da paisagem na Região Integrada de Desenvolvimento (RIDE) do Pólo Petrolina&#8208;PE e Juazeiro. Foram obtidas cenas Landsat 5 ? TM dos anos de 1987 a 2008 para os municípios de Petrolina, Lagoa Grande, Santa Maria da Serra e Orocó (Pernambuco) e Juazeiro, Casa Nova, Sobradinho e Curaçá (Bahia). Para classificação, as cenas foram segmentadas e interpretadas em conjunto com informações complementares do PROBIO, NDVI, imagens de alta resolução espacial e visitas a campo. Os resultados mostram que 9,7% (2.900 km2) da Caatinga foi convertida em pastagem, agricultura irrigada e expansão urbana. A diminuição da conectividade entre fragmentos de vegetação são marcantes na região. Grande parte das chácaras ribeirinhas não preservam suas margens e utilizam intensamente suas terras principalmente para agricultura irrigada. Dentre os municípios da RIDE, Curaçá, BA, foi o município que manteve maior porcentagem de área preservada

Dinâmica da paisagem no submédio do rio São Francisco.

O uso e a cobertura das terras nas margens do Rio São Francisco foram muito alterados ao longo do tempo, o que modificou a sua fitofisionomia original. Assim, neste trabalho objetivou-se estudar a dinâmica da paisagem na região do Submédio do Rio São Francisco por meio de imagens Landsat 5 – TM dos anos de 1987 a 2008 da Região Integrada de Desenvolvimento (RIDE) do Polo Petrolina, PE, e Juazeiro, BA. Para a classificação, as imagens foram segmentadas e interpretadas em conjunto com informações complementares do PROBIO, NDVI, imagens de alta resolução espacial e visitas a campo. Os resultados mostraram que 9,7% (2.900 km2) da área de Caatinga foi convertida em pastagem, agricultura irrigada e expansão urbana em 21 anos. A diminuição da conectividade entre fragmentos de vegetação é marcante na região. Grande parte das chácaras ribeirinhas não preserva suas margens e utiliza intensamente suas terras, principalmente para agricultura irrigada. Entre os municípios da RIDE, Curaçá, BA, foi o que manteve a maior porcentagem de área.bitstream/item/58157/1/029-11.pd