225 research outputs found
Gravitational Potential Energy in Iberia: A Driver of Active Deformation in High‐Topography Regions
In this study, we present a new estimation of the gravitational potential energy (GPE) in Iberia and use numerical modeling to evaluate its relative contribution to the present‐day stress field and deformation. We also present an improved (larger time span and denser coverage) compilation of Global Navigation Satellite System velocities, which we use to compute the strain rate field of Iberia. We take advantage of recent neotectonic modeling developed for Iberia and northwest Africa to study the isolated dynamic contribution of GPE‐related stresses. We present two models—one including only the stress generated by GPE and another reproducing the net stress field—and compare their predictions with the most up‐to‐date compilations of stress indicators, hypocenter clusters, and geodetic strain rates. The main effect of GPE is to induce second‐order spatial variations in the stress field. GPE appears to play an important role in high‐topography regions, where it explains deviatoric stress patterns mainly associated with extensional regimes. In north Iberia, especially in the Pyrenees and Cantabria, GPE causes an extensional regime over the highest peaks. In the Iberian Chain and eastern Betics, GPE is in agreement with the observed extensional deformation. Normal focal mechanisms of shallow earthquake clusters appear to be related with GPE maxima and GPE‐induced extensional regimes. Wavelength analysis suggests that both GPE and the long‐wavelength topography of intraplate Iberia record the plate boundary forces that acted in Iberia during the Alpine orogeny at Eocene to lower Miocene times
Produção de forragem pela aveia preta (Avena strigosa L.) em cultivo solteiro ou consorciado com cornichão (Lotus corniculatus L.).
ZOOTEC
Identificação das fontes de crescimento da produção de leite na Região Norte do Brasil, 1990-2011.
O presente trabalho identifica as fontes de crescimento da produção de leite na Região Norte do Brasil, no período 1990-2011, e decompõe o crescimento da produção, nos efeitos expansão do rebanho e produtividade animal. Foram estimadas as taxas de crescimento da produção, plantel de vacas ordenhadas e produtividade animal, por meio de regressão linear, com emprego de modelo semilogarítmico. A produção regional cresceu a taxa de 6,2% ao ano, com predominância do efeito expansão do rebanho, cuja taxa de crescimento foi de 3,3% ao ano, enquanto o crescimento da produtividade animal foi de 2,9% ao ano. Em quatro dos sete estados que compõe a Região Norte ocorreu crescimento da produtividade animal superior ao do rebanho, o que sinaliza avanços na adoção de tecnologias nos sistemas de produção
Magnetic and Sedimentological data as a contribution for mass transport deposits identification on Southern Portuguese Margin
Formation of Mass Transport Deposits on the Submarine Bank of Portimão (Gulf of Cadiz, SW Iberia)
European Geosciences Union General Assembly (2017. Viena)The development of submarine mass transport deposits (MTDs) plays an important geo-hazards role along continental margins. Accordingly, their identification and characterization is crucial to understand their sources, dynamics, frequency and spatial distribution. In this work a piston core located at the slope (2876 m water depth) of the southern flank of Portimao Bank (Portugal, Gulf of Cadiz, SW Iberia) underwent detailed magnetic (fabric and rock magnetism) and sedimentological (grain-size, carbonates, organic matter) analyses complemented by AMS 14C dating. Such multidisciplinary study identified about one meter of sediments that is unconformable with the ages obtained above and below this layer. Its magnetic fabric, as determined by anisotropy of magnetic
susceptibility, indicates sharply changes from oblate to neutral shape, decrease of the anisotropy and preferred orientation of the magnetic susceptibility ellipsoid. Such layer is also individualized by sedimentary parameters, especially in its upper part by a lighter colour and decrease of the mean grain size than the rest of the core. Based on these results it is possible to conclude that the sedimentary column analyzed here shows evidence of an on-going development of a slide, which is well individualized and characterized by magnetic fabric studies.Instituto Dom Luiz, University of Lisbon, PortugalInstituto Superior de Engenharia de Lisboa, PortugalEstrutura de Missão para a Extensão da Plataforma Continental, PortugalInstituto Português do Mar e da Atmosfera, PortugalInstituto de Ciencias del Mar, Consejo Superior de Investigaciones Científicas, EspañaCentro Oceanográfico de Málaga, Instituto Español de Oceanografía, EspañaInstituto Geológico y Minero de España, Españ
Zonación vertical de la bioturbación y movimientos en masa en el Banco de Portimão (Golfo de Cádiz, SO de Iberia)
This work presents results from bioturbation intensity and trace fossil analysis of the piston
core PC07, recovered at Portimão Bank during the MONTERA cruise in 2012. The aim was to
investigate the potential of bioturbation analysis as an indicator for mass movement events.
Bioturbation and trace fossil identification was complemented with results from sedimentological
analysis (grain-size, carbonates, organic matter), measurements of magnetic fabric parameters (mass
magnetic susceptibility and anisotropy of magnetic susceptibility), and AMS 14C dating. Considering
the vertical zonation of bioturbation, magnetic fabric changes, sedimentology and AMS radiocarbon
dating, two intervals were identified, Interval A (0-180 cm) and Interval B (180-356 cm), being the
limit between them placed at 180-181cm. These intervals seem to replicate almost the same vertical
zonation of bioturbation and the trend of carbonates and organic matter changes downcore. The
magnetic fabric parameters (degree of anisotropy – Pj and shape – T of the magnetic susceptibility
ellipsoid) show the major change at about 180 cm. Geochronological results indicate that the age of
sediments in Interval A is 8590 yr BP (31-32 cm) and 14 300 yr BP (103-104 cm). Otherwise, ages in
Interval B are the following: 5035 yr BP (181-182 cm), 8900±50 yr BP (219-220 cm), 18999±120 yr BP
(303-305 cm). These results point to the emplacement of sediments of Interval A on top of youngest
sediments of Interval due to landsliding. Since no internal deformation is seen, probably this
indicates translational movement and short transport from the source.Versión del edito
OCORRÊNCIA DA FAMÍLIA LORANTHACEAE NO MUNICÍPIO DE CAXIAS, MARANHÃO, BRASIL
As espécies pertencentes à família Loranthaceae são plantas perenes, com folhas sempre verdes. Estão distribuídas em regiões tropicais e subtropicais, compreendendo aproximadamente 70 gêneros e 950 espécies. O objetivo deste estudo foi realizar um levantamento de espécies de ervas-de-passarinho da família Loranthaceae no município de Caxias (MA). As coletas foram realizadas nos meses de maio de 2007 a setembro de 2008 na zona urbana e rural do município de Caxias, seguindo as técnicas usais para este tipo de trabalho. Foram coletados 29 espécimes, onde a espécie com maior representatividade foi a Phthirusa pyrifolia, correspondendo a 31,03% das espécies encontradas. Esse resultado deve-se ao fato de que essa espécie é do tipo generalista, podendo parasitar uma diversidade de hospedeiros
Perfil de ácidos graxos de carne de búfalos terminados em sistemas tradicional e silvipastoril.
The aim of this study was to evaluate the fatty acid profile of the meat of buffalo finished in creating Traditional Systems (ST) and Silvopastoral (SSP) with supplemental feeding. The experiments were performed in the Research Units Animal "Senator Álvaro Adolpho", silvopastoral system and "Dr. Philibert Camargo, "traditional system of creation, belonging to Embrapa Amazônia Oriental, Belém-Pará, Brazil. After the fattening period, eight months, the animals were slaughtered at a commercial abattoir and their carcasses identified, refrigerated for 24 hours. The Longissimus dorsi (kebabs) retained the right half carcass between the 12th and 10th ribs, was ground and stored for determination of acids in lipids extracted from samples and cold reading esters performed by gas chromatography. The experimental design was completely randomized, the data were evaluated by ANOVA and means were compared by 't' test at 5% significance level. The analysis of fatty acid profile reveals a statistical difference (P <0.05), only the percentage of myristic acid (C14: 0) and polyunsaturated fatty acids. In conclusion, therefore, that breeding systems and supplementation are not sufficient to indicate the use of either system, since it must be taken into account also the environmental, social and economic
Evaluation of the Antimicrobial Activity of Cationic Polymers against Mycobacteria: Toward Antitubercular Macromolecules.
Antimicrobial resistance is a global healthcare problem with a dwindling arsenal of usable drugs. Tuberculosis, caused by Mycobacterium tuberculosis, requires long-term combination therapy and multi- and totally drug resistant strains have emerged. This study reports the antibacterial activity of cationic polymers against mycobacteria, which are distinguished from other Gram-positive bacteria by their unique cell wall comprising a covalently linked mycolic acid-arabinogalactan-peptidoglycan complex (mAGP), interspersed with additional complex lipids which helps them persist in their host. The present study finds that poly(dimethylaminoethyl methacrylate) has particularly potent antimycobacterial activity and high selectivity over two Gram-negative strains. Removal of the backbone methyl group (poly(dimethylaminoethyl acrylate)) decreased antimycobacterial activity, and poly(aminoethyl methacrylate) also had no activity against mycobacteria. Hemolysis assays revealed poly(dimethylaminoethyl methacrylate) did not disrupt red blood cell membranes. Interestingly, poly(dimethylaminoethyl methacrylate) was not found to permeabilize mycobacterial membranes, as judged by dye exclusion assays, suggesting the mode of action is not simple membrane disruption, supported by electron microscopy analysis. These results demonstrate that synthetic polycations, with the correctly tuned structure are useful tools against mycobacterial infections, for which new drugs are urgently required
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