13,587 research outputs found
Earth-based lunar atmosphere investigation Final report
Instrumentation and results of earth-based spectrometric identification of lunar atmospheric constituents in visible regio
On the Evaluation of the Mechanical Behaviour of Structural Glass Elements
Glass can be considered to be a high-technology engineering material with a
multifunctional potential for structural applications. However, the conventional approach to the use
of glass is often based only on its properties of transparency and isolation. It is thus highly
appropriate and necessary to study the mechanical behaviour of this material and to develop
adequate methods and models leading to its characterisation. It is evident that the great potential of
growth for structural glass applications is an important opportunity of development for the glass
industry and the building/construction sectors. The work presented in this paper is a reflection of
this conclusion. The authors shortly present the state-of-the-art on the application of glass as a
structural element in building and construction, and refer to other potential fields of application and
available glass materials. The experimental procedures and methods adopted in three-point bending
tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with
thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical
strength and stiffness of glass for structural applications. This work contributes to a deeper
knowledge of the properties of this material
Random Antiferromagnetic SU(N) Spin Chains
We analyze random isotropic antiferromagnetic SU(N) spin chains using the
real space renormalization group. We find that they are governed at low
energies by a universal infinite randomness fixed point different from the one
of random spin-1/2 chains. We determine analytically the important exponents:
the energy-length scale relation is , where
, and the mean correlation function is given by
, where . Our analysis shows
that the infinite-N limit is unable to capture the behavior obtained at any
finite N.Comment: 4 pages, 3 figure
Recomendações para inoculação e peletizacao de sementes de leguminosas forrageiras tropicais.
Este trabalho teve por objetivo testar um produto adesivo de fácil obtenção e baixo preço, bem como verificar a adequação dos fosfatos de rocha regionais para formação de "pelets" e sua influência na sobrevivência do inoculante, aplicado a semente de diversas leguminosas forrageiras tropicais de interesse regional. Os resultados obtidos permitiram elaborar recomendações praticas (Tabela 2) que se encontram anexas.bitstream/item/138503/1/COT-17.pdfCNPG
Vector meson quasinormal modes in a finite-temperature AdS/QCD model
We study the spectrum of vector mesons in a finite temperature plasma. The
plasma is holographically described by a black hole AdS/QCD model. We compute
the boundary retarded Green's function using AdS/CFT prescriptions. The
corresponding thermal spectral functions show quasiparticle peaks at low
temperatures. Then we calculate the quasinormal modes of vector mesons in the
soft-wall black hole geometry and analyse their temperature and momentum
dependences.Comment: 27 pages, 9 figure
Planejamento da atividade leiteira: sugestões para os produtores iniciantes.
bitstream/item/65443/1/COT-56-Planejamento-da-atividade.pd
Investigation of gut microbiome association with inflammatory bowel disease and depression: A machine learning approach
Background: Inflammatory bowel disease (IBD) is a group of chronic diseases related to inflammatory processes in the digestive tract generally associated with an immune response to an altered gut microbiome in genetically predisposed subjects. For years, both researchers and clinicians have been reporting increased rates of anxiety and depression disorders in IBD, and these disorders have also been linked to an altered microbiome. However, the underlying pathophysiological mechanisms of comorbidity are poorly understood at the gut microbiome level. Methods: Metagenomic and metatranscriptomic data were retrieved from the Inflammatory Bowel Disease Multi-Omics Database. Samples from 70 individuals that had answered to a self-reported depression and anxiety questionnaire were selected and classified by their IBD diagnosis and their questionnaire results, creating six different groups. The cross-validation random forest algorithm was used in 90% of the individuals (training set) to retain the most important species involved in discriminating the samples without losing predictive power. The validation set that represented the remaining 10% of the samples equally distributed across the six groups was used to train a random forest using only the species selected in order to evaluate their predictive power. Results: A total of 24 species were identified as the most informative in discriminating the 6 groups. Several of these species were frequently described in dysbiosis cases, such as species from the genus Bacteroides and Faecalibacterium prausnitzii. Despite the different compositions among the groups, no common patterns were found between samples classified as depressed. However, distinct taxonomic profiles within patients of IBD depending on their depression status were detected. Conclusions: The machine learning approach is a promising approach for investigating the role of microbiome in IBD and depression. Abundance and functional changes in these species suggest that depression should be considered as a factor in future research on IBD
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies
Desenvolvimento de plantas jovens de coqueiro anão (Cocos nucifera L.) submetidas a diferentes regimes de irrigação.
O deficit hidrico no solo, causado pela ma distribuicao das precipitacoes ao longo do ano, constitui um dos principais fatores que contribuem para a baixa produtividade do coqueiro nas diferentes regioes onde e cultivado. Devido a isto, tem aumentado significativamente nos ultimos anos o uso da irrigacao nessa cultura, sobretudo nos plantios do coqueiro anao, cujos frutos se destinam ao crescente mercado de agua de coco, "in natura".bitstream/CNPAT-2010/5373/1/Pa-023.pd
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