612 research outputs found
Equivariant cohomology over Lie groupoids and Lie-Rinehart algebras
Using the language and terminology of relative homological algebra, in
particular that of derived functors, we introduce equivariant cohomology over a
general Lie-Rinehart algebra and equivariant de Rham cohomology over a locally
trivial Lie groupoid in terms of suitably defined monads (also known as
triples) and the associated standard constructions. This extends a
characterization of equivariant de Rham cohomology in terms of derived functors
developed earlier for the special case where the Lie groupoid is an ordinary
Lie group, viewed as a Lie groupoid with a single object; in that theory over a
Lie group, the ordinary Bott-Dupont-Shulman-Stasheff complex arises as an a
posteriori object. We prove that, given a locally trivial Lie groupoid G and a
smooth G-manifold f over the space B of objects of G, the resulting
G-equivariant de Rham theory of f boils down to the ordinary equivariant de
Rham theory of a vertex manifold relative to the corresponding vertex group,
for any vertex in the space B of objects of G; this implies that the
equivariant de Rham cohomology introduced here coincides with the stack de Rham
cohomology of the associated transformation groupoid whence this stack de Rham
cohomology can be characterized as a relative derived functor. We introduce a
notion of cone on a Lie-Rinehart algebra and in particular that of cone on a
Lie algebroid. This cone is an indispensable tool for the description of the
requisite monads.Comment: 47 page
Estado Da Arte Da Literatura Científica Sobre Hancornia Speciosa: Tendências E Lacunas
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The economic and scientific interest in Hancornia speciosa (mangabeira) has been growing in recent years, mainly due to the marketing of fruit and extraction of natural compounds with high pharmacological potential. In this study, a scientometric survey about mangabeira was carried out in order to promote and direct future studies on the species. As a result, low scientific productivity associated with this species was found, with only 131 articles published in the last 69 years. In addition, this study identified some trends in bibliographic production on mangabeira, among them: the increasing number of articles over the years; scientific dissemination in nationwide journals; the main focus of this study is associated with agronomic studies; the experimental approach is more frequent and usually associated with populations of restricted geographical distribution; and the scientific production is mainly from education institutions. Furthermore, this study also allowed the identification of some gaps in knowledge about mangabeira, among them the difficulty in describing and characterizing botanical lines; lack of analysis of the genetic diversity of widely distributed populations; lack of management and conservation projects for the species; lack of description of cultivation, collection and preservation techniques of fruits; and lack of identification of natural compounds responsible for its pharmacological activity. It is expected that the data generated in this study will serve to direct future studies on H. speciosa. © 2016, Sociedade Brasileira de Fruticultura. All rights reserved.384CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEG, Fundação de Amparo à Pesquisa do Estado de GoiásFINEP, Financiadora de Estudos e ProjetosCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Genetic characterization of interleukins (IL-1α, IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12A, IL-12B, IL-15 and IL-18) with relevant biological roles in lagomorphs
Disponível em: www.ncbi.nlm.nih.gov/pmc/articles/pmid/26395994/ILs, as essential innate immune modulators, are involved in an array of biological processes. In the European rabbit (Oryctolagus cuniculus) IL-1α, IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12A, IL-12B, IL-15 and IL-18 have been implicated in inflammatory processes and in the immune response against rabbit hemorrhagic disease virus and myxoma virus infections. In this study we characterized these ILs in six Lagomorpha species (European rabbit, pygmy rabbit, two cottontail rabbit species, European brown hare and American pika). Overall, these ILs are conserved between lagomorphs, including in their exon/intron structure. Most differences were observed between leporids and American pika. Indeed, when comparing both, some relevant differences were observed in American pika, such as the location of the stop codon in IL-1α and IL-2, the existence of a different transcript in IL8 and the number of cysteine residues in IL-1β. Changes at N-glycosylation motifs were also detected in IL-1, IL-10, IL-12B and IL-15. IL-1α is the protein that presents the highest evolutionary distances, which is in contrast to IL-12A where the distances between lagomorphs are the lowest. For all these ILs, sequences of human and European rabbit are more closely related than between human and mouse or European rabbit and mouse.Research Subject Categories::NATURAL SCIENCES::Biology::Cell and molecular biology::ImmunologyResearch Subject Categories::NATURAL SCIENCES::Biology::Cell and molecular biology::GeneticsFCT and North Portugal Regional Operational Programme 2007/2013 (ON.2) grants supported this work
Superregular matrices and applications to convolutional codes
The main results of this paper are twofold: the first one is a matrix theoretical result. We say that a matrix is superregular if all of its minors that are not trivially zero are nonzero. Given a a×b, a ≥ b, superregular matrix over a field, we show that if all of its rows are nonzero then any linear combination of its columns, with nonzero coefficients, has at least a−b + 1 nonzero entries. Secondly, we make use of this result to construct convolutional codes that attain the maximum possible distance for some fixed parameters of the code, namely, the rate and the Forney indices. These results answer some open questions on distances and constructions of convolutional codes posted in the literature
Domain adaptation with cyclegan for change detection in the amazon forest
Deep learning classification models require large amounts of labeled training data to perform properly, but the production of reference data for most Earth observation applications is a labor intensive, costly process. In that sense, transfer learning is an option to mitigate the demand for labeled data. In many remote sensing applications, however, the accuracy of a deep learning-based classification model trained with a specific dataset drops significantly when it is tested on a different dataset, even after fine-tuning. In general, this behavior can be credited to the domain shift phenomenon. In remote sensing applications, domain shift can be associated with changes in the environmental conditions during the acquisition of new data, variations of objects' appearances, geographical variability and different sensor properties, among other aspects. In recent years, deep learning-based domain adaptation techniques have been used to alleviate the domain shift problem. Recent improvements in domain adaptation technology rely on techniques based on Generative Adversarial Networks (GANs), such as the Cycle-Consistent Generative Adversarial Network (CycleGAN), which adapts images across different domains by learning nonlinear mapping functions between the domains. In this work, we exploit the CycleGAN approach for domain adaptation in a particular change detection application, namely, deforestation detection in the Amazon forest. Experimental results indicate that the proposed approach is capable of alleviating the effects associated with domain shift in the context of the target application. © 2020 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives
Three-dimensional modelling of an embankment built on a soft soil improved with prefabricated vertical drains
This work compares the field measurements of a non-symmetric embankment built on a Portuguese soft soil improved with prefabricated vertical drains (PVDs), with the numerical predictions of a 3D modelling where the PVDs are simulated according to the field flow conditions. The change in the permeability with the void ratio and the effect of the smear zone are also included in the numerical analysis. The numerical predictions are compared with the field data in terms of settlement, horizontal displacement and excess pore pressure. In general, the numerical results are very close to the field measurements, namely in terms of vertical and horizontal deformations
Long-lived oscillons from asymmetric bubbles
The possibility that extremely long-lived, time-dependent, and localized
field configurations (``oscillons'') arise during the collapse of asymmetrical
bubbles in 2+1 dimensional phi^4 models is investigated. It is found that
oscillons can develop from a large spectrum of elliptically deformed bubbles.
Moreover, we provide numerical evidence that such oscillons are: a) circularly
symmetric; and b) linearly stable against small arbitrary radial and angular
perturbations. The latter is based on a dynamical approach designed to
investigate the stability of nonintegrable time-dependent configurations that
is capable of probing slowly-growing instabilities not seen through the usual
``spectral'' method.Comment: RevTeX 4, 9 pages, 11 figures. Revised version with a new approach to
stability. Accepted to Phys. Rev.
Avaliação Da Produção De Látex Em Mangabeiras Do Cerrado Goiano
The mangabeira latex, plant native from Cerrado, shows biotechnological potential for the development of new drugs. Little is known about the latex productivity and bleeding methods in mangabeira, which is usually utilized in extractive way for fruit production. Aiming to broaden our knowledge about mangabeira latex production we evaluate the productivity associated with bleeding methods; environmental conditions; anatomical aspects from the bark and seasonal properties. As results we observed that the bleeding method commonly used in rubber tree is not appropriated to mangabeira; the most productive bleeding method was using a knife in stalk region. The bark thickness and lactiferous vessels number are associated with latex production. Anatomical analysis showed that the bark in mangabeira is thick and the lactiferous vessels are deeply localized, in this way some superficial bleeding methods are not able to reach the vessels. It was also observed that the increase in environmental temperature has a positive influence on the productivity of latex and that during the fruiting time the latex production is significantly lower. This probably occurs because the plant uses part of the secondary metabolites for fruit formation, which reduced the availability of these metabolites to latex production. © 2016, Universidade Federal de Santa Maria. All rights reserved.26393994
Passivation and dissolution mechanisms in ordered anodic tantalum oxide nanostructures
Tantalum oxide (Ta2O5) nanostructures exhibit outstanding electrical and optical properties, as well as, high chemical resistance and stability. These materials have great potential for biomedical, catalysis, semiconductors and energy applications due to their large surface area and high specific charge, when arranged in nanoporous or nanotubular morphologies. In order to obtain these structures, an anodization process, which is inexpensive, reproducible and easy to scale up, is used. Yet, depending on the anodization conditions, the formation of a nanoporous or nanotubular layer is difficult to stabilize during the anodization process. In this regard, anodized tantalum oxide nanostructures were produced to understand the effect of the anodization conditions, including electrolyte concentration, potential and time. The nanopores or nanotubes morphologies, their chemical composition and structure were investigated by FIB-SEM, double-corrected TEM-STEM and EDS. We found that it is necessary to have high acid concentrations (mixture of H2SO4 with HF) to be able to form nanoporous or nanotubular structures. Despite the capacity of HF to dissolve and create anodic oxide nanostructures, the amount of H2SO4 concentration in the mixture is very important, leading to a dimple morphology. Furthermore, the increase of the anodization potential/electrical field clearly leads to an increase in the dimples diameter.This research is sponsored by FEDER funds through the program COMPETE -Programa Operacional Factores de Competitividade and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020, and UID/EMS/00285/2020 and with a PhD fellowship SFRH/BD/98199/2013.The authors thank the financial support in the framework of HEALTHYDENT -POCI-01-0145-FEDER-030708 and PTDC/CTM-NAN/4242/2014 projects.This work was supported by FCT, through IDMEC, under LAETA, project UIDB/50022/2020.The authors would like to acknowledge that this project has received funding from the EU Framework Programme for Research and Innovation H2020, scheme COFUND -Co-funding of Regional, National and International Programmes, under Grant Agreement 713640
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