715 research outputs found

    CARACTERIZAÇÃO DAS UNIDADES GEOAMBIENTAIS E CONDIÇÕES DE USO E COBERTURA DO ESTUÁRIO DO RIO ARACATIAÇU/CE

    Get PDF
    O ambiente estuarino é um ponto de encontro entre as águas continentais e marinhas, proporcionando assim um ambiente de intensas dinâmicas físico-químicas e biológicas. Este estudo teve por objetivo caracterizar, a partir da análise integrada, as condições geoambientais atuais e o uso e cobertura do estuário do rio Aracatiaçu, localizado no município de Amontada, na costa oeste do estado do Ceará

    Scanning Fourier Spectroscopy: A microwave analog study to image transmission paths in quantum dots

    Full text link
    We use a microwave cavity to investigate the influence of a movable absorbing center on the wave function of an open quantum dot. Our study shows that the absorber acts as a position-selective probe, which may be used to suppress those wave function states that exhibit an enhancement of their probability density near the region where the impurity is located. For an experimental probe of this wave function selection, we develop a technique that we refer to as scanning Fourier spectroscopy, which allows us to identify, and map out, the structure of the classical trajectories that are important for transmission through the cavity.Comment: 4 pages, 5 figure

    Reactive phenotypes after acute and chronic NK‐cell activation

    Get PDF
    J Biol Regul Homeost Agents. 2004 Jul-Dec;18(3-4):331-4. Reactive phenotypes after acute and chronic NK-cell activation. Lima M, Almeida J, Teixeira MA, Santos AH, Queirós ML, Fonseca S, Moura J, Gonçalves M, Orfão A, Pinto Ribeiro AC. Service of Clinical Hematology, Laboratory of Cytometry, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract Several phenotypic changes have been shown to occur after NK-cell stimulation, involving molecules that have been proved to regulate NK-cell migration into tissues and NK-cell activation and proliferation as well as target cell recognition and killing. Here, we review the reactive phenotypes observed in vivo after acute and chronic NK-cell activation. PMID: 15786700 [PubMed - indexed for MEDLINE

    3-amino-1,2,4-triazole induces quick and strong fat loss in mice with high fat-induced metabolic syndrome

    Get PDF
    BACKGROUND: Obesity is a growing epidemic with limited effective treatments and an important risk factor for several diseases such as metabolic syndrome (MetS). In this study, we aimed to investigate the effect of 3-amino-1,2,4-triazole (ATZ), an inhibitor of catalase and heme synthesis, in a murine model for MetS. METHODS: Male C57BL/6 mice with high-fat diet-induced MetS received ATZ (500 mg·kg(-1)·24 h(-1)) for 12 weeks. RESULTS: The HFD group showed increased blood pressure and body weight, enhanced fat deposition accompanied by an increase in adipocyte diameter, and decreased lipolysis in white adipose tissue (WAT). The expression of genes related to inflammation was increased in WAT of the HFD group. Concurrently, these mice exhibited an increase in leptin, nonesterified fatty acid (NEFA), insulin, and glucose in plasma, coupled with glucose intolerance and insulin resistance. Strikingly, ATZ prevented the increase in blood pressure and the HFD-induced obesity as observed by lower body weight, WAT index, triglycerides, NEFA, and leptin in plasma. ATZ treatment also prevented the HFD-induced increase in adipocyte diameter and even induced marked atrophy and the accumulation of macrophages in this tissue. ATZ treatment also improved glucose metabolism by increasing glucose tolerance and insulin sensitivity, GLUT4 mRNA expression in WAT in parallel to decreased insulin levels. CONCLUSIONS: In the context of HFD-induced obesity and metabolic syndrome, the fat loss induced by ATZ is probably due to heme synthesis inhibition, which blocks adipogenesis by probably decreased RevErbα activity, leading to apoptosis of adipocytes and the recruitment of macrophages. As a consequence of fat loss, ATZ elicits a beneficial systemic antiobesity effect and improves the metabolic status

    Rochas xistentas de Trás-os-Montes como recurso

    Get PDF
    The abundance of schist outcrops in the Northeast and Centre regions of Portugal made schist, in the past, a common building material. A FCT R&D project is in course aiming the structural, mineralogical, petrographycal and technological characterization of the schist occurrences in NE Portugal and the promotion of those schistose rocks as a geological resource. In this contribution, we present three cases corresponding to different geological context and different characteristics, Nozelos (Torre de Moncorvo), Alto das Pedreiras (Deilão, Bragança) and Zebras (Valpaços

    Comment on "Critique of q-entropy for thermal statistics" by M. Nauenberg

    Full text link
    It was recently published by M. Nauenberg [1] a quite long list of objections about the physical validity for thermal statistics of the theory sometimes referred to in the literature as {\it nonextensive statistical mechanics}. This generalization of Boltzmann-Gibbs (BG) statistical mechanics is based on the following expression for the entropy: S_q= k\frac{1- \sum_{i=1}^Wp_i^q}{q-1} (q \in {\cal R}; S_1=S_{BG} \equiv -k\sum_{i=1}^W p_i \ln p_i) . The author of [1] already presented orally the essence of his arguments in 1993 during a scientific meeting in Buenos Aires. I am replying now simultaneously to the just cited paper, as well as to the 1993 objections (essentially, the violation of "fundamental thermodynamic concepts", as stated in the Abstract of [1]).Comment: 7 pages including 2 figures. This is a reply to M. Nauenberg, Phys. Rev. E 67, 036114 (2003

    Quasinormal modes for tensor and vector type perturbation of Gauss Bonnet black holes using third order WKB approach

    Full text link
    We obtain the quasinormal modes for tensor perturbations of Gauss-Bonnet (GB) black holes in d=5,7,8d=5, 7, 8 dimensions and vector perturbations in d=5,6,7d = 5, 6, 7 and 8 dimensions using third order WKB formalism. The tensor perturbation for black holes in d=6d=6 is not considered because of the fact that it is unstable to tensor mode perturbations. In the case of uncharged GB black hole, for both tensor and vector perturbations, the real part of the QN frequency increases as the Gauss-Bonnet coupling (α\alpha') increases. The imaginary part first decreases upto a certain value of α\alpha' and then increases with α\alpha' for both tensor and vector perturbations. For larger values of α\alpha', the QN frequencies for vector perturbation differs slightly from the QN frequencies for tensorial one. It has also been shown that as α0\alpha' \to 0, the quasinormal mode frequency for tensor and vector perturbation of the Schwarzschild black hole can be obtained. We have also calculated the quasinormal spectrum of the charged GB black hole for tensor perturbations. Here we have found that the real oscillation frequency increases, while the imaginary part of the frequency falls with the increase of the charge. We also show that the quasinormal frequencies for scalar field perturbations and the tensor gravitational perturbations do not match as was claimed in the literature. The difference in the result increases if we increase the GB coupling.Comment: 17 pages, 11 figures, change in title and abstract, new equations and results added for QN frequencies for vector perturbations, new referencees adde

    Critical Behavior of the Supersolid transition in Bose-Hubbard Models

    Full text link
    We study the phase transitions of interacting bosons at zero temperature between superfluid (SF) and supersolid (SS) states. The latter are characterized by simultaneous off-diagonal long-range order and broken translational symmetry. The critical phenomena is described by a long-wavelength effective action, derived on symmetry grounds and verified by explicit calculation. We consider two types of supersolid ordering: checkerboard (X) and collinear (C), which are the simplest cases arising in two dimensions on a square lattice. We find that the SF--CSS transition is in the three-dimensional XY universality class. The SF--XSS transition exhibits non-trivial new critical behavior, and appears, within a d=3ϵd=3-\epsilon expansion to be driven generically first order by fluctuations. However, within a one--loop calculation directly in d=2d=2 a strong coupling fixed point with striking ``non-Bose liquid'' behavior is found. At special isolated multi-critical points of particle-hole symmetry, the system falls into the 3d Ising universality class.Comment: RevTeX, 24 pages, 16 figures. Also available at http://www.cip.physik.tu-muenchen.de/tumphy/d/T34/Mitarbeiter/frey.htm

    On the Number of Zeros of Abelian Integrals: A Constructive Solution of the Infinitesimal Hilbert Sixteenth Problem

    Full text link
    We prove that the number of limit cycles generated by a small non-conservative perturbation of a Hamiltonian polynomial vector field on the plane, is bounded by a double exponential of the degree of the fields. This solves the long-standing tangential Hilbert 16th problem. The proof uses only the fact that Abelian integrals of a given degree are horizontal sections of a regular flat meromorphic connection (Gauss-Manin connection) with a quasiunipotent monodromy group.Comment: Final revisio
    corecore