715 research outputs found
CARACTERIZAÇÃO DAS UNIDADES GEOAMBIENTAIS E CONDIÇÕES DE USO E COBERTURA DO ESTUÁRIO DO RIO ARACATIAÇU/CE
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
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
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
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
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
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
We obtain the quasinormal modes for tensor perturbations of Gauss-Bonnet (GB)
black holes in dimensions and vector perturbations in
and 8 dimensions using third order WKB formalism. The tensor perturbation for
black holes in 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 () increases. The imaginary part first
decreases upto a certain value of and then increases with
for both tensor and vector perturbations. For larger values of , the
QN frequencies for vector perturbation differs slightly from the QN frequencies
for tensorial one. It has also been shown that as , 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
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
expansion to be driven generically first order by fluctuations. However, within
a one--loop calculation directly in 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
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
- …