Decay rates for solutions of semilinear wave equations with a memory condition at the boundary

In this paper, we study the stability of solutions for semilinear wave equations whoseboundary condition includes a integral that represents the memory effect. We show that the dissipation is strong enough to produce exponential decay of the solution, provided the relaxation function also decays exponentially. When the relaxation function decays polinomially, we show that the solution decays polynomially and with the same rate

Global solutions and exponential decay for a nonlinear coupled system of beam equations of Kirchhoff type with memory in a domain with moving boundary

In this paper we prove the exponential decay in the case $n>2$, as time goes to infinity, of regular solutions for a nonlinear coupled system of beam equations of Kirchhoff type with memory and weak damping \begin{eqnarray*} &&u_{tt}+\Delta^2 u-M(||\nabla u||^2_{L^2(\Omega_t)}+||\nabla v||^2_{L^2(\Omega_t)})\Delta u\\ &&+\int^{t}_{0}g_1(t-s)\Delta u(s)ds +\alpha u_{t}+h(u-v)=0 \quad \mbox{in} \quad \hat{Q},\\ &&v_{tt}+\Delta^2 v-M(||\nabla u||^2_{L^2(\Omega_t)}+||\nabla v||^2_{L^2(\Omega_t)})\Delta v \\ &&+\int^{t}_{0}g_2(t-s)\Delta v(s)ds + \alpha v_{t}-h(u-v)=0 \quad \mbox{in} \quad \hat{Q} \end{eqnarray*} in a non cylindrical domain of $\mathbb{R}^{n+1}$ $(n\ge1)$ under suitable hypothesis on the scalar functions $M$, $h$, $g_1$ and $g_2$, and where $\alpha$ is a positive constant. We show that such dissipation is strong enough to produce uniform rate of decay. Besides, the coupling is nonlinear which brings up some additional difficulties, which plays the problem interesting. We establish existence and uniqueness of regular solutions for any $n\ge 1$

Solvability for a nonlinear coupled system of Kirchhoff type for the beam equations with nonlocal boundary conditions

In this paper, we investigate a mathematical model for a nonlinear coupled system of Kirchhoff type of beam equations with nonlocal boundary conditions. We establish existence, regularity and uniqueness of strong solutions. Furthermore, we prove the uniform rate of exponential decay. The uniform rate of polynomial decay is considered

Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK‐cell subsets and its impact on the understanding of their tissue distribution and functional properties

Blood Cells Mol Dis. 2001 Jul-Aug;27(4):731-43. Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties. Lima M, Teixeira MA, Queirós ML, Leite M, Santos AH, Justiça B, Orfão A. Service of Clinical Hematology, Unit of Cytometry, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed. PMID: 11778657 [PubMed - indexed for MEDLINE

Virtualization of pliocene sites in the Huelva province: valuating the paleontological heritage in differentiate educative settings I

El patrimonio paleontológico del Plioceno de la provincia de Huelva es uno de los más importantes de España y referente europeo de moluscos de este período. Sin embargo, no existe un inventario de catalogación básica de los principales yacimientos ni de los principales grupos fósiles presentes, así como de su importancia como patrimonio natural. El presente trabajo pretende rellenar este notable vacío con una proyección tanto hacia materias preuniversitarias como universitarias, así como hacia posibles instituciones y corporaciones públicas susceptibles de utilizarlo en sus planes de ordenación. Por otro lado, se pretende que actúe como mecanismo de interconexión entre titulaciones con bajo número de alumnos de nuevo ingreso y los centros de Bachillerato, de forma que incentive una posible elección de estos Grados por los alumnos de las opciones científico-tecnológicas. También puede ser interesante para captar egresados hacia Másteres Oficiales en Patrimonio Histórico y Natural. En este sentido, se ha realizado un DVD documental sobre el patrimonio paleontológico del Plioceno de la provincia de Huelva, concretamente de las formaciones “Arenas de Huelva” y “Arenas de Bonares” desarrolladas en ambientes marinos someros y costeros durante la última etapa de evolución neógena de la cuenca. Este documental incluye una visión de conjunto de los principales yacimientos fósiles de esta edad, así como una explicación de la evolución paleogeográfica de nuestra provincia y los organismos que la han caracterizado en los últimos millones de años. Esta aportación es aplicable en el trabajo de campo de varios Grados y Posgrados universitarios y de fácil uso como material didáctico en diversas asignaturas de E.S.O. y Bachillerato. Este trabajo se ha realizado en el marco del proyecto de innovación docente (PID nº 10050) de la Universidad de Huelva.The paleontological heritage from the Neogene in the province of Huelva is one of the most important in Spain and it is considered a European reference site for the mollusk fossil record from this period. However, there are not basic inventories neither for the main sites nor the major fossil groups. Furthermore, no inventories exist about their natural heritage importance. This work aims to fill this significant gap for both pre-university and university levels, as well as to public institutions and corporations that may use it in their management plans. In addition, it is intended to act as an linking mechanism between university degrees with low number of first-year students and high school centres, in order to encourage a possible choice of these Bachelor’s degrees by scientific and technological students. It may also be interesting to catch the attention of graduates for Official Masters in Historical and Natural Heritage. In this sense, a DVD-documentary has been made about the paleontological heritage from the Pliocene in the province of Huelva, specifically from the “Arenas de Huelva” and “Arenas de Bonares” formations. These units were developed in shallow marine and coastal environments during the last stage of the Neogene evolution in the Guadalquivir Basin. This documental includes an overview of main marine fossil sites from this age and a brief explanation of the palaeogeographic evolution of the Huelva province during the last million of years. This contribution is useful for the fieldwork at Bachelor and Master Degree level and it is easy to use as teaching materials in different ESO (Obligatory Secondary Teaching) and High School subjects. This work has been support for an Innovation in Teaching Project (PID No. 10050) of the Huelva University

Effet de la nutrition minérale sur l'incidence des "lixas" Sphaerodothis torrendiella et Sphaerodothis acrocomiae chez le cocotier Cocos nucifera L.

Les observations ont été réalisées pendant deux ans dans l'essai de nutrition minérale installé en 1984 dans le "municipio de Santa Luzia do Itanhy" - Sergipe, Brésil - pour déterminer l'effet de N, P, K, Mg sur l'incidence chez le cocotier Cocos nucifera des "lixas" petite et grande causées respectivement par Sphaerodothis torrendiella et S. acrocomiae. Un dispositif factoriel 2 exp. 4 a été utilisé avec et sans apport des nutriments de référence. Les évaluations du développement végétatif et de l'incidence des maladies ont été faites en comptant le nombre de feuilles émises, celui de feuilles vivantes, la circonférence du collet (cm) et le nombre de stromas de champignons sur six folioles de la feuille 7 la première année et de la feuille 10 la deuxième année. Les résultats obtenus démontrent que les éléments phosphore et potassium produisent des effets sur le développement végétatif des plants. La présence de N et/ou de P a induit une incidence moindre des "lixas", bien que cet effet n'ait été significatif qu'avec N sur la grande incidence de la maladie la première année. On a également noté une plus grande incidence sur la maladie la première année en présence de K, contrairement aux informations sur l'effet de cet élément sur d'autres maladies foliaires du cocotie

Nonextensive Entropies derived from Form Invariance of Pseudoadditivity

The form invariance of pseudoadditivity is shown to determine the structure of nonextensive entropies. Nonextensive entropy is defined as the appropriate expectation value of nonextensive information content, similar to the definition of Shannon entropy. Information content in a nonextensive system is obtained uniquely from generalized axioms by replacing the usual additivity with pseudoadditivity. The satisfaction of the form invariance of the pseudoadditivity of nonextensive entropy and its information content is found to require the normalization of nonextensive entropies. The proposed principle requires the same normalization as that derived in [A.K. Rajagopal and S. Abe, Phys. Rev. Lett. {\bf 83}, 1711 (1999)], but is simpler and establishes a basis for the systematic definition of various entropies in nonextensive systems.Comment: 16 pages, accepted for publication in Physical Review

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

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