On the Bound States in a Non-linear Quantum Field Theory of a Spinor Field with Higher Derivatives

We consider a model of quantum field theory with higher derivatives for a spinor field with quartic selfinteraction. With the help of the Bethe-Salpeter equation we study the problem of the two particle bound states in the "chain" approximation. The existence of a scalar bound state is established.Comment: 14 pages, no figures, LaTe

Getting Information on the WWW for Educational Purposes: Problems and a Possible Solution

One of the great advantages of the World Wide Web (WWW) is the enormous amount of information it makes available. Nevertheless, URL (Universal Resource Locator) addresses obtained from search engines often have little to do with what users are actually interested in finding. This proves especially problematic when one is searching for educational material. In order to improve on this situation we have designed a search engine that specialises in managing content previously selected from the Internet. The search engine is compatible with both keywords and keyphrases.One of the great advantages of the World Wide Web (WWW) is the enormous amount of information it makes available. Nevertheless, URL (Universal Resource Locator) addresses obtained from search engines often have little to do with what users are actually interested in finding. This proves especially problematic when one is searching for educational material. In order to improve on this situation we have designed a search engine that specialises in managing content previously selected from the Internet. The search engine is compatible with both keywords and keyphrases

The novel chemokine receptor CXCR7 regulates trans-endothelial migration of cancer cells

<p>Abstract</p> <p>Background</p> <p>Migration of metastatic tumor cells from the bloodstream into lymph nodes is thought to be facilitated by expression of the chemokine receptors CCR7, CXCR4 and, for B cell-derived tumors, CXCR5. Expression of their respective chemokine ligands (CCL19, CCL21, CXCL12 and CXCL13) by endothelial cells inside the lymph nodes facilitates the trans-endothelial migration (TEM) of these cells through high endothelial venules into the lymph node parenchyma. It is known that CXCR7, a second CXCL12 receptor, regulates TEM of CXCR4+CXCR7+ tumor cells towards a CXCL12 source. In this study, we set out to assess the potential stimulation by CXCL12 of tumor cell TEM towards other chemokines and whether CXCR7 might be able to regulate such effects.</p> <p>Methods</p> <p>The human Burkitt's lymphoma cell line NC-37, which expresses CXCR4, CXCR5, CXCR7 and CCR7, was selected as a model system. TEM of these cells through a human HUVEC endothelial cell monolayer was used as the main model system for these studies. Regulation of their TEM behavior by various concentrations of the various cognate chemokines for the above-mentioned receptors, placed in either the source or target wells of modified Boyden chamber migration plates, was assessed by quantifying the number of cells migrated under each experimental condition.</p> <p>Results</p> <p>Exposure of CXCR4⁺CXCR7⁺cancer cells to CXCL12 greatly potentiated their TEM towards the chemokines CCL19 and CXCL13. This CXCL12-potentiated TEM was inhibited by the second CXCR7 chemokine ligand, CXCL11, as well as CXCR7-specific small molecule antagonists and antibodies. In contrast, the CXCR4 antagonist AMD3100 was less effective at inhibiting CXCL12-potentiated TEM. Thus, CXCR7 antagonists may be effective therapeutic agents for blocking CXCL12-mediated migration of CXCR4⁺CXCR7⁺tumor cells into lymph nodes, regardless of whether the cancer cells follow a CXCL12 gradient or whether serum CXCL12 stimulates their migration towards CCR7 and CXCR5 chemokines in the lymph nodes.</p

Evolución del Fitoplancton tóxico en las costas andaluzas durante el periodo 2003-2006

[ESP] En el presente estudio se describen las principales floraciones tóxicas de los últimos cuatro años y los parámetros oceanográficos que las acompañan. Las especies que con mayor frecuencia desencadenan episodios tóxicos en el litoral andaluz siguen siendo los dinoflagelados Dinophysis acuminata y Gymnodinium catenatum, así como algunas especies del género Pseudo-nitzschia. Como es habitual, Dinophysis acuminata desarrolla en la costa atlántica (Huelva) proliferaciones recurrentes en primavera y en verano asociadas a la presencia de toxicidad en el molusco. En el litoral mediterráneo, las concentraciones de esta especie son normalmente muy inferiores a las del litoral atlántico y no muestran un claro patrón estacional, pero es relevante por su magnitud un episodio ocurrido en Agosto de 2003 en la costa oriental de Málaga, el mayor en los últimos cuatro años, que causó intoxicaciones a un colectivo de más de 20 personas por consumir mejillón de roca, según informaron las autoridades sanitarias de la zona. El dinoflagelado Gymnodinium catenatum es la especie de mayor incidencia en la costa mediterránea; destaca por un lado su alta frecuencia de aparición durante el año 2003 y su ausencia en el año 2005. Las especies del género Pseudo-nitzschia se observan durante todo el periodo de estudio, si bien la presencia de ácido domoico en moluscos se ha visto asociada únicamente a proliferaciones de Pseudo-nitzschia australis. Otra especie de interés por sus efectos nocivos (producción de mucílago) es el dinoflagelado Gonyaulax hyalina, cuyas mayores proliferaciones se detectan en el Mediterráneo

Review of some classical gravitational superenergy tensors using computational techniques

We use computational algorithms recently developed by us to study completely four index divergence free quadratic in Riemann tensor polynomials in GR. Some results are new and some other reproduce and/or correct known ones. The algorithms are part of a Mathematica package called Tools of Tensor Calculus (TTC)[web address: http://baldufa.upc.es/ttc

Improved electrocatalytic activity of Pt on carbon nanofibers for glucose oxidation mediated by support oxygen groups in Pt perimeter

Support effects in supported metal catalysts are well studied for thermocatalytic reactions, but less studied for electrocatalytic reactions. Here, we prepared a series of Pt supported on carbon nanofiber catalysts which vary in their Pt particle size and the content of oxygen groups on the surface of the CNF. We show that the activity of these catalysts for electrocatalytic glucose oxidation relates linearly with the content of support oxygen groups. Since the electronic state of Pt (XAS) and Pt surface structure (CO-stripping) were indistinguishable for all materials, we conclude that sorption effects of glucose play a crucial role in catalytic activity. This was further confirmed by establishing a relation between the annulus of the Pt particles and the activit

Semiclassical Equations for Weakly Inhomogeneous Cosmologies

The in-in effective action formalism is used to derive the semiclassical correction to Einstein's equations due to a massless scalar quantum field conformally coupled to small gravitational perturbations in spatially flat cosmological models. The vacuum expectation value of the stress tensor of the quantum field is directly derived from the renormalized in-in effective action. The usual in-out effective action is also discussed and it is used to compute the probability of particle creation. As one application, the stress tensor of a scalar field around a static cosmic string is derived and the backreaction effect on the gravitational field of the string is discussed.Comment: 35 pages, UAB-FT 316, Latex (uses a4wide.sty, a4.sty included in the file)(replaced due to tex problems

Root density and accumulation of Myrobalan plum tree grafted with Methley Japanese plum

Ra Objective: to determine the root phenology of Myrobalan plum tree grafted with Methley Japanese plum. Materials and methods: a quota sampling was used to select five trees from the experimental orchard. Within the volume of soil adjacent to tree´s roots, 330 cm3 of soil were sampled and collected each month, in order to identify root type, quantify their fresh and dry weight, and carry out statistical analyses. Results:The highest densities of growing and absorbing roots were observed at 0-25 cm soil depth during the phenological cycle. A higher density of intermediate and conducting roots was recorded at 25-50 cm soil depth, just at the beginning of the ecodormancy. Conclusions: the highest root accumulation was recorded when moisture and soil temperature were not optimal but the cultivar did not record a significant vegetative and reproductive growth

Health care and societal costs of the management of children and adolescents with attention-deficit/hyperactivity disorder in Spain: a descriptive analysis.

Background: Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition in childhood (5.3% to 7.1% worldwide prevalence), with substantial overall financial burden to children/adolescents, their families, and society. The aims of this study were to describe the clinical characteristics of children and adolescents with ADHD in Spain, estimate the associated direct/indirect costs of the disorder, and assess whether the characteristics and financial costs differed between children/adolescents adequately responding to currently available pharmacotherapies compared with children/adolescents for whom pharmacotherapies failed. Methods: This was a multicenter, cross-sectional, descriptive analysis conducted in 15 health units representative of the overall Spanish population. Data on demographic characteristics, socio-occupational status, social relationships, clinical variables of the disease, and pharmacological and non-pharmacological treatments received were collected in 321 children and adolescents with ADHD. Direct and indirect costs were estimated over one year from both a health care system and a societal perspective. Results: The estimated average cost of ADHD per year per child/adolescent was ¿5733 in 2012 prices; direct costs accounted for 60.2% of the total costs (¿3450). Support from a psychologist/educational psychologist represented 45.2% of direct costs and 27.2% of total costs. Pharmacotherapy accounted for 25.8% of direct costs and 15.5% of total costs. Among indirect costs (¿2283), 65.2% was due to caregiver expenses. The total annual costs were significantly higher for children/adolescents who responded poorly to pharmacological treatment (¿7654 versus ¿5517; P = 0.024), the difference being mainly due to significantly higher direct costs, particularly with larger expenses for non-pharmacological treatment (P = 0.012). Conclusions: ADHD has a significant personal, familial, and financial impact on the Spanish health system and society. Successful pharmacological intervention was associated with lower overall expenses in the management of the disorder

On Imprimitive Representations of Finite Reductive Groups in Non-defining Characteristic

In this paper, we begin with the classification of Harish-Chandra imprimitive representations in non-defining characteristic. We recall the connection of this problem to certain generalizations of Iwahori-Hecke algebras and show that Harish-Chandra induction is compatible with the Morita equivalence by Bonnaf\'{e} and Rouquier, thus reducing the classification problem to quasi-isolated blocks. Afterwards, we consider imprimitivity of unipotent representations of certain classical groups. In the case of general linear and unitary groups, our reduction methods then lead to results for arbitrary Lusztig series