Estudio de la electro-filtración a presión constante de suspensiones sólido-líquido

Debido a que los sistemas de filtración utilizados actualmentesólo pueden eliminar una parte del agua contenida en la suspensión, se han realizado investigaciones con elobjetivo de obtener mayores rendimientos en la filtraciónmediante la aplicación de un campo eléctrico en un filtro presión. Para ello, se han llevado a cabo electro-filtracionesaplicando una diferencia de presión constante de0.4 bar y diferentes valores de intensidad eléctrica (de 0 a2.21 A). Se ha estudiado la influencia del campo eléctricosobre el contenido en agua de la torta, la presión electroosmótica, a resistencia específica de la torta y el pH delfiltrado y del agua retenida en la torta. Se ha analizado elefecto de la electroforesis y de la electro-ósmosis sobreestas propiedades. El estudio de la variación del pH determinaque la operación unitaria de electro-filtración sóloes aplicable en los procesos donde el sólido obtenido seaun residuo o cuyas propiedades puedan ser modificadas.Por fin, se ha definido un nuevo parámetro que tiene encuenta la compresibilidad de la torta según la intensidadeléctrica aplicada y ha convenido en denominarse factorde electro-compresibilidad

Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems

A PL spherical harmonics-nodal collocation method is applied to the solution of the multidimensional neutron source transport equation. Vacuum boundary conditions are approximated by setting Marshak's conditions. The method is applied to several 1D, 2D and 3D problems with isotropic fixed source and with isotropic and anisotropic scattering. These problems are chosen to test this method in limit conditions, showing that in some cases a high order $P_L$ approximation is required to obtain accurate results and convergence. Results are also compared with the ones provided by several reference codes showing good agreement. It is also shown that Marshak's approximation to vacuum boundary conditions gives the same results that simulating vacuum with a purely absorbing medium and setting zero flux boundary conditions.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE2011-22823, and the Generalitat Valenciana under project PROMETEO11/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2016). Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems. Annals of Nuclear Energy. 87:89-100. https://doi.org/10.1016/j.anucene.2015.07.040S891008

A study of the radiative transfer equation using a spherical harmonics-nodal collocation method

[EN] Optical tomography has found many medical applications that need to know how the photons interact with the different tissues. The majority of the photon transport simulations are done using the diffusion approximation, but this approximation has a limited validity when optical properties of the different tissues present large gradients, when structures near the photons source are studied or when anisotropic scattering has to be taken into account. As an alternative to the diffusion model, the PL equations for the radiative transfer problem are studied. These equations are discretized in a rectangular mesh using a nodal collocation method. The performance of this model is studied by solving different 1D and 2D benchmark problems of light propagation in tissue having media with isotropic and anisotropic scattering.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE-2014-59442-P and by the Generalitat Valenciana under project PRO-METE II/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2017). A study of the radiative transfer equation using a spherical harmonics-nodal collocation method. Journal of Quantitative Spectroscopy and Radiative Transfer. 189:25-36. https://doi.org/10.1016/j.jqsrt.2016.11.008S253618

The neurobiological foundations of learning disabilities

Learning disabilities constitute a heterogeneous group of disorders that involve significant alterations in different cognitive domains (acquisition and use of language, reasoning, mathematical skills, visuospatial abilities, and so forth) that are not accounted for by a low level of intelligence, inadequate sociocultural development or lack of academic opportunities. They result from an alteration in basic psychological processes, developmentally linked to an alteration in the central nervous system. Current functional neuroimaging techniques have made it possible to develop a new type of approach to the neurofunctional foundations underlying these disorders, especially with regard to difficulties in the realm of reading/writing (developmental dyslexia) and attention deficit hyperactivity disorder (ADHD), which have their highest incidence among the infantile population of school-age children. Development. Neuroimaging studies have revealed a pattern of atypical activity in both kinds of disorders. In the case of dyslexia, alterations have been observed in the perisylvian circuits that underlie the mechanisms involved in reading skills. Studies into ADHD suggest a fronto-striatal dysfunction linked to the difficulties encountered to achieve inhibitory control, as well as alterations in the inferior parietal and posterior temporal cortex. Conclusions. Functional neuroimaging studies have shown that the clinical manifestations of these disorders are not only due to a dysfunction in specific areas of the brain, but also to alterations in the pattern of connectivityLas dificultades de aprendizaje comprenden un grupo heterogéneo de trastornos que implican alteraciones significativas en diferentes dominios cognitivos (adquisición y uso del lenguaje, razonamiento, habilidades matemáticas, visuoespaciales, etc.) no justificadas por bajo nivel intelectual, desarrollo sociocultural inadecuado o falta de oportunidades académicas. Éstas son el resultado de una alteración en los procesos psicológicos básicos, evolutivamente ligados a una alteración del sistema nervioso central. Las actuales técnicas de neuroimagen funcional han permitido un nuevo tipo de acercamiento a las bases neurofuncionales de estos trastornos, particularmente de las dificultades en el ámbito de la lectoescritura (dislexia evolutiva) y del trastorno por déficit de atención e hiperactividad (TDAH), los cuales tienen el mayor nivel de incidencia en la población escolar infantil. Desarrollo. Los estudios de neuroimagen han revelado un patrón de actividad atípico en ambos tipos de trastorno. En el caso de la dislexia, se han observado alteraciones de los circuitos perisilvianos que sustentan los mecanismos de lectura. Los estudios sobre TDAH sugieren una disfunción frontoestriatal ligada a las dificultades para el control inhibitorio, así como alteraciones en la corteza temporal posterior y parietal inferior. Conclusiones. Los estudios de neuroimagen funcional revelan que las manifestaciones clínicas de estos trastornos no se deben sólo a la disfunción de áreas cerebrales concretas, sino también a alteraciones en el patrón de conectividadAs dificuldades de aprendizagem compreendem um grupo heterogéneo de perturbações que implicam alterações significativas em diferentes domínios cognitivos (aquisição e uso da linguagem, raciocínio, habilidades matemáticas, visuo-espaciais, etc.) não justificadas por baixo nível intelectual, desenvolvimento sócio-cultural inadequado ou falta de oportunidades académicas. Estas são o resultado de uma alteração nos processos psicológicos básicos, evolutivamente ligados a uma alteração do sistema nervoso central. As técnicas actuais de neuroimagem funcional permitiram um novo tipo de abordagem às bases neuro-funcionais destas perturbações, particularmente das dificuldades no âmbito da leitura e da escrita (dislexia evolutiva) e da perturbação por défice de atenção e hiperactividade (PDAH), as quais têm o maior nível de incidência na população escolar infantil. Desenvolvimento. Os estudos das neuroimagens revelaram um padrão de actividade atípico em ambos os tipos de perturbação. No caso da dislexia, foram observadas alterações dos circuitos perisilvícos que sustentam os mecanismos de leitura. Os estudos sobre o PDAH sugerem uma disfunção fronto-estriatal ligada às dificuldades no controlo inibitório, assim como alterações no córtex temporal posterior e parietal inferior. Conclusões. Os estudos de neuroimagem funcional revelam que as manifestações clínicas destas perturbações não se devem apenas à disfunção de áreas cerebrais concretas, como também a alterações no padrão de conectividad

Genetic analyses of celiac disease in a Spanish population confirm association with CELIAC3 but not with CELIAC4

[EN] Genetic predisposition to celiac disease (CD) is determined primarily by the human leukocyte antigen (HLA) genes (CELIAC1 region; 6p21), although many loci are involved in disease susceptibility. First, we have analysed a large series of CD patients from the Spanish Mediterranean region who had previously been characterised for the HLA complex. We have investigated how relevant regions contribute to CD susceptibility: CELIAC3 (CD28/CTLA4/ICOS region on 2q33) and CELIAC4 (19p13) as well as the tumour necrosis factor alpha (TNF-alpha) and the linfotoxin loci by case-control and association analyses. We highlight the association with the +49*A allele of cytotoxic T-lymphocyte-associated antigen 4 locus (P = 0.01), and the -308*A of TNF-alpha locus (P = 0.0008) in DQ2 individuals, although an independent role for TNF-alpha as risk factor has not been proven. Moreover, we do not confirm the association with the CELIAC4 region polymorphisms described in other populations.We are grateful for the kind collaboration of patients and families and Asociación de Celíacos de la Comunidad Valenciana (ACECOVA). This work was supported by the Fondo de Investigacio¿n Sanitaria (grant PI02573) and by the CSIC Intramural Frontiers Project (PROFICEL). ED holds a fellowship from the Fundacio¿n La Fe. English text revised by F. BarracloughCapilla, A.; Donat, E.; Planelles, D.; Espinós-Armero, CÁ.; Ribes-Koninckx, C.; Palau, F. (2007). Genetic analyses of celiac disease in a Spanish population confirm association with CELIAC3 but not with CELIAC4. Tissue Antigens. 70(4):324-329. https://doi.org/10.1111/j.1399-0039.2007.00899.x32432970

No-core shell model for 48-Ca, 48-Sc and 48-Ti

We report the first no-core shell model results for $^{48}Ca$, $^{48}Sc$ and $^{48}Ti$ with derived and modified two-body Hamiltonians. We use an oscillator basis with a limited $\hbar\Omega$ range around $45/A^{1/3}-25/A^{2/3} = 10.5 MeV$ and a limited model space up to $1\hbar\Omega$. No single-particle energies are used. We find that the charge dependence of the bulk binding energy of eight A=48 nuclei is reasonably described with an effective Hamiltonian derived from the CD-Bonn interaction while there is an overall underbinding by about 0.4 MeV/nucleon. However, the resulting spectra exhibit deficiencies that are anticipated due to: (1) basis space limitations and/or the absence of effective many-body interactions; and, (2) the absence of genuine three-nucleon interactions. We then introduce additive isospin-dependent central terms plus a tensor force to our Hamiltonian and achieve accurate binding energies and reasonable spectra for all three nuclei. The resulting no-core shell model opens a path for applications to the double-beta ($\beta\beta$) decay process.Comment: Revised content and added reference

Searches for neutrinoless double beta decay

Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of $^{136}$Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

Searches for neutrinoless double beta decay

Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of $^{136}$Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

Searches for neutrinoless double beta decay

Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of $^{136}$Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

Sterol Biosynthesis and Azole Tolerance Is Governed by the Opposing Actions of SrbA and the CCAAT Binding Complex

Azole drugs selectively target fungal sterol biosynthesis and are critical to our antifungal therapeutic arsenal. However, resistance to this class of drugs, particularly in the major human mould pathogen Aspergillus fumigatus, is emerging and reaching levels that have prompted some to suggest that there is a realistic probability that they will be lost for clinical use. The dominating class of pan-azole resistant isolates is characterized by the presence of a tandem repeat of at least 34 bases (TR34) within the promoter of cyp51A, the gene encoding the azole drug target sterol C14-demethylase. Here we demonstrate that the repeat sequence in TR34 is bound by both the sterol regulatory element binding protein (SREBP) SrbA, and the CCAAT binding complex (CBC). We show that the CBC acts complementary to SrbA as a negative regulator of ergosterol biosynthesis and show that lack of CBC activity results in increased sterol levels via transcriptional derepression of multiple ergosterol biosynthetic genes including those coding for HMG-CoA-synthase, HMG-CoA-reductase and sterol C14-demethylase. In agreement with these findings, inactivation of the CBC increased tolerance to different classes of drugs targeting ergosterol biosynthesis including the azoles, allylamines (terbinafine) and statins (simvastatin). We reveal that a clinically relevant mutation in HapE (P88L) significantly impairs the binding affinity of the CBC to its target site. We identify that the mechanism underpinning TR34 driven overexpression of cyp51A results from duplication of SrbA but not CBC binding sites and show that deletion of the 34 mer results in lack of cyp51A expression and increased azole susceptibility similar to a cyp51A null mutant. Finally we show that strains lacking a functional CBC are severely attenuated for pathogenicity in a pulmonary and systemic model of aspergillosis