Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U) in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR) and two Pebble-Bed Accelerator Driven Systems (ADSs) was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.Received: 09 February 2015; Revised: 12 May 2015; Accepted: 20 May 201

Interaction of Variable Bacterial Outer Membrane Lipoproteins with Brain Endothelium

Previously we reported that the variable outer membrane lipoprotein Vsp1 from the relapsing fever spirochete Borrelia turicatae disseminates from blood to brain better than the closely related Vsp2 [1]. Here we studied the interaction between Vsp1 and Vsp2 with brain endothelium in more detail.We compared Vsp1 to Vsp2 using human brain microvascular endothelial cell (HBMEC) association assays with aminoacid radiolabeled Vsp-expressing clones of recombinant Borrelia burgdorferi and lanthanide-labeled purified lipidated Vsp1 (LVsp1) and Vsp2 (LVsp2) and inoculations of the lanthanide-labeled proteins into mice. The results showed that heterologous expression of LVsp1 or LVsp2 in B. burgdorferi increased its association with HBMEC to a similar degree. Purified lanthanide-labeled lipidated Vsp1 (LVsp1) and LVsp2 by themselves were capable of associating with HBMEC. The association of LVsp1 with brain endothelium was time-dependent, saturable, and required the lipidation. The association of Vsp1 with HBMEC was inhibited by incubation at lower temperature or with excess unlabeled LVsp1 or LVsp2 but not with excess rVsp1 or mouse albumin or an anti Vsp1 monoclonal antibody. The association of LVsp2 with HBMEC and its movement from blood to brain parenchyma significantly increased in the presence of LVsp1.Variable bacterial outer membrane lipoproteins interact with brain endothelium differently; the lipidation and variable features at the protein dome region are key modulators of this interaction

Propuesta de un procedimiento para la construcción y validación de un instrumento psicométrico con base en un cuestionario de conocimientos sobre enfermedad cardiovascular en farmacias comunitarias de España.

Introducción: En la práctica clínica se requiere de herramientas para valorar el conocimiento de los pacientes, siendo los cuestionarios uno de los instrumentos más comunes. En general, los cuestionarios o instrumentos que se utilizan son traducidos o, bien, realizados ad hoc, limitando así su fiabilidad y validez. Objetivo: Desarrollar una propuesta global con el procedimiento para diseñar y validar un cuestionario. Métodos: Se realizaron revisiones bibliográficas en Pubmed/Medline y en Google Scholar de artículos con los siguientes términos: validation questionnaire and desing, developing a questionnaire y validación, diseño y cuestionario, que permitan identificar los pasos y la metodología adecuada para el diseño y la validación de un cuestionario. Resultados: Mediante la revisión se identificaron 78 artículos y se accedió al texto completo de 75 artículos. Con la información obtenida se elaboró una propuesta para diseñar y validar cuestionarios de conocimiento por pacientes. Conclusiones: Se presenta una propuesta de diseño y validación de cuestionario para orientar trabajos con este fin, la cual debe ser validada en futuros estudios

Propuesta de un procedimiento para la construcción y validación de un instrumento psicométrico con base en un cuestionario de conocimientos sobre enfermedad cardiovascular en farmacias comunitarias de España.

Introducción: En la práctica clínica se requiere de herramientas para valorar el conocimiento de los pacientes, siendo los cuestionarios uno de los instrumentos más comunes. En general, los cuestionarios o instrumentos que se utilizan son traducidos o, bien, realizados ad hoc, limitando así su fiabilidad y validez. Objetivo: Desarrollar una propuesta global con el procedimiento para diseñar y validar un cuestionario. Métodos: Se realizaron revisiones bibliográficas en Pubmed/Medline y en Google Scholar de artículos con los siguientes términos: validation questionnaire and desing, developing a questionnaire y validación, diseño y cuestionario, que permitan identificar los pasos y la metodología adecuada para el diseño y la validación de un cuestionario. Resultados: Mediante la revisión se identificaron 78 artículos y se accedió al texto completo de 75 artículos. Con la información obtenida se elaboró una propuesta para diseñar y validar cuestionarios de conocimiento por pacientes. Conclusiones: Se presenta una propuesta de diseño y validación de cuestionario para orientar trabajos con este fin, la cual debe ser validada en futuros estudios

Mirror Symmetry, Mirror Map and Applications to Calabi-Yau Hypersurfaces

Mirror Symmetry, Picard-Fuchs equations and instanton corrected Yukawa couplings are discussed within the framework of toric geometry. It allows to establish mirror symmetry of Calabi-Yau spaces for which the mirror manifold had been unavailable in previous constructions. Mirror maps and Yukawa couplings are explicitly given for several examples with two and three moduli.Comment: 59 pages. Some changes in the references, a few minor points have been clarifie

Recent Efforts in the Computation of String Couplings:

We review recent advances towards the computation of string couplings. Duality symmetry, mirror symmetry, Picard-Fuchs equations, etc. are some of the tools.Comment: Talk hold at the `International Conference on Modern Problems in Quantum Field Theorie, Strings and Quantum Gravity', Kiev, June 1992, 18 page

Turbulence in the Solar Atmosphere: Manifestations and Diagnostics via Solar Image Processing

Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of solar magnetic fields. While these techniques advance our understanding of the physical system at work, it is unclear whether they can be used to predict solar eruptions, thus obtaining a practical significance for space weather. We address part of this problem by focusing on solar active regions and by investigating the usefulness of scaling and multi-scaling image-processing techniques in solar flare prediction. Since solar flares exhibit spatial and temporal intermittency, we suggest that they are the products of instabilities subject to a critical threshold in a turbulent magnetic configuration. The identification of this threshold in scaling and multi-scaling spectra would then contribute meaningfully to the prediction of solar flares. We find that the fractal dimension of solar magnetic fields and their multi-fractal spectrum of generalized correlation dimensions do not have significant predictive ability. The respective multi-fractal structure functions and their inertial-range scaling exponents, however, probably provide some statistical distinguishing features between flaring and non-flaring active regions. More importantly, the temporal evolution of the above scaling exponents in flaring active regions probably shows a distinct behavior starting a few hours prior to a flare and therefore this temporal behavior may be practically useful in flare prediction. The results of this study need to be validated by more comprehensive works over a large number of solar active regions.Comment: 26 pages, 7 figure