10,520 research outputs found
Slepton Non-Universality in the Flavor-Effective MSSM
Supersymmetric theories supplemented by an underlying flavor-symmetry
provide a rich playground for model building aimed at
explaining the flavor structure of the Standard Model. In the case where
supersymmetry breaking is mediated by gravity, the soft-breaking Lagrangian
typically exhibits large tree-level flavor violating effects, even if it stems
from an ultraviolet flavor-conserving origin. Building on previous work, we
continue our phenomenological analysis of these models with a particular
emphasis on leptonic flavor observables. We consider three representative
models which aim to explain the flavor structure of the lepton sector, with
symmetry groups , and .Comment: References added, minor typos corrected. 28 pages, 8 figure
La Corona de Aragón y el Norte de Africa: las diferentes áreas de intervención mercantil catalano-aragonesa en el Magreb a finales del siglo XIV y principios del XV
El comercio exterior bajomedieval de la Corona de Aragón, desde una óptica general, ha sido analizado con excesiva frecuencia en base a una única perspectiva: Barcelona. Si bien es innegable la importancia del centro barcelonés en la expansión comercial catalano-aragonesa, generalmente se olvida que la presencia mercantil de la Corona de Aragón en las diferentes plazas, tanto mediterráneas como atlánticas, estaba asegurada no sólo por operadores procedentes de Barcelona, sino también por valencianos, mallorquines, zaragozanos, perpiñaneses o tortosinos, entre otros. En este sentido, es acertada la puntualización de P. Vilar al relacionar a la Barcelona del trescientos, dotada de una población que no llegaba a los 40.000 habitantes, con ciudades como Bolonia, Padua, Palermo, Nápoles, Londres, Praga o Bruselas, y no con los grandes emporios comerciales de la época como Génova, Venecia, Florencia o Brujas, cuya envergadura urbana era mucho más notable. Si Barcelona ejerció un papel importante en el ámbito del comercio internacional fue debido no tanto a su actuación individual, sino al hecho de formar parte integrante de una red más amplia que abarcaba cenmos como Palma de Mallorca, Valencia, Perpiñán y otros de menor entidad; una red que propiciaba una complementariedad en lugar de una rivalidad entre los diferentes tráficos
Flow Blurring-Enabled Production of Polymer Filaments from Poly(ethylene oxide) Solutions
Flow blurring (FB) atomizers are relatively
simple yet robust devices used for the generation of sprays
from solutions of a wide range of viscosities. In this work, we
have demonstrated that FB devices may also be applied for
massive production of liquid filaments from polymeric
solutions. They can later be transformed into solid filaments
and fibers, leading to the production of so-called fiber mats.
The liquid precursors consisted of poly(ethylene oxide)
(PEO) solutions of varying molecular weights (105 [100k]
to 4 × 106 g/mol [4M]) and concentrations. The FB device
was operated in the gas pressure range of 3−6 bar. Except for
solutions of PEO 100k, all solutions exhibited a shear thinning
behavior. For massive filament production, a threshold
polymer concentration (ct) was identified for each molecular
weight. Below such concentration, the atomization resulted in droplets (the classical FB functioning mode). Such a threshold
value decreased as the PEO molecular weight increased, and it coincides with the polymer coil overlap concentration, c*. The
viscoelastic nature of the solutions was also observed to increase with the molecular weight. A 3.2 dependency of the zero-shear
rate viscosity on a so-called Bueche parameter was found for filament production, whereas a nearly linear dependency was found
for droplet production. In general, the mean diameter of the filaments decreased as they traveled downstream from the
atomization point. Furthermore, at a given distance from the atomizer outlet and gas pressure, the mean filament diameter
slightly shifted toward larger sizes with increasing PEO molecular weight. The tendency agrees well with the calculated
filaments’ Deborah number, which increases with PEO molecular weight. The approach presented herein describes a highthroughput
and efficient method for the massive production of viscous filaments. These may be transformed into fibers by an
on-line drying step.Ministerio de Economía y Competitividad DPI2016-78887-C3-1-
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Self-assembly of Fmoc-tetrapeptides based on the RGDS cell adhesion motif
Self-assembly in aqueous solution has been investigated for two Fmoc [Fmoc ¼ N-(fluorenyl)-9-methoxycarbonyl] tetrapeptides comprising the RGDS cell adhesion motif from fibronectin or the scrambled sequence GRDS. The hydrophobic Fmoc unit confers amphiphilicity on the molecules, and
introduces aromatic stacking interactions. Circular dichroism and FTIR spectroscopy show that the self-assembly of both peptides at low concentration is dominated by interactions among Fmoc units, although Fmoc-GRDS shows b-sheet features, at lower concentration than Fmoc-RGDS. Fibre X-ray diffraction indicates b-sheet formation by both peptides at sufficiently high concentration. Strong
alignment effects are revealed by linear dichroism experiments for Fmoc-GRDS. Cryo-TEM and smallangle
X-ray scattering (SAXS) reveal that both samples form fibrils with a diameter of approximately 10 nm. Both Fmoc-tetrapeptides form self-supporting hydrogels at sufficiently high concentration. Dynamic shear rheometry enabled measurements of the moduli for the Fmoc-GRDS hydrogel, however syneresis was observed for the Fmoc-RGDS hydrogel which was significantly less stable to shear. Molecular dynamics computer simulations were carried out considering parallel and antiparallel b-sheet configurations of systems containing 7 and 21 molecules of Fmoc-RGDS or Fmoc-GRDS, the results being analyzed in terms of both intermolecular structural parameters and energy contributions
The Dark Side of the Self-Determination Theory and Its Influence on the Emotional and Cognitive Processes of Students in Physical Education
Amongst the main objectives of physical education (PE) classes is the consolidation of healthy lifestyle habits in young people and adolescents. Nonetheless, these classes can also provide the basis from which adverse experiences are generated which affect students’ perceptions of these classes. Previously conducted studies have focused on motivational processes and not on emotional processes, nor on the way in which students learn. The objective of the present study was to explore the dark side of the self-determination theory, its influence on emotional intelligence and the meta-cognitive strategies of students. Methodology: A total of 1602 young people undertaking secondary education participated, with self-reported ages between 13 and 19 years. The following questionnaires were utilized: Controlling Coach Behaviors Scale, Frustration of Psychological Needs in PE classes Scale, Emotional Intelligence in PE Scale and Motivated Strategies for Learning Questionnaire. A structural equation model was developed which explained causal associations between the study variables. Results: Psychological control positively predicted each one of the sub-factors of frustration of psychological needs. Frustration of psychological needs negatively predicted emotional intelligence. Finally, emotional intelligence positively predicted meta-cognitive thinking. Conclusions: The influence and importance of the teaching style adopted by teachers is indicated, in addition to the effect of students’ psychological experiences on emotions and learning strategie
Development of organic fertilizers from food market waste and urban gardening by composting in Ecuador
Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities. Concretely, in the Chimborazo Region (Ecuador), more than 80% of municipal solid waste is dumped into environment due to the lack of an efficient waste management strategy. Therefore, the aim of this study was to develop a demonstration project at field scale in this region to evaluate the feasibility of implanting the composting technology not only for the management of the organic waste fluxes from food market and gardening activities to be scaled-up in other developing regions, but also to obtain an end-product with a commercial value as organic fertilizer. Three co-composting mixtures were prepared using market wastes mixed with pruning of trees and ornamental palms as bulking agents. Two piles were created using different proportions of market waste and prunings of trees and ornamental palms: pile 1 (50:33:17) with a C/N ratio 25; pile 2: (60:30:10) with C/N ratio 24 and pile 3 (75:0:25) with C/N ratio 33), prepared with market waste and prunings of ornamental palm. Throughout the process, the temperature of the mixtures was monitored and organic matter evolution was determined using thermogravimetric and chemical techniques. Additionally, physico-chemical, chemical and agronomic parameters were determined to evaluate compost quality. The results obtained indicated that all the piles showed a suitable development of the composting process, with a significant organic matter decomposition, reached in a shorter period of time in pile 3. At the end of the process, all the composts showed absence of phytotoxicity and suitable agronomic properties for their use as organic fertilizers. This reflects the viability of the proposed alternative to be scaled-up in developing areas, not only to manage and recycle urban waste fluxes, but also to obtain organic fertilizers, including added value in economic terms related to nutrient contents.Peer ReviewedPostprint (published version
Lupus eritematoso sistémico en un gato
Describimos el caso clínico de un gato macho de dos años de edad con un historial de gingivoestomatitis ulcerativa. Los análisis realizados revelan fallo renal con proteinuria, trombocitopenia e hipoalbuminemia. Tras el diagnóstico diferencial de glomerulonefropatía se procede a realizar un análisis de anticuerpos antinucleares, obteniéndose un resultado positivo. Se realiza el diagnóstico de lupus eritematoso sistémico basándonos en la presencia de cuatro de los criterios establecidos por la Asociación Americana de Reumatismo para el diagnóstico de lupus en humanos
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