2,234 research outputs found
Light at the end of the tunnel?
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152506/1/jlb10513_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152506/2/jlb10513.pd
Three-Higgs-doublet model with symmetry
We worked out in detail the three-Higgs-doublet extension of the standard
model when the symmetry, which is imposed to solve the flavor problem, is
extended to the scalar sector. The three doublets may be related to the fermion
mass generation and, in particular, they may be the unique responsible for the
generation of the neutrino masses. If this is the case, the respective VEVs
have to be quite smaller than the electroweak scale if no fine tuning in the
Yukawa couplings is assumed. We consider here the mass spectra in the scalar
sector in three different situations. In one of them there are no light scalars
at all, but in the other ones a light or two massless scalars, at the tree
level, may survive. The later fields are safe, from the phenomenological point
of view, since it couples mainly with neutrinos and/or becomes enough massive
at the tree level if there exist trilinear interactions. Quantum effects may be
important too.Comment: 11 pages, no figures, new references adde
The mediating role of self-criticism, experiential avoidance and negative urgency on the relationship between ED-related symptoms and difficulties in emotion regulation
Objective: Difficulties in emotion regulation are thought to play a transdiagnostic role across eating disorders (ED). In the current study, we explored with a path analysis the mediating role of self-criticism, experiential avoidance and negative urgency on the relationship between ED-related symptoms and dimensions of difficulties in emotion regulation. Method: Participants were 103 female outpatients recruited at a Portuguese ED hospital unit, diagnosed with an ED, aged 14–60 years old (M = 28.0, SD = 10.5), body mass index (BMI) ranging from 11.72 to 39.44 (M = 20.1, SD = 5.4). Results: The path analysis resulted in a model with an adequate fit to the data (SRMR = 0.05; RMSEA = 0.07 [0.00, 0.12], PCLOSE = 0.269; TLI = 0.97; IFI = 0.99; GFI = 0.95). A final model in which the relationship between ED-related symptoms and dimensions of difficulties in emotion regulation was mediated by self-criticism, experiential avoidance and negative urgency, accounted for a variance of 71% for strategies, 57% for non-acceptance, 62% for impulses, 56% for goals and 20% for clarity. Conclusion: Results suggest that self-criticism, experiential avoidance and negative urgency, combined, are relevant in the relationship between ED-related symptoms and difficulties in emotion regulation. ED treatment and emotion regulation skills may be enhanced through the inclusion of specific components that target self-criticism, experiential avoidance and negative urgency, as they become prominent during the therapeutic process.FCT - Fundação para a Ciência e a Tecnologia(POCI‐01‐0145‐FEDER‐028145
Ethanol as a Subgroup of the UNIFAC Model in the Prediction of Liquid-Liquid Equilibrium in Food and Fuel Systems
Ethanol has been employed as a solvent in biodiesel production and vegetable oil refining since it is more economically attractive and less toxic than methanol and hexane. Furthermore, ethanol has demonstrated easy recovery, good selectivity, and distribution coefficient for free fatty acids (FFA), which is the primary target in the refining process since high acidity oil can lead to the formation of side products. As the knowledge of phase equilibrium behavior of fatty systems is essential to design and optimize the extraction of FFA, this chapter will present two new UNIFAC subgroups for ethanol: EtOH-B, focused on biodiesel production; and EtOH-D, focused on the deacidification process. Except for ethanol and water subgroups fitted in this study, all remaining UNIFAC parameters were taken from the literature. The new EtOH-B and EtOH-D parameters provide a considerably lower mean square error (1.20% and 0.87%) than the other works available in the literature. The results show that new ethanol subgroups and the developed methodology are valuable tools in predicting liquid-liquid phase equilibrium for ethyl biodiesel and vegetable oil deacidification systems considered, resulting in reduced computational calculations and a relatively small split with the complex dataset established by the UNIFAC-LL model
Floods and climate change: certainties and uncertainties on the road to adaptation
[ES] En la actualidad existe una gran incertidumbre de los efectos del cambio climático en la peligrosidad de las inundaciones. Estos caudales extremos dependen de las características de las cuencas y representan una respuesta local que, a menudo, no pueden interpretarse a partir de los modelos de clima. En la práctica, esta incertidumbre dificulta la adaptación a los riesgos futuros según el mandato de la Directiva Europea de Inundaciones (2007/60/EC). En un caso de estudio (Rambla de la Viuda, Castellón) se ha aplicado un análisis de caudales máximos (recurrencia de 100 años) en base a proyecciones de precipitación extrema (escenario RCP 8.5) realizadas con modelos de clima regionales (Eurocordex), y convertidos en caudal instantáneo mediante un modelo hidrológico distribuido (TETIS). El análisis muestra una elevada variabilidad en los resultados, siendo difícil determinar la bondad de los modelos de clima. Por otro lado se han analizado series largas de inundaciones obtenidas a partir de registros históricos y sedimentarios (paleoinundaciones), que permiten obtener los caudales máximos registrados secularmente. Esta información incorpora eventos de inundación que han ocurrido en periodos pasados de calentamiento relativo o de incremento de la actividad de las inundaciones, considerando que los eventos extremos que han acontecido alguna vez pueden repetirse en el futuro. Estos caudales del pasado se han analizado conjuntamente con registros instrumentales mejorando sustancialmente el cálculo de los cuantiles de inundación requeridos en los mapas de peligrosidad de la Directiva de Inundaciones. Los datos de extremos del paleocrecidas permiten validar los datos de los modelos de clima e hidrológicos para los cuantiles altos. Esta aproximación constituye una práctica beneficiosa (win-win actions), de relativo bajo costo, y que permite avanzar en la adaptación al cambio climático. Igualmente, esta información del pasado proporciona una evidencia¿ real¿ de sucesos de inundación que posibilitan la recuperación de la cultura del riesgo.[EN] There are major challenges in dealing with the effects of climate change on flood hazard worldwide. Discharge resulting from extreme rainfalls depend on catchment characteristics and commonly
represent a local response that cannot be interpreted entirely from climate models. In practice, this
uncertainty makes it difficult to adapt to future risks as mandated by the European Flood Directive
(2007/60/EC). In a case study (rambla de la Viuda, Castelló) an analysis of peak discharges (100-year
recurrence) has been applied based on extreme precipitation projections (RCP 8.5 scenario) made
with regional climate models (Eurocordex), and converted into instantaneous discharge using a distributed hydrological model (TETIS). The analysis shows a high variability in the results, making
difficult to determine the goodness of the climate models. On the other hand, long series of floods
obtained from historical and sedimentary records (paleofloods) have been analysed, obtaining centennial long records of flood discharges. This information incorporates flood events that have occurred
in past periods of relative warming or increased flood activity, considering that extreme events that
have occurred in the past may be repeated in the future. These past discharges have been analysed in
conjunction with instrumental records, substantially improving the calculation of the flood quantiles
required in the Flood Directive hazard maps. Paleoflood extreme data allow validation of climate and
hydrological model data for high quantiles. This approach is a win-win action, relatively low-cost, and allows progressing on the adaptation to climate change. Likewise, this information from the past
provides ¿real¿ evidence of flood events as a direct guide of flood possibilities, such that local people
are motivated to deal with their local flood problems increasing the risk culture.Este trabajo ha sido financiado por Fundación Biodiversidad (MITERD) a través del proyecto
Adaptapresa, y por el Ministerio de Ciencia e Innovación de España a través de los proyectos de
investigación EPHIMED (CGL2017-86839-C3-1-R), TETISCHANGE (RTI2018-093717-B-100) y
EPHIDREAMS (PID2020-116537RB-I00), cofinanciados de fondos europeos (FEDER). Agradecemos
la revisión y los comentarios realizados por tres revisores anónimos y el trabajo realizado por los editores
de la revista.Benito, G.; Beneyto, C.; Aranda Domingo, JÁ.; Machado, M.; Francés, F.; Sánchez-Moya, Y. (2021). Inundaciones y cambio climático: certezas e incertidumbres en el camino a la adaptación. Cuadernos de Geografía de la Universitat de València. 107:191-216. https://doi.org/10.7203/CGUV.107.2142419121610
The flavor problem and discrete symmetries
In this letter we propose a multi-Higgs extension of the standard model with
Abelian and non-Abelian discrete symmetries in which the mass matrices of the
charged fermions obtained from renormalizable interactions are diagonal.
Corrections induced by non-renormalizable interactions deviate these matrices
from the diagonal form. Active neutrinos acquire mass only from
non-renormalizable interactions. The main entries of the neutrino mass matrix
arise only through dimension five operators, while the diagonal entries arise
only from dimension six operators.Comment: 9 pages, no figures; Report No. corrected; new references added.
Version to be published in PL
The human endosalpinx : anatomical three-dimensional study and reconstruction using confocal microtomography
Purpose: To evaluate in three dimensions (3D) the human endosalpinx and reconstruct its surface along its different anatomical segments, without the injection or insertion of luminal contrasts, using confocal microtomography (micro-CT). Material and methods: 15 fallopian tubes (FT) from 14 women in reproductive age from procedures for benign disease or sterilization were selected. The specimens were fixed in formalin and stained with Lugol solution. Micro-CT studies were conducted on the specimens using protocols adapted from biological studies, to acquire images to reconstruct in 3D the endosalpinx surface. Results: From these specimens, 6 presented the intra-mural segment, 14 presented the isthmus and 15 presented the ampulla and fimbria segment of the FT. The specimen presented tissue definition, and contrast sufficient for FT endosalpinx morphological analysis and lumen definition. The intramural portion presented initially a mucosal projection toward the lumen, bending on its own axis, and increased numbers of projections towards the isthmic portion, where the projections become longer more numerous. The endosalpinx becomes more tortuous, the lumen diameter increases and the mucosal projections become more bulky in the ampullary portion, with the projections less present on the antimesenteric side. The infundibular portion is marked with the organized and predictable endosalpinx, the abdominal ostium is cleared demonstrated, with the reduction of the endosalpinx volume. The fimbria demonstrated a small relation between fringes and intratubal endosalpinx. Conclusions: Microscopic anatomy of different segments of the human FT mucosa can be analyzed and reconstructed in 3D with histological correlation using micro-CT
Reactive Distillation Applied to Biodiesel Production by Esterification: Simulation Studies
Reactive distillation is an operation that combines chemical reaction and separation in a single equipment, presenting various technical and economic benefits. In this chapter, an introduction to the reactive distillation process applied to the biodiesel industry was developed and complemented by case studies regarding the production of biodiesel through esterification a low-cost acid feedstock (corn distillers oil) and valorization of by-products (glycerol) through ketalization. The kinetic parameters of both reactions were estimated with an algorithm that performs the minimization of the quadratic differences between experimental and calculated data through a Nelder-Mead simplex method. A 4th order Runge Kutta method was employed to integrate the conversion or concentration equations used to describe the kinetics of the reactions in a batch reactor. Both processes were simulated in the commercial software Aspen Plus with the estimated kinetic parameters. The results obtained are promising and indicate that the productivity of both processes can be improved with the application of reactive distillation technologies. The simulated esterification process with an optimized column resulted in a fatty acids conversion increase of 84% in comparison to the values lower than 50% obtained in the experimental tests. Solketal production through ketalization also achieved a high glycerol conversion superior to 98%
Running Effects on Lepton Mixing Angles in Flavour Models with Type I Seesaw
We study renormalization group running effects on neutrino mixing patterns
when a (type I) seesaw model is implemented by suitable flavour symmetries. We
are particularly interested in mass-independent mixing patterns to which the
widely studied tribimaximal mixing pattern belongs. In this class of flavour
models, the running contribution from neutrino Yukawa coupling, which is
generally dominant at energies above the seesaw threshold, can be absorbed by a
small shift on neutrino mass eigenvalues leaving mixing angles unchanged.
Consequently, in the whole running energy range, the change in mixing angles is
due to the contribution coming from charged lepton sector. Subsequently, we
analyze in detail these effects in an explicit flavour model for tribimaximal
neutrino mixing based on an A4 discrete symmetry group. We find that for
normally ordered light neutrinos, the tribimaximal prediction is essentially
stable under renormalization group evolution. On the other hand, in the case of
inverted hierarchy, the deviation of the solar angle from its TB value can be
large depending on mass degeneracy.Comment: 36 pages, 4 figures; few references added and minor correction
Green extraction of glycosides from Stevia rebaudiana (Bert.) with low solvent consumption: A desirability approach
AbstractThe sweet flavor of Stevia rebaudiana (Bert.) leaf extract is well known and has raised the interest of huge food companies due to its natural bid. The extraction of their main glycosides stevioside and rebaudioside A is an important step on the preparation of final Stevia granules. The aim of the work reported here was to study and optimize the dynamic maceration of Stevia leaves using water and ethanol as green solvents. For instance, a fractional factorial design was chosen to evaluate the individual effects of the drug powder size, weight ratio of drug to solvent, temperature, agitation, and time on the yield of these glycosides. The glycosides were quantified by high pressure liquid chromatography. An exhaustive extraction by successive maceration steps showed that ethanol 70% was superior to water and ethanol 90% for stevioside and rebaudioside extraction. The liquid extract composition in dry basis and the yield of stevioside and rebaudioside A were significantly affected by the drug to solvent weight ratio, showing that larger volumes of solvent should be used. Furthermore, increasing solvent volume favors the extraction of the stevioside by a twofold factor as compared to rebaudioside A. Among the other factors, only drug powder size affected the yield of rebaudioside A significantly. The optimal solution for S. rebaudiana leaves dynamic extraction estimated by desirability functions methodology led to a condition which allows obtaining extraction yields of 2.31 and 1.24% for stevioside and rebaudioside A and their concentrations in dried extract corresponding to 8.38 and 4.51%, respectively. These high yields were obtained with drug to solvent ratio (1:10, w/w) much higher than previous works, thus resulting in a more sustainable and green process
- …