137 research outputs found
Determinación de las condiciones óptimas para la trilla de arveja (Pisum sativum)
Los sistemas de trilla de arveja usados tradicionalmente por los pequeños agricultores causan pérdidas elevadas tanto en calidad como en cantidad. Para mejorar tales sistemas se llevó a cabo el presente ensayo, se emplearon 2 tipos de cilindro, de dientes fijos y de dientes resortados, trabajando a 4 velocidades periféricas: 215, 465, 705 y 955 m/min. Se usó arveja de la variedad comercial Guatecana, cosechada con los siguientes contenidos de humedad: 13.7, 17.2, 21.1, 23.5, 44.7 por ciento. No se encontraron diferencias significativas en la operación de los 2 tipos de cilindro respecto a daño interno del grano y porcentaje de trilla. En cambio el daño visual del grano el cilindro de dientes resortados presentó valores inferiores. La velocidad del cilindro fue factor que más incidió en el porcentaje de grano trillado, mientras que la humedad del grano fue el que más influyó en el daño visual y el daño interno. Los mejores resultados se obtuvieron trillando grano con 17.2 por ciento de humedad y utilizando el cilindro de dientes resortados a velocidades de 705 y 905 m/min. Bajo estas condiciones, el porcentaje de grano trillado fue superior a 99.6 por ciento y el de grano sano superior a 97.3 por cientoArveja-Pisum sativu
Constraining scalar fields with stellar kinematics and collisional dark matter
The existence and detection of scalar fields could provide solutions to
long-standing puzzles about the nature of dark matter, the dark compact objects
at the centre of most galaxies, and other phenomena. Yet, self-interacting
scalar fields are very poorly constrained by astronomical observations, leading
to great uncertainties in estimates of the mass and the
self-interacting coupling constant of these fields. To counter this,
we have systematically employed available astronomical observations to develop
new constraints, considerably restricting this parameter space. In particular,
by exploiting precise observations of stellar dynamics at the centre of our
Galaxy and assuming that these dynamics can be explained by a single boson
star, we determine an upper limit for the boson star compactness and impose
significant limits on the values of the properties of possible scalar fields.
Requiring the scalar field particle to follow a collisional dark matter model
further narrows these constraints. Most importantly, we find that if a scalar
dark matter particle does exist, then it cannot account for both the
dark-matter halos and the existence of dark compact objects in galactic nucleiComment: 23 pages, 8 figures; accepted for publication by JCAP after minor
change
Evolution of Phenolic Content, Antioxidant Capacity and Phenolic Profile during Cold Pre-fermentative Maceration and Subsequent Fermentation of Cabernet Sauvignon Red Wine
The phenolic compound profile and content of red wines are modified during the maceration-fermentation process by several factors that alter the extractability of the compounds and by reactions that phenolic compounds undergo, and can be directly related to the quality of the final wine and its beneficial effects on the consumer. The aim of this study was to determine the change in phenolic content and profile during cold pre-fermentative maceration and fermentation without the removal of grape pomace. Total phenolics,flavonoids, anthocyanins, tannins and antioxidant capacity were determined by spectrophotometric methods, and the phenolic profile was determined by HPLC-MS on each day of the maceration-fermentation process. The results showed a variation in the content of phenolic compounds and antioxidant activity over time, but the final phenolic content showed no significative difference compared with the initial content (1 268 mg GAE/L and 1 115 mg GAE/L respectively). The phenolic profile showed that flavonoids were theprincipal compounds in wine and that they increased at the end of the winemaking. Condensed tannins also increased during fermentation, while anthocyanins and some phenolic acids decreased at the end of the process. The final content of phenolic compounds was similar to the initial one, but there was a change in the different fractions of phenolic compounds at the end of fermentation
P34 98. Leiomiomatosis con diseminación intravascular: Desde el útero a cavidades cardíacas y pulmón
ObjetivosLa leiomiomatosis uterina es un tumor mesenquimal poco frecuente, benigno, caracterizado por la proliferación de músculo liso en la luz vascular. Suele presentarse en mujeres de edad media, y presenta una enorme tendencia a la extensión intravascular y cardíaca. El tratamiento principalmente es quirúrgico para reducción de la masa tumoral, asociándose un bloqueo hormonal.MétodoPresentamos el caso de una mujer de 39 años, asintomática, con una plaquetopenia en estudio. Al realizarse una ecografía abdominal, se detecta una tumoración uterina de gran tamaño. La tomografía computarizada toracoabdominal objetivó extensión intravascular, a través de vena cava, extensión cardíaca hasta aurícula y ventrículo derecho, válvula tricúspide y arteria pulmonar hasta lechos parenquimatosos pulmonares.El tratamiento incluyó la realización de una histerectomía y doble anexectomía, asociándose una resección tumoral con acceso abdominal por laparotomía media desde cava inferior, y cirugía cardíaca con parada cardiocirculatoria, hipotermia profunda y perfusión anterógrada vía axilar, para resección tumoral intracardíaca.ResultadosLa evolución postoperatoria fue favorable. El estudio anatomopatológico diagnosticó una leiomiomatosis uterina con diseminación intravascular y cardíaca.ConclusionesLa leiomiomatosis uterina es una tumoración benigna con enorme tendencia a la extensión intravascular y cardíaca. Su tratamiento incluye resección tumoral y bloqueo hormonal de por vida, en mujeres jóvenes, generalmente. El tratamiento quirúrgico para resección tumoral exige control eco-cardiográfico para comprobar la completa resección del mismo
Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection
Most proposed dark matter candidates are stable and are produced thermally in
the early Universe. However, there is also the possibility of unstable (but
long-lived) dark matter, produced thermally or otherwise. We propose a strategy
to distinguish between dark matter annihilation and/or decay in the case that a
clear signal is detected in gamma-ray observations of Milky Way dwarf
spheroidal galaxies with gamma-ray experiments. The sole measurement of the
energy spectrum of an indirect signal would render the discrimination between
these cases impossible. We show that by examining the dependence of the
intensity and energy spectrum on the angular distribution of the emission, the
origin could be identified as decay, annihilation, or both. In addition, once
the type of signal is established, we show how these measurements could help to
extract information about the dark matter properties, including mass,
annihilation cross section, lifetime, dominant annihilation and decay channels,
and the presence of substructure. Although an application of the approach
presented here would likely be feasible with current experiments only for very
optimistic dark matter scenarios, the improved sensitivity of upcoming
experiments could enable this technique to be used to study a wider range of
dark matter models.Comment: 29 pp, 8 figs; replaced to match published version (minor changes and
some new references
Determining the WIMP mass using the complementarity between direct and indirect searches and the ILC
We study the possibility of identifying dark matter properties from
XENON-like 100 kg experiments and the GLAST satellite mission. We show that
whereas direct detection experiments will probe efficiently light WIMPs, given
a positive detection (at the 10% level for GeV), GLAST
will be able to confirm and even increase the precision in the case of a NFW
profile, for a WIMP-nucleon cross-section
pb. We also predict the rate of production of a WIMP in the next generation of
colliders (ILC), and compare their sensitivity to the WIMP mass with the XENON
and GLAST projects.Comment: 32 pages, new figures and a more detailed statistical analysis. Final
version to appear in JCA
Total quality management practices, competitive strategies and financial performance: the case of the Palestinian industrial SMEs
"This is an Accepted Manuscript of an article published by Taylor & Francis in Total Quality Management and Business Excellence on 19 Aug 2013, available online: http://wwww.tandfonline.com/10.1080/14783363.2013.824714."The purpose of this paper is to examine the relationship between Total Quality Management (TQM) practices, competitive strategies - cost leadership and differentiation- and firm performance in the Palestinian economy. Within this study total quality management has been conceptualized as soft and hard practices, in congruence with the literature. An empirical analysis based upon an extensive validation process was applied to refine TQM, competitive strategies and financial performance scales. Data were collected through surveying 202 in Palestinian industrial small and medium enterprises (SMEs). Structural Equation Modeling was carried out to test the anticipated relationships. Results derived from this study show that TQM practices have indirect, positive and significant relationship with financial performance through competitive strategies. In addition, a direct, positive and significant relationship between competitive strategies and financial performance was observed. Results derived from this study might help managers to implement TQM practices in order to effectively allocate resources and improve financial performance
Galactic-Centre Gamma Rays in CMSSM Dark Matter Scenarios
We study the production of gamma rays via LSP annihilations in the core of
the Galaxy as a possible experimental signature of the constrained minimal
supersymmetric extension of the Standard Model (CMSSM), in which
supersymmetry-breaking parameters are assumed to be universal at the GUT scale,
assuming also that the LSP is the lightest neutralino chi. The part of the
CMSSM parameter space that is compatible with the measured astrophysical
density of cold dark matter is known to include a stau_1 - chi coannihilation
strip, a focus-point strip where chi has an enhanced Higgsino component, and a
funnel at large tanb where the annihilation rate is enhanced by the poles of
nearby heavy MSSM Higgs bosons, A/H. We calculate the total annihilation rates,
the fractions of annihilations into different Standard Model final states and
the resulting fluxes of gamma rays for CMSSM scenarios along these strips. We
observe that typical annihilation rates are much smaller in the coannihilation
strip for tanb = 10 than along the focus-point strip or for tanb = 55, and that
the annihilation branching ratios differ greatly between the different dark
matter strips. Whereas the current Fermi-LAT data are not sensitive to any of
the CMSSM scenarios studied, and the calculated gamma-ray fluxes are probably
unobservably low along the coannihilation strip for tanb = 10, we find that
substantial portions of the focus-point strips and rapid-annihilation funnel
regions could be pressured by several more years of Fermi-LAT data, if
understanding of the astrophysical background and/or systematic uncertainties
can be improved in parallel.Comment: 33 pages, 12 figures, comments and references added, version to
appear in JCA
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