1,560 research outputs found
Non-local Thirring model at finite-temperature
We extend a recently proposed non-local and non-covariant version of the
Thirring model to the finite-temperature case. We obtain a completely bosonized
expression for the partition function, describing the thermodynamics of the
collective modes which are the underlying excitations of this system. From this
result we derive closed formulae for the free-energy, specific-heat, two-point
correlation functions and momentum distribution, as functionals of
electron-electron coupling potentials.Comment: 23 pages, latex, no figure
Corporate blogging in Spanish companies. Design and application of a quality index (ICB)
Blogs have strengthened its position as an online communication tool to increase the dialogue between organizations and their publics, and this thanks to their interactive capacity and easy use. Although blogs didn’t enjoy the popularity and swift penetration of social networks, Spanish companies are gradually incorporating this channel to their Public Relations plans. Thus, it becomes increasingly interesting to develop a quantitative index allowing determining the degree of compliance to excellence criteria. This paper aims to identify the main factors in order to value the quality of a corporate blog, describes the design of the evaluation index and, later, applies this index to study the corporate blogs of the main Spanish companies in order to unveil how they are exploiting its many advantages
Spectral Inversion of Multi-Line Full-Disk Observations of Quiet Sun Magnetic Fields
Spectral inversion codes are powerful tools to analyze spectropolarimetric
observations, and they provide important diagnostics of solar magnetic fields.
Inversion codes differ by numerical procedures, approximations of the
atmospheric model, and description of radiative transfer. Stokes Inversion
based on Response functions (SIR) is an implementation widely used by the solar
physics community. It allows to work with different atmospheric components,
where gradients of different physical parameters are possible, e.g., magnetic
field strength and velocities. The spectropolarimetric full-disk observations
were carried out with the Stokesmeter of the Solar Telescope for Operative
Predictions (STOP) at the Sayan Observatory on 3 February 2009, when neither an
active region nor any other extended flux concentration was present on the Sun.
In this study of quiet Sun magnetic fields, we apply the SIR code
simultaneously to 15 spectral lines. A tendency is found that weaker magnetic
field strengths occur closer to the limb. We explain this finding by the fact
that close to the limb, we are more sensitive to higher altitudes in an
expanding flux tube, where the field strength should be smaller since the
magnetic flux is conserved with height. Typically, the inversions deliver two
populations of magnetic elements: (1) high magnetic field strengths (1500-2000
G) and high temperatures (5500-6500 K) and (2) weak magnetic fields (50-150 G)
and low temperatures (5000-5300 K).Comment: 10 pages, 6 figures, accepted for Solar Physic
Evaluation of metabolic and biochemical blood parameters in lactating cows with Cystic Ovarian Disease
The aim of the study was to determine and evaluate different blood parameters associated to energetic,
protein, mineral and liver metabolic processes together with productive and reproductive parameters
in dairy cows of Santa Fe province (Argentina) that were diagnosed with cystic ovarian disease
(COD). Lactating Argentine Holstein cows from five dairy herds with spontaneous COD (n= 80)
diagnosed by ultrasound and control cows (n= 124) were included in the study. Blood samples were
obtained from all cows to determine serum concentrations of: growth hormone, insulin-like growth
factor (IGF-1), insulin, aspartate aminotransferase, alkalin phosphatase, gamma glutamiltransferase,
albumin, total proteins, albumin: globulin ratio, total and direct bilirrubin, ?-hidroxibutirate,
colesterol, glucose, urea, creatinin, calcium, phosphorus and magnesium. Serum concentrations
of insulin and IGF-1 were lower (P<0.05) in COD than control cows. No significant differences
among groups were observed in any other variables studied, however, the calving to conception
interval was higher in cows with COD compared to controls. These results allowed us to conclude
that there would be an association between blood concentrations of IGF-1 and insulin and COD
that, ultimately, compromise the reproductive performance of the cow.Fil: Cattaneo, L. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Teriogenología. Santa Fe, ArgentinaFil: Barberis, F.C. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Teriogenología. Santa Fe, ArgentinaFil: Stangaferro, M.L. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Teriogenología. Santa Fe, ArgentinaFil: Signorini, M.L. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. ArgentinaFil: Signorini, M.L. CONICET. ArgentinaFil: Ruiz, M.F. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Hospital de Salud Animal. Santa Fe, ArgentinaFil: Zimmermann, R. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Hospital de Salud Animal. Santa Fe, ArgentinaFil: Bo, G.A. Instituto de Reproducción Animal Córdoba (IRAC). ArgentinaFil: Hein, G.J. CONICET - Universidad Nacional del Litoral. Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral). Esperanza, ArgentinaFil: Ortega, H.H. CONICET - Universidad Nacional del Litoral. Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral). Esperanza, ArgentinaEl objetivo de este trabajo fue determinar y evaluar indicadores bioquímicos sanguíneos asociados
a procesos metabólicos energéticos, proteicos, minerales y de funcionalidad hepática, junto con
parámetros productivos y reproductivos en vacas lecheras que fueron diagnosticadas con enfermedad
quística ovárica (COD) y controles. Se emplearon vacas Holando Argentino en lactancia de 5
rebaños de la provincia de Santa Fe (Argentina) que presentaban COD (n= 80) diagnosticada
mediante ultrasonografía y controles clínicamente sanas (n= 124). De las vacas se obtuvo sangre
coccígea para determinar las concentraciones séricas de las hormonas de crecimiento (GH), factor
de crecimiento similar a la insulina-1 (IGF-1) e insulina, la actividad sérica de AST, FA, GGT y las
concentraciones séricas de albúmina, proteínas totales, relación albúmina: globulinas, bilirrubina
total y directa, ?-hidroxibutirato, colesterol, glucosa, urea, creatinina, calcio, fósforo y magnesio.
Las concentraciones séricas de insulina e IGF-1 fueron menores (P<0,05) en las vacas con COD
que en las controles. No se observaron diferencias significativas (P>0,05) entre ambos grupos en
las demás variables séricas y productivas evaluadas, sin embargo, el intervalo parto-concepción fue
mayor en vacas que presentaron COD. Los resultados nos permitieron concluir que habría una
asociación entre los valores séricos de IGF-1 e insulina y la COD, y que ésta comprometería el
futuro reproductivo de las vacas
Investigación cualitativa en mujeres víctimas de violencia de género
ObjetivoAnalizar la experiencia de mujeres víctimas de la violencia de género atendidas en centros de atención primaria desde el punto de vista de las mujeres.DiseñoInvestigación cualitativa interpretativa. Perspectiva fenomenológica.EmplazamientoEstudio multicéntrico en centros de salud urbanos.ParticipantesMujeres víctimas de la violencia de género (física, psíquica, sexual)atendidas en los centros de salud. Muestreo intencional y teórico hasta el punto de saturación. Criterios de segmentación: edad (jóvenes-edad media-ancianas); maltrato actual o pasado; detección en urgencies-consultas.Mediciones principalesRelatos biográficos y análisis de contenido de la transcripción literal de las grabaciones. Codificación mediante programa NUD-IST. Utilización para la interpretación de la Teoría Fundamentada.LimitacionesComplejidad del fenómeno de estudio. Proyección de la perspectiva del investigador. Volumen ingente de datos. Se proponen estrategias para mejorar la credibilidad, la conformabilidad y la transferibilidad.Aplicabilidad prácticaMejorar el conocimiento de la situación de las mujeres víctimas de la violencia doméstica desde una perspectiva no directiva, lo que permitirá mejorar la calidad de las intervenciones.ObjectiveTo analyse, from the point of view of the women, the experience of women who are victims of male violence and attended at primary care centres.DesignInterpretative, qualitative research. Phenomenological perspective.SettingMulti-centre study in urban health centres.ParticipantsWomen victims of male violence (physical, psychological, or sexual) seen at health centres. Intention andtheoretical sampling to saturation point.Segmentation criteria: age (young/middle-aged/elderly); current or past ill-treatment; detection in casualty/consultations.Main measurementsBiographical accounts and content analysis of recordings’ literal transcription. Coding through the NUDIST programme. Use for interpreting Well-Founded Theory.LimitationsComplexity of the phenomenon under study. Projection of researcher’s perspective. Huge amount of data. Strategies are proposed for increasing credibility, conformity and transferability.Practical useTo improve understanding of the situation of women who are victims of domestic violence, from a non-directive perspective that enables the quality of interventions to be improved
Detection of pollution transport events southeast of Mexico City using ground-based visible spectroscopy measurements of nitrogen dioxide
This work presents ground based differential optical absorption spectroscopy (DOAS) measurements of nitrogen dioxide (NO<sub>2</sub>) during the MILAGRO field campaign in March 2006 at the Tenango del Aire research site located to the southeast of Mexico City. The DOAS NO<sub>2</sub> column density measurements are used in conjunction with ceilometer, meteorological and surface nitric oxide (NO), nitrogen oxides (NO<sub>x</sub>) and total reactive nitrogen (NO<sub>y</sub>) measurements to analyze pollution transport events to the southeast of Mexico City during the MILARGO field campaign. The study divides the data set into three case study pollution transport events that occurred at the Tenango del Aire research site. The unique data set is then used to provide an in depth analysis of example days of each of the pollution transport events. An in depth analysis of 13 March 2006, a Case One day, shows the transport of several air pollution plumes during the morning through the Tenango del Aire research site when southerly winds are present and demonstrates how DOAS tropospheric NO<sub>2</sub> vertical column densities (VCD), surface NO<sub>2</sub> mixing ratios and ceilometer data are used to determine the vertical homogeneity of the pollution layer. The analysis of 18 March 2006, a Case Two day, shows that when northerly winds are present for the entire day, the air at the Tenango del Aire research site is relatively clean and no major pollution plumes are detected. Case 3 days are characterized by relatively clean air throughout the morning with large DOAS NO<sub>2</sub> enhancements detected in the afternoon. The analysis of 28 March 2006 show the DOAS NO<sub>2</sub> enhancements are likely due to lightning activity and demonstrate how suitable ground-based DOAS measruements are for monitoring anthropogenic and natural pollution sources that reside above the mixing layer
Virtualization of pliocene sites in the Huelva province: valuating the paleontological heritage in differentiate educative settings I
El patrimonio paleontológico del Plioceno de la provincia de Huelva es uno
de los más importantes de España y referente europeo de moluscos de este
período. Sin embargo, no existe un inventario de catalogación básica de los
principales yacimientos ni de los principales grupos fósiles presentes, así como
de su importancia como patrimonio natural. El presente trabajo pretende rellenar
este notable vacío con una proyección tanto hacia materias preuniversitarias
como universitarias, así como hacia posibles instituciones y corporaciones
públicas susceptibles de utilizarlo en sus planes de ordenación. Por otro lado, se
pretende que actúe como mecanismo de interconexión entre titulaciones con bajo
número de alumnos de nuevo ingreso y los centros de Bachillerato, de forma que
incentive una posible elección de estos Grados por los alumnos de las opciones
científico-tecnológicas. También puede ser interesante para captar egresados
hacia Másteres Oficiales en Patrimonio Histórico y Natural. En este sentido, se
ha realizado un DVD documental sobre el patrimonio paleontológico del
Plioceno de la provincia de Huelva, concretamente de las formaciones “Arenas
de Huelva” y “Arenas de Bonares” desarrolladas en ambientes marinos someros
y costeros durante la última etapa de evolución neógena de la cuenca. Este
documental incluye una visión de conjunto de los principales yacimientos fósiles
de esta edad, así como una explicación de la evolución paleogeográfica de
nuestra provincia y los organismos que la han caracterizado en los últimos
millones de años. Esta aportación es aplicable en el trabajo de campo de varios
Grados y Posgrados universitarios y de fácil uso como material didáctico en
diversas asignaturas de E.S.O. y Bachillerato. Este trabajo se ha realizado en el
marco del proyecto de innovación docente (PID nº 10050) de la Universidad de
Huelva.The paleontological heritage from the Neogene in the province of Huelva is
one of the most important in Spain and it is considered a European reference site
for the mollusk fossil record from this period. However, there are not basic
inventories neither for the main sites nor the major fossil groups. Furthermore,
no inventories exist about their natural heritage importance. This work aims to
fill this significant gap for both pre-university and university levels, as well as to
public institutions and corporations that may use it in their management plans. In
addition, it is intended to act as an linking mechanism between university
degrees with low number of first-year students and high school centres, in order
to encourage a possible choice of these Bachelor’s degrees by scientific and
technological students. It may also be interesting to catch the attention of
graduates for Official Masters in Historical and Natural Heritage. In this sense, a
DVD-documentary has been made about the paleontological heritage from the
Pliocene in the province of Huelva, specifically from the “Arenas de Huelva”
and “Arenas de Bonares” formations. These units were developed in shallow
marine and coastal environments during the last stage of the Neogene evolution
in the Guadalquivir Basin. This documental includes an overview of main marine
fossil sites from this age and a brief explanation of the palaeogeographic
evolution of the Huelva province during the last million of years. This
contribution is useful for the fieldwork at Bachelor and Master Degree level and
it is easy to use as teaching materials in different ESO (Obligatory Secondary
Teaching) and High School subjects. This work has been support for an
Innovation in Teaching Project (PID No. 10050) of the Huelva University
Calibración de una nariz electrónica tipo QCM y relación con las especificaciones para la calidad de la pera.
Las microbalanzas de cristal de cuarzo (QCM), son mecanismos piezoeléctricos, para transformarlos en sensores químicos es necesario recubrirlos con una capa de material capaz de capturar las moléculas del ambiente. Cuando una masa es adsorbida sobre la superficie del cristal, la frecuencia de oscilación cambia en proporción a la cantidad de masa (Di Natale et al. 1997). La respuesta de los sensores depende de numerosos factores que pueden ser difíciles de controlar, tales como la temperatura y la humedad del gas portador. Todos estos factores producen cambios en la selectividad de los sensores que afectan a la reproducibilidad de las medidas. A pesar de la existencia de numerosos estudios no existe ningún procedimiento establecido para la calibración de las QCM en relación con la sensibilidad necesaria en los sensores para el aseguramiento de la calidad en pera o en otras frutas
Biometry and plasmatic stress-related parameters in brill (Scophthalmus rhombus)cultured at different stocking densities.
The effects of the stocking density on the physiological stress and biometric features of the brill were studied. Fish (491±20 g) were cultured at three different stocking densities: 1; 5 and 15 Kg m-2 (LSD, MSD and HSD) during 5 weeks. Survival and several biometric, feeding and plasmatic parameters were assessed. Although final weight and specific growth rate decreased in higher densities, there were not significant differences between MSD and HSD. Differences for survival rate, feed efficiency, conversion index and feed intake were not detected among treatments. The minimum HSI was found in the HSD treatment, and condition factor varied inversely regards to stocking density. Plasma cortisol and osmolality were directly related to stocking density though the former was not significantly different among treatments. Plasma lactate and glucose significantly increased while stocking density rose. Nevertheless, free fatty acids did not vary among treatments, and triglycerides only decreased in LSD.
This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund).www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.
Se estudiaron los efectos de la densidad de cultivo sobre el estrés fisiológico y parámetros biométricos en el parracho. Los peces (491±20 g) fueron cultivados a tres densidades diferentes: 1; 5 y 15 Kg m-2 (LSD, MSD y HSD) durante 5 semanas. El peso final y crecimiento decrecieron con la densidad, pero no hubo diferencias significativas entre MSD y HSD. No se detectaron diferencias significativas entre tratamientos para supervivencia, eficiencia alimentaria, índice de conversión y tasa de ingestión. El HIS mínimo fue para la HSD y el factor de condición varió inversamente a la densidad. La osmolalidad y el cortisol, glucosa y lactato plasmáticos estuvieron directamente relacionados con la densidad. Sin embargo, los ácidos grasos libres no variaron entre tratamientos.
Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E , financiado por el FEDER (Fondo Europeo de Desarrollo Regional).www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p
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