610 research outputs found
Colposuspensión para prevenir la incontinencia urinaria en perras castradas
Uno de los efectos secundarios de la ovariohisterectomía es la incontinencia urinaria. Ésta se presenta por dos motivos: en primer lugar, al eliminar los ovarios reducimos la fuente de estrógenos que son necesarios para favorecer la contracción muscular del esfínter urinario y, en segundo lugar, al eliminar el útero favorecemos que la vejiga, que se encuentra en posición pélvica, pase a posición abdominal. Cuando este animal envejece y engorda por efecto secundario de la ovariohisterectomía, todas las vísceras abdominales se apoyan sobre la vejiga y la comprimen. Esto, unido a una debilidad del esfínter vesical por la falta de los estrógenos, desemboca en que este animal se vuelva incontinente, primero cuando duerme y después a cualquier hora. El tratamiento médico de esta complicación tiene efectos secundarios muy graves; y en cuanto al quirúrgico, cuando se presenta el problema es difícil por la gran cantidad de grasa que tienen estos animales. Por este motivo, proponemos una técnica quirúrgica sencilla que los autores realizamos siempre al mismo tiempo que la ovariohisterectomía y que no prolonga más de cinco minutos la técnica completa, evitando así los problemas de incontinencia en hembras castradas
Experimental studies of QCD using flavour tagged jets with DELPHI
Identified and events from DELPHI are
used to measure the ratio of the mean charged particle multiplicity
distribution between gluon and quark jets. The dependence of this ratio with
the jet energy is established using about three million Z decays. Results
from all other detectors are discussed and compared. A nice agreement is found
among all them. The ratio between the normalized total three-jet cross sections
of and events is also
determined. The preliminary value obtained indicates that quarks are
experimentaly seen to radiate less than light quarks due to their higher mass.
The suggested experimental error is 300 MeV for the mass
determination at the M scale.Comment: Latex, 5 pages, 3 figures,to appear in the Proceedings of the High
Energy Physics International Euroconference on Quantum Chromodynamics (QCD
'96), Montpellier, France, 4-12th July 1996. Ed. S. Narison, Nucl Phys. B
(Proc. Suppl.
Evidence for a chemically differentiated outflow in Mrk 231
Aims: Our goal is to study the chemical composition of the outflows of active
galactic nuclei and starburst galaxies.
Methods: We obtained high-resolution interferometric observations of HCN and
HCO and of the ultraluminous infrared
galaxy Mrk~231 with the IRAM Plateau de Bure Interferometer. We also use
previously published observations of HCN and HCO and
, and HNC in the same source.
Results: In the line wings of the HCN, HCO, and HNC emission, we find
that these three molecular species exhibit features at distinct velocities
which differ between the species. The features are not consistent with emission
lines of other molecular species. Through radiative transfer modelling of the
HCN and HCO outflow emission we find an average abundance ratio
. Assuming a clumpy outflow,
modelling of the HCN and HCO emission produces strongly inconsistent
outflow masses.
Conclusions: Both the anti-correlated outflow features of HCN and HCO and
the different outflow masses calculated from the radiative transfer models of
the HCN and HCO emission suggest that the outflow is chemically
differentiated. The separation between HCN and HCO could be an indicator of
shock fronts present in the outflow, since the HCN/HCO ratio is expected to
be elevated in shocked regions. Our result shows that studies of the chemistry
in large-scale galactic outflows can be used to better understand the physical
properties of these outflows and their effects on the interstellar medium (ISM)
in the galaxy.Comment: 12 pages, 8 figures, accepted for publication in A&
Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate
Cation-exchange membranes made exclusively from ceramic materials have been synthesized by means of the impregnation of
microporous ceramic supports with zirconium phosphate. Changes in the pore size distribution and total pore volume of the supports
were provoked by the addition of starch as pore former in the fabrication procedure. This allowed the production of supports with
increased effective electrical conductivities and with larger pores available for the zirconium phosphate deposition. An improved
functionality for the exchange of cations was given to the ceramic membranes by means of their impregnation with the active particles of
zirconium phosphate. The ion-exchange properties of the membranes were increased with further impregnation cycles and the resulting
current voltage curves showed a similar shape to that typical of commercial polymeric ion-exchange membranes. The production of ionexchange
membranes with increased chemical and radiation stability will broaden their applicability for the treatment of specific
industrial waste waters, which are very aggressive for the current commercial ion-exchange membranes.Manuel-Cesar Marti-Calatayud wants to express his gratitude to Universitat Politecnica de Valencia for a postgraduate grant (Ref. 2010-12). S. Sales would like to express her gratitude to Ministerio de Ciencia e Investigacion (Spain) for a postgraduate grant (AP2009-4409). This work was supported by Ministerio de Ciencia e Innovacion (Spain) with the project numbers CTQ2008-06750-C02-01/PPQ and CTQ2008-06750-C02-02/PPQ.Martí Calatayud, MC.; García Gabaldón, M.; Pérez-Herranz, V.; Sales, S.; Mestre, S. (2013). Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate. Ceramics International. 39(4):4045-4054. https://doi.org/10.1016/j.ceramint.2012.10.255S4045405439
La agricultura marginal como fuente de sedimentos en el Pirineo Central
[Resumen] La agricultura cerealista ha ocupado grandes extensiones en los valles pirenaicos,
en exposiciones solanas por debajo de 1600 m de altitud. En este artículo se estudia el papel de la agricultura tradicional en la producción de sedimentos y la degradación del paisaje. Por medio de parcelas experimentales puede afirmarse que la agricultura itinerante y el barbecho han dado lugar a pérdidas de suelo muy elevadas y explican la pedregosidad superficial de mu.chas laderas. En el caso de la agricultura itinerante (articas), la quema de matorral y la incorporación de cenizas al suelo como fertilizante no contribuía a mejorar sustancialmente la
calidad de los suelos.[Abstract] Cereal cropping has occupied large extent in the Pyrenean valleys, on sunny aspects under 1.600 m a.s.l. In this paper the role of traditional farming on sediment yield and landscape degradation is studied. By means of experimental plots the authors conclude than shifting agriculture an fallow land have caused great soil losses and explain the surface stoniness in many hillslopes. In the case of shifting agriculture, the burning of the shrub cover and the use of ashes as fertilizer did not contribute to improve the quality of soil
Psychometric Study on a Two-Factor Higher Order Structure of Mindfulness, Its Effects, and Mechanisms Related to Mental Health among Experienced Meditators
Objective: To investigate the psychometric and structural properties of the Five Facets Mindfulness Questionnaire (FFMQ) among meditators, to develop a short form, and to examine associations of mindfulness with mental health and the mechanisms of mindfulness. Methods: Two independent samples were used, a German (n = 891) and a Spanish (n = 393) meditator sample, practicing various meditation styles. Structural and psychometric properties of the FFMQ were investigated with multigroup confirmatory factor analysis and exploratory structural equation modeling. Associations with mental health and mechanisms of mindfulness were examined with path analysis. Results: The derived short form broadly matched a previous item selection in samples of non-meditators. Self-regulated Attention and Orientation to Experience governed the facets of mindfulness on a higher-order level. Higher-order factors of mindfulness and meditation experience were negatively associated with symptoms of depression and anxiety, and perceived stress. Decentering and nonattachment were the most salient mechanisms of mindfulness. Aspects of emotion regulation, bodily awareness, and nonattachment explained the effects of mindfulness on depression and anxiety. Conclusions: A two-component conceptualization for the FFMQ, and for the study of mindfulness as a psychological construct, is recommended for future research. Mechanisms of mindfulness need to be examined in intervention studie
Chaos induced coherence in two independent food chains
Coherence evolution of two food web models can be obtained under the stirring
effect of chaotic advection. Each food web model sustains a three--level
trophic system composed of interacting predators, consumers and vegetation.
These populations compete for a common limiting resource in open flows with
chaotic advection dynamics. Here we show that two species (the top--predators)
of different colonies chaotically advected by a jet--like flow can synchronize
their evolution even without migration interaction. The evolution is
charaterized as a phase synchronization. The phase differences (determined
through the Hilbert transform) of the variables representing those species show
a coherent evolution.Comment: 5 pages, 5 eps figures. Accepted for publication in Phys. Rev.
Estimation of wood volume and height of olive tree plantations using airborne discrete-return LiDAR data
The aim of this study is to analyze methodologies based on airborne LiDAR (light detection and ranging) technology of low pulse density points (0.5m(-2)) for height and volume quantification of olive trees in Viver (Spain). A total of 29 circular plots, each with a radius of 20m, were sampled and their volumes and heights were obtained by dendrometric methods. For these estimations, several statistics derived from LiDAR data were calculated in each plot. Regression models were used to predict volume and height. The results showed good performance for estimating volume (R-2=0.70) and total height (R-2=0.67).The authors appreciate the financial support provided by the Spanish Ministerio de Ciencia e Innovacion (Ministry for Science & Innovation) within the framework of the project AGL2010-15334 and by the Vice-Rectorate for Research of the Universitat Politecnica de Valencia [Grant PAID-06-12-3297; SP20120534].Estornell Cremades, J.; Velázquez Martí, B.; López Cortés, I.; Salazar Hernández, DM.; Fernández-Sarría, A. (2014). Estimation of wood volume and height of olive tree plantations using airborne discrete-return LiDAR data. GIScience and Remote Sensing. 51(1):17-29. https://doi.org/10.1080/15481603.2014.883209S1729511Estornell, J., Ruiz, L. A., Velázquez-Martí, B., & Fernández-Sarría, A. (2011). Estimation of shrub biomass by airborne LiDAR data in small forest stands. Forest Ecology and Management, 262(9), 1697-1703. doi:10.1016/j.foreco.2011.07.026García, M., Riaño, D., Chuvieco, E., & Danson, F. M. (2010). Estimating biomass carbon stocks for a Mediterranean forest in central Spain using LiDAR height and intensity data. Remote Sensing of Environment, 114(4), 816-830. doi:10.1016/j.rse.2009.11.021Hyyppa, J., Kelle, O., Lehikoinen, M., & Inkinen, M. (2001). A segmentation-based method to retrieve stem volume estimates from 3-D tree height models produced by laser scanners. IEEE Transactions on Geoscience and Remote Sensing, 39(5), 969-975. doi:10.1109/36.921414Kim, Y., Yang, Z., Cohen, W. B., Pflugmacher, D., Lauver, C. L., & Vankat, J. L. (2009). Distinguishing between live and dead standing tree biomass on the North Rim of Grand Canyon National Park, USA using small-footprint lidar data. Remote Sensing of Environment, 113(11), 2499-2510. doi:10.1016/j.rse.2009.07.010Moorthy, I., Miller, J. R., Berni, J. A. J., Zarco-Tejada, P., Hu, B., & Chen, J. (2011). Field characterization of olive (Olea europaea L.) tree crown architecture using terrestrial laser scanning data. Agricultural and Forest Meteorology, 151(2), 204-214. doi:10.1016/j.agrformet.2010.10.005Næsset, E. (2004). Accuracy of forest inventory using airborne laser scanning: evaluating the first nordic full-scale operational project. Scandinavian Journal of Forest Research, 19(6), 554-557. doi:10.1080/02827580410019544Popescu, S. C. (2007). Estimating biomass of individual pine trees using airborne lidar. Biomass and Bioenergy, 31(9), 646-655. doi:10.1016/j.biombioe.2007.06.022Popescu, S. C., Wynne, R. H., & Nelson, R. F. (2002). Estimating plot-level tree heights with lidar: local filtering with a canopy-height based variable window size. Computers and Electronics in Agriculture, 37(1-3), 71-95. doi:10.1016/s0168-1699(02)00121-7Velázquez-Martí, B., Estornell, J., López-Cortés, I., & Martí-Gavilá, J. (2012). Calculation of biomass volume of citrus trees from an adapted dendrometry. Biosystems Engineering, 112(4), 285-292. doi:10.1016/j.biosystemseng.2012.04.011Velázquez-Martí, B., Fernández-González, E., Estornell, J., & Ruiz, L. A. (2010). Dendrometric and dasometric analysis of the bushy biomass in Mediterranean forests. Forest Ecology and Management, 259(5), 875-882. doi:10.1016/j.foreco.2009.11.027Velázquez-Martí, B., Fernández-González, E., López-Cortés, I., & Salazar-Hernández, D. M. (2011). Quantification of the residual biomass obtained from pruning of trees in Mediterranean olive groves. Biomass and Bioenergy, 35(7), 3208-3217. doi:10.1016/j.biombioe.2011.04.042Yu, X., Hyyppä, J., Kaartinen, H., & Maltamo, M. (2004). Automatic detection of harvested trees and determination of forest growth using airborne laser scanning. Remote Sensing of Environment, 90(4), 451-462. doi:10.1016/j.rse.2004.02.00
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