8,168 research outputs found
DOES SERVICE QUALITY MATTER IN MEASURING PERFORMANCE OF WATER UTILITIES?
Quality is a dimension of water services that has been repeatedly omitted in the study of performance of water utilities. In this paper, we make use of Data Envelopment Analysis techniques (DEA) to compute both conventional quantity-based and quality-adjusted indicators of technical efficiency for a sample of Spanish water utilities. The key assumptions are that a lack of quality (bad quality) can be regarded as a bad output, and the existence of a trade-off between quantity and quality. Our main results indicate that quality matters in measuring technical performance, the difference between conventional and quality-adjusted evaluations representing the opportunity cost of maintaining quality. Averages and distribution functions significantly differ between both assessments of performance, although water utilities do not seem to rank differently.water utilities; quality; Data Envelopment Analysis.
Pion scattering poles and chiral symmetry restoration
Using unitarized Chiral Perturbation Theory methods, we perform a detailed
analysis of the scattering poles and behaviour
when medium effects such as temperature or density drive the system towards
Chiral Symmetry Restoration. In the analysis of real poles below threshold, we
show that it is crucial to extend properly the unitarized amplitudes so that
they match the perturbative Adler zeros. Our results do not show threshold
enhancement effects at finite temperature in the channel, which
remains as a pole of broad nature. We also implement T=0 finite density effects
related to chiral symmetry restoration, by varying the pole position with the
pion decay constant. Although this approach takes into account only a limited
class of contributions, we reproduce the expected finite density restoration
behaviour, which drives the poles towards the real axis, producing threshold
enhancement and bound states. We compare our results with several
model approaches and discuss the experimental consequences, both in
Relativistic Heavy Ion Collisions and in and
reactions in nuclei.Comment: 17 pages, 9 figures, final version to appear in Phys.Rev.D, added
comments and reference
Síndrome de Kniest: aportación de 2 casos
Se comunican dos casos de síndrome de Kniest, con distinta evolución, ya que
el primero fallece a los 3 meses y medio de vida en tanto que el segundo evoluciona normalmente.
Se discute su etiopatogenia, se valora la anomalía de la colágena tipo II, como posible
factor causal de las alteraciones metafisoepifisarias, enanismo y lesiones oculares. Se revisa
la anatomía patológica de ambos pacientes en un caso por biopsia de cartílago condrocostal
y en el otro de cartílago accesorio de la cresta ilíaca. Se insiste en el diagnóstico diferencial
con aquellas formas de displasia que posiblemente se le parecen más, tales como el enanismo
metatrópico y la displasia disegmentaria en su forma más leve o tipo Rolland-Desbuqois.Two cases of Kniest's Syndrome with different evolution are reported. One died
before reaching the fourth month of life, while the other is still alive at 6 years of age. The
etiology and pathogenesis of this syndrome are discussed, paying special attention to the type
II colagen. A defect of this colagen would induce physes and epiphyses alterations, dwarfism
and ocular lesions. The chondrocostal cartilage in one case and accesory cartilage of iliac bone
in the other were biopsied, showing in both cases cytoplasmatic vacuolization of chondrocytes.
The differential diagnosis with metatropic dwarfism and disegmentarie dysplasia, in its midler
from or Rolland-Desbuqois type, is presented
Mobile Robot Lab Project to Introduce Engineering Students to Fault Diagnosis in Mechatronic Systems
This document is a self-archiving copy of the accepted version of the paper.
Please find the final published version in IEEEXplore: http://dx.doi.org/10.1109/TE.2014.2358551This paper proposes lab work for learning fault detection and diagnosis (FDD) in mechatronic systems. These skills are important for engineering education because FDD is a key capability of competitive processes and products. The intended outcome of the lab work is that students become aware of the importance of faulty conditions and learn to design FDD strategies for a real system. To this end, the paper proposes a lab project where students are requested to develop a discrete event dynamic system (DEDS) diagnosis to cope with two faulty conditions in an autonomous mobile robot task. A sample solution is discussed for LEGO Mindstorms NXT robots with LabVIEW. This innovative practice is relevant to higher education engineering courses related to mechatronics, robotics, or DEDS. Results are also given of the application of this strategy as part of a postgraduate course on fault-tolerant mechatronic systems.This work was supported in part by the Spanish CICYT under Project DPI2011-22443
Presencia y edad de vulcaniras en el Jurásico del Norte de Valencia (Cordillera Ibérica, España)
Se da cuenta en este trabajo de la presencia de rocas
volcánicas, intercaladas en las series carbonatadas del Jurásico del norte de la provincia de Valencia (región de Alcublas), cuya edad ha podido ser determinada como Bajociense inferior.
El hecho de que exista vulcanismo de edad similar en
gran parte de las codilleras Béticas(subbético), sugiere la existencia de una fase de distensión con marcada amplitud durante los primeros tiempos del Jurásico medio. Por otra parte,
las posibles emanaciones de sílice, acompañadas del proceso volcánico, pudieron ser unas de las causantes principales de la presencia ide nódulos de sílex en el Bajociense de una amplia región.Peer reviewe
COVID-19 Lockdown and Disney+ strategy on social networks on its launch during the State of alarm in Spain
The launch of Disney+ in Spain in March 2020 coincided with the Covid-19 pandemic and a period of home confinement for many Spaniards. This study examines the advertising and engagement strategy used by Disney+ on Twitter and Instagram, analyzing 2,268 messages. The platform’s social media use is similar to that of its competitors, with Twitter used for user engagement and Instagram used for content promotion. However, the study finds that the platform missed the opportunity to emphasize its unique qualities and appeal to the brand’s values. Despite this, Disney+ generated significant engagement during its launch month, reflecting high levels of user anticipation. Popular original productions such as The Mandalorian and Aladdin, as well as acquired content like The Simpsons, indicate the brand’s focus on a family or broad-spectrum target audience, in contrast to the younger and niche audiences favored by its competitors.La llegada de Disney+ a España en marzo de 2020 estuvo marcada por la pandemia del Covid-19. El periodo de confinamiento domiciliario entre la población española coincidió con la irrupción del nuevo servicio streaming de una de las marcas más conocidas y queridas a nivel mundial. Este estudio analiza la estrategia publicitaria y de engagement empleada por Disney+ en Twitter e Instagram. El análisis de contenido incluye 2.268 mensajes. Se aprecia un uso de las redes sociales similar a marcas competidoras como Netflix con un uso de Twitter para informar y responder a los comentarios de los usuarios; mientras que de Instagram se promueven nuevos contenidos, en especial películas. Se observa que en el intento de destacar sus elementos diferenciales como servicio bajo demanda, se pierde la oportunidad de apelar a los valores propios de la marca del ratón. La plataforma consiguió un mejor engagement durante el mes de lanzamiento, lo que muestra la alta expectativa de los usuarios. Entre las publicaciones más virales se encuentran producciones originales como The Mandalorian o Aladdín, pero también productos adquiridos como Los Simpson, y que apuntan al interés de la marca por un target familiar o de amplio espectro, frente a audiencias más jóvenes y de nicho valoradas por la competencia
Influencia de la relación tensión-deslizamiento en el comportamiento de la interfase FRP-Hormigón
En el presente trabajo se han analizado los modelos tensión-deslizamiento más divulgados para estudiar las tensiones en la interfase FRP-Hormigón y la carga máxima mediante su irapíementación en una de las principales técnicas de cálculo numérico fácilmente programable y aplicable para el caso en el que se tiene tracción en ambos extremos de la banda FRP. Los resultados se comparan con las soluciones analíticas encontradas en la literatura, las cuales están limitadas a los casos de una función tensión-deslizamiento lineal y bilineal. Finalmente, se contrasta la teoría con los resultados experimentales obtenidos de ensayos de tipología análoga al método beamtest empleado comúnmente para medir la adherencia de barras de acero
RadioAstron space VLBI imaging of polarized radio emission in the high-redshift quasar 0642 + 449 at 1.6 GHz
Lobanov, A.P. et. al.Context. Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the supermassive black holes in the centers of active galaxies. Aims. Space VLBI observations provide a unique tool for polarimetric imaging at a sub-milliarcsecond angular resolution and studying the properties of magnetic field in active galactic nuclei on scales of less than 10 gravitational radii. Methods. A space VLBI observation of high-redshift quasar TXS 0642+449 (OH 471), made at a wavelength of 18 cm (frequency of 1.6 GHz) as part of the early science programme (ESP) of the RadioAstron mission, is used here to test the polarimetric performance of the orbiting Space Radio Telescope (SRT) employed by the mission, to establish a methodology for making full Stokes polarimetry with space VLBI at 1.6 GHz, and to study the polarized emission in the target object on sub-milliarcsecond scales. Results. Polarization leakage of the SRT at 18 cm is found to be within 9% in amplitude, demonstrating the feasibility of high fidelity polarization imaging with RadioAstron at this wavelength. A polarimetric image of 0642+449 with a resolution of 0.8 mas (signifying an ∼4 times improvement over ground VLBI observations at the same wavelength) is obtained. The image shows a compact core-jet structure with low ( 2%) polarization and predominantly transverse magnetic field in the nuclear region. The VLBI data also uncover a complex structure of the nuclear region, with two prominent features possibly corresponding to the jet base and a strong recollimation shock. The maximum brightness temperature at the jet base can be as high as 4 × 10 K.Y.Y.K., M.M.L., K.V.S., P.A.V. are supported by the Russian Foundation for Basic Research (RFBR) grant 13-02-12103. K.V.S. is also supported by the RFBR grant 14-02-31789. J.L.G. acknowledges support from the Spanish Ministry of Economy and Competitiveness grant AYA2013-40825-P.Peer Reviewe
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