179 research outputs found
Intangibles factors and quality assessment of the service received in travel agencies
La adaptación de las agencias de viajes a los patrones de la Nueva
Economía nos conduce a una tendencia hacia la reestructuración del
sector, centrada en la búsqueda de nuevas estrategias competitivas. La
creciente importancia de los activos intangibles para la consecución de
dichas estrategias ha motivado este estudio, que trata de identificar
aquellos factores intangibles, presentes en la prestación de este servicio,
y que están directamente relacionados con la percepción, por parte del
cliente, de una diferenciación en el servicio recibido.Adaptation of travel agencies to the standards of the New Economy is
leading to a trend towards restructuring the sector aimed at finding new
competitive strategies. The growing importance of intangible assets in
achieving such strategies has motivated this study, which has tried to
identify those intangible factors, present in the provision of the service,
that have a direct relationship with the client´s perception of a
differentiation in the service received
Assessment of Cyfluthrin commercial formulation on growth, photosynthesis and catalase activity of green algae
Aquatic environments of the pampasic region of Argentina are severely affected by agricultural contamination due to an increase in a glyphosate tolerant transgenic variety of soybean crops. The present study is aimed to determine the effects of a commonly used Cyfluthrin commercial formulation (CCF) on growth, some physiological and biochemical parameter of four species of green algae. Significant inhibition of algal growth was observed from 0.1 mg Cyf/l. 96 h IC50 were between 0.92 and 4.85 mg Cyf/l. CCF caused algicidal effects. Photosynthesis was stimulated by 50% in Scenedesmus quadricauda cultures exposed to the lowest concentration (hormesis). Algal photosynthesis inhibition was observed at higher concentrations with IC50 values between 1.7 and 8.9 mg Cyf/l. Similar toxicity endpoints were found as a consequence of applying the traditional methodology of short-term chronic toxicity test of 96 h of exposition and the methodology developed using the Clark type photosynthetic oxygen evolution method. CAT activity was significantly increased between 23% and 33% considering the four species, at a lower concentration than those affecting algal growth and photosynthesis, indicating a potential biomarker. Taking into account that the extent of the soybean crops in the region is about fourteen million hectares, the improvement and extension of environmental tools for early detection of the action of pesticides on this essential group of organisms are discussed.Fil: Sáenz, María Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján; ArgentinaFil: Di Marzio, Walter Dario. Universidad Nacional de Luján; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alberdi, José Luis. Universidad Nacional de Luján; Argentin
Jet stability and the generation of superluminal and stationary components
We present a numerical simulation of the response of an expanding
relativistic jet to the ejection of a superluminal component. The simulation
has been performed with a relativistic time-dependent hydrodynamical code from
which simulated radio maps are computed by integrating the transfer equations
for synchrotron radiation. The interaction of the superluminal component with
the underlying jet results in the formation of multiple conical shocks behind
the main perturbation. These trailing components can be easily distinguished
because they appear to be released from the primary superluminal component,
instead of being ejected from the core. Their oblique nature should also result
in distinct polarization properties. Those appearing closer to the core show
small apparent motions and a very slow secular decrease in brightness, and
could be identified as stationary components. Those appearing farther
downstream are weaker and can reach superluminal apparent motions. The
existence of these trailing components indicates that not all observed
components necessarily represent major perturbations at the jet inlet; rather,
multiple emission components can be generated by a single disturbance in the
jet. While the superluminal component associated with the primary perturbation
exhibits a rather stable pattern speed, trailing components have velocities
that increase with distance from the core but move at less than the jet speed.
The trailing components exhibit motion and structure consistent with the
triggering of pinch modes by the superluminal component.Comment: Accepted by ApJ Letters. LaTeX, 19 pages, 4 PostScript figure
Cyto and genotoxicity of positive and negative coated Silica nano particles on Celomocytes of earthworms Eisenia fetida (Oligocheta, Annelida)
To understand and assess the effects of nanoparticles (NPs) on the environment, should be well established quantitatively the concentration-response relationships. Also relate the potential effects on selected variables of response with the exposure to sub-lethal levels of NPs. In this work, we describe the ecotoxicological evaluation of negative and positive coated silica NPs (Si-Nps) on coelomic cells from Eisenia fetida. The cytotoxicity of earthworm coelomocytes, expressed as LC50-1hour, was equal to 73.94 and 116.93 μg/mL for positive and negative Si-NPs, respectively. Genotoxicity were determined on the basis that the Si-NPs promote the generation of reactive oxygen species (ROS) once added on cell membranes, or entered in cells. In this case both types of NPs were genotoxics even at the lowest tested concentration equal to 1 μg/mL.Fil: Di Marzio, Walter Dario. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Curieses, Silvana Patricia. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alberdi, José Luis. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; ArgentinaFil: Sáenz, María Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentin
Genotoxic evidences of glyphosate and chlorpyriphos on eisenia fetida coelomocytes
The organophosphorus herbicide glyphosate (GLY) and the organophosphate insecticide chlorpyriphos (CPF) are key pesticides in modern management cultures worldwide. Sublethal toxicity of the commercial herbicide formulation Roundup® and the insecticide formulation Terfos® were evaluated on Eisenia fetida coelomocytes exposed under in vivo and ex vivo laboratory conditions. Induction of DNA single-strand breaks evaluated by the single cell gel electrophoresis assay and coelomocyte viability as well as alterations in coelomocyte trophic indexes were employed as endpoints for genotoxicity and cytotoxicity, respectively. Specimens were exposed at concentrations corresponding to recommended pesticide field application rate, and endpoints were evaluated after 7 and 14 days of treatment (in vivo exposure). In addition, coelomocytes were exposed to aqueous leachate of pesticide-contaminated soils during 1 h (ex vivo exposure). Earthworms exposed to Roundup® and Terfos® showed an increased frequency of DNA damage. Also, a decrease of coelomocyte viability and decrease of trophic indexes were observed in all treatments. The results demonstrate that either GLY- and CPF-based formulations exerted genotoxic as well as cytotoxic effects in coelomocytes of E. fetida exposed in vivo and ex vivo.Fil: Curieses, Silvana Patricia. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sáenz, María Elena. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alberdi, José Luis. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; ArgentinaFil: Martinez, Ricardo Santiago. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Larramendy, Marcelo Luis. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Di Marzio, Walter Dario. Universidad Nacional de Luján. Departamento de Ciencias Básicas. Programa de Investigación en Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
IAA : Información y actualidad astronómica (6)
Sumario : Investigación: Colisiones entre galaxias.--
Pulsación estelar: nuevas técnicas, nuevos avances.--
Ventana Abierta: The Black Hoyle.-- Charlas con...Ricardo Amils.-- Actualidad Científica: El “impactante” nacimiento de la Luna.--
Descubrimiento de agua en una nebulosa planetaria.--
Actividades IAA.--
Agenda.Esta revista se publica con la ayuda de la Acción Especial DIF 2001-4284-E del Programa Nacional de Difusión de la Ciencia y la Tecnología, del Ministerio de Ciencia y Tecnología.N
Accesibilidad y turismo en el parque nacional de Monfragüe
En los últimos años ha habido un aumento espectacular de la demanda de turismo en
espacios naturales protegidos, en el caso de España esa demanda se cifra en
aproximadamente 10 millones de visitantes. Al tiempo, también se ha incrementado el
turismo llevado a cabo por personas con algún tipo de discapacidad, siendo éste un
segmento de mercado que alcanza en España cerca de 3,5 millones de personas, en
Europa 50 millones y en el mundo alrededor de 500 millones. Si partimos de la premisa
de que toda persona tiene derecho a disfrutar del medio ambiente, las áreas de uso
público de los espacios naturales protegidos deberían ir adaptándose y normalizándose
para un uso social generalizado de las mismas. En este trabajo se presentan las
principales conclusiones del proyecto de investigación “Las áreas de uso público en la
Reserva de la Biosfera de Monfragüe. Accesibilidad y capacidad de carga” (Orden
MAM 321/2007; No Exp. 024/SGTB/2007 4.1), que ponen de relieve las principales
necesidades en materia de accesibilidad y adaptación de las mismas para permitir que el
uso público tenga un carácter universal.In the last years there has been a spectacular increase of the demand of tourism in
natural protected spaces, in case of Spain this demand codes in approximately 10
millions of visitors. To the time, also there has been increased the tourism carried out by
persons with some type of disability, being this one a segment of market that reaches in
Spain near 3,5 million persons, in Europe 50 million and in the world about 500 million.
If we depart from the premise from that every person has right to enjoy the
environment, the areas of public use of the natural protected spaces should go adapting
and settling down for a social widespread use of the same ones.
In this work they present the principal conclusions of the project of investigation "The
areas of public use in the Reserve of Monfragüe's Biosphere. Accessibility and capacity
of load" (Order MAM 321/2007; N o Exp. 024/SGTB/2007 4.1), that emphasize the
principal needs as for accessibility and adjustment of the same ones to allow that the
public use should have a universal character.Secretaría general de empleo, actividad empresarial e innovación tecnológica del Gobierno de Extremadura. Ayuda a los grupos de investigación catalogados (Ref.: 2010/00491/001
IAA : Información y actualidad astronómica (29)
Sumario : Sunrise, una aventura polar.--
Nuestra tormentosa estrella.--
¿Son válidos los modelos de atmósferas estelares?.--
¿Viajaremos más rápido que la luz?.--
HISTORIAS DE ASTRONOMÍA. Últimas tardes con Hipatia.--
DECONSTRUCCIÓN Y otros ENSAYOS. Edwin Hubble.--
EL “MOBY DICK” DE... Antxon Alberdi (IAA-CSIC).--
ACTUALIDAD.--
Betelgeuse en ebullición.--
¿Qué supone el hallazgo de glicina en el cometa 81P/Wild?.--
¿Existe el cinturón de Gould?.--
Cosmología de alta precisión con supernovas.--
Púlsares silenciosos en radio pero ruidosos en rayos gamma.--
El Quinteto de Stéphan.--
Ecos gravitatorios del Universo primordial.--
Júpiter castigado.--
ENTRE BASTIDORES.--
CIENCIA: PILARES E INCERTIDUMBRES :
Formación de estrellas masivas.N
Maxillary peripheral keratocystic odontogenic tumor. A clinical case report
The keratocystic odontogenic tumor is a benign odontogenic cystic neoplasia characterized by its thin, squamous epithelium with superficial parakeratosis. It has the potential for infiltration and local aggressiveness and has a high rate of recurrence.
This neoplasia is predominantly found in males and people of white origin. The mandible is the most frequently involved site, in particular the third molar region, mandibular angle, and ramus. It has a mandible-maxilla ratio of 2:1. Only about twenty cases of peripheral keratocystic odontogenic tumors (PKCOT) have been reported in the international literature.
This study presents a case of PKCOT localized in the anterior region of the maxilla, on the vestibular side of the upper left lateral incisor and the upper left canine. The diagnosis and treatment procedures, as based on the literature, are also discussed
- …