1,142 research outputs found
Perceived value of advanced mobile messaging services: A cross-cultural comparison of Greek and Spanish users
Purpose
The purpose of this paper is to analyse the role of perceived value on post-acceptance behaviour for users of advanced mobile messaging services (AMMS). The paper also compares differences in the influence of perceived value on satisfaction and of satisfaction on loyalty to AMMS in Spain and Greece, to test the moderating effect of culture.
Design/methodology/approach
Partial least squares path modelling is used to test the model. Perceived value is modelled as a multidimensional reflective construct with four dimensions. Culture is studied at a national level. Differences between countries are tested using the multigroup analysis approach proposed by Henseler et al. (2009).
Findings
Perceived value contributes significantly to satisfaction. Satisfaction also has a significant effect on loyalty. Regarding the moderating effect of culture, the influence of perceived value on satisfaction is higher in Greece than in Spain. The authors report similar findings for the effect of satisfaction on loyalty, demonstrating the relevant moderating role of cultures with different degrees of masculinity, uncertainty avoidance and collectivism.
Practical implications
This cross-cultural comparison enables mobile phone companies to understand how to provide the greatest value with AMMS in each country in order to increase user satisfaction and loyalty to the service.
Originality/value
This is one of the first studies that develops cross-cultural research to analyse the post-acceptance of mobile services. It analyses the effect of perceived value and satisfaction, making an original comparison of two countries generally considered too similar to be compared
Vegetation and Arthropod Responses to Brush Reduction by Grubbing and Stacking
Grubbing is a mechanical brush-reduction technique that allows targeting of mesquite (Prosopis glandulosa) and huisache (Vachellia farnesiana) and can be used to open lanes for hunting northern bobwhites (Colinus virginianus). Follow-up treatments of stacking allow the piling up of downed brush. We initiated this study on the Santa Gertrudis Division of the King Ranch, Inc., Texas, to determine effects of grubbing and stacking on vegetation and arthropod communities important to bobwhite. We hypothesized that grubbing and stacking would be able to selectively remove mesquite and huisache while leaving mixed brush species largely intact. We hypothesized that soil disturbance treatments would lead to improved brooding, feeding, and nesting habitat for bobwhite through an increase in herbaceous food plants, arthropods, and nesting cover. We sampled vegetation prior to treatment during July 2012 and posttreatment during November 2012, March 2013, and July 2013. We sampled arthropods before treatment in July 2012 and monthly posttreatment until July 2013, a year marked by extreme drought in South Texas. We detected a positive response of bobwhite food grasses and/or sedges 1 year after initial treatments but detected no treatment effect on bobwhite food forbs. We detected no effects of treatments on nesting cover. Grubbing and stacking did not affect total Insecta abundance; however, Insecta biomass and Arachnida abundance and biomass responded both positively and negatively to treatments. To better understand the effects of grubbing and stacking, replication of this study during years of average and above average precipitation should be conducted
In vivo activity of plant-based interleukin-12 in the lung of Balb/c mouse
<p>Abstract</p> <p>Background</p> <p>In the last years, plants are being used for the production of a wide variety of biopharmaceuticals, including cytokines, and have the potential to serve as vehicles for mucosal administration of these molecules. We had previously reported the expression of a cytokine, interleukin-12 (IL-12), in transgenic tomato plants and had demonstrated that it retained its biologic activity <it>in vitro</it>.</p> <p>Findings</p> <p>In this work, we administered crude extracts of IL-12-containing tomato fruits to mice through the intratracheal route, measuring endogenous IL-12 and determining biologic activity by quantification of interferon-gamma (IFN-γ) in lungs and by histological analysis. IFN-γ expression in lungs, as well as histological analysis, indicate that tomato-expressed IL-12 retains its biologic activity and, most importantly, its effects are restricted to the site of administration.</p> <p>Conclusion</p> <p>Our results indicate that the functional activity of tomato-expressed IL-12 is comparable to that of commercial recombinant IL-12 when given via the mucosal route. This opens the possibility of using crude extracts prepared from tomatoes expressing IL-12 for certain immunotherapies.</p
Development and automation of photobioreactors for microalgae intensive cultures for the use in industrial gas studies
Peer Reviewe
Two-step ATP-driven opening of cohesin head
The cohesin ring is a protein complex composed of four core subunits: Smc1A, Smc3, Rad21 and Stag1/2. It is involved in chromosome segregation, DNA repair, chromatin organization and transcription regulation. Opening of the ring occurs at the "head" structure, formed of the ATPase domains of Smc1A and Smc3 and Rad21. We investigate the mechanisms of the cohesin ring opening using techniques of free molecular dynamics (MD), steered MD and quantum mechanics/molecular mechanics MD (QM/MM MD). The study allows the thorough analysis of the opening events at the atomic scale: I) ATP hydrolysis at the Smc1A site, evaluating the role of the carboxy-terminal domain of Rad21 in the process; ii) the activation of the Smc3 site potentially mediated by the movement of specific amino acids; and iii) opening of the head domains after the two ATP hydrolysis events. Our study suggests that the cohesin ring opening is triggered by a sequential activation of the ATP sites in which ATP hydrolysis at the Smc1A site induces ATPase activity at the Smc3 site. Our analysis also provides an explanation for the effect of pathogenic variants related to cohesinopathies and cancer
Monitorización de los niveles de inmisión de COVs en el aire ambiente de la Isla de Tenerife
Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna
Liquid methanol Monte Carlo simulations with a refined potential which includes polarizability, nonadditivity, and intramolecular relaxation
Monte Carlo simulations of liquid methanol were performed using a refined ab initio derived potential which includes polarizability, nonadditivity, and intramolecular relaxation. The results present good agreement between the energetic and structural properties predicted by the model and those predicted by ab initio calculations of methanol clusters and experimental values of gas and condensed phases. The molecular level picture of methanol shows the existence of both rings and linear polymers in the methanol liquid phase
Surfaces roughness effects on the transmission of Gaussian beams by anisotropic parallel plates
Influence of the plate surfaces roughness in precise ellipsometry experiments
is studied. The realistic case of a Gaussian laser beam crossing a uniaxial
platelet is considered. Expression for the transmittance is determined using
the first order perturbation theory. In this frame, it is shown that
interference takes place between the specular transmitted beam and the
scattered field. This effect is due to the angular distribution of the Gaussian
beam and is of first order in the roughness over wavelength ratio. As an
application, a numerical simulation of the effects of quartz roughness surfaces
at normal incidence is provided. The interference term is found to be strongly
connected to the random nature of the surface roughness.Comment: 18 pages, Journal of Physics D: Applied Physics, volume 36, issue 21,
pages 2697 - 270
Risk factors associated with mastitis and raw milk quality in small farms of Texcoco, México
The consumption of raw milk or its use in the production of dairy products, increases the risk of transmission of diseases, caused by pathogenic organisms or toxins, which affect the quality and safety of milk, as a result of poor milking practices or improper handling of the product. The objective of the study was to determine the nutritional and physicochemical quality, the presence of aflatoxins in raw milk, as well as risk factors for mastitis, in 20 family farms in the Texcoco region of Mexico. MilkoScan FT1 was used for physicochemical and nutritional analysis of milk and somatic cells and cow health were quantified using the Somaticell test; in addition, the presence of Aflatoxin M1 was determined by lateral flow immuno-chromatogenetics. The results showed normal nutritional values of milk according to NMX-F-700-COFOCALEC-2012, which assure its quality for human. The pH varied from 5.0 - 8.4, indicating poor control of milk temperature on some farms, causing acidity problems. Logistic analysis showed that a good cleaning of the udder in the milking prevents it to be a risk factor for the increase of somatic cells and degree of mastitis, not so the type of milking and sealing of udders. The Somaticell technique®, allowed a quantitative and efficient diagnosis of clinical mastitis and no presence of aflatoxin AFM1 was found in raw milk, which ensures that there is no problem for the consumption of the product or its transformation into products Dairy.Objective: to determine the nutritional and physicochemical quality, and the presenceof aflatoxins in raw milk, as well as risk factors for developing mastitis in 20 family farmsin the region of Texcoco, Mexico.Methods: MilkoSCan FT1 was used for nutritional and physicochemical analysis ofmilk. Somatic cells were quantified and the cow’s health status was tested usingSomaticell; furthermore, the presence of Aflatoxin M1 was determined using lateral flowimmunochromatography.Results: the milk evaluated in this study reported normal nutritional values according toNMX-F-700-COFOCALEC-2012, which guarantees its quality for human consumption.The pH ranged from 5.0 to 8.4, which indicates deficient temperature control in somefarms, leading to problems with acidity. The logistical analysis showed that adequateudder cleaning during milking is important to avoid it being a risk factor for an increasein somatic cells and degree of mastitis, although not the milking technique or teatsealing. The presence of aflatoxin AFM1 was not reported in raw milk.Study implications: the Somaticell® technique renders a qualitative and efficientdiagnosis of clinical mastitis.
Conclusions: raw milk quality from this region guarantees consumers with a safe andapt product for human consumption or transformation into dairy byproducts
The low level of debris disk activity at the time of the Late Heavy Bombardment: a Spitzer study of Praesepe
We present 24 micron photometry of the intermediate-age open cluster
Praesepe. We assemble a catalog of 193 probable cluster members that are
detected in optical databases, the Two Micron All Sky Survey (2MASS), and at 24
micron, within an area of ~ 2.47 square degrees. Mid-IR excesses indicating
debris disks are found for one early-type and for three solar-type stars.
Corrections for sampling statistics yield a 24 micron excess fraction (debris
disk fraction) of 6.5 +- 4.1% for luminous and 1.9 +- 1.2% for solar-type
stars. The incidence of excesses is in agreement with the decay trend of debris
disks as a function of age observed for other cluster and field stars. The
values also agree with those for older stars, indicating that debris generation
in the zones that emit at 24 micron falls to the older 1-10 Gyr field star
sample value by roughly 750 Myr.
We discuss our results in the context of previous observations of excess
fractions for early- and solar-type stars. We show that solar-type stars lose
their debris disk 24 micron excesses on a shorter timescale than early-type
stars. Simplistic Monte Carlo models suggest that, during the first Gyr of
their evolution, up to 15-30% of solar-type stars might undergo an orbital
realignment of giant planets such as the one thought to have led to the Late
Heavy Bombardment, if the length of the bombardment episode is similar to the
one thought to have happened in our Solar System.
In the Appendix, we determine the cluster's parameters via boostrap Monte
Carlo isochrone fitting, yielding an age of 757 Myr (+- 36 Myr at 1 sigma
confidence) and a distance of 179 pc (+- 2 pc at 1 sigma confidence), not
allowing for systematic errors.Comment: 22 pages, 14 figures, 9 tables, emulateapj format; Accepted for
publication in The Astrophysical Journa
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