379 research outputs found

    Psychological elements explaining the consumer's adoption and use of a website recommendation system: A theoretical framework proposal

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    The purpose of this paper is to understand, with an emphasis on the psychological perspective of the research problem, the consumer's adoption and use of a certain web site recommendation system as well as the main psychological outcomes involved. The approach takes the form of theoretical modelling. Findings: A conceptual model is proposed and discussed. A total of 20 research propositions are theoretically analyzed and justified. Research limitations/implications: The theoretical discussion developed here is not empirically validated. This represents an opportunity for future research. Practical implications: The ideas extracted from the discussion of the conceptual model should be a help for recommendation systems designers and web site managers, so that they may be more aware, when working with such systems, of the psychological process consumers undergo when interacting with them. In this regard, numerous practical reflections and suggestions are presented

    Evaluation of the capabilities of atmospheric pressure chemical ionization source coupled to tandem mass spectrometry for the determination of dioxin-like polychlorobiphenyls in complex-matrix food samples

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    The use of the novel atmospheric pressure chemical ionization (APCI) source for gas chromatography (GC) coupled to triple quadrupole using tandem mass spectrometry (MS/MS) and its potential for the simultaneous determination of the 12 dioxin-like polychlorobiphenyls (DL-PCBs) in complex food and feed matrices has been evaluated. In first place, ionization and fragmentation behavior of DL-PCBs on the APCI source under charge transfer conditions has been studied followed by their fragmentation in the collision cell. Linearity, repeatability and sensitivity have been studied obtaining instrumental limits of detection and quantification of 0.0025 and 0.005 pg µL-1 (2.5 and 5 fg on column) respectively for every DL-PCB. Finally, application to real samples has been carried out and DL-PCB congeners (PCB 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189) have been detected in the different samples in the range of 0.40 to 10000 pg g-1. GC-(APCI)MS/MS has been proved as a suitable alternative to the traditionally accepted confirmation method based on the use of high resolution mass spectrometry and other triple quadrupole tandem mass spectrometry techniques operating with electron ionization. The development of MS/MS methodologies for the analysis of dioxins and DL-PCBs is nowadays particularly important, since this technique was included as a confirmatory method in the present European Union regulations that establish the requirements for the determination of these compounds in food and feed matrices.The authors acknowledge the financial support of Generalitat Valenciana, (research group of excellence PROMETEO/2009/054 and PROMETEO II 2014/023 and Collaborative Research on Environment and Food-Safety (ISIC/2012/016)

    Protected indications of origin as differentiation cue of food products: the Spanish .

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    The "country/region of origin" is a traditionally strategy used by food companies in order to differentiate their production from each other. In Spain, there are more than 140 EU recognised- Designations of Origin comprising several categories of food and drinks. From these, there are only six quality labels on Spanish dry-cured ham. In spite of this lower number of Designations, they suppose almost the 15% of the global economic value. From both a quantitative and a qualitative perspective -based on a SWOT analysis, this paper traits to analyse the role of origin as a marketing differentiation tool. In addition, interesting recommendations are offered in order to enhance the consumer's knowledge of Designations' main characteristics.Differentiation; Protected Designations of Origin, Protected Geographical Indications

    Using response surface methodology to optimize factors in conjoint experiments

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    Identifying relevant attributes or variables is the first objective of conjoint analysis in market research. As a result of technological development, today it is common for researchers to use sequential experimental methods for adjusting design factors in successive phases. In particular, in the field of consumer behaviour these models are used predominantly for assessing subjective perceptions relating to the attributes of different products with high sensorial components (e.g. food, drinks and personal care products) ..

    Propuesta metodológica mediante diseños Box-Behnken para mejorar el rendimiento del análisis conjunto en estudios experimentales de mercado

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    ResumenEl análisis conjunto es una técnica utilizada para estudiar las preferencias de los consumidores en estudios de mercado. Uno de los aspectos más importantes relacionados con el desarrollo de dicha técnica, se centra en fijar el conjunto de elección que deben evaluar los entrevistados. De forma tradicional, se utilizan diseños factoriales para estimar los valores parciales de los factores. Sin embargo, si el investigador, además, está interesado en estimar las interacciones entre dos o más factores, estos diseños requieren un número tan elevado de alternativas que se hace difícil su evaluación, provocando que los entrevistados no utilicen criterios compensatorios. La utilización de diseños Box-Behnken agrupados en bloques permite reducir el esfuerzo cognitivo de los entrevistados y, a la vez, ajustar un modelo de segundo grado. Este trabajo ilustra, mediante un experimento, el uso y las ventajas de utilizar diseños Box-Behnken en estudios de mercado. Los resultados obtenidos muestran el mayor rendimiento de estos modelos en comparación con los diseños factoriales habituales.AbstractConjoint analysis is a technique used to study consumer preferences in market research. One of the most important issues is to determine the choice set which respondents must assess; usually factorial designs to estimate part-worth factors have been used. But, if the researcher is also interested in estimating two or more factor interactions, factorial designs require such a large number of alternatives that makes their evaluation very difficult, leading respondents to not use compensatory criteria. Using Box-Behnken designs in blocks reduce the cognitive effort made by respondents and, at the same time, it allows fitting a quadratic model. This paper illustrates, through an experiment, the properties and how to use Box-Behnken designs in market research. Results showed a better performance of these models when compared with standard factorial designs

    Propuesta metodológica mediante diseños Box-Behnken para mejorar el rendimiento del análisis conjunto en estudios experimentales de mercado

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    El análisis conjunto es una técnica utilizada para estudiar las preferencias de los consumidores en estudios de mercado. Uno de los aspectos más importantes relacionados con el desarrollo de dicha técnica, se centra en fijar el conjunto de elección que deben evaluar los entrevistados. De forma tradicional, se utilizan diseños factoriales para estimar los valores parciales de los factores. Sin embargo, si el investigador, además, está interesado en estimar las interacciones entre dos o más factores, estos diseños requieren un número tan elevado de alternativas que se hace difícil su evaluación, provocando que los entrevistados no utilicen criterios compensatorios. La utilización de diseños Box-Behnken agrupados en bloques permite reducir el esfuerzo cognitivo de los entrevistados y, a la vez, ajustar un modelo de segundo grado. Este trabajo ilustra, mediante un experimento, el uso y las ventajas de utilizar diseños Box-Behnken en estudios de mercado. Los resultados obtenidos muestran el mayor rendimiento de estos modelos en comparación con los diseños factoriales habituales

    Analysis of validamycin as a potential antifungal compound against Candida albicans

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    Validamycin A has been successfully applied in the fight against phytopathogenic fungi. Here, the putative antifungal effect of this pseudooligosaccharide against the prevalent human pathogen Candida albicans was examined. Validamycin A acts as a potent competitive inhibitor of the cell-wall-linked acid trehalase (Atc1p). The estimated MIC50 for the C. albicans parental strain CEY.1 was 500 mg/l. The addition of doses below MIC50 to exponentially growing CEY.1 cells caused a slight reduction in cell growth. A concentration of 1 mg/ml was required to achieve a significant degree of cell killing. The compound was stable as evidenced by the increased reduction of cell growth with increasing incubation time. A homozygous atc1Δ/atc1Δ mutant lacking functional Atc1p activity showed greater resistance to the drug. The antifungal power of validamycin A was limited compared with the drastic lethal action caused by exposure to amphotericin B. The endogenous content of trehalose rose significantly upon validamycin and amphotericin B addition. Neither serum-induced hypha formation nor the level of myceliation recorded in macroscopic colonies were affected by exposure to validamycin A. Our results suggest that, although validamycin A cannot be considered a clinically useful antifungal against C. albicans, its mechanism of action and antifungal properties provide the basis for designing new, clinically interesting, antifungal-related compounds. [Int Microbiol 2013; 16(4):217-225]Keywords: Candida albicans · Rhizoctonia solani · validamycin A · amphotericin B · trehalos

    A Systematic Review of Augmented Reality in Health Sciences: A Guide to Decision-Making in Higher Education

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    The objective of this study was to investigate the usability of the augmented reality (AR) in higher education in the area of health sciences to describe what type of interventions have been developed, their impact on various psychopedagogical aspects of the students as well as the main advantages, disadvantages and challenges in incorporating AR in the teaching-learning process. A systematic review was carried out in the CINAHL, PsycINFO, MEDLINE,Web of Science databases and the Google Scholar search engine. The search was limited to original research articles written in English, Spanish or Portuguese since 2014. The quality of the selected articles (n = 19) was assessed using the Mixed Methods Appraisal Tool (MMAT). The applications and electronic devices used and the measurement instruments used were described. The use of AR made it easier for students to acquire skills, especially in courses with a high component of three-dimensional visualization, and positively influenced various aspects of the learning process such as motivation, satisfaction or autonomous learning. As an educational technological tool applied to higher education in health sciences, AR improves the teaching-learning process by influencing it in a multidimensional wayS
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