Electronic Commerce, Consumer Search and Retailing Cost Reduction

This paper explains four things in a unified way. First, how e-commerce can generate price equilibria where physical shops either compete with virtual shops for consumers with Internet access, or alternatively, sell only to consumers with no Internet access. Second, how these price equilibria might involve price dispersion on-line. Third, why prices may be higher on-line. Fourth, why established firms can, but need not, be more reluctant than newly created firm to adopt e-commerce. For this purpose we develop a model where e-commerce reduces consumers' search costs, involves trade-offs for consumers, and reduces retailing costs.Comment: 29th TPRC Conference, 200

Using Ontologies for the Design of Data Warehouses

Obtaining an implementation of a data warehouse is a complex task that forces designers to acquire wide knowledge of the domain, thus requiring a high level of expertise and becoming it a prone-to-fail task. Based on our experience, we have detected a set of situations we have faced up with in real-world projects in which we believe that the use of ontologies will improve several aspects of the design of data warehouses. The aim of this article is to describe several shortcomings of current data warehouse design approaches and discuss the benefit of using ontologies to overcome them. This work is a starting point for discussing the convenience of using ontologies in data warehouse design.Comment: 15 pages, 2 figure

Electronic commerce, consumer search and reailing cost reduction

This paper explains four things in a unified way. First, how e-commerce can generate price equilibria, where physical shops either compete with virtual hops for consumers with Internet access, or alternatively, sell only to consumers with no Internet access. Second, how these price equilibria might involve price dispersion on-line. Third, why prices may be higher on-line. Fourth, why established firms can, but need not, be more reluctant than newly created firms to adopt ecommerce. For this purpose we develop a model where e-commerce reduces consumers’ search costs, involves trade-offs for consumers, and reduces retailing costs. Este trabajo explica, de manera unificada, cuatro cosas. Primero, cómo el comercio electrónico puede generar equilibrios de precios en los que las tiendas físicas compiten con las tiendas virtuales por los consumidores con acceso a Internet, o, alternativamente, venden sólo a los clientes que no tienen acceso a Internet. Segundo, cómo estos equilibrios de precios pueden generar dispersión de precios en Internet. Tercero, por qué los precios de las tiendas virtuales pueden ser más altos que los de las tiendas físicas. Y cuarto, por qué las empresas establecidas pueden tener menos incentivos que las empresas de nuevas creación para abrir tiendas virtuales. Para ello desarrollamos un modelo en el que el comercio electrónic o reduce los costes de búsqueda de los consumidores, implica un trade-off para los consumidores, y disminuye los costes de producción de las empresas.Electronic-Commerce, Search, Cost Reduction, Retailing

ELECTRONIC COMMERCE, CONSUMER SEARCH AND RETAILING COST REDUCTION

This paper explains three things in a unified way. First, how e-commerce can generate price equilibria, where physical shops either compete with virtual shops for consumers with Internet access, or alternatively, sell only to consumers with no Internet access. Second, how these price equilibria might involve price dispersion on-line. Third, why prices may be higher on-line. For this purpose we develop a model where e-commerce: reduces consumers’ search costs, involves trade-offs for consumers, and reduces retailing costs.

Aircraft clouds: from chemtrail pseudoscience to the science of contrails

The most frequent statements and arguments found in pseudoscience websites and forums supporting the existence of so-called aircraft chemtrails can be refuted with a scientific explanation of the processes resulting in the formation of condensation or deposition trails, known as contrails. Thus, the hypothesis that chemtrails exist is disproven by the scientific literature that shows that they are the exact same entity as contrails: They are hydrological phenomena which result from a physical process referenced in the many studies carried out since the beginning of the age of aviation, in the early twentieth century. Hence, in this paper we conclude that pseudoscience’s chemtrails are nothing more than the contrails described by science.Peer ReviewedVersió final publicad

Taking shortcuts to measure species diversity: parasitoid Hymenoptera subfamilies as surrogates of species richness

When trying to assess entomological diversity, identifying taxa at levels higher than species is much easier and may provide a wider vision of other ecological features. In this work, we used the data from several samplings made in across six cacao farms in Mérida state (Venezuela). Farms fell into two categories according to intensity of perturbation. In these samplings we identified all parasitoid Hymenoptera families. All individuals belonging to families Ichneumonidae, Braconidae and Chalcididae were sorted to subfamilies and then to morphospecies. The accuracy of subfamilies richness to predict the species richness and to detect differences in the conservation status of plantations was tested. The species aggregation according to the sampling size was also explored. The three families this study was focused on represented 23 % of the total sampling, comprising 40 subfamilies and 393 morphospecies. Results showed a significant high positive correlation between subfamilies and species richness, and species/subfamilies ratio was about 4.5:1, with logarithmic relationship with sampling size tending to stabilisation at sizes greater than 15 individuals per sampling day. Subfamily richness detected the nearly-significant differences in plantations with the same accuracy as species richness, and therefore surrogacy effectiveness of parasitoid Hymenoptera subfamilies richness may be accepted for cacao plantations.This research was supported by Fundacite-Mérida, within the project Red Socialista de Innovación Productiva (RSIP) en Cacao del Municipio Obispo Ramos de Lora, funded by the Ministerio del Poder Popular para Educación Universitaria, Ciencia y Tecnología of Gobierno Bolivariano de Venezuela

The potential of the sea breeze for wind energy generation in peri-urban coastal areas using small wind turbines

This work investigates the potential of the sea breeze for wind energy generation with small wind turbines. For this purpose, we used wind data recorded in the Llobregat Delta (NE of the Iberian Peninsula) from 1993 to 2010 and turbine power curves obtained from QBlade, FAST and AeroDyn freeware tools, and from the manufacturer. The HP-600W turbine, with hub-height 8 m, would deliver 126 kWh in a year (53 kWh during the sea breeze period, i.e., March 1 to September 30, 10 to 19h LT), with average power of 14 W (27 W). The results for the entire year agree with data measured in situ in 2015, but it is not the case for the sea breeze period. Therefore, more research is necessary to validate completely the proposed approach, and to confirm the real potential of the sea breeze for micro-generation in a peri-urban coastal area like the one under study, where large wind farms are not feasible.Peer ReviewedPostprint (author's final draft

Orígenes y desarrollo turístico en Alicante: del veraneo al turismo de masas

Estudio de lo orígenes de la actividad turística en Alicante, a partir del último tercio del siglo XIX hasta la llegada del turismo de masas y el desarrollo y evolución de Benidorm de la mano de su inventor, el alcalde Pedro Zaragoza Orts

Development of a Low-Cost Weather Station to Measure in Situ Essential Climate Variables

A weather station is proposed especially designed for developing countries, and to meet the standards of the international scientific community making research on the earth system. The station would measure in situ several ECV (essential climate variables). These data may enable an agricultural breakthrough in countries lacking meteorological infrastructure, help in climate change monitoring, and facilitate diffusion of wind energy. A pre-feasibility analysis is presented. It appears interesting that the station is supplied by a social enterprise. A research to establish the best shelter design using computational fluid dynamics is also reported. The criterion is the accuracy with which the surface air temperature is reproduced inside the shelter. A design following recommendations by the WMO (World Meteorological Organization), a smaller design with identical geometry, and two alternative small designs are analyzed. All four designs are simulated in PVC, natural rubber and wood, with and without white paint coating. The smaller shelters perform better. The influence of the material, dimensions and design is smaller than that of the white paint. Shelters made of PVC or rubber, and/or in alternative designs, may be more interesting if other criteria are considered, like whether logistics, manufacturing, etc. are more sustainable, easier and/or cheaper.Peer ReviewedPostprint (published version