Factores que influyen en la adopción del e-commerce: un caso de estudio para los micronegocios del Área Metropolitana de Monterrey frente a la crisis sanitaria

El objetivo de este artículo es analizar la adopción del comercio electrónico en microempresas, de venta minorista y de servicios del Área Metropolitana de Monterrey (AMM) ante la crisis sanitaria. Basado en el modelo en la conducta de aceptación tecnológica de los microempresarios. Los resultados proporcionaron evidenciar la adopción del comercio electrónico en AMM, por la fuerte relación entre las diferentes características personales y descriptivas de los microempresarios

Factores críticos que determinan la intención de compra en línea en el comercio electrónico mexicano (Critical factors which determine purchase online intent in the Mexican electronic commerce)

Abstract. The following article analyzes the principal factors of electronic commerce that have been explored and studied primarily in developed markets such as the United States and that have been deemed as critical actors in the development and growth of electronic transactions. Specifically, variables and latent factors of this study derive from the models of Technology Acceptance (Davis, 1989) and Diffusion of Innovations (Rogers, 2003). A summary of past empirical studies is provided deriving from the aforementioned theoretical models followed by results of an exploratory field study comprising of 39 valid observations randomly selected from within the Professional Employees Internet Users segment. The methodology used to determine the causal relationship between variables (Betas) was factor analysis (Principal Components) and structural equation modeling, specifically Smart-PLS. The study determined that perceived utility, security and compatibility variables were statistically relevant and significant in determining purchase online intent or the development of electronic commerce in the Professional Employees Internet Users Segment. Resumen. Este artículo analiza los factores del comercio electrónico que han sido explorados y estudiados principalmente en mercados desarrollados (EUA) y que han sido confirmados como críticos en el desarrollo y crecimiento de las transacciones electrónicas. En forma específica, los factores o variables latentes en estudio tienen el sustento y la justificación teórica de los modelos de Aceptación de la Tecnología (Davis, 1989) y la Difusión de las Innovaciones (Rogers, 2003). Se presenta un resumen de los antecedentes de estudios empíricos utilizando estos modelos teóricos. Se reportan los resultados del estudio exploratorio de campo sobre una muestra de 39 observaciones válidas, completas, seleccionadas en forma aleatoria dentro del segmento de usuarios de internet en el sector de empleados profesionistas. La metodología empleada para el análisis y determinación de la relación causal entre las variables (Betas) fue el análisis factorial (componentes principales) y modelación de ecuaciones estructurales, en específico Smart-PLS. El estudio determinó que las variables percepción de utilidad, seguridad y compatibilidad, resultaron ser relevantes y estadísticamente significativas en la determinación de la intención de compra en línea o el desarrollo del comercio electrónico en el segmento de empleados profesionistas en México

Embotelladoras ARCA Uses Operations Research to Improve Territory Design Plans

Embotelladoras ARCA was formed in 2001 by integrating three of the oldest bottlers in Mexico and became the second largest bottler of Coca-Cola products in Latin America. The company distributes its products in the northern region of Mexico and, since 2008, in the north of Argentina and Ecuador. The company have soft-drink sales of more than 1.2 billion unit cases and ranks as the third-largest Coca-Cola bottler in the world. The large size of the market and the relevance of a number of problems faced by the company motivate the use and application of operations research models and techniques One of the most relevant problems the company faces is that of how to segment or partition their customers into clusters or territories to accomodate for a better handling of marketing and distribution decisions. This territory design is not entirely arbitrary since it must satisfy several planning requirements such as territory compactness, territory connectivity, territory balancing, and similarity with existing design. Before 2009, these units were defined by “experience” without quantitative tools giving more weight to the territory compactness criterion. This led to a number of undesirable issues such as highly unbalanced territories, that is, the plans ended up with a large disparity in size with respect to both number of customers and total product sales. This imbalance had a negative effect among company workers since each territory (customer order capturing by sales associates, product routing by truck drivers, and so on) is handled by a different team. In this paper, we apply operations research methods to determine better configurations of the territorial units to ensure that each formed territory is relatively similar in size with respect to both number of customers and total product sales while ensuring some other important planning requirements and maximizing territory compactness. The usage of this methodology has resulted in many important benefits for the company, in particular, it has had a significant improvement with respect to the territory imbalances improving from 30 to 5 %. We highlight some other side benefits resulting from this approach. The company has adopted this proposed tool to make their territory design decisions

Adopción del e-commerce en función de la calidad percibida del servicio, costo y satisfacción en micronegocios del área metropolitana de Monterrey en el periodo 2020-2021 (E-commerce adoption based on perceived service quality, cost, and satisfaction at micro-businesses in the Monterrey metropolitan area in the period 2020-2021)

El propósito principal del artículo es investigar la adopción del e-commerce en la función de la calidad del servicio, costo y satisfacción en las microempresas de los micronegocios del área metropolitana de Monterrey (AMM), Nuevo León México. Para la medición de las variables se aplicó cuestionario de una muestra representativa de 100 microempresarios en cuarto trimestre del 2020 y primero del 2021. Con la información recolectada se realizó modelo de regresión lineal paso a paso. Los resultados obtenidos proveyeron evidencia en cuanto a que la satisfacción es el variable de mayor impacto, siguiendo en importancia la variable costo y en tercer lugar la variable calidad percibida, todas mostraron impacto significativo en la adopción del ecommerc

A Heuristic Approach for a Transportation Problem with Capacity and Time Windows Constraints (Un Enfoque Heurístico para un Problema de Transportación con Restricciones de Capacidad y Ventanas de Horario)

Abstract. We consider a Pickup and Delivery Vehicle Routing Problem (PDP) commonly encountered in real-world logistics operations. The problem involves a set of practical complications that have received little attention in the vehicle routing literature. In this problem, there are multiple vehicle types available to cover a set of pickup and delivery requests, each of which has pickup time windows and delivery time windows. Transportation orders and vehicle types must satisfy a set of compatibility constraints that specify which orders cannot be covered by which vehicle types. In addition we include some dock service capacity constraints as is required on common real world operations. This problem requires to be attended on large scale instances (orders ≥ 500), (vehicles ≥ 150). As a generalization of the traveling salesman problem, clearly this problem is NP-hard. The exact algorithms are too slow for large scale instances. The PDP-TWDS is both a packing problem (assign order to vehicles), and a routing problem (find the best route for each vehicle). We propose to solve the problem in three stages. The first stage constructs initials solutions at aggregate level relaxing some constraints on the original problem. The other two stages imposes time windows and dock service constraints. Our results are favorable finding good quality solutions in relatively short computational times. Keywords. Vehicle Routing, Logistics & Distribution Planning, Scheduling, Time Windows. Resumen. Consideramos un problema de Ruteo para Entrega y Recolección (PDP) el cual es común encontrar en las operaciones Logísticas en el mundo real. El problema involucra un conjunto de consideraciones de tipo práctico que han recibido poca atención en la literatura científica de los problemas de ruteo. En nuestro problema, se presentan múltiples tipos de vehículos los cuales están disponibles para cubrir un conjunto de requerimientos de entrega y de recolección. Cada uno de estos requerimientos debe ser atendido dentro de cierta ventana de horario. Los requerimientos de transporte y los tipos de vehículos deben satisfacer las restricciones de compatibilidad las cuales especifican algunas órdenes que no pueden ser cubiertas por cierto tipo de vehículos. Además se incluyen algunas restricciones relacionadas con la capacidad de andenes disponibles para dar servicio y atención lo cual es común encontrar en las operaciones del mundo real. Nuestro problema requiere ser atendido para instancias de gran tamaño (ordenes ≥ 500) y (vehículos ≥ 150). Este problema considerado tal como una generalización del problema del agente viajero (TSP), debe ser visto claramente como un problema difícil de resolver matemáticamente hablando (NP-Hard). Los algoritmos de solución exacta son demasiado lentos en tiempo como para poder ser utilizados en la solución de instancias de gran tamaño. Nuestro problema PDP-TWDS es al mismo tiempo tanto un problema de empacamiento (para asignar las ordenes de transporte a los vehículos) así como un Daena: International Journal of Good Conscience. 5(2) 45-68. Octubre 2010. ISSN 1870 problema de ruteo (encontrar la mejor ruta para cada vehículo). Nuestra propuesta consiste en resolver el problema en 3 etapas. La primera etapa construye soluciones iniciales a un nivel agregado para lo cual se relajan algunas restricciones del problema original. Las otras dos etapas se encargan de incluir las restricciones de ventana de horario así como de capacidad de andenes para el servicio. Nuestros resultados son muy favorables al encontrar soluciones de alta calidad en tiempos de solución relativamente cortos. Palabras claves. Ruteo de Vehiculos, Logística, Planeación de la Distribución, Programación de Transporte, Ventanas de Horari

Socket shield technique: A systematic review of human studies

Background and Purpose Alveolar bone resorption after dental extraction frequently leads to situations in which long-term function and esthetic success of rehabilitations with dental implants is a challenge. Socket shield has been described as an alternative technique to maintain the alveolar ridge when placing immediate implants. The aim of this review is to evaluate the medium- and long-term clinical outcomes of the socket shield technique in human studies. Material and Methods This review was conducted according to PRISMA guidelines. An electronic search was conducted in four databases: (1) The National Library of Medicine (MEDLINE/PubMed) via Ovid; (2) Web of Science (WOS); (3) SCOPUS; and (4) Cochrane Central Register of Controlled Trials (CENTRAL). The Cochrane Collaboration tool, the Newcastle-Ottawa Quality Assessment Scale and The Joanna Briggs Institute Critical Appraisal tool were used to assess the quality of evidence in the studies reviewed. Results Six articles were included in this review. The studies analysed showed lower rates of horizontal and vertical alveolar bone resorption, better maintenance of the buccal plate, less marginal bone loss and better esthetic results than simple placement of immediate implants. However, a lack of homogeneity was found in evaluation methods of the different outcomes, surgical procedures and prosthetic management. Conclusions Based on the results of this review, it is possible to suggest that socket shield technique could be a good alternative in terms of alveolar bone maintenance, marginal bone stability and aesthetic outcomes in immediate implant treatment. However, it is not possible to recommend this technique as an alternative treatment with the same long-terms predictability as conventional immediate implants

The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and T e-based literature data

Astronomy and Astrophysics 559 (2013): A114 reproduced with permission from Astronomy and AstrophysicsThe use of integral field spectroscopy is since recently allowing to measure the emission line fluxes of an increasingly large number of star-forming galaxies, both locally and at high redshift. Many studies have used these fluxes to derive the gas-phase metallicity of the galaxies by applying the so-called strong-line methods. However, the metallicity indicators that these datasets use were empirically calibrated using few direct abundance data points (Te-based measurements). Furthermore, a precise determination of the prediction intervals of these indicators is commonly lacking in these calibrations. Such limitations might lead to systematic errors in determining the gas-phase metallicity, especially at high redshift, which might have a strong impact on our understanding of the chemical evolution of the Universe. The main goal of this study is to review the most widely used empirical oxygen calibrations, O3N2 and N2, by using newdirect abundance measurements. We pay special attention to (1) the expected uncertainty of these calibrations as a function of the index value or abundance derived and (2) the presence of possible systematic offsets. This is possible thanks to the analysis of the most ambitious compilation of Te-based H ii regions to date. This new dataset compiles the Te-based abundances of 603 H ii regions extracted from the literature but also includes new measurements from the CALIFA survey. Besides providing new and improved empirical calibrations for the gas abundance, we also present a comparison between our revisited calibrations with a total of 3423 additional CALIFA H ii complexes with abundances derived using the ONS calibration from the literature. The combined analysis of T e-based and ONS abundances allows us to derive their most accurate calibration to date for both the O3N2 and N2 single-ratio indicators, in terms of all statistical significance, quality, and coverage of the parameters space. In particular, we infer that these indicators show shallower abundance dependencies and statistically significant offsets compared to others'. The O3N2 and N2 indicators can be empirically applied to derive oxygen abundances calibrations from either direct abundance determinations with random errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a large amount of data), reaching an average precision of 0.08 and 0.09 dex (random) and 0.02 and 0.08 dex (systematic; compared to the direct estimations), respectivelyR.A. Marino is funded by the Spanish program of International Campus of Excellence Moncloa (CEI). D. Mast thank the Plan Nacional de Investigación y Desarrollo funding programs, AYA2012-31935 of the Spanish Ministerio de Economía y Competitividad, for the support given to this project. S.F.S thanks the the Ramón y Cajal project RyC-2011-07590 of the spanish Ministerio de Economía y Competitividad, for the support giving to this project. F.F.R.O. acknowledges the Mexican National Council for Science and Technology (CONACYT) for financial support under the program Estancias Postdoctorales y Sabáticas al Extranjero para la Consolidación de Grupos de Investigación, 2010-2012. We acknowledge financial support for the ESTALLIDOS collaboration by the Spanish Ministerio de Ciencia e Innovación under grant AYA2010- 21887-C04-03. BG-L also acknowledges support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AYA2012- 39408-C02-02. J.F.-B. acknowledges financial support from the Ramón y Cajal Program and grant AYA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as to the DAGAL network from the People’s Program (Marie Curie Actions) of the European Union’s Seventh Framework Program FP7/2007-2013/ under REA grant agreement number PITN-GA-2011-289313. CK has been funded by project AYA2010-21887 from the Spanish PNAYA. P.P. acknowledges support by the Fundação para a Ciência e a Tecnologia (FCT) under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FIS-AST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE). R.M.G.D. and R.G.B. also acknowledge support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AyA2010-15081. V.S., L.G., and A.M.M. acknowledge financial support from the Fundação para a Ciência e a Tecnologia (FCT) under program Ciência 2008 and the research grant PTDC/CTE-AST/112582/200

Seroprevalencia de Trypanosoma cruzi en niños de Veracruz, México: línea de base epidemiológica para un modelo de control fundamentado en la transmisión activa de la enfermedad de Chagas

Introduction. In 2021 the Ministry of Health of Mexico and the Pan American Health Organization launched an initiative to interrupt intra-domiciliary vector transmission of Chagas Disease (CD), based on knowledge of the prevalence of this disease in children. The Mexican State of Veracruz was the leading of this initiative.Objective. To estimate the seroprevalence of Trypanosoma cruzi infection among children under 15 years of age from rural areas of Veracruz, Mexico.Materials and methods. Eight priority localities from the Municipality of Tempoal, Veracruz, were identified for baseline serology. Blood samples were collected on filter paperfrom 817 individuals (June-August 2017) for screening using a third-generation enzyme immunoassay. Reactive cases were confirmed by indirect hemagglutination (HAI), Enzyme linked immunosorbent assay (ELISA), and indirect immunofluorescence (IIF) tests with peripheral blood serum samples. Seroprevalence and its 95% confidence interval (95% C.I.) were calculated.. Results. In the localities Citlaltepetl, Cornizuelo, Cruz de Palma y Rancho Nuevo, CD cases were confirmed in children under 15 years of age with a seroprevalence of 1,9% (95% C.I.: 1,12-3,16%). Conclusions. These results indicate that these communities present recent transmission of CD and allow establishing an epidemiological baseline for the design and implementation of a model based on activities focused on geographic areas with active transmission to advance towards the elimination of intra-domiciliary vector transmission of CD in Mexico.Introducción. En 2021 la Secretaría de Salud de México y la Organización Panamericana de la Salud lanzaron una iniciativa para la interrupción de la transmisión vectorial intradomiciliaria de la enfermedad de Chagas (EC), fundamentada en el conocimiento de la prevalencia de esta enfermedad en población infantil. El estado mexicano de Veracruz fue punta de lanza de esta iniciativa.Objetivo. Estimar la seroprevalencia de infección por Trypanosoma cruzi en menores de 15 años de localidades rurales de Veracruz, México.Materiales y métodos. Se identificaron 8 localidades prioritarias para la serología basal en el municipio de Tempoal, Veracruz. Se colectaron muestra de sangre en papel filtro de 817 individuos (junio-agosto de 2017) para su tamizaje usando un inmunoensayo enzimático de tercera generación. Los casos reactivos del tamizaje se confirmaron mediante pruebas de hemaglutinación indirecta (HAI), ensayo por inmunoabsorción ligado a enzimas (ELISA) e inmunofluorescencia indirecta (IFI) en muestras de suero colectadas en tubo. Se calculó la seroprevalencia y su intervalo de confianza del 95% (I.C. 95%).Resultados. En las localidades Citlaltépetl, Cornizuelo, Cruz de Palma y Rancho Nuevo se confirmaron casos de la EC en menores de 15 años con una seroprevalencia de 1,9% (I.C. 95%: 1,12-3,16%).Conclusiones. Los resultados indican que estas comunidades presentan transmisión reciente de la EC y permiten establecer una línea de base epidemiológica para el diseño e implementación de un modelo fundamentado en acciones dirigidas a áreas geográficas con transmisión activa para avanzar hacia la eliminación de transmisión vectorial intradomiciliar de la EC en México

Izaña Atmospheric Research Center. Activity Report 2019-2020

Editors: Emilio Cuevas, Celia Milford and Oksana Tarasova.[EN]The Izaña Atmospheric Research Center (IARC), which is part of the State Meteorological Agency of Spain (AEMET), is a site of excellence in atmospheric science. It manages four observatories in Tenerife including the high altitude Izaña Atmospheric Observatory. The Izaña Atmospheric Observatory was inaugurated in 1916 and since that date has carried out uninterrupted meteorological and climatological observations, contributing towards a unique 100-year record in 2016. This reports are a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues.[ES]El Centro de Investigación Atmosférica de Izaña (CIAI), que forma parte de la Agencia Estatal de Meteorología de España (AEMET), representa un centro de excelencia en ciencias atmosféricas. Gestiona cuatro observatorios en Tenerife, incluido el Observatorio de Izaña de gran altitud, inaugurado en 1916 y que desde entonces ha realizado observaciones meteorológicas y climatológicas ininterrumpidas y se ha convertido en una estación centenaria de la OMM. Estos informes resumen las múltiples actividades llevadas a cabo por el Centro de Investigación Atmosférica de Izaña. El liderazgo del Centro en materia de investigación y desarrollo con respecto a las técnicas de medición, calibración y validación de última generación, así como la cooperación internacional, le han otorgado una reputación sobresaliente en lo que se refiere al tiempo, el clima, la hidrología y otros temas ambientales afines