On the Influence of the Data Sampling Interval on Computer-Derived K-Indices

The K index was devised by Bartels et al. (1939) to provide an objective monitoring of irregular geomagnetic activity. The K index was then routinely used to monitor the magnetic activity at permanent magnetic observatories as well as at temporary stations. The increasing number of digital and sometimes unmanned observatories and the creation of INTERMAGNET put the question of computer production of K at the centre of the debate. Four algorithms were selected during the Vienna meeting (1991) and endorsed by IAGA for the computer production of K indices. We used one of them (FMI algorithm) to investigate the impact of the geomagnetic data sampling interval on computer produced K values through the comparison of the computer derived K values for the period 2009, January 1st to 2010, May 31st at the Port-aux-Francais magnetic observatory using magnetic data series with different sampling rates (the smaller: 1 second; the larger: 1 minute). The impact is investigated on both 3-hour range values and K indices data series, as a function of the activity level for low and moderate geomagnetic activity

La satisfaction des consommateurs à l’égard des PME de la restauration libre-service : Une étude exploratoire

L’objectif de cet article est, d’une part, de déterminer les dimensions explicatives de la satisfaction des consommateurs des PME oeuvrant dans la restauration et situées dans un contexte particulier qui est celui des aires de restauration au sein des centres commerciaux et, d’autre part, d’analyser leur influence sur la fidélité du consommateur. Une étude quantitative exploratoire a été menée auprès de 766 consommateurs dans deux centres commerciaux de la province de Québec. L’analyse factorielle démontre l’existence de deux dimensions explicatives de la satisfaction : satisfaction à l’égard de l’offre (fraîcheur de la nourriture, sa présentation et la variété de la nourriture, sa qualité) et satisfaction à l’égard de l’environnement du lieu de services. Les résultats obtenus soulignent que la satisfaction globale dépend principalement de la satisfaction envers l’offre. Ils confirment le rôle central et direct de la satisfaction globale sur la fidélité ainsi que son rôle partiellement médiateur dans la relation unissant satisfaction envers l’offre et fidélité. De tels résultats aident ainsi les propriétaires-dirigeants à proposer une meilleure offre aux clients pour les satisfaire et les fidéliser.The main purpose of this article is 1) to determine the variables explaining consumer satisfaction towards shopping centers fast-food restaurants and 2) to analyze the influence of these variables on loyalty. A quantitative exploratory study was conducted with 766 consumers in two shopping centers located in the province of Quebec. Factor analysis demonstrates that two dimensions determine consumer satisfaction : satisfaction towards the offering (freshness, presentation, variety and quality of food) and satisfaction towards the servicescape environment. The results underline that global satisfaction primarily depends on satisfaction towards the offering. The study also confirms the central and direct influence of global satisfaction on loyalty and its moderating effects in the relationship between satisfaction towards the offering and customer loyalty. These results also help SME managers improve their offering in order to better satisfy and retain their customer base.El objetivo de este artículo es 1) determinar las variables explicativas de la satisfacción de los consumidores de PyMEs del sector de la restauración situadas en contextos especiales que es el de las areas de restauración en los centros comerciales y 2) analizar su influencia sobre la fidelidad del consumidor. Un estudio cuantitativo exploratorio ha sido realizado acerca de 766 consumidores en dos centros comerciales de la provincia de Quebec. El análisis factorial demuestra la existencia de dos dimensiones explicativas de satisfacción : la satisfacción frente a la oferta (frescor de la comida, su presentación y la variedad de la comida, su cantidad) y la satisfacción de los alrededores del lugar de servicio. Los resultados obtenidos subrayan que la satisfacción global depende principalmente de la satisfacción de la oferta. Confirman el papel central y directo de la satisfacción global sobre la fidelidad así como su papel como mediador de forma parcial en la relación que une la satisfacción a la oferta y a la fidelidad. Estos resultados ayudan a los propietarios-gerentes a proponer una mejor oferta a los clientes para satisfacerles y fidelizarles

Global disturbance of the transient magnetic field associated to thermospheric storm winds on March 23, 1979

International audienceDuring large magnetic storms, wind disturbances produced by auroral phenomena can affect the whole thermospheric circulation and associated ionospheric dynamo currents for many hours after the end of the storm. This paper presents a morphological analysis of the ground magnetic field disturbance related to the storm winds observed on March 23, 1979, the day after the Coordinated Data Analysis Workshop (CDAW) 6 events. The disturbance in the magnetic field variations is observed on a planetary scale, and its pattern does not correspond to that of the regular field variations related to the undisturbed atmospheric dynamo

Global disturbance of the transient magnetic field associated with thermospheric storm winds on march 23, 1979

Centre National d'Etudes des T•ldcommunications/Centre de Recherche sur la Physique de l'Environnemen

A statistical study of the observed and modeled global thermosphere response to magnetic activity at middle and low latitudes

International audience[1] From one year (2004) of thermosphere total density data inferred from CHAMP/ STAR accelerometer measurements, we calculate the global thermosphere response to auroral magnetic activity forcing at middle and low latitudes using a method based on a singular value decomposition of the satellite data. This method allows separating the large-scale spatial variations in the density, mostly related to altitude/latitude variations and captured by the first singular component, from the time variations, down to timescales on the order of the orbital period, which are captured by the associated projection coefficient. This projection coefficient is used to define a disturbance coefficient that characterizes the global thermospheric density response to auroral forcing. For quiet to moderate magnetic activity levels (Kp < 6), we show that the disturbance coefficient is better correlated with the magnetic am indices than with the magnetic ap indices. The latter index is used in all empirical thermosphere models to quantify the auroral forcing. It is found that the NRLMSISE-00 model correctly estimates the main features of the thermosphere density response to geomagnetic activity, i.e., the morphology of Universal Time variations and the larger relative increase during nighttime than during daytime. However, it statistically underestimates the amplitude of the thermosphere density response by about 50%. This underestimation reaches 200% for specific disturbed periods. It is also found that the difference between daytime and nighttime responses to auroral forcing can statistically be explained by local differences in magnetic activity as described by the longitude sector magnetic indices. Citation: Lathuillère, C., M. Menvielle, A. Marchaudon, and S. Bruinsma (2008), A statistical study of the observed and modeled global thermosphere response to magnetic activity at middle and low latitudes

Social inequalities in breast cancer mortality among French women: disappearing educational disparities from 1968 to 1996

We investigated the time trends in social inequalities in breast cancer mortality with an analysis by age at death and birth cohort using a representative 1% sample of the French population and four subcohorts (1968–1974, 1975–1981, 1982–1988 and 1990–1996). Causes of death were obtained by direct linkage with the French national death registry. Education was measured at the beginning of each period, and educational disparities in breast cancer mortality were studied among women aged 35–74 at the beginning of each period. In the 1970s, higher breast cancer mortality was found among higher educated women. This positive association progressively weakened and no association remained in the 1990s although it disappeared earlier among younger women. In an analysis by birth cohort, the same pattern was found among women born before 1925, whereas no association between education and mortality was observed among women born after 1925. Educational disparities in breast cancer mortality are currently changing and the previously observed positive gradient has disappeared. An important question is whether these relations are indirect, and due to changes in the prevalence of risk factors associated with education, but which we could not study

A Service-based Model for Customer Intelligence in the Age of Big Data

The dominance of the service sector in today’s economy gives prominence to customer intelligence as a means for enterprises to provide optimal service. In fact, the revolution of big data has generated a vast amount of customer data and reshaped the dimensions of science, management, and engineering within enterprises. The big data era also acknowledges the role of customers as value co-creators. Therefore, the objective of this paper is to propose a service-based customer intelligence model, hereafter called SBCI (Service-based Customer Intelligence) model, to guide the development and application of customer intelligence. Laid the groundwork upon the service science, the model is proposed with three levels: i) the network of service systems level for customer value co-creation, ii) the service system level for the science, management, and engineering dimensions, and iii) the service level for customer intelligence services