Search results for "Trend"
showing 10 items of 404 documents
Tendencia temporal y variaciones geográficas de la prevalencia de síntomas de rinitis alérgica en escolares de 6-7 años de ocho áreas españolas, segú…
2005
Antecedentes: Se presenta la fase III del estudio ISAAC (International Study of Asthma and other Allergies in Childhood) en escolares de 6-7 años de ocho áreas españolas para estimar la tendencia temporal y variaciones geográficas de los síntomas de rinitis alérgica. Material y método: Se comparan las prevalencias de síntomas de rinitis alérgica entre la fase I y fase III, efectuadas entre los años 1993-1994 y 2001-2002, mediante un cuestionario estandarizado y validado según metodología ISAAC, cumplimentado por los padres de los escolares. Participaron ocho centros de Asturias, Barcelona, Bilbao, Cartagena, Castellón, Madrid, Pamplona y Valencia. Se empleó la regresión de Poisson en el aná…
Time trends of technology mediated communication with friends among bullied and not bullied children in four Nordic countries between 2001 and 2010
2016
Background Friends are important in childhood and adolescence, especially to bullied children. Technology mediated communication (TMC) could be used both to develop and maintain friendship. The present study examined (1) trends in the use of TMC with friends between 2001 and 2010; (2) possible differences between bullied and not bullied children and (3) differences between children with few close friends and children with several close friends. Methods Data were obtained from three waves of the serial cross-sectional Health Behaviour in School-Aged Children survey conducted in Denmark, Finland, Iceland and Sweden during 2001/2002, 2005/2006 and 2009/2010. The total sample consisted of 65 95…
Evolución temporal de la prevalencia de síntomas de rinitis alérgica en escolares de 13-14 años de 8 áreas españolas entre 1993-1994 y 2001-2002 segú…
2004
Fundamento y objetivo Estimar la evolucion temporal de la prevalencia de sintomas de rinitis alergica y sus variaciones geograficas. Pacientes y metodo Durante 2001-2002 se efectuo la tercera fase del estudio ISAAC, cuyos resultados se compararon con los de la primera fase (1993-1994). Este estudio transversal incluyo a 30.046 escolares de 13-14 anos en 9 centros (Asturias, Barcelona, Bilbao, Cartagena, Castellon, Madrid, Pamplona, Valencia y Valladolid). Se empleo un cuestionario sobre sintomas de rinitis cumplimentado por los escolares en colegios e institutos con una participacion entre el 100 y el 75,8%. Se emplearon modelos de regresion de Poisson para estudiar la evolucion. Resultados…
Trends over Time in Dental Caries status in Urban and Rural Thai Children.
2017
Background Historically, the prevalence of dental caries was higher in urban areas than rural areas of Thailand. This study aim to examine the time trends in caries status in children in Thailand. Material and Methods Linear regression was used to examine trend of dental caries prevalence and mean number of teeth with caries, filled and missing due to caries (dmft/DMFT) in urban and rural, of 3-, 5-6 and 12-year olds from seven Thailand National Oral Health Surveys conducted approximately every 5 years from 1977 to 2012. Results There were declines in the caries prevalence and mean dmft/DMFT in every age group. Significant results were observed in the mean dmft of 3 year-olds and the mean D…
EFFECTS OF DATA GAP ON THE CAPABILITY TO DETECT TREND IN HYDROCLIMATOLOGICAL TIME SERIES
2012
In the last decades the growing concerns about the existence of global climatic changes push many researchers to use different trend test in order to identify whether monotonic trends exist in hydroclimatological time series such as temperature, precipitation, and streamflow. Unfortunately, these time series often suffer from missing data values mainly due to malfunctioning of gauge for specific time periods. Starting from this premise, the main target of our work is to investigate the effect of data gap in a time series on the results provided by the most used trend test: the nonparametric Mann–Kendall statistical test. Firstly, different synthetic time series characterized by different si…
THE IMPACT OF ELECTION RESULTS ON THE MEMBER NUMBERS OF THE LARGE PARTIES IN BAVARIA AND GERMANY
2005
In this paper, we investigate the relations between the numbers of members of various parties and their results in the elections in Bavaria and in Germany. Deriving from the finding that there is a strong time-delayed correlation between these data-sets for the two largest parties in Bavaria, we show in a simulation based on the Sznajd model that such a correlation leads to very stable majorities, just as in Bavaria.
Expanding Research Capacity at United States Universities: a Study of Academic Research and Development Investment from 1990-2005
2012
Growing emphasis has been placed on universities to contribute to the innovation process and as a result academic research and development expenditures have increased in recent years. Nevertheless, little is known about the specific ways in which universities have expanded their research capacity.This paper examines how universities in the United States (US) have expanded research capacity as research funding has increased. Specifically, it identifies what type of research infrastructure, including various categories of human capital and research equipment, are most closely associated with increased academic research funding. Using data from 375 US universities spanning the period 1990‐2005…
Trend Following with Momentum Versus Moving Average: A Tale of Differences
2018
Despite the ever-growing interest in trend following and a series of publications in academic journals, there is still a great shortage of theoretical results on the properties of trend following rules. Our paper fills this gap by comparing and contrasting the two most popular trend following rules, the Momentum (MOM) and Moving Average (MA) rules, from a theoretical perspective. Our approach is based on the return-based formulation of trading rules and modelling the price trends by an autoregressive return process. We provide theoretical results on the similarity between various trend following rules and the forecast accuracy of trading rules. Our results show that the similarity between t…
Trend
2012
Articolo inserito nel dossier Anni 80 di Doppiozero sulla nozione di trend nelle scienze umane e nel senso comune del periodo.
Estimations comparées de trends logistiques
1980
Référence interne : 80029