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Search Results: 1 - 10 of 5516 matches for " Hortencia; Miller "
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Analysis of the Influence of Wind Turbine Noise on Seismic Recordings at Two Wind Parks in Germany  [PDF]
Hortencia Flores Estrella, Michael Korn, Kilian Alberts
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.55006
Abstract: We recorded continuous seismic noise close and around two wind parks with different geological site conditions in order to investigate the effects of wind turbines on seismic signals in the frequency interval between 1 and 10 Hz. In wind park Fraureuth-Beiersdorf (5 turbines, 11 km south from Zwickau, Saxony), we used small seismic networks, with 3 to 5 stations for 1 - 2 weeks. In Heinde (2 turbines, close to Hildesheim, Lower Saxony), we recorded 1 week with one station around 1 km away from the wind turbines and some additional stations for several hours only. With the spectrogram analysis of the data, we clearly identify the diurnal variation on the spectral amplitude separately from the noise generated by the turbines. The turbine noise appears at certain frequency bands around 2.2, 2.7, 3.3, 4.5, 5.2 and 6.6 Hz. A linear relation between the spectral amplitudes of these frequency bands and the wind velocity or rotation velocity of the turbines is clearly identified. The seismic signals produced by the operation of the wind turbines are not peaks at single frequencies, but look more like frequency bands with increased noise amplitudes. They could be identified up to at least 10 km in the case of Fraureuth-Beiersdorf. These bands depend on numerous parameters, i.e. wind turbine height, weight and construction, number of turbines, geology, etc. In both wind parks we also recorded along profiles with increasing distances from the wind turbines. With the analysis of these data, we propose an amplitude attenuation model for the wind park Fraureuth-Beiersdorf to a distance of 9 km, and for Heinde to a distance of 4 km. The attenuation models for both wind parks are quite different, depending probably on the local geology and topography.
Morbilidad infantil por causas respiratorias y su relación con la contaminación atmosférica en Ciudad Juárez, Chihuahua, México
Hernández-Cadena,Leticia; Barraza-Villarreal,Albino; Ramírez-Aguilar,Matiana; Moreno-Macías,Hortencia; Miller,Paul; Carbajal-Arroyo,Luz Aurora; Romieu,Isabelle;
Salud Pública de México , 2007, DOI: 10.1590/S0036-36342007000100005
Abstract: objective: to assess the impact of atmospheric pollutants on the respiratory health of children of different age groups in juarez city, chihuahua, mexico. material and methods: data on emergency room visits between 1997 and 2001 for respiratory diseases in children less than 17 years old were obtained from hospitals in the juarez city belonging to the mexican social security institute (imss). diseases were classified into three groups according to icd 9th and 10th codes: a) upper respiratory diseases, b) lower respiratory diseases, and c) asthma attacks. this information was stratified by age group (<=5 years and >5 years). daily air pollution data (ozone and pm10) and weather conditions were obtained from the monitoring network system in juarez city. statistical analysis was carried out using a generalized additive model assuming a poisson distribution. results: ozone concentrations, but not pm10, were statistically associated with emergency room visits for respiratory diseases, mainly among children 5 years old or younger. in this group, an increase of 20 ppb 1-hr maximum for ozone was associated with an increase of 8.3% in the number of emergency room visits for upper respiratory diseases, with a 3-day exposure lag; and an increase of 12.7% in the number of emergency room visits for lower respiratory diseases when considering a 4-day exposure lag in a maximum 8-hr mobile average. the largest effect for the complete sample and for the group 6 to 16 years of age was observed for 3-day lag (5.1% for an increase of 20 ppb 1-hr maximum for ozone). for the 6 to16 year old group we did not find a significant effect. conclusion: the wide range of risk is quite important and might represent a substantial cost for the health system as well as for the society. our results emphasize the need to implement preventive and control measures for air pollution and avoid the worsening of the present situation.
SPAC: An alternative method to estimate earthquake site effects in Mexico City
Hortencia Flores Estrella,Jorge Aguirre González
Geofísica internacional , 2003,
Abstract: Microtremor recordings are a very useful tool for microzonation studies because of simple data acquisition and analysis. The Spatial Autocorrelation Method (SPAC) proposed by Aki (1957), may be used to constrain the velocity structure underlying the site with microtremor array measurements, and the site effect (dominant period and amplification) can be calculated. In this paper the SPAC method is applied to Ciudad Universitaria, Mexico City. Results are compared with those obtained by Kagawa (1996) with the F-K method. The velocity structure inferred using SPAC method is consistent with Kagawa′s results. We compare the transfer function obtained from the velocity model estimated by SPAC method with the transfer function from Kagawa′s velocity model, and from spectral ratios of earthquake data. We conclude that the velocity structure of a site can be estimated from microtremor recordings by the SPAC method.
The Processing of Pictures and Written Words: A Perceptual and Conceptual Perspective  [PDF]
Paul Miller
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.27109
Abstract: The present study examines similarities and differences in the processing of drawings and their corresponding names. For this purpose, students were asked to determine as fast as possible the identicalness of two pictures as opposed to the identicalness of their written Hebrew names. Twenty-eight Hebrew native speakers from the fifth grade participated in the experiment. Findings suggest that the human information processing system optimizes the processing of information (words, drawings, etc.) according to specific task requirements or task constraints. Stimulus type per se does not seem to determine the depth of its processing, nor does it seem to directly trigger particular modalities of encoding (perceptual, linguistic, semantic). Finally, the findings warrant the conclusion that superiority effects related to the processing of written words and pictorial stimuli reflect artifacts of task requirements rather than inherent characteristics of stimuli.
A Note on a Natural Correspondence of a Determinant and Pfaffian  [PDF]
Gary Miller
Open Journal of Discrete Mathematics (OJDM) , 2017, DOI: 10.4236/ojdm.2016.71001
Abstract: A familiar and natural decomposition of square matrices leads to the construction of a Pfaffian with the same value as the determinant of the square matrix.
New Baetidae (Insecta: Ephemeroptera) Records from Venezuela and Nymph Description of an Unnamed Fallceon Species
Paulo Vilela Cruz,Rafael Boldrini,Carlos F. Quinto,Hortencia Frontado
International Journal of Zoology , 2012, DOI: 10.1155/2012/837092
Abstract: The Ephemeroptera fauna in Venezuela is poorly known, as is also the case in others areas in South America. Recently, two studies increased from 33 to 50 the number of species recorded in Venezuela. The objective of the present study is to report for the first time in Venezuela the following species: Baetodes levis; Camelobaetidius edmundsi; Fallceon sp.; Mayobaetis ellenae. The nymph of Fallceon sp. is described, but is not named because adults were not reared to allow species identification; however, description of this nymph indicates the presence of this genus in South America. 1. Introduction The Ephemeroptera of Venezuela is poorly known [1], it has been characterized as mega-diverse based on studies of the flora and fauna of the Caribbean, Andes, Amazon and Guiana regions [2]. Until 2001, mayfly records for Venezuela represented only about 5% of the nominal mayfly species known in South America [3]. The most recent estimate of species richness indicates Venezuela has about 9% of the mayflies in the Neotropics [4]. The gap in faunal composition reflects the history of collecting rather than the actual richness of this taxon [3]. Based on the number of published studies on mayflies in South America, it is obvious that there has been more collecting effort in Brazil and Argentina than in any other country in this region [3]. In the last decades, a few studies have helped to increase our knowledge of Venezuelan mayflies (e.g., [5–7]). Recently, Nieto et al. [1] and Molineri et al. [4] studied Ephemeroptera in Venezuela’s Guyana Uplands, and in two articles the number of species recorded in the country increased from 33 to 50, reinforcing the need to increase the sampling area in order to really document the Ephemeroptera diversity in this country. The lack of information of this nature makes the analysis of biogeographic patterns difficult and precludes the development of regional identification keys and systematic studies. To improve our knowledge of mayflies of Venezuela, the main objectives of this paper are (1) to report for the first time the following taxa from Venezuela: Baetodes levis Mayo; Camelobaetidius edmundsi Dominique, Thomas & Mathuriau; Fallceon sp. and Mayobaetis ellenae (Mayo) and (2) to describe the nymph of Fallceon sp. 2. Material and Methods Nymphs were collected with an aquatic entomological net and fixed in 80% ethanol. Descriptions were prepared according toHubbard[8] with the aid of DELTA (Description Language for Taxonomy) open software by Dallwitz [9]. Formula for denticles of the mandible incisors has the following
CONFIABILIDAD DE LAS MEDICIONES ANTROPOMéTRICAS EN ESCOLARES DE LA COMUNA DE VICU?A (CHILE)
Alarcón A,María Hortencia; Atalah S,Eduardo;
Revista chilena de nutrición , 2009, DOI: 10.4067/S0717-75182009000400001
Abstract: objective: to analyze the anthropometric technique used by teachers on children from first grade, and to compare those measurements with those taken by a trained professional on the same children. subjects and method: cross-sectional study in lst grade children from 19 municipalized schools and two subsidized particular schools from vicu?a county. an observation guide to register the fulfillment of the methodology recommended by the chilean ministry of health was applied. comparison of the results of the nutritional evaluation (bmi by age and height for age) according to the data of the teacher and the health professional was performed by the kappa index. results: 426 were students studied, 90.6% of the universe. only 27% of the teachers had received qualification and their methodology to weigh and to measure was inadequate in the majority of the cases. the kappa index was inferior to 0.8 and the more frequent errors of classification were underestimation of the low weight (1.9 vs. 3.3%), over-estimation of the overweight (21.1 vs. 18.1%) and obesity (23.0 vs. 20.2%). the agreement was smaller when the used technique was incorrect, in municipalized schools, in the rural area, or when the one in charge to measure was not teacher head (assistant teacher). conclusions: the technique of anthropometric measurement was inadequate in most of the teachers, which determines errors in the nutritional classification. it is necessary more qualification and better instruments to obtain a more reliable data.
CONFIABILIDAD DE LAS MEDICIONES ANTROPOMéTRICAS EN ESCOLARES DE LA COMUNA DE VICU A (CHILE) RELIABILITY OF ANTHROPOMETRIC THE MEASUREMENTS IN STUDENTS FROM VICU A COUNTY (CHILE)
María Hortencia Alarcón A,Eduardo Atalah S
Revista Chilena de Nutricíon , 2009,
Abstract: Objetivo: analizar la técnica antropométrica utilizada por los profesores con los ni os de primero básico y la concordancia del diagnóstico nutricional entre las mediciones realizadas por los profesores y un profesional entrenado. Sujetos y método: estudio transversal en alumnos del Io básico en 19 colegios municipalizados y 2 colegios particulares subvencionados de la Comuna de Vicu a. Aplicación de una pauta de observación sobre el cumplimiento de las normas de medición del Ministerio de Salud. Análisis de concordancia en la evaluación del IMC por edad y talla-edad, según los datos del profesor y del profesional de salud (índice Kappa). Resultados: Se estudiaron 426 escolares, 90,6% del universo. Solo el 27% de los profesores había recibido capacitación y la metodología utilizada para pesar y medir fue inadecuada en la mayoría de los casos. El índice Kappa fue inferior a 0,8 y los errores de clasificación más frecuentes fueron subestimación del bajo peso (1,9 vs 3,3%), sobreestimación del sobrepeso (21,1 vs 18,1%) y de la obesidad (23,0 vs 20,2%). La concordancia fue menor cuando la técnica utilizada era incorrecta, en colegios municipalizados, en sector rural o cuando el encargado de medir no fue el profesor Jefe (unidocente o inspector). Conclusiones: la técnica de medición antropométrica fue inadecuada por la mayor parte de los profesores, lo que determinó errores en la clasificación nutricional. Se requiere más capacitación y mejores instrumentos para obtener una información más confiable. Objective: To analyze the anthropometric technique used by teachers on children from first grade, and to compare those measurements with those taken by a trained professional on the same children. Subjects and Method: Cross-sectional study in lst grade children from 19 municipalized schools and two subsidized particular schools from Vicu a County. An observation guide to register the fulfillment of the methodology recommended by the Chilean Ministry of Health was applied. Comparison of the results of the nutritional evaluation (BMI by age and height for age) according to the data of the teacher and the health professional was performed by the Kappa Index. Results: 426 were students studied, 90.6% of the universe. Only 27% of the teachers had received qualification and their methodology to weigh and to measure was inadequate in the majority of the cases. The Kappa Index was inferior to 0.8 and the more frequent errors of classification were underestimation of the low weight (1.9 vs. 3.3%), over-estimation of the overweight (21.1 vs. 18.1%) and obesity (23.0 vs. 2
NECESIDADES DE TRATAMIENTO PERIODONTAL EN UNA POBLACIóN DE PACIENTES FUMADORES JóVENES
Fuentes Sánchez Jenny Hortencia,Sabogal Rojas Diego
Acta Odontológica Colombiana , 2012,
Abstract:
RESPUESTA SíSMICA EN EL LAGO DE TEXCOCO. RESULTADOS A PARTIR DE REGISTROS DE MOVIMIENTOS FUERTES
Hortencia Flores Estrella,Martín Cárdenas Soto,Cinna Lomnitz
Revista de Ingeniería Sísmica , 2009,
Abstract: En 1995 se instaló un arreglo acelerométrico constituido por seis estaciones en superficie, que formaron dos triángulos con aperturas de 30 y 400 m y un arreglo vertical con instrumentos en cinco profundidades, que alcanzaron los 40 m. La base de datos de este arreglo consta de ocho eventos de movimientos fuertes (5.9 < M < 7.9) que analizamos para obtener la respuesta sísmica, el modelo de velocidades y el espectro de respuesta de sitio. Los resultados de este estudio muestran que la respuesta de sitio está caracterizada por la frecuencia fundamental en 0.37 Hz. El análisis de los registros en pozo permitió obtener un modelo de velocidades que está constituido por dos capas, con factores de atenuación Q distintos para cada una; la amplificación dinámica, debida a las propiedades físicas de las arcillas lacustres, domina la respuesta de sitio. Finalmente, el espectro de respuesta muestra que las seudoaceleraciones máximas en el sitio se encuentran en dos intervalos de periodo: entre 0 y 1 s y entre 2 y 3 s, con ordenadas espectrales de 0.6 g y 0.74 g, respectivamente.
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