Mapeo de los niveles de Radón 222 en el distrito de San Martín de Porres (Lima-Perú) en el periodo 2015-2016

El objetivo de este trabajo es determinar los niveles de Radón 222 y su progenie en interiores en el distrito de San Martín de Porres durante cinco periodos en los a~nos 2015-2016. Las mediciones se realizaron usando detectores pasivos de huellas nucleares de nitrato de celulosa (LR-115 tipo 2). Las mediciones se realizaron al interior de viviendas considerando diferentes parámetros como el material de construcción, edad de la vivienda, tipo de suelo entre otros, colocando dos detectores en diferentes ambientes de las viviendas. Para la adquisición de imágenes luego de haber sometido a los detectores a un tratamiento químico que revela las huellas latentes, se empleó el software V.4.0 del microscopio óptico marca Leica, que permite una mejor calidad en cuanto a la adquisición de imágenes. Para realizar el conteo de las huellas nucleares en los detectores luego de haber adquirido las imágenes mediante el microscopio se uso el software ImageJ, para el cual se implementó un macro que permite automatizar el proceso de conteo. Finalmente con los 125 puntos de medición se reportan valores promedio por vivienda en el rango de 103,0 Bq=m3 hasta los 218,9 Bq=m3, con los cual se ha elaborado el primer mapeo para el distrito de San Martín de Porres en el cual se muestra los variaciones de los niveles de concentraciones de Radón 222 ambiental y su progenie. Además se determinó que existe un 7,6% de probabilidad de superar el nivel de referencia de 200 Bq=m3 establecido por el IPEN.Tesi

Riesgo radiológico debido a la radiactividad natural y exhalación de radón de suelos y materiales de construcción peruanos

La exposición al Radón es una preocupación importante debido a su papel en el aumento del riesgo de cáncer de pulmón. Para evaluar el riesgo de exposición, es necesario realizar mediciones de Radón en el aire interior de los hogares, y tener caracterizado el riesgo radiológico debido a los materiales de construcción y tomar medidas de prevención si es necesario. La exhalación de Radón en materiales de construcción se midió empleando el método de acumulación en una cámara cerrada durante un período de 24 horas para muestra disgregada o pulverizada y de 28 días para material compacto. La concentración de Radón en la cámara se mide regularmente durante este período y se utiliza para calcular la tasa de exhalación en masa y en superficie respectivamente. En el caso de suelos, el riesgo radiológico está asociado con la permeabilidad la concentración de Radón en el suelo. La medición de estos parámetros permitió determinar el potencial geogénico de Radón. Los resultados de este estudio muestran que la exhalación de 222Rn en materiales de construcción y suelos puede variar significativamente. En materiales de construcción, se encontró una tasa de exhalación promedio de 14.01 ± 1.04 mBq kg−1 h −1 , con un rango de [4.50 ± 0.42] a [22.34 ± 1.30] mBq kg−1 h −1 . Además, se encontró una buena correlación entre la concentración total de Radio en los materiales de construcción y la tasa de exhalación de Radón, con un coeficiente de correlación R2 de 0.88. Los dos tipos de ladrillo mostraron las tasas de exhalación más altas, posiblemente debido a la cercanía de la zona de extracción de materia prima para su elaboración con regiones con una alta probabilidad de presentar uranio. Por otro lado, las muestras de yeso no mostraron exhalación significativa de 222Rn, lo que concuerda con la cantidad de Radio en estas muestras. Finalmente, los resultados obtenidos de índices radiológicos de todos los tipos de muestras son importantes ya que demuestran que los materiales de construcción estudiados no representan un riesgo para la salud al usarlos en la construcción de viviendas.Radon exposure is a major concern due to its role in increasing the risk of lung cancer. To assess radiation exposure risks, measuring radon levels indoor air and characterizing the radiological hazard due to building materials is necessary. The radon exhalation rate in building materials was measured by closed-chamber accumulation over 24 h for dissociated or pulverized samples and 28 days for compacted materials. The Radon concentration in the chamber is measured regularly during this period and is used to calculate the Radon mass exhalation rate and Radon surface exhalation rate, respectively. In the case of soils, the radiological risk is associated with the geogenic potential of Radon. This parameter is obtained from the permeability and the concentration of Radon in the ground. The results of this study show that the radon exhalation rate in building materials and soils can vary significantly. In building materials, an average exhalation rate of 14.01 ± 1.04 mBq kg−1h −1 was found, with a range of [4.50 ± 0.42] to [22.34 ± 1.30] mBq kg−1 h −1 . In addition, a good correlation was found between the total Radium concentration in building materials and the Radon exhalation rate, with a correlation coefficient (R2 0.88). The radon exhalation rate in bricks is higher than in other samples. It can be because the area of raw material extraction for the elaboration of bricks is the closest to the uranium-producing possible regions. Gypsum samples did not show significant radon exhalation, which is consistent with the amount of radium in these samples. Finally, the results obtained for radiological indexes (Radium equivalent Raeq, Gamma index Iγ, and External hazard Hex) all types of samples are suitable for use as building materials because they present a low activity concentration

Monitoreo de los niveles de Radón 222 en el distrito de San Miguel - Lima en el periodo 2016-2017

El presente trabajo tiene por objetivo estimar los niveles de Radón 222 las viviendas en el distrito de San Miguel entre los años 2016-2017. En el estudio se tomó en consideración diferentes parámetros como el material de construcción, edad de la vivienda, tipo de suelo, entre otros, con el fin de encontrar una relación entre la concentración de radón y estos parámetros. Las mediciones se realizaron siguiendo la Metodología de Detectores de Trazas Nucleares, y el detector empleado fue el LR-115 tipo II (con una capa activa de nitrato de celulosa de 12 micrómetros y capaz de registrar partículas alfas en el rango de 1 - 5.6 MeV), detector pasivo de trazas nucleares. El monitoreo realizado en San Miguel forma parte de un proyecto realizado en Lima Metropolitana con el objetivo de elaborar el primer mapa de radón. Se estima que la concentración promedio de radón en el distrito de San Miguel es 160 Bq/m3 . Con un total de 34 puntos de medición se elaboró el mapa de radón para San Miguel. Además, existe un 26,5% de probabilidad de sobrepasar el umbral de referencia de 200 Bq/m3 establecido por el IPEN

Clima organizacional y desempeño docente en una institución educativa de Sartimbamba, Región La Libertad - 2019

El presente trabajo de investigación tuvo como objetivo principal determinar la relación entre clima organizacional y desempeño docente en la I.E. N° 80149 Marcabal Grande, Distrito de Sartimbamba, Provincia Sánchez Carrión, Región La Libertad, en el año 2019. El tipo de diseño de investigación fue descriptivo-correlacional, se utilizó el método hipotético-deductivo. La población objeto de estudio estuvo conformado por 17 individuos siendo la totalidad de docentes de los tres niveles de la I.E. Marcabal Grande. Los instrumentos utilizados para recoger información fueron un cuestionario de clima organizacional (28 ítems) y una ficha de evaluación en el Marco del Buen Desempeño Docente (20 ítems). Ambos instrumentos fueron validados por juicio de expertos y por la aplicación de una prueba piloto obteniéndose un valor de 0,878 y 0,881 respectivamente. Aplicados los instrumentos, el análisis de datos puso de manifiesto que existe una correlación positiva alta (0.656) entre clima organizacional y el desempeño docente en la I.E. N° 80149 Marcabal Grande. Es decir, que a mayores niveles de clima organizacional existirán mayores niveles de Desempeño docente.Tesi

e-RetailTest: Scale to Assess the Attitude of Consumers towards E-Commerce in the Retail Sector

Changes in consumer behavior are driven by tastes and preferences that change over time as their socioeconomic conditions change. The objective of this study was to validate the psychometric characteristics of the e-RetailTest scale, created to measure consumer attitudes towards online shopping in developing countries, particularly in the Peruvian market. The e-RetailTest evaluates five variables present in the online purchase process: (a) quality of web design, (b) risk when making a purchase, (c) customer service, (d) security and (e) satisfaction, with a total of twenty items using a Likert scale. A total of 422 valid responses were collected from Peruvian consumers who had had online shopping experience in the retail sector. Statistically, we worked with the AFE exploratory factor analysis and the AFC confirmatory factor analysis. The results suggest that this first version of the e-RetailTest presents adequate psychometric evidence to measure the attitude of consumers towards online purchases in the retail sector in the Peruvian market. Thus, it seeks to contribute to the advancement of the study of these important variables of Latin American consumer behavior

e-RetailTest: Scale to Assess the Attitude of Consumers towards E-Commerce in the Retail Sector

Changes in consumer behavior are driven by tastes and preferences that change over time as their socioeconomic conditions change. The objective of this study was to validate the psychometric characteristics of the e-RetailTest scale, created to measure consumer attitudes towards online shopping in developing countries, particularly in the Peruvian market. The e-RetailTest evaluates five variables present in the online purchase process: (a) quality of web design, (b) risk when making a purchase, (c) customer service, (d) security and (e) satisfaction, with a total of twenty items using a Likert scale. A total of 422 valid responses were collected from Peruvian consumers who had had online shopping experience in the retail sector. Statistically, we worked with the AFE exploratory factor analysis and the AFC confirmatory factor analysis. The results suggest that this first version of the e-RetailTest presents adequate psychometric evidence to measure the attitude of consumers towards online purchases in the retail sector in the Peruvian market. Thus, it seeks to contribute to the advancement of the study of these important variables of Latin American consumer behavior

Estimation of Indoor 222Rn Concentration in Lima, Peru Using LR-115 Nuclear Track Detectors Exposed in Different Modes

Radon is the main source of natural radioactivity, and its measurement is considered extremely important in radioprotection, given its relationship with the occurrence of lung cancer. In the last two years, measurements of this radioactive gas were carried out in Lima considering a grid of 5 km (Formula presented.) and the population density to determine the number of measurements to be carried out. Cellulose nitrate nuclear track detectors exposed in bare mode and diffusion chamber mode were used to estimate (Formula presented.) Rn concentrations. In diffusion chamber mode, non-commercial monitors and commercial monitors were used. The monitoring results are presented for 43 districts of the Lima Province whose population is approximately ten million inhabitants occupying a total area of 2655.15 km (Formula presented.). Measurements were made obtaining an average concentration of 49 Bq·m (Formula presented.) using bare detectors and 66 Bq·m (Formula presented.) using non-commercial diffusion chambers. Average concentrations obtained by both detector exposure modes were below the maximum concentration recommended by the WHO. A radon ((Formula presented.) Rn) map was also obtained as a visual representation of the (Formula presented.) Rn levels in the Lima province using inverse distance weighting (IDW) interpolation

Varejo Online e Varejo Físico: o Caso Nicoboco

The main objective of this study was to identify the differences and similarities of the retail marketing mix. The object examined are the businesses which have physical and online stores, looking for the generic strategies, competitive advantage, target market and positioning. It has been chosen the exploratory qualitative research, via the case study method. The sources of evidence adopted in this study were direct observation in the physical and virtual stores of the Nicoboco company and an in-depth interview with the general manager of the stores, following a semi structured script. From an analysis of these sources it was identified that the company adopts different strategies in the retail marketing mix. For this reason, there may be benefits in the traditional store, for those customers who prefer to touch the product and try it and also for the consumers who do not have access to the physical store and shop by a virtual connection. Therefore, it was understood that companies which sell products in physical and online stores have a competitive advantage over against those who act in only one of them, because they reach a wider audience.O objetivo do estudo foi identificar as diferenças e semelhanças do composto de marketing no segmento de varejo, conhecido também como composto varejista. O olhar recai sobre os negócios com lojas físicas e virtuais, explorando as estratégias genéricas, vantagem competitiva, mercado alvo e posicionamento. Optou-se pela pesquisa exploratória qualitativa, por meio do método de estudo de caso. A partir da análise das fontes de evidência, identificou-se que a empresa adota estratégias distintas no composto de varejo. Por esse motivo, pode haver benefícios na loja tradicional, para aqueles clientes que preferem uma experiência tátil com o produto e, no âmbito virtual, para os consumidores que não têm acesso à loja física. Portanto, compreendeu-se que as empresas que vendem produtos em lojas físicas e on-line acabam tendo uma vantagem competitiva perante aquelas que atuam em apenas uma delas, por poderem atingir um público maior

Symptom cluster analysis of long COVID-19 in patients discharged from the Temporary COVID-19 Hospital in Mexico City.

INTRODUCTION: Several reports have emerged describing the long-term consequences of COVID-19 and its effects on multiple systems. METHODS: As further research is needed, we conducted a longitudinal observational study to report the prevalence and associated risk factors of the long-term health consequences of COVID-19 by symptom clusters in patients discharged from the Temporary COVID-19 Hospital (TCH) in Mexico City. Self-reported clinical symptom data were collected via telephone calls over 90 days post-discharge. Among 4670 patients, we identified 45 symptoms across eight symptom clusters (neurological; mood disorders; systemic; respiratory; musculoskeletal; ear, nose, and throat; dermatological; and gastrointestinal). RESULTS: We observed that the neurological, dermatological, and mood disorder symptom clusters persisted in >30% of patients at 90 days post-discharge. Although most symptoms decreased in frequency between day 30 and 90, alopecia and the dermatological symptom cluster significantly increased (p < 0.00001). Women were more prone than men to develop long-term symptoms, and invasive mechanical ventilation also increased the frequency of symptoms at 30 days post-discharge. CONCLUSION: Overall, we observed that symptoms often persisted regardless of disease severity. We hope these findings will help promote public health strategies that ensure equity in the access to solutions focused on the long-term consequences of COVID-19

The Magnitude of Global Marine Species Diversity

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000–72,000 species are collected but not yet described, and that 482,000–741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7–1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century