Automated Quantitative Analysis of Nerve Fiber Conduction Velocity

poster abstractThe baroreflex (BRX) is essential for reliable autonomic control of arterial blood pressure. Central to BRX function is a rapid, negative feedback control of heart rate. Arterial pressure sensors known as baroreceptors (BR) encode heart rate and blood pressure information into patterns of neural discharge that is conveyed to the central nervous system via a network of sensory afferent nerve fibers. These BR fibers are broadly classified as myelinated A-fibers with diameters in the range of 1-10 μm and unmyelinated Cfibers with diameters typically less than 1 μm. Fiber diameter and conduction velocity are related with the large A-fibers being much faster (> 10 m/sec) than the smaller diameter C-fibers (< 1 m/sec). Recently, our lab has documented an additional phenotype of myelinated BR afferents termed Ah-fibers that are notably present in female; but only rarely observed in male rats. In response to an electrical stimulus, the nerve fibers produce a compound action potential (CAP) that propagates away from the stimulation site. The CAP of each fiber type is observable in the evoked waveform on account of the differing conduction velocities. As Ah-fibers have conduction velocities in the range of 10 m/sec - 2 m/sec, the resulting CAP is clearly separated in time from the faster A-fibers and much slower C-fibers. Root-mean-square analysis of these distinct time segments provides a quantitative measure of the total signal energy from each of the A-, Ah-, and C-type fibers. This project sought to create MATLAB scripts that would import nerve recording files from both male and female rats and automate the energy analysis in an efficient and reliable manner. Doing so not only facilitates the analysis of these large data files, but also reduces the possibility for biases and errors that can occur during a manual measurement of nerve activity

Integrins regulate epithelial cell shape by controlling the architecture and mechanical properties of basal actomyosin networks.

Forces generated by the actomyosin cytoskeleton are key contributors to many morphogenetic processes. The actomyosin cytoskeleton organises in different types of networks depending on intracellular signals and on cell-cell and cell-extracellular matrix (ECM) interactions. However, actomyosin networks are not static and transitions between them have been proposed to drive morphogenesis. Still, little is known about the mechanisms that regulate the dynamics of actomyosin networks during morphogenesis. This work uses the Drosophila follicular epithelium, real-time imaging, laser ablation and quantitative analysis to study the role of integrins on the regulation of basal actomyosin networks organisation and dynamics and the potential contribution of this role to cell shape. We find that elimination of integrins from follicle cells impairs F-actin recruitment to basal medial actomyosin stress fibers. The available F-actin redistributes to the so-called whip-like structures, present at tricellular junctions, and into a new type of actin-rich protrusions that emanate from the basal cortex and project towards the medial region. These F-actin protrusions are dynamic and changes in total protrusion area correlate with periodic cycles of basal myosin accumulation and constriction pulses of the cell membrane. Finally, we find that follicle cells lacking integrin function show increased membrane tension and reduced basal surface. Furthermore, the actin-rich protrusions are responsible for these phenotypes as their elimination in integrin mutant follicle cells rescues both tension and basal surface defects. We thus propose that the role of integrins as regulators of stress fibers plays a key role on controlling epithelial cell shape, as integrin disruption promotes reorganisation into other types of actomyosin networks, in a manner that interferes with proper expansion of epithelial basal surfaces

ICT Use in the Developing World An Analysis of Differences in Computerand Internet Penetration

Computer and Internet use, especially in developing countries, has expanded rapidly in recent years. Even in light of this expansion in technology adoption rates, penetration rates differ markedly between developed and developing countries and across developing countries. To identify the determinants of cross-country disparities in personal computer and Internet penetration, both currently and over time, we examine panel data for 161 countries over the 1999-2004 period. We explore the role of a comprehensive set of economic, demographic, infrastructure, institutional and financial factors in contributing to the global digital divide. We find evidence indicating that income, human capital, the youth dependency ratio, telephone density, legal quality and banking sector development are associated with technology penetration rates. Overall, the factors associated with computer and Internet penetration do not differ substantially between developed and developing countries. Estimates from Blinder-Oaxaca decompositions reveal that the main factors responsible for low rates of technology penetration rates in developing countries are disparities in income, telephone density, legal quality and human capital. In terms of dynamics, our results indicate fairly rapid reversion to long run equilibrium for Internet use, and somewhat slower reversion for computer use, particularly in developed economies. Financial development, either measured as bank lending or the value of stocks traded, is also important to the growth rate of Internet use

Generación del año meteorológico típico para la ciudad de La Plata, Argentina

El presente artículo es el resultado de un trabajo interdisciplinario y se realizó en el marco de las tesis doctorales de Bre (Mecánica Computacional) y García Santa Cruz (Arquitectura). El objetivo es la generación del año meteorológico típico (TMY) para la ciudad de La Plata en Argentina, sobre la base de los datos meteorológicos medidos por el Servicio Meteorológico Nacional (SMN) durante el período 1996-2016 y tiene como antecedentes los trabajos desarrollados por Bre y Fachinotti (2014; 2016) para la generación de los TMY de la ciudad de Santa Fe y de otras 14 localidades de la Región Litoral de Argentina. Se parte de las bases de datos meteorológicas proporcionadas por el SMN que contienen la temperatura de bulbo seco, temperatura de punto de rocío, temperatura de bulbo húmedo, dirección del viento, velocidad del viento, presión, humedad relativa, nubosidad total, altura del techo de nubes, precipitaciones, entre otras, medidas normalmente sobre una base horaria. Debido a que el SMN no cuenta con mediciones de radiación solar, esta variable es generada utilizando el modelo de radiación de Zhang-Huang calibrado para Paraná, localidad con clima Cfa como el de la ciudad de La Plata. Se define el TMY como una concatenación de 12 meses meteorológicos típicos (TMM), siguiendo el clásico método Sandia (Hall y otros, 1978). La tipicidad de un mes dentro de la base de datos se mide utilizando estadística de Finkelstein-Schafer aplicada a nueve índices. Como contribución de este trabajo a la simulación energética de edificios, se convirtió el TMY aquí generado al formato .epw requerido por EnergyPlus.The current article is the result of a interdisciplinary work done in the frameworks of the doctorate thesis of Bre (Computational Mechanics) and García Santa Cruz (Architecture). The goal is to generate the typical meteorological year (TMY) for La Plata city in Argentina, based on weather data measured by the Argentine Meteorological Service (SMN) during the period 1996-2016, and on the previous works of Bre and Fachinotti (2014; 2016) for the generation of TMY for Santa Fe and other 14 locations in the Argentine Littoral Region. The starting point are the weather databases from SMN, containing dry-bulb temperature, dew point temperature, wet-bulb temperature, wind direction and speed, pressure, relative humidity, total sky cover, ceiling height, precipitations, among others, normally measured on a hourly basis. Since SMN does not measure radiation, this variable is obtained using the Zhang-Huang radiation model, as it was calibrated to Paraná city, a location with Cfa climate like La Plata. The TMY is defined as the concatenation of 12 typical meteorological months (TMM), following the classical Sandia method (Hall et al., 1978). The typicality of a month in the database is measured using Finkelstein-Schafer statistics applied to nine daily indices. In order to contribute to building energy simulation, the currently generated TMY was converted to the .epw format required by EnergyPlus.Facultad de Bellas Arte

Generación del año meteorológico típico para la ciudad de La Plata, Argentina

El presente artículo es el resultado de un trabajo interdisciplinario y se realizó en el marco de las tesis doctorales de Bre (Mecánica Computacional) y García Santa Cruz (Arquitectura). El objetivo es la generación del año meteorológico típico (TMY) para la ciudad de La Plata en Argentina, sobre la base de los datos meteorológicos medidos por el Servicio Meteorológico Nacional (SMN) durante el período 1996-2016 y tiene como antecedentes los trabajos desarrollados por Bre y Fachinotti (2014; 2016) para la generación de los TMY de la ciudad de Santa Fe y de otras 14 localidades de la Región Litoral de Argentina. Se parte de las bases de datos meteorológicas proporcionadas por el SMN que contienen la temperatura de bulbo seco, temperatura de punto de rocío, temperatura de bulbo húmedo, dirección del viento, velocidad del viento, presión, humedad relativa, nubosidad total, altura del techo de nubes, precipitaciones, entre otras, medidas normalmente sobre una base horaria. Debido a que el SMN no cuenta con mediciones de radiación solar, esta variable es generada utilizando el modelo de radiación de Zhang-Huang calibrado para Paraná, localidad con clima Cfa como el de la ciudad de La Plata. Se define el TMY como una concatenación de 12 meses meteorológicos típicos (TMM), siguiendo el clásico método Sandia (Hall y otros, 1978). La tipicidad de un mes dentro de la base de datos se mide utilizando estadística de Finkelstein-Schafer aplicada a nueve índices. Como contribución de este trabajo a la simulación energética de edificios, se convirtió el TMY aquí generado al formato .epw requerido por EnergyPlus.The current article is the result of a interdisciplinary work done in the frameworks of the doctorate thesis of Bre (Computational Mechanics) and García Santa Cruz (Architecture). The goal is to generate the typical meteorological year (TMY) for La Plata city in Argentina, based on weather data measured by the Argentine Meteorological Service (SMN) during the period 1996-2016, and on the previous works of Bre and Fachinotti (2014; 2016) for the generation of TMY for Santa Fe and other 14 locations in the Argentine Littoral Region. The starting point are the weather databases from SMN, containing dry-bulb temperature, dew point temperature, wet-bulb temperature, wind direction and speed, pressure, relative humidity, total sky cover, ceiling height, precipitations, among others, normally measured on a hourly basis. Since SMN does not measure radiation, this variable is obtained using the Zhang-Huang radiation model, as it was calibrated to Paraná city, a location with Cfa climate like La Plata. The TMY is defined as the concatenation of 12 typical meteorological months (TMM), following the classical Sandia method (Hall et al., 1978). The typicality of a month in the database is measured using Finkelstein-Schafer statistics applied to nine daily indices. In order to contribute to building energy simulation, the currently generated TMY was converted to the .epw format required by EnergyPlus.Facultad de Bellas Arte

Generación del año meteorológico típico para la ciudad de La Plata, Argentina

El presente artículo es el resultado de un trabajo interdisciplinario y se realizó en el marco de las tesis doctorales de Bre (Mecánica Computacional) y García Santa Cruz (Arquitectura). El objetivo es la generación del año meteorológico típico (TMY) para la ciudad de La Plata en Argentina, sobre la base de los datos meteorológicos medidos por el Servicio Meteorológico Nacional (SMN) durante el período 1996-2016 y tiene como antecedentes los trabajos desarrollados por Bre y Fachinotti (2014; 2016) para la generación de los TMY de la ciudad de Santa Fe y de otras 14 localidades de la Región Litoral de Argentina. Se parte de las bases de datos meteorológicas proporcionadas por el SMN que contienen la temperatura de bulbo seco, temperatura de punto de rocío, temperatura de bulbo húmedo, dirección del viento, velocidad del viento, presión, humedad relativa, nubosidad total, altura del techo de nubes, precipitaciones, entre otras, medidas normalmente sobre una base horaria. Debido a que el SMN no cuenta con mediciones de radiación solar, esta variable es generada utilizando el modelo de radiación de Zhang-Huang calibrado para Paraná, localidad con clima Cfa como el de la ciudad de La Plata. Se define el TMY como una concatenación de 12 meses meteorológicos típicos (TMM), siguiendo el clásico método Sandia (Hall y otros, 1978). La tipicidad de un mes dentro de la base de datos se mide utilizando estadística de Finkelstein-Schafer aplicada a nueve índices. Como contribución de este trabajo a la simulación energética de edificios, se convirtió el TMY aquí generado al formato .epw requerido por EnergyPlus.The current article is the result of a interdisciplinary work done in the frameworks of the doctorate thesis of Bre (Computational Mechanics) and García Santa Cruz (Architecture). The goal is to generate the typical meteorological year (TMY) for La Plata city in Argentina, based on weather data measured by the Argentine Meteorological Service (SMN) during the period 1996-2016, and on the previous works of Bre and Fachinotti (2014; 2016) for the generation of TMY for Santa Fe and other 14 locations in the Argentine Littoral Region. The starting point are the weather databases from SMN, containing dry-bulb temperature, dew point temperature, wet-bulb temperature, wind direction and speed, pressure, relative humidity, total sky cover, ceiling height, precipitations, among others, normally measured on a hourly basis. Since SMN does not measure radiation, this variable is obtained using the Zhang-Huang radiation model, as it was calibrated to Paraná city, a location with Cfa climate like La Plata. The TMY is defined as the concatenation of 12 typical meteorological months (TMM), following the classical Sandia method (Hall et al., 1978). The typicality of a month in the database is measured using Finkelstein-Schafer statistics applied to nine daily indices. In order to contribute to building energy simulation, the currently generated TMY was converted to the .epw format required by EnergyPlus.Facultad de Bellas Arte

PREVALENCE OF ANTIBODIES AGAINST AVIAN PARAMYXOVIRUS TYPE 1 IN BACKYARD TURKEYS IN FOUR PROVINCES OF LIMA, PERU

El objetivo del presente estudio fue determinar la prevalencia de anticuerpos contra Paramixovirus Aviar Tipo 1 (APMV-1) en pavos de crianza familiar (n=388) en cuatro provincias del departamento de Lima (Lima, Huaral, Huaura y Barranca), Perú. Las mues- tras fueron colectadas durante los meses de agosto a diciembre de 2008, y fueron anali- zadas mediante la prueba serológica de Inhibición de la Hemoaglutinación. Se encontró una prevalencia de 3.9%, observándose que 15/388 pavos presentaron títulos de anticuerpos compatibles a un desafío viral con cepas de campo del PMVA-1. La mayor frecuencia de muestras positivas (10/15) se observó en la provincia de Lima, mientras que no se tuvo muestras positivas en la provincia de Barranca. Se concluye que los pavos de crianza familiar de tres provincias de Lima estuvieron expuestos a alguna cepa de PMVA-l, constituyendo un reservorio del virus.The objective of the study was to determine the prevalence of antibodies against avian Paramyxovirus type 1 (APMV-1) in backyard turkeys (n=388) in four provinces of Lima, Peru (Lima, Huaral, Huaura, and Barranca). Blood samples were collected from August to December 2008 and analyzed by hemagglutination inhibition test. The resulting seroprevalence was 3.9% as 15/388 turkeys showed antibody titers consistent with a viral challenge of APMV-1. The highest frequency of positive samples (10/15) was observed in the province of Lima, whereas none sample was positive in the Barranca province. It is concluded that backyard turkeys in three provinces of Lima were exposed to some strains of PMVA-l, constituting a reservoir of virus