ABSTRACT
We develop a general optical model and describe the absolute radiometric calibration of the readings provided by two widely-used night sky brightness sensors based on irradiance-to-frequency conversion. The calibration involves the precise determination of the overall spectral sensitivity of the devices and also the constant G relating the output frequency of the light-to-frequency converter chip to the actual band-weighted and field-of-view averaged spectral radiance incident on the detector (brightness). From these parameters, we show how to define a rigorous astronomical absolute photometric system in which the sensor measurements can be reported in units of magnitudes per square arcsecond with precise physical meaning.
ABSTRACT
Night-time lights interact with human physiology through different pathways starting at the retinal layers of the eye; from the signals provided by the rods; the S-, L- and M-cones; and the intrinsically photosensitive retinal ganglion cells (ipRGC). These individual photic channels combine in complex ways to modulate important physiological processes, among them the daily entrainment of the neural master oscillator that regulates circadian rhythms. Evaluating the relative excitation of each type of photoreceptor generally requires full knowledge of the spectral power distribution of the incoming light, information that is not easily available in many practical applications. One such instance is wide area sensing of public outdoor lighting; present-day radiometers onboard Earth-orbiting platforms with sufficient nighttime sensitivity are generally panchromatic and lack the required spectral discrimination capacity. In this paper, we show that RGB imagery acquired with off-the-shelf digital single-lens reflex cameras (DSLR) can be a useful tool to evaluate, with reasonable accuracy and high angular resolution, the photoreceptoral inputs associated with a wide range of lamp technologies. The method is based on linear regressions of these inputs against optimum combinations of the associated R, G, and B signals, built for a large set of artificial light sources by means of synthetic photometry. Given the widespread use of RGB imaging devices, this approach is expected to facilitate the monitoring of the physiological effects of light pollution, from ground and space alike, using standard imaging technology.
ABSTRACT
El presente documento tiene el propósito de proporcionar información sobre el número de parteras tradicionales que existen en la ciudad de Potosí, los conocimientos y actitudes sobre el trabajo de parto que tienen estas personas además de identificar a las parteras tradicionales con el fin de proporcionar cursos sobre la atención del parto limpio
Subject(s)
Censuses , Midwifery , BoliviaABSTRACT
Se presenta una experiencia de aplicaciòn de la Tabla de Clsificaciòn Ultrasònica de Tumores Ovàricos desarollada por el departamento de Ginecologia y Obstetricia de la Universidad de Tokio Japòn. Se trata de 50 casos de tumores ovàricos diagnosticados o confirmados por ecografia con propòsitos operatorios en la Clinica del Centro Mèdico de Diagnòstico de la ciudad de Potosi, Bolivia. Delos 50 tumores, 22 fueron sometidos a estudios histològicos. Con los patrones ecoicos de la clasificaciòn el indice de negatividad es de 44.0 porciento de 28.0 porciento el de sospecha de malignidad y de 40.0 porciento el de malignidad. Se concluye que la clasificaciòn es ilustrativa y simple, aunque es recomendable la confrontaciòn permanente con la histopatologia y la acumulaciòn de casos para ganar experiencia en el uso de la tabla
