SENSOR PARA DETECTAR EL CALOR Y LA POSICIÓN DE OBJETOS MEDIANTE ESTIMULACIÓN TÁCTIL EN PERSONAS INVIDENTES

Este artículo presenta los resultados de un proyecto de investigación desarrollado para alcanzardos objetivos principales: en primera instancia, probar un dispositivo diseñado para que las personasinvidentes localicen objetos e identifiquen sus colores y, en segunda instancia, para caracterizarlas estrategias de orientación activadas por los usuarios cuando utilizan este dispositivo encontraposición a cuando usan un bastón como herramienta principal de orientación.Un grupo de discapacitados visuales utiliza como medio de orientación el bastón, los brazos y lasmanos; el otro utiliza el dispositivo tecnológico diseñado especialmente para esta investigación(Dispositivo Mecatrónico para la Representación Espacial, DMRE).Los datos del trabajo experimental son procesados mediante la metodología de análisis de protocolosverbales. Se estudian los procesos de ubicación espacial de objetos en recintos cerrados y laidentificación de algunos colores (amarillo, rojo, verde y azul) hecha por las personas invidentes queparticiparon. El investigador registra en forma magnética lo que el sujeto expresa en voz alta amedida que resuelve el problema. Se siguió la obra de Ericson y Simon (1993) y la guía metodológicadesarrollada por Maldonado L. F. (2001) para el desarrollo de esta etapa de la investigación.De acuerdo con los resultados, las personas ciegas mientras utilizan el DMRE desarrollan estrategiasde orientación eficientes para la localización de objetos distantes e identificación de su respectivocolor. Estas estrategias son cualitativamente diferentes de las ejecutadas por los invidentescuando utilizan el bastón como herramienta de orientación

Estimation of milk production in hair ewes by two methods of measurement

ABSTRACT Objective. The objective of the current study was to compare two methods to estimate daily milk production in crossbred hair ewes. Materials and methods. Eight multiparous, crossbred (Pelibuey x Katahdin) lactating hair ewes were used in a completely randomized design with repeated measurements, for 56 days. Ewes were fed ad libitum with a diet based on concentrate. Milk production was estimated twice a week for each ewe by both methods, suckled-hand (SH) and weigh-suckle-weigh (WSW) method. Results. Milk production (p>0.05) means were 1031.9±95.6 and 1119.0±95.6 g/day/ewe for SH and WSW method, respectively. Conclusions. No significant differences (p>0.05) were found between methods for milk yield. RESUMEN Objetivo. El objetivo del presente trabajo fue comparar dos métodos para estimar la producción diaria de leche en ovejas de pelo cruzadas. Materiales y métodos. Se utilizaron ocho ovejas multíparas, cruzadas (Pelibuey x Katahdin) y lactantes, en un diseño completamente al azar, con medidas repetidas, durante 56 días. Las ovejas fueron alimentadas ad libitum con una dieta basada en concentrado. La producción de leche se estimó dos veces a la semana a cada oveja, mediante ambos métodos, el doble pesaje del cordero-ordeño manual de la ovejas (DPC-OMO) y el doble pesaje del cordero (DPC). Resultados. La producción de leche estimada (p>0.05) fue de 1031.9±95.6 y 1119.0±95.6 g/día/ovejas para el DPC-OMO y DPC, respectivamente. Conclusión. No se encontraron diferencias significativas (p>0.05) entre métodos de estimación de la producción de leche

MEJORANDO LA CALIDAD DE LAS IMÁGENES OBTENIDAS CON UN DISPOSITIVO DE RETRODISPERSION DE RAYOS-GAMMA

Se han implementado algunos procedimientos estándar de tratamiento digital de imágenes con el fin de aumentar la información obtenida de las imágenes generadas con un dispositivo de retrodispersión de rayos-gamma. Se implementaron tres métodos simples, restar una imagen de referencia, suavizado de la imagen y detección de bordes, y se observó una notable mejoría en la calidad de las imágenes.In order to extract more useful information from images obtained with a Gamma-ray Backscattering imaging device some methods of standard imaging treatment were implemented. Three very simple methods, subtract a reference image, smoothing and edge-detection, were implemented with a clear improvement on the image quality

Development of an Ion Thruster and Power Processor for New Millennium's Deep Space 1 Mission

The NASA Solar Electric Propulsion Technology Applications Readiness Program (NSTAR) will provide a single-string primary propulsion system to NASA's New Millennium Deep Space 1 Mission which will perform comet and asteroid flybys in the years 1999 and 2000. The propulsion system includes a 30-cm diameter ion thruster, a xenon feed system, a power processing unit, and a digital control and interface unit. A total of four engineering model ion thrusters, three breadboard power processors, and a controller have been built, integrated, and tested. An extensive set of development tests has been completed along with thruster design verification tests of 2000 h and 1000 h. An 8000 h Life Demonstration Test is ongoing and has successfully demonstrated more than 6000 h of operation. In situ measurements of accelerator grid wear are consistent with grid lifetimes well in excess of the 12,000 h qualification test requirement. Flight hardware is now being assembled in preparation for integration, functional, and acceptance tests

Assessment of Microplastics in the Surface Water of Sitio Pulo, Navotas, Metro Manila

Microplastics are synthetic polymer particles with a length of 5 mm or less with no well-defined lower boundary. These debris particles are known to affect marine and aquatic organisms which poses a threat to biodiversity and marine resources. In this study, the isolated microplastic from the coastal and lagoon surface waters of Sitio Pulo is described. Sitio Pulo is a barrier island mangrove sanctuary located at Brgy. Tanza I, Navotas City surrounded by Manila Bay. The samples collected last July 4 and 25, 2019, were isolated, profiled, and analyzed. A total of four hundred forty-nine (449) microplastic fragments were isolated from the surface water samples with a median length of 1.096 (IQR 0.809–1.578) mm. The isolated microplastics exhibit roundness, whiteness, and yellowing indicating signs of mechanical, chemical and photodegradation. It is also noted the putative effects of the weather disturbances in accelerating the discharge of nascent microplastics in Manila Bay. The isolated microplastic composition includes the commodity polymers polyethylene (PE) and polypropylene (PP). The presence of microplastics in the surface waters of Sitio Pulo reflects the worsening plastic pollution problem in Metro Manila

Temporal dynamics of the shrub and herbaceous layer of an area of moist grassland in Alto Paraíso de Goiás, Brazil

Este trabalho avaliou a dinâmica estrutural e fl orística de uma comunidade de espécies herbáceo-arbustivas de uma área de campo limpo úmido em Alto Paraíso de Goiás, o primeiro inventário realizado em 2000 (T0) e o segundo em 2007 (T1). A diversidade de Shannon entre os períodos foi comparada pelo teste-t de Hutcheson e a similaridade fl orística, pelo índice de similaridade de Chao-Sørensen. As relações fl orísticas e a cobertura, entre os períodos e as linhas, foram avaliadas por meio de análises de correspondência retifi cada (DCA). Foram amostradas 98 espécies, 88 no T0 e 67 no T1, sendo 31 exclusivas do T0 e 10 do T1. A diversidade fl orística na comunidade foi elevada nos dois períodos, porém diferente entre esses (t = 7,12; p < 0,001), devido a variação no número e cobertura das espécies. A similaridade entre os dois inventários foi alta (Chao-Sørensen ± IC = 0,841 ± 0,074). A ordenação por DCA indicou relações entre a composição fl orística e a cobertura com o gradiente de umidade e de matéria orgânica no solo identifi cados em T0. Houve modifi cações nas linhas em zonas sazonais, as quais se tornaram mais semelhantes às linhas constantemente saturadas por água. Em um intervalo de sete anos o campo limpo úmido apresentou mudanças na composição fl orística e, principalmente na estrutura devido o aumento da cobertura de espécies perenes, cespitosas e entouceiradas, que foram favorecidas pela maior umidade no solo em resposta à elevação da pluviosidade da região. __________________________________________________________________________________________ ABSTRACTTh is study evaluated the fl oristic and structural dynamics of a community of herbaceous-shrub species in an area of moist grassland in Alto Paraíso de Goiás. Th e fi rst inventory was undertaken in 2000 (T0) and the second in 2007 (T1). Shannon’s diversity between the periods was compared by Hutchesons´s t-test, and the fl oristic similarity by the Chao-Sørensen similarity index. Floristic composition and cover, between periods and lines, were evaluated by detrended correspondence analysis (DCA). We sampled 98 species, 88 at T0 and 67 at T1; 31 were unique to T0 and 10 to T1. Floristic diversity in the community was high in both periods, but diff erent between them (t = 7.12, p <0.001), due to variation in species number and coverage. Similarity between the two surveys was high (Chao-Sørensen CI = ± 0.841 ± 0.074). Th e DCA ordination indicated relationships between the fl oristic composition and cover with a gradient of moisture and organic matter in the soil identifi ed in T0. Th ere were changes in the lines in the seasonal zones, which became more similar in those constantly saturated with water. During an interval of seven years the moist grassland showed changes in fl oristic composition and mainly in structure due to increased cover of the clumped tussock perennial species, which were favored by higher soil moisture due to high rainfall in the region

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Photon-rejection Power of the Light Dark Matter eXperiment in an 8 GeV Beam

The Light Dark Matter eXperiment (LDMX) is an electron-beam fixed-target experiment designed to achieve comprehensive model independent sensitivity to dark matter particles in the sub-GeV mass region. An upgrade to the LCLS-II accelerator will increase the beam energy available to LDMX from 4 to 8 GeV. Using detailed GEANT4-based simulations, we investigate the effect of the increased beam energy on the capabilities to separate signal and background, and demonstrate that the veto methodology developed for 4 GeV successfully rejects photon-induced backgrounds for at least $2\times10^{14}$ electrons on target at 8 GeV.Comment: 28 pages, 20 figures; corrected author lis