109 research outputs found

    Unifying (Machine) Vision via Counterfactual World Modeling

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    Leading approaches in machine vision employ different architectures for different tasks, trained on costly task-specific labeled datasets. This complexity has held back progress in areas, such as robotics, where robust task-general perception remains a bottleneck. In contrast, "foundation models" of natural language have shown how large pre-trained neural networks can provide zero-shot solutions to a broad spectrum of apparently distinct tasks. Here we introduce Counterfactual World Modeling (CWM), a framework for constructing a visual foundation model: a unified, unsupervised network that can be prompted to perform a wide variety of visual computations. CWM has two key components, which resolve the core issues that have hindered application of the foundation model concept to vision. The first is structured masking, a generalization of masked prediction methods that encourages a prediction model to capture the low-dimensional structure in visual data. The model thereby factors the key physical components of a scene and exposes an interface to them via small sets of visual tokens. This in turn enables CWM's second main idea -- counterfactual prompting -- the observation that many apparently distinct visual representations can be computed, in a zero-shot manner, by comparing the prediction model's output on real inputs versus slightly modified ("counterfactual") inputs. We show that CWM generates high-quality readouts on real-world images and videos for a diversity of tasks, including estimation of keypoints, optical flow, occlusions, object segments, and relative depth. Taken together, our results show that CWM is a promising path to unifying the manifold strands of machine vision in a conceptually simple foundation

    Antifungal activity of extracts, essential oil and constituents from Petroselinum crispum against Colletotrichum acutatum

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    The effect of extracts, essential oil, and their major constituents from parsley (Petroselinum crispum (Mill.) Fuss.) against the phytopathogenic fungus Collectotrichum acutatum was evaluated by the poisoned agar method. Results showed that all extracts, along with the essential oil, significantly inhibit the radial growth of C. acutatum at concentrations higher than 100 μg mL-1. The higher activity was found for the essential oil followed by the n-hexane extract. Analysis by gas chromatography with mass spectroscopy (GC-MS) of n-hexane extract and the essential oil of P. crispum showed that the major components correspond to the phenylpropanoids myristicin and parsley-apiole. Both compounds were isolated by conventional chromatographic techniques and their structures elucidated by spectroscopicmethods. Myristicin and parsley-apiole displayed a significant inhibitory effect against C. acutatum. The highest fungistatic activity was found to parsley-apiole with IC50 value of 40 μg mL-1. In conclusion, parsley may be a good source of antifungal compounds to control C. acutatum.Se evaluó el efecto de extractos, el aceite esencial y los componentes principales del perejil (Petroselinum crispum (Mill.) Fuss.) contra el hongo fitopatógeno Collectotrichum acutatum mediante el método del agar envenenado. Los resultados mostraron que todos los extractos, junto con elaceite esencial, inhibieron significativamente el crecimiento radial de C. acutatum en concentraciones superiores a 100 μg mL-1. La mayor actividad se encontró para el aceite esencial, seguido por el extracto de n-hexano. El análisis por cromatografía de gases con espectroscopia de masas (CG-EM)del extracto de n-hexano y el aceite esencial de P. crispum mostró que los componentes principales corresponden a los fenilpropanoides miristicina y parsley-apiol. Ambos compuestos fueron aislaron por técnicas cromatográficas convencionales y sus estructuras elucidadas por métodos espectroscópicos. La miristicina y el parsley-apiol mostraron un efecto inhibidor significativo contra C. acutatum. La actividad fungistática más alta se encontró para parsley-apiol con un valor CI50 de 40 μg mL-1. Enconclusión, el perejil puede ser una buena fuente de compuestos antimicóticos para controlar el C. acutatum

    Exposición a mercurio en habitantes del municipio de san marcos (departamento de sucre) debida a la ingesta de arroz (oryza sativa) contaminado

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    Objetivo Determinar la magnitud de la exposición a mercurio en los habitantes del municipio de San Marcos debida a la ingesta de arroz (Oryza sativa) contaminado.Métodos Se seleccionaron 20 personas representativas de la población y se tomaron muestras del alimento (arroz crudo) y muestras de cabello para determinar mercurio total y metilmercurio mediante la técnica de espectrofotometría de absorción atómica por vapor frio. Para realizar comparaciones entre las distintas muestras se realizaron t-test, tomando un grado de significancia P and lt;0.05 y para determinar la relación entre los hábitos de consumo y la concentración de mercurio en humanos se realizó un análisis de correlación.Resultados El arroz comercializado de forma suelta (arroz blanco de San Marcos) fue el único que mostró una mínima concentración de mercurio total de 0,021 μg/g, mientras que los que se comercializan de forma empacada no arrojaron un valor cuantificable. Solo el 5 % de la muestra poblacional excedió la dosis de referencia e Ingestión de MeHg (RfD) establecida por la EPA,de 0,1 μg/Kg de peso corporal/día.Conclusiones La exposición a HgT de los habitantes del municipio de San Marcos por consumo de arroz es baja y no implica grandes riesgos para su salud. No obstante, el consumo frecuente de otros alimentos contaminados podría representar una amenaza potencial para la salud de los consumidores, lo cual hace necesario su permanente monitoreo ambiental

    Prototipo de incubadora neonatal

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    Las incubadoras neonatales proporcionan un entorno controlado para recién nacidos que necesitan cuidados especiales. Este prototipo ha sido diseñado para cubrir las necesidades mínimas en los hospitales, de modo que el personal médico pueda controlar el entorno del neonato. Este artículo reporta el diseño y construcción de un prototipo que incluyó una investigación con el fin de seleccionar y construir los elementos del prototipo: chasis, cúpula, portacolchón y una fuente de poder. Dentro de la incubadora se dispusieron sensores de temperatura, luminosidad, ruido, humedad y una alarma de apertura de la puerta; todos con el fin de garantizar el buen estado de salud del neonato. Con estos elementos, se pudo obtener un prototipo funcional, que se convierte en un primer paso para el desarrollo de incubadoras neonatales con tecnología apropiada.Newborn and premature infants incubators provide a controlled environment for infants which need special care. The constructed prototype has the potential to cover the minimal needs in a hospital, in a way that medical staff may control the newborn environment. This article reports the design and construction of the prototype included research for selecting and building the elements of the prototype: the chassis, hood, mattress case, and a power source. Different transducers were included in the incubator for measuring temperature, luminosity, noise, humidity, and a door alarm. The purpose of these was to guaranty the proper conditions for the newborn.The constructed prototype is fully functional and constitutes a first step for building newborn incubators with appropriated technology

    VOLUMEN 15, NÚMERO 29 (1981-1982)

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    USO DEL COMPUTADOR EN EL ANÁLISIS SEDIMENTOLÓGICO Y DE MIGRACIÓN DE FLUIDOS Y SU APLICACIÓN EN EL NOROCCIDENTE COLOMBIANO. Castro, A. E.; Molina, G. J.UN MODELO ESTRUCTURAL PARA EL VALLE DEL CAUCA Y SUS IMPLICACIONES HIDROGEOLÓGICAS Y MINERAS. Padilla, L. E.TECTÓNICA DE SOBRECORRIMIENTO Y SUS IMPLICACIONES ESTRUCTURALES EN EL ÁREA PAMPLONA - CORDILLERA ORIENTAL DE COLOMBIA. Boinet, T.; Bourgois, J.; Mendoza F. HGEOLOGÍA DE LAS LATERITAS NIQUELÍFERAS DE CERRO MATOSO S. A. Mejía, V. M.; Durango, J. R.COMPLEJO OFIOLÍTICO EN LA CUENCA DEL RÍO GUAPI. Ortega Montero, C.DETERMINACIÓN DE RESERVAS DE DEPÓSITOS MINERALES. Hernández Garay, H.CARACTERIZACIÓN, RANGO Y CLASIFICACIÓN DE CARBONES. Ramírez Castro, P

    Identifying patterns of alumni commitment in key strategic relationship programmes

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    Higher education institutions (HEIs) need to understand their alumni when drawing strategic relationship programmes. This paper aims to identify clusters of alumni based on their commitment relationship and to analyse factors influencing their intention to collaborate with the HEI. The study took place at a Portuguese university, considering a dataset of 1075 of alumni asserting intention to collaborate. First, a cluster analysis was conducted to identify patterns of commitment relationship. Secondly, a logistic regression was run to identify determinants of intention to collaborate. Both techniques revealed the decisive role of HEI commitment in the process. Relationship advantages and positive feelings towards the HEI were also pointed out as important. Alumni asserted recommendations, further training, sharing experiences and giving help as ways to collaborate with HEI. Regression results suggest that sociodemographic variables such as gender, marital status and volunteering are significantly associated with a probability to collaborate. Results also show that affiliation in sororities/fraternities and participation in extracurricular activities are significantly associated with that collaborative intention. The findings provide clues to support strategic relationship programmes based on consistent marketing campaigns, while bringing value to the literature in the European context, where alumni culture requires real insights to evolve.info:eu-repo/semantics/publishedVersio
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