346 research outputs found
Passive Millimeter Wave Imaging Camera ViKy as Technology Transfer of Planck-LFI
The passive Video camera for Imaging in Ka-band, named ViKy project, was born in 2004 as one of the possible spin-off based on the technology transfer of ESA PLANCK satellite thanks to an idea of Professor Nazzareno Mandolesi and Ing. Enrico Pagana. In 2004 the I ASF team - compound also by Ing. Adriano De Rosa, Dr. Carlo Burigana, Ing. Valerio Martorelli, Dr. Luca Stringhetti, Dr. Luca Valenziano, Dr. Fabrizio Villa and myself - ventured to raise the ViKy project.
The aim of the ViKy system is to provide a real time optical image, obtained from the radiometric signal by imaging processing, for commercial applications. ViKy is a passive system because it does not need to illuminate the target (or an object in a scene) with an external radiation source as it happens for example in a radar system. The detected signal is given by the sum of the emitted and reflected component by the target object.
The PPMMW imaging is a method of forming images through the passive detection of millimeter-wave radiation from a scene. In this way it is possible to form images during the day or night; in clear weather or in low-visibility conditions, such as haze, fog, clouds, smoke, or sandstorms; and even through clothing. This ability permits to see under conditions of low visibility otherwise visible or infrared (IR) sensors can do.
In the commercial field such a system could be adopted by the airport companies to improve the capability of the security systems usually used to aid the aircrafts during the take-off or the landing phases. For security concerns, imaging of concealed weapons could be accomplished in a non intrusive manner with PMMW imaging.
At system level the prototype can be separate in five units: the antenna ystem able to scan the scene quickly; the antenna electronics control that allows to carry out the scansion of the image; the radiometer that amplifies and detect the electromagnetic signal coming from the antenna; the Data Acquisition Electronics; the software for the image processing and the final interface.
A key part of ViKy project is the design of a compact and low cost antenna working at 35 GHz and based on the reflectarray concept. Although this concept has been performed during the last years, only few 35 GHz reflectarrays exist. The reflectarray antenna consists of a flat reflecting surface and an illuminating feed horn placed in an off set or on set geometrical configuration depending on the requirements. On the reflecting surface, there are many isolated elements, named patches, which are designed to scatter the incident field and to form a planar wave front in the far-field. The second ViKy subsystem is the total power radiometer that was born from the millimeter waves technologies involved in the Low Frequency Instrument of PLANCK satellite. The radiometer amplifies and detects the signals coming from the antenna. The prototype that has been realized is based on a mechanical beam scanning necessary to reconstruct the image. In future will be possible to improve the ViKy system replacing the mechanical beam forming with an electronic beam forming using a particular kind of diode's technology. The data acquisition electronic and the software for the image reconstruction are the final subsystems of the imaging camera.
All the ViKy components have been designed, assembled and finally tested by myself with the supervision of the IASF team. Mine PhD thesis summarizes the ViKy project starting from its principal and crucial aspects and finally presenting the results achieved. The measurements demonstrates the accordance with the required specifications.
A pre-patent investigation highlighted the originality and newness of our project since to date no other passive system, coupled with a reflectarray antenna, has never been proposed. This demonstrates the full potential of the ViKy system in term of feasibility and commercial applications
Recombinant DNA Molecules of Bacteriophage phi X174
phi X174 DNA structures containing two different parental genomes were detected genetically and examined by electron microscopy. These structures consisted of two monomeric double-stranded DNA molecules linked in a figure 8 configuration. Such DNA structures were observed to be formed preferentially in host recA+ cells or recA+ cell-free systems. Since the host recA+ allele is required for most phi X174 recombinant formation, we conclude that the observed figure 8 molecules are intermediates in, or end products of, a phi X174 recombination event. We propose that recombinant figure 8 DNA molecules arise as a result of "single-strand aggression," are stabilized by double-strand "branch migration," and represent a specific example of a common intermediate in genetic recombination
Deletion mutants of bacteriophage phiX174
Mutants of bacteriophage phiX174 have been isolated that are less dense than wild-type phiX particles in CsCl. When mutant viral (+) strand DNA and wild-type complementary (-) strand DNA are hybridized, the resulting duplex molecules have single-stranded loops characteristic of wild-type-deletion heteroduplexes. The mutant bacteriophages fail to complement phiX amber mutants in cistron E. We conclude that the mutant viruses have deleted approximately 7% of the phiX genome in the region of cistron E
Improving the Practice Model in a Military Clinic
Military members and their families face numerous stressors due to the unique lifestyle of this career (Lester, 2011). The occupational impact on these members creates a highly stressful and physically demanding environment with low morale, chronic medical complaints, and poor mental health for these individuals. This project incorporated the current patient-centered medical home (PCMH) model and fused it with the operational medical model for all the active duty members in this unit. The combination of models allowed the provider to have a better understanding of the population’s needs. By embedding in the units, the provider developed a team approach to disease prevention, health awareness, injury reduction, and allowed for better access to care. The team and leadership worked together and determined the needs of the population and developed a plan to meet those needs
Genetic Recombination in Bacteriophage {varphi}X174
Genetic recombination in bacteriophage {varphi}X174 usually takes place early in the infection process and involves two parental replicative form (double-stranded) DNA molecules. The host recA protein is required; none of the nine known {varphi}X174 cistron products is essential. The products of a single recombination event are nonreciprocal and asymmetric. Typically, only one of the parental genotypes and one recombinant genotype are recovered from a single cell. An alternative, less efficient recombination mechanism which requires an active {varphi}X174 cistron A protein is observed in the absence of the host recA gene product
Arqueología y fuentes históricas: Diálogos interdisciplinarios
El presente trabajo tiene como objetivo exponer la problemática del uso de fuentes históricas en la investigación arqueológica. Estas fuentes pueden aplicarse tanto como líneas de evidencia independientes sobre el pasado, como para generar hipótesis sobre un registro arqueológico dado. Se presentarán entonces dos casos de estudio que aplican el estudio de las fuentes históricas en arqueología, desde distintas problemáticas y también disímiles geografías y cronologías. Desde la arqueología urbana de Buenos Aires, se investigan el desarrollo de la industria local del vidrio y las prácticas de consumo asociadas, analizando las coincidencias y discordancias entre los datos históricos y el registro arqueológico (s. XIX-XX). El segundo caso aborda, desde la arqueología del paisaje, el estudio de las vías de tránsito y comunicación en el sector oriental de Catamarca, en articulación con la aplicación del Sistema de Información Geográfica (SIG). Ambos ejemplos enfatizarán la importancia de aplicar una metodología interdisciplinaria que incorpore a la historia, a fin de lograr una visión multidimensional de cada fenómeno social en cuestión.The aim of this article is to consider the issues regarding the use of historical sources in the archaeological research. These sources can be applied both as independent evidence about the past, or in order to produce hypotheses about the archaeological data. In this way, we present two cases of study that apply the use of historical sources in archaeology, parting from different research problems and different chronologies and locations. In the case of the urban archaeology of Buenos Aires, the development of the local glass industry and the consumption practices related to it is investigated by analyzing both similarities and discrepancies between the historical data and the archaeological registry (XIX-XX centuries). The second case is about the study of the ways of communication and movement through eastern Catamarca province (Argentina) both from Landascape Archaeology and the use of Geographic Information Systems (GIS). Both examples will focus on the importance of the application of a interdisciplinary methodology that includes History, as a mean to achieve a multidimensional view of every social phenomena in discussion.Fil: Traba, Aniela Romina. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Instituto de Arte Americano e Investigaciones Estéticas ; ArgentinaFil: Verónica Zuccarelli. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; Argentin
Mecanismo cinético de la oxidación del propileno a acroleína y anhídrido carbónico, sobre óxido de cobre como catalizador
Se ha estudiado la cinética de la oxidación catalítica del r propileno a acroleína y anhídrido carbónico, a 350°C, usando como catalizador óxido de cobre al 1,55% sobre carburo de silicio como soporte. Se usó un micro reactor diferencial y se variaron independientemente las presiones parciales de: Propileno: de 0,08 a 0,895 atm. Oxígeno: de 0,05 a 0,21 atm. Anhídrido carbónico: de 0,0 a 0,10 atm. Agua: de 0,0 a 0,12 atm. Aeroleína: de 0,0 a 0,03 atm.usando nitrógeno para completar la dierencia. Se ha comprobado que las velocidades de formación de acroleína y anhídrido carbónico dependen de la concentración de oxígeno, muy poco de la concentración de propileno y de anhídrido carbónico y son inhibidas por el agua y la acroleína. La curva de velocidades de reacción en función de la concentración del propileno parecería indicar un cambio en la composición del catalizador, y se encontró que por encima de cierta relación oxígeno: propileno se inactiva el catalizador para la formación de acroleína y aumenta la actividad para la de anhídrido carbónico. Siguiendo el método de cuadrados mínimos preconizado por Hougen y Watson se encontró que el mecanismo cinético de esta reacción ocurre entre oxígeno atómicamente adsorbido y propileno en la fase gaseosa, siendo la etapa controladora la adsorción del oxígeno. Las ecuaciones cinéticas que mejor describen el fenómeno son: Para la oxidación a acroleína:r1=37,21 pO2/(2(1+54,03 pAcrol.+4,04 pH2O)^2)y para la oxidación total:r2=4,43pO2/(2(1+12,42 pAcrol.+22,05 pH2O)^2)Fil: Zuccarelli, Ricardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
La web semántica como plataforma para sistemas de recomendación
En la actualidad los Sistemas de Recomendación se han convertido en una de las herramientas más importantes en los sitios web que ofrecen diversos tipos de contenido a sus usuarios. La implementación de estos en determinados contextos puede requerir de una fuente de datos que proporcione la información necesaria para que puedan cumplir su objetivo exitosamente. La Web Semántica ofrece determinadas características que parecen posicionarla como un gran candidato como plataforma para abastecer de la información necesaria mencionada anteriormente. En esta tesis se evaluará la viabilidad de sacar provecho a la Web Semántica para la construcción de un Sistema de Recomendación bajo el contexto de Reviews de ítems mediante establecer y documentar una estrategia que involucra pasos de obtención, extracción, evaluación, curado, integración, publicación y explotación, la cual fue utilizada para construir una aplicación de ejemplo. Se detallarán cada uno de estos pasos incluyendo las herramientas utilizadas para llevarlos a cabo (además de la mención de otras herramientas posibles), así como también los resultados obtenidos luego de la conclusión de cada uno de estos. Por último se presentarán las conclusiones, trabajo a futuro y artículos derivados de realizar la tesis.Facultad de Informátic
- …