Model Diagnostics in the presence of measurement error

The problem of using information available from one variable X to make inferenceabout another Y is classical in many physical and social sciences. In statistics this isoften done via regression analysis where mean response is used to model the data. Onestipulates the model Y = µ(X) +ɛ. Here µ(X) is the mean response at the predictor variable value X = x, and ɛ = Y - µ(X) is the error. In classical regression analysis, both (X; Y ) are observable and one then proceeds to make inference about the mean response function µ(X). In practice there are numerous examples where X is not available, but a variable Z is observed which provides an estimate of X. As an example, consider the herbicidestudy of Rudemo, et al. [3] in which a nominal measured amount Z of herbicide was applied to a plant but the actual amount absorbed by the plant X is unobservable. As another example, from Wang [5], an epidemiologist studies the severity of a lung disease, Y , among the residents in a city in relation to the amount of certain air pollutants. The amount of the air pollutants Z can be measured at certain observation stations in the city, but the actual exposure of the residents to the pollutants, X, is unobservable and may vary randomly from the Z-values. In both cases X = Z+error: This is the so called Berkson measurement error model.In more classical measurement error model one observes an unbiased estimator W of X and stipulates the relation W = X + error: An example of this model occurs when assessing effect of nutrition X on a disease. Measuring nutrition intake precisely within 24 hours is almost impossible. There are many similar examples in agricultural or medical studies, see e.g., Carroll, Ruppert and Stefanski [1] and Fuller [2], , among others. In this talk we shall address the question of fitting a parametric model to the re-gression function µ(X) in the Berkson measurement error model: Y = µ(X) + ɛ; X = Z + η; where η and ɛ are random errors with E(ɛ) = 0, X and η are d-dimensional, and Z is the observable d-dimensional r.v.

Hydrogeology and hydrochemistry of the aquifer systems of Kuttanad area, Kerala: Their role in understanding the evolution of groundwaters

This is an attempt to understand the important factors that control the occurrence, development and hydrochemical evolution of groundwater resources in sedimentary multi aquifer systems. The primary objective of this work is an integrated study of the hydrogeology and hydrochemistry with a view to elucidate the hydrochemical evolution of groundwater resources in the aquifer systems. The study is taken up in a typical coastal sedimentary aquifer system evolved under fluvio-marine environment in the coastal area of Kerala, known as the Kuttanad. The present study has been carried out to understand the aquifer systems, their inter relationships and evolution in the Kuttanad area of Kerala. The multi aquifer systems in the Kuttanad basin were formed from the sediments deposited under fluvio-marine and fluvial depositional environments and the marine transgressions and regressions in the geological past and palaeo climatic conditions influenced the hydrochemical environment in these aquifers. The evolution of groundwater and the hydrochemical processes involved in the formation of the present day water quality are elucidated from hydrochemical studies and the information derived from the aquifer geometry and hydraulic properties. Kuttanad area comprises of three types of aquifer systems namely phreatic aquifer underlain by Recent confined aquifer followed by Tertiary confined aquifers. These systems were formed by the deposition of sediments under fluvio-marine and fluvial environment. The study of the hydrochemical and hydraulic properties of the three aquifer systems proved that these three systems are separate entities. The phreatic aquifers in the area have low hydraulic gradients and high rejected recharge. The Recent confined aquifer has very poor hydraulic characteristics and recharge to this aquifer is very low. The Tertiary aquifer system is the most potential fresh water aquifer system in the area and the groundwater flow in the aquifer is converging towards the central part of the study area (Alleppey town) due to large scale pumping of water for water supply from this aquifer system. Mixing of waters and anthropogenic interferences are the dominant processes modifying the hydrochemistry in phreatic aquifers. Whereas, leaching of salts and cation exchange are the dominant processes modifying the hydrochemistry of groundwater in the confined aquifer system of Recent alluvium. Two significant chemical reactions modifying the hydrochemistry in the Recent aquifers are oxidation of iron in ferruginous clays which contributes hydrogen ions and the decomposition of organic matter in the aquifer system which consumes hydrogen ions. The hydrochemical environment is entirely different in the Tertiary aquifers as the groundwater in this aquifer system are palaeo waters evolved during various marine transgressions and regressions and these waters are being modified by processes of leaching of salts, cation exchange and chemical reactions under strong reducing environment. It is proved that the salinity observed in the groundwaters of Tertiary aquifers are not due to seawater mixing or intrusion, but due to dissolution of salts from the clay formations and ion exchange processes. Fluoride contamination in this aquifer system lacks a regional pattern and is more or less site specific in natureThe lowering of piezometric heads in the Tertiary aquifer system has developed as consequence of large scale pumping over a long period. Hence, puping from this aquifer system is to be regulated as a groundwater management strategy. Pumping from the Tertiary aquifers with high capacity pumps leads to well failures and mixing of saline water from the brackish zones. Such mixing zones are noticed from the hydrochemical studies. This is the major aquifer contamination in the Tertiary aquifer system which requires immediate attention. Usage of pumps above 10 HP capacities in wells taping Tertiary aquifers should be discouraged for sustainable development of these aquifers. The recharge areas need to be identified precisely for recharging the aquifer systems throughartificial means.

Novel Electrochemical and Fluorescence Sensors for Food Additives and Neurotransmitters

There is an enormous demand for chemical sensors in many areas and disciplines including chemistry, biology, clinical analysis, environmental science. Chemical sensing refers to the continuous monitoring of the presence of chemical species and is a rapidly developing field of science and technology. They are analytical devices which transform chemical information generating from a reaction of the analyte into an measurable signal. Due to their high selectivity, sensitivity, fast response and low cost, electrochemical and fluorescent sensors have attracted great interest among the researchers in various fields. Development of four electrochemical sensors and three fluorescent sensors for food additives and neurotransmitters are presented in the thesis. Based on the excellent properties of multi walled carbon nanotube (MWCNT), poly (L-cysteine) and gold nanoparticles (AuNP) four voltammetric sensors were developed for various food additives like propyl gallate, allura red and sunset yellow. Nanosized fluorescent probes including gold nanoclusters (AuNCs) and CdS quantum dots (QDs) were used for the fluorescent sensing of butylated hydroxyanisole, dopamine and norepinephrine. A total of seven sensors including four electrochemical sensors and three fluorescence sensors have been developed for food additives and neurotransmitters.

Development of Electrochemical and Fluorescent Sensors

Chemical sensors have growing interest in the determination of food additives, which are creating toxicity and may cause serious health concern, drugs and metal ions. A chemical sensor can be defined as a device that transforms chemical information, ranging from the concentration of a specific sample component to total composition analysis, into an analytically useful signal. The chemical information may be generated from a chemical reaction of the analyte or from a physical property of the system investigated. Two main steps involved in the functioning of a chemical sensor are recognition and transduction. Chemical sensors employ specific transduction techniques to yield analyte information. The most widely used techniques employed in chemical sensors are optical absorption, luminescence, redox potential etc. According to the operating principle of the transducer, chemical sensors may be classified as electrochemical sensors, optical sensors, mass sensitive sensors, heat sensitive sensors etc. Electrochemical sensors are devices that transform the effect of the electrochemical interaction between analyte and electrode into a useful signal. They are very widespread as they use simple instrumentation, very good sensitivity with wide linear concentration ranges, rapid analysis time and simultaneous determination of several analytes. These include voltammetric, potentiometric and amperometric sensors. Fluorescence sensing of chemical and biochemical analytes is an active area of research. Any phenomenon that results in a change of fluorescence intensity, anisotropy or lifetime can be used for sensing. The fluorophores are mixed with the analyte solution and excited at its corresponding wavelength. The change in fluorescence intensity (enhancement or quenching) is directly related to the concentration of the analyte. Fluorescence quenching refers to any process that decreases the fluorescence intensity of a sample. A variety of molecular rearrangements, energy transfer, ground-state complex formation and collisional quenching. Generally, fluorescence quenching can occur by two different mechanisms, dynamic quenching and static quenching. The thesis presents the development of voltammetric and fluorescent sensors for the analysis of pharmaceuticals, food additives metal ions. The developed sensors were successfully applied for the determination of analytes in real samples. Chemical sensors have multidisciplinary applications. The development and application of voltammetric and optical sensors continue to be an exciting and expanding area of research in analytical chemistry. The synthesis of biocompatible fluorophores and their use in clinical analysis, and the development of disposable sensors for clinical analysis is still a challenging task. The ability to make sensitive and selective measurements and the requirement of less expensive equipment make electrochemical and fluorescence based sensors attractive.

Efficient Characterisation and Optimal Control of Open Quantum Systems - Mathematical Foundations and Physical Applications

Since no physical system can ever be completely isolated from its environment, the study of open quantum systems is pivotal to reliably and accurately control complex quantum systems. In practice, reliability of the control field needs to be confirmed via certification of the target evolution while accuracy requires the derivation of high-fidelity control schemes in the presence of decoherence. In the first part of this thesis an algebraic framework is presented that allows to determine the minimal requirements on the unique characterisation of arbitrary unitary gates in open quantum systems, independent on the particular physical implementation of the employed quantum device. To this end, a set of theorems is devised that can be used to assess whether a given set of input states on a quantum channel is sufficient to judge whether a desired unitary gate is realised. This allows to determine the minimal input for such a task, which proves to be, quite remarkably, independent of system size. These results allow to elucidate the fundamental limits regarding certification and tomography of open quantum systems. The combination of these insights with state-of-the-art Monte Carlo process certification techniques permits a significant improvement of the scaling when certifying arbitrary unitary gates. This improvement is not only restricted to quantum information devices where the basic information carrier is the qubit but it also extends to systems where the fundamental informational entities can be of arbitary dimensionality, the so-called qudits. The second part of this thesis concerns the impact of these findings from the point of view of Optimal Control Theory (OCT). OCT for quantum systems utilises concepts from engineering such as feedback and optimisation to engineer constructive and destructive interferences in order to steer a physical process in a desired direction. It turns out that the aforementioned mathematical findings allow to deduce novel optimisation functionals that significantly reduce not only the required memory for numerical control algorithms but also the total CPU time required to obtain a certain fidelity for the optimised process. The thesis concludes by discussing two problems of fundamental interest in quantum information processing from the point of view of optimal control - the preparation of pure states and the implementation of unitary gates in open quantum systems. For both cases specific physical examples are considered: for the former the vibrational cooling of molecules via optical pumping and for the latter a superconducting phase qudit implementation. In particular, it is illustrated how features of the environment can be exploited to reach the desired targets.

Visual Speech Synthesis by Morphing Visemes

We present MikeTalk, a text-to-audiovisual speech synthesizer which converts input text into an audiovisual speech stream. MikeTalk is built using visemes, which are a small set of images spanning a large range of mouth shapes. The visemes are acquired from a recorded visual corpus of a human subject which is specifically designed to elicit one instantiation of each viseme. Using optical flow methods, correspondence from every viseme to every other viseme is computed automatically. By morphing along this correspondence, a smooth transition between viseme images may be generated. A complete visual utterance is constructed by concatenating viseme transitions. Finally, phoneme and timing information extracted from a text-to-speech synthesizer is exploited to determine which viseme transitions to use, and the rate at which the morphing process should occur. In this manner, we are able to synchronize the visual speech stream with the audio speech stream, and hence give the impression of a photorealistic talking face.

Automatic classification of breast density

A recent trend in digital mammography is computer-aided diagnosis systems, which are computerised tools designed to assist radiologists. Most of these systems are used for the automatic detection of abnormalities. However, recent studies have shown that their sensitivity is significantly decreased as the density of the breast increases. This dependence is method specific. In this paper we propose a new approach to the classification of mammographic images according to their breast parenchymal density. Our classification uses information extracted from segmentation results and is based on the underlying breast tissue texture. Classification performance was based on a large set of digitised mammograms. Evaluation involves different classifiers and uses a leave-one-out methodology. Results demonstrate the feasibility of estimating breast density using image processing and analysis techniques

Caracterización del ausentismo laboral en un centro medico de I nivel

El ausentismo laboral es un fenómeno costoso. Cuando los trabajadores no asisten por enfermedad o accidentes laborales, el impacto que sufre la empresa es en el ámbito económico y/u operativo. Objetivo: Caracterizar los factores del ausentismo laboral en un centro médico de I nivel y su comportamiento durante el año 2010. Métodos: Estudio descriptivo de corte transversal, 118 trabajadores del centro médico de I nivel en Bogotá durante el año 2010.Criterios de inclusión: hombres y mujeres, con contratación directa, incapacidades médicas. Criterios de exclusión: personal de contratación indirecta, outsourcing, calamidades y licencias de maternidad. Información tomada base de datos incapacidades. Resultados: Se presentaron 332 incapacidades que representaron 1518 días perdidos causados por enfermedad general 99.7 %, sistemas respiratorio, digestivo y osteomuscular con mayor número de incapacidades (31,9%, 22,9% y 13% respectivamente). El mayor ausentismo en médicos fue 38,3%, auxiliares odontología 14,2 % y odontólogos 10,8%. El área asistencial tiene 78,3% incapacidades, contratos a término indefinido con un 74.6% y mujeres con 78,01% incapacidades. Conclusiones: La mayor causa del ausentismo es enfermedad general. El sistema respiratorio es el más afectado, seguido del digestivo y osteomuscular, los trabajadores con contrato indefinido, género femenino, área asistencial y por cargos los médicos seguido de auxiliares odontología y los odontólogos. Sin embargo en los resultados evidenciados se debe tener en cuenta la población general y su distribución para variables como género, área, cargos, por lo que se requiere posteriormente análisis estadísticos para establecer si hay diferencia significativa.

Descripción de la estructura organizacional del área de Responsabilidad Social del Helm Bank en el año 2012

La investigación que se presenta a continuación reconstruye las acciones de la Responsabilidad Social Empresarial en el sector financiero Colombiano, congregando información académica donde los autores; teóricos y ejecutores, analizan y ofrecen pautas para el actuar responsable y sostenible en una organización. Así mismo este trabajo pone a la vista del lector información recopilada fruto de fuentes primarias, producto de conversaciones con la directiva en el área de Sostenibilidad del Helm Bank, integrante del sector financiero Colombiano y al gremio de bancos más relevantes en el país ASOBANCARIA. El direccionamiento de esta investigación se centra en la identificación del diseño estructural de un área de RSE en el sector financiero y sus componentes definidos en las siguientes variables; Evolución del área, Coordinación del trabajo, División laboral y Plataforma Estratégica Como resultado de dicha investigación se encontraron interesantes elementos. Dentro de estos elementos se hace especial mención a la sinergia que unen la planeación estratégica empresarial con las prácticas de Sostenibilidad, la directa conexión de la alta gerencia con el área de Responsabilidad Empresarial y con especial agrado la enorme puesta en marcha de acciones responsables en las tres dimensiones; social, ambiental y económica por parte de algunas entidades de la banca nacional en torno a sus actores de interés.

Hierarchical Prediction Machines and Big Data Analytics

An emerging consensus in cognitive science views the biological brain as a hierarchically-organized predictive processing system. This is a system in which higher-order regions are continuously attempting to predict the activity of lower-order regions at a variety of (increasingly abstract) spatial and temporal scales. The brain is thus revealed as a hierarchical prediction machine that is constantly engaged in the effort to predict the flow of information originating from the sensory surfaces. Such a view seems to afford a great deal of explanatory leverage when it comes to a broad swathe of seemingly disparate psychological phenomena (e.g., learning, memory, perception, action, emotion, planning, reason, imagination, and conscious experience). In the most positive case, the predictive processing story seems to provide our first glimpse at what a unified (computationally-tractable and neurobiological plausible) account of human psychology might look like. This obviously marks out one reason why such models should be the focus of current empirical and theoretical attention. Another reason, however, is rooted in the potential of such models to advance the current state-of-the-art in machine intelligence and machine learning. Interestingly, the vision of the brain as a hierarchical prediction machine is one that establishes contact with work that goes under the heading of 'deep learning'. Deep learning systems thus often attempt to make use of predictive processing schemes and (increasingly abstract) generative models as a means of supporting the analysis of large data sets. But are such computational systems sufficient (by themselves) to provide a route to general human-level analytic capabilities? I will argue that they are not and that closer attention to a broader range of forces and factors (many of which are not confined to the neural realm) may be required to understand what it is that gives human cognition its distinctive (and largely unique) flavour. The vision that emerges is one of 'homomimetic deep learning systems', systems that situate a hierarchically-organized predictive processing core within a larger nexus of developmental, behavioural, symbolic, technological and social influences. Relative to that vision, I suggest that we should see the Web as a form of 'cognitive ecology', one that is as much involved with the transformation of machine intelligence as it is with the progressive reshaping of our own cognitive capabilities.

Importación de panela en polvo y en sobres de sabores de Colombia hacia Argentina estudio realizado desde Buenos Aires - Argentina

Con el nacimiento de la globalización y su idea de integración de naciones para crear un solo mercado, se crea la necesidad en las empresas de expandir sus productos hacia nuevas fronteras para crear así empresas multiculturales que se adapten a los cambios constantes del entorno. Es allí donde nace el concepto de Unidad Estratégica de Negocio (UEN), la cual se puede definir como una subdivisión de una empresa, es una unidad de la empresa que tiene misión y objetivos aparte que se pueden planear con independencia de los demás negocios de la empresa1 . La panela es un producto Colombiano que nace de la extracción del jugo de la caña de azúcar, se consume fría o caliente de acuerdo a la preferencia del consumidor; hoy en día Doña panela, una de las empresas productoras de panela más grande del país, ha sacado al mercado una presentación de panela instantánea en cubos y sobres de diferentes sabores. Doña panela es una empresa que cuenta con todos los estándares legales establecidos para exportar y desde hace algunos años exporta hacia países como Corea del sur, ecuador y Estados Unidos; Siendo así, y gracias a la experiencia vivida en Argentina, se establece la idea de crear una Unidad Estratégica de Negocio de Doña panela en el bello país de Argentina.

Desarrollo kinesiológico: la interpretación de un proceso para facilitar el movimiento corporal humano

Este artículo hace una revisión del proceso de producción del movimiento funcional durante el primer año de vida, en un marco kinesiológico, donde se toma el tronco como estabilizador y eje principal en la ejecución motora de las extremidades. La interpretación presentada, facilita el entendimiento de los elementos motores básicos necesarios para construir una actividad más compleja y funcional, lo cual fortalece la habilidad del profesional para observar, evaluar y enfocar su acción en el manejo de personas con discapacidad funcional motora. Esta información es producto de la revisión de la literatura relacionada con el desarrollo normal del movimiento corporal humano y la observación directa del proceso de desarrollo normal y anormal en múltiples niños durante más de 12 años de experiencia profesional. En general, la revisión resalta la interrelación en las actividades de cada segmento corporal con otros y no como elementos aislados, así como la producción de eventos en común desde lo mecánico pero con propósitos diferentes desde lo funcional.

Genotipificación de HLA-B en pacientes colombianos afectados por el síndrome Stevens-Johnson y la Necrólisis Epidérmica Tóxica

Las reacciones alérgicas a medicamentos cutáneas severas (RAM) como el Síndrome Stevens Johnson (SJS) y la Necrólisis Epidérmica Tóxica (NET),caracterizadas por exantema, erosión de la piel y las membranas mucosas, flictenas, desprendimiento de la piel secundario a la muerte de queratinocitos y compromiso ocular. Son infrecuentes en la población pero con elevada morbi-mortalidad, se presentan luego de la administración de diferentes fármacos. En Asia se ha asociado el alelo HLA-B*15:02 como marcador genético para SJS. En Colombia no hay datos de la incidencia de estas RAM, ni de la relación con medicamentos específicos o potenciales y tampoco estudios de aproximación genómica de genes de susceptibilidad.

Verificación del impacto de la educación sexual en adolescentes en la consulta externa de dos IPS de Bogotá

En este estudio se realizó una encuesta con el fin de evidenciar el conocimiento y la práctica de la Educación Sexual en adolescentes que acudieron al servicio de consulta externa de Medicina General en dos Instituciones Prestadoras de Servicios de Salud (IPS) de la ciudad de Bogotá, una de régimen contributivo y otra de régimen subsidiado. Se realizó un estudio observacional, descriptivo, de corte transversal, a 100 adolescentes, mujeres y hombres, a través de la aplicación de un instrumento prediseñado con un contenido de 17 preguntas donde se indagó acerca de: planificación familiar, conducta sexual, educación sexual, embarazo adolescente y conductas de riesgo en adolescentes. En relación al régimen de aseguramiento en salud que tenían los adolescentes, las diferencias encontradas en sus respuestas fueron a nivel de: educación sexual recibida, acceso a los servicios de planificación familiar de las Empresas Promotoras de Salud (EPS), presencia de embarazo adolescente y consumo de alcohol asociado a la práctica de relaciones sexuales. Tras el análisis de la información obtenida con la aplicación de la encuesta, se concluye que es indispensable crear en las instituciones educativas públicas y privadas de la ciudad de Bogotá, una nueva herramienta metodológica a través de la cual se realice promoción de la salud y refuerzo de prácticas protectoras en educación sexual para adolescentes, pues persiste desconocimiento de la misma.

Síntomas respiratorios y neumoconiosis por polvo de carbón diagnosticada radiológicamente, en los trabajadores de minería subterránea en Boyacá en el año 2014

Introducción Las neumoconiosis son un grupo de enfermedades respiratorias ocupacionales, debidas a la acumulación de polvo en los pulmones. Colombia pese a ser un país minero, no cuenta con datos oficiales sobre la prevalencia de la neumoconiosis que permitan implementar medidas preventivas para evitar el desarrollo de enfermedades asociadas a la explotación minera y que disminuyan la incidencia y prevalencia de la neumoconiosis. Objetivos Determinar la prevalencia de neumoconiosis a partir del diagnóstico radiológico y describir síntomas respiratorios referidos por los trabajadores de las minas subterráneas de carbón en el departamento de Boyacá. Materiales y métodos Se realizó un estudio descriptivo de corte transversal en 232 trabajadores de minería subterránea del departamento de Boyacá; teniendo como fuente de información los datos obtenidos en el proyecto “Evaluación de la exposición a polvo de carbón en tres departamentos de Colombia, 2012-2015”, financiado por el Instituto Nacional de Salud, Universidad de Los Andes, la Universidad del Rosario, Positiva ARL y Colciencias. El análisis de los datos del estudio se realizó a través del software Stata versión 11. Resultados El 100% de la población estudio fueron de sexo masculino. La mediana para la edad fue de 40.5 años (20 – 73). La labor más comúnmente desempañada por los mineros fue: picadores 168 (72,41%). Los síntomas respiratorios más frecuentemente encontrados en este estudio fueron expectoración y tos. En cuanto a expectoración fue más frecuente en la mañana durante el invierno: 66.38% (154) y la tos de día o de noche durante el invierno: 53.88% (125). Para el hábito de fumar el 17.67% fumaba al momento del estudio. En 69 mineros (29.74%) se encontraron anormalidades parenquimatosas en la Radiografía de Tórax.