Applied mathematical problem solving, modelling, applications, and links to other subjects

The paper will consist of three parts. In part I we shall present some background considerations which are necessary as a basis for what follows. We shall try to clarify some basic concepts and notions, and we shall collect the most important arguments (and related goals) in favour of problem solving, modelling and applications to other subjects in mathematics instruction. In the main part II we shall review the present state, recent trends, and prospective lines of development, both in empirical or theoretical research and in the practice of mathematics instruction and mathematics education, concerning (applied) problem solving, modelling, applications and relations to other subjects. In particular, we shall identify and discuss four major trends: a widened spectrum of arguments, an increased globality, an increased unification, and an extended use of computers. In the final part III we shall comment upon some important issues and problems related to our topic.

2D-3D Rigid-Body Registration of X-Ray Fluoroscopy and CT Images

The registration of pre-operative volumetric datasets to intra- operative two-dimensional images provides an improved way of verifying patient position and medical instrument loca- tion. In applications from orthopedics to neurosurgery, it has a great value in maintaining up-to-date information about changes due to intervention. We propose a mutual information- based registration algorithm to establish the proper align- ment. For optimization purposes, we compare the perfor- mance of the non-gradient Powell method and two slightly di erent versions of a stochastic gradient ascent strategy: one using a sparsely sampled histogramming approach and the other Parzen windowing to carry out probability density approximation. Our main contribution lies in adopting the stochastic ap- proximation scheme successfully applied in 3D-3D registra- tion problems to the 2D-3D scenario, which obviates the need for the generation of full DRRs at each iteration of pose op- timization. This facilitates a considerable savings in compu- tation expense. We also introduce a new probability density estimator for image intensities via sparse histogramming, de- rive gradient estimates for the density measures required by the maximization procedure and introduce the framework for a multiresolution strategy to the problem. Registration results are presented on uoroscopy and CT datasets of a plastic pelvis and a real skull, and on a high-resolution CT- derived simulated dataset of a real skull, a plastic skull, a plastic pelvis and a plastic lumbar spine segment.

Los usos políticos del lenguaje y el problema del discurso de género: caso la despenalización del aborto en Colombia

Este trabajo se centra en el análisis del discurso político y desde allí analiza la problemática que tiene el aborto en Colombia, con la intencionalidad de permitir a las mujeres decidir sobre su cuerpo sin que sean notablemente estigmatizadas y penalizadas por llevar a cabo una práctica que desde ciertos puntos de vista debe ser permitida para respetar los derechos de las mujeres. En ese sentido, la despenalización del aborto en Colombia se permite en tres casos específicos, por violación, peligro para la vida de la mujer o malformaciones en el feto; bajo estas premisas que han pasado por una evolución discursiva, que no sólo ha afectado a las mujeres, sino a la sociedad, ya que el problema se ha acrecentado y se ha convertido también, en un problema de salud pública. Es así, que desde autores como Bourdieu, Butler y Austin, se crean actos de palabra que desprenden el cuerpo de su lenguaje, crea fuerza en él y permiten acciones que aumenten el posicionamiento de las mujeres en la lucha reivindicatoria que les permita decidir qué hacer con su cuerpo.

Comparación entre los pacientes con diagnóstico clínico de EPOC vs los confirmados por Espirometría en un hospital de segundo nivel en Bogotá DC, 2011

Introducción: La enfermedad pulmonar obstructiva crónica (EPOC), está caracterizada por la limitación del flujo aéreo, de forma progresiva y casi irreversible, asociada a la reacción inflamatoria atribuida a diferentes factores, principalmente a la exposición al humo de tabaco. Es considerada un problema de salud pública en Colombia y en el mundo, con un aumento acelerado de la condición crónica en la actualidad. Objetivo: Identificar las diferencias sociodemográficas, clínicas y de tratamiento, entre los pacientes con diagnóstico clínico y espirométricos de EPOC vs los pacientes con diagnóstico clínico y descartados por espirometría en el Hospital de Suba. Material y Métodos: Estudio observacional, descriptivo, retrospectivo como un componente exploratorio para comparar los grupos con diagnóstico de EPOC clínico y confirmado o descartado por espirometría, entre Enero y Agosto del 2011. Se utilizó estadística descriptiva para calcular las medidas de tendencia central, los datos cuantitativos se expresaron como la media de la variable ± desviación estándar, y los cualitativos como porcentaje, la t de Student para analizar diferencia de las variables cuantitativas de medias entre grupos y la prueba de Pearson para analizar la relación entre los datos cualitativos para aquellos con valores esperados menores a 5 se aplicó test exacto de Fisher, tuvimos en cuenta un α de 0.05 para el análisis bivariado y medidas de asociación. Todos los análisis se realizaron con el paquete estadístico SPSS 19,0 Versión corporativa. Resultados: De los 398 pacientes, solo 287 cumplían con criterios de inclusión. El promedio de edad del total de los pacientes fue de 70,29 + 11,18 años, y 59,5% de la población fue de sexo femenino. Del total de pacientes evaluados, 171 pacientes (59.6%) se descartó el diagnóstico de EPOC (VEF1/ VEC > 0,70). Al comparar los grupos de pacientes a los que se les confirmo el diagnóstico de EPOC contras los descartados por espirometría se encontró que no hay diferencias estadísticamente significativas entre la edad; en los pacientes con EPOC predomino el sexo femenino (p 0.02); en los factores de riesgo existe clara asociación entre EPOC y la exposición a humo de leña (p <0.001), y en cuanto al tabaquismo solo se encontró asociación con ex fumador (p 0,011). Para analizar las diferencias en el tratamiento se estratifico por las posible combinaciones de inhaladores con o sin teofilina, encontrando una diferencia estadísticamente significativa para los tratamientos de tres inhaladores (p 0,015), dos inhaladores + teofilina (p 0,05), tres inhaladores + teofilina (p <0.001), y en los pacientes no tratados (p <0,001).

Presión arterial en preescolares de la localidad de Usaquén en Bogotá

Introducción: La hipertensión arterial es un problema de salud pública tanto en países industrializados como en vía de desarrollo. Su prevalencia en la infancia viene en aumento por lo que es relevante determinarla en niños preescolares a nivel local. Objetivo: Determinar la prevalencia de hipertensión arterial en niños de tres a cinco años de una cohorte de 14 hogares infantiles del ICBF de la localidad de Usaquén en Bogotá. Materiales y métodos: Se realizó un estudio de corte transversal analítico, utilizando la base de datos de un ensayo aleatorizado y controlado del año 200913, y se evaluaron las cifras de tensión arterial de acuerdo a sexo, edad, talla y su correlación con el IMC con un nivel de confianza del 95% y precisión del 1%. Se calcularon las medias, desviaciones estándar, percentiles y prevalencia. Resultados: Se obtuvo una muestra de 1035 casos, encontrándose una prevalencia de 4,5% de HTA sistólica, 10,4% de diastólica, ambas en estadio I; teniendo en cuenta tanto sistólica como diastólica, fue de 11,6% en estadio I. Se determinaron los valores de presión arterial sistólica y diastólica en cuartiles de acuerdo a edad, sexo y talla. El coeficiente de correlación entre el IMC y los niveles de presión arterial sistólica y diastólica fueron de 0.0992 y 0.0362 respectivamente. Conclusión: La prevalencia de HTA general fue de 11,6%, predominando la diastólica en estadio I en niños preescolares. No se encontró correlación entre el IMC y las cifras de tensión arterial sistólica y diastólica.

Pregnancy in adolescents as a problem to 14 – 19 year olds in Nocaima (Cundinamarca)

Adolescent pregnancy is a current problem which raises concern due to its individual, familiar and collective consequences. Fifteen million adolescents give birth each year in the world. Abortion is the preferred option used in unwanted pregnancies. Adolescent pregnancy is frequent in Nocaima, Cundinamarca and is a community concern in this small town initiating its process of becoming a healthy municipality. As such, the community has highlighted this problem to be studied and submitted to intervention to promote a free and responsible sexuality decreasing unwanted adolescent pregnancies. Objective: To find data on contraception, pregnancy and related factors in selected adolescents therefore, improving current incomplete information. Methods: Descriptive observational study with survey application on 226 female 14 to 19 year old students from three high school facilities in Nocaima including 8th to 11th graders. Results: 88.9% of the participants were between 14 and 17 years of age. 66.8% of the adolescents claim to use correctly contraceptive methods and 28.8% have had sexual intercourse with an average initiation at age 15. 11.1% have been pregnant once in their lives and of these 57.1 % ended in induced abortion and 66.8% were school dropouts. Conclusions: After having implemented an educational campaign on healthy sex and reproductive behaviors we view adolescent pregnancy as a public health problem which is preventable and related to the deficit of social and family support as well as weakness in individual decision making.

Las adicciones a la luz del psicoanálisis, una revisión de literatura

El presente trabajo de grado es una revisión de la literatura que permite hacer un recorrido desde el psicoanálisis acerca de la compleja problemática de las adicciones. Para ello, se revisaron las bases de datos PepWeb, Ebsco, y Jstor, revisando las posiciones del psicoanálisis freudiano, lacaniano y otras corrientes psicoanalíticas respondiendo a las siguientes preguntas de investigación: (a) ¿Cómo se comprenden las adicciones desde un marco de referencia psicoanalítico? (b) ¿Cómo –desde la teoría freudiana y la teoría lacaniana - se aborda la comprensión de la adicción? (c) ¿Qué dice el psicoanálisis contemporáneo sobre ésta problemática? Se abordan temas como la concepción de una adicción desde la perspectiva de Freud y Lacan hasta psicoanalistas contemporáneos, el rol que juega el goce en la adicción y, finalmente, el complejo debate incipiente sobre la legalidad del tóxico. Se encontró que es un campo de constante publicación y es necesario que los clínicos y los psicoanalistas aborden este campo de estudio clínico permanentemente y sigan produciendo investigaciones sobre el fenómeno.

La pelota no se mancha: Un estudio histórico sobre el desarrollo y la política en FIFA

Esta investigación se centra en la Fédération Internationale de Football Association (FIFA) como organización política. Intenta responder dos interrogantes primordiales: 1) ¿cómo la FIFA ha constituido el poder que tiene actualmente y, así, hacerse del monopolio indiscutido del fútbol? Y 2) ¿cómo ha cambiado en el tiempo la política interna de FIFA y su vínculo con la política internacional? Para lograr esto, se realiza un estudio histórico, basado principalmente en documentos, que intenta caracterizar y analizar los cambios de la organización en el tiempo. Se enfatizan las últimas dos presidencias de FIFA, de João Havelange y Joseph Blatter, como casos de estudio.

Counterpoise-corrected geometries and harmonic frequencies of N-body clusters: application to (HF)n (n=3,4)

A study was conducted on the methods of basis set superposition error (BSSE)-free geometry optimization and frequency calculations in clusters larger than a dimer. In particular, three different counterpoise schemes were critically examined. It was shown that the counterpoise-corrected supermolecule energy can be easily obtained in all the cases by using the many-body partitioning of energy

Optimització del procés productiu d'engreixament porcí. Un enfocament operatiu

Aquest treball de tesis doctoral tracta de la Optimització de la fase d'engreix. L'objectiu és determinar les condicions d'enviament a sacrifici d'un lot d'animals des d'un punt de vista operatiu. En primer lloc es fa una anàlisi de la cadena de producció de carn porcina, resaltant-ne els canvis del sector que han influit en la fase d'engreixament. La conclusió d'aquesta anàlisi és el plantejament d'un model per prendre decisions degut al canvi de paradigma que s'evidencia: els productors de porcs en la fase d'engreix cal que orientin la gestió del paràmetres operatius i els productes finals a les exigències i gustos dels seus clients. Seguidament, es presenta el sistema d'ajut a la decisió basat en un model biològic que explica l'evolució de les variables productives (pes i consum de pinso). A més també prediu les variables associades a característiques de la canal, com són el percentatge de magre, la proporció de peces, el rendiment i el greix intramuscular. El sistema té en compte tres mercats de carn porcina alternatius: 1) basat en pes viu, 2) basat en mèrits de la canal (percentatge de magre) y 3) basat en el valor de les peces nobles resultants de l'especejament de l'animal. L'objetiu del sistema és determinar la millor estratègia d'enviament per a cadascun dels genotips que s'han estudiat (alternatives de producció) depenent del mercat on seran enviats els animals. A més, també ha estat estudiat l'efecte de la variabilitat biològica dels animals dins del lot sobre els valors econòmics. També s'ha considerat l'opció d'enviar els animals en diverses etapes per tal d'homogeneitzar el pes dels animals enviats. Aquest problema ha estat estudiat seguint l'enfocament de programació dinàmica. En els darrers capítols es presenten quatre aplicacions del model que s'han desenvolupat al llarg del treball. En un futur els mercats de carn porcina tindran la tendència a ser més definits, per tant la producció en la fase d'engreixament porcí hauria d'integrar i tenir en compte les demandes i les exigències del consumidor.

An approach to coded structured light to obtain three dimensional information

The human visual ability to perceive depth looks like a puzzle. We perceive three-dimensional spatial information quickly and efficiently by using the binocular stereopsis of our eyes and, what is mote important the learning of the most common objects which we achieved through living. Nowadays, modelling the behaviour of our brain is a fiction, that is why the huge problem of 3D perception and further, interpretation is split into a sequence of easier problems. A lot of research is involved in robot vision in order to obtain 3D information of the surrounded scene. Most of this research is based on modelling the stereopsis of humans by using two cameras as if they were two eyes. This method is known as stereo vision and has been widely studied in the past and is being studied at present, and a lot of work will be surely done in the future. This fact allows us to affirm that this topic is one of the most interesting ones in computer vision. The stereo vision principle is based on obtaining the three dimensional position of an object point from the position of its projective points in both camera image planes. However, before inferring 3D information, the mathematical models of both cameras have to be known. This step is known as camera calibration and is broadly describes in the thesis. Perhaps the most important problem in stereo vision is the determination of the pair of homologue points in the two images, known as the correspondence problem, and it is also one of the most difficult problems to be solved which is currently investigated by a lot of researchers. The epipolar geometry allows us to reduce the correspondence problem. An approach to the epipolar geometry is describes in the thesis. Nevertheless, it does not solve it at all as a lot of considerations have to be taken into account. As an example we have to consider points without correspondence due to a surface occlusion or simply due to a projection out of the camera scope. The interest of the thesis is focused on structured light which has been considered as one of the most frequently used techniques in order to reduce the problems related lo stereo vision. Structured light is based on the relationship between a projected light pattern its projection and an image sensor. The deformations between the pattern projected into the scene and the one captured by the camera, permits to obtain three dimensional information of the illuminated scene. This technique has been widely used in such applications as: 3D object reconstruction, robot navigation, quality control, and so on. Although the projection of regular patterns solve the problem of points without match, it does not solve the problem of multiple matching, which leads us to use hard computing algorithms in order to search the correct matches. In recent years, another structured light technique has increased in importance. This technique is based on the codification of the light projected on the scene in order to be used as a tool to obtain an unique match. Each token of light is imaged by the camera, we have to read the label (decode the pattern) in order to solve the correspondence problem. The advantages and disadvantages of stereo vision against structured light and a survey on coded structured light are related and discussed. The work carried out in the frame of this thesis has permitted to present a new coded structured light pattern which solves the correspondence problem uniquely and robust. Unique, as each token of light is coded by a different word which removes the problem of multiple matching. Robust, since the pattern has been coded using the position of each token of light with respect to both co-ordinate axis. Algorithms and experimental results are included in the thesis. The reader can see examples 3D measurement of static objects, and the more complicated measurement of moving objects. The technique can be used in both cases as the pattern is coded by a single projection shot. Then it can be used in several applications of robot vision. Our interest is focused on the mathematical study of the camera and pattern projector models. We are also interested in how these models can be obtained by calibration, and how they can be used to obtained three dimensional information from two correspondence points. Furthermore, we have studied structured light and coded structured light, and we have presented a new coded structured light pattern. However, in this thesis we started from the assumption that the correspondence points could be well-segmented from the captured image. Computer vision constitutes a huge problem and a lot of work is being done at all levels of human vision modelling, starting from a)image acquisition; b) further image enhancement, filtering and processing, c) image segmentation which involves thresholding, thinning, contour detection, texture and colour analysis, and so on. The interest of this thesis starts in the next step, usually known as depth perception or 3D measurement.

Studies of dynamics of physical agent ecosystems

This thesis addresses the problem of learning in physical heterogeneous multi-agent systems (MAS) and the analysis of the benefits of using heterogeneous MAS with respect to homogeneous ones. An algorithm is developed for this task; building on a previous work on stability in distributed systems by Tad Hogg and Bernardo Huberman, and combining two phenomena observed in natural systems, task partition and hierarchical dominance. This algorithm is devised for allowing agents to learn which are the best tasks to perform on the basis of each agent's skills and the contribution to the team global performance. Agents learn by interacting with the environment and other teammates, and get rewards from the result of the actions they perform. This algorithm is specially designed for problems where all robots have to co-operate and work simultaneously towards the same goal. One example of such a problem is role distribution in a team of heterogeneous robots that form a soccer team, where all members take decisions and co-operate simultaneously. Soccer offers the possibility of conducting research in MAS, where co-operation plays a very important role in a dynamical and changing environment. For these reasons and the experience of the University of Girona in this domain, soccer has been selected as the test-bed for this research. In the case of soccer, tasks are grouped by means of roles. One of the most interesting features of this algorithm is that it endows MAS with a high adaptability to changes in the environment. It allows the team to perform their tasks, while adapting to the environment. This is studied in several cases, for changes in the environment and in the robot's body. Other features are also analysed, especially a parameter that defines the fitness (biological concept) of each agent in the system, which contributes to performance and team adaptability. The algorithm is applied later to allow agents to learn in teams of homogeneous and heterogeneous robots which roles they have to select, in order to maximise team performance. The teams are compared and the performance is evaluated in the games against three hand-coded teams and against the different homogeneous and heterogeneous teams built in this thesis. This section focuses on the analysis of performance and task partition, in order to study the benefits of heterogeneity in physical MAS. In order to study heterogeneity from a rigorous point of view, a diversity measure is developed building on the hierarchic social entropy defined by Tucker Balch. This is adapted to quantify physical diversity in robot teams. This tool presents very interesting features, as it can be used in the future to design heterogeneous teams on the basis of the knowledge on other teams.

Między językiem a światem. O poezji Krystyny Miłobędzkiej

Wydział Filologii Polskiej i Klasycznej: Instytut Filologii Polskiej

Collaboration between infection control and occupational health in three continents: a success story with international impact

Globalization has been accompanied by the rapid spread of infectious diseases, and further strain on working conditions for health workers globally. Post-SARS, Canadian occupational health and infection control researchers got together to study how to better protect health workers, and found that training was indeed perceived as key to a positive safety culture. This led to developing information and communication technology (ICT) tools. The research conducted also showed the need for better workplace inspections, so a workplace audit tool was also developed to supplement worker questionnaires and the ICT. When invited to join Ecuadorean colleagues to promote occupational health and infection control, these tools were collectively adapted and improved, including face-to-face as well as on-line problem-based learning scenarios. The South African government then invited the team to work with local colleagues to improve occupational health and infection control, resulting in an improved web-based health information system to track incidents, exposures, and occupational injury and diseases. As the H1N1 pandemic struck, the online infection control course was adapted and translated into Spanish, as was a novel skill-building learning tool that permits health workers to practice selecting personal protective equipment. This tool was originally developed in collaboration with the countries from the Caribbean region and the Pan American Health Organization (PAHO). Research from these experiences led to strengthened focus on building capacity of health and safety committees, and new modules are thus being created, informed by that work. The products developed have been widely heralded as innovative and interactive, leading to their inclusion into “toolkits” used internationally. The tools used in Canada were substantially improved from the collaborative adaptation process for South and Central America and South Africa. This international collaboration between occupational health and infection control researchers led to the improvement of the research framework and development of tools, guidelines and information systems. Furthermore, the research and knowledge-transfer experience highlighted the value of partnership amongst Northern and Southern researchers in terms of sharing resources, experiences and knowledge.

The Influence of Body Condition on the Stopover Ecology of Least Sandpipers in the Lower Mississippi Alluvial Valley during Fall Migration

Many shorebirds are long-distance migrants and depend on the energy gained at stopover sites to complete migration. Competing hypotheses have described strategies used by migrating birds; the energy-selection hypothesis predicts that shorebirds attempt to maximize energy gained at stopover sites, whereas the time-selection hypothesis predicts that shorebirds attempt to minimize time spent at stopover sites. The energy- and time-selection hypotheses both predict that birds in better condition will depart sites sooner. However, numerous studies of stopover duration have found little support for this prediction, leading to the suggestion that migrating birds operate under energy and time constraints for only a small portion of the migratory season. During fall migration 2002, we tested the prediction that birds in better condition depart stopover sites sooner by examining the relationship between stopover duration and body condition for migrating Least Sandpipers (Calidris minutilla) at three stopover sites in the Lower Mississippi Alluvial Valley. We also tested the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team that shorebirds stay in the Mississippi Valley for 10 d. The assumption of 10 d was used to estimate the amount of habitat required by shorebirds in the Mississippi Valley during fall migration; a period longer than 10 d would increase the estimate of the amount habitat required. We used multiple-day constancy models of apparent survival and program MARK to estimate stopover duration for 293 individually color-marked and resighted Least Sandpipers. We found that a four-day constancy interval and a site x quadratic time trend interaction term best modeled apparent survival. We found only weak support for body condition as a factor explaining length of stopover duration, which is consistent with findings from similar work. Stopover duration estimates were 4.1 d (95% CI = 2.8–6.1) for adult Least Sandpipers at Bald Knob National Wildlife Refuge, Arkansas, 6.5 d (95% CI = 4.9–8.7) for adult and 6.1 d (95% CI =4.2–9.1) for juvenile Least Sandpipers at Yazoo National Wildlife Refuge, Mississippi, and 6.9 d (95% CI = 5.5–8.7) for juvenile Least Sandpipers at Morgan Brake National Wildlife Refuge, Mississippi. Based on our estimates of stopover duration and the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team, there is sufficient habitat in the lower Mississippi Valley to support shorebirds during fall migration.