The Freedom SOLO bovine pericardial stentless valve

Abstract: The third-generation bovine pericardium Freedom SOLO (FS) stentless valve emerged in 2004 as a modified version of the Pericarbon Freedom stentless valve and as a very attractive alternative to stented bioprostheses. The design, choice of tissue, and anticalcification treatment fulfill most, if not all, requirements for an ideal valve substitute. The FS combines the single-suture, subcoronary implantation technique with the latest-generation bovine pericardial tissue and novel anticalcification treatment. The design allows imitation of the native healthy valve through unrestricted adaption to the patient's anatomy, reproducing a normal valve/root complex. However, despite hemodynamic performance superior to stented valves, we are approaching a critical observation period as superior durability, freedom from structural valve deterioration, and nonstructural failure has not been proven as expected. However, optimal performance and freedom from structural valve deterioration depend on correct sizing and perfect symmetric implantation, to ensure low leaflet stress. Any malpositioning can lead to tissue fatigue over time. Furthermore, the potential for better outcomes depends on optimal patient selection and observance of the limitations for the use of stentless valves, particularly for the FS. Clearly, stentless valve implantation techniques are less reproducible and standardized, and require surgeon-dependent experience and skill. Regardless of whether or not stentless valve durability surpasses third-generation stented bioprostheses, they will continue to play a role in the surgical repertoire. This review intends to help practitioners avoid pitfalls, observe limitations, and improve patient selection for optimal long-term outcome with the attractive FS stentless valve.

Development of a diagnostic online tool system for Swiss sport psychology practitioners

Psychological assessment is a central component of applied sport psychology. Despite obvious and well-documented advantages of diagnostic online tools, there is a lack of a system for such tools for sport psychologists so far in Switzerland. Having the most frequently used questionnaires available online in one single tool for all listed Swiss sport psychologists would make the work of practitioners a lot easier and less time consuming. Therefore, the main goal of this project is to develop a diagnostic online tool system with the possibility to make available different questionnaires often used in sport psychology. Furthermore, we intend to survey status and use of this diagnostic online tool system and the questionnaires by Swiss sport psychologists. A specific challenge is to limit the access to qualified sport psychologists and to secure the confidentiality for the client. In particular, approved sport psychologists get an individual code for each of their athletes for the required questionnaire. With the help of this code, athletes can access the test via a secure website at any place of the world. As soon as they complete and submit the online questionnaire, analysed and interpreted data reach the sport psychologist via E-Mail, which is timesaving and easy applicable for the sport psychologist. Furthermore, data are available for interpretation with athletes and documentation of individual development over time is possible. Later on, completed and anonymised questionnaires will be collected and analysed. Bigger number of collected data give more insight in the psychometric properties, thus helping to improve and further develop the questionnaires. In this presentation, we demonstrate the tool and its feasibility using the German version of the Test of Performance Strategies (TOPS, Schmid et al., 2010). To conclude, this diagnostic online tool system offers new possibilities for sport psychologists working as practitioner.

"I understood what she meant when she said '21st century medicine'": A qualitative analysis of patient responses for plans for colorectal cancer screening following a recommendation from their physician

Although physician recommendation has been significantly associated with colorectal cancer screening (CRCS), it still does not motivate all patients to get CRCS. Although improved physician recommendation for CRCS has been shown to increase patient CRCS screening, questions remain about what elements of that discussion may lead to screening. The objective of this study is to describe patients' perceptions and interpretations about their physician's recommendation for CRCS during their annual wellness exam. A subset of patients (n=51) participating in a supplement study of a behavioral intervention trial designed to increase CRCS completed a follow-up, open-ended interview two to four weeks after their annual wellness visit. Using qualitative methods, transcripts of these interviews were analyzed. Findings suggest that most patients would follow their physician's recommendation for CRCS despite not engaging in much discussion. Patients may refrain from CRCS discussion because of a commitment to CRCS, awareness of screening guidelines, and trust in physician's honesty and beneficence. Yet many patients left their wellness exams with questions, refraining because of future plans to consult with their physicians, perceived time constraints or a lack of a patient-physician relationship. If patients are leaving their wellness exams with unanswered questions, interventions should prepare physicians for patient reticence, teaching physicians how to assure patients that CRCS is a primary care activity where all questions and concerns, including cost and scheduling, may be resolved.^

A methodology for granularity-based control of parallelism in logic programs

Several types of parallelism can be exploited in logic programs while preserving correctness and efficiency, i.e. ensuring that the parallel execution obtains the same results as the sequential one and the amount of work performed is not greater. However, such results do not take into account a number of overheads which appear in practice, such as process creation and scheduling, which can induce a slow-down, or, at least, limit speedup, if they are not controlled in some way. This paper describes a methodology whereby the granularity of parallel tasks, i.e. the work available under them, is efficiently estimated and used to limit parallelism so that the effect of such overheads is controlled. The run-time overhead associated with the approach is usually quite small, since as much work is done at compile time as possible. Also,a number of run-time optimizations are proposed. Moreover, a static analysis of the overhead associated with the granularity control process is performed in order to decide its convenience. The performance improvements resulting from the incorporation of grain size control are shown to be quite good, specially for systems with medium to large parallel execution overheads.

Towards granularity based control of parallelism in logic programs

Several types of parallelism can be exploited in logic programs while preserving correctness and efficiency, i.e. ensuring that the parallel execution obtains the same results as the sequential one and the amount of work performed is not greater. However, such results do not take into account a number of overheads which appear in practice, such as process creation and scheduling, which can induce a slow-down, or, at least, limit speedup, if they are not controlled in some way. This paper describes a methodology whereby the granularity of parallel tasks, i.e. the work available under them, is efficiently estimated and used to limit parallelism so that the effect of such overheads is controlled. The run-time overhead associated with the approach is usually quite small, since as much work is done at compile time as possible. Also, a number of run-time optimizations are proposed. Moreover, a static analysis of the overhead associated with the granularity control process is performed in order to decide its convenience. The performance improvements resulting from the incorporation of grain size control are shown to be quite good, specially for systems with médium to large parallel execution overheads.

Task granularity analysis in logic programs

While logic programming languages offer a great deal of scope for parallelism, there is usually some overhead associated with the execution of goals in parallel because of the work involved in task creation and scheduling. In practice, therefore, the "granularity" of a goal, i.e. an estimate of the work available under it, should be taken into account when deciding whether or not to execute a goal concurrently as a sepárate task. This paper describes a method for estimating the granularity of a goal at compile time. The runtime overhead associated with our approach is usually quite small, and the performance improvements resulting from the incorporation of grainsize control can be quite good. This is shown by means of experimental results.

Metodología para maximizar la rentabilidad de una terminal marítima de contenedores a través de la optimización de su grado de automatización

Son generalmente aceptadas las tendencias actuales de maximización de la automatización para la adaptación de las terminales marítimas de contenedores a las cada vez mayores exigencias competitivas del negocio de transporte de contenedores. En esta investigación, se somete a consideración dichas tendencias a través de un análisis que tenga en cuenta la realidad global de la terminal pero también su propia realidad local que le permita aprovechar sus fortalezas y minimizar sus debilidades en un mercado continuamente en crecimiento y cambio. Para lo cual se ha desarrollado un modelo de análisis en el que se tengan en cuenta los parámetros técnicos, operativos, económicos y financieros que influyen en el diseño de una terminal marítima de contenedores, desde su concepción como ente dependiente para generar negocio, todos ellos dentro de un perímetro definido por el mercado del tráfico de contenedores así como las limitaciones físicas introducidas por la propia terminal. Para la obtención de dicho modelo ha sido necesario llevar a cabo un proceso de estudio del contexto actual del tráfico de contenedores y su relación con el diseño de las terminales marítimas, así como de las metodologías propuestas hasta ahora por los diferentes autores para abordar el proceso de dimensionamiento y diseño de la terminal. Una vez definido el modelo que ha de servir de base para el diseño de una terminal marítima de contenedores desde un planteamiento multicriterio, se analiza la influencia de las diversas variables explicativas de dicho modelo y se cuantifica su impacto en los resultados económicos, financieros y operativos de la terminal. Un paso siguiente consiste en definir un modelo simplificado que vincule la rentabilidad de una concesión de terminal con el tráfico esperado en función del grado de automatización y del tipo de terminal. Esta investigación es el fruto del objetivo ambicioso de aportar una metodología que defina la opción óptima de diseño de una terminal marítima de contenedores apoyada en los pilares de la optimización del grado de automatización y de la maximización de la rentabilidad del negocio que en ella se desarrolla. It is generally accepted current trends in automation to maximize the adaptation of maritime container terminals to the growing competitive demands of the business of container shipping. In this research, is submitted to these trends through an analysis taking into account the global reality of the terminal but also their own local reality it could exploit its strengths and minimize their weaknesses in a market continuously growing and changing. For which we have developed a model analysis that takes into account the technical, operational, financial and economic influence in the design of a container shipping terminal, from its conception as being dependent to generate business, all within a perimeter defined by the market of container traffic and the physical constraints introduced by the terminal. To obtain this model has been necessary to conduct a study process in the current context of container traffic and its relation to the design of marine terminals, as well as the methodologies proposed so far by different authors to address the process sizing and design of the terminal. Having defined the model that will serve as the basis for the design for a container shipping terminal from a multi-criteria approach, we analyze the influence of various explanatory variables of the model and quantify their impact on economic performance, financial and operational of the terminal. A next step is to define a simplified model that links the profitability of a terminal concession with traffic expected on the basis of the degree of automation and the kind of terminal. This research is the result of the ambitious target of providing a methodology to define the optimal choice of designing a container shipping terminal on the pillars of automation optimizing and maximizing the profitability of the business that it develops.

System Engineering Approach to Initial Design of LEO Remote Sensing Missions

The satellite remote sensing missions are essential for long-term research around the condition of the earth resources and environment. On the other hand, in recent years the application of microsatellites is of interest in many space programs for their less cost and response time. In microsatellite remote sensing missions there are tight interrelations between different requirements such as orbital altitude, revisit time, mission life and spatial resolution. Also, all of these requirements can affect the whole system level design characteristics. In this work, the remote sensing microsatellite sizing process is divided into three major design disciplines; a) orbit design, b) payload sizing and c) bus sizing. Finally, some specific design cases are investigated inside the design space for evaluating the effect of different design variables on the satellite total mass. Considering the results of the work, it is concluded that applying a systematic approach at the initial design phase of such projects provides a good insight to the not clearly seen interactions inside their highly extended design space

Multidisciplinary Design Optimization Application to Conceptual Design of University-class Microsatellite Projects

Esta tesis se ha realizado en el contexto del proyecto UPMSat-2, que es un microsatélite diseñado, construido y operado por el Instituto Universitario de Microgravedad "Ignacio Da Riva" (IDR / UPM) de la Universidad Politécnica de Madrid. Aplicación de la metodología Ingeniería Concurrente (Concurrent Engineering: CE) en el marco de la aplicación de diseño multidisciplinar (Multidisciplinary Design Optimization: MDO) es uno de los principales objetivos del presente trabajo. En los últimos años, ha habido un interés continuo en la participación de los grupos de investigación de las universidades en los estudios de la tecnología espacial a través de sus propios microsatélites. La participación en este tipo de proyectos tiene algunos desafíos inherentes, tales como presupuestos y servicios limitados. Además, debido al hecho de que el objetivo principal de estos proyectos es fundamentalmente educativo, por lo general hay incertidumbres en cuanto a su misión en órbita y cargas útiles en las primeras fases del proyecto. Por otro lado, existen limitaciones predeterminadas para sus presupuestos de masa, volumen y energía, debido al hecho de que la mayoría de ellos están considerados como una carga útil auxiliar para el lanzamiento. De este modo, el costo de lanzamiento se reduce considerablemente. En este contexto, el subsistema estructural del satélite es uno de los más afectados por las restricciones que impone el lanzador. Esto puede afectar a diferentes aspectos, incluyendo las dimensiones, la resistencia y los requisitos de frecuencia. En la primera parte de esta tesis, la atención se centra en el desarrollo de una herramienta de diseño del subsistema estructural que evalúa, no sólo las propiedades de la estructura primaria como variables, sino también algunas variables de nivel de sistema del satélite, como la masa de la carga útil y la masa y las dimensiones extremas de satélite. Este enfoque permite que el equipo de diseño obtenga una mejor visión del diseño en un espacio de diseño extendido. La herramienta de diseño estructural se basa en las fórmulas y los supuestos apropiados, incluyendo los modelos estáticos y dinámicos del satélite. Un algoritmo genético (Genetic Algorithm: GA) se aplica al espacio de diseño para optimizaciones de objetivo único y también multiobjetivo. El resultado de la optimización multiobjetivo es un Pareto-optimal basado en dos objetivo, la masa total de satélites mínimo y el máximo presupuesto de masa de carga útil. Por otro lado, la aplicación de los microsatélites en misiones espaciales es de interés por su menor coste y tiempo de desarrollo. La gran necesidad de las aplicaciones de teledetección es un fuerte impulsor de su popularidad en este tipo de misiones espaciales. Las misiones de tele-observación por satélite son esenciales para la investigación de los recursos de la tierra y el medio ambiente. En estas misiones existen interrelaciones estrechas entre diferentes requisitos como la altitud orbital, tiempo de revisita, el ciclo de vida y la resolución. Además, todos estos requisitos puede afectar a toda las características de diseño. Durante los últimos años la aplicación de CE en las misiones espaciales ha demostrado una gran ventaja para llegar al diseño óptimo, teniendo en cuenta tanto el rendimiento y el costo del proyecto. Un ejemplo bien conocido de la aplicación de CE es la CDF (Facilidad Diseño Concurrente) de la ESA (Agencia Espacial Europea). Está claro que para los proyectos de microsatélites universitarios tener o desarrollar una instalación de este tipo parece estar más allá de las capacidades del proyecto. Sin embargo, la práctica de la CE a cualquier escala puede ser beneficiosa para los microsatélites universitarios también. En la segunda parte de esta tesis, la atención se centra en el desarrollo de una estructura de optimización de diseño multidisciplinar (Multidisciplinary Design Optimization: MDO) aplicable a la fase de diseño conceptual de microsatélites de teledetección. Este enfoque permite que el equipo de diseño conozca la interacción entre las diferentes variables de diseño. El esquema MDO presentado no sólo incluye variables de nivel de sistema, tales como la masa total del satélite y la potencia total, sino también los requisitos de la misión como la resolución y tiempo de revisita. El proceso de diseño de microsatélites se divide en tres disciplinas; a) diseño de órbita, b) diseño de carga útil y c) diseño de plataforma. En primer lugar, se calculan diferentes parámetros de misión para un rango práctico de órbitas helio-síncronas (sun-synchronous orbits: SS-Os). Luego, según los parámetros orbitales y los datos de un instrumento como referencia, se calcula la masa y la potencia de la carga útil. El diseño de la plataforma del satélite se estima a partir de los datos de la masa y potencia de los diferentes subsistemas utilizando relaciones empíricas de diseño. El diseño del subsistema de potencia se realiza teniendo en cuenta variables de diseño más detalladas, como el escenario de la misión y diferentes tipos de células solares y baterías. El escenario se selecciona, de modo de obtener una banda de cobertura sobre la superficie terrestre paralelo al Ecuador después de cada intervalo de revisita. Con el objetivo de evaluar las interrelaciones entre las diferentes variables en el espacio de diseño, todas las disciplinas de diseño mencionados se combinan en un código unificado. Por último, una forma básica de MDO se ajusta a la herramienta de diseño de sistema de satélite. La optimización del diseño se realiza por medio de un GA con el único objetivo de minimizar la masa total de microsatélite. Según los resultados obtenidos de la aplicación del MDO, existen diferentes puntos de diseños óptimos, pero con diferentes variables de misión. Este análisis demuestra la aplicabilidad de MDO para los estudios de ingeniería de sistema en la fase de diseño conceptual en este tipo de proyectos. La principal conclusión de esta tesis, es que el diseño clásico de los satélites que por lo general comienza con la definición de la misión y la carga útil no es necesariamente la mejor metodología para todos los proyectos de satélites. Un microsatélite universitario, es un ejemplo de este tipo de proyectos. Por eso, se han desarrollado un conjunto de herramientas de diseño para encarar los estudios de la fase inicial de diseño. Este conjunto de herramientas incluye diferentes disciplinas de diseño centrados en el subsistema estructural y teniendo en cuenta una carga útil desconocida a priori. Los resultados demuestran que la mínima masa total del satélite y la máxima masa disponible para una carga útil desconocida a priori, son objetivos conflictivos. En este contexto para encontrar un Pareto-optimal se ha aplicado una optimización multiobjetivo. Según los resultados se concluye que la selección de la masa total por satélite en el rango de 40-60 kg puede considerarse como óptima para un proyecto de microsatélites universitario con carga útil desconocida a priori. También la metodología CE se ha aplicado al proceso de diseño conceptual de microsatélites de teledetección. Los resultados de la aplicación del CE proporcionan una clara comprensión de la interacción entre los requisitos de diseño de sistemas de satélites, tales como la masa total del microsatélite y la potencia y los requisitos de la misión como la resolución y el tiempo de revisita. La aplicación de MDO se hace con la minimización de la masa total de microsatélite. Los resultados de la aplicación de MDO aclaran la relación clara entre los diferentes requisitos de diseño del sistema y de misión, así como que permiten seleccionar las líneas de base para el diseño óptimo con el objetivo seleccionado en las primeras fase de diseño. ABSTRACT This thesis is done in the context of UPMSat-2 project, which is a microsatellite under design and manufacturing at the Instituto Universitario de Microgravedad “Ignacio Da Riva” (IDR/UPM) of the Universidad Politécnica de Madrid. Application of Concurrent Engineering (CE) methodology in the framework of Multidisciplinary Design application (MDO) is one of the main objectives of the present work. In recent years, there has been continuing interest in the participation of university research groups in space technology studies by means of their own microsatellites. The involvement in such projects has some inherent challenges, such as limited budget and facilities. Also, due to the fact that the main objective of these projects is for educational purposes, usually there are uncertainties regarding their in orbit mission and scientific payloads at the early phases of the project. On the other hand, there are predetermined limitations for their mass and volume budgets owing to the fact that most of them are launched as an auxiliary payload in which the launch cost is reduced considerably. The satellite structure subsystem is the one which is most affected by the launcher constraints. This can affect different aspects, including dimensions, strength and frequency requirements. In the first part of this thesis, the main focus is on developing a structural design sizing tool containing not only the primary structures properties as variables but also the satellite system level variables such as payload mass budget and satellite total mass and dimensions. This approach enables the design team to obtain better insight into the design in an extended design envelope. The structural design sizing tool is based on the analytical structural design formulas and appropriate assumptions including both static and dynamic models of the satellite. A Genetic Algorithm (GA) is applied to the design space for both single and multiobejective optimizations. The result of the multiobjective optimization is a Pareto-optimal based on two objectives, minimum satellite total mass and maximum payload mass budget. On the other hand, the application of the microsatellites is of interest for their less cost and response time. The high need for the remote sensing applications is a strong driver of their popularity in space missions. The satellite remote sensing missions are essential for long term research around the condition of the earth resources and environment. In remote sensing missions there are tight interrelations between different requirements such as orbital altitude, revisit time, mission cycle life and spatial resolution. Also, all of these requirements can affect the whole design characteristics. During the last years application of the CE in the space missions has demonstrated a great advantage to reach the optimum design base lines considering both the performance and the cost of the project. A well-known example of CE application is ESA (European Space Agency) CDF (Concurrent Design Facility). It is clear that for the university-class microsatellite projects having or developing such a facility seems beyond the project capabilities. Nevertheless practicing CE at any scale can be beneficiary for the university-class microsatellite projects. In the second part of this thesis, the main focus is on developing a MDO framework applicable to the conceptual design phase of the remote sensing microsatellites. This approach enables the design team to evaluate the interaction between the different system design variables. The presented MDO framework contains not only the system level variables such as the satellite total mass and total power, but also the mission requirements like the spatial resolution and the revisit time. The microsatellite sizing process is divided into the three major design disciplines; a) orbit design, b) payload sizing and c) bus sizing. First, different mission parameters for a practical range of sun-synchronous orbits (SS-Os) are calculated. Then, according to the orbital parameters and a reference remote sensing instrument, mass and power of the payload are calculated. Satellite bus sizing is done based on mass and power calculation of the different subsystems using design estimation relationships. In the satellite bus sizing, the power subsystem design is realized by considering more detailed design variables including a mission scenario and different types of solar cells and batteries. The mission scenario is selected in order to obtain a coverage belt on the earth surface parallel to the earth equatorial after each revisit time. In order to evaluate the interrelations between the different variables inside the design space all the mentioned design disciplines are combined in a unified code. The integrated satellite system sizing tool developed in this section is considered as an application of the CE to the conceptual design of the remote sensing microsatellite projects. Finally, in order to apply the MDO methodology to the design problem, a basic MDO framework is adjusted to the developed satellite system design tool. Design optimization is done by means of a GA single objective algorithm with the objective function as minimizing the microsatellite total mass. According to the results of MDO application, there exist different optimum design points all with the minimum satellite total mass but with different mission variables. This output demonstrates the successful applicability of MDO approach for system engineering trade-off studies at the conceptual design phase of the design in such projects. The main conclusion of this thesis is that the classical design approach for the satellite design which usually starts with the mission and payload definition is not necessarily the best approach for all of the satellite projects. The university-class microsatellite is an example for such projects. Due to this fact an integrated satellite sizing tool including different design disciplines focusing on the structural subsystem and considering unknown payload is developed. According to the results the satellite total mass and available mass for the unknown payload are conflictive objectives. In order to find the Pareto-optimal a multiobjective GA optimization is conducted. Based on the optimization results it is concluded that selecting the satellite total mass in the range of 40-60 kg can be considered as an optimum approach for a university-class microsatellite project with unknown payload(s). Also, the CE methodology is applied to the remote sensing microsatellites conceptual design process. The results of CE application provide a clear understanding of the interaction between satellite system design requirements such as satellite total mass and power and the satellite mission variables such as revisit time and spatial resolution. The MDO application is done with the total mass minimization of a remote sensing satellite. The results from the MDO application clarify the unclear relationship between different system and mission design variables as well as the optimum design base lines according to the selected objective during the initial design phases.

Tiempo de desafíos, tiempo de reinvenciones: impacto y respuesta de un proveedor de servicios ante un proceso de concentración de proveedores

Este trabajo fin de Máster consiste en la realización de un modelo de respuesta ante procesos de concentración de proveedores, que permita a las empresas proveedoras de servicios profesionales adaptarse a las necesidades crecientes o decrecientes que puedan plantearse en los clientes, además de identificar las diferentes problemáticas que puedan aparecer, de cara a realizar una gestión adecuada de las mismas, garantizando la sostenibilidad económica del negocio. Este modelo de respuesta, estará formado por una serie de mecanismos, que mediante su activación posibilitarán que las empresas de servicios se encuentren preparadas y con garantías en las dos vertientes posibles que se derivan de un proceso de concentración, la más positiva, en la que el desarrollo de actividad requiera nuevas habilidades o nuevos dimensionamientos y la vertiente negativa, donde el nivel de actividad disminuirá. ---ABSTRACT---This Master final work is based on the creation of a response model for the concentration processes carried out by professional services clients, enabling companies that provides this kind of services the capabilities to be adapted for the increasing or decreasing needs that may arise, and identifying the problems that can appears, in order to make a proper management of them and ensuring the economic sustainability of the business. This pattern of response will consist on several mechanisms, which through its activation will enable the capabilities for professional services companies to be prepared and guaranteed the two possible angles derived from a concentration process, the more positive, where activity requires the development of new skills or new sizing and the negative one, where the level of activity decrease or disappears.

Discussion: Comparative study of breakwater crown wall - calculation methods

This paper presents an extensive and useful comparison of existing formulas to estimate wave forces on crown walls. The paper also provides valuable insights into crown wall behaviour, suggesting the use of formulas for prior sizing and recommending, in any case, tests on a physical model in order to confirm the final design. The authors helpfully advise to use more than one method to obtain results closer to reality, always taking into account the test conditions under which each formula was developed