Using non-homogeneous Poisson models with multiple change-points to estimate the number of ozone exceedances in Mexico City

In this paper, we consider some non-homogeneous Poisson models to estimate the probability that an air quality standard is exceeded a given number of times in a time interval of interest. We assume that the number of exceedances occurs according to a non-homogeneous Poisson process (NHPP). This Poisson process has rate function lambda(t), t >= 0, which depends on some parameters that must be estimated. We take into account two cases of rate functions: the Weibull and the Goel-Okumoto. We consider models with and without change-points. When the presence of change-points is assumed, we may have the presence of either one, two or three change-points, depending of the data set. The parameters of the rate functions are estimated using a Gibbs sampling algorithm. Results are applied to ozone data provided by the Mexico City monitoring network. In a first instance, we assume that there are no change-points present. Depending on the adjustment of the model, we assume the presence of either one, two or three change-points. Copyright (C) 2009 John Wiley & Sons, Ltd.

Random regression analyses using B-splines functions to model growth from birth to adult age in Canchim cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The two-loop massless (lambda/4!)phi(4) model in nontranslational invariant domain

We study the (lambda/4!)phi(4) massless scalar field theory in a four-dimensional Euclidean space, where all but one of the coordinates are unbounded. We are considering Dirichlet boundary conditions in two hyperplanes, breaking the translation invariance of the system. We show how to implement the perturbative renormalization up to two-loop level of the theory. First, analyzing the full two and four-point functions at the one-loop level, we show that the bulk counterterms are sufficient to render the theory finite. Meanwhile, at the two-loop level, we must also introduce surface counterterms in the bare Lagrangian in order to make finite the full two and also four-point Schwinger functions. (c) 2006 American Institute of Physics.

Sodium and chloride requirements of young broiler chickens fed corn-soybean diets (one to twenty-one days of age)

Sodium (Na+) and chloride (Cl-) nutritional requirements, dietary electrolyte balance (DEB), and their effects on acid-base balance, litter moisture, and tibial dyschondroplasia (TD) incidence for young broiler chickens were evaluated in two trials. One-day-old Cobb broilers were distributed in a completely randomized design with six treatments, five replicates, and 50 birds per experimental unit. Treatments used in both experiments were a basal diet with 0.10% Na+ (Experiment 1) or Cl- (Experiment 2) supplemented to result in diets with Na+ or Cl- levels of 0.10, 0.15, 0.20, 0.25 ,0.30, or 0.35%, respectively. In Experiment 1, results indicated an optimum Na+ requirement of 0.26%. Sodium levels caused a linear increase in arterial blood gas parameters, indicating an alkalogenic effect of Na+. The hypertrophic area of growth plate in the proximal tibiotarsi decreased with Na+ levels. The TD incidence decreased with increases in dietary Na+. Litter moisture increased linearly with sodium levels. In Experiment 2, the Cl- requirement was estimated as 0.25%. Chloride levels caused a quadratic effect (P ≤ 0.01) on blood gas parameters, with an estimated equilibrium [blood base excess (BE) = 0] at 0.30% of dietary CT-. No Cl- treatment effects (P ≥ 0.05) were observed on litter moisture or TD incidence. The best DEB for maximum performance was 298 to 315 mEq/kg in Experiment 1 and 246 to 264 mEq/kg in Experiment 2. We concluded that the Na+ and Cl- requirements for optimum performance of young broiler chickens were 0.28 and 0.25%, respectively.

A comparison of the film thickness of two adhesive luting agents and the effect of thermocycling on their microTBs to feldspathic ceramic.

The aim of the present study was to evaluate the effect of thermocycling (TC) on the microtensile bond strength (microTBS) of two luting agents to feldspathic ceramic and to measure their film thickness (FT). For the microTBS test, sixteen blocks (6.4 x 6.4 x 4.8 mm) were fabricated using a feldspathic ceramic, etched with 10% hydrofluoric acid, rinsed and treated with the silane agent. The ceramic blocks were divided into two groups (n= 8): Gr1: dual-cured resin cement and Gr2: flowable resin. The luting agents were applied on the treated surfaces. Microsticks (1 +/-0. 1mm2) were prepared and stored under two conditions: dry, specimens immediately submitted to the microTBS test, and TC (6,000 cycles; 5 degrees C-55 degrees C). The microTBS was evaluated using a universal testing machine (1 mm/min). The microTBS data (MPa) were submitted to two-way ANOVA and Tukey' test (5%). For the FT test (ISO 4049), 0.05 ml of each luting agent (n=8) was pressed between two Mylar-covered glass plates (150 N) for 180 seconds and light polymerized. FT was measured using a digital paquimeter (Model 727-2001). The data (mm) were submitted to one-way ANOVA. The luting cement did not influence the microTBS results (p= 0.4467). Higher microtensile bond values were found after TC (20.5 +/- 8.6 MPa) compared to the dry condition (13.9 +/- 4. 7MPa), for both luting agents. The luting agents presented similar film thicknesses: Gr1- 0.052 +/- 0.016 mm; Gr2-0.041 +/- 0.003 mm. The luting agents presented similar film thickness and microTBS values, in dry and TC conditions and TC increased the bond strength regardless of the luting agent.

Technique to combine images produced by different propagation modes of guided waves for damage detection and contrast improvement in plate-like structures

This paper describes an image compounding technique based on the use of different apodization functions, the evaluation of the signals phases and information from the interaction of different propagation modes of Lamb waves with defects for enhanced damage detection, resolution and contrast. A 16 elements linear array is attached to a 1 mm thickness isotropic aluminum plate with artificial defects. The array can excite the fundamental A0 and S0 modes at the frequencies of 100 kHz and 360 kHz, respectively. For each mode two synthetic aperture (SA) images with uniform and Blackman apodization and one image of Coherence Factor Map (CFM) are obtained. The specific interaction between each propagation mode and the defects and the characteristics of acoustic radiation patterns due to different apodization functions result in images with different resolution and contrast. From the phase information one of the SA images is selected at each pixel to compound the final image. The SA images are multiplied by the CFM image to improve contrast and for the dispersive A0 mode it is used a technique for dispersion compensation. There is a contrast improvement of 47.5 dB, reducing the dead zone and improving resolution and damage detection. © 2012 IEEE.

Assignment of Putative Functions to Membrane "Hypothetical Proteins" from the Trypanosoma cruzi Genome

Protozoan parasites cause thousands of deaths each year in developing countries. The genome projects of these parasites opened a new era in the identification of therapeutic targets. However, the putative function could be predicted for fewer than half of the protein-coding genes. In this work, all Trypanosoma cruzi proteins containing predicted transmembrane spans were processed through an automated computational routine and further analyzed in order to assign the most probable function. The analysis consisted of dissecting the whole predicted protein in different regions. More than 5,000 sequences were processed, and the predicted biological functions were grouped into 19 categories according to the hits obtained after analysis. One focus of interest, due to the scarce information available on trypanosomatids, is the proteins involved in signal-transduction processes. In the present work, we identified 54 proteins belonging to this group, which were individually analyzed. The results show that by means of a simple pipeline it was possible to attribute probable functions to sequences annotated as coding for "hypothetical proteins.'' Also, we successfully identified the majority of candidates participating in the signal-transduction pathways in T. cruzi.

Implantation of the biodegradable polymer biolimus-eluting stent in patients with high SYNTAX score is associated with decreased cardiac mortality compared to a permanent polymer sirolimus-eluting stent: two year follow-up results from the "all-comers" LEADERS trial

Background: The SYNTAX score (SXscore) has been shown to be an effective predictor of clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Methods and results: The SXscore was prospectively collected in 1,397 of the 1,707 patients enrolled in the “all-comers” LEADERS trial (patients post-surgical revascularisation were excluded). Post hoc analysis was performed by stratifying clinical outcomes at two-year follow-up, according to one of three SXscore tertiles: SXlow ≤8 (n=464), 816 (n=461). At two-year follow-up the rate of major adverse cardiovascular events was 18.4%, 12.0% and 9.4% in the SXhigh, SXmid, and SXlow tertile, respectively (HR 1.45; CI 1.21-1.74; p<0.01). There was a significantly higher rate of cardiac death in patients in the highest SXscore tertile (7% SXhigh versus 2.4% SXmid versus 1.8% SXlow; HR 2.22; CI 1.5-3.27; p<0.001). Within the SXhigh tertile the rate of cardiac death was significantly lower in patients treated with the biolimus-eluting stent compared with the sirolimus-eluting stent (4.7% versus 9.6%, HR 0.48; CI 0.23-0.99; p=0.046). Conclusions: The SXscore when applied to an “all-comers” patient population allows for prospective risk stratification of patients undergoing PCI up to two years follow-up. In addition, the SXscore appears to separate the performance of devices in high risk patient groups.

Effect of tin-chloride pretreatment on bond strength of two adhesive systems to dentin

OBJECTIVES: To determine the effect on resin composite-to-dentin bond strength of incorporation of an acidic tin-chloride pretreatment in two adhesive systems. MATERIALS AND METHODS: Human molars were ground to expose mid-coronal dentin. For microtensile bond strength (μTBS) testing, dentin was treated with Optibond FL or Clearfil SE according to one of six protocols (n = 22/group). Group 1: Phosphoric acid etching, Optibond FL Prime, Optibond FL Adhesive (manufacturer's instructions; control); Group 2: Tin-chloride pretreatment, Optibond FL Prime, Optibond FL Adhesive; Group 3: Phosphoric acid etching, tin-chloride pretreatment, Optibond FL Prime, Optibond FL Adhesive; Group 4: Clearfil SE Primer, Clearfil SE Bond (manufacturer's instructions; control); Group 5: Phosphoric acid etching, Clearfil SE Primer, Clearfil SE Bond; and Group 6: Tin-chloride pretreatment, Clearfil SE Primer, Clearfil SE Bond. The molars were then built up with resin composite (Clearfil Majesty Esthetic). After storage (1 week, 100  % humidity, 37 °C) the μTBS was measured and failure mode was determined. Additionally, pretreated dentin surfaces were evaluated using SEM and EDX. The μTBS results were analyzed statistically by a Welch Two Sample t-test and a Kruskal-Wallis test followed by exact Wilcoxon rank sum tests with Bonferroni-Holm adjustment for multiple testing (α = 0.05). RESULTS: When Optibond FL was used, partial or total replacement of phosphoric acid with tin-chloride decreased μTBS significantly. In contrast, when Clearfil SE was used, inclusion of a tin-chloride pretreatment in the adhesive procedure increased μTBS significantly. CONCLUSIONS: Tin-chloride pretreatment had a beneficial influence on the bond promoting capacity of the MDP-containing adhesive system Clearfil SE.

High-frequency signal generation using 1550 nm VCSEL subject to two-frequency optical injection

We experimentally investigate high-frequency microwave signal generation using a 1550 nm single-mode VCSEL subject to two-frequency optical injection. We first consider a situation in which the injected signals come from two similar VCSELs. The polarization of the injected light is parallel to that of the injected VCSEL. We obtain that the VCSEL can be locked to one of the injected signals, but the observed microwave signal is originated by beating at the photodetector. In a second situation we consider injected signals that come from two external cavity tunable lasers with a significant increase of the injected power with respect to the VCSEL-by-VCSEL injection case. The polarization of the injected light is orthogonal to that of the free-running slave VCSEL. We show that in this case it is possible to generate a microwave signal inside the VCSEL cavity. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Applications of Formal Languages to Management of Manned and Unmanned Aircraft

En el futuro, la gestión del tráfico aéreo (ATM, del inglés air traffic management) requerirá un cambio de paradigma, de la gestión principalmente táctica de hoy, a las denominadas operaciones basadas en trayectoria. Un incremento en el nivel de automatización liberará al personal de ATM —controladores, tripulación, etc.— de muchas de las tareas que realizan hoy. Las personas seguirán siendo el elemento central en la gestión del tráfico aéreo del futuro, pero lo serán mediante la gestión y toma de decisiones. Se espera que estas dos mejoras traigan un incremento en la eficiencia de la gestión del tráfico aéreo que permita hacer frente al incremento previsto en la demanda de transporte aéreo. Para aplicar el concepto de operaciones basadas en trayectoria, el usuario del espacio aéreo (la aerolínea, piloto, u operador) y el proveedor del servicio de navegación aérea deben negociar las trayectorias mediante un proceso de toma de decisiones colaborativo. En esta negociación, es necesaria una forma adecuada de compartir dichas trayectorias. Compartir la trayectoria completa requeriría un gran ancho de banda, y la trayectoria compartida podría invalidarse si cambiase la predicción meteorológica. En su lugar, podría compartirse una descripción de la trayectoria independiente de las condiciones meteorológicas, de manera que la trayectoria real se pudiese calcular a partir de dicha descripción. Esta descripción de la trayectoria debería ser fácil de procesar usando un programa de ordenador —ya que parte del proceso de toma de decisiones estará automatizado—, pero también fácil de entender para un operador humano —que será el que supervise el proceso y tome las decisiones oportunas—. Esta tesis presenta una serie de lenguajes formales que pueden usarse para este propósito. Estos lenguajes proporcionan los medios para describir trayectorias de aviones durante todas las fases de vuelo, desde la maniobra de push-back (remolcado hasta la calle de rodaje), hasta la llegada a la terminal del aeropuerto de destino. También permiten describir trayectorias tanto de aeronaves tripuladas como no tripuladas, incluyendo aviones de ala fija y cuadricópteros. Algunos de estos lenguajes están estrechamente relacionados entre sí, y organizados en una jerarquía. Uno de los lenguajes fundamentales de esta jerarquía, llamado aircraft intent description language (AIDL), ya había sido desarrollado con anterioridad a esta tesis. Este lenguaje fue derivado de las ecuaciones del movimiento de los aviones de ala fija, y puede utilizarse para describir sin ambigüedad trayectorias de este tipo de aeronaves. Una variante de este lenguaje, denominada quadrotor AIDL (QR-AIDL), ha sido desarrollada en esta tesis para permitir describir trayectorias de cuadricópteros con el mismo nivel de detalle. Seguidamente, otro lenguaje, denominado intent composite description language (ICDL), se apoya en los dos lenguajes anteriores, ofreciendo más flexibilidad para describir algunas partes de la trayectoria y dejar otras sin especificar. El ICDL se usa para proporcionar descripciones genéricas de maniobras comunes, que después se particularizan y combinan para formar descripciones complejas de un vuelo. Otro lenguaje puede construirse a partir del ICDL, denominado flight intent description language (FIDL). El FIDL especifica requisitos de alto nivel sobre las trayectorias —incluyendo restricciones y objetivos—, pero puede utilizar características del ICDL para proporcionar niveles de detalle arbitrarios en las distintas partes de un vuelo. Tanto el ICDL como el FIDL han sido desarrollados en colaboración con Boeing Research & Technology Europe (BR&TE). También se ha desarrollado un lenguaje para definir misiones en las que interactúan varias aeronaves, el mission intent description language (MIDL). Este lenguaje se basa en el FIDL y mantiene todo su poder expresivo, a la vez que proporciona nuevas semánticas para describir tareas, restricciones y objetivos relacionados con la misión. En ATM, los movimientos de un avión en la superficie de aeropuerto también tienen que ser monitorizados y gestionados. Otro lenguaje formal ha sido diseñado con este propósito, llamado surface movement description language (SMDL). Este lenguaje no pertenece a la jerarquía de lenguajes descrita en el párrafo anterior, y se basa en las clearances (autorizaciones del controlador) utilizadas durante las operaciones en superficie de aeropuerto. También proporciona medios para expresar incertidumbre y posibilidad de cambios en las distintas partes de la trayectoria. Finalmente, esta tesis explora las aplicaciones de estos lenguajes a la predicción de trayectorias y a la planificación de misiones. El concepto de trajectory language processing engine (TLPE) se usa en ambas aplicaciones. Un TLPE es una función de ATM cuya principal entrada y salida se expresan en cualquiera de los lenguajes incluidos en la jerarquía descrita en esta tesis. El proceso de predicción de trayectorias puede definirse como una combinación de TLPEs, cada uno de los cuales realiza una pequeña sub-tarea. Se le ha dado especial importancia a uno de estos TLPEs, que se encarga de generar el perfil horizontal, vertical y de configuración de la trayectoria. En particular, esta tesis presenta un método novedoso para la generación del perfil vertical. El proceso de planificar una misión también se puede ver como un TLPE donde la entrada se expresa en MIDL y la salida consiste en cierto número de trayectorias —una por cada aeronave disponible— descritas utilizando FIDL. Se ha formulado este problema utilizando programación entera mixta. Además, dado que encontrar caminos óptimos entre distintos puntos es un problema fundamental en la planificación de misiones, también se propone un algoritmo de búsqueda de caminos. Este algoritmo permite calcular rápidamente caminos cuasi-óptimos que esquivan todos los obstáculos en un entorno urbano. Los diferentes lenguajes formales definidos en esta tesis pueden utilizarse como una especificación estándar para la difusión de información entre distintos actores de la gestión del tráfico aéreo. En conjunto, estos lenguajes permiten describir trayectorias con el nivel de detalle necesario en cada aplicación, y se pueden utilizar para aumentar el nivel de automatización explotando esta información utilizando sistemas de soporte a la toma de decisiones. La aplicación de estos lenguajes a algunas funciones básicas de estos sistemas, como la predicción de trayectorias, han sido analizadas. ABSTRACT Future air traffic management (ATM) will require a paradigm shift from today’s mainly tactical ATM to trajectory-based operations (TBOs). An increase in the level of automation will also relieve humans —air traffic control officers (ATCOs), flight crew, etc.— from many of the tasks they perform today. Humans will still be central in this future ATM, as decision-makers and managers. These two improvements (TBOs and increased automation) are expected to provide the increase in ATM performance that will allow coping with the expected increase in air transport demand. Under TBOs, trajectories are negotiated between the airspace user (an airline, pilot, or operator) and the air navigation service provider (ANSP) using a collaborative decision making (CDM) process. A suitable method for sharing aircraft trajectories is necessary for this negotiation. Sharing a whole trajectory would require a high amount of bandwidth, and the shared trajectory might become invalid if the weather forecast changed. Instead, a description of the trajectory, decoupled from the weather conditions, could be shared, so that the actual trajectory could be computed from this trajectory description. This trajectory description should be easy to process using a computing program —as some of the CDM processes will be automated— but also easy to understand for a human operator —who will be supervising the process and making decisions. This thesis presents a series of formal languages that can be used for this purpose. These languages provide the means to describe aircraft trajectories during all phases of flight, from push back to arrival at the gate. They can also describe trajectories of both manned and unmanned aircraft, including fixedwing and some rotary-wing aircraft (quadrotors). Some of these languages are tightly interrelated and organized in a language hierarchy. One of the key languages in this hierarchy, the aircraft intent description language (AIDL), had already been developed prior to this thesis. This language was derived from the equations of motion of fixed-wing aircraft, and can provide an unambiguous description of fixed-wing aircraft trajectories. A variant of this language, the quadrotor AIDL (QR-AIDL), is developed in this thesis to allow describing a quadrotor aircraft trajectory with the same level of detail. Then, the intent composite description language (ICDL) is built on top of these two languages, providing more flexibility to describe some parts of the trajectory while leaving others unspecified. The ICDL is used to provide generic descriptions of common aircraft manoeuvres, which can be particularized and combined to form complex descriptions of flight. Another language is built on top of the ICDL, the flight intent description language (FIDL). The FIDL specifies high-level requirements on trajectories —including constraints and objectives—, but can use features of the ICDL to provide arbitrary levels of detail in different parts of the flight. The ICDL and FIDL have been developed in collaboration with Boeing Research & Technology Europe (BR&TE). Also, the mission intent description language (MIDL) has been developed to allow describing missions involving multiple aircraft. This language is based on the FIDL and keeps all its expressive power, while it also provides new semantics for describing mission tasks, mission objectives, and constraints involving several aircraft. In ATM, the movement of aircraft while on the airport surface also has to be monitored and managed. Another formal language has been designed for this purpose, denoted surface movement description language (SMDL). This language does not belong to the language hierarchy described above, and it is based on the clearances used in airport surface operations. Means to express uncertainty and mutability of different parts of the trajectory are also provided. Finally, the applications of these languages to trajectory prediction and mission planning are explored in this thesis. The concept of trajectory language processing engine (TLPE) is used in these two applications. A TLPE is an ATM function whose main input and output are expressed in any of the languages in the hierarchy described in this thesis. A modular trajectory predictor is defined as a combination of multiple TLPEs, each of them performing a small subtask. Special attention is given to the TLPE that builds the horizontal, vertical, and configuration profiles of the trajectory. In particular, a novel method for the generation of the vertical profile is presented. The process of planning a mission can also be seen as a TLPE, where the main input is expressed in the MIDL and the output consists of a number of trajectory descriptions —one for each aircraft available in the mission— expressed in the FIDL. A mixed integer linear programming (MILP) formulation for the problem of assigning mission tasks to the available aircraft is provided. In addition, since finding optimal paths between locations is a key problem to mission planning, a novel path finding algorithm is presented. This algorithm can compute near-shortest paths avoiding all obstacles in an urban environment in very short times. The several formal languages described in this thesis can serve as a standard specification to share trajectory information among different actors in ATM. In combination, these languages can describe trajectories with the necessary level of detail for any application, and can be used to increase automation by exploiting this information using decision support tools (DSTs). Their applications to some basic functions of DSTs, such as trajectory prediction, have been analized.

Development of a sensorimotor algorithm able to deal with unforeseen pushes and its implementation based on VHDL

Development of a Sensorimotor Algorithm Able to Deal with Unforeseen Pushes and Its Implementation Based on VHDL is the title of my thesis which concludes my Bachelor Degree in the Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación of the Universidad Politécnica de Madrid. It encloses the overall work I did in the Neurorobotics Research Laboratory from the Beuth Hochschule für Technik Berlin during my ERASMUS year in 2015. This thesis is focused on the field of robotics, specifically an electronic circuit called Cognitive Sensorimotor Loop (CSL) and its control algorithm based on VHDL hardware description language. The reason that makes the CSL special resides in its ability to operate a motor both as a sensor and an actuator. This way, it is possible to achieve a balanced position in any of the robot joints (e.g. the robot manages to stand) without needing any conventional sensor. In other words, the back electromotive force (EMF) induced by the motor coils is measured and the control algorithm responds depending on its magnitude. The CSL circuit contains mainly an analog-to-digital converter (ADC) and a driver. The ADC consists on a delta-sigma modulation which generates a series of bits with a certain percentage of 1's and 0's, proportional to the back EMF. The control algorithm, running in a FPGA, processes the bit frame and outputs a signal for the driver. This driver, which has an H bridge topology, gives the motor the ability to rotate in both directions while it's supplied with the power needed. The objective of this thesis is to document the experiments and overall work done on push ignoring contractive sensorimotor algorithms, meaning sensorimotor algorithms that ignore large magnitude forces (compared to gravity) applied in a short time interval on a pendulum system. This main objective is divided in two sub-objectives: (1) developing a system based on parameterized thresholds and (2) developing a system based on a push bypassing filter. System (1) contains a module that outputs a signal which blocks the main Sensorimotor algorithm when a push is detected. This module has several different parameters as inputs e.g. the back EMF increment to consider a force as a push or the time interval between samples. System (2) consists on a low-pass Infinite Impulse Response digital filter. It cuts any frequency considered faster than a certain push oscillation. This filter required an intensive study on how to implement some functions and data types (fixed or floating point data) not supported by standard VHDL packages. Once this was achieved, the next challenge was to simplify the solution as much as possible, without using non-official user made packages. Both systems behaved with a series of interesting advantages and disadvantages for the elaboration of the document. Stability, reaction time, simplicity or computational load are one of the many factors to be studied in the designed systems. RESUMEN. Development of a Sensorimotor Algorithm Able to Deal with Unforeseen Pushes and Its Implementation Based on VHDL es un Proyecto de Fin de Grado (PFG) que concluye mis estudios en la Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación de la Universidad Politécnica de Madrid. En él se documenta el trabajo de investigación que realicé en el Neurorobotics Research Laboratory de la Beuth Hochschule für Technik Berlin durante el año 2015 mediante el programa de intercambio ERASMUS. Este PFG se centra en el campo de la robótica y en concreto en un circuito electrónico llamado Cognitive Sensorimotor Loop (CSL) y su algoritmo de control basado en lenguaje de modelado hardware VHDL. La particularidad del CSL reside en que se consigue que un motor haga las veces tanto de sensor como de actuador. De esta manera es posible que las articulaciones de un robot alcancen una posición de equilibrio (p.ej. el robot se coloca erguido) sin la necesidad de sensores en el sentido estricto de la palabra. Es decir, se mide la propia fuerza electromotriz (FEM) inducida sobre el motor y el algoritmo responde de acuerdo a su magnitud. El circuito CSL se compone de un convertidor analógico-digital (ADC) y un driver. El ADC consiste en un modulador sigma-delta, que genera una serie de bits con un porcentaje de 1's y 0's determinado, en proporción a la magnitud de la FEM inducida. El algoritmo de control, que se ejecuta en una FPGA, procesa esta cadena de bits y genera una señal para el driver. El driver, que posee una topología en puente H, provee al motor de la potencia necesaria y le otorga la capacidad de rotar en cualquiera de las dos direcciones. El objetivo de este PFG es documentar los experimentos y en general el trabajo realizado en algoritmos Sensorimotor que puedan ignorar fuerzas de gran magnitud (en comparación con la gravedad) y aplicadas en una corta ventana de tiempo. En otras palabras, ignorar empujones conservando el comportamiento original frente a la gravedad. Para ello se han desarrollado dos sistemas: uno basado en umbrales parametrizados (1) y otro basado en un filtro de corte ajustable (2). El sistema (1) contiene un módulo que, en el caso de detectar un empujón, genera una señal que bloquea el algoritmo Sensorimotor. Este módulo recibe diferentes parámetros como el incremento necesario de la FEM para que se considere un empujón o la ventana de tiempo para que se considere la existencia de un empujón. El sistema (2) consiste en un filtro digital paso-bajo de respuesta infinita que corta cualquier variación que considere un empujón. Para crear este filtro se requirió un estudio sobre como implementar ciertas funciones y tipos de datos (coma fija o flotante) no soportados por las librerías básicas de VHDL. Tras esto, el objetivo fue simplificar al máximo la solución del problema, sin utilizar paquetes de librerías añadidos. En ambos sistemas aparecen una serie de ventajas e inconvenientes de interés para el documento. La estabilidad, el tiempo de reacción, la simplicidad o la carga computacional son algunas de las muchos factores a estudiar en los sistemas diseñados. Para concluir, también han sido documentadas algunas incorporaciones a los sistemas: una interfaz visual en VGA, un módulo que compensa el offset del ADC o la implementación de una batería de faders MIDI entre otras.

Somatic Cell Mutants Resistant to Retrovirus Replication: Intracellular Blocks during the Early Stages of Infection

To identify cellular functions involved in the early phase of the retroviral life cycle, somatic cell mutants were isolated after selection for resistance to infection. Rat2 fibroblasts were treated with chemical mutagens, and individual virus-resistant clones were recovered after selection for resistance to infection. Two clones were characterized in detail. Both mutant lines were resistant to infection by both ecotropic and amphotropic murine viruses, as well as by human immunodeficiency virus type 1 pseudotypes. One clone showed a strong block to reverse transcription of the retroviral RNA, including formation of the earliest DNA products. The second clone showed normal levels of viral DNA synthesis but did not allow formation of the circular DNAs normally found in the nucleus. Cell fractionation showed that the viral preintegration complex was present in a form that could not be extracted under conditions that readily extracted the complex from wild-type cells. The results suggest that the DNA was trapped in a nonproductive state and excluded from the nucleus of the infected cell. The properties of these two mutant lines suggest that host gene products play important roles both before and after reverse transcription.

A Geometrical Interpretation to Define Contradiction Degrees between Two Fuzzy Sets

For inference purposes in both classical and fuzzy logic, neither the information itself should be contradictory, nor should any of the items of available information contradict each other. In order to avoid these troubles in fuzzy logic, a study about contradiction was initiated by Trillas et al. in [5] and [6]. They introduced the concepts of both self-contradictory fuzzy set and contradiction between two fuzzy sets. Moreover, the need to study not only contradiction but also the degree of such contradiction is pointed out in [1] and [2], suggesting some measures for this purpose. Nevertheless, contradiction could have been measured in some other way. This paper focuses on the study of contradiction between two fuzzy sets dealing with the problem from a geometrical point of view that allow us to find out new ways to measure the contradiction degree. To do this, the two fuzzy sets are interpreted as a subset of the unit square, and the so called contradiction region is determined. Specially we tackle the case in which both sets represent a curve in [0,1]2. This new geometrical approach allows us to obtain different functions to measure contradiction throughout distances. Moreover, some properties of these contradiction measure functions are established and, in some particular case, the relations among these different functions are obtained.

Effects of two intervention strategies on the behavior of nurses and nurse students related to advance directives

Advance directives are one mechanism for preserving the rights of individuals to exercise some control over their health care when serious illness may prevent them from direct participation. Nurses, as the health care providers with the closest and most sustained contact with critically ill and dying patients, are positioned to assist patients to plan for future health care needs. Although a majority of nurses favor the concept of advance directives for their patients and for themselves, they have not played a significant role in facilitating advance health care planning with their patients nor implemented advance health care planning for themselves.^ Research has also shown that differing forms of education and counseling increase the completion rates for advance directives in selected populations, mostly the elderly and seriously ill. Not yet developed are effective educational strategies to assist nurses and nurse students to make optimal contributions in assisting their clients' plans for future health care decision-making. This study sought to determine whether specific learning strategies (a) increased the involvement of nurses and nurse students in facilitating advance care planning with patients and (b) increased the percentage of the nurses' and nurse students' own personal advance care planning activities.^ The study compared two learning interventions and two populations, nurses and nurse students. The participants were randomly assigned to one of the two learning interventions, L1 or L2. Participants in L1 received a lecture, discussion and exploration of the forces impacting on advance directive behavior. Participants in L2 received the same intervention components with the additional component of group practice completing advance directives.^ Analysis of the data by chi-square and logistic regression did not support the hypotheses that the practice component would make a difference in the participants' facilitation of advance care planning with patients or in their own personal advance care planning activities. There were significant differences in post-intervention behavior between the nurse and nurse student groups. The nurses in the study did significantly more facilitation of advance care planning with patients and completed significantly more advance care documents than the nurse students post-intervention. However, the nurse students held more post-intervention family discussions than did the nurses. ^