774 resultados para Test–retest repeatability


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The consumers are becoming more concerned about food quality, especially regarding how, when and where the foods are produced (Haglund et al., 1999; Kahl et al., 2004; Alföldi, et al., 2006). Therefore, during recent years there has been a growing interest in the methods for food quality assessment, especially in the picture-development methods as a complement to traditional chemical analysis of single compounds (Kahl et al., 2006). The biocrystallization as one of the picture-developing method is based on the crystallographic phenomenon that when crystallizing aqueous solutions of dihydrate CuCl2 with adding of organic solutions, originating, e.g., from crop samples, biocrystallograms are generated with reproducible crystal patterns (Kleber & Steinike-Hartung, 1959). Its output is a crystal pattern on glass plates from which different variables (numbers) can be calculated by using image analysis. However, there is a lack of a standardized evaluation method to quantify the morphological features of the biocrystallogram image. Therefore, the main sakes of this research are (1) to optimize an existing statistical model in order to describe all the effects that contribute to the experiment, (2) to investigate the effect of image parameters on the texture analysis of the biocrystallogram images, i.e., region of interest (ROI), color transformation and histogram matching on samples from the project 020E170/F financed by the Federal Ministry of Food, Agriculture and Consumer Protection(BMELV).The samples are wheat and carrots from controlled field and farm trials, (3) to consider the strongest effect of texture parameter with the visual evaluation criteria that have been developed by a group of researcher (University of Kassel, Germany; Louis Bolk Institute (LBI), Netherlands and Biodynamic Research Association Denmark (BRAD), Denmark) in order to clarify how the relation of the texture parameter and visual characteristics on an image is. The refined statistical model was accomplished by using a lme model with repeated measurements via crossed effects, programmed in R (version 2.1.0). The validity of the F and P values is checked against the SAS program. While getting from the ANOVA the same F values, the P values are bigger in R because of the more conservative approach. The refined model is calculating more significant P values. The optimization of the image analysis is dealing with the following parameters: ROI(Region of Interest which is the area around the geometrical center), color transformation (calculation of the 1 dimensional gray level value out of the three dimensional color information of the scanned picture, which is necessary for the texture analysis), histogram matching (normalization of the histogram of the picture to enhance the contrast and to minimize the errors from lighting conditions). The samples were wheat from DOC trial with 4 field replicates for the years 2003 and 2005, “market samples”(organic and conventional neighbors with the same variety) for 2004 and 2005, carrot where the samples were obtained from the University of Kassel (2 varieties, 2 nitrogen treatments) for the years 2004, 2005, 2006 and “market samples” of carrot for the years 2004 and 2005. The criterion for the optimization was repeatability of the differentiation of the samples over the different harvest(years). For different samples different ROIs were found, which reflect the different pictures. The best color transformation that shows efficiently differentiation is relied on gray scale, i.e., equal color transformation. The second dimension of the color transformation only appeared in some years for the effect of color wavelength(hue) for carrot treated with different nitrate fertilizer levels. The best histogram matching is the Gaussian distribution. The approach was to find a connection between the variables from textural image analysis with the different visual criteria. The relation between the texture parameters and visual evaluation criteria was limited to the carrot samples, especially, as it could be well differentiated by the texture analysis. It was possible to connect groups of variables of the texture analysis with groups of criteria from the visual evaluation. These selected variables were able to differentiate the samples but not able to classify the samples according to the treatment. Contrarily, in case of visual criteria which describe the picture as a whole there is a classification in 80% of the sample cases possible. Herewith, it clearly can find the limits of the single variable approach of the image analysis (texture analysis).

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Die Qualität ökologischer Produkte wird über den Prozess und nicht am Produkt selbst bestimmt. Die zunehmende Nachfrage nach ökologischen Produkten fordert Methoden, die den Prozess am Produkt zeigen (Authentizitätsprüfung). Eine Literaturstudie für die vorliegende Habilitationsschrift ergab, dass ganzheitliche Verfahren sich dazu besonders eignen. Zu solchen ganzheitlichen Verfahren gehört die Biokristallisation. Bei diesem Verfahren kristallisiert eine Mischung aus Probe und CuCl2 auf einer Glasplatte zu einem Bild, das sowohl visuell, als auch computergestützt ausgewertet werden kann. Es wurden zunächst alle Schritte im Labor dokumentiert und entsprechende Standardarbeitsanweisungen erstellt. Mit einem eigens entwickelten Computerprogramm werden die Bedingungen während der Probenaufbereitung und Kristallisation für jede Probe und jedes Bild erfasst. Mit einer Texturanalyse können auch die für diese Arbeiten erstellte große Menge an Bildern ausgewertet und die Ergebnisse statistisch bearbeitet werden. Damit ist es möglich das Verfahren und Methoden für Weizen- und Möhrenproben zu charakterisieren. Es wurden verschiedene Einflussgrößen untersucht. Das Verfahren ist besonders gegenüber Änderungen in der Probenvorbereitung (z.B. Vermahlung, Mischungsverhältnis) empfindlich. Es wurde sowohl die Methodenstreuung, als auch der Anteil einzelner Schritte an der Gesamtstreuung für Weizen-, Möhren- und Apfelproben ermittelt. Die Verdampfung und Kristallisation hat den größten Anteil an der Gesamtstreuung. Die Durchführung eines Laboreignungstests zeigte, dass die so dokumentierten und charakterisierten Methoden in anderen Laboratorien erfolgreich eingesetzt werden können. Das Verfahren wurde für die nominale Unterscheidung von Weizen-, Möhren- und Apfelproben aus unterschiedlichem Anbau und Verarbeitungsschritten eingesetzt. Weizen-, Möhren- und Apfelproben aus definiertem Anbau können signifikant unterschieden werden. Weizen-, Möhren- und Apfelproben vom Erzeuger (Markt) konnten im Paarvergleich (ökologisch, konventionell) teilweise signifikant getrennt werden. Das Verfahren ist auch für die Charakterisierung von verarbeiteten Proben einsetzbar. Es konnte der Einfluss von Saftherstellung, Erwärmung und Alterung signifikant gezeigt werden. Darüber hinaus lässt sich das Verfahren auf weitere Probenarten anwenden. Das Verfahren arbeitet ganzheitlich, d.h. es werden keine Einzelstoffe analytisch bestimmt, sondern als Ergebnis wird ein Bild erhalten. Die Textur- und Struktureigenschaften dieses Bildes können mit standardisierten Methoden ausgewertet werden.

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A closed-form solution formula for the kinematic control of manipulators with redundancy is derived, using the Lagrangian multiplier method. Differential relationship equivalent to the Resolved Motion Method has been also derived. The proposed method is proved to provide with the exact equilibrium state for the Resolved Motion Method. This exactness in the proposed method fixes the repeatability problem in the Resolved Motion Method, and establishes a fixed transformation from workspace to the joint space. Also the method, owing to the exactness, is demonstrated to give more accurate trajectories than the Resolved Motion Method. In addition, a new performance measure for redundancy control has been developed. This measure, if used with kinematic control methods, helps achieve dexterous movements including singularity avoidance. Compared to other measures such as the manipulability measure and the condition number, this measure tends to give superior performances in terms of preserving the repeatability property and providing with smoother joint velocity trajectories. Using the fixed transformation property, Taylor's Bounded Deviation Paths Algorithm has been extended to the redundant manipulators.

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Wednesday 23rd April 2014 Speaker(s): Willi Hasselbring Organiser: Leslie Carr Time: 23/04/2014 11:00-11:50 Location: B32/3077 File size: 669 Mb Abstract For good scientific practice, it is important that research results may be properly checked by reviewers and possibly repeated and extended by other researchers. This is of particular interest for "digital science" i.e. for in-silico experiments. In this talk, I'll discuss some issues of how software systems and services may contribute to good scientific practice. Particularly, I'll present our PubFlow approach to automate publication workflows for scientific data. The PubFlow workflow management system is based on established technology. We integrate institutional repository systems (based on EPrints) and world data centers (in marine science). PubFlow collects provenance data automatically via our monitoring framework Kieker. Provenance information describes the origins and the history of scientific data in its life cycle, and the process by which it arrived. Thus, provenance information is highly relevant to repeatability and trustworthiness of scientific results. In our evaluation in marine science, we collaborate with the GEOMAR Helmholtz Centre for Ocean Research Kiel.

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El propósito de este estudio es evaluar la sensibilidad, especificidad y valores predictivos del Cuestionario Anamnésico de Síntomas de Miembro Superior y Columna (CASMSC) desarrollado por la Unidad de Investigación de Ergonomía de Postura y Movimiento (EPM). Se realizó un estudio descriptivo de tipo correlacional, mediante el análisis de datos secundarios de una base de datos con registros de trabajadores de la industria de alimentos (n=401) en el año 2013, a quienes se les había aplicado el CASMSC, así como una evaluación clínica fisioterapéutica enfocada en los mismos segmentos corporales; esta última utilizada como prueba de oro. Para analizar si existían diferencias estadísticas por edad, antigüedad y género se aplicó el análisis de varianza de una vía. La sensibilidad, especificidad y valores predictivos del CASMSC se informan con sus respectivos intervalos de confianza (95%). La prevalencia de umbral positivo para sospecha de Desorden Músculo Esquelético (DME) tanto de miembro superior como de columna se encontró muy por encima de la media nacional para el sector. La sensibilidad del CASMSC para miembro superior estuvo en el rango de un 80% a 94,57% y para columna cervical y lumbar fue de 36,4% y 43,4%, respectivamente. Para la región dorsal fue casi del doble de las otras dos regiones (85,7%). El CASMSC es recomendable en su apartado para miembro superior dado a su alto nivel de sensibilidad.

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Los grandes aportes generados por las antiguas civilizaciones y los filósofos más destacados a lo largo del tiempo, permiten entender la procedencia de algunos términos de los que hoy en día se hace uso. Estas contribuciones comienzan a través de la concepción del término tiempo, desde la antigüedad hasta los tiempos modernos, las cuales conllevan a entender que el tiempo es aquel que define la durabilidad de las cosas. De acuerdo a esto, se propone un acercamiento sobre el origen del término perdurabilidad, el cual será la base de la presente investigación. Entender la procedencia del término y el uso que se le da a sí mismo, facilita la aplicación el ámbito empresarial; el cual, a partir de diferentes posturas de autores nacionales e internacionales y basados en los parámetros que ha establecido la Universidad del Rosario, se establece un marco teórico de apoyo para futuras investigaciones dedicadas a la perdurabilidad empresarial. Asimismo, se establecen o se plasman algunos principios o factores de éxito que ayudan a que una empresa logre traspasar fronteras en tiempo y en rentabilidad; es decir que no solo permanezca muchos años en el mercado, sino que además se mantenga en constante crecimiento y rentabilidad.

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RESUMEN INTRODUCCION Los desórdenes musculoesqueléticos constituyen uno de los más comunes y costosos problemas de salud en el trabajo en todo el mundo. La detección a tiempo de síntomas iniciales debe ser una prioridad de los sistemas de vigilancia epidemiológica. El objetivo de este trabajo de investigación fue determinar la prevalencia de los desórdenes musculoesqueléticos (DME) en la población de funcionarios del cuerpo de policía judicial de Bogotá en el año 2014. MATERIALES Y METODOS Estudio de corte transversal con una muestra de 300 trabajadores a los que se les aplico el cuestionario Nórdico de Síntomas musculoesqueléticos. RESULTADOS Se encuesto al 33,9% de los trabajadores pertenecientes al cuerpo técnico de Policía Judicial de la Fiscalía General de la Nación en la ciudad de Bogotá. Los trabajadores evaluados tienen una edad promedio de 41,9 años, con un predominio del género femenino (54%), encontrándose que la mayoría de los que respondieron al cuestionario 87,66% (n=263) habían presentado algún síntoma musculoesqueléticos en los últimos 12 meses. Un hallazgo significativo fue la afectación cervical en el 53% (n=159) de los que reportaron sintomatología musculo esquelética. CONCLUSIONES La población perteneciente a la Policía Técnica Judicial en la ciudad de Bogotá presenta una alta prevalencia (87,66%) de síntomas que afectan al sistema musculoesquelético, principalmente comprometiendo las regiones de columna cervical, parte baja de la espalda y parte alta de la espalda, con una mayor afectación a las personas de género femenino.

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Cortical auditory evoked potentials were recorded in cochlear implant recipients and in individuals with normal hearing using a speech stimulus. Responses were acquired over two test sessions to investigate between group differences and test repeatability. Results indicate significant differences in N1-P2 latency and amplitude measures between cochlear implant recipients and individuals with normal hearing.

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Fluorophos and colourimetric procedures for alkaline phosphatase (ALP) testing were compared using milk with raw milk additions, purified bovine ALP additions and heat treatments. Repeatability was between 0.9% and 10.1% for Fluorophos, 3.5% and 46.1% for the Aschaffenburg and Mullen (A&M) procedure and 4.4% and 8.8% for the Scharer rapid test. Linearity (R-2) using raw milk addition was 0.96 between Fluorophos and the Scharer procedure. Between the Fluorophos and the A&M procedures, R-2 values were 0.98, 0.99 and 0.98 for raw milk additions, bovine ALP additions and heat treatments respectively. Fluorophos showed greater sensitivity and was both faster and simpler to perform.

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In this study, we report on the development and psychometric evaluation of the Risk-Taking (RT) and Self-Harm (SH) Inventory for Adolescents (RTSHIA), a self-report measure designed to assess adolescent RT and SH in community and clinical settings. 651 young people from secondary schools in England ranging in age from 11.6 years to 18.7 years and 71 young people referred to mental health services for SH behavior in London between the ages of 11.9 years and 17.5 years completed the RTSHIA along with standardized measures of adolescent psychopathology. Two factors emerged from the principal axis factoring, and RT and SH were further validated by a confirmatory factor analysis as related, but different, constructs, rather than elements of a single continuum. Inter-item and test–retest reliabilities were high for both components (Cronbach's α = .85, rtt = .90; Cronbach's α .93, rtt = .87), and considerable evidence emerged in support of the measure's convergent, concurrent, and divergent validity. The findings are discussed with regard to potential usefulness of the RTSHIA for research and clinical purposes with adolescents.

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The meltabilities of 14 process cheese samples were determined at 2 and 4 weeks after manufacture using sensory analysis, a computer vision method, and the Olson and Price test. Sensory analysis meltability correlated with both computer vision meltability (R-2 = 0.71, P < 0.001) and Olson and Price meltability (R-2 = 0.69, P < 0.001). There was a marked lack of correlation between the computer vision method and the Olson and Price test. This study showed that the Olson and Price test gave greater repeatability than the computer vision method. Results showed process cheese meltability decreased with increasing inorganic salt content and with lower moisture/fat ratios. There was very little evidence in this study to show that process cheese meltability changed between 2 and 4 weeks after manufacture..

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Recursive Learning Control (RLC) has the potential to significantly reduce the tracking error in many repetitive trajectory applications. This paper presents an application of RLC to a soil testing load frame where non-adaptive techniques struggle with the highly nonlinear nature of soil. The main purpose of the controller is to apply a sinusoidal force reference trajectory on a soil sample with a high degree of accuracy and repeatability. The controller uses a feedforward control structure, recursive least squares adaptation algorithm and RLC to compensate for periodic errors. Tracking error is reduced and stability is maintained across various soil sample responses.

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This report presents the canonical Hamiltonian formulation of relative satellite motion. The unperturbed Hamiltonian model is shown to be equivalent to the well known Hill-Clohessy-Wilshire (HCW) linear formulation. The in°uence of perturbations of the nonlinear Gravitational potential and the oblateness of the Earth; J2 perturbations are also modelled within the Hamiltonian formulation. The modelling incorporates eccentricity of the reference orbit. The corresponding Hamiltonian vector ¯elds are computed and implemented in Simulink. A numerical method is presented aimed at locating periodic or quasi-periodic relative satellite motion. The numerical method outlined in this paper is applied to the Hamiltonian system. Although the orbits considered here are weakly unstable at best, in the case of eccentricity only, the method ¯nds exact periodic orbits. When other perturbations such as nonlinear gravitational terms are added, drift is signicantly reduced and in the case of the J2 perturbation with and without the nonlinear gravitational potential term, bounded quasi-periodic solutions are found. Advantages of using Newton's method to search for periodic or quasi-periodic relative satellite motion include simplicity of implementation, repeatability of solutions due to its non-random nature, and fast convergence. Given that the use of bounded or drifting trajectories as control references carries practical di±culties over long-term missions, Principal Component Analysis (PCA) is applied to the quasi-periodic or slowly drifting trajectories to help provide a closed reference trajectory for the implementation of closed loop control. In order to evaluate the e®ect of the quality of the model used to generate the periodic reference trajectory, a study involving closed loop control of a simulated master/follower formation was performed. 2 The results of the closed loop control study indicate that the quality of the model employed for generating the reference trajectory used for control purposes has an important in°uence on the resulting amount of fuel required to track the reference trajectory. The model used to generate LQR controller gains also has an e®ect on the e±ciency of the controller.

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Evolutionary processes play a central role in the development, progression and response to treatment of cancers. The current challenge facing researchers is to harness evolutionary theory to further our understanding of the clinical progression of cancers. Central to this endeavour will be the development of experimental systems and approaches by which theories of cancer evolution can be effectively tested. We argue here that the experimental evolution approach – whereby evolution is observed in real time and which has typically employed microorganisms – can be usefully applied to cancer. This approach allows us to disentangle the ecological causes of natural selection, identify the genetic basis of evolutionary changes and determine their repeatability. Cell cultures used in cancer research share many of the desirable traits that make microorganisms ideal for studying evolution. As such, experimental cancer evolution is feasible and likely to give great insight into the selective pressures driving the evolution of clinically destructive cancer traits. We highlight three areas of evolutionary theory with importance to cancer biology that are amenable to experimental evolution: drug resistance, social evolution and resource competition. Understanding the diversity, persistence and evolution of cancers is vital for treatment and drug development, and an experimental evolution approach could provide strategic directions and focus for future research.

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The bewildering complexity of cortical microcircuits at the single cell level gives rise to surprisingly robust emergent activity patterns at the level of laminar and columnar local field potentials (LFPs) in response to targeted local stimuli. Here we report the results of our multivariate data-analytic approach based on simultaneous multi-site recordings using micro-electrode-array chips for investigation of the microcircuitary of rat somatosensory (barrel) cortex. We find high repeatability of stimulus-induced responses, and typical spatial distributions of LFP responses to stimuli in supragranular, granular, and infragranular layers, where the last form a particularly distinct class. Population spikes appear to travel with about 33 cm/s from granular to infragranular layers. Responses within barrel related columns have different profiles than those in neighbouring columns to the left or interchangeably to the right. Variations between slices occur, but can be minimized by strictly obeying controlled experimental protocols. Cluster analysis on normalized recordings indicates specific spatial distributions of time series reflecting the location of sources and sinks independent of the stimulus layer. Although the precise correspondences between single cell activity and LFPs are still far from clear, a sophisticated neuroinformatics approach in combination with multi-site LFP recordings in the standardized slice preparation is suitable for comparing normal conditions to genetically or pharmacologically altered situations based on real cortical microcircuitry.