934 resultados para Computer Knowledge Bank on Medical Diagnostics


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New Sr-Nd-Pb-Hf data require the existence of at least four mantle components in the genesis of basalts from the the North Atlantic Igneous Province (NAIP): (1) one (or more likely a small range of) enriched component(s) within the Iceland plume, (2) a depleted component within the Iceland plume (distinct from the shallow N-MORB source), (3) a depleted sheath surrounding the plume and (4) shallow N-MORB source mantle. These components have been available since the major phase of igneous activity associated with plume head impact during Paleogene times. In Hf-Nd isotope space, samples from Iceland, DSDP Leg 49 (Sites 407, 408 and 409), ODP Legs 152 and 163 (southeast Greenland margin), the Reykjanes Ridge, Kolbeinsey Ridge and DSDP Leg 38 (Site 348) define fields that are oblique to the main ocean island basalt array and extend toward a component with higher 176Hf/177Hf than the N-MORB source available prior to arrival of the plume, as indicated by the compositions of Cretaceous basalts from Goban Spur (~95 Ma). Aside from Goban Spur, only basalts from Hatton Bank on the oceanward side of the Rockall Plateau (DSDP Leg 81) lie consistently within the field of N-MORB, which indicates that the compositional influence of the plume did not reach this far south and east ~55 Ma ago. Thus, Hf-Nd isotope systematics are consistent with previous studies which indicate that shallow MORB-source mantle does not represent the depleted component within the Iceland plume (Thirlwall, J. Geol. Soc. London 152 (1995) 991-996; Hards et al., J. Geol. Soc. London 152 (1995) 1003-1009; Fitton et al., 1997 doi:10.1016/S0012-821X(97)00170-2). They also indicate that the depleted component is a long-lived and intrinsic feature of the Iceland plume, generated during an ancient melting event in which a mineral (such as garnet) with a high Lu/Hf was a residual phase. Collectively, these data suggest a model for the Iceland plume in which a heterogeneous core, derived from the lower mantle, consists of 'enriched' streaks or blobs dispersed in a more depleted matrix. A distinguishing feature of both the enriched and depleted components is high Nb/Y for a given Zr/Y (i.e. positive DeltaNb), but the enriched component has higher Sr and Pb isotope ratios, combined with lower epsilon-Nd and epsilon-Hf. This heterogeneous core is surrounded by a sheath of depleted material, similar to the depleted component of the Iceland plume in its epsilon-Nd and epsilon-Hf, but with lower 87Sr/86Sr, 208Pb/204Pb and negative DeltaNb; this material was probably entrained from near the 670 km discontinuity when the plume stalled at the boundary between the upper and lower mantle. The plume sheath displaced more normal MORB asthenosphere (distinguished by its lower epsilon-Hf for a given epsilon-Nd or Zr/Nb ratio), which existed in the North Atlantic prior to plume impact. Preliminary data on MORBs from near the Azores plume suggest that much of the North Atlantic may be 'polluted' not only by enriched plume material but also by depleted material similar to the Iceland plume sheath. If this hypothesis is correct, it may provide a general explanation for some of the compositional diversity and variations in inferred depth of melting (Klein and Langmuir, 1987 doi:10.1029/JB092iB08p08089) along the MAR in the North Atlantic.

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Calcareous nannofossil assemblages recovered in four Islas Orcadas piston cores along the northern margin of the Maurice Ewing Bank on the eastern Falkland Plateau are correlated with lower Oligocene and middle Eocene sections at Deep Sea Drilling Project Sites 511 and 512, respectively. Results indicate that the Paleogene section near the piston core stations is generally more calcareous and complete than at the Leg 71 drill sites and could provide a valuable highlatitude biostratigraphic reference locality if drilled at some future date.

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Who invents medicines for the poor of the world? This question becomes very important where the WTO allows low income countries to be unbound by the TRIPS agreement. This agreement concerns medicines for infectious diseases such as HIV/AIDS, tuberculosis and malaria. These diseases cause serious damage to low income countries. Under these circumstances, some scholars wonder if anyone will continue innovative activities related to treating these diseases. This paper sought to answer this question by collecting and analyzing patent data of medicines and vaccines for diseases using the database of the Japan Patent Office. Results indicate that private firms have led in innovation not only for global diseases such as HIV/AIDS but also diseases such as malaria that are spreading exclusively in low income countries. Innovation for the three infectious diseases is diverse among firms, and frequent patent applications by high-performing pharmaceutical firms appear prominent even after R&D expenditure, economies of scale, and economies of scope are taken into account.

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This Doctoral Thesis entitled Contribution to the analysis, design and assessment of compact antenna test ranges at millimeter wavelengths aims to deepen the knowledge of a particular antenna measurement system: the compact range, operating in the frequency bands of millimeter wavelengths. The thesis has been developed at Radiation Group (GR), an antenna laboratory which belongs to the Signals, Systems and Radiocommunications department (SSR), from Technical University of Madrid (UPM). The Radiation Group owns an extensive experience on antenna measurements, running at present four facilities which operate in different configurations: Gregorian compact antenna test range, spherical near field, planar near field and semianechoic arch system. The research work performed in line with this thesis contributes the knowledge of the first measurement configuration at higher frequencies, beyond the microwaves region where Radiation Group features customer-level performance. To reach this high level purpose, a set of scientific tasks were sequentially carried out. Those are succinctly described in the subsequent paragraphs. A first step dealed with the State of Art review. The study of scientific literature dealed with the analysis of measurement practices in compact antenna test ranges in addition with the particularities of millimeter wavelength technologies. Joint study of both fields of knowledge converged, when this measurement facilities are of interest, in a series of technological challenges which become serious bottlenecks at different stages: analysis, design and assessment. Thirdly after the overview study, focus was set on Electromagnetic analysis algorithms. These formulations allow to approach certain electromagnetic features of interest, such as field distribution phase or stray signal analysis of particular structures when they interact with electromagnetic waves sources. Properly operated, a CATR facility features electromagnetic waves collimation optics which are large, in terms of wavelengths. Accordingly, the electromagnetic analysis tasks introduce an extense number of mathematic unknowns which grow with frequency, following different polynomic order laws depending on the used algorithmia. In particular, the optics configuration which was of our interest consisted on the reflection type serrated edge collimator. The analysis of these devices requires a flexible handling of almost arbitrary scattering geometries, becoming this flexibility the nucleus of the algorithmia’s ability to perform the subsequent design tasks. This thesis’ contribution to this field of knowledge consisted on reaching a formulation which was powerful at the same time when dealing with various analysis geometries and computationally speaking. Two algorithmia were developed. While based on the same principle of hybridization, they reached different order Physics performance at the cost of the computational efficiency. Inter-comparison of their CATR design capabilities was performed, reaching both qualitative as well as quantitative conclusions on their scope. In third place, interest was shifted from analysis - design tasks towards range assessment. Millimetre wavelengths imply strict mechanical tolerances and fine setup adjustment. In addition, the large number of unknowns issue already faced in the analysis stage appears as well in the on chamber field probing stage. Natural decrease of dynamic range available by semiconductor millimeter waves sources requires in addition larger integration times at each probing point. These peculiarities increase exponentially the difficulty of performing assessment processes in CATR facilities beyond microwaves. The bottleneck becomes so tight that it compromises the range characterization beyond a certain limit frequency which typically lies on the lowest segment of millimeter wavelength frequencies. However the value of range assessment moves, on the contrary, towards the highest segment. This thesis contributes this technological scenario developing quiet zone probing techniques which achieves substantial data reduction ratii. Collaterally, it increases the robustness of the results to noise, which is a virtual rise of the setup’s available dynamic range. In fourth place, the environmental sensitivity of millimeter wavelengths issue was approached. It is well known the drifts of electromagnetic experiments due to the dependance of the re sults with respect to the surrounding environment. This feature relegates many industrial practices of microwave frequencies to the experimental stage, at millimeter wavelengths. In particular, evolution of the atmosphere within acceptable conditioning bounds redounds in drift phenomena which completely mask the experimental results. The contribution of this thesis on this aspect consists on modeling electrically the indoor atmosphere existing in a CATR, as a function of environmental variables which affect the range’s performance. A simple model was developed, being able to handle high level phenomena, such as feed - probe phase drift as a function of low level magnitudes easy to be sampled: relative humidity and temperature. With this model, environmental compensation can be performed and chamber conditioning is automatically extended towards higher frequencies. Therefore, the purpose of this thesis is to go further into the knowledge of millimetre wavelengths involving compact antenna test ranges. This knowledge is dosified through the sequential stages of a CATR conception, form early low level electromagnetic analysis towards the assessment of an operative facility, stages for each one of which nowadays bottleneck phenomena exist and seriously compromise the antenna measurement practices at millimeter wavelengths.

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El objetivo de este proyecto ha sido el de realizar un análisis del importante desarrollo que han sufrido las telecomunicaciones, haciendo un especial hincapié en la telefonía móvil y el impacto y repercusión que ha causado actualmente en nuestra sociedad. Para ello se hará un repaso evolutivo de las tecnologías de la información y las telecomunicaciones, y se establecerá una relación entre la gran difusión de éstas y su efecto sobre los usos, y cambios percibidos por los consumidores del nuevo siglo. Ciertamente la historia de la tecnología, nos enseña que la gente y las organizaciones acaban utilizándola para unos propósitos muy diferentes de aquellos que inicialmente fueron concebidas. Además cuanto más interactiva sea una tecnología, tanto más probable será que los usuarios se conviertan en productores o modificadores de la misma. Por tanto, la sociedad necesita resolver las incógnitas que pueda suscitar el rápido y continúo cambio de las comunicaciones. Este proyecto trata de ayudar a responder alguna de las cuestiones que actualmente se están planteando. ¿Son los teléfonos móviles una expresión de identidad, artilugios de moda, herramientas de la vida cotidiana, o todo lo anterior? ¿Existen nuevos modelos de comportamiento y conducta social? ¿La comunicación móvil está favoreciendo la aparición de una nueva cultura joven con un lenguaje propio basado en la comunicación textual y multimodal? ¿Tienen los teléfonos móviles efectos nocivos en la salud? La respuesta a estas preguntas afecta a nuestras vidas y también condiciona las políticas públicas y las estrategias de negocio, por eso requiere adquirir un conocimiento cimentado en la información, y la recopilación de datos de diversas fuentes, tanto de estadísticas provenientes de diferentes estudios e investigaciones, como de empresas consultoras, siempre basada en una perspectiva global. En conjunto, se espera dentro de los límites del conocimiento actual, contribuir a establecer las bases para el análisis y valoración de la relación existente entre comunicación, tecnología y sociedad en todo el mundo. Abstract The purpose of this project has been to analyse the significant development undergone by telecommunications, putting a special emphasis on mobile phones and the impact it has caused in society. We will go over the evolution of IT technologies and telecommunications as well as establish a relationship between its spread and effect of its uses and changes understood by the new century consumers. Technology history shows us that people and organizations use it for very different purposes from those originally thought. Furthermore, the more interactive technologies are, the more users will modify or produce it. Therefore, society needs to solve the mysteries of the quick and continuous change of communications. This project tries to help and answer some of the questions considered these days. Are mobile phones an expression of identity, fashionable devices, tools for everyday life or all at once? Are there any new models of performance and social behaviour? Is mobile communication favouring the existence of a new young culture with a typical language based on textual and multimodal communication? Are mobile phones bad for our health? The answer to these questions affects us all and conditions public politics and business strategies so it is required to get firm knowledge based on information. It is also important to compile data from various sources, from statistics of research and studies, based on a global perspective. As a whole, we hope to contribute to establish the bases for the future analysis and assessment of a fundamental trend that is redefining the relationship between communication, technology and society worldwide by transforming the wireless networks that make our lives.

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This work deals with quality level prediction in concrete structures through the helpful assistance of an expert system wich is able to apply reasoning to this field of structural engineering. Evidences, hypotheses and factors related to this human knowledge field have been codified into a Knowledge Base in terms of probabilities for the presence of either hypotheses or evidences,and conditional presence of both. Human experts in structural engineering and safety of structures gave their invaluable knowledge and assistance necessary when constructing the "computer knowledge body".

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Respiratory motion is a major source of reduced quality in positron emission tomography (PET). In order to minimize its effects, the use of respiratory synchronized acquisitions, leading to gated frames, has been suggested. Such frames, however, are of low signal-to-noise ratio (SNR) as they contain reduced statistics. Super-resolution (SR) techniques make use of the motion in a sequence of images in order to improve their quality. They aim at enhancing a low-resolution image belonging to a sequence of images representing different views of the same scene. In this work, a maximum a posteriori (MAP) super-resolution algorithm has been implemented and applied to respiratory gated PET images for motion compensation. An edge preserving Huber regularization term was used to ensure convergence. Motion fields were recovered using a B-spline based elastic registration algorithm. The performance of the SR algorithm was evaluated through the use of both simulated and clinical datasets by assessing image SNR, as well as the contrast, position and extent of the different lesions. Results were compared to summing the registered synchronized frames on both simulated and clinical datasets. The super-resolution image had higher SNR (by a factor of over 4 on average) and lesion contrast (by a factor of 2) than the single respiratory synchronized frame using the same reconstruction matrix size. In comparison to the motion corrected or the motion free images a similar SNR was obtained, while improvements of up to 20% in the recovered lesion size and contrast were measured. Finally, the recovered lesion locations on the SR images were systematically closer to the true simulated lesion positions. These observations concerning the SNR, lesion contrast and size were confirmed on two clinical datasets included in the study. In conclusion, the use of SR techniques applied to respiratory motion synchronized images lead to motion compensation combined with improved image SNR and contrast, without any increase in the overall acquisition times.

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A novel method for generating patient-specific high quality conforming hexahedral meshes is presented. The meshes are directly obtained from the segmentation of patient magnetic resonance (MR) images of abdominal aortic aneu-rysms (AAA). The MRI permits distinguishing between struc-tures of interest in soft tissue. Being so, the contours of the lumen, the aortic wall and the intraluminal thrombus (ILT) are available and thus the meshes represent the actual anato-my of the patient?s aneurysm, including the layered morpholo-gies of these structures. Most AAAs are located in the lower part of the aorta and the upper section of the iliac arteries, where the inherent tortuosity of the anatomy and the presence of the ILT makes the generation of high-quality elements at the bifurcation is a challenging task. In this work we propose a novel approach for building quadrilateral meshes for each surface of the sectioned geometry, and generating conforming hexahedral meshes by combining the quadrilateral meshes. Conforming hexahedral meshes are created for the wall and the ILT. The resulting elements are evaluated on four patients? datasets using the Scaled Jacobian metric. Hexahedral meshes of 25,000 elements with 94.8% of elements well-suited for FE analysis are generated.

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Schizophrenia is a mental disorder characterized by a breakdown of cognitive processes and by a deficit of typi-cal emotional responses. Effectiveness of computerized task has been demonstrated in the field of cognitive rehabilitation. However, current rehabilitation programs based on virtual environments normally focus on higher cognitive functions, not covering social cognition training. This paper presents a set of video-based tasks specifically designed for the rehabilita-tion of emotional processing deficits in patients in early stages of schizophrenia or schizoaffective disorders. These tasks are part of the Mental Health program of Guttmann NeuroPer-sonalTrainer® cognitive tele-rehabilitation platform, and entail innovation both from a clinical and technological per-spective in relation with former traditional therapeutic con-tents.

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This paper proposes a first approach to Objective Motor Assessment (OMA) methodology. Also, it introduces the Dysfunctional profile (DP) concept. DP consists of a data matrix characterizing the Upper Limb (UL) physical alterations of a patient with Acquired Brain Injury (ABI) during the rehabilitation process. This research is based on the comparison methology of UL movement between subjects with ABI and healthy subjects as part of OMA. The purpose of this comparison is to classify subjects according to their motor control and subsequently issue a functional assessment of the movement. For this purpose Artificial Neural Networks (ANN) have been used to classify patients. Different network structures are tested. The obtained classification accuracy was 95.65%. This result allows the use of ANNs as a viable option for dysfunctional assessment. This work can be considered a pilot study for further research to corroborate these results.

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Acquired Brain Injury (ABI) has become one of the most common causes of neurological disability in developed countries. Cognitive disorders result in a loss of independence and therefore patients? quality of life. Cognitive rehabilitation aims to promote patients? skills to achieve their highest degree of personal autonomy. New technologies such as interactive video, whereby real situations of daily living are reproduced within a controlled virtual environment, enable the design of personalized therapies with a high level of generalization and a great ecological validity. This paper presents a graphical tool that allows neuropsychologists to design, modify, and configure interactive video therapeutic activities, through the combination of graphic and natural language. The tool has been validated creating several Activities of Daily Living and a preliminary usability evaluation has been performed showing a good clinical acceptance in the definition of complex interactive video therapies for cognitive rehabilitation.

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Automatic blood glucose classification may help specialists to provide a better interpretation of blood glucose data, downloaded directly from patients glucose meter and will contribute in the development of decision support systems for gestational diabetes. This paper presents an automatic blood glucose classifier for gestational diabetes that compares 6 different feature selection methods for two machine learning algorithms: neural networks and decision trees. Three searching algorithms, Greedy, Best First and Genetic, were combined with two different evaluators, CSF and Wrapper, for the feature selection. The study has been made with 6080 blood glucose measurements from 25 patients. Decision trees with a feature set selected with the Wrapper evaluator and the Best first search algorithm obtained the best accuracy: 95.92%.

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The present work covers the first validation efforts of the EVA Tracking System for the assessment of minimally invasive surgery (MIS) psychomotor skills. Instrument movements were recorded for 42 surgeons (4 expert, 22 residents, 16 novice medical students) and analyzed for a box trainer peg transfer task. Construct validation was established for 7/9 motion analysis parameters (MAPs). Concurrent validation was determined for 8/9 MAPs against the TrEndo Tracking System. Finally, automatic determination of surgical proficiency based on the MAPs was sought by 3 different approaches to supervised classification (LDA, SVM, ANFIS), with accuracy results of 61.9%, 83.3% and 80.9% respectively. Results not only reflect on the validation of EVA for skills? assessment, but also on the relevance of motion analysis of instruments in the determination of surgical competence.