389 research outputs found

    Supporting a Multi-hierarchical Classifcation in the Object-Oriented Paradigm

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    This research and the resulting prototype system show that the object-oriented paradigm is an appropriate mechanism for supporting a complex, multi-hierarchical controlled vocabulary and the resulting classification when applied to a data base. In addition to supporting such a classification, it allows the searching and browsing of both the data base items and the assigned vocabulary terms

    Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence

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    We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis

    DYNAMIC THRESHOLDING GA-BASED ECG FEATURE SELECTION IN CARDIOVASCULAR DISEASE DIAGNOSIS

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    Electrocardiogram (ECG) data are usually used to diagnose cardiovascular disease (CVD) with the help of a revolutionary algorithm. Feature selection is a crucial step in the development of accurate and reliable diagnostic models for CVDs. This research introduces the dynamic threshold genetic algorithm (DTGA) algorithm, a type of genetic algorithm that is used for optimization problems and discusses its use in the context of feature selection. This research reveals the success of DTGA in selecting relevant ECG features that ultimately enhance accuracy and efficiency in the diagnosis of CVD. This work also proves the benefits of employing DTGA in clinical practice, including a reduction in the amount of time spent diagnosing patients and an increase in the precision with which individuals who are at risk of CVD can be identified

    Pituitary Apoplexy

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    Pituitary apoplexy is a rare clinical emergency due to acute ischemic infarction or hemorrhage of the pituitary gland. As this disorder most often involves a pituitary adenoma, especially nonfunctioning tumors, the syndrome should be referred to as pituitary tumor apoplexy. The precise physiopathology is not completely clear. Although in most cases it occurs spontaneously, pituitary apoplexy can be precipitated by many risk factors. The main symptom is headache of sudden onset associated with visual disturbances, signs of meningeal irritation, and/or endocrine dysfunction. Corticotropic deficiency is a potentially life-threatening disorder. Magnetic resonance imaging is the most sensitive to confirm the diagnosis by revealing a pituitary tumor with hemorrhagic and/or necrotic components. Earlier studies used to consider urgent decompression of the lesion surgically, but nowadays, more recent studies favor conservative management in selected patients (those without important visual acuity or field defects and with normal consciousness). This wait-and-see approach gives evidence of excellent outcomes in terms of oculomotor palsy, pituitary function, and subsequent tumor growth. Surgical decompression may be necessary in some cases. Once the acute phase is over, the patient should be reevaluated for hormonal deficiencies. Moreover, spontaneous remission of syndromes, such as acromegaly, may be caused by pituitary adenoma apoplexy

    Significance of QT dispersion as a diagnosis tool for cardiac patients

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    Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent Univ., 2000.Thesis (Master's) -- Bilkent University, 2000.Includes bibliographical references leaves 73-75.Electrocardiogram (EGG) is the recorded electrical potentials generated by the heart during a cardiac cycle. Gardiac abnormalities cause unknown current flows leading to strange waveform morphologies in the recorded EGG. Some of these abnormalities are only visible when the heart is under stress. Exercise EGG is conducted for this reason. Ischemia is one of the important cardiac abnormalities and is the focus of our study. It occurs when a part of the heart tissue dies or is injured. QT dispersion (QTd) is a proposed method for diagnosing Ischemia. The classical deflnition for QTd is the difference between the maximum and the minimum QT intervals within the 12 leads. In this study the effect of exercise on QT dispersion (QTd) is studied and whether QTd could give significant information for diagnosing patients with ischemic heart disease is investigated. A new method for measuring QT interval is developed and is compared with previous methods. QTd is measured on average beats calculated for 10 seconds intervals throughout the exercise ECG test and a trend curve which we call QTd, is generated. Several decision rules for the diagnosis of cardiac patients are proposed by analyzing these QTd trend curves and the accompanying heart rate curves. It is shown that despite the improvement in QT interval measurements, none of the decision rules proved to be a clinically useful discriminate of cardiac patients, with sufficient confidence.Ben Ahmed Jemel, NabilM.S

    Cerebellar liponeurocytoma with extracranial extension: Case report

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    Cerebellar liponeurocytoma is a newly recognized, rare clinicopathological entity commonly described in the cerebellar hemispheres or the vermis. We present a rare case of cerebellar liponeurocytoma arising from the left cerebellar amygdala with extracranial extension. Such a condition has never been previously reported

    Subependymome du ventricule lateral: presentation d’une serie de 5 cas et revue de la litterature.

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    Description Les subépendymomes sont des tumeurs bénignes rares, de découverte souvent fortuite et siégeant préférentiellement au niveau du quatrième ventricule, plus rarement au niveau du ventricule latéral.Objectif Le but de notre étude est de présenter notre expérience en matière de subépendymomes du ventricule latéral et de discuter leurs caractéristiques cliniques, radiologiques, de prise en charge et pronostiques au vu des données actuelles de la littérature.Méthode Etude rétrospective de cinq cas de subépendymomes symptomatiques du ventricule latéral pris en charge au sein de notre institution au cours des dix dernières années.Résultats Cinq sujets de sexe masculin avec des subépendymomes histologiquement prouvés ont été recensés. L’âge moyen était de 35.2 ans. La présentation clinique allait du début brutal avec aggravation rapide de l’état neurologique aux formes insidieuses avec syndrome d’hypertension intracrânienne évoluant depuis un an. La tumeur était confinée au ventricule latéral dans trois cas et étendue au troisième ventricule dans les deux autres cas avec une taille allant de 12 à 42 mm. L’exérèse complète par un abord trans calleux était réalisée dans tous les cas. L’évolution était favorable avec absence de récidive après un suivi moyen de 6 ans 2 mois.Conclusion Les subépendymomes du ventricule latéral sont rares, avec une symptomatologie variable et une évolution imprévisible. La chirurgie est la modalité thérapeutique de choix et l’exérèse totale doit être envisagée dans tous les cas.Mots clés : Chirurgie, Imagerie par résonance magnétique, Subépendymome, Ventricule latéral, Subépendymome, Ventricule latéra
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