214 resultados para Nonparametric regression techniques
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Recent advances have allowed the development of new physical techniques in neurology and psychiatry, such as Transcranial Magnetic Stimulation (TMS), Vagus Nerve Stimulation (VNS), and Deep Brain Stimulation (DBS). These techniques are already recognized as therapeutic approaches in several late stage refractory neurological disorders (Parkinson's disease, tremor, epilepsy), and currently investigated in psychiatric conditions, refractory to medical treatment (obsessive-compulsive disorder, resistant major depression). In Paralell, these new techniques offer a new window to understand the neurobiology of human behavior.
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In order to prevent adjacent segment degeneration following spinal fusion new techniques are being used. Lumbar disc arthroplasty yields mid term results equivalent to those of spinal fusion. Cervical disc arthroplasty is indicated in the treatment of cervicobrachialgia with encouraging initial results. The ability of arthroplasty to prevent adjacent segment degeneration has yet to be proven. Although dynamic stabilization had not been proven effective in treating chronic low back pain, it might be useful following decompression of lumbar spinal stenosis in degenerative spondylolisthesis. Interspinal devices are useful in mild lumbar spinal stenosis but their efficacy in treating low back pain is yet to be proven. Confronted with a growing number of new technologies clinicians should remain critical while awaiting long term results.
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PURPOSE OF REVIEW: Recent findings in the physiology and neurobiology of ejaculation have expanded our understanding of male sexual function and have allowed the development of new instruments to investigate ejaculatory and orgasmic disorders. RECENT FINDINGS: The evidence-based definition of lifelong premature ejaculation has set a model in the evaluation and treatment outcome of sexual dysfunction. New instruments to objectively assess arousal, orgasm and the expulsion phase of ejaculation such as functional MRI, dynamic pelvic ultrasound, PET scans and validated questionnaires have lead to a better understanding of sexual dysfunction in men. Animal models, developments in neurobiology and clinical experience have transformed a purely psychoanalytical approach to ejaculatory and orgasmic function into a novel multidisciplinary, scientifically sound and evidence-based discipline of medicine. SUMMARY: Ejaculation is an integral part of normal sexual function. Ejaculatory dysfunction is common and may cause substantial disruption to the quality of a patient's life. A better understanding of the epidemiology, pathophysiology, neuroscience and genetics of ejaculatory and orgasmic function will eventually lead to the development of new, effective methods of treatment of disorders of ejaculation and orgasm in men.
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BACKGROUND AND PURPOSE: Knowledge of cerebral blood flow (CBF) alterations in cases of acute stroke could be valuable in the early management of these cases. Among imaging techniques affording evaluation of cerebral perfusion, perfusion CT studies involve sequential acquisition of cerebral CT sections obtained in an axial mode during the IV administration of iodinated contrast material. They are thus very easy to perform in emergency settings. Perfusion CT values of CBF have proved to be accurate in animals, and perfusion CT affords plausible values in humans. The purpose of this study was to validate perfusion CT studies of CBF by comparison with the results provided by stable xenon CT, which have been reported to be accurate, and to evaluate acquisition and processing modalities of CT data, notably the possible deconvolution methods and the selection of the reference artery. METHODS: Twelve stable xenon CT and perfusion CT cerebral examinations were performed within an interval of a few minutes in patients with various cerebrovascular diseases. CBF maps were obtained from perfusion CT data by deconvolution using singular value decomposition and least mean square methods. The CBF were compared with the stable xenon CT results in multiple regions of interest through linear regression analysis and bilateral t tests for matched variables. RESULTS: Linear regression analysis showed good correlation between perfusion CT and stable xenon CT CBF values (singular value decomposition method: R(2) = 0.79, slope = 0.87; least mean square method: R(2) = 0.67, slope = 0.83). Bilateral t tests for matched variables did not identify a significant difference between the two imaging methods (P >.1). Both deconvolution methods were equivalent (P >.1). The choice of the reference artery is a major concern and has a strong influence on the final perfusion CT CBF map. CONCLUSION: Perfusion CT studies of CBF achieved with adequate acquisition parameters and processing lead to accurate and reliable results.
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What determines the share of public employment, at a given size of the State, in countries of similar levels of economic development? While the theoretical and empirical literature on this issue has mostly considered technical dimensions (efficiency and political considerations), this paper emphasizes the role of culture and quantifies it. We build a representative database for contracting choices of municipalities in Switzerland and exploit the discontinuity at the Swiss language border at identical actual set of policies and institutions to analyze the causal e↵ect of culture on the choice of how public services are provided. We find that French-speaking border municipalities are 50% less likely to contract with the private sector than their German-speaking adjacent municipalities. Technical dimensions are much smaller by comparison. This result points out that culture is a source of a potential bias that distorts the optimal choice for public service delivery. Systematic differences in the level of confidence in public administration and private companies potentially explain this discrepancy in private sector participation in public services provision.
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Résumé : Ce travail comprend deux parties : La première partie a pour but de présenter une revue des techniques de gastrostomie chez l'enfant. La gastrostomie est, par définition, un tractus fistuleux entre l'estomac et la paroi abdominale. Le but de la gastrostomie est de permettre la décompression gastrique, la nutrition entérale et l'apport médicamenteux. Les indications et contre-indications à la confection et utilisation de la gastrostomie sont détaillées dans ce travail. Historiquement, les premières gastrostomies étaient d'origine accidentelle ou infectieuse (fistule gastro-cutanée), incompatibles avec la vie. Sedillot, en 1845 décrivit la première gastrostomie chirurgicale sans cathéter, qui avait comme désavantage la présence de fuites. Depuis, les techniques se sont multipliées en évoluant vers la continence et l'utilisation de cathéters. En 1979 Gauderer décrivit pour la première fois une technique percutanée, réalisée sur un enfant âgé de 5 mois. Cette technique est appelée « Percutaneous Endoscopic Gastrostomy » (PEG). Elle a ensuite été élargie à la population adulte. Actuellement, il existe une grande multiplicité de techniques par abord « laparotomique », laparoscopique ou percutanée (endoscopique ou radiologique). Ces techniques peuvent être combinées. Toutes ces techniques nécessitent la présence intermittente ou continue d'un dispositif, qui permet le maintient de la gastrostomie ouverte et évite les fuites gastriques. Ces dispositifs sont multiples; initialement il s'agissait de cathéters rigides (bois, métal, caoutchouc). Ensuite ils ont été fabriqués en silicone, ce qui les rend plus souples et mieux tolérés par le patient. Pour éviter leur dislocation, ils possèdent un système d'amarrage intra-gastrique tel que : un champignon (Bard®), un ballonnet (Foley®, Mic-Key®), ou une forme spiralée du cathéter (« pig-tail ») et possèdent un système d'amarrage extra-gastrique (« cross-bar »). En 1982, Gauderer créa le premier dispositif à fleur de peau : le bouton de gastrostomie (BG). Actuellement, il en existe deux types : à champignon (Bard®) et à ballonnet (Mic-Key®). Il existe plusieurs types de complications liées à la technique opératoire, à la prise en charge et au matériel utilisé. Une comparaison des différentes techniques, matériaux utilisés et coûts engendrés est détaillée dans ce travail. La deuxième partie de ce travail est dédiée aux BG et plus spécifiquement au BG à ballonnet (Mic-Key®). Nous présentons les différents boutons et les techniques spécifiques. Le BG est inséré soit dans une gastrostomie préformée, soit directement lors de la confection d'une gastrostomie par laparotomie, laparoscopie ou de façon percutanée. Les complications liées au BG sont rapportées. D'autres utilisations digestives ou urologiques sont décrites. Nous présentons ensuite notre expérience avec 513 BG à ballonnet (Mic-Key®) dans une revue de 73 enfants. La pose du BG est effectuée dans une gastrostomie préformée sans recours à une anesthésie générale. La technique choisie pour la confection de la gastrostomie dépend de la pathologie de base, de l'état général du patient, de la nécessité d'une opération concomitante et du risque anesthésique. Nous apportons des précisions sur le BG telles que la dimension en fonction de l'âge, la durée de vie, et les causes qui ont amené au changement du BG. Nos résultats sont comparés à ceux de la littérature. Sur la base de notre expérience et après avoir passé en revue la littérature spécialisée, nous proposons des recommandations sur le choix de la technique et le choix du matériel. Ce travail se termine avec une réflexion sur le devenir de la gastrostomie. Si le futur consiste à améliorer et innover les techniques et les matériaux, des protocoles destinés à la standardisation des techniques, à la sélection des patients et à l'enseignement des soins devraient s'en suivre. La prise en charge de l'enfant ne se limite pas à la sélection appropriée de la technique et des matériaux, mais il s'agit avant tout d'une approche multidisciplinaire. La collaboration entre le personnel soignant, la famille et l'enfant est essentielle pour que la prise en charge soit optimale et sans risques.
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Genetics is the study of heredity, which means the study of genes and factors related to all aspects of genes. The scientific history of genetics began with the works of Gregor Mendel in the mid-19th century. Prior to Mendel, genetics was primarily theoretical whilst, after Mendel, the science of genetics was broadened to include experimental genetics. Developments in all fields of genetics and genetic technology in the first half of the 20th century provided a basis for the later developments. In the second half of the 20th century, the molecular background of genetics has become more understandable. Rapid technological advancements, followed by the completion of Human Genome Project, have contributed a great deal to the knowledge of genetic factors and their impact on human life and diseases. Currently, more than 1800 disease genes have been identified, more than 2000 genetic tests have become available, and in conjunction with this at least 350 biotechnology-based products have been released onto the market. Novel technologies, particularly next generation sequencing, have dramatically accelerated the pace of biological research, while at the same time increasing expectations. In this paper, a brief summary of genetic history with short explanations of most popular genetic techniques is given.