990 resultados para P(x)-laplacian Problem


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Phase sensitive X-ray imaging methods can provide substantially increased contrast over conventional absorption-based imaging and therefore new and otherwise inaccessible information. The use of gratings as optical elements in hard X-ray phase imaging overcomes some of the problems that have impaired the wider use of phase contrast in X-ray radiography and tomography. So far, to separate the phase information from other contributions detected with a grating interferometer, a phase-stepping approach has been considered, which implies the acquisition of multiple radiographic projections. Here we present an innovative, highly sensitive X-ray tomographic phase-contrast imaging approach based on grating interferometry, which extracts the phase-contrast signal without the need of phase stepping. Compared to the existing phase-stepping approach, the main advantages of this new method dubbed "reverse projection" are not only the significantly reduced delivered dose, without the degradation of the image quality, but also the much higher efficiency. The new technique sets the prerequisites for future fast and low-dose phase-contrast imaging methods, fundamental for imaging biological specimens and in vivo studies.

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A patent processus vaginalis peritonei (PPV) presents typically as an indirect hernia with an intact inguinal canal floor during childhood. Little is known however about PPV in adults and its best treatment. A cohort study included all consecutive patients admitted for ambulatory open hernia repair. In patients with a PPV, demographics, hernia characteristics, and outcome were prospectively assessed. Annulorrhaphy was the treatment of choice in patients with an internal inguinal ring diameter of < 30 mm. Between 1998 and 2006, 92 PPVs (two bilateral) were diagnosed in 676 open hernia repairs (incidence of 14%). Eighty nine of the 90 patients were males, the median age was 34 years (range: 17-85). A PPV was right-sided in 67% and partially obliterated in 66%. Forty-one patients had an annulorrhaphy and 51 patients had a tension-free mesh repair. The median operation time was significantly shorter in the annulorrhaphy group (38 vs. 48 min, P <.0001). In a median follow-up period of 56 months (27-128), both groups did not differ concerning recurrence (1/41 vs. 2/51), chronic pain (3/41 vs. 4/51), and hypoesthesia (5/41 vs. 9/51). There was however a clear trend to less neuropathic symptoms in favor of annulorrhaphy (0/41 vs. 5/51, P < 0.066). PPV occurs in 14% of adults undergoing hernia repair. In selected patients, annulorrhaphy takes less time and is associated with equally low recurrence but less potential for neuropathic symptoms.

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In clinical practice, a classification of seizures based on clinical signs and symptoms leads to an improved understanding of epilepsy-related issues and therefore strongly contributes to a better patient care. The inverse problem involves inferring the anatomical brain localization of a seizure from the scalp surface EEG, a concept we apply here to correlate seizure origin with seizure semiology. The spheres of sensorium, motor features, consciousness changes and autonomic alterations during ictal and postictal manifestations are reviewed, including several subdivisions used to better categorize particular features. Particular attention is given to behavioral features, as well as to features occurring in idiopathic generalized epileptic syndromes and psychogenic nonepileptic spells.

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Recently, modern cross-sectional imaging techniques such as multi-detector computed tomography (MDCT) have pioneered post mortem investigations, especially in forensic medicine. Such approaches can also be used to investigate bones non-invasively for anthropological purposes. Long bones are often examined in forensic cases because they are frequently discovered and transferred to medico-legal departments for investigation. To estimate their age, the trabecular structure must be examined. This study aimed to compare the performance of MDCT with conventional X-rays to investigate the trabecular structure of long bones. Fifty-two dry bones (24 humeri and 28 femora) from anthropological collections were first examined by conventional X-ray, and then by MDCT. Trabecular structure was evaluated by seven observers (two experienced and five inexperienced in anthropology) who analyzed images obtained by radiological methods. Analyses contained the measurement of one quantitative parameter (caput diameter of humerus and femur) and staging the trabecular structure of each bone. Preciseness of each technique was indicated by describing areas of trabecular destruction and particularities of the bones, such as pathological changes. Concerning quantitative parameters, the measurements demonstrate comparable results for the MDCT and conventional X-ray techniques. In contrast, the overall inter-observer reliability of the staging was low with MDCT and conventional X-ray. Reliability increased significantly when only the results of the staging performed by the two experienced observers were compared, particularly regarding the MDCT analysis. Our results also indicate that MDCT appears to be better suited to a detailed examination of the trabecular structure. In our opinion, MDCT is an adequate tool with which to examine the trabecular structure of long bones. However, adequate methods should be developed or existing methods should be adapted to MDCT.

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PURPOSE: The current study tested the applicability of Jessor's problem behavior theory (PBT) in national probability samples from Georgia and Switzerland. Comparisons focused on (1) the applicability of the problem behavior syndrome (PBS) in both developmental contexts, and (2) on the applicability of employing a set of theory-driven risk and protective factors in the prediction of problem behaviors. METHODS: School-based questionnaire data were collected from n = 18,239 adolescents in Georgia (n = 9499) and Switzerland (n = 8740) following the same protocol. Participants rated five measures of problem behaviors (alcohol and drug use, problems because of alcohol and drug use, and deviance), three risk factors (future uncertainty, depression, and stress), and three protective factors (family, peer, and school attachment). Final study samples included n = 9043 Georgian youth (mean age = 15.57; 58.8% females) and n = 8348 Swiss youth (mean age = 17.95; 48.5% females). Data analyses were completed using structural equation modeling, path analyses, and post hoc z-tests for comparisons of regression coefficients. RESULTS: Findings indicated that the PBS replicated in both samples, and that theory-driven risk and protective factors accounted for 13% and 10% in Georgian and Swiss samples, respectively in the PBS, net the effects by demographic variables. Follow-up z-tests provided evidence of some differences in the magnitude, but not direction, in five of six individual paths by country. CONCLUSION: PBT and the PBS find empirical support in these Eurasian and Western European samples; thus, Jessor's theory holds value and promise in understanding the etiology of adolescent problem behaviors outside of the United States.

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Molar heat capacities of the binary compounds NiAl, NiIn, NiSi, NiGe, NiBi, NiSb, CoSb and FeSb were determined every 10 K by differential scanning calorimetry in the temperature range 310-1080 K. The experimental results have been fitted versus temperature according to C-p = a + b . T + c . T-2 + d . T-2. Results are given, discussed and compared to estimations found in the literature. Two compounds, NiBi and FeSb, are subject to transformations between 460 and 500 K. (C) 1999 Elsevier Science Ltd. All rights reserved.

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Comprend : [Portrait en frontispice : portrait de l'auteur, Goethe.] Goethe, d'après le tableau de May (1779). [Cote : 4 ° Yh 6/Microfilm R 122282] ; [Vignette à la page de titre : marque d'imprimeur avec devise et initiales.] Pictoribus atque Poetis. Occupa Portum. D.J. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. du Prologue p.11 : dans le ciel, l'archange Gabriel et Méphistophélès.] Prologue. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. p.52. : Faust dans son cabinet d'étude avec son chien Barbet qui grandit et gonfle, habité par Méphistophélès.] Le barbet. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. p.102 : Faust dans la cuisine de la sorcière, devant un chaudron, ayant la vision d'une femme nue.] La vision. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. p.141 : Marguerite et Faust se promènent dans un jardin. Au loin, Marthe et Méphistophélès.] Le jardin. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. p.214 : Faust rejoint Marguerite dans son cachot.] La prison. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282] ; [pl. en reg. p.222 : Marguerite, ayant sauvé son âme, est présentée par l'archange Gabriel à Dieu. Elle tient dans ses bras son fils mort, noyé.] Epilogue. Faust. [Cote : 4 ° Yh 6/Microfilm R 122282]

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Comprend : [Tome I. Bandeau à la Dédicace : lion et licorne entourant les armoiries et la devise du Duc de Glocester.] Honi soit qui mal y pense. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. folio B : la Thébaïde ou les frères ennemis. Tragédie.] Thébaïde. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. du titre de la tragédie Alexandre le grand :] Alexandre. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. du titre de la tragédie Andromaque :] Andromaque. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. du titre de la tragédie Britannicus :] Britannicus. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. du titre de la tragédie Berenice :] Berenice. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome I. Pl. en reg. du titre de la comédie Les Plaideurs :] Les Plaideurs. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Frontispice :] [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Bajazet :] Bajazet. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Mithridate :] Mithridate. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Iphigénie :] Iphigénie. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Phèdre :] Phèdre. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Esther :] Esther. [Cote : Yf 404-405/Microfilm R 122414] ; [Tome II. Pl. en reg. du titre de la tragédie Athalie :] Athalie. [Cote : Yf 404-405/Microfilm R 122414]