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51.
Summary A mathematical tool for the calculation of the effects of turbulence on acoustic remote-sensing systems is described. The
systems taken into account are sodar, which operates in air, and underwater acoustic Doppler current profilers (ADCP). Included
in the modelling are echo spectrum broadening and the contribution of turbulence to the scattering cross-section. A method
for the measurement of the transverse velocity with a single beam is also suggested. 相似文献
52.
Adriana Vlez Feij Maria Alice Parente Mara Behlau Srgio Haussen Maria Cecília De Veccino Beatriz Castellar de Faria Martignago 《Journal of voice》2004,18(3):341-347
The objective is to investigate the presence of dysphonic symptoms in multiple sclerosis (MS) patients and to compare quantitative acoustic parameters in multiple sclerosis patients and normal individuals. The method of study was an 8-month controlled cross-sectional that was carried out with 106 individuals (30 MS, 76 controls). Both groups included males and females from 20 to 55 years. Exclusion criteria were prior vocal disorder, laryngeal microsurgery, recent endotracheal intubation, tumors, laryngeal, lung or mediastinal metastases, respiratory disease, and other associated neurological diagnoses. For dysphonic symptoms (qualitative variables), associations were assessed using Mantel-Haenszel's chi2 test, with Yates correction or the Fisher exact test when necessary. Statistical significance was set at p< or =0.05. Dysphonia was observed in 70% of MS individuals versus 33% of controls (p=0.01). Association was found between MS and dysphonia (OR: 2.2, CI 95%: 1.13-4.25). Fundamental frequency was higher among MS patients (p=0.01). Fundamental frequency deviation was significantly higher in MS women (but not men) than controls (p=0.00). Jitter was higher in MS men than in all other groups (p=0.00). Results suggest that evaluation and treatment of MS patients should be revised, evaluating voice alterations in relation to other signs. MS seems to intensify gender effect on fundamental frequency deviation, noise, and jitter, with MS women presenting fewer voice variations than men. 相似文献
53.
Julio Marañón 《Physics letters. A》1984,103(3):116-119
One set of non-linear equations of the modified Hückel model is obtained. 相似文献
54.
A general technique for inverting spectral line profiles to obtain physical information about a semi-infinite plasma is described. The technique allows for distinct line and continuum source functions, the presence of both stochastic and systematic velocity fields, and permits all spectral lines in a multiplet to be inverted simultaneously. 相似文献
55.
Ida Cattaneo Gasparini 《Annali di Matematica Pura ed Applicata》1960,50(1):467-473
Sunto Esame delle connessioni infinitesimali nello spazio fibrato dei riferimenti proiettivi di una Vn. Definizione di connessione proiettiva regolare Geodetiche di una Vn secondo una connessione proiettiva con speciale riguardo alle connessioni regolari.
Ad Antonio Signorini nel suo 70mo compleanno. 相似文献
56.
Lauri J. Missio Hugo S. Braibante Mara E. F. Braibante 《Journal of heterocyclic chemistry》1996,33(4):1243-1245
The reactivity of the enamino compounds 4-amino-3-phenylamino(thio)carbonyl-3-penten-2-one 1 and 2 and ethyl 3-amino-2-phenylamino(thio)carbonyl-2-butyrate 7 and 8 was studied using the reaction with hydrazine hydrate and hydrazine hydrochloride to evaluate the 1,3 electrophilic center of the compounds by the formation of the pyrazole rings. The pyrazoles 3, 4, 5, 9, 11 and 13 were obtained depending on the reaction conditions employed. 相似文献
57.
Horacio Grinberg Julio Marañon Hector Vucetich 《Zeitschrift fur Physik C Particles and Fields》1983,20(2):147-149
The Kustaanheimo-Stiefel transformation as applied to the nonrelativistic hydrogen atom provides one of the rare examples of a free particle moving on a four-dimensional homogeneous space. 相似文献
58.
Paolo Manganotti Michele Acler Emanuela Formaggio Mirko Avesani Franco Milanese Andrea Baraldo Silvia Francesca Storti Anna Gasparini Roberto Cerini Roberto Pozzi Mucelli Antonio Fiaschi 《Magnetic resonance imaging》2010
Objective
Whereas several studies have used functional magnetic resonance imaging (fMRI) to investigate motor recovery, whether therapy to decrease post-stroke hypertonus alters central motor patterns remains unclear. In this study, we used continuous electromyography (EMG)-fMRI to investigate possible changes in movement-related brain activation in patients receiving Botulinum toxin (BoNT-A) for hand-muscle hypertonus after chronic stroke.Methods
We studied eight stroke patients all of whom had hemiparesis and associated upper-limb hypertonus. All patients underwent an fMRI-EMG recording and clinical-neurological assessment before BoNT-A and 5 weeks thereafter. The handgrip motor task during imaging was fixed across both patients and controls. The movements were metronome paced, movement amplitude and force were controlled with a plastic orthosis, dynamometer and EMG recording. An age-matched control group was recruited from among healthy volunteers underwent the same fMRI-EMG recording.Results
Before BoNT-A, while patients moved the paretic hand, fMRI detected wide bilateral activation in the sensorymotor areas (SM1), in the supplementary motor area (SMA) and cerebellum. After BoNT-A blood oxygenation level-dependent (BOLD) activation decreased in ipsilateral and contralateral motor areas and became more lateralized. BOLD activation decreased also in ipsilateral cerebellar regions and in the SMA.Conclusion
Changes in peripheral upper-limb hypertonus after BoNT-A were associated to an improvement in active movements and more lateralized and focalized activation of motor areas. The clinical and EMG-fMRI coregistration technique we used to study hand-muscle hypertonus in patients receiving BoNT-A after chronic stroke should be useful in future studies seeking improved strategies for post-stroke neurorehabilitation. 相似文献59.
In the United States, researchers argue that proof is largely concentrated in the domain of high school geometry, thus providing students a distorted image of what proof entails, which is at odds with the central role that proof plays in mathematics. Despite the centrality of proof, there is a lack of studies addressing how to integrate proof into other mathematical domains. In this article, we discuss a teaching experiment designed to integrate algebra and proof in the high school curriculum. Algebraic proof was envisioned as the vehicle that would provide high school students the opportunity to learn not only about proof in a context other than geometry but also about aspects of algebra. Results from the experiment indicate that students meaningfully learned about aspects of both algebra and proof in that they produced algebraic proofs involving multiple variables and a single parameter, based on conjectures they themselves generated. 相似文献
60.
The variations in the chemical compositions of the metallic glasses reported in the literature, as well as the overall lack of experimental data concerning the inhomogeneous deformation behaviour of metallic glass, make the evaluation of the effects of shear band/fracture behaviour on the mechanical properties of metallic glasses difficult. Isolating the effect of local shear band formation on bulk inhomogeneous flow would appear to be a first step in approaching this problem. The mechanical behaviour of Vitreloy metallic glass at room temperature and at various strain rates in tension and compression was investigated. The formation of multiple shear bands was observed at high strain rates. An increase in strain rate leads to enhanced ductility in tension and compression. Some aspects of the deformation processes in tension and compression are discussed. 相似文献