نتایج جستجو برای: flutter
تعداد نتایج: 4720 فیلتر نتایج به سال:
Ocular flutter is an eye movement disorder characterized by purely horizontal rapid saccadic oscillations lasting for a few minutes which stops spontaneously. Postinfectious ocular flutter and truncal ataxia are a rare entity. There are reported cases of opsoclonus myoclonus ataxia in association with dengue virus infection. However, there are no reported cases of parainfectious ocular flutter ...
Tonal, non-vocal sounds are widespread in both ordinary bird flight and communication displays. We hypothesized these sounds are attributable to an aerodynamic mechanism intrinsic to flight feathers: aeroelastic flutter. Individual wing and tail feathers from 35 taxa (from 13 families) that produce tonal flight sounds were tested in a wind tunnel. In the wind tunnel, all of these feathers could...
Feathers can produce sound by fluttering in airflow. This flutter is hypothesized to be aeroelastic, arising from the coupling of aerodynamic forces to one or more of the feather's intrinsic structural resonance frequencies. We investigated how mode of flutter varied among a sample of hummingbird tail feathers tested in a wind tunnel. Feather vibration was measured directly at ~100 points acros...
This study identifies the control parameters which critically influence the development of intermodal coupling and the generation of aerodynamic damping, based on closed-form solutions of bimodal coupled analysis of bridge aerolastic system. This information helps in developing a guideline for the selection of most critical structural modes in a coupled flutter analysis and in better interpreta...
OBJECTIVE To examine the effect of exercise on cycle length in atrial flutter. PATIENTS 15 patients with chronic atrial flutter. Seven patients were taking digoxin and six verapamil; two were not taking medication. METHODS All patients underwent bicycle ergometry. Flutter cycle length was measured at rest and at peak exercise. RESULTS Mean flutter cycle length increased from 245 ms to 256...
Atrial fibrillation and atrial flutter share a common reentrant mechanism. However, the relationship between these arrhythmias has not been systemically studied to date. To evaluate the degree to which these arrhythmias may alternate, consecutive Holter monitor recordings which showed fibrillation or flutter in 96 patients were reviewed. One half of the patients were studied after open-heart su...
OBJECTIVE To determine whether echocardiographic markers thromboembolic risk differ between patients with pure atrial flutter and patients with atrial flutter and intermittent atrial fibrillation. DESIGN Patients with atrial flutter were followed up prospectively for 12 months to identify intermittent atrial fibrillation. After the follow up period, transthoracic and multiplane transoesophage...
An experimental model of a typical three degree-of-freedom airfoil section with composite control surface subjected to a two-dimensional, incompressible air-flow has been created. The flutter response of the system with both, a defect-free and with damaged control surfaces, were measured experimentally. An analytical model was implemented to predict the flutter response in the case of a defect-...
Background Slight variation in cycle lengths of common and rapid atrial flutter in humans is an established phenomenon, but its mechanisms have not been completely clarified. In a previous study, we demonstrated that in common atrial flutter the variations in atrial cycle length were due to atrial stretch affecting the revolution time of a reentrant circuit. In the present study, we investigate...
BACKGROUND Acute effects of class I and class III antiarrhythmia drugs on the reentrant circuit of typical atrial flutter are not fully studied. Furthermore, the critical electrophysiologic determinants of flutter termination by antiarrhythmia drugs are not clear. METHODS AND RESULTS The study population consisted of 36 patients (mean age, 53+/-17 years) with clinically documented typical atr...
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