During courtship flights, males of some hummingbird species produce diverse sounds with tail feathers of varying shapes. We show that these sounds are produced by air flowing past a feather, causing it to aeroelastically flutter and generate flutter-induced sound. Scanning laser doppler vibrometery and high-speed video of individual feathers of different sizes and shapes in a wind tunnel reveal...

An approach for computing worst-case flutter margins has been formulated in a robust stability framework. Uncertainty operators are included with a linear model to describe modeling errors and flight variations. The structured singular value, μ , computes a stability margin that directly accounts for these uncertainties. This approach introduces a new method of computing flutter margins and an ...

OBJECTIVES We tested the hypothesis that the response to flecainide infusion can identify patients with atrial fibrillation (AF) in whom the hybrid pharmacologic and ablation therapy reduces the recurrences of AF. BACKGROUND Infusion of class IC anti-arrhythmic drugs may promote transformation of AF into atrial flutter. Catheter ablation of atrial flutter has been demonstrated to be highly ef...

OBJECTIVES Our purpose was to assess the risk factors for late mortality, loss of sinus rhythm and atrial flutter after the Mustard operation. BACKGROUND The Mustard operation provides correction of cyanosis with low surgical risk in transposition of the great vessels. However, right ventricular failure, loss of sinus rhythm, atrial flutter and death are frequent long-term complications. ME...

OBJECTIVES This study was designed to elucidate the location and mechanism of typical atrial flutter in the transplanted heart. BACKGROUND Although the F wave morphology in atrial flutter is similar in nontransplanted and transplanted hearts, the surgical incision needed for the atrial anastomosis may create a distinct electrophysiologic substrate of atrial flutter. METHODS Entrainment from...

Background-We studied atrial activation during induced atrial flutter in the canine sterile pericarditis model to test the hypothesis that the atrial flutter reentrant circuit includes a septal component. Methods and Results-We studied 10 episodes of induced, sustained (>5 minutes) atrial flutter in 9 dogs. In all episodes, the reentrant circuit included a septal component. In 6 episodes, there...

The aim of this study was an analysis of the time required to swim to a victim and tow them back to shore, while perfoming the flutter-kick and the dolphin-kick using fins. It has been hypothesized that using fins while using the dolphin-kick when swimming leads to reduced rescue time. Sixteen lifeguards took part in the study. The main tasks performed by them, were to approach and tow (double ...

Structural instability caused by self exciting aerodynamic forces (flutter) can be used as an effective input source for small scale energy harvesters. The self exciting aerodynamic force exerted on a T-shape cantilever causes periodic vibration, which can be converted into electric power through an electromagnetic transducer. Due to the complexities inherent in the fluid-structure interaction ...

Flutter is an unstable oscillation caused by the interaction of aerodynamics and structural dynamics. It can lead to catastrophic failure and therefore must be strictly avoided. Weight reduction and aerodynamically efficient high aspect ratio wing design reduce structural stiffness and thus reduce flutter speed. Consequently, the use of active control systems to counter these adverse aeroservoe...

Ablation of cavotricuspid ishtmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both c...