Say that a surface in S ⊂ R has the central plane oval property, or cpo, if • S meets some affine plane transversally along an oval, and • Every such transverse plane oval on S has central symmetry. We show that a complete, connected C surface with cpo must either be a cylinder over a central oval, or else quadric. We apply this to deduce that a complete C surface containing a transverse plane ...

The issue of the influence of wall vibrations on the behavior of wind instruments is still under debate. The mechanisms of vibroacoustic couplings involved in these vibrations are difficult to investigate, as fluid-structure interactions are weak. Among these vibroacoustic interactions, the present study is focused on the coupling between the internal acoustic field and the mechanical behavior ...

We argue that closed string tachyons drive two spacetime topology changing transitions – loss of genus in a Riemann surface and separation of a Riemann surface into two components. The tachyons of interest are localized versions of Scherk-Schwarz winding string tachyons arising on Riemann surfaces in regions of moduli space where string-scale tubes develop. Spacetime and world-sheet renormaliza...

introduction: the purpose of this study was to evaluate the sealing ability of 3 obturation techniques in oval-shaped canals by bacterial leakage assessment. methods: sixty mandibular incisors with oval canals were selected after providing buccolingual and mesiodistal radiographs. the teeth were sectioned at a 10 mm distance from the apex. after instrumentation, the teeth were divided into 3 gr...

Congenital anomaly of the oval window with an abnormal facial nerve course is an uncommon embryological defect, which is related to the underdevelopment of second branchial arch derivatives. Some treatments for improving hearing levels are available; these include hearing aids, vestibulotomy, neo-oval window formation, and stapes surgeries, including incudostapedotomy and malleostapedotomy. How...

Growing evidence has shown that hepatic oval cells, also named liver progenitor cells, play an important role in the process of liver regeneration in various liver diseases. Oval cell proliferation has been reported in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) and chronic liver disease. Studies have found expression of HBV surface and core antigens in oval cells in the l...

The paper by A. Stotsky introduces an algorithm for real-time estimation of the engine friction torque, capable to achieve a dynamic adaptation of the static maps widely used in the engine control functionality. This adaptation of the friction map allows a better vehicle driveability performance and an enhanced control by the driver of the vehicle longitudinal transients. There are several inte...

Calculation of fin efficiency is necessary for the design heat exchangers. This can be calculated individual finned tubes or continuous fins. Continuous fins are mostly used in plate-fin and tube exchangers (PFTHEs). In most cases, basic elements those PFTHEs circular, oval flattened pipes, which contain circular polygonal fins, as observed PFTHEs, divided into virtual Those have a rectangular ...

A s is widely appreciated by all medical and surgical specialties, atrial fibrillation is the most common significant cardiac arrhythmia seen in practice; approximately 5 to 7 million patients in the United States have atrial fibrillation, with the numbers expected to increase to approximately 16 million by 2050 (1), and there are 200,000 to 250,000 new cases each year. Although symptoms vary w...