Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Particularly useful are the n=0, or axisymmetric, modes in which there is no displacement (or pressure) variation over the pipe cross section. Previous work has focused on tw...

We experimentally studied the propagation of coupled fluid stress waves and tube flexural waves generated through projectile impact along the axis of a water-filled tube. We tested mild steel tubes, 38–40 mm inner diameter and wall thicknesses of 0.8 mm, 6.4 mm, and 12.7 mm. A steel impactor was accelerated using an air cannon and struck a polycarbonate buffer placed on top of the water surface...

Objective: The urethra generates myogenic tone during bladder filling to maintain continence. There are few visual studies of urethra motor activity and the specific Ca signalling of urethral smooth muscle is relatively unknown. In the present study, we sought to characterize the pattern of smooth muscle cell activation in urethra utilizing Ca imaging with a genetically encoded Ca reporter, GCa...

This paper is concerned with the real-time observation system of optical devices for recording of sea waves characteristics in wide range of wavelength from centimeters to hundreds meter. The energy spectra of short waves are obtained in real time by spectral analysis of sea surface image [1] with spectral analyzer operating under no coherent light. The spectral-kinematics characteristics of lo...

BACKGROUND Over a time course of months, the stability of atrial fibrillation (AF) gradually increases and the efficacy of pharmacological cardioversion declines both in humans and in animal models. Changes in fibrillatory conduction over this period largely are unexplored. METHODS AND RESULT Goats were instrumented with an atrial endocardial pacemaker lead and a burst pacemaker. AF was maint...

We find a linear instability of non-axisymmetric Rossby waves in a thin nonmagnetized Keplerian disk when there is a local maximum in the radial profile of a key function L(r) ≡ F(r)S2/Γ(r), where F−1 = ẑ · (∇× v)/Σ is the potential vorticity, S = P/ΣΓ is the entropy, Σ is the surface mass density, P is the vertically integrated pressure, and Γ is the adiabatic index. We consider in detail the ...

EIT waves” are large-scale coronal bright fronts (CBFs) that were first observed in 195 Å images obtained using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). Commonly called “EIT waves”, CBFs typically appear as diffuse fronts that propagate pseudo-radially across the solar disk at velocities of 100–700 km s−1 with front widths of 50–100 ...

Near field coseismic perturbations of ionospheric total electron content (TEC), caused by direct acoustic waves from focal regions, can be observed with Global Positioning System (GPS). They appear 10-15 minutes after the earthquake with typical periods of ~4-5 minutes, and propagate as fast as ~1 km/s toward directions allowed by ambient geomagnetic fields. Ionospheric disturbance, associated ...

We treated Limulus ventral photoreceptors with the phosphatase inhibitors fluoride, vanadate, and GTP-gamma-S [guanosine-5'0-(3-thiotriphosphate)] under various conditions of illumination and external calcium concentrations. In the dark in low-calcium (1 mM) artificial seawater (ASW), fluoride-induced discrete waves cluster together in time. Under these conditions, the intervals between waves w...

Ocean waters often show layered structures especially where exchange flow between two basins occurs. These structures are often attributed to processes such as double.diffusive convection, internal waves, turbulent modulated mixing. In this paper by examining the vertical structures of temperature, salinity and density, of the middle parts of Caspian Sea it is shown that such layered structure ...