OBJECTIVE To evaluate whether the shape of the airway pressure-time (Paw-t) curve during constant flow inflation corresponds to radiologic evidence of tidal recruitment or tidal hyperinflation in an experimental model of acute lung injury. DESIGN Prospective randomized laboratory animal investigation. SETTING Department of Clinical Physiology, University of Uppsala, Sweden. SUBJECTS Anest...

An index obtained from tidal expiration, the ratio of time to peak tidal expiratory flow (tPTEF) to expiratory time (tE), discriminates between groups with and without airflow obstruction in infants and children and correlates with other measurements of airflow obstruction in adults. The aim of this study was to determine whether the diagnosis of airflow obstruction could be made from an analys...

[1] A simplified model for tidal flow in a basin is presented. The model is based on the assumption of a flat water surface oscillating synchronously in the tidal basin. Under this hypothesis the depth-averaged continuity equation becomes a Poisson equation that can be easily resolved at each instant of the tidal cycle. This formulation, which is particularly valid for small, deep basins, provi...

Groundwater plays an important role in coastal regions by delivering freshwater and nutrients to near shore and salt marsh environments. To quantify groundwater flow, salinity, temperature and pressure, sensors were installed in shallow piezometers along a transect behind Blackbeard Island, GA. Located approximately 90 m from the nearest tidal creek, the transect reaches from a back barrier isl...

Negative expiratory pressure (NEP) applied at the mouth during tidal expiration provides a non-invasive method for detecting expiratory flow limitation. Forty-two children were studied, i.e. 25 children with different respiratory symptoms (R) and 17 without any respiratory symptoms (NR). Children were examined without any sedation. A preset NEP of -5 cm H(2)O was applied; its duration did not e...

A tidal bore is a surge of water propagating upstream as the tidal flow turns to rising into an estuary with a tidal range larger than 5 to 6 m and a bathymetry that amplifies the tidal wave. The bore front is a shock characterised by a singularity of the free-surface and pressure and velocity fields. This study aims to characterise the tidal bore propagation and the induced turbulent mixing un...

An analysis of current profiles carried out on moored Acoustic Doppler Current Profiler data sets recorded during the Variability of Exchanges In the Northern Seas project is presented here for several locations in three sections in the vicinity of the Iceland-Scotland Ridge: (1) north of the Faroes, (2) in the Faroe-Bank Channel and (3) in the Faroe-Shetland Channel. Total currents have been d...

[1] The tidal flow field in a basin of small dimensions with respect to the tidal wavelength is calculated. Under these conditions, the tide becomes a standing wave oscillating synchronously (with a flat water surface) over the whole basin. The shallow water equations can thus be strongly simplified, expressing the discharge vector field in terms of a potential function and a stream function. T...

variability of tidal volume and respiratory rate in normally breathing man has long been demonstrated [1]. however because of lack of knowledge and technology primary ventilators could only deliver a fixed tidal volume in a fixed rate the so called volume controlled ventilation (vcv). vcv was volume preset time triggered and cycled and there was no synchronization with patient’s breaths. at tha...

[1] During March–April 1999, 2 weeks of undulating CTD and shipboard acoustic Doppler current profiler surveys revealed the variability of the intense internal tide on the northern edge of Georges Bank. The nature of the internal tide was modulated by episodic surface intrusions of cool, fresh Scotian Shelf Water (SSW), stratifying the otherwise vertically well-mixed outer bank. The introductio...