The calculation of slope (downhill gradient) for a point in a digital elevation model (DEM) is a common procedure in the hydrological, environmental and remote sensing sciences. The most commonly used slope calculation algorithms employed on DEM topography data make use of a three-by-three search window or kernel centered on the grid point (grid cell) in question in order to calculate the slope...

One of the most widely available procedures packaged with CIS for the analysis of a Digital Elevation Model (DEM) is the identification of the viewable area, or the viewshed. The elevations recorded in the DEM do, however, contain error, and the USGS, for example, publishes a Root Mean Squared Error (RMSE) for each DEM. Research reported here assesses the uncertainty of locations being within a...

A terrain-aided navigation method for an underwater glider is proposed that is suitable for use in ice-covered regions or areas with heavy ship traffic where the glider may not be able to surface for GPS location updates. The algorithm is based on a jittered bootstrap algorithm, which is a type of particle filter that makes use of the vehicle’s dead-reckoned navigation solution, onboard altimet...

Bedforms are irregular features that cannot easily be described by mean values. The variations in the geometric dimensions affect the bed roughness, and they are important in the modeling of vertical sorting and in modeling the thickness of cross-strata sets. The authors analyze the variability of bedform dimensions for three sets of flume experiments, considering PDFs of bedform height, trough...

The objective of this study was to characterize the temporal and altitudinal variation in microclimate of high elevation spruce–fir (Picea rubens–Abies balsamea) forests in three major mountain ranges of the northeastern United States. Mean lapse rates of air temperature were comparable to those previously reported for this region, but lapse rates varied considerably in relation to diurnal (and...

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transcatheter mitral valve implantation (TMVI) has emerged as an alternative to surgery in high risk patients with failing bioprosthesis (valve-in-valve) or annuloplasties (valve-in-ring). The presence elevated mean gradient > 5mmHg after the procedure been defined unsuccessful but impact and outcomes TMVI have...

BACKGROUND The anti-elevation syndrome is an adverse outcome of anterior transposition of the inferior oblique muscle. The presumed cause is an excessive anti-elevating force vector that occurs with attempted elevation in abduction. This causes apparent overaction of the contralateral inferior oblique muscle due to fixation duress. It has been suggested that excessive residual extorsion may hel...