A great deal of research has investigated the potential parameters of tactile feedback for virtual buttons. However, these studies do not take the possible effects of feedback latencies into account. Therefore, this research investigates the impact of tactile feedback delays on touchscreen keyboard usage. The first experiment investigated four tactile feedback delay conditions during a number e...

This paper explores the potentially powerful role e-assessment practices can have on culture change in learning and teaching. This paper demonstrates how new e-assessment practices can ‘push back’ through educational institutions. This is done by applying the work of Gibbs and Simpson (2004/5) to e-assessment practices. To illustrate the practical effects of this evidence-based framework, the a...

Bioprosthetic valve calcification is usually assessed pathologically by gross inspection, radiographic studies, and histologic examination. Quantitation of mineral content by chemical assay has not been reported for failed clinical valves removed from adults. In this study, calcium determination by atomic absorption spectroscopy was done on 52 removed porcine valves after routine pathologic exa...

A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves can be employed for implementing a complete immunoassay. Detection or biosensor chambers are either coated for immuno-interaction or a biosensor chip is inserted in them. On microfluidic CDs featuring such multi-step chemical/biological processes, the biosensor chamber must be repeatedly filled wit...

introduction : this in vitro study was designed to evaluate the effect of smear layer removal on push-out bond strength of white mineral trioxide aggregate (wmta) and calcium-enriched mixture cement (cem). materials and methods: dentin discs with 3 mm thicknesses were divided into 4 groups ( n =15): group 1: irrigation of the canal with normal saline and filling with wmta; group 2: irrigation w...

this article analyses the push and pull factors that bring visitors to the iranian national parks. the study used a structured questionnaire to collect data on these factors and the socio-demographic profile of the visitors. survey conducted in boujagh national park, an area of 3177 hectares located in the north of the iran, produced 400 questionnaires. the factor analysis identified four push ...

1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coag...

In an investigation of the influence of glutaraldehyde fixation pressure and subsequent valve constraint on the coaptive characteristics of porcine aortic valves, 14 valves were examined, eight having been fixed at low pressure (congruent to 1 mm Hg) and six at high pressure (80 mm Hg). The coaptive ratios of the left and right coronary leaflets in the low-pressure-fixed valves showed a signifi...

We studied the function of right internal jugular vein valves during cardiac catheterization in 32 patients and external jugular vein valves in vitro from 13 dogs. Patients with normal central venous pressure had competent valves during cough-induced transvalvular pressure gradients of 52.4 ± 8.6 mm Hg. Ten of 15 patients with elevated central venous pressure had either incompetent or absent in...