“Space drives,” “Warp drives,” and “Wormholes:” these concepts may sound like science fiction, but they are being written about in reputable journals. To assess the implications of these emerging prospects for future spaceflight, NASA supported the Breakthrough Propulsion Physics Project from 1996 through 2002. This project has three grand challenges: (1) Discover propulsion that eliminates the...

Treatment of chronic non-cancer pain with opioid therapy has escalated in recent years, resulting in exploding therapeutic use and misuse of prescription opioids and multiple adverse drug events. Breakthrough pain is defined as a transient exacerbation of pain experienced by individuals who have relatively stable and adequately controlled baseline cancer pain. Further, the definition of breakth...

[1] Investigations of solute transport in fractured rock aquifers often rely on tracer test data acquired at a limited number of observation points. Such data do not, by themselves, allow detailed assessments of the spreading of the injected tracer plume. To better understand the transport behavior in a granitic aquifer, we combine tracer test data with single-hole ground-penetrating radar (GPR...

A laboratory-scale tracer test has been carried out to improve the characterization of the transport properties of the concrete from the Radioactive Waste Disposal Facility at El Cabril (Spain). High entry pressure was employed in order to perform the experiment in a reasonable time span. Lithium, bromide and deuterium were used as tracers. The conceptual model considered matrix diffusion betwe...

[1] Tracer buoyancy has been shown to influence breakthrough from two-well tracer experiments conducted in porous media. Two-well tracer experiments are presented from fractured crystalline bedrock, in which the specific gravity of the tracer injectate varied from 1.0002 to 1.0133. Under the forced hydraulic conditions imposed, no difference in breakthrough was noted for the three experiments. ...

The reduction of Cr(VI) by use of a cheap and locally available industrial waste, scrap iron, was investigated in continuous system. The experimental results showed that, at the beginning of the column experiment, Cr(VI) was not detected in column effluent, which means that it was completely reduced. The greater the pH of column influent, the lower the time period before the breakthrough of hex...

BACKGROUND The precision and limitations of ventricular pacemapping as a method to localize the site of earliest breakthrough of ventricular tachycardia (VT) were investigated in a canine model of experimental myocardial infarction. METHODS AND RESULTS Forty-one episodes of VT induced in 10 animals were mapped using a standard grid of 64 endocardial and epicardial bipolar electrodes to determ...