The sodium concentration gradient in the kidney (from the cortex to the medulla) serves to regulate fluid homeostasis and is tightly coupled to renal function. It was previously shown that renal function and pathophysiology can be characterized in rat kidneys by measuring the sodium gradient with 23 Na MRI. This study demonstrates for the first time the ability of 23 Na MRI to map the distribution of sodium in the human kidney and to quantify the corticomedullary sodium gradient. The study was performed on a 3T Signa LX scanner (GE) using an in-house-built quadrature surface coil.
Considerations related to the design of the Halton Landfill as a "hydraulic trap" are summarized together with the research that was conducted to support the design concept. The interrelationship between hydrogeology and the engineered design is examined. Laboratory experiments demonstrated that there can be diffusion away from a source, even with significant inward velocity. Existing theory was found to provide a good prediction of the observed concentration profile in these experiments. It is also shown that a pressurized air pocket below the clay effectively acts as a zero-flux boundary and hence, with respect to migration of chloride, could be conservatively neglected in the impact assessment. The results of the impact calculations predict only a small increase in chloride concentration in the receptor aquifer while there is negligible predicted impact due to organic contaminants. The landfill was designed and constructed with a granular "sub-liner contingency layer" (SLCL) beneath the compacted liner. The operation of this layer is discussed. Finally, the construction of the compacted clayey liner with a hydraulic conductivity of 1 × 10-8 cm/s is documented.Key words: landfill, hydraulic containment, liner, field case, construction.
Twenty years ago I wouldn't have advised my worst enemy to take the Vice-Presidency. It was God's way of punishing bad campaigners, a sort of political purgatory for the also-rans. Now you'd be crazy not to take the job. Aide to President Ronald Reagan 2 Many a true word is spoken in jest, we're told. More surprisingly, sometimes the truth even emerges, unsought, from the mouths of politicians and their flacks. This may be the case with regard to recent claims by Vice President Dick Cheney's office that he is, properly speaking, a "legislative officer" rather than a member of the executive branch. 3 The consequences of this argument, however, may prove unpalatable to the Bush Administration on closer examination. Indeed, an activist Vice Presidency, in the Cheney model, might be considered unconstitutional if the Vice President is regarded as a legislative official. And, regardless of whether that characterization controls, there may be prudential reasons for keeping the Vice President at a greater remove from executive affairs than has recently been the case. The Cheney-as-legislator kerfuffle appeared as part of an interbranch struggle over the declassification of documents. Rep. Henry Waxman argued that Cheney was avoiding legally required scrutiny by the National Archives and Records Administration, while Cheney's office argued that
http://www.instapundit.com. Thanks to Matt Lindsay for research assistance. 1. ERIC HOFFER, THE ORDEAL OF CHANGE 109 (1963). 2. At the time of this writing, Technorati.com reports that it's indexing 34.2 million weblogs and 2.3 billion links. Technorati Weblog, http://technorati.com (last visited Apr. 12, 2006).
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