We have found experimentally that the shot noise of the tunneling current I through an undoped semiconductor superlattice is reduced with respect to the Poissonian noise value 2eI, and that the noise approaches 1/3 of that value in superlattices whose quantum wells are strongly coupled. On the other hand, when the coupling is weak or when a strong electric field is applied to the superlattice, ...

Pectin, an integral component of the plant cell wall, is a recalcitrant substrate against enzymatic challenges by most animals. In characterizing the source of a leaf beetle's (Cassida rubiginosa) pectin-degrading phenotype, we demonstrate its dependency on an extracellular bacterium housed in specialized organs connected to the foregut. Despite possessing the smallest genome (0.27 Mb) of any o...

Modern systems must be adaptable | to changing requirements, bugxes, new technologies and recon guration. For critical applications this must be possible at run-time; for complex applications it should be limitable to major sub-divisions of the system. The DRASTIC architecture addresses these goals by exploiting object persistence and distributed systems implementation techniques. It enables ru...

Rule finding is an important aspect of human reasoning and flexibility. Previous studies associated rule finding failure with past experience with the test stimuli and stable personality traits. We additionally show that rule finding performance is severely impaired by a mindset associated with applying an instructed rule. The mindset was established in Phase 1 (manipulation) of the experiment,...

Groundwater management and protection has been facilitated by computational modeling of aquifer vulnerability and monitoring aquifers using groundwater sampling. The DRASTIC (Depth to water, Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media, and hydraulic Conductivity) model, an overlay and index GIS model, has been used for groundwater quality assessment because it r...

The mechanisms wh(eeby, dietary sodium restriction leads to decreased arterial blood pressure is obscure. Previously reported studies of patients with arterial hypertension showed a lessened pressor response to norepinephrine after sodium restriction. In the present investigations, reduction in pressor response to norepinephrine during the low sodium period was observed only occasionally; sodiu...

More and more problems with groundwater come from the increasing industrialization and the growing waste problem. The DRASTIC model has been used as a valuable tool in many parts of the world for assessing the vulnerability of groundwater. In the DRASTIC system, however, factors that influence groundwater must be divided into ranges and then be given ratings according to whether or not their va...