Genetically engineered pfabA pfabR bacteria: an electrochemical whole cell biosensor for detection of water toxicity

We describe here a bacterial sensor for electrochemical detection of toxic chemicals. The sensor constitutes recombinant bacteria harboring plasmids encoding the fabA and fabR genes and has high-resolution amperometric response to membrane-damaging chemicals. For example, it can detect phenol at concentrations ranging between 1.6 and 16 ppm within 20 min. The high sensitivity is achieved by using the fabA promoter fused to a reporter gene-encoded beta-galactosidase on a low copy number plasmid, under the control of the FabR repressor. The use of electrochemical whole cell sensors enables sensitive, fast, easy to operate, and cost-effective detection of water toxicity threats.     

Nanoparticle PEBBLE sensors for quantitative nanomolar imaging of intracellular free calcium ions

Ca(2+) is a universal second messenger and plays a major role in intracellular signaling, metabolism, and a wide range of cellular processes. To date, one of the most successful approaches for intracellular Ca(2+) measurement involves the introduction of optically sensitive Ca(2+) indicators into living cells, combined with digital imaging microscopy. However, the use of free Ca(2+) indicators for intracellular sensing and imaging has several limitations, such as nonratiometric measurement for the most-sensitive indicators, cytotoxicity of the indicators, interference from nonspecific binding caused by cellular biomacromolecules, challenging calibration, and unwanted sequestration of the indicator molecules. These problems are minimized when the Ca(2+) indicators are encapsulated inside porous and inert polyacrylamide nanoparticles. We present PEBBLE nanosensors encapsulated with rhodamine-based Ca(2+) fluorescence indicators. The rhod-2-containing PEBBLEs presented here show a stable sensing range at near-neutral pH (pH 6-9). Because of the protection of the PEBBLE matrix, the interference of protein-nonspecific binding to the indicator is minimal. The rhod-2 PEBBLEs give a nanomolar dynamic sensing range for both in-solution (K(d) = 478 nM) and intracellular (K(d) = 293 nM) measurements. These nanosensors are useful quantitative tools for the measurement and imaging of the cytosolic nanomolar free Ca(2+) levels.     

Agenda Building, Agenda Setting, Priming, Individual Voting Intentions, and the Aggregate Results: An Analysis of Four Israeli Elections

This article reports the findings of the multistage agenda-setting process of four Israeli elections. In the first stage, agenda building, it is demonstrated that there is a close association between real-world indicators and media agenda. In the second stage, agenda setting, it was found that the level of television coverage of issues influences the proportion of surveys' respondents naming these issues as the nation's most important problems. In the third stage, priming, the analysis focused on electoral voting behavior in multiparty parliamentary elections rather than on the usual evaluations of the president's performance. At the individual level, there is evidence for a priming effect. At the aggregate level, the findings suggest that there may be a priming effect on the actual electoral success of various political parties.     

A contingency model for estimating success of strategic information systems planning

Strategic information system planning (SISP) has been identified as a critical management issue. It is considered by many as the best mechanism for assuring that IT activities are congruent with those of the rest of the organization and its evolving needs.     

Multiwavelet Frames in Signal Space Originated From Hermite Splines

We present a method for construction of multiwavelet frames for manipulation of discrete signals. The frames are generated by three-channel perfect reconstruction oversampled multifilter banks. The design of the multifilter bankstarts from a pair of interpolatory multifilters. We derive these interpolatory multifilters from the cubic Hermite splines. We use the original preprocessing algorithms, which transform scalar signals into vector arrays that serve as inputs to the oversampled analysis multifilter banks. These preprocessing algorithms do not degrade the approximation accuracy of the transforms of the vectors by multifilter banks. The postprocessing algorithms convert the vector output of the synthesis multifilter banks into scalar signal. The discrete framelets, generated by the designed filter banks, are symmetric and have short support. The analysis framelets have four vanishing moments, whereas the synthesis framelets converge to Hermite splines supported on the interval [-1,1]     

Scalable distributed on-the-fly symbolic model checking

This paper presents a scalable method for parallel symbolic on-the-fly model checking in a distributed memory environment. Our method combines a scheme for on-the-fly model checking for safety properties with a scheme for scalable reachability analysis. We suggest an efficient, BDD-based algorithm for a distributed construction of a counterexample. The extra memory requirement for counterexample generation is evenly distributed among the processes by a memory balancing procedure. At no point during computation does the memory of a single process contain all the data. This enhances scalability. Collaboration between the parallel processes during counterexample generation reduces memory utilization for the backward step. We implemented our method on a standard, loosely- connected environment of workstations, using a high-performance model checker. Our initial performance evaluation, carried out on several large circuits, shows that our method can check models that are too large to fit in the memory of a single node. Our on-the-fly approach may find counterexamples even when the model is too large to fit in the memory of the parallel system.     

Drying in a new two impinging streams reactor

A new gas-solid reactor, employing two impinging streams with oscillatory motion of the solid particles, was developed and successfully tested in evaporation experiments. Comparisons of the performance of the reactor with other commonly used devices, namely, spray dryer, spouted bed, stream dryer and a fluidized bed, indicated a most high efficiency in carrying out drying of moistened particles by a hot stream of gas. In addition, the pumping work per kg of solids transported by air through the reactor is considerably lower in comparison to a fluidized bed.     

Deadlock-free connection-based adaptive routing with dynamic virtual circuits

Virtual circuits (VCs) can reduce routing overheads with irregular topologies and provide support for a mix of quality of service (QoS) requirements. Information about network loads and traffic patterns may be used during circuit establishment to utilize network resources more efficiently than is practical with packet routing. Most VC schemes are static—each established VC remains unchanged until the connection is no longer needed. In contrast, we propose the dynamic virtual circuit (DVC) mechanism, which enables existing circuits to be quickly torn down in order to free up resources needed for other circuits or to re-establish circuits along routes that are better suited for current network conditions. We propose a deadlock avoidance technique, based on unconstrained routing of DVCs combined with a deadlock-free virtual network. We present a correctness proof for the scheme, describe key aspects of its implementation, and present performance evaluation results that explore its potential benefits.