Wide-band symmetrical analog multiplier IC for coherentoptical-fiber receivers operating up to 10 Gb/s

A versatile analog four-quadrant multiplier IC with large bandwidth (DC to 6 GHz and 10 Gb/s) and large dynamic range is presented. It was mainly developed for differential-phase-shift-keying (DPSK) phase demodulator and polarization diversity receivers in coherent optical-fiber transmission systems. The circuit consumes 450 mW and only needs a single power supply of -5 V. The circuit principle used allows exact symmetry with respect to both linear inputs, which reduced multiplication errors. In the intended application, especially, the time jitter and the offset voltage of the output pulse patterns are reduced to negligible values. The IC was realized in a 1.25-μm double-polysilicon bipolar technology     

Homogenization of hardness distribution and distortion in high pressure gas quenching

Quenching with gases rather than oil or other liquid media has the advantages of reducing the risks concerning health and environment, while simultaneously homogenizing the quenching results and minimizing distortion due to a wide range of possible process parameter variations and the pure convective heat transfer. In this contribution, a coupled solution for increasing homogenization of quenching results within high pressure gas quenching will be presented. In the first stage, an experimental test facility was set up for flow investigations and in the second stage a numerical simulation model was generated. The numerical and experimental results of the flow through the chamber were compared for several boundary conditions. Finally, after complete verification of the simulation, the model may be used to assist in parameter variation for optimization of homogeneous high pressure gas quenching.     

The modulatory cholinergic system in goldfish tectum may be necessary for retinotopic sharpening

The cholinergic circuit within the tectum and the cholinergic input from the nucleus isthmi mediate a presynaptic augmentation of retinotectal transmitter release via nicotinic receptors. In this study, the cholinergic systems were either eliminated using the cholinergic neurotoxin AF64A or blocked using nicotinic antagonists to test for effects on the activity-driven sharpening of the regenerating retinotectal projection. The effectiveness of the AF64A was verified by recording field potentials elicited by optic tract stimulation and by immunohistochemical staining for choline acetyltransferase (ChAT). At 1 week after intracranial (IC) injection of AF64A (12 to 144 nmoles) into the fluid above the tectum, field potentials showed a selective dose-dependent decrement of the cholinergic polysynaptic component with no effect on the amplitude of the glutamatergic monosynaptic component. The decrement was only partially recovered in recordings at 2 and 6 weeks. In normal fish, the ChAT antibody stains a population of periventricular neurons, their apical dendrites, and a dense plexus within the optic terminal lamina that consists of their local axons and fine dendrites and of input fibers from the nucleus isthmi. One week after IC AF64A injection (48-72 nmoles), most immunostaining in superficial tectum was lost but most neuronal somas in the deep tectum could still be seen, and staining in the tegmentum below the tectum was completely intact. At 2 weeks and later, the staining of neuronal somata largely recovered, but staining of the superficial plexus did not. AF64A treatment at 18 days after nerve crush, when regenerating retinal fibers are beginning to form synapses, prevented retinotopic sharpening of the projection. Recordings showed a rough retinotopic map on the tectum but the multiunit receptive fields (MURFs) at each tectal point averaged 34 deg vs. 11 deg in vehicle-injected control regenerates. AF64A treatment before nerve crush also blocked sharpening, ruling out a direct effect on retinal growth cones or retinal fibers, as AF64A rapidly decomposes, whereas its effect on the cholinergic fibers is long-lasting. IC injection or minipump infusion of the nicotine antagonists alpha-bungarotoxin (alpha BTX), neuronal bungarotoxin (nBTX), and pancuronium during regeneration also prevented sharpening (MURFs averaging 29.4 deg, 33.0 deg, and 31.4 deg, respectively). Control Ringer's solution infusions or injections over the same period (19-37 days postcrush) had no effect on regenerated MURF size (11.7 deg). The results show that the cholinergic innervation, which modulates transmitter release, is required for activity-driven retinotopic sharpening, thought to be triggered by NMDA receptor activation.     

One-step synthesis of functional Co nanoparticles for surface-initiated polymerization

Much effort is conducted to construct artificial objects that are capable of converting chemical or electromagnetic energy into a specific, predetermined motion on the nanoscale. We present results on the synthesis of core–shell nanoparticles capable to be set in rotation by the application of electromagnetic fields. The nanorotors implied in the study are based on the cobalt nanospheres decorated with a stabilizing brush shell composed of poly(?-caprolactone) that is attached by surface-initiated polymerization. The functional cores used as macroinitiators can be fabricated alternatively by a two-step or a one-step process.     

Laboratory simulated slipstream testing of novel sulfur removal processes for gasification application

The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project is investigating an Early Entrance Coproduction Plant (EECP) concept to evaluate integrated electrical power generation and methanol production from coal and other carbonaceous feedstocks. Research, development and testing (RD&T) that is currently being conducted under the project is evaluating cost effective process systems for removing contaminants, particularly sulfur species, from the generated gas which contains mainly synthesis gas (syngas), CO₂ and steam at concentrations acceptable for the methanol synthesis catalyst. The RD&T includes laboratory testing followed by bench-scale and field testing at the SG Solutions Gasification Plant located in West Terre Haute, Indiana. Actual synthesis gas produced by the plant was utilized at system pressure and temperature for bench-scale field testing.     

Effects of combined nimodipine and metrifonate on rat cognition and cortical EEG

The present study investigated if short-term treatment with an L-type Ca2+-channel inhibitor, nimodipine, can stimulate cognitive functioning and cortical electroencephalograph (EEG) arousal, and potentiate the effect of a cholinesterase inhibitor, metrifonate. Pretraining administration of nimodipine (3, 10 and 30 mg/kg, p.o.) had no effect on water maze and passive avoidance behavior of young neurologically intact controls, or water maze and passive avoidance performance failure induced by scopolamine pretreatment (i.p.; 0.4 mg/kg during the water maze and 2.0 mg/kg during the passive avoidance study), medial septal lesioning, or aging. Furthermore, nimodipine (3, 10 and 30 mg/kg, p.o.) had no effect on the improvement by metrifonate (10 mg/kg, p.o.) of the water maze and passive avoidance failure induced by scopolamine pretreatment or medial septal lesioning, nor did it affect the potential of metrifonate (30 mg/kg. p.o.) to improve the water maze or passive avoidance behavior of aged rats. Finally, nimodipine (3, 10 and 30 mg/kg, p.o.) had no effect on spontaneously occurring thalamically generated neocortical high-voltage spindles or spectral EEG activity of young controls, nor did it alleviate the spectral EEG abnormality induced by scopolamine (0.2 mg/kg, i.p.) administration. Also, the combination of nimodipine 3 or 10 mg/kg and a subthreshold dose of metrifonate 10 mg/kg could not suppress high-voltage spindles or scopolamine treatment-induced spectral EEG activity abnormalities. According to the present results, short-term treatment with nimodipine does not stimulate cognitive functions or increase cortical EEG arousal, and does not block or potentiate the propensity of metrifonate to improve cognitive performance of rats.     

Comprehensive meta-analysis of integrity test validities: Findings and implications for personnel selection and theories of job performance.

Conducted a comprehensive meta-analysis based on 665 validity coefficients across 576,460 data points to investigate whether integrity test validities are generalizable and to estimate differences in validity due to potential moderating influences. Results indicate that integrity test validities are substantial for predicting job performance and counterproductive behaviors on the job, such as theft, disciplinary problems, and absenteeism. The estimated mean operational predictive validity of integrity test for predicting supervisory ratings of job performance is .41. Results from predictive validity studies conducted on applicants and using external criterion measures (i.e., excluding self-reports) indicate that integrity tests predict the broad criterion of organizationally disruptive behaviors better than they predict employee theft alone. Despite the influence of moderators, integrity test validities are positive across situations and settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reproducibility and validity of an extensive semiquantitative food frequency questionnaire among Greek school teachers

The involvement of mental health professionals in determinations of dangerousness is both common and controversial. Among the various contexts for these evaluations, the release of potentially violent forensic patients from maximum security facilities evokes justified concern from involved experts and apprehension to outrage from the immediate community. We sought to examine how conclusions are reached on dangerousness at two sequential stages: clinical recommendations and Manifest Dangerousness Hearings decisions. In an archival study of 245 patients, we found that lack of progress in the institution and physical assaultiveness were the strongest correlates with dangerousness. In contrast, experts and review boards appeared to be relatively less influenced by diagnosis, types of treatment, and sociodemographic variables.