The performance of a direct-sequence spread-spectrum acquisition system using a linear prediction filter for narrowband interference suppression

The coarse acquisition performance of a direct sequence spread-spectrum receiver is analyzed when a linear prediction filter is used for narrowband interference suppression. We show that once an appropriate matching strategy is identified, the linear prediction filter can provide favorable performance when narrowband interference is present over a considerable range of both interference power and bandwidth. In addition, the presence of the filter dramatically improves the performance over the case where there is no filter, except when the interference bandwidth and the power are both small (i.e., when the processing gain provides sufficient interference immunity without the filter). If long spreading sequences are used with moderately sized observation windows, the acquisition performance can be severely degraded when a parallel acquisition scheme is used due to the linear predication filter. We show, however, that a slower serial receiver will provide reliable performance.This work was supported in part by the Office of Naval Research under contract ONR N00014-91-J-1234, the Army Research Office under contract ARO DAAL03-91-0071, and the NSF Center for Ultra-High Speed Circuits and Systems (ICAS).     

Modeling of optical low coherence reflectometry recorded Braggreflectograms: evidence to a decisive role of Bragg spectral selectivity

This paper draws attention to the basic principles governing reflections in uniform Bragg reflectors (BR) when measured employing optical low coherence reflectometry (OLCR) technique. Using computations based on transfer matrix method (TMM), we first showed a strong spectral dependence of Bragg reflectograms on an OLCR probe spectrum. Later, this dependence is exploited to evaluate, for the first time, the coupling coefficient κ of a Bragg grating in a distributed Bragg reflector (DBR) laser on InP     

Rectal sexual trauma including foreign bodies

We used a potent and specific monoclonal antibody to somatostatin to test the physiologic inhibitory role of the tetradecapeptide somatostatin on pancreatic secretion. Somatostatin immunoneutralization increased both the total amylase and volume of pancreatic secretion. Cholecystokinin-A receptor antagonism abolished the stimulatory effect of somatostatin immunoneutralization. We conclude that somatostatin tonically inhibits, pancreatic secretion in fasted rats via inhibition of the release or action of cholecystokinin. Furthermore, the source of these peptides is likely islet delta cells and intrapancreatic neurons, respectively.     

Kinematics of heelstrike during walking and carrying: implications for slip resistance testing

Slip resistance measurements of shoes and floors are used to evaluate the potential for slip and fall injuries. These measurements are believed to have increased validity when they more closely reflect actual heelstrike biomechanics during locomotion. The purpose of this study was to describe heelstrike kinematics during load carrying to provide data towards improved slip resistance testing. Foot kinematics during load carrying (unladen and carrying from 0 to 13.5 kg) at various cadences (70, 90, 100 steps/min) was recorded. Measures before, during and after heelstrike were analysed. Cadence was an important predictor for all variables measured, associated with changes from 13% to over 100%. The load carried was an important predictor for only the heel slip distance after heelstrike, but this effect needs to be investigated further. These results can be used to improve the fidelity of slip resistance measurements, which is critical to reduce slip and fall injuries in the workplace or during activities of daily living.     

Detection and localization of degradation damaged regions in 1.3 μm laser diodes on InP using low-coherence reflectometry

We report here on the high potential of low-coherence reflectometry, a basically nondestructive technique, to detect and to localize spatially the degradation damaged regions in 1.3 μm laser diodes on InP. Using 1.3 μm low-coherence probe, three Fabry–Perot lasers with identical active regions (compressively strained multi-quantum wells) and exhibiting different degradation behaviors are investigated. The degradation induced modifications in the optical and electrical activity of the laser cavities are monitored by recording reflectograms both with and without carrier injection. This methodology gave precise information to detect and spatially localize the damaged regions in the cavities of degraded lasers.     

Pure CuBi2O4 Photoelectrodes with Increased Stability by Rapid Thermal Processing of Bi2O3/CuO Grown by Pulsed Laser Deposition

A new method for enhancing the charge separation and photo‐electrochemical stability of CuBi₂O₄ photoelectrodes by sequentially depositing Bi₂O₃ and CuO layers on fluorine‐doped tin oxide substrates with pulsed laser deposition (PLD), followed by rapid thermal processing (RTP), resulting in phase‐pure, highly crystalline films after 10 min at 650 °C, is reported. Conventional furnace annealing of similar films for 72 h at 500 °C do not result in phase‐pure CuBi₂O₄. The combined PLD and RTP approach allow excellent control of the Bi:Cu stoichiometry and results in photoelectrodes with superior electronic properties compared to photoelectrodes fabricated through spray pyrolysis. The low photocurrents of the CuBi₂O₄ photocathodes fabricated through PLD/RTP in this study are primarily attributed to their low specific surface area, lack of CuO impurities, and limited, slow charge transport in the undoped films. Bare (without protection layers) CuBi₂O₄ photoelectrodes made with PLD/RTP shows a photocurrent decrease of only 26% after 5 h, which represents the highest stability reported to date for this material. The PLD/RTP fabrication approach offers new possibilities of fabricating complex metal oxides photoelectrodes with a high degree of crystallinity and good electronic properties at higher temperatures than the thermal stability of glass‐based transparent conductive substrates would allow.     

Structural analysis of substrate binding by the molecular chaperone DnaK

DnaK and other members of the 70-kilodalton heat-shock protein (hsp70) family promote protein folding, interaction, and translocation, both constitutively and in response to stress, by binding to unfolded polypeptide segments. These proteins have two functional units: a substrate-binding portion binds the polypeptide, and an adenosine triphosphatase portion facilitates substrate exchange. The crystal structure of a peptide complex with the substrate-binding unit of DnaK has now been determined at 2.0 angstroms resolution. The structure consists of a beta-sandwich subdomain followed by alpha-helical segments. The peptide is bound to DnaK in an extended conformation through a channel defined by loops from the beta sandwich. An alpha-helical domain stabilizes the complex, but does not contact the peptide directly. This domain is rotated in the molecules of a second crystal lattice, which suggests a model of conformation-dependent substrate binding that features a latch mechanism for maintaining long lifetime complexes.     

The Edwards SD scale: A short form of the MMPI?

Edwards has described a rationale for predicting MMPI scores based upon social desirability response bias. The clinical utility of this technique was examined by comparing the predicted average MMPI profile with the average profile actually obtained by college males. The estimated and actual profiles were markedly discrepant, indicating that Edwards' SD scale is not a useful substitute for the MMPI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A novel design proposal to minimize reflections in deep-ridgemultimode interference couplers

We propose and demonstrate here the high efficiency of a novel design for deep-ridge multimode interference (MMI) couplers rendering them to behave like good transmitters with minimized reflections when integrated with emission devices. Using optical low-coherence reflectometry measurements, this novel design is shown to suppress to a great extent the highly detrimental internal resonance and often important backreflections inherent to even fully optimized deep-ridge MMIs