Saw-based chirp fourier transform and its application to analogue on-board signal processing

This paper reports on the work done at ELAB-RUNIT on surface acoustic wave (SAW) on-board signal processing. The main processing is done by the analogue chirp Fourier transformer (CFT) and its inverse (ICFT). In a CFT, the input signal is transformed from an FDMA format to a TDM format and at the same time filtered by a filter bank. By multiplying and convolving the signal with chirp waveforms, the CFT is implemented by one bandpass cover filter and one chirp filter. The paper demonstrates that SAW reflector array compressors (RAC) built by ELAB-RUNIT have suitable chirp responses and adequate precision for digital satellite communication. Two applications are described. An on-board multicarrier demodulator (MCD) for 9·6 kb/s QPSK carriers and a processor for filtering, routeing and beam steering (FROBE) for flexible transparent repeaters. For MCDs the use of SAW CFTs leads to a power consumption for demultiplexing and A/D conversion of 15 mW per carrier with room for improvements. For transparent paylods, the FROBE leads to more flexibility and narrower guardbands than can be obtained by other analogue processors.     

Priming and baseline perceptual identification performance in amnesia: A comment on Hamann, Squire, and Schacter.

There is evidence that stimulus processing deficits, some of which may be due to striatal damage, are prevalent in memory-impaired patients. The deficits often result in impaired baseline performance in implicit memory tasks, which in turn is associated with increased priming effects. When priming scores were corrected for such processing deficits, the authors found a relationship between priming and both recognition memory and mesial temporal lobe damage. On the basis of 4 tachistoscopic word identification experiments, S. B. Hamann et al (see record 1995-14158-001) challenged the notion that either processing deficits or striatal damage is prevalent in amnesia patients. They claim that both priming and baseline word identification are normal in amnesia patients, except that patients with Korsakoff amnesia show deficits under certain restricted circumstances. The authors argue that the results of the Hamann et al study are entirely consistent with their previous reports. When Hamann et al did not find differences between amnesia patients and controls in word identification, the results were contaminated by ceiling effects, and there was poor control over the effective exposure duration of the stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the linear complexity profile of nonlinear congruential pseudorandom number generators of higher orders

Nonlinear congruential methods are attractive alternatives to the classical linear congruential method for pseudorandom number generation. Generators of higher orders are of interest since they admit longer periods. We obtain lower bounds on the linear complexity profile of nonlinear pseudorandom number generators of higher orders. The results have applications in cryptography and in quasi-Monte Carlo methods.     

Electrodialytic removal of cadmium from straw combustion fly ash

Fly ash from straw combustion contains valuable nutrients when returned to agricultural soils. In many instances, however, this fly ash may contain heavy metals, such as cadmium, at levels which often exceed the limits given by the Danish legislation. Thus before utilizing the nutrients, cadmium must be removed from these ashes. The use of an electrodialytic remediation method to remove cadmium from fly ash arising from straw combustion and containing 11.2 mg Cd kg^?1 DM (dry matter) was accessed. After 36 days of remediation at a constant current density of 5.6 mA cm^?2 more than 97% of the cadmium had been removed from around 150 g ash on a dry basis. Copyright © 2004 Society of Chemical Industry     

The influence of blasting on grouted rockbolts

Field tests and laboratory investigations have been carried out to evaluate the performance of grouted rock bolts subjected to close proximity blasting. The investigations comprised pull-out testing of bolts and vibration measurements on both the rock and the bolts. Laboratory work comprised compressive and flexural testing of the grout and analysis of polished thin sections of specimens consisting bolt, grout and rock. There is no observable decrease in pull-out strength for bolts installed close to the blast (3.4 m), compared to more distant installed bolts (22.0 m). Furthermore, there is no difference in pull-out strength for the bolts with the freshest grout compared to bolts with cured grout, when subjected to blast loadings. Anchorage length of the bolts was 125 mm, which gave an average pull-out strength of 140 kN, or 93 % of steel yielding load. Analysis of polished thin sections of the rock, grout and bolt does not show any variation in crack pattern or crack frequency between bolts with varying distance to the blast or varying curing of the grout when subjected to the blast loadings. Re-pulling of previously pulled bolts shows a healing effect of the grout. None of the tests carried out indicates any decrease of the bolt /grout performance. It can be concluded that fully grouted bolts can be used on or close to the face.     

Theoretical and experimental evidence of different wettability classes

In this paper we analyze data from thirteen North Sea sandstone reservoirs that fall into the large group of intermediate wettability. By dividing this group into three sub-classes, fractionally-wet (FW), mixed-wet large (MWL) and mixed-wet small (MWS), we find an improved understanding of the intermediate-wet state. In the fractionally-wet state oil- and water-wet sites are random with respect to size, while in the mixed-wet state water- and oil-wet pores are sorted by size. We assume two classes of mixed wettability; MWL where the large pores are oil-wet and MWS where the small pores are oil-wet. The paper includes both theoretical considerations, pore–scale observations by ESEM, SEM and thin sections, as well as core scale wettability indices that indicate that these wettability states may exist in reservoirs.     

Word priming and recognition memory are both affected by mesial temporal lobe damage.

Amnesic patients with mesial temporal lobe pathology often produce normal priming effects despite severely impaired memory. This is generally interpreted to mean that whereas limbic structures are involved in conscious memory, other structures, comprising a separate memory system, mediate priming effects. Priming and recognition memory measures were correlated with magnetic resonance imaging (MRI) measures of damage to specific brain structures in a sample of 30 Ss. The results provide evidence that both priming and recognition memory may be adversely affected by mesial temporal lobe damage. Furthermore, the results suggest that striatal damage is associated with lexical or perceptual deficits and larger measured priming effects. Thus, co-existing striatal and limbic damage may lead to normal priming performance in some memory-impaired patients. In these instances, normal priming performance may not be mediated by a separate (implicit) memory processing system in the brain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Whatever happened to scholarly discourse? A reply to B. F. Skinner.

Comments that B. F. Skinner (see record 1988-00027-001) has presented an egregiously inaccurate characterization of humanistic psychology. The authors note that Skinnerian radical behaviorism emphasizes behavior, science, and technology, while humanistic psychologies emphasize human beings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Electrical Response of the Human Eye to Sinusoidal Light Stimulation

In order to extract maximum information from electroretingraphic waveforms obtained under clinical conditions, it is necessary to have reliable quantitative methods to characterize both the amplitude and shape of these waveforms. When sinusoidally modulated light is used to stimulate the retina, the resulting ERG potentials are, in general, not sinusoidal due to the nonlinearities in the system. However, the responses are very reproducible and can easily be characterized by a few parameters based on a Fourier analysis. The more conventional flash ERG, although usually of higher amplitude, is much less reproducible in shape and needs many more parameters to characterize completely. Amplitude and phase characteristics can be understood on the basis of a simple model for the scotopic B-wave system and additive interaction by the photopic system. Changes in amplitude and phase characteristics with various experimental conditions could be predicted and were confirmed by subsequent experiments. The ultimate goal of this work is to improve the quantitative basis for clinical electroretinography and to provide the clinician with additional data which can be useful in the diagnosis of retinal diseases.