Wavelet packet based channel equalization

Recently, considerable amount of attention is being given to the field of wavelets and wavelet packets. It has found numerous applications in signal representation, image compression and applied mathematics. In this paper, we present a channel equalization method based on wavelet packets. The proposed equalizer structure is based on the fact that for sufficiently narrowband sequences, a non-ideal channel can be modelled as an attenuation and delay. If the data sequence is used to modulate a set of narrowband wavelet packets, then no equalization is required at the receiver end. The equalization problem reduces to that of determining the delay introduced by the channel for each of the wavelet packets. A minimum square variance algorithm for adaptively choosing the delay has been proposed. This algorithm has been shown to perform as desired analytically in a simple delay channel case. Simulations have been used to study its performance in the non-ideal channel’s case and the results corroborate theoretical predictions.     

Work-site smoking policies: their population impact in Washington State

This article presents data from a population-based, random-digit dialing telephone survey of 1228 employed adults in Washington State, conducted 1989 through 1990. Eighty-one percent of men and 91% of women reported work-site smoking restrictions. Employees in work sites with no-smoking policies were less likely to be current smokers; men in work sites with policies restricting smoking smoked fewer cigarettes on both workdays and nonworkdays. Forty-eight percent of male and 53% of female smokers reported reduced smoking as a result of work-site policy. Work-site smoking policies, intended to protect against smoke exposure, may also reduce employee smoking.     

Frequency analysis of the contralateral suppression of evoked otoacoustic emissions by narrow-band noise

Yeast cells defective in the GGS1 (FDP1/BYP1) gene are unable to adapt to fermentative metabolism. When glucose is added to derepressed ggs1 cells, growth is arrested due to an overloading of glycolysis with sugar phosphates which eventually leads to a depletion of phosphate in the cytosol. Ggs1 mutants lack all glucose-induced regulatory effects investigated so far. We reduced hexokinase activity in ggs1 strains by deleting the gene HXK2 encoding hexokinase PII. The double mutant ggs1 delta, hxk2 delta grew on glucose. This is in agreement with the idea that an inability of the ggs1 mutants to regulate the initiation of glycolysis causes the growth deficiency. However, the ggs1 delta, hxk2 delta double mutant still displayed a high level of glucose-6-phosphate as well as the rapid appearance of free intracellular glucose. This is consistent with our previous model suggesting an involvement of GGS1 in transport-associated sugar phosphorylation. Glucose induction of pyruvate decarboxylase, glucose-induced cAMP-signalling, glucose-induced inactivation of fructose-1,6-bisphosphatase, and glucose-induced activation of the potassium transport system, all deficient in ggs1 mutants, were restored by the deletion of HXK2. However, both the ggs1 delta and the ggs1 delta, hk2 delta mutant lack detectable trehalose and trehalose-6-phosphate synthase activity. Trehalose is undetectable even in ggs1 delta strains with strongly reduced activity of protein kinase A which normally causes a very high trehalose content. These data fit with the recent cloning of GGS1 as a subunit of the trehalose-6-phosphate synthase/phosphatase complex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Future technology challenges in distributed interactive simulation

The paper examines the changes in computer and communications capabilities over the next 10-15 years which are most likely to affect the central components of distributed interactive simulation (DIS): manned simulators, synthetic environments, and semi-automated forces (SAF). Because these components of DIS are currently very resource intensive, improvements in computer and communications capabilities translate into direct and immediate improvements in DIS capabilities. These improved capabilities in turn allow DIS to contribute in much broader arenas, enhancing troop readiness and reducing system acquisition costs. These improvements will not all come automatically, however. Substantial planning is required to ensure that DIS can take advantage of the coming changes, rather than being overcome by them     

Involvement of spicules in the formation of vaccinia virus envelopes elucidated by a conditional lethal mutant

The envelope of immature vaccinia virions consists of a lipoprotein bilayer upon which a precise curvature is imposed by acquisition of an external scaffold of spicules. Self-assembly of this tegument was examined employing our ts 6757 mutant, which induces accumulation of immature envelopes at the restrictive temperature. With ts 6757 the envelope bilayers were also assembled into an alternative membrane configuration in the form of flexible cylinders or tubes of uniform width, lacking the spicule coat. Such tubes became extensions of or were continuous with the spherical virion envelopes. The approximately 65 kDa spicule protein, L65, product of gene D13L on the HindIII map, generally designated as a late protein, was expressed as an early function in presence of hydroxyurea, an inhibitor which entirely blocked vaccinia DNA synthesis without stopping assembly of immature envelopes. Labeling of thin sections by immunogold for electron microscopy demonstrated that L65 is present at the surface of immature virions, consistent with the position of spicules on envelopes. Transiency of the spicule scaffold was documented by (a) absence of L65 from intracellular mature virions (IMV) and (b) rapid turnover of L65 during ts 6757 virus replication at the permissive temperature but conservation of this protein at restrictive temperature, as demonstrated in pulse-chase experiments. Time-related decrease in MW of L65 to a smaller polypeptide is interpreted as evidence suggesting that the spicules attached to the envelope are assembled from a higher MW precursor.