Employment test validation for minority and nonminority telephone operators.

Validated 10 pencil-and-paper tests against telephone operator proficiency measured in specially developed job simulations. Job analysis information plus patterns of validity coefficients for a nationwide sample (N = 1,091) working in 3 different telephone operator jobs indicated that a number of behavioral dimensions were common to all 3 jobs. Data, therefore, were combined across jobs and analyzed separately for Black, Spanish-surnamed, and White operators. A composite of the 4 maximally predictive tests was significantly predictive of a composite criterion for all ethnic groups, but less so for the Spanish-surnamed. Ethnic regression-line slopes and intercepts differed significantly. The common regression equation generally did not underpredict minority operator proficiency, and a composite test cutoff considered fair for minority and nonminority applicants is recommended. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apolipoprotein E in the brain and its role in Alzheimer's disease

Recent evidence indicates that apolipoprotein E (apoE) plays a central role in the brain response to injury. The coordinated expression of apoE and its main receptor, the apoE/apoB (LDL) receptor, appears to regulate the transport of cholesterol and phospholipids during the different phases of the reinnervation process. The recent discovery that a peculiar form of apoE, the apoE4, is strongly linked to both sporadic and familial late onset Alzheimer's disease (AD) raises the possibility that a dysfunction of the lipid transport system associated with compensatory sprouting and synaptic remodelling could be central to the AD process. The role of apoE in the central nervous system (CNS) is particularly important in relation to the function of the cholinergic system which relies to a certain extent on the integrity of phospholipid homeostasis in neurons. Recent evidence suggests that apoE4 allele has a direct impact on cholinergic function in AD.     

Cytotoxic T-cell-derived granzyme B activates the apoptotic protease ICE-LAP3

Cytotoxic T lymphocytes (CTLs) and natural killers (NK) cells provide immune surveillance against viruses and neoplasms, and play a central role in the pathogenesis of autoimmune disease, AIDS and graft rejection. Thus, it is important to understand the precise molecular mechanism(s) whereby cytotoxic lymphocytes destroy susceptible target cells. Granule-mediated cytotoxicity requires a combination of both perforin and granzyme B. Perforin polymerizes to form transmembrane channels and presumably allows granzyme B access to target cell substrates, which until recently, were unknown. One clue to the identity of the physiological substrate(s) activated by granzyme B comes from its unusual specificity for cleaving synthetic substrates after aspartate residues. Members of the ICE/CED-3 family of cysteine proteases are prime candidates as they are important apoptotic effectors and are expressed as zymogens, which can be processed to form active heterodimeric enzymes after cleavage at specific aspartate residues. Previous studies have shown that granzyme B proteolytically activates the cell death effector Yama/CPP32/apopain (referred to here as Yama). Here we report that granzyme B also activates ICE-LAP3/Mch3/CMH-1 (referred to here as ICE-LAP3), which, along with Yama and Mch2, forms a subset of the ICE/CED-3 family of cysteine proteases most closely related to the Caenorhabditis elegans cell death gene, CED-3. Importantly, Jurkat T cells incubated with granzyme B and a sublytic concentration of perforin undergo apoptosis, which is preceded by the activation of endogenous ICE-LAP3. Thus, we propose that granzyme B mediates apoptosis by directly engaging the target cell's death effector machinery, which is probably composed of an arsenal of intracellular, CED-3-like cysteine proteases.     

Immediate serial recall, word frequency, item identity and item position.

Investigated the effect of frequency on item recall using phonologically similar vs distinct lists within a standard immediate serial recall paradigm. 18 Ss (mean age 29 yrs) completed an immediate serial recall task, where the lists to be recalled consisted of either high-, medium-, or low-frequency items and were also either phonologically similar or distinct. Results show that increasing frequency enhanced item information recall but had no effect on order recall. Conversely, increasing phonological similarity had a detrimental effect on order recall but no significant effect on item recall. The authors maintain that both results reflect retrieval processes where degraded representations are reconstructed on the basis of long-term knowledge. Low-frequency words have reduced accessibility, lowering the probability of correct reconstruction, and phonologically similar items are more easily confused with other recall candidates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal control of an induction heating process using automatic differentiation

We consider an optimal control problem arising in an induction heating process. The main difficulty is to obtain accurate and efficient derivatives of the discrete form of the cost function. In this work we use automatic differentiation. Unlike numerical differentiation based on finite differences, derivatives generated by automatic differentiation are free of truncation error. Numerical results show the performance of the method in terms of accuracy and computational efficiency. Copyright © 2005 John Wiley & Sons, Ltd.     

Flow reversal reactor for the catalytic combustion of lean methane mixtures

This paper describes an experimental investigation of a pilot scale reverse flow reactor for the catalytic destruction of lean mixtures of methane in air. It was found that using reverse flow it was possible maintain elevated reactor temperatures which were capable of achieving high methane conversion of methane in air streams at methane concentrations as low as 0.19% by volume. The space velocity, cycle time and feed concentration are all important parameters that govern the operation of the reactor. Control of these parameters is important to prevent the trapping of the thermal energy within the catalyst bed, which can limit the amount of energy that can be usefully extracted from the reactor.     

Modeling and implementation of 5G edge caching over satellite

The fifth‐generation (5G) wireless networks have to deal with the high data rate and stringent latency requirements due to the massive invasion of connected devices and data‐hungry applications. Edge caching is a promising technique to overcome these challenges by prefetching the content closer to the end users at the edge node's local storage. In this paper, we analyze the performance of edge caching 5G networks with the aid of satellite communication systems. First, we investigate the satellite‐aided edge caching systems in two promising use cases: (a) in dense urban areas and (b) in sparsely populated regions, eg, rural areas. Second, we study the effectiveness of satellite systems via the proposed satellite‐aided caching algorithm, which can be used in three configurations: (a) mono‐beam satellite, (b) multi‐beam satellite, and (c) hybrid mode. Third, the proposed caching algorithm is evaluated by using both empirical Zipf‐distribution data and the more realistic Movielens dataset. Last but not least, the proposed caching scheme is implemented and tested by our developed demonstrators which allow real‐time analysis of the cache hit ratio and cost analysis.     

France telecom's introduction of switched broadband business services

In order to cope with the growth of video transmissions in France, France Telecom will commercially introduce switched broadband business services by June 1990. A broadband network based on a meshed network of optical fibres will provide one-way point-to-multipoint (including point-to-point) connections, available on reservation. This network will link non-blocking 32 × 32 or 64 × 64 space switches that can cross-connect different signals, including analog SPFM (square pulse frequency modulation) video, HDB3 34 Mb/s and CMI 140 Mb/s digital signals.