Trial-spacing effects in Hermissenda suggest contributions of associative and nonassociative cellular mechanisms.

In behaving Hermissenda, a preparatory conditioned response developed across repeated pairings of light (conditioned stimulus; CS) and rotation (unconditioned stimulus; US) with intertrial intervals (ITIs) of 60 and 120 s, but not 30 s. Likewise, contiguous in vitro stimulation of the visual and vestibular receptors, an analog of behavioral conditioning, resulted in an increase in the input resistance (i.e., excitability, a correlate of conditioning) of the B photoreceptors of the Hermissenda's eye, but only with ITIs greater than 60 s. Calcium signaling in the B cell, critical to the induction of this neuronal plasticity, was attenuated with shorter ITIs owing to (a) a reduction of the light-induced generator potential and hence voltage-dependent Ca2+ influx during the light CS, (b) a depression of the Ca2+ current that persisted throughout shorter ITIs, and (c) a steady-state inactivation of the Ca2+ current as a result of a sustained depolarization persisting from the previous trial. These results are consistent with a 2-process theory of associative learning in which a primary process (Ca2+ influx) may be opposed by a secondary process (depression of the Ca2+ current) during short ITIs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The performance of materials management in multi-level product structures with demand uncertainty and back-ordering

This paper investigates the impact of planned backordering in the context of demand uncertainty for a multi-level product structure environment operating under a rolling horizon. To this end, the performance of lot sizing algorithms incorporating back-orders is evaluated for such an environment by means of simulation modeling. Given the presence of demand uncertainty, the results suggest that backordering algorithms can sometimes improve performance.     

Facilities planning and design with microcomputers

This paper describes an interactive layout design program, that is written in LISP and runs on IBM PC, XT, AT, or compatible microcomputers. This program follows a construction algorithm and generates a block diagram     

Parent training of toddlers in day care in low-income urban communities.

The authors tested a 12-week parent training program with parents (n=208) and teachers (n=77) of 2-3-year-olds in day care centers serving low-income families of color in Chicago. Eleven centers were randomly assigned to 1 of 4 conditions: (a) parent and teacher training (PT + TT), (b) parent training (PT), (c) teacher training (TT), and (d) waiting list control (C). After controlling for parent stress, PT and PT + TT parents reported higher self-efficacy and less coercive discipline and were observed to have more positive behaviors than C and TT parents. Among toddlers in high-risk behavior problem groups, toddlers in the experimental conditions showed greater improvement than controls. Most effects were retained 1 year later. Benefits were greatest when parents directly received training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Treatment of plasticized PVC to reduce plasticizer/solvent migration: optimization with an experimental design

This work deals with mass transfers between liquid food and PVC packaging. A treatment which reduces the migration both of plasticizer toward a liquid food simulant and the liquid has been investigated. The treatment is a two step process: (1) soaking in a liquid and (2) drying at various temperatures. Some process parameters, such as time and temperature of soaking, temperature and time of drying, influence the treatment efficacy. The best values consider in from these factors were found due to experimental designs and the physical significance of the results is discussed. © 2003 Society of Chemical Industry     

Controlled terminology for clinically-relevant indexing and selective retrieval of biomedical images

Received: 5 April 1997 / Revised: 10 July 1997 / Accepted: 5 August 1997     

A molecular genetic model of astrocytoma histopathology

As the molecular events responsible for astrocytoma formation and progression are being clarified, it is becoming possible to correlate these alterations with the specific histopathological and biological features of astrocytoma, anaplastic astrocytoma and glioblastoma multiforme. In WHO grade II astrocytomas, autocrine stimulation by the plateletderived growth factor system coupled with inactivation of the p53 gene may lead to a growth stimulus in the face of decreased cell death with slow net growth ensuing. Such cells would also have defective responses to DNA damage and impaired DNA repair, setting the stage for future malignant change. Such biological scenarios recapitulate many of the clinicopathological features of WHO grade II astrocytomas. Anaplastic astrocytomas further display release of a critical cell cycle brake that involves the CDKN2/p16, RB and CDK4 genes. This results in mitoses seen histologically; clinically, there is more conspicuous, rapid growth. Finally, glioblastomas may emerge from the microenvironmental outgrowth of more malignant clones in a complex vicious cycle that involves necrosis, hypoxia, growth factor release, angiogenesis and clonal selection; growth signals mediated by activation of epidermal growth factor receptors may precipitate glioblastomas. It is clear as well that glioblastoma multiforme can arise via a number of independent genetic pathways, although the clinical significance of these distinctions remains unclear.     

Cloning of a highly conserved human protein serine-threonine phosphatase gene from the glioma candidate region on chromosome 19q13.3

Allelic loss studies have suggested that a glioma tumor suppressor gene resides in a 425-kb region of chromosome 19q, telomeric to D19S219 and centromeric to D19S112. Exon amplification of a cosmid contig spanning this region yielded four exons with high homology to a rat protein serine-threonine phosphatase from a cosmid approximately 100 kb telomeric to D19S219. Isolation of a near full-length cDNA from a human fetal brain cDNA library revealed a protein serine-threonine phosphatase with a tetratricopeptide motif, almost identical to human PPP5C (PP5) and highly homologous to rat PPT. Northern blotting demonstrated expression in most tissues, including brain. Primary and cultured gliomas were studied for genetic alterations in this gene using pulsed-field gel electrophoresis, routine Southern blots, and genomic DNA-and RNA-based single-strand conformation polymorphism analysis. Genomic alterations were were not detected in any of the gliomas, and all studied gliomas expressed the gene, suggesting that this phosphatase is not the putative chromosome 19q glioma tumor suppressor gene.