Dynamics of helium films

We present quantitative calculations for the static structure and the dynamics of quantum liquid films on a translationally invariant substrate. The excitation spectrum is calculated by solving the equations of motion for time-dependent one- and two-body densities. We find significant corrections to the Feynman spectrum for the phonon-like collective excitations.     

Assessing the effects of selection bias on validity data for the General Aptitude Test Battery.

Previous analyses have suggested that the database of 755 studies of the validity of the General Aptitude Test Battery (GATB) demonstrates a small but consistent positive correlation with criteria relevant to job performance. Critics have noted that some of the validity studies conducted were not included in the database and have speculated that these studies may have found negligible or even negative validities, so that the extant database is subject to selection bias. The authors use a mathematical model to estimate the magnitude of possible selection and its effects on the mean and variance of GATB validities. Although evidence of selection is found for some GATB scales and composites, the estimated effect of selection is probably too small to influence conclusions about the validity of the GATB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonetic Searching vs. LVCSR: How to Find What You Really Want in Audio Archives

A new technique is presented for searching digital audio at the word/phrase level. Unlike previous methods based upon Large Vocabulary Continuous Speech Recognition (LVCSR, with inherent problems of closed vocabulary and high word error rate), phonetic searching combines high speed and accuracy, supports open vocabulary, imposes low penalty for new words, permits phonetic and inexact spelling, enables user-determined depth of search, and is amenable to parallel execution for highly scalable deployment. A detailed comparison of accuracy between phonetic searching and one popular embodiment of LVCSR is presented along with other operating characteristics of the new technique. The current implementation for Digital Media Asset Management (DMAM) is described along with suggested applications in other domains.     

Comparison of Aspergillus ear rot and aflatoxin contamination in grain of high-oil and normal-oil corn hybrids

High-oil corn (Zea mays L.) grain is a valuable component of feed for monogastric livestock. One method of increasing the concentration of oil in corn grain is the TopCross method. With TopCross, ears of a cytoplasmic male-sterile, normal-oil hybrid are pollinated by a male-fertile, high-oil synthetic hybrid. The concentration of oil in the resulting grain is increased because of xenia effects. Kernels of high-oil corn typically have a larger germ and a smaller endosperm than kernels of comparable normal hybrids. The growth of Aspergillus flavus Link:Fr within germ tissue has been reported to be more extensive than that on the whole corn kernel; therefore, the severity of Aspergillus ear rot could be more extensive and aflatoxin concentrations could be higher in high-oil grain produced by TopCross than in grain with a lower concentration of oil. The objective of this study was to compare Aspergillus ear rot severity levels and aflatoxin concentrations in the grains of hybrids crossed with high-oil or normal-oil pollinators. Fifteen hybrids were evaluated in 1998 and 1999 in Urbana, Ill. Primary ears were inoculated with A. flavus and evaluated for susceptibility to Aspergillus ear rot and aflatoxin production in grain. Concentrations of aflatoxin and oil in corn kernels were significantly higher for high-oil hybrids than for normal-oil hybrids; however, ear rot severity was unaffected by the type of pollinator. These results suggest that grain from high-oil hybrids is at greater risk for aflatoxin contamination during some growing seasons.     

Exogenous lactobacilli fed to man - their fate and ability to prevent diarrheal disease

Clinical and microbiologic studies were conducted to evaluate the capability of exogenous lactobacilli to implant in the upper small intestine, the ability of exogenous lactobacilli to prevent enterotoxigenic Escherichia coli (ETEC) diarrhea, and the effect of lactobacillus therapy in reduction of diarrhea due to neomycin. Microbiologic studies of jejunal aspirates indicated that orally ingested Lactobacillus acidophilus and L. bulgaricus in LactinexR and L. acidophilus in Infloran BernaR survived passage through the stomach and remained viable in the proximal small bowel for three to six hours in most, not all, individuals. Challenge studies with ETEC revealed that despite the ability of lactobacilli in LactinexR to persist in the upper small intestine for several hours, the lactobacillus preparation did not prevent or alter the course of ETEC diarrhea in adults. Lactobacillus therapy with one lot of LactinexR reduced the volume and duration of neomycin-associated diarrhea, whereas another lot of LactinexR had no therapeutic effect. Thus, lot to lot variations in lactobacillus preparations may account for some conflicting results observed with lactobacillus therapy for intestinal disorders.     

Computer system buses

A common bus, carrying information and electrical power between the various components of a digital system, is as important a part of the system as the microprocessor chip itself. The electrical properties of buses often cause design problems as insufficient attention is paid to them. This article deals with the properties of three types of bus line, considering the interfacing circuitry required by each type in detail.     

On the propagation of waves from spherical and cylindrical cavities in anisotropic materials

The propagation of waves from a spherical or cylindrical cavity in an inhomogeneous anisotropic elastic solid is considered. In the first instance, integral transforms are used to provide solutions to specific boundary value problems involving elastic media exhibiting certain inhomogeneities. It is then noted that the Bergman integral operator method provides a more general analysis. Finally, an asymptotic approach having a wide range of application is discussed and employed to construct wavefront and high-frequency expansions for the solution field in general media.     

Older (but not younger) siblings facilitate false belief understanding.

Results from 4 experiments and an analysis in which all data from 444 English and Japanese children are pooled show (a) a linear increase in understanding false belief with the number of older siblings, (b) no such effect for children younger than 3 years 2 months, (c) no helpful effect of younger siblings at any age (despite the large sample), (d) no effect of siblings' gender, and (e) no helpful effect of siblings on a task measuring children's understanding of how they know something. Discussion involves speculation about how older siblings may assist children (e.g., through pretend play and mental state language) and how different aspects of a theory of mind may develop through different means. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of total organic carbon and UV-B radiation on zinc toxicity and bioaccumulation in aquatic communities

The effects of total organic carbon (TOC) and UV-B radiation on Zn toxicity and bioaccumulation in a Rocky Mountain stream community were assessed in a 10-d microcosm experiment. We predicted that TOC would mitigate Zn toxicity and that the combined effects of Zn and UV-B would be greater than Zn alone. However, TOC did not mitigate Zn toxicity in this study. In fact, treatments with TOC plus Zn had significantly lower community respiration as compared with the controls and Zn concentrations associated with the periphyton increased in the presence of TOC. UV-B had no additive effect on periphyton Zn accumulation or community respiration. Heptageniid mayflies (Ephemeroptera) were particularly sensitive to Zn, and reduced abundances were observed in all Zn treatments. UV-B did not additionally impact Heptageniid abundances; however UV-B did have a greater effect on macroinvertebrate drift than Zn alone. Ephemeroptera, Plecoptera, and Trichoptera (groups typically classified as sensitive to disturbance) were found in highest numbers in the drift of UV-B + Zn treatments. Measures of Zn accumulation in the caddisfly Arctopsyche grandis, periphyton biomass, and total macroinvertebrate abundance were not sufficiently sensitive to differentiate effects of TOC, UV-B, and Zn. These results indicate that UV-B and TOC affect Zn bioavailability and toxicity by impacting species abundance, behavior, and ecosystem processes.