Selective attention and the acquisition of new phonetic categories.

A class of selective attention models often applied to speech perception is used to study effects of training on the perception of an unfamiliar phonetic contrast. Attention-to-dimension (A2D) models of perceptual learning assume that the dimensions that structure listeners' perceptual space are constant and that learning involves only the reweighting of existing dimensions to emphasize or de-emphasize different sensory dimensions. Multidimensional scaling is used to identify the acoustic-phonetic dimensions listeners use before and after training to recognize the 3 classes of Korean stop consonants. Results suggest that A2D models can account for some observed restructuring of listeners' perceptual space, but listeners also show evidence of directing attention to a previously unattended dimension of phonetic contrast. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metaphors for lives and work of independent consultants.

Identifying one's metaphors can provide independent consultants with (a) a better understanding of how their skills and knowledge fit the big picture of their lives and how to use these skills to the greater benefit of their customers, (b) a better experiential flexibility, and (c) an ability to rejuvenate their lives by actively seeking out experiences that form the bases of alternative metaphors. Three metaphors for lives and work of independent human resource development consultants were identified by this qualitative study. Suggestions for practicing independent consultants and future research directions are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing-structure characterization of rheocast IN-100 superalloy

The rheocasting solidification process has been applied in the production of IN-100 nickel base superalloy. A high vacuum furnace for rheocasting superalloys was used to rheocast ingots under different processing conditions. Processing variables which were evaluated include stirring speed, isothermal stirring time, and volume fraction solid during isothermal stirring. Ingots, furnace cooled at the same rate but without stirring, were also examined for comparison with the rheocast ingots. A detailed microstructural examination was made of the resultant microstructure both on furnace cooling after stirring and on reheating to the isothermal stirring temperature followed by water quenching. Rheocasting yielded fine-grained structures, where the extent of microsegregatiori, the variation in macrostructure, and the solidification-induced porosity were found to be reduced in comparison to the unstirred ingot. The grain size and nonuniformity in the as-cast ingot were reduced by increasing the stirring speed, isothermal stirring time, or the volume fraction solid during stirring. The degree of the microsegregation decreased significantly with increasing volume fraction solid. Grain boundaries, both with and without solute enrichment, were found in the rosette-like solid particles after rheocasting, lending support to the Vogel-Cantor-Doherty model of rheocasting based on the formation of grain boundaries by strain-induced recrystallization and by sintering. It is clear from these results that the microstructure of this superalloy was significantly improved by rheocasting. Improved mechanical properties were also found and will be reported separately.     

External psychologists: Best solution for some agencies?

Discusses the effective use of external (outside the agency) psychologists, with emphasis on general problems of psychologist–institution interaction. Examples of how these problems have been managed within one large childcare institution are presented, suggestions regarding how other institutions might better employ their own external psychologists are made, and drawbacks to psychological services being offered by external psychologists on a contractual basis are identified. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers

Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in‐stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermodynamic Properties of NdSi1.8 and SmSi2 over a Wide Temperature Range

The heat capacity and enthalpy of NdSi_1.8 and SmSi₂ were investigated in the range 55-2122 K for the first time. The temperature, enthalpy and entropy of the polymorphic transformations and melting of the compounds were determined. The temperature dependencies of the principal thermodynamic functions were established, and are recommended for practical application.

     

Comparisons of fundamental solutions and particular solutions for Trefftz methods

In the Trefftz method (TM), the admissible functions satisfying the governing equation are chosen, then only the boundary conditions are dealt with. Both fundamental solutions (FS) and particular solutions (PS) satisfy the equation. The TM using FS leads to the method of fundamental solutions (MFS), and the TM using PS to the method of particular solutions (MPS). Since the MFS is one of TM, we may follow our recent book [20], [21] to provide the algorithms and analysis. Since the MFS and the MPS are meshless, they have attracted a great attention of researchers. In this paper numerical experiments are provided to support the error analysis of MFS in Li [15] for Laplace's equation in annular shaped domains. More importantly, comparisons are made in analysis and computation for MFS and MPS. From accuracy and stability, the MPS is superior to the MFS, the same conclusion as given in Schaback [24]. The uniform FS is simpler and the algorithms of MFS are easier to carry out, so that the computational efforts using MFS are much saved. Since today, the manpower saving is the most important criterion for choosing numerical methods, the MFS is also beneficial to engineering applications. Hence, both MFS and MPS may serve as modern numerical methods for PDE.     

Effect of Surface-Active Substances on the Rheological Properties of Silicon Carbide Suspensions in Paraffin

In this paper, the possibility of stabilization of SiC suspensions in paraffin (hot-molding slips) was investigated from the colloid science point of view. By considering the surface properties of finely dispersed silicon carbide, surface-active agents (fatty amine and alkylsuccinimide) which are suitable for surface modification by chemical adsorption on SiC were selected. Adsorption of fatty amines and alkylsuccinimide was carried out in model experiments in chloroform. Increasing the length of the carbon–hydrogen chain caused the adsorption to decrease, and the adsorption area of one molecule in the saturated adsorption layer to increase. The stabilizing effect of surface-active agents resulted in improved flow behavior of hot-molding slips. The efficiency of surface-active agents increased with increased adsorption layer thickness. In highly concentrated SiC hot-molding slips, a combination of alkylsuccinimide and fatty amine proved to be very efficient. This synergistic effect of long- and short-chained surface-active agents is discussed in terms of an adsorption layer model.     

Modeling secondary electron images for linewidth measurement by critical dimension scanning electron microscopy

Modeling of critical dimensions scanning electron microscopy with sub-nanometer uncertainty is required to provide a metrics and to avoid yield loss in the processing of advanced CMOS technologies. In this paper, a new approach is proposed, which includes a new Monte Carlo scheme, a new Monte Carlo code, as well as the coupling with electrostatic fields to take into account self-charging effects.