Speed limits: Orientation and semantic context interactions constrain natural scene discrimination dynamics.

The visual system rapidly extracts information about objects from the cluttered natural environment. In 5 experiments, the authors quantified the influence of orientation and semantics on the classification speed of objects in natural scenes, particularly with regard to object-context interactions. Natural scene photographs were presented in an object-discrimination task and pattern masked with various scene-to-mask stimulus-onset asynchronies (SOAs). Full psychometric functions and reaction times (RTs) were measured. The authors found that (a) rotating the full scenes increased threshold SOA at intermediate rotation angles but not for inversion; (b) rotating object or context degraded classification performance in a similar manner; (c) semantically congruent contexts had negligible facilitatory effects on object classification compared with meaningless baseline contexts with a matching contrast structure, but incongruent contexts severely degraded performance; (d) any object-context incongruence (orientation or semantic) increased RTs at longer SOAs, indicating dependent processing of object and context; and (e) facilitatory effects of context emerged only when the context shortly preceded the object. The authors conclude that the effects of natural scene context on object classification are primarily inhibitory and discuss possible reasons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Programming with C++ concepts

This paper explores the definition, applications, and limitations of concepts and concept maps in C++, with a focus on library composition. We also compare and contrast concepts to adaptation mechanisms in other languages.Efficient, non-intrusive adaptation mechanisms are essential when adapting data structures to a library’s API. Development with reusable components is a widely practiced method of building software. Components vary in form, ranging from source code to non-modifiable binary libraries. The Concepts language features, slated to appear in the next version of C++, have been designed with such compositions in mind, promising an improved ability to create generic, non-intrusive, efficient, and identity-preserving adapters.We report on two cases of data structure adaptation between different libraries, and illustrate best practices and idioms. First, we adapt GUI widgets from several libraries, with differing APIs, for use with a generic layout engine. We further develop this example to describe the run-time concept idiom, extending the applicability of concepts to domains where run-time polymorphism is required. Second, we compose an image processing library and a graph algorithm library, by making use of a transparent adaptation layer, enabling the efficient application of graph algorithms to the image processing domain. We use the adaptation layer to realize a few key algorithms, and report little or no performance degradation.     

Atomistic modeling of the electrostatic and transport properties of a simplified nanoscale field effect transistor

A first-principle model is proposed to study the electrostatic properties of a double-gated silicon slab of nano scale in the framework of density functional theory. The applied gate voltage is approximated as a variation of the electrostatic potential on the boundary of the supercell enclosing the system. With the electron density estimated by the real space Green’s functions, efficient multigrid and fast Fourier-Poisson solvers are employed to calculate the electrostatic potential from the charge density. In the representation of localized SIESTA linear combination of atomic orbitals, the Kohn-Sham equation is established and solved self-consistently for the wavefunction of the system in the local density approximation. The transmission for ballistic transport across the atomic silicon slab at small bias is calculated. The charge distribution and electrostatic potential profile in the silicon slab versus the gate voltage are then analyzed with the help of the equivalent capacitive model. Quantum confinement and short gate effects are observed and discussed.     

Copper-Tungsten Composites Sprayed by HVOF

Copper and copper-tungsten composite coatings were produced by high-velocity oxy-fuel spraying (HVOF). After initial optimization of the spraying parameters, coatings of various compositions were made and their structure, composition, mechanical, thermal, and electrical properties were characterized. The HVOF technique was able to produce rather dense coatings with minimal oxide content and relatively good mechanical and thermal properties compared to, for example, plasma-sprayed coatings; however, the achieved tungsten content was quite low.     

Cognitive–behavioral therapy to reduce weight concerns improves smoking cessation outcome in weight-concerned women.

Women smokers concerned about weight gain (N?=?219) were randomly assigned to 1 of 3 adjunct treatments accompanying group smoking cessation counseling: (a) behavioral weight control to prevent weight gain (weight control); (b) cognitive–behavioral therapy (CBT) to directly reduce weight concern, in which dieting was discouraged; and (c) standard counseling alone (standard), in which weight gain was not explicitly addressed. Ten sessions were conducted over 7 weeks, and no medication was provided. Continuous abstinence was significantly higher at posttreatment and at 6 and 12 months of follow-up for CBT (56%, 28%, and 21%, respectively), but not for weight control (44%, 18%, and 13%, respectively), relative to standard (31%, 12%, and 9%, respectively). However, weight control, and to a lesser extent CBT, was associated with attenuation of negative mood after quitting. Prequit body mass index, but not change in weight or in weight concerns postquit, predicted cessation outcome at 1 year. In sum, CBT to reduce weight concerns, but not behavioral weight control counseling to prevent weight gain, improves smoking cessation outcome in weight-concerned women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)