He Bubble Concentration,Size and Strain in Implanted Aluminum by SAXS/WAXS

JOM - Alpha-radiation damage in metals is a concern for long-term radioactive storage and systems that produce nuclear energy. Accurate prediction of irradiated material properties and failure...     

Does decision quality (always) increase with the size of information samples? Some vicissitudes in applying the law of large numbers.

Adaptive decision making requires that contingencies between decision options and their relative assets be assessed accurately and quickly. The present research addresses the challenging notion that contingencies may be more visible from small than from large samples of observations. An algorithmic account for such a seemingly paradoxical effect is offered within a satisficing-choice framework. Accordingly, a choice is only made when the sample contingency describing the relative evaluation of the 2 options exceeds a critical threshold. Small samples, because of the high dispersion of their sampling distribution, facilitate above-threshold contingencies. Across a broad range of parameters, the resulting small-sample advantage in terms of hits is stronger than their disadvantage in false alarms. Computer simulations and experiments support the model predictions. The relative advantage of small samples is most apparent when information loss is low, when the threshold is high relative to the ecological contingency, and when the sampling process is self-truncated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syndrome measurement order for the [[7,1,3]] quantum error correction code

In this work, we explore the accuracy of quantum error correction depending of the order of the implemented syndrome measurements. CSS codes require that bit-flip and phase-flip syndromes be measured separately. To comply with fault-tolerant demands and to maximize accuracy, this set of syndrome measurements should be repeated allowing for flexibility in the order of their implementation. We examine different possible orders of Shor-state and Steane-state syndrome measurements for the [[7,1,3]] quantum error correction code. We find that the best choice of syndrome order, determined by the fidelity of the state after noisy error correction, will depend on the error environment. We also compare the fidelity when syndrome measurements are done with Shor states versus Steane states and find that Steane states generally, but not always, lead to final states with higher fidelity. Together, these results allow a quantum computer programmer to choose the optimal syndrome measurement scheme based on the system’s error environment.     

Entropic Contributions to Protein Stability

Thermodynamic stability is an important property of proteins that is linked to many of the trade-offs that characterize a protein molecule and therefore its function. Designing a protein with a desired stability is a complicated task given the intrinsic trade-off between enthalpy and entropy which applies for both the folded and unfolded states. Traditionally, protein stability is manipulated by point mutations which regulate the folded state enthalpy. In some cases, the entropy of the unfolded state has also been manipulated by means that drastically restrict its conformational dynamics such as engineering disulfide bonds. In this mini-review, we survey various approaches to modify protein stability by manipulating the entropy of either the unfolded or the folded states. We show that point mutations that involve elimination of long-range contacts may have a greater destabilization effect than mutations that eliminate shorter-range contacts. Protein conjugation can also affect the entropy of the unfolded state and thus the overall stability. In addition, we show that entropy can contribute to shape the folded state and yield greater protein stabilization. Hence, we argue that the entropy component can be practically manipulated both in the folded and unfolded state to modify protein stability.     

Compact beam expander with linear gratings

Novel compact beam expanders that could be useful for applications such as providing light to flat panel displays are presented. They are based on a planar configuration in which three spatially linear gratings are recorded on one transparent substrate, so as to expand a narrow incoming beam in two dimensions. We present the design and recording procedures along with results, showing a relatively uniform intensity of the wide output beam. Such expanders can serve for illuminating flat panel displays.     

Dimensionless parameters for the design of optical traps and laser guidance systems

Optical traps are routinely used for the manipulation of neutral particles. However, optical trap design is limited by the lack of an accurate theory. The generalized Lorenz-Mie theory (GLMT) solves the scattering problem for arbitrary particle size and predicts radial forces accurately. Here we show that the GLMT predicts the observed radial and axial forces in a variety of optical manipulators. We also present a dimensionless parameter beta for the prediction of axial forces. Coupled with our correlation for radial escape forces, we now have a set of two simple correlations for the practical design of radiation-force-based systems.     

STYLISTIC FEATURE SETS AS CLASSIFIERS OF DOCUMENTS ACCORDING TO THEIR HISTORICAL PERIOD AND ETHNIC ORIGIN

This research investigates classification of documents according to the ethnic group of their authors and/or to the historical period when the documents were written. The classification is done using various combinations of six sets of stylistic features: quantitative, orthographic, topographic, lexical, function, and vocabulary richness. The application domain is Jewish Law articles written in Hebrew-Aramaic, languages that are rich in their morphological forms. Four popular machine learning methods have been applied. The logistic regression method led to the best accuracy results: about 99.6% while classifying to the ethnic group of their authors or to the historical period when the articles were written and about 98.3% while classifying to both classifications. The quantitative feature set was found as very successful and superior to all other sets. The lexical and function feature sets have also been found to be useful. The quantitative and the function features are domain independent and language independent. These two feature sets might be generalized to similar classification tasks for other languages and can therefore be useful for the text classification community at large.     

Switching tasks and attention policies.

The determinants and costs of control were studied in 6 experiments examining the performance costs of changing stimulus dimension (digit value/number of elements) or attention strategies (speed/accuracy) on the first trial after task transition. Costs were compared for task shift and reconsideration only. Preparation ability was studied by presenting all transition information at the beginning of a 2-part block or only prior to each part. Results showed pronounced first-trial transition costs. Different factors were associated with stop-start and task-switching requirements. Transition costs were separate from those of basic task performance. Costs were sensitive to global control considerations and were larger for task dimension changes than for attention strategy shifts. Costs involving task dimension change, but not strategy shifts, were reduced with advanced preparation. These results are discussed in relation to contemporary models of control. A new distinction is proposed between activation and execution of control strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inter- and Intraindividual Variability in Recognition Memory: Effects of Aging and Estrogen Use.

Traditionally, studies of cognitive aging have focused on comparing the average performance of younger and older adults, whereas variability around the mean has been attributed to task-irrelevant noise. The present study examined the hypothesis that variability in memory performance increases with age and that estrogen helps temper age-related increases in variability. Postmenopausal estrogen users, estrogen and progestin (est + prog) users, and nonusers, as well as younger women, completed 16 blocks of an item-source memory task. Older women showed greater variability than younger women on measures of dispersion and consistency. Estrogen users, but not est + prog users, performed more consistently than nonusers. Overall, age-related increases in variability differed with the type of variability measured, and estrogen use, but not est + prog use, appeared to reduce age-related increases in at least 1 form of variability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)