Plastic deformation of hafnium-oxygen alloys

The plastic flow kinetics of hafnium single crystals and polycrystals of a range of oxygen contents were investigated over the temperature range of 77 to 873 K employing the technique of incrementally changing the temperature and strain rate. It was found that τ*₀ ≈ 2.4 x 10⁻³ μ₀√Ci, where τ*₀ is the effective CRSS extrapolated to 0K, μ₀ the modulus at OK, and Ci the total interstitial content (0.05 to 1.16 at. pct). Using the theory of thermally activated deformation, it is concluded that overcoming local interstitial obstacles is rate controlling over the temperature range of 77 to 750 K and that the obstacles are characterized by a Gibbs activation free energy δG at 0K and zero effective stress of ∼1.7 eV (0.14 μ₀b³). Results for single crystals and polycrystals are in agreement using a Taylor factor of 3.5 for the ratio of tensile to shear stress. W. R. Tyson is on leave from the Physics Department of Trent University, Peterborough, Ontario, Canada.     

Analysis of keratan sulfate oligosaccharides by electrospray ionization tandem mass spectrometry

Keratan sulfate (KS) is a glycosaminoglycan consisting of repeating disaccharide units composed of alternating residues of d-galactose and N-acetyl-d-glucosamine linked beta-(1-4) and beta-(1-3), respectively. In this study, electrospray ionization tandem mass spectrometry (ESI-MS/MS) was employed to identify keratan sulfate oligosaccharides. Two nonsulfated disaccharide isomers and two monosulfated disaccharide isomers were distinguished through MS/MS. In MS(1) spectra of multiply sulfated KS oligosaccharides, the charge state of the most abundant molecular ion equals the number of sulfates. Subsequent MS(2) and MS(3) spectra of mono-, di-, tri-, and tetrasulfated KS oligosaccharides and sialylated tetrasaccharides reveal diagnostic ions that can be used as fingerprint maps to identify unknown KS oligosaccharides. Based on the pattern of fragment ions, the compositions of an oligosaccharide mixture from shark cartilage KS and of two enzyme digests of bovine corneal KS were determined directly, without prior isolation of individual oligosaccharides by HPLC or other methods.     

An information fidelity criterion for image quality assessment using natural scene statistics.

Measurement of visual quality is of fundamental importance to numerous image and video processing applications. The goal of quality assessment (QA) research is to design algorithms that can automatically assess the quality of images or videos in a perceptually consistent manner. Traditionally, image QA algorithms interpret image quality as fidelity or similarity with a "reference" or "perfecft" image in some perceptual space. Such "full-referenc" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by arbitrary signal fidelity criteria. In this paper, we approach the problem of image QA by proposing a novel information fidelity criterion that is based on natural scene statistics. QA systems are invariably involved with judging the visual quality of images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of natural signals, that is, pictures and videos of the visual environment. Using these statistical models in an information-theoretic setting, we derive a novel QA algorithm that provides clear advantages over the traditional approaches. In particular, it is parameterless and outperforms current methods in our testing. We validate the performance of our algorithm with an extensive subjective study involving 779 images. We also show that, although our approach distinctly departs from traditional HVS-based methods, it is functionally similar to them under certain conditions, yet it outperforms them due to improved modeling. The code and the data from the subjective study are available at.     

Structure-aided optimization of kinase inhibitors derived from alsterpaullone

In order to perform computer-aided design of novel alsterpaullone derivatives, the vicinity of the entrance to the ATP-binding site was scanned for areas that could be useful as anchoring points for additional protein-ligand interactions. Based on the alignment of alsterpaullone in a CDK1/cyclin B homology model, substituents were attached to the 2-position of the parent scaffold to enable contacts within the identified areas. Synthesis of the designed structures revealed three derivatives (3-5) with kinase-inhibitory activity similar to alsterpaullone. The novel 2-cyanoethylalsterpaullone (7) proved to be the most potent paullone described so far, exhibiting inhibitory concentrations for CDK1/ cyclin B and GSK-3beta in the picomolar range.     

Validity comparison of behavior counts and ratings by knowledgeable informants.

Argues that the reliability and validity of behavioral ratings as an assessment technique can be demonstrated when assessments are based on multiple raters and are validated against frequency counts based on adequate samples of behavior. This argument is illustrated by the observations of dependency and dominance in 56 preschoolers by 9 trained undergraduate observers. Besides supporting the reliability and validity of scores based on multiple ratings, the analyses also indicated that small samples of behavioral observations did not capture the stability of personality characteristics. Methodological implications for the use of ratings and behavior counts and conceptual implications for the consistency of personality are discussed. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Childhood origins of psychopathology.

Discusses family interaction and genetic influences on the development of psychopathology in childhood. Mounting evidence suggests that genetic factors significantly influence most personality traits, most forms of psychopathology, and sex differences in the prevalence of psychopathology. The sex and temperamental characteristics of children affect parent–child interaction as does the strength of the allegiance pressures emanating from a mother and father locked in hostile conflict. Children who are opposite to the sex of the more powerful parent experience the greatest allegiance conflict and consequent psychopathology. Also moderating the pathogenic effects of parental conflict are consistency of parental love and the ruthlessness of efforts to win the child's allegiance. The practical implications of these views are discussed. (3l ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Licensure in psychology: Alternative directions.

The licensing of psychologists has become an area of intense professional interest. Attempts to provide historical overviews and current data on the status of licensing regulations have become common. This article critiques existing regulations by examining assumptions implicit in the development of licensing procedures. The implications of such assumptions for professional psychology are discussed, and guidelines for alternative licensure developments are presented. The importance of developing valid measures of entry-level and continued professional competence is emphasized. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)