Diffusion kinetics for divacancies in the bcc lattice

In this letter we employ high-precision Monte Carlo simulations to investigate tracer diffusion kinetics for diffusion via divacancies in the bcc lattice. We utilize the mechanisms originally identified by Mehrer in which the divacancy can move by nearest-neighbour jumps with stable first-nearest-neighbour, second-nearest-neighbour and fourth-nearest-neighbour configurations of the divacancy. The tracer correlation factor and the 'impurity-form' correlation factor were found to be some 4-6% lower than those found by the matrix method. The tracer diffusion data and isotope effect for sodium were revisited in terms of monovacancy and divacancy contributions. The main change is a revision upwards from 0.55 to 0.61 of the j K kinetic factor for divacancies.     

Dislocations and cracks at Vickers indentations in (0 0 0 1) GaN single crystals

Single-crystal (0 0 0 1) GaN samples have been deformed with a Vickers indenter at room temperature using loads in the range from 0.02 to 4.90 N. Dislocations and cracks at the indentations were examined by means of scanning electron microscopy, cathodoluminescence, light microscopy and transmission electron microscopy. Geometrical relations could be found between the dislocation arrangement, cracks and the orientation of the indenter. The orientation of the indenter has only a slight effect on the dislocation pattern, but the crack system is predominantly determined by the symmetry and the orientation of the indenter.     

Indentation hardnesses of semiconductors and a scaling rule

The Vickers hardnesses of 15 semiconductors, namely Si, Ge, SiC, AlN, GaN, GaP, GaAs, GaSb, InP, InAs, InSb, ZnO, ZnSe, ZnTe and CdTe, have been investigated from room temperature to their melting points. The temperature dependences of the Vickers hardness H V of 11 of these semiconductors, namely those with a cubic structure, obey a universal relationship when H V and the temperature T are scaled respectively by the shear modulus G and by Gb 3 / k B, with b being the magnitude of the Burgers vector. The scaling rule is the same as that found for the temperature dependence of the critical shear stress c for the {111}<110> slip system, satisfying the relationship H V = (70-100) c .     

Locating dysprosium dopant atoms in the Bi2Sr2CaCu2Oy unit cell: Direct-space chemical crystallography

The position of Dy in the unit cell of Bi2Sr2CaCu2Oy has been determined by a real-space method. This is compared with the reciprocal-space atom location by channelling-enhanced microanalysis (ALCHEMI) method.     

Nanodefects in nanostructures

The notion of nanodefects (topological defects of nanoscale translational order) in nanostructures of various types is introduced. Experimental data reported in the literature are discussed giving direct evidence for the existence of nanodefects in self-assembled periodically ordered nanostructures such as arrays of quantum dots, self-assembled superlattice films of nanoparticles, and arrays of carbon nanotubes. Also, the specific geometric features of perfect and partial cellular dislocations (being a kind of nanodefect) and their role in superplastic deformation in nanocrystalline materials are considered.     

Sleep disturbance and emotion dysregulation as transdiagnostic processes in a comorbid sample

Sleep disturbance and emotion dysregulation have been identified as etiologic and maintaining factors for a range of psychopathology and separate literatures support their relationships to anxiety, depression, PTSD, and alcohol dependence (AD) symptom severity. Previous studies have examined these relationships in isolation, failing to account for the high rates of comorbidity among disorders. It is not yet known whether these processes uniquely predict symptom severity in each of these domains. Participants were 220 patients in residential substance abuse treatment, who had experienced a potentially traumatic event and exceeded screening cutoffs for probable PTSD and problematic alcohol use. Controlling for emotion dysregulation and the interrelationships among the outcome variables, insomnia was uniquely associated with anxiety (B = .27, p < .001), depression (B = .25, p < .001), PTSD (B = .22, p < .001), and AD (B = .17, p = .01) symptom severity. Similarly, controlling for insomnia, emotion dysregulation was uniquely associated with anxiety (B = .40, p < .001), depression (B = .47, p < .001), PTSD (B = .38, p < .001), and AD (B = .26, p < .001) symptom severity. Insomnia and emotion dysregulation appear to be transdiagnostic processes uniquely associated with symptom severity across a number of different domains and might be important treatment targets for individuals with PTSD and AD.     

Socio-ecological influences of attitudes toward disability among Kenyan undergraduate students

This study examined personal and contextual variables as predictors of attitudes toward disability at a Kenyan higher education setting. Participants were a convenience sample of 309 undergraduate students at a Kenyan university enrolled in Sociology, Social Work, Psychology, Political Science, and Public Administration majors. Data on attitudes were collected using the Attitudes Towards Disabled Persons scale (ATDP: Antonac & Livneh, 1988). A cross-sectional survey design was employed for data collection, and a multiple regression analysis was used for data analysis. Results revealed that the model was significant: F (9, 250)?=?2.784, p?=?0.004. However, only age (β?=?0.173, p?=?0.044) significantly predicted attitudes towards disability, indicating older students held more positive attitudes than their younger counterparts. Older students had a more favourable attitude towards people with disabilities than younger students. Seniority, by age, is highly valued in Africa than perhaps anywhere in the world. Kenyan older adults may be key to enhancing favourable attitudes toward individuals with disabilities in Kenya as well as interventions aimed at changing negative attitudes towards people with disabilities.     

Community as Outsider Witness: Utilising Community Members in the Reconstitution of Problem-Saturated Identities

This study explored community members' ability to enlist discourses affirming of psychiatric patients' quest for generative identities. The participants were members of the public who attended an exhibition of psychiatric patients' artwork (n = 7, age range 18–55). A Foucauldian discourse analysis was used to analyse the research interviews. Results revealed that the majority of community members used dominant cultural discourses to speak about psychiatric patient-artists. These discourses conferred a problem-saturated identity on to psychiatric patients. We conclude that community members can be recruited as outsider witnesses to support psychiatric patients' search for generative identities, provided community members resist discourses that produce problem-saturated identity conclusions.     

Development and Validation of the Xhosa Translations of the Beck Inventories: 1. Challenges of the Translation Process

This article describes the translation of the Beck Depression Inventory-II, the Beck Hopeless Scale, and the Beck Anxiety Inventory, into Xhosa the language spoken in the Eastern Cape of South Africa. The processes of translation, back-translation and committee discussion failed to yield trustworthy translations because of practical difficulties in working with translators. Critical words and phrases were identified which gave rise to lack of agreement. For each, a range of options was generated and the advantages and disadvantages evaluated in terms of criteria such as conceptual and idiomatic equivalence, and extensiveness of usage. Examples are given of the problems encountered and the way in which final decisions were made. A pilot clinical trial demonstrated the acceptability of the translated instruments. Two further articles report the psychometric evaluation of the translated scales.     

Development and Validation of the Xhosa Translations of the Beck Inventories: 2. Item Analysis,Internal Consistency and Factor Analysis

The Beck Depression Inventory-II (BDI-II), the Beck Anxiety Inventory (BAI), and the Beck Hopelessness Scale (BHS) were translated into Xhosa, a language widely spoken in South Africa to yield translated scales referred to as the XBDI-I (Xhosa BDI-II), the XBAI (Xhosa BAI) and the XBHS (Xhosa BHS). These scales were administered to a sample of 122 Xhosa respondents which included students and patients. The psychometric properties of the translated scales were comparable to those of the original English versions. Measures of internal consistency were as high as those for the validation studies in the USA and good item-scale correlations were obtained. This suggests that the translation yielded clinically useful scales which tap symptoms that are largely culturally universal.