Modelling of AlAs/GaAs interfacial structures using high-angle annular dark field (HAADF) image simulations

High angle annular dark field (HAADF) image simulations were performed on a series of AlAs/GaAsinterfacial models using the frozen-phonon multislice method. Three general types of models were considered—perfect, vicinal/sawtooth and diffusion. These were chosen to demonstrate how HAADFimage measurements are influenced by different interfacialstructures in the technologically important III–V semiconductor system. For each model, interfacial sharpness was calculated as a function of depth and compared to aberration-corrected HAADF experiments of two types of AlAs/GaAs interfaces. The results show that the sharpness measured from HAADF imaging changes in a complicated manner with thickness for complex interfacialstructures. For vicinal structures, it was revealed that the type of material that the probe projects through first of all has a significant effect on the measured sharpness. An increase in the vicinal angle was also shown to generate a wider interface in the random step model. The Moison diffusion model produced an increase in the interface width with depth which closely matched the experimental results of the AlAs-on-GaAs interface. In contrast, the interface width decreased as a function of depth in the linear diffusion model. Only in the case of the perfect model was it possible to ascertain the underlying structure directly from HAADFimage analysis

Characterisation of InAs/GaAs short period superlattices using column ratio mapping in aberration-corrected scanning transmission electron microscopy

The image processing technique of columnratiomapping was applied to aberration-corrected high angle annular dark field (HAADF) images of shortperiod MBE (molecular beam epitaxy) grown InAs/GaAssuperlattices. This method allowed the Indium distribution to be mapped and a more detailed assessment of interfacial quality to be made. Frozen-phonon multislice simulations were also employed to provide a better understanding of the experimental columnratio values. It was established that ultra-thin InAs/GaAs layers can be grown sufficiently well by MBE. This is despite the fact that the Indium segregated over 3–4 monolayers. Furthermore, the effect of the growth temperature on the quality of the layers was also investigated. It was demonstrated that the higher growth temperature resulted in a better quality superlattice structure

Insertion loss measuring apparatus having transformer means connected across a pair of bolometers Patent

High impedance alternating current sensing transformer device between two bolometers for measuring insertion loss of test componen

The Collaborative Problem-Solving Approach with Traumatized Children: Its Effectiveness in the Reduction of Locked Seclusion in an Inpatient Psychiatric Setting

Aggressive or explosive behaviors in children typically occur within the context of a variety of psychiatric diagnoses and pose additional challenges when children present with histories of abuse. These behaviors are often interpreted as deliberate or noncompliant and management of these extreme behaviors often results in locked seclusion in most inpatient psychiatric settings. Locked seclusion remains controversial at best and raises legal and ethical issues regarding its safe and therapeutic use. This retrospective quantitative study evaluated the effectiveness of the Collaborative Problem-Solving (CPS) approach as a less restrictive behavioral intervention on an inpatient child psychiatric unit with children ages 5-12 years that introduced the CPS approach during a nine month performance improvement project from July 1, 2006 - March 31, 2007. This study sought to determine what variables, if any, impacted the use of locked seclusion before, during, and after CPS implementation and whether children with histories of abuse were placed in locked seclusion at a significantly different rate relative to admissions of children who did not have histories of abuse. Erik Erikson\u27s Theory of Psychosocial Development served as the theoretical framework. The closed medical record review involved 197 admissions and 167 children. All data were analyzed in two parts: the entire nine month period of 197 admissions and by time period, based on when the CPS intervention was introduced and implemented on the unit. Length of stay was the only variable statistically significant during the nine month period (n=197) and third time period of January -March 2007 (n=65) when CPS was fully implemented and assessed. This finding suggests that a child\u27s longer length of stay may have had a relationship with being placed in locked seclusion. When length of stay was controlled as an influence with history of abuse, the variable of interest for this study, children with histories of abuse for the nine month period were not significantly more likely of being placed in locked seclusion than children without histories of abuse; for the third time period, they were found to be almost eight times less likely of being placed in locked seclusion with an odds ratio of 7.81. Although these findings suggest a favorable response to the CPS approach and that behaviors associated with traumatized children were normalized to that of their peer group, the results must be considered with caution. There were many limitations to the initial project and any inferred success with abused children and the CPS approach is based on statistical outcomes only. Other variables not measured or controlled must be considered as potential influences that may have impacted these outcomes. As such, future research evaluating CPS effectiveness with traumatized children is recommended

Cyclical Changes in Short-Run Earnings Mobility in Canada, 1982-1996

The paper by Charles M. Beach and Ross Finnie represents the first attempt to quantify short-term or cyclical changes in earnings mobility in Canada. Mobility analysis can be seen as a complement to the analysis of income distribution. For a given degree of earnings inequality, more earnings mobility corresponds to securing greater labour market opportunity. Using longitudinal income-tax-based data, the authors divide the employed population into eight age/sex groups: entry workers (20–24), younger workers (25–34), prime-age workers (35–54), and older workers (55–64) for both sexes; and divide the earnings distribution into lower, middle and upper regions or earnings intervals based on median earnings levels for the distribution as a whole, and calculate the proportion of workers in each group for all years over the 1982–96 period. They also develop transition matrices that show the probability of moving from one earnings interval to another over a one-year period. They find that there have been major cyclical changes in earnings polarization and that these changes have been concentrated in recessions, notably in the 1990–92 downturn. They also find that men in particular experienced a marked decrease in their net probability of upward mobility in the earnings distribution during recessions, as the probability of moving up fell sharply as did the probability of moving down. The results of the paper are particularly relevant for an understanding of how earnings mobility may be affected by the current economic slowdown.Earnings Mobility, Income Mobility, Mobility, Income, Earnings, Distribution, Income Distribution, Earnings Distribution, Earnings Inequality, Recession, Cyclical

Evaluation of a spring-powered captive bolt gun for killing kangaroo pouch young

Context: During commercial harvesting or non-commercial kangaroo culling programs, dependent young of shot females are required to be euthanased to prevent suffering and because they would be unlikely to survive. However, the current method for killing pouch young, namely a single, forceful blow to the base of the skull, is applied inconsistently by operators and perceived by the public to be inhumane. Aims: To determine whether an alternative method for killing pouch young, namely a spring-operated captive bolt gun, is effective at causing insensibility in kangaroo pouch young. Methods: Trials of spring-operated captive bolt guns were conducted first on the heads of 15 dead kangaroo young and then on 21 live pouch young during commercial harvesting. We assessed the effectiveness at causing insensibility in live animals and damage caused to specific brain areas. We also measured depth of bolt penetration and skull thickness. Performance characteristics (e.g. bolt velocity) of two types of spring-operated guns were also measured and compared with cartridge-powered devices. Key results: When tested on the heads of dead animals, the spring-operated captive bolt gun consistently produced a large entrance cavity and a well defined wound tract, which extended into the cerebrum, almost extending the full thickness of the brain, including the brainstem. When tested on live pouch young, the captive bolt gun caused immediate insensibility in only 13 of 21 animals. This 62% success rate is significantly below the 95% minimum acceptable threshold for captive bolt devices in domestic animal abattoirs. Failure to stun was related to bolt placement, but other factors such as bolt velocity, bolt diameter and skull properties such as thickness and hardness might have also contributed. Spring-operated captive bolt guns delivered 20 times less kinetic energy than did cartridge-powered devices. Conclusions: Spring-operated captive bolt guns cannot be recommended as an acceptable or humane method for stunning or killing kangaroo pouch young. Implications: Captive bolt guns have potential as a practical alternative to blunt head trauma for effective euthanasia and reducing animal (and observer) distress. However, operators must continue to use the existing prescribed killing methods until cartridge-powered captive bolt guns have been trialled as an alternative bolt propelling method. Additional keywords: animal welfare, blunt trauma, culling, euthanasia, humaneness, kangaroo harvesting

The Impact of Macroeconomic Conditions on the Instability and Long-Run Inequality of Workers’ Earnings in Canada

This paper examines the variability of workers’ earnings in Canada over the period 1982‑1997. Using a large panel of tax file data, we decompose total variation in earnings across workers and time into a long-run inequality component between workers and an average earnings instability component over time for workers. We find an increase in earnings variability between 1982‑89 and 1990‑97 that is largely confined to men and largely driven by widening long-run earnings inequality. Second, the pattern of unemployment rate and GDP growth rate effects on these variance components is not consistent with conventional explanations and is suggestive of an alternative paradigm of how economic growth over this period widens long-run earnings inequality. Third, when unemployment rate and GDP growth rate effects are considered jointly, macroeconomic improvement is found to reduce the overall variability of earnings as the reduction in earnings instability outweighs the widening of long-run earnings inequality.Le marché du travail canadien, au cours des décennies 1980 et 1990, a connu de nombreux changements eu égard à la structure commerciale, à la technologie de production, aux aménagements atypiques du travail, aux fluctuations démographiques, à la vulnérabilité des travailleurs, pour ne nommer que ceux-là. Cet essai analyse le caractère variable de la rémunération des travailleurs canadiens au cours de la période 1982 et 1997 et l’ampleur de ces variations en termes d’indicateurs macroéconomiques, du taux de chômage et du taux de croissance du PIB au cours de cette période. Nous reprenons les explications habituelles des changements cycliques au plan de l’inégalité de la rémunération avec l’éclairage de ces changements caractérisés au sein du marché du travail canadien.Notre essai fait appel à un large éventail de données de l’impôt sur le revenu provenant de la banque de Données administratives longitudinales (DAL) de Statistique Canada au cours de la période 1982–1997 et utilise une méthodologie de ventilation d’écarts de la variation totale des gains entre les travailleurs au cours de la période pour en dégager une composante permanente et de longue période entre les travailleurs et une composante transitoire ou d’instabilité des gains dans le temps chez les travailleurs. Ces trois mesures de variabilité sont toutes converties en une fonction des indicateurs macroéconomiques identifiés plus haut par une régression multivariée. Jusqu’ici, dans les écrits sur le sujet, les modèles de variance dans les configurations de gains faisaient appel aux techniques structurelles de séries temporelles. Ces dernières exigent une période de temps d’une longueur homogène au plan des gains. Par conséquent, ces études ont ciblé seulement les travailleurs masculins dans la force de l’âge entretenant un lien étroit avec le marché du travail. Cet essai s’en tient à une approche plus descriptive de l’ordre de séries a-temporelles dont font état Gottschalk et Moffitt (1994). Ceci permet de présenter une analyse empirique pour les femmes aussi bien que pour les hommes et pour un échantillon plus large de travailleurs.Des prélèvements larges et étroits de données pour les hommes et les femmes séparément sont regroupés à l’intérieur de deux sous-périodes (1982–1989 et 1990–1997), en quatre groupes d’âge et pour six régions géographiques, ce qui donne 48 sous-échantillons. Dans chacun des cas ainsi constitué, on a calculé et analysé la variance totale des gains annuels des travailleurs et de leurs deux composantes (instabilité et inégalité des gains de longue période). Ces trois mesures de la variance sont retenues à titre de variables dépendantes dans les équations de régression, qui incluent des contrôles pour le glissement dans le temps entre les décennies et pour les différences d’âge et de région. Les différences dans le temps et par région permettent l’identification d’un taux de chômage distinct et l’évaluation des effets du taux de croissance du produit intérieur brut. Les résultats clés sont présentés dans les tableaux 4 à 6 et le tableau-résumé 2 du texte principal.Plusieurs conclusions se dégagent de l’étude. Premièrement, une simple constatation aussi bien qu’une analyse de régression indiquent un accroissement de la variabilité de l’ensemble des gains des travailleurs au passage d’une période à une autre, surtout chez les hommes. On a déjà fait de telles observations dans des études antérieures tant au Canada qu’aux États-Unis. Cependant, la majeure partie de l’accroissement dans la variabilité des gains, en particulier chez les hommes, pouvait être attribuée à l’ampleur croissante de l’inégalité des gains en longue période. Chez l’échantillon plus vaste des hommes sur le marché du travail, les augmentations de la variabilité des gains de longue période représentaient entre 59 et 134 pourcent de la variabilité la plus élevée des gains, alors que, dans l’échantillon des hommes occupant des emplois permanents, elles rendaient compte de presque toutes les augmentations. L’instabilité des gains accrue jouait effectivement un rôle secondaire dans l’ensemble de l’augmentation des gains des hommes. Par contre, chez les femmes, le changement était à peine perceptible ou encore, dans le cas d’un même groupe d’âge, il contribuait à réduire l’ensemble de la variabilité des gains. En bout de ligne, le décalage des variances de gains entre les femmes et les hommes s’est remarquablement estompé.Deuxièmement, tant les taux de chômage que les taux de croissance du produit intérieur brut exercent un impact statistiquement significatif sur la variabilité totale des gains et ses composantes. Là encore, le taux de chômage crée des effets plus prononcés quand on le considère en termes d’élasticité. Le profil de l’impact du taux de chômage et de celui de l’accroissement du PIB sur l’instabilité des gains corroborent les arguments conventionnels du jeu du marché du travail cyclique à l’effet que le chômage et l’instabilité des gains croissent au cours des récessions ou les périodes de croissance lente et entrent de nouveau dans un déclin au moment des détentes subséquentes associées à des marchés du travail plus serrés. Cependant, l’effet anticipé du taux croissance sur l’inégalité de gains en longue période ne cadre aucunement avec les raisonnements habituels. Il est plutôt compatible avec le paradigme alternatif qui veut que la croissance économique récente soit associée aux efforts de restructuration économique et de réaménagement des lieux de travail. Ces efforts se veulent une réponse aux changements dans la production des biens et aux changements technologiques liés à l’économie du savoir, au moment où ces mêmes changements contribuent à intensifier l’inégalité des gains sur le marché du travail. L’effet positif du taux de croissance apparaît plus prononcé chez les travailleurs dans des emplois permanents et moins chez ceux qui occupent une position marginale sur le marché du travail. Ceci nous amène à croire que la présente révision fédérale des normes du travail et de l’emploi du Code canadien du travail, pilotée par Harry Arthurs, devrait se pencher plus particulièrement sur les effets de la restructuration et des aménagements des lieux de travail sur les travailleurs, ceux qui occupent des emplois permanents et dont la situation crée un élargissement constant de l’inégalité au sein de la force de travail.Este documento examina la variabilidad de los ingresos de trabajadores en Canadá durante el periodo 1982-1997. Utilizando una amplia lista de ficheros de datos fiscales, descomponemos la variación total en los ingresos, entre trabajadores y a través del tiempo, en un componente de desigualdad de largo plazo entre trabajadores y un componente de inestabilidad del ingreso promedio de los trabajadores a lo largo del periodo. Encontramos un incremento en la variabilidad de los ingresos entre los periodos 1982-89 y 1990-97, esencialemente restringido a los hombres y principalmente ocasionado por la ampliación de la desigualdad de largo plazo en los ingresos. Segundo, la tendencia de la tasa de desempleo y los efectos de la creciente tasa de GDP sobre esos componentes de variación no son consistentes con las explicaciones convencionales y sugieren un paradigma alternativo para explicar cómo el crecimiento económico en ese periodo amplía la desigualdad de largo tiempo en los ingresos. Tercero, cuando la tasa de desempleo y los efectos de la creciente tasa de GDP son considerados conjuntamente, la mejora macroeconomica se revela como un reductor de la variabilidad general de los ingresos mientras que la reducción de la inestabilidad de los ingresos pesa más que la ampliación de la desigualdad de largo plazo en los ingresos

Meandering instability of curved step edges on growth of a crystalline cone

We study the meandering instability during growth of an isolated nanostructure, a crystalline cone, consisting of concentric circular steps. The onset of the instability is studied analytically within the framework of the standard Burton-Cabrera-Frank model, which is applied to describe step flow growth in circular geometry. We derive the correction to the most unstable wavelength and show that in general it depends on the curvature in a complicated way. Only in the asymptotic limit where the curvature approaches zero the results are shown to reduce to the rectangular case. The results obtained here are of importance in estimating growth regimes for stable nanostructures against step meandering.Comment: 4 pages, 3 figures, RevTe

Thermochromic display materials for use under wide variations in ambient illumination levels Annual progress report, 1 Dec. 1965 - 30 Nov. 1966

Thermochromic materials for use in display devices under wide ranges of ambient illuminatio