The stability of a trailing-line vortex in compressible flow

We consider the inviscid stability of the Batchelor (1964) vortex in a compressible flow. The problem is tackled numerically and also asymptotically, in the limit of large (aximuthal and streamwise) wavenumbers, together with large Mach numbers. The nature of the solution passes through different regimes as the Mach number increases, relative to the wavenumbers. At very high wavenumbers and Mach numbers, the mode which is present in the incompressible case ceases to be unstable, while new 'center mode' forms, whose stability characteristics, are determined primarily by conditions close to the vortex axis. We find that generally the flow becomes less unstable as the Mach number increases, and that the regime of instability appears generally confined to disturbances in a direction counter to the direction of the rotation of the swirl of the vortex. Throughout the paper, comparison is made between our numerical results and results obtained from the various asymptotic theories

The evolutionary sequence of post-starburst galaxies

© 2017 The Authors. There are multiple ways in which to select post-starburst galaxies in the literature. In this work, we present a study into how two well-used selection techniques have consequences on observable post-starburst galaxy parameters, such as colour, morphology and environment, and how this affects interpretations of their role in the galaxy duty cycle. We identify a master sample of Hδ strong (EWHδ> 3Å) post-starburst galaxies from the value-added catalogue in the seventh data release of the Sloan Digital Sky Survey (SDSS DR7) over a redshift range 0.01 -2.5Å) but one having an additional cut onEWHα (> -3Å).We examine the differences in observables and AGN fractions to see what effect the Hα cut has on the properties of post-starburst galaxies and what these differing samples can tell us about the duty cycle of post-starburst galaxies. We find that Hδ strong galaxies peak in the 'blue cloud', E+As in the 'green valley' and pure E+As in the 'red sequence'.We also find that pure E+As have a more early-type morphology and a higher fraction in denser environments compared with the Hδ strong and E+A galaxies. These results suggest that there is an evolutionary sequence in the post-starburst phase from blue discy galaxies with residual star formation to passive red early-types

The Relational Worlds of a Child with a Significant Disability

This dissertation explores the relational worlds of a single child with a significant disability. Previous research on relationships for individuals with significant disabilities has heavily relied on the perceptions of and information from others, rather than the individual with a disability him or herself. This research is an ethnographic exploration of a single child with a disability, Julia, and the dynamic ecosystem of her relational worlds. The affect and behaviors of this child were explored in the school setting. The findings revealed that friendships\u27 were present for Julia, and that they resulted in expressions of enjoyment and happiness. These friendships, however, were found to be inconsistent with more typical manifestations of this relationship type, and were far fewer in number than other types of engagement, including solitary, fringe, unilateral and other mutual forms of engagement. The findings also suggested that, while aspects of Julia\u27s cognition, communication and experience contributed to the kinds and qualities of relationships, the larger ecology of her relational worlds were also of significant impact to relationship formation. The findings of this study support that for positive relationships to develop, and for the maximal growth and satisfaction of individuals with significant disabilities, greater attention must be given to not only how the individual uniquely responds to and benefits from relationships, but also how the ecosystem of relational worlds can be better understood and altered so as to accommodate opportunities for and the growth of relationships for the individual

Lamb marking

LAMB marking is the most severe of the various ordeals which sheep are called upon to endure during their lifetimes—yet it is an operation, or rather a series of operations, to which the average fiockowner gives but little care and thought

Fleece measurements in selecting merino sheep.

During recent months a number of well-attended fleece measurement demonstrations have been held in various districts. The object of the demonstrations was to make studbreeders familiar with the technique under shearing-shed conditions and, during discussion, gain a clearer understanding of fleece measurement and its application to stud-breeding. From a small group of sheep, the stud-breeders selected those they considered carried the heaviest and lightest fleeces. The whole group was then shorn and the fleeces weighed, classed and valued. The demonstrations have shown definitely that selecting for fleece weight by eye and touch is inefficient compared with the scales

Measures of readiness for cognitive behavioural therapy in people with intellectual disability: A systematic review

BACKGROUND AND AIMS: Cognitive behavioural therapy (CBT) is a promising treatment for mental health problems in people with intellectual disabilities but some may not be suited or ready. This review critically evaluates the quality and utility of measures of CBT readiness in people with intellectual disabilities. METHODS AND PROCEDURES: Twelve studies of six measures based on three aspects of CBT readiness were identified through systematic review. OUTCOMES AND RESULTS: Across measures, measurement quality was largely poor or un-assessed. Only one study evaluated measurement change over the course of CBT. Not all participants with intellectual disabilities could ‘pass’ readiness measures and performance may be affected by levels of language and cognitive functioning. There was some evidence that CBT readiness is trainable with brief interventions. CONCLUSIONS AND IMPLICATIONS: Before using readiness measures in a clinical context, further work is needed to extend initial evidence on recognising cognitive mediation as a CBT readiness ability. Given the lack of consensus as to the definition of CBT readiness and the heterogeneity of CBT interventions, future research could also focus on developing readiness measures using a bottom up approach, developing measures within the context of CBT interventions themselves, before further refining and establishing their psychometric properties. WHAT THIS PAPER ADDS: This paper is the first to systematically review measures of skills thought necessary to be ready for cognitive behavioural therapy in intellectual disabilities. The findings suggest that while readiness skills may be trainable with brief interventions, the available measures of these skills have not been fully evaluated for quality. Levels of functioning on these measures have yet to be established relative to those without intellectual disabilities and critically, there is very little evidence as to whether these skills are important in cognitive behavioural therapy process and outcome. We suggest that future research could focus on those constructs where there is preliminary evidence for utility such as recognising cognitive mediation and also on developing the concept of readiness perhaps by developing measures within the context of specific CBT interventions. Until this is done, clinicians should exercise caution in using these measures to assess readiness for cognitive behavioural therapy in people with intellectual disabilities