Purpose: This study examined the effectiveness of two differing interventions to improve the consonant cluster production in six children aged 4-5 years with concomitant speech sound disorder and expressive language difficulty. Method: Participants were selected for the study based on a high incidence of consonant clusters errors in their speech production. All participants had at least 75% of their cluster production attempts in error in their initial speech sample. The participants were randomly assigned to receive 24 hours of either a phonological awareness intervention with integrated speech targets (Gillon & Moriarty, 2005), or a morphosyntax intervention which alternated therapy sessions for language and speech targets (Haskill, Tyler, & Tolbert, 2001) Each intervention was administered in two blocks of 6 weeks separated by a 6-week therapy break. Hour-long small group intervention sessions were attended twice weekly by all participants. Consonant cluster productions were assessed using speech probes and standardised speech assessments. These were administered pre-intervention, post-intervention, and at follow-up 3 months post-intervention. These measures were compared to identify any improvement in (a) word-initial cluster accuracy as a result of /s/ clusters being targeted in the phonological awareness intervention;(b) word-final cluster accuracy as a result of word-final morphemes being targeted in the morphosyntax intervention; and (c) cluster element accuracy as a result of improved production of the phonemes as singletons. Results: The data supported the hypotheses that targeting word-initial clusters in the phonological awareness intervention would lead to improvements in accuracy for target /s/ clusters, non-target /s/ clusters and singleton fricatives. Improvements in production of /s/ clusters, singleton fricatives, and untreated consonant + liquid clusters were significant for all participants in this intervention type. The improvement for word initial /s/ clusters was greater than for the treatment group who received morphosyntax intervention. The data was less convincing for the hypothesis that word-final cluster production would improve following intervention for word-final morphemes in the morphosyntax intervention. Although there was improvement in word-final production for two of the participants in this group, there were similar or greater improvements seen for the children who received phonological awareness intervention in which word-final clusters were not targeted. The data supported the final hypothesis that improved production of singletons following speech intervention for these phonemes would result in improved accuracy for the phonemes when attempted in the context of clusters. All participants had improved accuracy of cluster elements that had been singleton targets during intervention. Conclusion: The data showed that the Phonological Awareness intervention led to significant improvement in production of the target /s/ clusters, and generalised to increased accuracy for production of singleton fricatives, non-target /s/ clusters, and untreated consonant + liquid clusters. The Morphosyntax intervention resulted in less consistent improvement in production for target word-final clusters. In this programme, word-final clusters were implicitly treated through language intervention for word-final morphemes. The data indicates that improvement in consonant cluster production is facilitated when using explicit teaching methods to introduce and practice consonant clusters during intervention with children with speech sound disorder.

The relationship first pointed out by Tully and Fisher between the luminosity of spiral galaxies and their maximum rotation velocity, as measured by the 21 cm line-width, continues to be one of the best methods available to measure relative distances. At infrared wavelengths, the observational scatter about this relation is typically 0.35 to 0.50 magnitudes, permitting relative distance estimates with an accuracy of about 20 percent. The Malmquist bias in a magnitude-limited sample is 1.38σ ², and while the solution to the general problem is complex, it is clear that reducing the scatter about the Tully-Fisher relation by even a factor of two would make a large difference in our ability to determine the local velocity field from distances and velocities of individual galaxies. In this dissertation we discuss the scatter in the Tully-Fisher relation at infrared wavelengths, and look for ways to reduce that dispersion through the inclusion of additional observational parameters. The data for this study are derived from a CCD survey of 244 spiral galaxies in twenty clusters falling in the redshift range 3,000 to 11,000 km s⁻¹. From surface brightness profiles and elliptical aperture photometry, we obtained isophotal and total magnitudes at B, R, and I, isophotal diameters, mean and nuclear surface brightnesses, and a concentration parameter indicative of the bulge-to-disk ratio. These quantities were then combined with colors and HI-content measures taken from the literature in a search for correlations with Tully-Fisher residuals. None of the trial second-parameters resulted in a substantial decrease in the scatter about the fiducial Tully-Fisher relation. An examination of the properties of the cluster samples shows that many of the clusters exhibit considerable substructure. While it is possible that the implied depth effects are important to the scatter about the magnitude/line-width relation, calculated lower limits to the dispersion in depth turn out to be rather small.

Indirect searches for planets (such as radial velocity studies)show that their formation may be quite common. The planets are however too small and faint to be seen against the glare of their host stars; therefore, their direct detectionis limited to the nearest systems. Alternatively one can study planets by studying their "by-product" -- dust. We see raw material available for planets around young stars, anddebris dust around old stars betraying planet-induced activity. Dust has a larger surface area per unit mass compared with a large body; it can be spread over a largersolid angle, intercepting more starlight and emitting much more lightvia reprocessing. By studying dusty disks we can infer the presence of planets at larger distances.Here we present results of a survey conducted with the SpitzerSpace Telescope of debrisdisks in three open clusters. With ages of 30--100 Myrs, these clusters are old enough that the primordialdust should have accreted into planetesimals, fallen onto the star, or been blown away due to a numberof physical processes. The dust we observe must come from collisions or sublimation of larger bodies.The purpose of this study is to investigate the dustevolution in the terrestrial planet zone, analogous to the Zodiacal cloud in our Solar system. We are most sensitive to this zone becausethe peak of a 125 K black body radiation falls into the primary pass-band of our survey -- 24 micron. We investigate the fraction and amount of the infra-red excesses around intermediate- to solar-mass stars in open stellar clusterswith well defined ages. The results are analyzed in the context of disk studies at other wavelengths and ages, providing an understanding of the time-scale for diskdissipation and ultimately planet building and frequency.

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