The Likelihood Ratio as a tool for Radio Continuum Surveys with SKA precursor telescopes

In this paper we investigate the performance of the likelihood ratio method as a tool for identifying optical and infrared counterparts to proposed radio continuum surveys with SKA precursor and pathfinder telescopes. We present a comparison of the infrared counterparts identified by the likelihood ratio in the VISTA Deep Extragalactic Observations (VIDEO) survey to radio observations with 6, 10 and 15 arcsec resolution. We cross-match a deep radio catalogue consisting of radio sources with peak flux density $>$ 60 $\mu$Jy with deep near-infrared data limited to $K_{\mathrm{s}}\lesssim$ 22.6. Comparing the infrared counterparts from this procedure to those obtained when cross-matching a set of simulated lower resolution radio catalogues indicates that degrading the resolution from 6 arcsec to 10 and 15 arcsec decreases the completeness of the cross-matched catalogue by approximately 3 and 7 percent respectively. When matching against shallower infrared data, comparable to that achieved by the VISTA Hemisphere Survey, the fraction of radio sources with reliably identified counterparts drops from $\sim$89%, at $K_{\mathrm{s}}\lesssim$22.6, to 47% with $K_{\mathrm{s}}\lesssim$20.0. Decreasing the resolution at this shallower infrared limit does not result in any further decrease in the completeness produced by the likelihood ratio matching procedure. However, we note that radio continuum surveys with the MeerKAT and eventually the SKA, will require long baselines in order to ensure that the resulting maps are not limited by instrumental confusion noise.Comment: 10 pages, 7 figures, accepted for publication in mnra

Perceptual adaptation by normally hearing listeners to a simulated "hole" in hearing

Simulations of cochlear implants have demonstrated that the deleterious effects of a frequency misalignment between analysis bands and characteristic frequencies at basally shifted simulated electrode locations are significantly reduced with training. However, a distortion of frequency-to-place mapping may also arise due to a region of dysfunctional neurons that creates a "hole" in the tonotopic representation. This study simulated a 10 mm hole in the mid-frequency region. Noise-band processors were created with six output bands (three apical and three basal to the hole). The spectral information that would have been represented in the hole was either dropped or reassigned to bands on either side. Such reassignment preserves information but warps the place code, which may in itself impair performance. Normally hearing subjects received three hours of training in two reassignment conditions. Speech recognition improved considerably with training. Scores were much lower in a baseline (untrained) condition where information from the hole region was dropped. A second group of subjects trained in this dropped condition did show some improvement; however, scores after training were significantly lower than in the reassignment conditions. These results are consistent with the view that speech processors should present the most informative frequency range irrespective of frequency misalignment. 0 2006 Acoustical Society of America

The effect of gap size on growth and species composition of 15-year-old regrowth in mixed blackbutt forests

In north-eastern New South Wales (NSW) the Regional Forest Agreement process has transferred more than 400 000 ha of state forests to national park, and restricted silviculture to 'single tree selection' and a light form of 'Australian group selection'. While these silvicultural systems are theoretically well suited to ecologically sustainable forest management, there is concern that in their current form they are not achieving adequate regeneration or optimising the growth of that regeneration. This is of particular concern for mixed-species blackbutt forest, for which there is no quantitative research concerning the growth and composition of regeneration within group - selection gaps. We address this issue by: (1) quantifying the effect of gap size, and other gap characteristics including distance from gap edge, on the growth of regeneration; and (2) assessing the effect of gap size on the composition of regeneration. We use the answers to these questions to recommend a gap size for group selection silviculture in mixed-species blackbutt forests in north-eastern NSW. We measured attributes describing the growth and composition of regeneration in nine circular group-selection gaps in mixedspecies blackbutt forest near Coffs Harbour and Wauchope. These gaps contained 14.5-15.5-y-old regeneration and provided three replicates of small (0.27-0.3 ha), medium (0.45-0.67 ha) and large (0.93-0.97 ha) gaps. ANOVA testing indicated significantly (P < 0.05) lower height, diameter and volume growth of dominant blackbutt stems up to five metres from gap edge. Outside this zone growth remained fairly constant, indicating dominant blackbutt trees were susceptible to suppression only in close proximity to gap edges. Multiple regression analysis confirmed the relatively short distance from gap edges over which suppression occurred, with distance to closest gap edge explaining a small proportion of the variation in the models fitted for tree- and plot-level growth. The origin of blackbutt regeneration within gaps was a significant effect in tree-level growth models, with planted stems having increased diameter and volume growth compared with stems regenerated from natural seedfall. Gap size had no significant effect on the composition of regeneration. We conclude that for the range of gaps tested, 1 -ha gaps are optimal for growth because they minimise the proportion of gap within 5 m of the retained forest edge, without altering composition. Larger gaps have also been shown to have operational and economic benefits compared with smaller gaps

Validation of evidence-Based Fall Prevention Programs for adults with intellectual and/or developmental disorders: a modified otago exercise Program

Introduction: Evidence-based fall prevention (EBFP) programs significantly decrease fall risk, falls, and fall-related injuries in community-dwelling older adults. To date, EBFP programs are only validated for use among people with normal cognition and, therefore, are not evidence-based for adults with intellectual and/or developmental disorders (IDD) such as Alzheimer’s disease and related dementias, cerebral vascular accident, or traumatic brain injury. Background: Adults with IDD experience not only a higher rate of falls than their community-dwelling, cognitively intact peers but also higher rates and earlier onset of chronic diseases, also known to increase fall risk. Adults with IDD experience many barriers to health care and health promotion programs. As the lifespan for people with IDD continues to increase, issues of aging (including falls with associated injury) are on the rise and require effective and efficient prevention. Methods: A modified group-based version of the Otago Exercise Program (OEP) was developed and implemented at a worksite employing adults with IDD in Montana. Participants were tested pre- and post-intervention using the Center for Disease Control and Prevention’s (CDC) Stopping Elderly Accidents Deaths and Injuries (STEADI) tool kit. Participants participated in progressive once weekly, 1-h group exercise classes and home programs over a 7-week period. Discharge planning with consumers and caregivers included home exercise, walking, and an optional home assessment. Results: Despite the limited number of participants (n = 15) and short length of participation, improvements were observed in the 30-s Chair Stand Test, 4-Stage Balance Test, and 2-Minute Walk Test. Additionally, three individuals experienced an improvement in ambulation independence. Participants reported no falls during the study period. Discussion: Promising results of this preliminary project underline the need for further study of this modified OEP among adults with IDD. Future multicenter study should include more participants in diverse geographic regions with longer lengths of participation and follow-up