The Radial Distribution of the Kuiper Belt

We examine the radial distribution of the Kuiper Belt objects (KBOs) using a method that is insensitive to observational bias effects. This technique allows the use of the discovery distances of all KBOs, independent of orbital classification or discovery circumstance. We verify the presence of an outer edge to the Kuiper Belt, as reported in other works, and we measure this edge to be at R = 47 ± 1 AU given any physically plausible model of the size distribution. We confirm that this outer edge is due to the classical KBOs, the most numerically dominant observationally. In addition, we find that current surveys do not preclude the presence of a second, unobserved Kuiper Belt beyond R = 76 AU

Discovery of a Candidate Inner Oort Cloud Planetoid

We report the discovery of the minor planet (90377) Sedna, the most distant object ever seen in the solar system. Prediscovery images from 2001, 2002, and 2003 have allowed us to refine the orbit sufficiently to conclude that Sedna is on a highly eccentric orbit that permanently resides well beyond the Kuiper Belt with a semimajor axis of 480 ± 40 AU and a perihelion of 76 ± 4 AU. Such an orbit is unexpected in our current understanding of the solar system but could be the result of scattering by a yet-to-be-discovered planet, perturbation by an anomalously close stellar encounter, or formation of the solar system within a cluster of stars. In all of these cases a significant additional population is likely present, and in the two most likely cases Sedna is best considered a member of the inner Oort Cloud, which then extends to much smaller semimajor axes than previously expected. Continued discovery and orbital characterization of objects in this inner Oort Cloud will verify the genesis of this unexpected population

Making Malice Musical: Verdi’s Compositional Journey Through the Eyes of Six Villains

Giuseppe Verdi is a pillar of the operatic world and had a profound impact on the evolution of the art form. From a rudimentary beginning, he developed over time from a popular creator of operas in the solita forma style of 19th century Italy into a master craftsman of combining music, text, and theatrical drama. Verdi utilized the popular compositional formal convention of solita forma to begin his career. Over time he evolved beyond its boundaries and shifted his focus to the holistic theatrical presentation of the drama. Much has been written about this evolution through analysis of Verdi’s most famous operas and their arias. This paper instead focuses on the arias of six villains, and through those arias, examines Verdi’s evolution from solita forma to the through–composed, free style he adopted near the end of his life. His desire to provide theatrically suitable accompaniment for the malicious intentions and actions of his villains, and his need to tell a complete theatrical musical story, both influenced his choices in compositional form and led him eventually to leave solita forma behind entirely

A Correlation Between Inclination and Color in the Classical Kuiper Belt

We have measured broadband optical BVR photometry of 24 Classical and Scattered Kuiper belt objects (KBOs), approximately doubling the published sample of colors for these classes of objects. We find a statistically significant correlation between object color and inclination in the Classical Kuiper belt using our data. The color and inclination correlation increases in significance after the inclusion of additional data points culled from all published works. Apparently, this color and inclination correlation has not been more widely reported because the Plutinos show no such correlation, and thus have been a major contaminant in previous samples. The color and inclination correlation excludes simple origins of color diversity, such as the presence of a coloring agent without regard to dynamical effects. Unfortunately, our current knowledge of the Kuiper belt precludes us from understanding whether the color and inclination trend is due to environmental factors, such as collisional resurfacing, or primordial population effects. A perihelion and color correlation is also evident, although this appears to be a spurious correlation induced by sampling bias, as perihelion and inclination are correlated in the observed sample of KBOs.Comment: Accepted to Astrophysical Journal Letter

Benefits to Australia from ACIAR-funded Research

Research and Development/Tech Change/Emerging Technologies,

Low yield of unselected testing in patients with acutely abnormal liver function tests.

OBJECTIVES: To audit the diagnostic yield and cost implications of the use of a 'liver screen' for inpatients with abnormal liver function tests. DESIGN: We performed a retrospective audit of inpatients with abnormal liver function tests. We analysed all investigations ordered including biochemistry, immunology, virology and radiology. The final diagnosis was ascertained in each case, and the diagnostic yield and cost per positive diagnosis for each investigation were calculated. SETTING: St Thomas' NHS Trust. PARTICIPANTS: All inpatients investigated for abnormal liver function tests over a 12-month period. MAIN OUTCOME MEASURES: We calculated the percentage of courses due to each diagnosis, the yield of each investigation and the cost per positive diagnosis for each investigation. RESULTS: A total of 308 patients were included, and a final diagnosis was made in 224 patients (73%) on the basis of both clinical data and investigations. There was considerable heterogeneity in the tests included in an acute liver screen. History and ultrasound yielded the most diagnoses (40% and 30%, respectively). The yield of autoimmune and metabolic screens was minimal. CONCLUSIONS: Our results demonstrate the low yield of unselected testing in patients with abnormal liver function tests. A thorough history, ultrasound and testing for blood-borne viruses are the cornerstones of diagnosis. Specialist input should be sought before further testing. Prospective studies to evaluate the yield and cost-effectiveness of different testing strategies are needed

Effects of Nitrogen Deposition and Flow Permanence on Stream Organic Matter Dynamics

The objective of this study was to investigate the effects of N enrichment and flow permanence on stream organic matter dynamics at the Bear Brook Watershed in Maine (BBWM). BBWM is a paired-catchment manipulation of atmospheric (NH4)2SO4 deposition, and the goal of the experiment is to understand how increased N affects forested catchments. The treatment has increased stream nitrate and foliar N concentrations in the treatment watershed. Because streams draining BBWM are intermittent, this investigation provided an opportunity to investigate the combined effects of stream flow permanence and human alteration of N cycling in a forested watershed. Several lines of evidence suggested that stream drying affects streams more than N deposition. For leaf-litter processing, elevated dissolved N concentrations played a minimal role in regulating stream leaf-litter processing. Increased foliar N, however, did influence detritus processing by increasing microbial activity, and possibly increasing detritivore biomass. Based on these findings, I concluded that physical similarities between streams regulated leaf litter loss rates. For stream organic matter dynamics, BBWM did not have different inputs or storage, and only modest differences in export of coarse organic matter. These results support the conclusion that N additions at BBWM do not affect these streams, and that physical characteristics regulate what happens to organic matter. Utilization of organic matter, measured as invertebrate secondary production, was also the same between streams, but varied temporally. Increased production in the second year was attributed to increased stream permanence and organic matter biomass. These results again suggest that N deposition at BBWM has little effect on organic matter dynamics, specifically utilization. Differences in drying for streams did affect production and invertebrate assemblage structure. To further assess stream drying effects, secondary production was quantified in 6 reaches with differing drying regimes. Production ranged from 1.7 to 2.9 g AFDM m-2 yr-1 among all reaches, and flow permanence and organic matter biomass appeared to influence these patterns. This work suggests that chemical changes in streams because of atmospheric N deposition are less important than gradients in flow permanence in regulating organic matter in intermittent streams