Three-Body Capture of Irregular Satellites: Application to Jupiter

We investigate a new theory of the origin of the irregular satellites of the giant planets: capture of one member of a ~100-km binary asteroid after tidal disruption. The energy loss from disruption is sufficient for capture, but it cannot deliver the bodies directly to the observed orbits of the irregular satellites. Instead, the long-lived capture orbits subsequently evolve inward due to interactions with a tenuous circumplanetary gas disk. We focus on the capture by Jupiter, which, due to its large mass, provides the most stringent test of our model. We investigate the possible fates of disrupted bodies, the differences between prograde and retrograde captures, and the effects of Callisto on captured objects. We make an impulse approximation and discuss how it allows us to generalize capture results from equal-mass binaries to binaries with arbitrary mass ratios. We find that at Jupiter, binaries offer an increase of a factor of ~10 in the capture rate of 100-km objects as compared to single bodies, for objects separated by tens of radii that approach the planet on relatively low-energy trajectories. These bodies are at risk of collision with Callisto, but may be preserved by gas drag if their pericenters are raised quickly enough. We conclude that our mechanism is as capable of producing large irregular satellites as previous suggestions, and it avoids several problems faced by alternative models.Comment: 39 pages, 12 figures, 1 table, submitted to Icaru

A review of periodical literature on merit rating.

Thesis (Ed.M.)--Boston Universit

SPATIAL AND SUPPLY/DEMAND AGGLOMERATION ECONOMIES: AN EVALUATION OF STATE-AND-INDUSTRY-LINKAGES IN THE U.S. FOOD SYSTEM

In this paper we postulate, measure, and evaluate the importance of cost-impacts from spatial and industrial spillovers for analysis of economic performance. To accomplish this, we incorporate measures of "activity levels" of related states and industries in a cost function model, and estimate their associated thick market and agglomeration effects in terms of shadow values and elasticities. We focus on the food processing sector, the proximity of own-industry activity in neighboring states, and the supply- and demand- side "drivers", associated with urbanization and localization economies (represented by the GSP and agricultural intensity in the own and neighboring states). We find significant cost-savings benefits to a states food processing sector of being close to other food manufacturing centers (high levels of food processing activity in neighboring states). We also find it beneficial to be in a state with high purchasing power (demand), and to have neighboring states that are agriculture-based (supply). However, it also seems costly to actually be located in a heavily agricultural or rural state, possibly due to diseconomies from "thin markets" associated with infrastructure support and labor markets.Productivity Analysis,

Reply to the comment by Carmelo Anile on the paper "Complexity analysis of the cerebrospinal fluid pulse waveform during infusion studies"

Veterinary technology is an emerging profession within the veterinary and allied animal health fields in Australia and affords graduates the opportunity to contribute to the small but growing body of literature within this discipline. This study describes the introduction of a contextualised assessment task to develop students’ research capability, competence and confidence in professional writing, and to engage them with the academic publishing process. Students worked in self-selected dyads to author a scientific case report, of publishable standard, based on authentic cases from their clinical practicum. Intrinsic to the task, students attended a series of workshops that explored topics such as critiquing the literature, professional writing styles and oral presentation skills. Assessment was multi-staged with progressive feedback, including peer review, and culminated with students presenting their abstracts at a mock conference. Students reported the task to be an enjoyable and valuable learning experience which improved their competence and confidence in scientific writing; supported by a comparison of previously submitted work. Linking scientific writing skills to clinical practice experiences enhanced learning outcomes and may foster the professionalisation of students within this emerging discipline

The knowledge, the will and the power : a plan of action to meet the HIV prevention needs of Africans living in England

The Knowledge, The Will and The Power is a statement of what we, the NAHIP Partners, plan to do to prevent HIV transmissions occurring during sexual activity among the diverse population of Africans living in England (Chapter 1). We describe the size and context of Africans living in England (Chapter 2), the size of the HIV epidemic and the number of new infections occurring (Chapter 3), as well as the behaviours and facilitators of new infections (Chapter 4). We then articulate how the NAHIP partners intend to influence future behaviours (Chapter 5). The final three chapters describe what is required in order to meet the HIV prevention needs of individual African people (Chapter 6), of NAHIP partner organisations (Chapter 7) and of those undertaking decisions related to policy, planning and research (Chapter 8)