G_2^1 Affine Toda Field Theory: A Numerical Test of Exact S-Matrix results

We present the results of a Monte--Carlo simulation of the $G_2^{(1)}$ Affine Toda field theory action in two dimensions. We measured the ratio of the masses of the two fundamental particles as a function of the coupling constant. Our results strongly support the conjectured duality with the $D_4^{(3)}$ theory, and are consistent with the mass formula of Delius et al.Comment: 5 pages, LaTeX, DTP-9223, DAMTP-92-4

Evaluating the Effectiveness of Shielding Material, Vehicle Shape and Astronaut Position for Deep Space Travel

Background: As future crewed, deep space missions are being planned, it is important to assess how spacecraft design can be used to minimize radiation exposure. Collectively with shielding material, vehicle shape and astronaut position must be used to protect astronauts from the two primary sources of space radiation: Galactic Cosmic Rays (GCRs) and Solar Particle Events (SPEs). Methods: The On-Line Tool for the Assessment of Radiation in Space (OLTARIS) version 4.1 analysis package is used to evaluate and analyze this detailed radiation field. Developed by the National Aeronautics and Space Administration\u27s (NASA) Langley Research Center, the tool enables engineering and research related space radiation calculations. Each configuration is evaluated in whole body effective dose equivalent (ED). This research evaluates 70 aerospace materials, 2 vehicle shapes and 3 astronaut positions. Results and Conclusions: The material analyses show that for metals, aluminum outperforms and therefore is the most feasible metal for deep space travel. But when evaluating all materials, polyethylene outperforms all feasible aerospace materials. The vehicle shape and astronaut position analyses show that moving a human phantom closer to a wall does significantly decrease the ED. This pattern is not dependent on material nor boundary condition, but the mean shielding thickness a source ray must travel through for the GCR boundary condition. For shielding thicknesses greater than 30 g/cm 2 for polyethylene and 100g/cm 2 for aluminum, the results suggest that having astronauts’ habitats and work areas located further from the center will help protect astronauts longer from deep space radiation.https://scholarscompass.vcu.edu/gradposters/1067/thumbnail.jp

On Charge-3 Cyclic Monopoles

We determine the spectral curve of charge 3 BPS su(2) monopoles with C_3 cyclic symmetry. The symmetry means that the genus 4 spectral curve covers a (Toda) spectral curve of genus 2. A well adapted homology basis is presented enabling the theta functions and monopole data of the genus 4 curve to be given in terms of genus 2 data. The Richelot correspondence, a generalization of the arithmetic mean, is used to solve for this genus 2 curve. Results of other approaches are compared.Comment: 34 pages, 16 figures. Revision: Abstract added and a few small change

Optimal Length of Moving Averages to Use When Forecasting Basis

The previous year's basis and 2 to 5-year historical moving averages were used to forecast preharvest and end of storage period basis for hard wheat, soft wheat, corn, and soybeans. Forecast accuracy was compared within a mixed model, to result in each forecasts mean absolute error. The forecast which produced the minimum mean absolute error provided the optimal forecast. In general, forecasts containing less historical information resulted in optimal basis forecasts. Only the preharvest hard wheat forecasts benefited from longer moving averages. The previous year's basis provided the optimal forecast when considering all crops, periods, and locations. The general rule of thumb resulting from this study is that at locations or during times not likely to undergo structural change, longer moving averages provide the best forecasts, but following a structural change, the previous year's basis provides the optimal forecast.Department of Agricultural Economic

Moose Management in Southwest Montana: Insights From Four Years of Field Research

From 2007-2010, Montana Fish, Wildlife and Parks conducted research on moose ecology on the Mount Haggin Wildlife Management Area in southwestern Montana. In this presentation, we will briefly review our methodology and results, but will largely focus on the management implications of this research and potential ideas for future research. The goals of this research were to determine the habitat selection of cow moose during winter with an emphasis on willow community importance and to examine population-scale willow browse utilization through browse patterns. We also sought to contribute to a foundation for future research on moose in Montana. Using browse surveys on willow (Salix spp.) and GPS collars on cow moose, we were able to determine the current intensity of willow browse and basic habitat use of cow moose (e.g. home range size and location), and to model variables associated with both browse utilization and habitat selection. Management implications of the browse surveys include suggestions regarding sample sizes and sample site placement for future monitoring of willow community health or browse utilization. Additionally, species preference by moose has implications for riparian restoration. The habitat selection analysis showed the importance of willow and conifer communities and has implications for habitat conservation and aerial survey methods. Future research on moose ecology in Montana should focus on the impact of changing habitat and climate on habitat selection and population dynamics, the role of predation on populations of moose, and improving aerial or other survey techniques to more accurately monitor moose population trends

Winter Ecology Of The Shiras Moose On The Mount Haggin Wildlife Management Area

Moose (Alces alces shirasi) populations across Montana have expanded in the last century, both in geographic range and in population size. This expansion has had a negative impact on moose winter range in some locations where moose have overutilized key browse species. Excessive and unsustainable browsing has the potential to reduce local biodiversity and carrying capacity of moose and other ungulates. The browse species of interest in this study were willow (Salix spp), a highly palatable and abundant browse source for moose on many winter ranges, including our study area in southwestern Montana. The objectives of this study were to determine patterns of willow community use by selected female moose during winter and to quantify willow utilization across the study area to examine population scale habitat use through browse patterns. To accomplish these objectives we deployed GPS collars on 18 cow moose, 6 each in the winters of 2007, 2008, and 2009-2010. We also completed large scale, systematic browse surveys in the springs of 2008, 2009 and 2010. Results indicated cow moose spent the plurality of the winter within willow communities (48.4%, 48.2%, 51.8%, and 49.8% of locations in the winters of 2007, 2008, 2009, and 2010, respectively), but the estimated percentage of browsed willow twigs across the study area was low (11.5%, 8.0%, and 8.3% in 2008, 2009, and 2010, respectively). Our data suggest that while moose have the potential to significantly impact willow communities, this did not appear to be the case on the Mount Haggin WMA at current moose densities

Using Coupled Eulerian and Lagrangian Grids to Model Explosive Interactions with Buildings

This paper presents the development of a computational model that can be used to study the interactions between structures and detonating explosives contained within them. This model was developed as part of an effort to develop a rubble characterization model for use in AmmoSIM, an agent based urban tactical decision aid (UTDA) software for weapon-target pairing. The rubble pile created following the collapse of a building in a combat situation can significantly impact mission accomplishment, particularly in the area of movement and maneuver. The information provided by AmmoSIM will enable both platoon level and command center staff to make informed decisions concerning urban attack tactics. Computational models were created using a combination of AUTODYN 2D and 3D. The detonation was modeled using a 2D wedge, which is a common method used in AUTODYN. The information obtained from the wedge calculation was then written to a data file and subsequently remapped into a larger 3D Euler air grid. The air grid loaded with blast pressure information was coupled to interact with the Lagrangian building parts. The Riedel, Hiermaier and Thoma (RHT) Concrete Model from the AUTODYN material library was utilized to create the components of the building. Results of the latest models will be given. Additionally, the paper details the development of the model at length including topics such as grid sizing, computational cost comparisons, grid interactions, multi-solver coupling, strain erosion, and material parameters and selections

The effects of nocturnal hemodialysis compared to conventional hemodialysis on change in left ventricular mass: Rationale and study design of a randomized controlled pilot study

BACKGROUND: Nocturnal hemodialysis (NHD) is an alternative to conventional three times per week hemodialysis (CvHD) and has been reported to improve several health outcomes. To date, no randomized controlled trial (RCT) has compared NHD and CvHD. We have undertaken a multi-center RCT in hemodialysis patients comparing the effect of NHD to CvHD on left ventricular (LV) mass, as measured by cardiac magnetic resonance imaging (cMR). METHODOLOGY/DESIGN: All patients in Alberta, Canada, expressing an interest in performing NHD are eligible for the study. Patients enrolled in the study will be randomized to either NHD or CvHD for a six month period. All patients will have a full clinical assessment, including collection of biochemical and cMR data at baseline and at 6 months. Both groups of patients will be monitored biweekly to optimize blood pressure (BP) to a goal of <130/80 mmHg post-dialysis using a predefined BP management protocol. The primary outcome is change in LV mass, a surrogate marker for cardiac mortality, measured at baseline and 6 months. The high sensitivity and reproducibility of cMR facilitates reduction of the required sample size and the time needed between measures compared with echocardiography. Secondary outcomes include BP control, anemia, mineral metabolism, health-related quality of life, and costs. DISCUSSION: To our knowledge, this study will be the first RCT evaluating health outcomes in NHD. The impact of NHD on LV mass represents a clinically important outcome which will further elucidate the potential benefits of NHD and guide future clinical endpoint studies

Scalable Scheduling Policy Design for Open Soft Real-Time Systems

Open soft real-time systems, such as mobile robots, must respond adaptively to varying operating conditions, while balancing the need to perform multiple mission specific tasks against the requirement that those tasks complete in a timely manner. Setting and enforcing a utilization target for shared resources is a key mechanism for achieving this behavior. However, because of the uncertainty and non-preemptability of some tasks, key assumptions of classical scheduling approaches do not hold. In previous work we presented foundational methods for generating task scheduling policies to enforce proportional resource utilization for open soft real-time systems with these properties. However, these methods scale exponentially in the number of tasks, limiting their practical applicability. In this paper, we present a novel parameterized scheduling policy that scales our technique to a much wider range of systems. These policies can represent geometric features of the scheduling policies produced by our earlier methods, but only require a number of parameters that is quadratic in the number of tasks. We provide empirical evidence that the best of these policies are competitive with exact solution methods in small problems, and significantly outperform heuristic methods in larger ones