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

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

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

HETEROGENEITY AND POWER TO DETECT TRENDS IN MOOSE BROWSE UTILIZATION OF WILLOW COMMUNITIES

Monitoring of browse utilization of plant communities is consistently recommended as an important component of monitoring moose (Alces alces) populations across regions. We monitored winter browse utilization by moose within a willow (Salix spp.) -dominated winter range of Montana in 2008–2010. We sought to improve our understanding of: 1) spatiotemporal heterogeneity of intensity of moose browsing across the winter range, 2) species-specific selection of willow by moose during winter, and 3) appropriate sample sizes, placement, and stratification of monitoring sites for estimating browse utilization. During 3 consecutive winters we monitored 108–111 transect segments, each 50 m in length, in a systematic distribution across willow communities and assessed the effects of covariates potentially predictive of variation in browsing. Mean annual estimated browse utilization across all segments was 11.5% of sampled twigs in 2008 (95% CI = 9.4 – 13.7%), 8.0% in 2009 (95% CI = 6.2 – 9.8%), and 8.3% in 2010 (95% CI = 6.5 – 10.1%). Modeling of variation in browse utilization revealed positive relationships with the proportion of preferred species (β = 0.44,P = 0.05) and previously browsed willow plants (β = 3.13, P < 0.001), and a negative relationship with willow patch width (β = 0.002, P < 0.001). We found that planeleaf (Salix planifolia), Wolf ʼs (S. wolfii), and Boothʼs willow (S. boothii) were the most consistently preferred species, whereas Drummondʼs (S. drummondiana) and Geyer willow (S. geyeriana) willow were moderately preferred; Lemmonʼs willow (S. lemmonii) was used less than expected. Power analyses indicated that detecting a 10% increase in browse utilization with 95% confidence in consecutive years required measuring 38–41, 50-m segments. Because systems with low and heterogeneous browse utilization of willow present challenges for efficient monitoring, we encourage power analyses as a means of evaluating sampling protocols, in addition to consideration of covariates predictive of spatiotemporal heterogeneity

Rubble Pile Characterization Model

Rubble piles created following the collapse of a building in a combat situation can significantly impact mission accomplishment, particularly in the area of movement and maneuver. Rubble characteristics must be known, for example, in order to predict the ability of a vehicle to override the collateral damage from weapon effects in urban areas. Two types of models are developed: a first-order model and a first-principles-based model. In both models, we assume complete rubblization of the building and develop a rubble profile model using the size and composition of the collapsed structure to predict the rubble volume. In both cases, this profile model includes the size of the footprint area surrounding the original building assuming that the rubble is free to expand horizontally as well as the resulting height of such a rubble pile. Empirical data is now needed to verify the predictive capabilities of these models

Egg Quality Assurance Programs and Egg-associated Salmonella Enteritidis Infections, United States

A 1% increase in eggs produced under egg quality assurance programs was associated with a 0.14% decrease in Salmonella Enteritidis incidence

Phase diagram of a Heisenberg spin-Peierls model with quantum phonons

Using a new version of the density-matrix renormalization group we determine the phase diagram of a model of an antiferromagnetic Heisenberg spin chain where the spins interact with quantum phonons. A quantum phase transition from a gapless spin-fluid state to a gapped dimerized phase occurs at a non-zero value of the spin-phonon coupling. The transition is in the same universality class as that of a frustrated spin chain, which the model maps to in the anti-adiabatic limit. We argue that realistic modeling of known spin-Peierls materials should include the effects of quantum phonons.Comment: RevTeX, 5 pages, 3 eps figures included using epsf. Improved theories in adiabatic and non-adiabatic regimes give better agreement with DMRG. This version accepted in Physical Review Letter

Universal Quake Statistics: From Compressed Nanocrystals to Earthquakes

Slowly-compressed single crystals, bulk metallic glasses (BMGs), rocks, granular materials, and the earth all deform via intermittent slips or “quakes”. We find that although these systems span 12 decades in length scale, they all show the same scaling behavior for their slip size distributions and other statistical properties. Remarkably, the size distributions follow the same power law multiplied with the same exponential cutoff. The cutoff grows with applied force for materials spanning length scales from nanometers to kilometers. The tuneability of the cutoff with stress reflects “tuned critical” behavior, rather than self-organized criticality (SOC), which would imply stress-independence. A simple mean field model for avalanches of slipping weak spots explains the agreement across scales. It predicts the observed slip-size distributions and the observed stress-dependent cutoff function. The results enable extrapolations from one scale to another, and from one force to another, across different materials and structures, from nanocrystals to earthquakes

Charged AdS Black Holes and Catastrophic Holography

We compute the properties of a class of charged black holes in anti-de Sitter space-time, in diverse dimensions. These black holes are solutions of consistent Einstein-Maxwell truncations of gauged supergravities, which are shown to arise from the inclusion of rotation in the transverse space. We uncover rich thermodynamic phase structures for these systems, which display classic critical phenomena, including structures isomorphic to the van der Waals-Maxwell liquid-gas system. In that case, the phases are controlled by the universal `cusp' and `swallowtail' shapes familiar from catastrophe theory. All of the thermodynamics is consistent with field theory interpretations via holography, where the dual field theories can sometimes be found on the world volumes of coincident rotating branes.Comment: 19 pages, revtex, psfig, 6 multicomponent figures, typos, references and a few remarks have been repaired, and adde