SPATIAL ECOLOGY AND HABITAT USE OF THE WESTERN MASSASAUGA (SISTRURUS TERGEMINUS) IN NEBRASKA

We used radiotelemetry during 2004 and 2005 to investigate seasonal movements and habitat use and to improve our understanding of how land management practices were affecting Western Massasauga (Sistrurus tergeminus) populations in Nebraska. We found Western Massasaugas to brumate in crayfish burrows 100% of the time, and spring emergence occurred during March - April. The longest movements occurred during May when snakes were moving away from brumation sites to summer habitat, after which movements decreased until a second peak in August. We did not find significant differences between male and female activity area, range length, total distance moved, daily movement, or distance from spring and fall brumation sites. However the core activity range of females was significantly less than that of males. During the active season, grassland habitat was used 75.6% of the time compared to habitats of grassland-shrubs (10.7%), hydrophilic vegetation (9.1%), woodlands (3.1%), and shrublands (1.5%). Identifying variations in a species spatial ecology is important for achieving long-term conservation goals because life history events, resource availability, and land management practices may have an effect on seasonal movements and habitat use. The results of our study demonstrate the need for, and some of the necessary data for, improved land management planning in order to meet conservation needs of the Western Massasauga in Nebraska

From Random Matrices to Stochastic Operators

We propose that classical random matrix models are properly viewed as finite difference schemes for stochastic differential operators. Three particular stochastic operators commonly arise, each associated with a familiar class of local eigenvalue behavior. The stochastic Airy operator displays soft edge behavior, associated with the Airy kernel. The stochastic Bessel operator displays hard edge behavior, associated with the Bessel kernel. The article concludes with suggestions for a stochastic sine operator, which would display bulk behavior, associated with the sine kernel.Comment: 41 pages, 5 figures. Submitted to Journal of Statistical Physics. Changes in this revision: recomputed Monte Carlo simulations, added reference [19], fit into margins, performed minor editin

Breadboard linear array scan imager using LSI solid-state technology

The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained

Structural Relationship between Negative Thermal Expansion and Quartic Anharmonicity of Cubic ScF_3

Cubic scandium trifluoride (ScF_3) has a large negative thermal expansion over a wide range of temperatures. Inelastic neutron scattering experiments were performed to study the temperature dependence of the lattice dynamics of ScF3 from 7 to 750 K. The measured phonon densities of states show a large anharmonic contribution with a thermal stiffening of modes around 25 meV. Phonon calculations with first-principles methods identified the individual modes in the densities of states, and frozen phonon calculations showed that some of the modes with motions of F atoms transverse to their bond direction behave as quantum quartic oscillators. The quartic potential originates from harmonic interatomic forces in the DO_9 structure of ScF_3, and accounts for phonon stiffening with the temperature and a significant part of the negative thermal expansion

An Anisotropic Ballistic Deposition Model with Links to the Ulam Problem and the Tracy-Widom Distribution

We compute exactly the asymptotic distribution of scaled height in a (1+1)--dimensional anisotropic ballistic deposition model by mapping it to the Ulam problem of finding the longest nondecreasing subsequence in a random sequence of integers. Using the known results for the Ulam problem, we show that the scaled height in our model has the Tracy-Widom distribution appearing in the theory of random matrices near the edges of the spectrum. Our result supports the hypothesis that various growth models in $(1+1)$ dimensions that belong to the Kardar-Parisi-Zhang universality class perhaps all share the same universal Tracy-Widom distribution for the suitably scaled height variables.Comment: 5 pages Revtex, 3 .eps figures included, new references adde

Benefits and challenges of multi-level learner rural general practices – an interview study with learners, staff and patients

Background: General practices vary in the provision of training and education. Some practices have training as a major focus with the presence of multi-level learners and others host single learner groups or none at all. This study investigates the educational benefits and challenges associated with 'multi-level learner' practices. Methods: This paper comprised three case studies of rural general practices with multiple levels of learners. Qualitative data were collected from 29 interviews with learners (n = 12), staff (n = 12) and patients (n = 5). Interviews were initially analyzed using open and axial coding and thematic analysis. Results: Thematic analysis showed 'multi-level learning' in general practices has benefits and challenges to learners and the practice. Learner benefits included knowledge exchange, the opportunity for vertical peer learning, a positive learning environment and the development of a supportive network. The presence of multi-level learners promoted sharing of knowledge with all staff, a sense of community, an increase in patient services and enthused supervisors. Challenges for learners included perception of decreased access to supervisors, anxiety with peer observation, reduced access to patient presentations and patient reluctance to be seen by a learner. Practice challenges were administration requirements, high learner turnover, infrastructure requirements and the requirement for supervisors to cater to a range of learner level needs. Conclusions: The presence of medical students, interns and registrars in general practice has educational benefits to the learners extending to the other stakeholders (staff and patients). Multi-level learners present challenges to the learners and the practice by increasing pressures on resources, staff (administrative and supervisors) and infrastructure

Variance Calculations and the Bessel Kernel

In the Laguerre ensemble of N x N (positive) hermitian matrices, it is of interest both theoretically and for applications to quantum transport problems to compute the variance of a linear statistic, denoted var_N f, as N->infinity. Furthermore, this statistic often contains an additional parameter alpha for which the limit alpha->infinity is most interesting and most difficult to compute numerically. We derive exact expressions for both lim_{N->infinity} var_N f and lim_{alpha->infinity}lim_{N->infinity} var_N f.Comment: 7 pages; resubmitted to make postscript compatibl

Managing Information in a Service Industry to Enhance Buyer/Supplier Relationships

Information technology has allowed motor carriers to enhance the visibility of the service process to provide shippers an incentive for shipper/carrier partnerships. In today’s business environment, information technology offers customers the ability to take an active part in the service process, without actually being present in the service setting. Since the transportation industry represents a service characterized by low customer contact, little information exchange and a lack of influence over the production process; marketing challenges are great and high sales opportunities are minimal. In an attempt to overcome these problems, motor carriers have installed satellite communications systems to increase customer contact and interaction that will lead to greater customer satisfaction and long term relationships. A number of case studies of shippers that currently use carriers employing satellite communications are examined and the potential benefits discussed. An inventory-theoretic model of transportation choice is developed and future research directions are discussed

Universal Distributions for Growth Processes in 1+1 Dimensions and Random Matrices

We develop a scaling theory for KPZ growth in one dimension by a detailed study of the polynuclear growth (PNG) model. In particular, we identify three universal distributions for shape fluctuations and their dependence on the macroscopic shape. These distribution functions are computed using the partition function of Gaussian random matrices in a cosine potential.Comment: 4 pages, 3 figures, 1 table, RevTeX, revised version, accepted for publication in PR