Food Habits of Wolves in Kluane National Park

The food habits of wolves (Canis lupus) were studied at two different den-sites in Kluane National Park in the southwest of the Yukon Territory, in 1972 and 1973, as part of an assessment of predator-prey dynamics in that newly-designated reserve. No published data exist on the diets of wolves in northern British Columbia or the Yukon Territory; the closest available information concerns the wolf populations of Alaska

Landscape Influence on Canis Morphological and Ecological Variation in a Coyote-Wolf C. lupus × latrans Hybrid Zone, Southeastern Ontario

The ecology of Coyote-Wolf (Canis latrans × C. lupus) hybrids has never fully been typified. We studied morphological and ecological variation in Canis within a region of Coyote-Wolf hybridization in southeastern Ontario. We assessed Canis morphology from standard body measurements and ten skull measurements of adult specimens and found that Canis in this region are morphologically intermediate between Algonquin Provincial Park Wolves (C. lupus lycaon) and Coyotes, indicating a latrans × lycaon hybrid origin; however, there is a closer morphological affinity to latrans than lycaon. Analysis of 846 scats indicated dietary habits also intermediate between lycaon and Coyotes. We used a geographic information system (GIS) to assess spatial landscape features (road density, land cover and fragmentation) for six study sites representing three landscape types. We found noticeable variation in Canis morphology and diet in different landscape types. In general, canids from landscape type A (lowest road density, more total forest cover, less fragmentation) displayed more Wolf-like body morphology and consumed a greater proportion of larger prey (Beaver [Castor canadensis] and White-tailed Deer [Odocoileus virginianus]). In comparison, canids from landscape types B and C (higher road density and/or less total forest cover, more fragmentation) were generally more Coyote-like in body and skull morphology and made greater use of medium to small-sized prey (Groundhog [Marmota monax], Muskrat [Ondatra zibethicus] and lagomorphs). These landscape trends in Canis types suggest selection against Wolf-like traits in fragmented forests with high road density. The range of lycaon southeast of Algonquin Provincial Park appears to be limited primarily due to human access and consequent exploitation. We suggest that road density is the best landscape indicator of Canis types in this region of sympatric, hybridizing and unprotected Canis populations

Physical Nucleon Properties from Lattice QCD

We demonstrate that the extremely accurate lattice QCD data for the mass of the nucleon recently obtained by CP-PACS, combined with modern chiral extrapolation techniques, leads to a value for the mass of the physical nucleon which has a systematic error of less than one percent.Comment: 4 pages, 2 figure

The distribution and movement patterns of four woodland caribou herds in Quebec and Labrador

Recent studies of woodland caribou (Rangifer tarandus caribou) in northern Quebec and central Labrador have demonstrated similar patterns of seasonal movements and distribution among four herds. Aerial surveys and radio-telemetry indicated that animals occupied forest-wetland habitat at densities of 0.03 caribou km2, or lower, for most of the year. Although females were widely dispersed at calving individuals demonstrated fidelity toward specific calving locations, in successive years. Caribou did not form large post-calving aggregations. Movement was greatest in the spring, prior to calving, and in the fall, during or immediately after rutting. Caribou were generally sedentary during summer and winter, although some moved relatively long distances to late-winter range. Although the herds occupy continuous range across Quebec and Labrador, our data indicate that the herds are largely discreete and should be managed individually

Nucleon mass and pion loops: Renormalization

Using Dyson--Schwinger equations, the nucleon propagator is analyzed nonperturbatively in a field--theoretical model for the pion--nucleon interaction. Infinities are circumvented by using pion--nucleon form factors which define the physical scale. It is shown that the correct, finite, on--shell nucleon renormalization is important for the value of the mass--shift and the propagator. For physically acceptable forms of the pion--nucleon form factor the rainbow approximation together with renormalization is inconsistent. Going beyond the rainbow approximation, the full pion--nucleon vertex is modelled by its bare part plus a one--loop correction including an effective $\Delta$. It is found that a consistent value for the nucleon mass--shift can be obtained as a consequence of a subtle interplay between wave function and vertex renormalization. Furthermore, the bare and renormalized pion--nucleon coupling constant are approximately equal, consistent with results from the Cloudy Bag Model.Comment: 14 pages, 6 figure

Strange nucleon form factors in the perturbative chiral quark model

We apply the perturbative chiral quark model at one loop to calculate the strange form factors of the nucleon. A detailed numerical analysis of the strange magnetic moments and radii of the nucleon, and also the momentum dependence of the form factors is presented.Comment: 18 pages, 6 figure

Quark-meson coupling model for finite nuclei

A Quark-Meson Coupling (QMC) model is extended to finite nuclei in the relativistic mean-field or Hartree approximation. The ultra-relativistic quarks are assumed to be bound in non-overlapping nucleon bags, and the interaction between nucleons arises from a coupling of vector and scalar meson fields to the quarks. We develop a perturbative scheme for treating the spatial nonuniformity of the meson fields over the volume of the nucleon as well as the nucleus. Results of calculations for spherical nuclei are given, based on a fit to the equilibrium properties of nuclear matter. Several possible extensions of the model are also considered.Comment: 33 pages REVTeX plus 2 postscript figure

Axial Vector Coupling Constant in Chiral Colour Dielectric Model

The axial vector coupling constants of the $\beta$ decay processes of neutron and hyperon are calculated in SU(3) chiral colour dielectric model (CCDM). Using these axial coupling constants of neutron and hyperon, in CCDM we calculate the integrals of the spin dependent structure functions for proton and neutron. Our result is similar to the results obtained by MIT bag and Cloudy bag models.Comment: 9 pages, Latex file, no figure, to appear in Phys. Rev.

Drop Traffic in Microfluidic Ladder Networks with Fore-Aft Structural Asymmetry

We investigate the dynamics of pairs of drops in microfluidic ladder networks with slanted bypasses, which break the fore-aft structural symmetry. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative drop spacing, enabling them to contract, synchronize, expand, or even flip at the ladder exit. Our experiments confirm all these behaviors predicted by theory. Numerical analysis further shows that while ladder networks containing several identical bypasses are limited to nearly linear transformation of input delay between drops, mixed combination of bypasses can cause significant non-linear transformation enabling coding and decoding of input delays.Comment: 4 pages, 5 figure