CALL BROADCASTING AND AUTOMATED RECORDERS AS TOOLS FOR ANURAN SURVEYS IN A SUBARCTIC TUNDRA LANDSCAPE

Relatively little is known about population ecology of anurans in arctic and subarctic tundra regions, in part because it is difficult to survey anurans in these landscapes. Anuran survey protocols developed for temperate regions have limited applicability in arctic and subarctic tundra landscapes, which may lack roads and vehicle access, and experience variable and inclement weather during short anuran breeding seasons. To evaluate approaches to address some of the limitations of surveying anurans in tundra landscapes, we assessed the effectiveness of using breeding call broadcasts to increase detection of Boreal Chorus Frogs (Pseudacris maculata) and Wood Frogs (Lithobates sylvaticus) near Cape Churchill, Manitoba, Canada. We also evaluated how counts of anurans derived from automated audio recorders compared with those obtained simultaneously by observers. We detected on average 0.4 additional Wood Frogs per survey when we broadcasted calls (x = 0.82, SD = 1.38), an increase of > 40% compared to surveys without broadcasts (x = 1.24, SD = 1.51; Wilcoxon test; Z = 2.73, P = 0.006). In contrast, broadcasting Boreal Chorus Frog calls did not increase the number of chorus frog detections (Wilcoxon test; Z < 0.001, P > 0.90). Detections of Wood Frogs in a 100-m radius were lower via automated recorders (x = 0.60, SD = 0.87 SD) than by observers during simultaneous surveys (x = 0.96, SD = 1.27 Z = 2.07, P = 0.038), but those of Boreal Chorus Frogs were not different (x = 1.72, SD = 1.31;x = 1.44, SD = 1.5; Z = 1.55, P > 0.121). Our results suggest that broadcasting calls can increase detection of Wood Frogs, and that automated recorders are useful in detecting both Wood Frogs and Boreal Chorus Fogs in arctic and subarctic tundra landscapes

Microhabitat Characteristics of Lapland Longspur, Calcarius lapponicus, Nests at Cape Churchill, Manitoba

We examined microsite characteristics at 21 Lapland Longspur (Calcarius lapponicus) nests and land cover types in which they occurred in Wapusk National Park, Cape Churchill, Manitoba. Nests were located in four of six physiographic-vegetation land-cover types. Regardless of land-cover type, all but one nest was built on a pressure ridge or mound. Nests were built midway between the bottom and top of ridges or mounds with steeper slopes than was randomly available. Longspur nests had a distinctive southwest orientation (P < 0.001). Longspurs selected nest sites that consisted of comparatively greater amounts of shrub species and lesser amounts of moss than were randomly available. Nests were generally well concealed by vegetation (mean = 67.0%) and concealment was negatively associated with amount of graminoid species at the nest (P = 0.0005). Our nesting habitat data may facilitate a better understanding of breeding Lapland Longspur habitat requirements, and potential impacts of habitat degradation by increasing Snow Goose (Chen caerulescens) populations in the study area

Nest-defense Behavior of Mississippi Kites in Urban and Exurban Areas

Mississippi kites (Ictinia mississippiensis) have become an abundant raptor in many urban and exurban areas throughout the Southern Great Plains of the United States. Unfortunately, human–wildlife conflicts have resulted from this juxtaposition of suitable breeding areas for kites and areas that humans frequent, with some kites responding aggressively to humans near nests. To date, there are no data describing the prevalence of aggressive nest defense in the species, making informed management of human and kite conflicts difficult. We assessed and compared the prevalence of aggressive nest-defense by Mississippi kites in an urban area and an exurban area by simulating nest disturbance with a trial pedestrian. Additionally, we examine the relationships between physical features of the nest tree where aggressive behaviors were and were not recorded. Individual kites breeding in the exurban area responded to the trial pedestrian by taking flight from the nesting area, circling overhead, swooping at the pedestrian, or remaining on the nest. In the urban area, kites displayed a more limited suit of responses and either remained on the nest or swooped at the pedestrian. Additionally, kites breeding in the exurban area appeared to respond to experimental disturbance at a greater distance than did urban breeding kites, but not with more attacks on pedestrians. Physical characteristics of the nest tree did not explain aggressive behaviors, thereby suggesting that aggression in Mississippi kites is caused by factors other than nesting location features

Microhabitat Characteristics of Lapland Longspur, Calcarius lapponicus, Nests at Cape Churchill, Manitoba

We examined microsite characteristics at 21 Lapland Longspur (Calcarius lapponicus) nests and land cover types in which they occurred in Wapusk National Park, Cape Churchill, Manitoba. Nests were located in four of six physiographic-vegetation land-cover types. Regardless of land-cover type, all but one nest was built on a pressure ridge or mound. Nests were built midway between the bottom and top of ridges or mounds with steeper slopes than was randomly available. Longspur nests had a distinctive southwest orientation (P < 0.001). Longspurs selected nest sites that consisted of comparatively greater amounts of shrub species and lesser amounts of moss than were randomly available. Nests were generally well concealed by vegetation (mean = 67.0%) and concealment was negatively associated with amount of graminoid species at the nest (P = 0.0005). Our nesting habitat data may facilitate a better understanding of breeding Lapland Longspur habitat requirements, and potential impacts of habitat degradation by increasing Snow Goose (Chen caerulescens) populations in the study area

Minimal Bending Energies of Bilayer Polyhedra

Motivated by recent experiments on bilayer polyhedra composed of amphiphilic molecules, we study the elastic bending energies of bilayer vesicles forming polyhedral shapes. Allowing for segregation of excess amphiphiles along the ridges of polyhedra, we find that bilayer polyhedra can indeed have lower bending energies than spherical bilayer vesicles. However, our analysis also implies that, contrary to what has been suggested on the basis of experiments, the snub dodecahedron, rather than the icosahedron, generally represents the energetically favorable shape of bilayer polyhedra

Path integrals for stiff polymers applied to membrane physics

Path integrals similar to those describing stiff polymers arise in the Helfrich model for membranes. We show how these types of path integrals can be evaluated and apply our results to study the thermodynamics of a minority stripe phase in a bulk membrane. The fluctuation induced contribution to the line tension between the stripe and the bulk phase is computed, as well as the effective interaction between the two phases in the tensionless case where the two phases have differing bending rigidities.Comment: 11 pages RevTex, 4 figure

Some observations on the renormalization of membrane rigidity by long-range interactions

We consider the renormalization of the bending and Gaussian rigidity of model membranes induced by long-range interactions between the components making up the membrane. In particular we analyze the effect of a finite membrane thickness on the renormalization of the bending and Gaussian rigidity by long-range interactions. Particular attention is paid to the case where the interactions are of a van der Waals type.Comment: 11 pages RexTex, no figure

The thermal Casimir effect in lipid bilayer tubules

We calculate the thermal Casimir effect for a dielectric tube of radius $R$ and thickness delta formed from a membrane in water. The method uses a field-theoretic approach in the grand canonical ensemble. The leading contribution to the Casimir free energy behaves as -k_BTL kappa_C/R giving rise to an attractive force which tends to contract the tube. We find that kappa_C ~ 0.3 for the case of typical lipid membrane t-tubules. We conclude that except in the case of a very soft membrane this force is insufficient to stabilize such tubes against the bending stress which tends to increase the radius.Comment: 4 pages no figures RevTe

Triptycene Structure-Directing Agents in Aluminophosphate Synthesis

The synthesis of aluminophosphates is investigated using a number of triptycene-based organic structure-directing agents (OSDA). These OSDAs are designed to synthesize extra-large pore and/or large cavity-containing molecular sieves. Starting from the hydrophobic triptycene molecule, OSDAs are prepared by introducing three amine-based centers that can be charged either by protonation in the acidic aluminophosphate reaction media or through quaternization. VPI-5 is synthesized using these tripytycene OSDAs, and the OSDAs are occluded inside the pores. This synthesis marks the first time VPI-5 has been made as a single phase with an OSDA occluded inside the framework of the as-made material that is not removed by simple washing with water or other solvents. Additionally, several other aluminophosphates with unknown structures are synthesized using these new OSDAs

INCORPORATION OF QUANTUM STATISTICAL FEATURES IN MOLECULAR DYNAMICS

We formulate a method for incorporating quantum fluctuations into molecular- dynamics simulations of many-body systems, such as those employed for energetic nuclear collision processes. Based on Fermi's Golden Rule, we allow spontaneous transitions to occur between the wave packets which are not energy eigenstates. The ensuing diffusive evolution in the space of the wave packet parameters exhibits appealing physical properties, including relaxation towards quantum- statistical equilibrium.Comment: 8 latex pages + 1 uuencoded ps figur