Route Selection to Minimize Helicopter Disturbance of Molting Pacific Black Brant: A Simulation

I used a previously described simulation model to assess the effects of helicopter activity on approximately 18 000 molting Pacific black brant (Branta bernicla nigricans) near Teshekpuk Lake, Alaska. Bell 206 and Bell 412 helicopters were simulated flying across the molting grounds along six flight lines at various altitudes and frequencies between two airfields. The model determined the behavioral and energetic responses of every bird encountered by the aircraft during an overflight, then calculated the weight of these birds at the end of wing molt. Body condition of the brant, reflected in weight loss, was used to quantify the impact of helicopter disturbance. The number of birds in each of five risk categories was determined for each route, altitude, helicopter type, and overflight frequency. Flight lines and overflight patterns that minimized disturbance to the molting population were identified. Slightly altering the direct route between the two airfields resulted in up to 91% fewer birds experiencing heavy weight loss. Flying either helicopter type around the southern edge of the molting grounds caused the least disturbance; flying parallel to the coast, 1.6 km inland, caused the most. The Bell 412 caused up to 15% more weight loss than did the smaller helicopter. Weight loss along a given flight line can be reduced by 1) flying at altitudes greater than 1065 m altitude, 2) flying only when most brant are in their second week of molt, 3) minimizing flight frequency, and 4) avoiding use of the larger Bell 412 when possible.Key words: brant, human disturbance, aircraft, Arctic Coastal Plain, simulation model, feather moltOn s'est servi d'un modèle de simulation décrit précédemment pour évaluer les répercussions de l'activité liée à l'utilisation d'un hélicoptère sur environ 18 000 bernaches noires (Branta bernicla nigricans) en période de mue près de Teshekpuk Lake en Alaska. On a simulé le vol d'hélicoptères Bell 206 et Bell 412 au-dessus des zones de mue le long de six trajectoires de vol à différentes altitudes et fréquences entre deux terrains d'aviation. Le modèle a déterminé les réactions comportementales et énergétiques de chaque oiseau rencontré par l'appareil durant un survol, puis a calculé le poids de ces oiseaux à la fin de la mue des ailes. On a utilisé l'état du corps de la bernache, reflété par la perte de poids, afin de quantifier les effets des perturbations causées par l'hélicoptère. Dans chacune des cinq catégories à risque, on a déterminé le nombre d'oiseaux pour chaque route, altitude, type d'hélicoptère et fréquence de survol. On a identifié les trajectoires de vol et les schémas de survol qui minimisaient les perturbations pour la population en période de mue. Une légère modification au trajet direct entre les deux terrains d'aviation a eu pour résultat que 91 p. cent moins d'oiseaux ont subi une importante perte de poids. Le survol de l'un ou l'autre des types d'hélicoptère dans la périphérie méridionale des aires de mue a produit le moins de perturbation; le survol parallèle à la côte, à 1,6 km à l'intérieur des terres en a causé le plus. Le Bell 412 a provoqué jusqu'à 15 p. cent de plus de perte de poids que l'hélicoptère plus petit. On peut réduire la perte de poids le long d'un trajet de vol donné en 1) volant à plus de 1065 m d'altitude, 2) en ne volant que lorsque la plupart des bernaches sont dans leur deuxième semaine de mue, 3) en minimisant la fréquence des vols et 4) en évitant d'utiliser le plus gros hélicoptère Bell 412 lorsque c'est possible.Mots clés: bernache cravant, perturbation humaine, aéronef, plaine côtière arctique, modèle de simulation, mue des plume

Concepts and analysis for precision segmented reflector and feed support structures

Several issues surrounding the design of a large (20-meter diameter) Precision Segmented Reflector are investigated. The concerns include development of a reflector support truss geometry that will permit deployment into the required doubly-curved shape without significant member strains. For deployable and erectable reflector support trusses, the reduction of structural redundancy was analyzed to achieve reduced weight and complexity for the designs. The stiffness and accuracy of such reduced member trusses, however, were found to be affected to a degree that is unexpected. The Precision Segmented Reflector designs were developed with performance requirements that represent the Reflector application. A novel deployable sunshade concept was developed, and a detailed parametric study of various feed support structural concepts was performed. The results of the detailed study reveal what may be the most desirable feed support structure geometry for Precision Segmented Reflector/Large Deployable Reflector applications

Developing Broad Business Perspective Competencies By Partnering With Practitioners

The CPA Vision Project - 2011 and Beyond) is a blueprint for the accounting profession of the 21st Century. From this visioning process the AICPA Core Competency Framework for Entry into the Accounting Profession (1999) was developed. It is from this framework that accounting educators are invited to adjust curriculum to provide students with the opportunity to develop these functional, personal, and broad business perspective core competencies so that students can meet the accounting profession challenges of the 21st century. This paper provides a specific model for developing broad business perspective competencies by partnering with a practitioner. Although using professionals in the classroom is not a new idea, this paper offers a unique perspective of the process by juxtaposing the perspectives of the academic and the practitioner in the processes of developing the partnership, planning the classroom event (which includes developing the broad business perspective competencies), designing and collecting student feedback, and evaluating the results of the classroom event and partnership

Quantitative bedrock geology of the continents and large-scale drainage regions

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 8 (2007): Q06009, doi:10.1029/2006GC001544.We quantitatively analyze the area-age distribution of sedimentary, extrusive volcanic, and endogenous (plutonic and/or metamorphic) bedrock on the basis of data from the most recent digital Geological Map of the World at a scale of 1:25,000,000. The spatial resolution of the digital bedrock data averages 13,905 km2 per polygon. Comparison of certain regions of the world, previously analyzed at higher spatial resolution, with the low-resolution world data reveals general consistency in the areal exposure of major rock types as well as a minor systematic bias toward older average bedrock ages in the global data set. Application of the global bedrock data to 19 large-scale drainage regions and three large, internally drained regions reveals considerable regional variability of Earth's bedrock geology that is consistent with the dominant geotectonic setting of the respective drainage region.B.P.E. acknowledges financial support from the United States National Science Foundation (NSF-EAR- 0125873) and from the Woods Hole Oceanographic Institution

Quantitative bedrock geology of east and Southeast Asia (Brunei, Cambodia, eastern and southeastern China, East Timor, Indonesia, Japan, Laos, Malaysia, Myanmar, North Korea, Papua New Guinea, Philippines, far-eastern Russia, Singapore, South Korea, Taiwan, Thailand, Vietnam)

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 5 (2004): Q01B06, doi:10.1029/2003GC000619.We quantitatively analyze the area-age distribution of sedimentary, igneous and metamorphic bedrock based on data from the most recent digital geologic maps of East and Southeast Asia (Coordinating Committee for Coastal and Offshore Geosciences Programmes in East and Southeast Asia (CCOP) and the Geologic Survey of Japan, 1997; 1:2,000,000), published as Digital Geoscience Map G-2 by the Geological Survey of Japan. Sedimentary rocks, volcanic rocks, plutonic rocks, ultramafic rocks and metamorphic rocks cover 73.3%, 8.5%, 8.8%, 0.9%, and 8.6% of the surface area, respectively. The average ages of major lithologic units, weighted according to bedrock area, are as follows: sedimentary rocks (average stratigraphic age of 123 Myr/median age of 26 Myr), volcanic rocks (84 Myr/20 Myr), intrusive rocks (278 Myr/195 Myr), ultramafic rocks (unknown) and metamorphic rocks (1465 Myr/1118 Myr). The variability in lithologic composition and age structure of individual countries reflects the complex tectonic makeup of this region that ranges from Precambrian cratons (e.g., northeast China and North Korea) to Mesozoic-Cenozoic active margins (e.g., Japan, the Philippines, Indonesia and New Guinea). The spatial resolution of the data varies from 44 km2 per polygon (Japan) to 1659 km2 per polygon (Taiwan) and is, on average (490 km2/polygon), similar to our previous analyses of the United States of America and Canada. The temporal and spatial resolution is sufficiently high to perform age-area analyses of individual river basins larger than ∼10,000 km2 and to quantitatively evaluate the relationship between bedrock geology and river chemistry. As many rivers draining tropical, mountainous islands of East and Southeast Asia have a disproportionate effect on the dissolved and particulate load delivered to the world oceans, bedrock geology in such river drainage basins disproportionately affect ocean chemistry.Financial support was provided through the U.S. National Science Foundation (NSF-EAR-0125873) to BPE

Regge Calculus as a Fourth Order Method in Numerical Relativity

The convergence properties of numerical Regge calculus as an approximation to continuum vacuum General Relativity is studied, both analytically and numerically. The Regge equations are evaluated on continuum spacetimes by assigning squared geodesic distances in the continuum manifold to the squared edge lengths in the simplicial manifold. It is found analytically that, individually, the Regge equations converge to zero as the second power of the lattice spacing, but that an average over local Regge equations converges to zero as (at the very least) the third power of the lattice spacing. Numerical studies using analytic solutions to the Einstein equations show that these averages actually converge to zero as the fourth power of the lattice spacing.Comment: 14 pages, LaTeX, 8 figures mailed in separate file or email author directl

Density, Spatial Distribution and Size Structure of Sea Urchins in Florida Keys Coral Reef and Hard-Bottom Habitats

The 1983-84 Caribbean-wide mortality of the long-spined sea urchin Diadema antillarum Philippi was followed by a 2nd mortality event during 1991 in the Florida Keys. Pre-mortality sea urchin densities were up to 5 ind. m-2 and the large scale decline of D. antillarum is considered to be 1 factor affecting community dynamics of Florida Keys reefs. During 1999-2000, we surveyed 125 sites using a stratified random sampling design in shallow-water coral reef and hard-bottom habitats. Strip transects were sampled to assess density, habitat utilization and size structure patterns among habitat types, regional sectors and between fished and protected areas. Nearly 17 yr after the mass mortality, D. antillarum has not recovered to pre-1983 levels, with current densities no greater than 0.05 ind. m-2, and small test sizes (1 to 2 cm) dominate. Other sea urchins such as Eucidaris tribuloides (Lamarck) and Echinometra viridis Agassiz show density and habitat distribution patterns similar to historical observations

Multiple Spatial Scale Assessment of Coral Reef and Hard-Bottom Community Structure in the Florida Keys National Marine Sanctuary

The zoning plan for the Florida Keys National Marine Sanctuary (FKNMS) established 23 relatively small no-fishing zones distributed mostly along the offshore reef tract in 1997. In 1999, a two-stage, stratified random sampling design based on the proportion of coral reef and hard-bottom types within the FKNMS was conducted. Our study focused on differences in coverage, density, and condition of benthic organisms with respect to habitat type, regional variations, and differences between no-fishing zones and reference sites at 80 locations spanning 200 km. Most variables exhibited significant spatial differences by habitat type or between individual no-fishing zones and reference sites (e.g. species richness, coral density, gorgonian density, and recruitment), although some regional differences were also apparent. Many of the differences among the no-fishing zones and reference sites reflect the placement of the zones in well-developed offshore reefs, and for many of the variables targeted, individual zones are as different from one another as from reference sites. These results emphasize the need to address spatial variations at multiple scales, and to consider a range of variables beyond common metrics such as coral cover

Reversible self-assembly of patchy particles into monodisperse icosahedral clusters

We systematically study the design of simple patchy sphere models that reversibly self-assemble into monodisperse icosahedral clusters. We find that the optimal patch width is a compromise between structural specificity (the patches must be narrow enough to energetically select the desired clusters) and kinetic accessibility (they must be sufficiently wide to avoid kinetic traps). Similarly, for good yields the temperature must be low enough for the clusters to be thermodynamically stable, but the clusters must also have enough thermal energy to allow incorrectly formed bonds to be broken. Ordered clusters can form through a number of different dynamic pathways, including direct nucleation and indirect pathways involving large disordered intermediates. The latter pathway is related to a reentrant liquid-to-gas transition that occurs for intermediate patch widths upon lowering the temperature. We also find that the assembly process is robust to inaccurate patch placement up to a certain threshold, and that it is possible to replace the five discrete patches with a single ring patch with no significant loss in yield.Comment: 12 pages, 12 figure