386 research outputs found
Estimating the Value of Medal Success at the 2010 Winter Olympic Games
We estimate Canadiansâ willingness to pay (WTP) for success by Team Canada in the 2010 Winter Olympics. The Canadian government subsidized elite athletes in the run up to the 2010 Games through the Own the Podium program, which was designed to increase Canadaâs medal count. WTP estimates from a contingent valuation method (CVM) study using data from nationally representative surveys before and after the Games suggest that Own the Podium generated intangible benefits of between 3 and 5 times its cost. The aggregate value of the intangible benefits generated by the program was between 3.4 billion. Key Words: Olympic Games, contingent valuation method, willingness to pay
Shorebirds Breed in Unusually High Densities in the Teshekpuk Lake Special Area, Alaska
On the Arctic Coastal Plain of the National Petroleum Reserve-Alaska (NPR-A), the Teshekpuk Lake Special Area (TLSA) was recognized to protect outstanding wildlife values. Although information has accumulated on the TLSAâs value to caribou and waterfowl, its importance to breeding shorebirds remains largely unquantified. Therefore, we undertook a broad-scale ground study to estimate the population size and density of shorebirds breeding in the TLSA. From a series of plot surveys conducted from 2006 to 2008, we estimated a detection-adjusted total breeding population of more than 573 000 shorebirds and an overall density of 126 shorebirds/km2. Most shorebird species had their greatest densities on the Outer Coastal Plain or had approximately equal densities on Outer and Inner Coastal Plains; only two species had their greatest densities on the Inner Coastal Plain. The greatest densities of breeding shorebirds occurred immediately around Teshekpuk Lake. The TLSA supported more than 10% of the biogeographic populations of black-bellied plover (Pluvialis squatarola), semipalmated sandpiper (Calidris pusilla), and dunlin (C. alpina). Breeding shorebird density in the TLSA is one of the highest in the NPR-A, on Alaskaâs North Slope, and throughout the circumpolar Arctic. Our results, coupled with previous information on waterfowl and caribou, indicate that the area around Teshekpuk Lake and the recognized goose molting area northeast of the lake should be protected from oil and gas development.Sur la plaine cĂŽtiĂšre arctique de la rĂ©serve pĂ©troliĂšre nationale-Alaska (NPRA), la rĂ©gion spĂ©ciale du lac Teshekpuk (TLSA) a Ă©tĂ© crĂ©Ă©e dans le but de protĂ©ger les valeurs exceptionnelles de la faune. MĂȘme sâil existe beaucoup dâinformation sur la valeur du caribou et de la sauvagine de la TLSA, lâimportance quâelle revĂȘt en matiĂšre dâoiseaux de rivage nicheurs demeure peu quantifiĂ©e. Nous avons par consĂ©quent entrepris de faire une Ă©tude sur le terrain Ă grande Ă©chelle pour estimer la taille et la densitĂ© de la population dâoiseaux de rivage nichant dans la TLSA. Ă partir dâune sĂ©rie dâenquĂȘtes rĂ©alisĂ©es de 2006 Ă 2008, nous avons estimĂ© que le total redressĂ© en fonction de la dĂ©tection de la population nicheuse sâĂ©tablissait Ă plus de 573 000 oiseaux de rivage, et que la densitĂ© gĂ©nĂ©rale sâĂ©levait Ă 126 oiseaux de rivage/km2. Les plus grandes densitĂ©s de la plupart des espĂšces dâoiseaux de rivage se trouvaient sur la plaine cĂŽtiĂšre extĂ©rieure ou encore, les densitĂ©s Ă©taient environ Ă©gales entre les plaines cĂŽtiĂšres intĂ©rieure et extĂ©rieure. Seulement deux espĂšces avaient leurs plus fortes densitĂ©s sur la plaine cĂŽtiĂšre intĂ©rieure. Les plus grandes densitĂ©s dâoiseaux de rivage se manifestaient immĂ©diatement autour du lac Teshekpuk. La TLSA accueillait plus de 10 % des populations biogĂ©ographiques de pluviers argentĂ©s (Pluvialis squatarola), de bĂ©casseaux semipalmĂ©s (Calidris pusilla) et de bĂ©casseaux variables (C. alpina). La densitĂ© dâoiseaux nicheurs dans la TLSA est lâune des plus Ă©levĂ©es de la NPR-A, sur le versant nord de lâAlaska et Ă lâĂ©chelle de lâArctique circumpolaire. Nos rĂ©sultats, jumelĂ©s Ă lâinformation obtenue antĂ©rieurement au sujet de la sauvagine et du caribou, indiquent que la rĂ©gion autour du lac Teshekpuk et la rĂ©gion reconnue pour la mue des oies au nord-est du lac devraient ĂȘtre protĂ©gĂ©es contre la mise en valeur pĂ©troliĂšre et gaziĂšre
Cdc13 OB2 Dimerization Required for Productive Stn1 Binding and Efficient Telomere Maintenance
SummaryCdc13 is an essential yeast protein required for telomere length regulation and genome stability. It does so via its telomere-capping properties and by regulating telomerase access to the telomeres. The crystal structure of the Saccharomyces cerevisiae Cdc13 domain located between the recruitment and DNA binding domains reveals an oligonucleotide-oligosaccharide binding fold (OB2) with unusually long loops extending from the core of the protein. These loops are involved in extensive interactions between two Cdc13 OB2 folds leading to stable homodimerization. Interestingly, the functionally impaired cdc13-1 mutation inhibits OB2 dimerization. Biochemical assays indicate OB2 is not involved in telomeric DNA or Stn1 binding. However, disruption of the OB2 dimer in full-length Cdc13 affects Cdc13-Stn1 association, leading to telomere length deregulation, increased temperature sensitivity, and Stn1 binding defects. We therefore propose that dimerization of the OB2 domain of Cdc13 is required for proper Cdc13, Stn1, Ten1 (CST) assembly and productive telomere capping
Distribution of Breeding Shorebirds on the Arctic Coastal Plain of Alaska
Available information on the distribution of breeding shorebirds across the Arctic Coastal Plain of Alaska is dated, fragmented, and limited in scope. Herein, we describe the distribution of 19 shorebird species from data gathered at 407 study plots between 1998 and 2004. This information was collected using a single-visit rapid area search technique during territory establishment and early incubation periods, a time when social displays and vocalizations make the birds highly detectable. We describe the presence or absence of each species, as well as overall numbers of species, providing a regional perspective on shorebird distribution. We compare and contrast our shorebird distribution maps to those of prior studies and describe prominent patterns of shorebird distribution. Our examination of how shorebird distribution and numbers of species varied both latitudinally and longitudinally across the Arctic Coastal Plain of Alaska indicated that most shorebird species occur more frequently in the Beaufort Coastal Plain ecoregion (i.e., closer to the coast) than in the Brooks Foothills ecoregion (i.e., farther inland). Furthermore, the occurrence of several species indicated substantial longitudinal directionality. Species richness at surveyed sites was highest in the western portion of the Beaufort Coastal Plain ecoregion. The broad-scale distribution information we present here is valuable for evaluating potential effects of human development and climate change on Arctic-breeding shorebird populations.Les renseignements qui existent en matiĂšre de rĂ©partition des oiseaux de rivage en reproduction sur la plaine cĂŽtiĂšre de lâArctique en Alaska sont anciens, fragmentĂ©s et restreints. Ici, nous dĂ©crivons la rĂ©partition de 19 espĂšces dâoiseaux de rivage Ă partir de donnĂ©es recueillies Ă 407 lieux de recherche entre 1998 et 2004. Cette information a Ă©tĂ© recueillie grĂące Ă une technique de recherche consistant en une seule visite rapide durant les pĂ©riodes dâĂ©tablissement du territoire et de dĂ©but dâincubation, pĂ©riodes pendant lesquelles les comportements sociaux et les vocalisations permettent de bien repĂ©rer les oiseaux. Nous dĂ©crivons la prĂ©sence ou lâabsence de chaque espĂšce, de mĂȘme que le nombre gĂ©nĂ©ral dâespĂšces, ce qui procure une perspective rĂ©gionale de la rĂ©partition des oiseaux de rivage. Nous comparons et contrastons nos cartes de rĂ©partition des oiseaux de rivage Ă celles dâĂ©tudes antĂ©rieures, en plus de dĂ©crire les tendances les plus marquĂ©es en matiĂšre de rĂ©partition des oiseaux de rivage. Notre examen de la variation latitudinale et longitudinale en matiĂšre de rĂ©partition et de nombre dâespĂšces dâoiseaux de rivage Ă lâĂ©chelle de la plaine cĂŽtiĂšre arctique de lâAlaska nous a permis de constater que la plupart des espĂšces dâoiseaux de rivage se manifestaient plus souvent dans la rĂ©gion Ă©cologique de la plaine cĂŽtiĂšre de Beaufort (câest-Ă -dire plus proche de la cĂŽte) que dans la rĂ©gion Ă©cologique des contreforts de Brooks (câest-Ă -dire plus Ă lâintĂ©rieur des terres). Par ailleurs, lâoccurrence de plusieurs espĂšces indiquait une directionalitĂ© longitudinale substantielle. La richesse des espĂšces aux sites Ă lâĂ©tude Ă©tait Ă son meilleur dans la partie ouest de la rĂ©gion Ă©cologique de la plaine cĂŽtiĂšre de Beaufort. Les renseignements sur la rĂ©partition Ă grande Ă©chelle que nous prĂ©sentons ici jouent un rĂŽle dans lâĂ©valuation des effets Ă©ventuels des travaux de mise en valeur par lâĂȘtre humain et du changement climatique sur les populations dâoiseaux de rivage en reproduction de lâArctique
An Open System for Social Computation
Part of the power of social computation comes from using the collective intelligence of humans to tame the aggregate uncertainty of (otherwise) low veracity data obtained from human and automated sources. We have witnessed a surge in development of social computing systems but, ironically, there have been few attempts to generalise across this activity so that creation of the underlying mechanisms themselves can be made more social. We describe a method for achieving this by standardising patterns of social computation via lightweight formal specifications (we call these social artifacts) that can be connected to existing internet architectures via a single model of computation. Upon this framework we build a mechanism for extracting provenance meta-data across social computations
Composite Fermions, Edge Currents and the Fractional Quantum Hall Effect
We present a theory of composite fermion edge states and their transport
properties in the fractional and integer quantum Hall regimes. We show that the
effective electro-chemical potentials of composite fermions at the edges of a
Hall bar differ, in general, from those of electrons. An expression for the
difference is given. Composite fermion edge states of three different types are
identified. Two of the three types have no analog in previous theories of the
integer or fractional quantum Hall effect. The third type includes the usual
integer edge states. The direction of propagation of the edge states agrees
with experiment. The present theory yields the observed quantized Hall
conductances at Landau level filling fractions p/(mp+-1), for m=0,2,4, p=
1,2,3,... It explains the results of experiments that involve conduction across
smooth potential barriers and through adiabatic constrictions, and of
experiments that involve selective population and detection of fractional edge
channels. The relationship between the present work and Hartree theories of
composite fermion edge structure is discussed.Comment: 19 pages + 6 figures. Self-unpacking uuencoded postscript. To appear
in Physical Review B. Revised version has more details in the Appendix and a
discussion of one more experiment in Section
Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae
Telomere capping conceals chromosome ends from exonucleases and checkpoints, but the full range of capping mechanisms is not well defined. Telomeres have the potential to form G-quadruplex (G4) DNA, although evidence for telomere G4 DNA function in vivo is limited. In budding yeast, capping requires the Cdc13 protein and is lost at nonpermissive temperatures in cdc13-1 mutants. Here, we use several independent G4 DNA-stabilizing treatments to suppress cdc13-1 capping defects. These include overexpression of three different G4 DNA binding proteins, loss of the G4 DNA unwinding helicase Sgs1, or treatment with small molecule G4 DNA ligands. In vitro, we show that protein-bound G4 DNA at a 3\u27 overhang inhibits 5\u27-\u3e 3\u27 resection of a paired strand by exonuclease I. These findings demonstrate that, at least in the absence of full natural capping, G4 DNA can play a positive role at telomeres in vivo
Exploring Human/Animal Intersections: Converging Lines of Evidence in Comparative Models of Aging
At a symposium convened on March 8, 2007 by the Institute on Aging at the University of Pennsylvania, researchers from the Universityâs Schools of Medicine and Veterinary Medicine explored the convergence of aging research emerging from the two schools. Studies in human patients, animal models, and companion animals have revealed different but complementary aspects of the aging process, ranging from fundamental biologic aspects of aging to the treatment of age-related diseases, both experimentally and in clinical practice. Participants concluded that neither animal nor human research alone will provide answers to most questions about the aging process. Instead, an optimal translational research model supports a bidirectional flow of information from animal models to clinical research
Status of Muon Collider Research and Development and Future Plans
The status of the research on muon colliders is discussed and plans are
outlined for future theoretical and experimental studies. Besides continued
work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy
collider, many studies are now concentrating on a machine near 0.1 TeV (CoM)
that could be a factory for the s-channel production of Higgs particles. We
discuss the research on the various components in such muon colliders, starting
from the proton accelerator needed to generate pions from a heavy-Z target and
proceeding through the phase rotation and decay ()
channel, muon cooling, acceleration, storage in a collider ring and the
collider detector. We also present theoretical and experimental R & D plans for
the next several years that should lead to a better understanding of the design
and feasibility issues for all of the components. This report is an update of
the progress on the R & D since the Feasibility Study of Muon Colliders
presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A.
Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics
(Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics,
Accelerators and Beam
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