Measuring the Spin of GRS 1915+105 with Relativistic Disk Reflection

GRS 1915+105 harbors one of the most massive known stellar black holes in the Galaxy. In May 2007, we observed GRS 1915+105 for 117 ksec in the low/hard state using Suzaku. We collected and analyzed the data with the HXD/PIN and XIS cameras spanning the energy range from 2.3-55 keV. Fits to the spectra with simple models reveal strong disk reflection through an Fe K emission line and a Compton back-scattering hump. We report constraints on the spin parameter of the black hole in GRS 1915+105 using relativistic disk reflection models. The model for the soft X-ray spectrum (i.e. < 10 keV) suggests a/M = 0.56(2) and excludes zero spin at the 4 sigma level of confidence. The model for the full broadband spectrum suggests that the spin may be higher, a/M = 0.98(1) (1 sigma confidence), and again excludes zero spin at the 2 sigma level of confidence. We discuss these results in the context of other spin constraints and inner disk studies in GRS 1915+105.Comment: Accepted for publication in Ap

Introduction to the themed issue - Corporate power : agency, communication, influence and social policy

This paper introduces this themed issue of Critical Social Policy on the question of corporate power. Corporate power is recognized as an important agent in social policy making and delivery. However, to date there has been comparatively little attention to the crucial role that lobbying and corporate 'spin' play in helping to shape policy making contexts. This special issue of Critical Social Policy is concerned to bring such issues to the mainstream of social policy analysis. It is argued here that the rise of spin and public relations is a key feature of neoliberalism in the past two decades. These have worked to reshape policy making, resulting in pronounced changes in the content and process of policy making and it is argued that these have tended to marginalize or undermine democratic processes

Long-Term Control of Peary Caribou Numbers by Unpredictable, Exceptionally Severe Snow or Ice Conditions in a Non-equilibrium Grazing System

The number of Peary caribou (Rangifer tarandus pearyi) on the Queen Elizabeth Islands, Canadian High Arctic, is at an all-time known low. Yet some populations are still hunted, and there is no adequate monitoring program in place to determine the consequences. We evaluate information from the Peary caribou population on the south-central Queen Elizabeth Islands as a standard for an accurate and realistic assessment of what controls Peary caribou population dynamics. Between 1973 and 1997, major population crashes related to severe winter or spring weather are known to have occurred on the south-central Queen Elizabeth Islands in four caribou-years (i.e., 1 July–30 June). Population losses were 67% in 1973–74, 33% in 1994–95, 78% in 1995–96, and 83% in 1996–97. There is no evidence for direct density-dependent responses during either the favorable weather years of population growth or during any one of the years with a disastrous die-off. It appears that Peary caribou on the Queen Elizabeth Islands are living in a non-equilibrium grazing system driven mainly by abiotic factors (emergent properties), particularly by exceptionally unfavorable snow or ice conditions. Changing levels of predation by the High Arctic gray wolf (Canis lupus arctos) compound the uncertainty. In this High Arctic ecosystem, non-equilibrium–governed population dynamics plus wolf predation represents an appropriate conceptual model for Peary caribou populations on the Canadian High Arctic islands. The application of our findings to decision making, together with an adequate monitoring program by the responsible agencies, would promote the biological management and ecological conservation of Peary caribou on the Queen Elizabeth Islands.Le nombre de caribous de Peary (Rangifer tarandus pearyi) répertoriés dans les îles de la Reine-Élisabeth, Extrême-Arctique canadien, se trouve au niveau le plus bas à n’avoir jamais été enregistré. Pourtant, certaines populations font toujours l’objet de la chasse et il n’existe aucun programme de surveillance adéquat pour en déterminer les conséquences. Nous évaluons ici des données relatives à la population de caribous de Peary des îles centre-sud de la Reine-Élisabeth afin d’aboutir à une norme d’évaluation précise et réaliste pour déterminer ce qui influence la dynamique de population des caribous de Peary. Entre 1973 et 1997, d’importants déclins de population attribuables aux hivers ou aux printemps rigoureux ont été enregistrés dans le centre-sud des îles de la Reine-Élisabeth sur une période de quatre années-caribous (c’est-à-dire du 1er juillet au 30 juin). Les déclins de population se sont élevés à 67 % en 1973–1974, 33 % en 1994–1995, 78 % en 1995–1996 et 83 % en 1996–1997. Il n’existe aucune preuve de résultats directs dépendant de la densité pendant les années de croissance de la population au cours desquelles les conditions météorologiques étaient favorables ou pendant l’une ou l’autre des années de désastreux déclins. Il semble que le caribou de Peary des îles de la Reine-Élisabeth vive dans un système de pâturage hors équilibre répondant principalement à des facteurs abiotiques (propriétés émergentes), surtout lorsque les conditions d’enneigement ou de glaciation sont exceptionnellement défavorables. L’incertitude est aggravée par les taux de prédation changeants chez le loup arctique (Canis lupus arctos). Dans cet écosystème de l’Extrême-Arctique, les dynamiques de population hors équilibre, alliées à la prédation par le loup, représentent un modèle conceptuel adéquat pour les populations de caribous de Peary des îles de l’Extrême-Arctique canadien. La gestion biologique et la conservation écologique du caribou de Peary dans les îles de la Reine-Élisabeth auraient avantage à tenir compte des constatations émanant de notre étude dans la prise de décisions de même que d’un programme de surveillance convenable de la part des organismes responsables

Single-island home range use by four female Peary caribou, Bathurst Island, Canadian High Arctic, 1993-94

Spatial and temporal use of seasonal, and collectively, annual ranges by four female Peary caribou (Rangifer taran-dus pearyi) was investigated using satellite telemetry. Knowledge of how caribou use space allows a better understanding of their demands on those ranges and enhances evaluation of associated environmental stressors. The study took place during an environmentally favorable caribou-year with high reproduction and calf survival and low (none detected) 1+ yr-old mortality, 1 August 1993 to 31 July 1994, Bathurst Island, south-central Queen Elizabeth Islands, Canadian High Arctic. All four females exhibited a pattern of single-island seasonal, and collectively, annual range use. Estimates of the maximum area encompassed by each individual during the course of the annual-cycle varied from 1735 to 2844 km2 (mean&plusmn;SE = 2284&plusmn;250 km2). Although, there was 46% spatial overlap among individual ranges, temporal isolation resulted in the four individuals maintaining seasonal ranges distinctly separate from each other. This collective area encompassed 4970 km2 and equaled about 31% and 18% of Bathurst Island and the Bathurst Island complex, respectively. Individual wintering areas formed a relatively small portion of each individual's annual range (mean&plusmn;SE=71&plusmn;17 km2): 24 km2, 158 days of occupation, &lt;1% of the annual area; 70 km2, 187 days, 4%; 95 km2, 200 days, 4%; and 94 km2, 172 days, 6%. Seasonal movements were greatest during pre-rut and pre-calving

Binary Encounters With Supermassive Black Holes: Zero-Eccentricity LISA Events

Current simulations of the rate at which stellar-mass compact objects merge with supermassive black holes (called extreme mass ratio inspirals, or EMRIs) focus on two-body capture by emission of gravitational radiation. The gravitational wave signal of such events will likely involve a significant eccentricity in the sensitivity range of the Laser Interferometer Space Antenna (LISA). We show that tidal separation of stellar-mass compact object binaries by supermassive black holes will instead produce events whose eccentricity is nearly zero in the LISA band. Compared to two-body capture events, tidal separations have a high cross section and result in orbits that have a large pericenter and small apocenter. Therefore, the rate of interactions per binary is high and the resulting systems are very unlikely to be perturbed by other stars into nearly radial plunges. Depending on the fraction of compact objects that are in binaries within a few parsecs of the center, the rate of low-eccentricity LISA events could be comparable to or larger than the rate of high-eccentricity events.Comment: Final accepted version: ApJ Letters 2005, 631, L11

Nonrandom Distribution of Antlers Cast by Peary Caribou Bulls, Melville Island, Northwest Territories

An aerial survey was carried out in July 1987 to determine the pattern of distribution of antlers cast by Peary caribou (Rangifer tarandus pearyi) bulls on north-central and northeastern Melville Island, Northwest Territories, Canada. Four transect lines were flown parallel to the coastal shorelines of Hecla and Griper Bay and adjacent Sabine Bay at distances of about 0.8, 2.4, 5.0, and 10.0 km inland. A four-person survey crew was used in a Bell-206B turbo-helicopter flown at about 90 m above ground level and at an air speed of about 160 km/h. We recorded 531 antlers cast by bulls along ca. 1110 km of transects: 55% within 1.6 km of the seacoast and 89% within 3.2 km. Antlers were not randomly distributed along or among transects (p&lt;0.05). The antlers were clumped in distribution and their numbers declined significantly with distance from the seacoast (p&lt;0.05). We suggest that use of such coastal rutting areas by low-density populations of Peary caribou would confer, without any precognition or anticipation on the part of the animals, maximal timely contact between rutting bulls and cows in heat during the short temporal peak of the autumn rut by reducing a two-dimensional search problem to an essentially linear one.Key words: Peary caribou, Rangifer tarandus pearyi, bulls, cast antlers, Melville Island, Northwest Territories&nbsp;R&Eacute;SUM&Eacute;. Un relev&eacute; a&eacute;rien a &eacute;t&eacute; effectu&eacute; en juillet 1987 pour d&eacute;terminer le sch&eacute;ma de distribution des bois perdus par les caribous de Peary (Rangifer tarandus pearyi) m&acirc;les dans le centre-nord et le nord-est de l&rsquo;&icirc;le Melville, dans les Territoires du Nord-Ouest au Canada. Quatre transectsont &eacute;t&eacute; survol&eacute;s, parall&egrave;lement au rivage le long de Hecla et de Griper Bay et de la baie adjacente, Sabine Bay, &agrave; des distances d&rsquo;environ 0,8, 2,4,5,0 et 10,0 km &agrave; l&rsquo;int&eacute;rieur des terres. Une &eacute;quipe compos&eacute;e de quatre individus a effectulee relev&eacute; partir d&rsquo;un h&eacute;licoptere &agrave; turbor&eacute;acteur Bell-206B,volant &agrave; environ 90 m du sol et &agrave; une vitesse a&eacute;rodynamique de 160 km.h . On a relev&eacute; 531 bois perdus par les m&acirc;les le long d&rsquo;environ 1100 km de transects: 55 p. cent &agrave; moins de 1,6 km de la c&ocirc;te, et 89 p. cent &agrave; moins de 3.2 km. Les bois n&rsquo;&eacute;taient pas r&eacute;partis au hasard le long des transects ou parmi eux (p &lt; 0,05). Ils formaient des groupes et leur nombre diminuait de fa&ccedil;on significative lorsqu&rsquo;on s&rsquo;&eacute;loignait la de c&ocirc;te (p &lt; 0,05). On sugg&egrave;re que l&rsquo;utilisation de ces aires de rut c&ocirc;ti&egrave;res par des populations clairsem&eacute;es de caribous de Peary favoriserait - sans qu&rsquo;il y ait pr&eacute;connaissance ou intention de la part de l&rsquo;animal - un contact opportun maximal entre les m&acirc;les et les femelles en rut durant le pic de courte dur&eacute;e du rut automnal, en ramenant le probl&egrave;me de la recherche en deux dimension&agrave;s un probl&egrave;me de recherche essentiellement lin&eacute;aire.Mots cl&eacute;s: caribou de Peary, Rangifer tarandus pearyi, m&acirc;les, bois perdus, &icirc;le Melville, Territoires du Nord-Oues

The Economic Impact of a Junior Club Sporting Event: Caravan Fans

This study investigated the economic impact of visitor’s expenditures at a junior girl’s club sporting event in the city of Denver, Colorado. This study uses a random sample of 2,000 sport fans of which 1,163 surveys were found to be usable (n=1,163). The findings reveal that hosting a club sports national tournament can generate substantial economic benefits and, in some cases, greater than those associated with mega sporting events. Key findings are that economic impact can play a critical role in assessing the potential benefits of hosting small events and that youth sport event managers must make sure to meet the needs of caravan fans. Caravan fans are the parents and family members that attend these events to watch their children participate