Generic Isolated Horizons and their Applications

Boundary conditions defining a generic isolated horizon are introduced. They generalize the notion available in the existing literature by allowing the horizon to have distortion and angular momentum. Space-times containing a black hole, itself in equilibrium but possibly surrounded by radiation, satisfy these conditions. In spite of this generality, the conditions have rich consequences. They lead to a framework, somewhat analogous to null infinity, for extracting physical information, but now in the \textit{strong} field regions. The framework also generalizes the zeroth and first laws of black hole mechanics to more realistic situations and sheds new light on the `origin' of the first law. Finally, it provides a point of departure for black hole entropy calculations in non-perturbative quantum gravity.Comment: 4 pages, RevTeX. Minor typos were corrected and the fact that, in contrast to Ref [4], isolated horizons are now allowed to have distortion and rotation was clarifie

Lake Ontario Coastal Initiative Action Agenda

The mission of the Lake Ontario Coastal Initiative (LOCI), encompassing all New York State North Coast stakeholders from the Niagara River to the St. Lawrence River, is to enlist and retain broad public commitment for remediation, restoration, protection, conservation and sustainable use of the coastal region. This mission will be accomplished by securing funds and resources to achieve scientific understanding, educate citizens, and implement locally supported priorities, programs and projects as identified through this Initiative

Population change of invasive Dreissena polymorpha in Douglas Lake from 2003 to 2009.

General EcologyField observations led us to believe that populations of Dreissena polymorpha in Douglas Lake were decreasing. We hypothesized that this change was caused by environmental changes such as a change in water level, population dynamics including an approach to carrying capacity, or the reduction of resources such as suitable substrate and phytoplankton supply. Our study followed many of the methods of the Galligan (2005) survey for the best comparison between years. Sampling gave a greatly reduced number from the past survey; we found a total of 358 D. polymorpha in which 213 were living. While in 2005, Galligan found a total of 3437 D. polymorpha. Biomass was calculated from this sampling and was compared with phytoplankton densities; however there were no significant results. The survey for D. polymorpha veligers was also inconclusive as it produced only one veliger. The decrease in population may be a result of biotic environmental changes or an approach to carrying capacity but further specific research would have to be done to pinpoint a specific mechanism for this decrease. Our research provides valuable knowledge of an invasive species that could contribute to the eventual control of Dreissena polymorpha by natural means.http://deepblue.lib.umich.edu/bitstream/2027.42/64582/1/Duffy_Kittikul_Lewandowski_Sliger_2009.pd

Chandra Smells a RRAT: X-ray Detection of a Rotating Radio Transient

"Rotating RAdio Transients" (RRATs) are a newly discovered astronomical phenomenon, characterised by occasional brief radio bursts, with average intervals between bursts ranging from minutes to hours. The burst spacings allow identification of periodicities, which fall in the range 0.4 to 7 seconds. The RRATs thus seem to be rotating neutron stars, albeit with properties very different from the rest of the population. We here present the serendipitous detection with the Chandra X-ray Observatory of a bright point-like X-ray source coincident with one of the RRATs. We discuss the temporal and spectral properties of this X-ray emission, consider counterparts in other wavebands, and interpret these results in the context of possible explanations for the RRAT population.Comment: 5 pages, 2 b/w figures, 1 color figure. To appear in the proceedings of "Isolated Neutron Stars", Astrophysics & Space Science, in pres

Prophylactic Embolization of the Cystic Artery Before Radioembolization: Feasibility, Safety, and Outcomes

PurposeTo evaluate the safety and efficacy of two different methods of proximal cystic artery embolization in patients undergoing yttrium-90 radioembolization.Materials and methodsForty-six patients had cystic artery embolization performed immediately before yttrium-90 radioembolization, either by using Gelfoam pledgets (n = 35) or coils (n = 11). Clinical symptomatology during the admission and angiographic findings at 1-month follow-up were retrospectively reviewed. Rates of collateralization or recanalization of the cystic artery were compared, as well as the frequency of postprocedural abdominal pain and need for cholecystectomy.ResultsTechnical success was achieved in all patients, and there were no procedural complications related to cystic artery embolization. Of the 11 coil-embolized patients, 5 (45%) demonstrated collateralization of the cystic artery at 1 month, and 1 (9%) demonstrated recanalization of the cystic artery. Of the 35 Gelfoam-embolized cases, 2 (6%) had collateralized at 1 month, and 14 (40%) had recanalized. Two patients (one from each group) had self-limited right upper quadrant pain after the procedure, and one patient in the coil embolization group required cholecystectomy.ConclusionProximal cystic artery embolization is safe and feasible and may be performed during liver-directed embolotherapy to minimize the exposure of the gallbladder to particulate, chemoembolic, or radioembolic agents