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We have implemented and deployed an access control mechanism that uses digitally-signed certificates to define and enforce an access policy for a set of distributed resources that have multiple, independent and geographically dispersed stakeholders. The stakeholders assert their access requirements in use-condition certificates and designate those trusted(More)
We describe a methodology that enables the real-time diagnosis of performance problems in complex high-performance distributed systems. The methodology includes tools for generating precision event logs that can be used to provide detailed end-to-end application and system level monitoring; a Java agent-based system for managing the large amount of logging(More)
Information Power Grid (IPG) is the name of NASA's project to build a fully distributed computing and data management environment – a Grid. The IPG project has near, medium, and long-term goals that represent a continuum of engineering, development, and research topics. The overall goal is to provide the NASA scientific and engineering communities a(More)
We have observed many focal dilatations or very small aneurysms in terminal arterioles and capillaries of 4 of 5 patients and 6 dogs who had recently undergone cardiopulmonary bypass. A smaller number of sausagelike dilatations distended medium-sized arterioles. Two other patients had a small number of the same microvascular changes following proximal(More)
With the advent of service sensitive applications such as remote controlled experiments, time constrained massive data transfers, and video-conferencing, it has become apparent that there is a need for the setup of dynamically provisioned, quality of service enabled virtual circuits. The ESnet on-demand secure circuits and advance reservation system(More)
OBJECTIVE The aim was to test the hypothesis that the cardioprotective effects against ischaemic-reperfusion injury of pretreatment with adenosine are mediated in part by activation of ATP sensitive potassium channels (K+ATP channels). METHODS 42 anaesthetised New Zealand White rabbits underwent 30 min coronary occlusion, followed by 2 h reperfusion. Half(More)
In widely distributed systems generally, and in science-oriented Grids in particular, software, CPU time, storage, etc., are treated as " services " – they can be allocated and used with service guarantees that allows them to be integrated into systems that perform complex tasks. Network communication is currently not a service – it is provided, in general,(More)
In two trials, SC White Leghorns were subjected to constant ambient temperatures of 21.1, 29.4, and 35.0 C from 2 to 31 or 32 weeks of age. Weekly measurements were made of body weight, feed efficiency, water consumption, red blood cell count, hemoglobin, hematocrit, total plasma protein, Po2, Pco2, pH, and mortality. It was found that the blood picture(More)
OBJECTIVE Gaseous microemboli during cardiac surgery have been implicated as a potential cause of postoperative neurologic injury. Any monitoring technique that exposes the systemic circulation to atmospheric pressure could introduce gaseous microemboli, causing cerebral microembolization. The incidence of carotid artery gaseous microemboli was studied(More)