443 research outputs found

    Probably Safe or Live

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    This paper presents a formal characterisation of safety and liveness properties \`a la Alpern and Schneider for fully probabilistic systems. As for the classical setting, it is established that any (probabilistic tree) property is equivalent to a conjunction of a safety and liveness property. A simple algorithm is provided to obtain such property decomposition for flat probabilistic CTL (PCTL). A safe fragment of PCTL is identified that provides a sound and complete characterisation of safety properties. For liveness properties, we provide two PCTL fragments, a sound and a complete one. We show that safety properties only have finite counterexamples, whereas liveness properties have none. We compare our characterisation for qualitative properties with the one for branching time properties by Manolios and Trefler, and present sound and complete PCTL fragments for characterising the notions of strong safety and absolute liveness coined by Sistla

    Plasmas and Controlled Nuclear Fusion

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    Contains reports on two research projects.U. S. Atomic Energy Commission (Contract AT(11-1)-3070

    CO2 removal with enhanced weathering and ocean alkalinity enhancement: potential risks and co-benefits for marine pelagic ecosystems

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    Humankind will need to remove hundreds of gigatons of carbon dioxide (CO2) from the atmosphere by the end of the twenty-first century to keep global warming below 2°C within the constraints of the global carbon budget. However, so far it is unclear if and how this could be achieved. A widely recognized idea is to accelerate weathering reactions of minerals that consume CO2 when they dissolve. Acceleration could be realized by pulverizing and distributing gigatons of these minerals onto land (termed “enhanced weathering (EW)”) or sea (termed “ocean alkalinity enhancement (OAE)”) thereby largely increasing their reactive surfaces. However, the desired consumption of atmospheric CO2 during dissolution would inevitably be accompanied by a release of mineral dissolution products (alkalinity, Si, Ca, Mg, Fe, Ni, and maybe others). Here, we approximate their maximum additions to assess potential consequences for pelagic communities (mainly primary producers) and the biogeochemical fluxes they control. Based on this assessment, we tentatively qualify the potential to induce positive and/or negative side effects to be high for Fe, Ni, Si, intermediate for alkalinity, and low for Ca and Mg. However, perturbation potentials are always higher at perturbation hotspots and would be different for EW than for OAE. Furthermore, ecological/biogeochemical consequences of EW/OAE largely depend on the minerals used. We hypothesize that mainly calcifiers would profit in a scheme where CaCO3 derivatives would be used due to beneficial changes in carbonate chemistry. Figuratively, this may turn the blue ocean into a white(r) ocean. When using silicates, the release of additional Si, Fe and Ni could benefit silicifiers and N2-fixers (cyanobacteria) and increase ocean productivity ultimately turning the blue ocean into a green(er) ocean. These considerations call for dedicated research to assess risks and co-benefits of mineral dissolution products on marine and other environments. Indeed, both EW and OAE could become important tools to realize CO2 removal at the planetary scale but associated risks and/or co-benefits should be revealed before deciding on their implementation

    Explicit modelling of resources for multi-agent microservices using the cartago framework

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    The 19th International Conference on Autonomous Agents and Multiagent Systems (AAMS 2020), Auckland, New Zealand, 9-13 May 2020This paper describes the first agent programming language agnostic implementation of the Multi-Agent MicroServices (MAMS) model - an approach to integrating agents within microservices-based architectures where agents expose aspects of their state as virtual resources, realised as CArtAgO artifacts, that are externally accessible through REpresentational State Transfer (REST).Science Foundation Irelan

    MAMS: Multi-Agent MicroServices

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    The 2019 World Wide Web Conference (WWW'19), San Francisco, United States of America, 13-17 May 2019This paper explores the intersection between microservices and Multi-Agent Systems (MAS), introducing the notion of a new approach to building MAS known as Multi-Agent MicroServices (MAMS). Our approach is illustrated through a worked example of a Vickrey Auction implemented as a microservice.Science Foundation IrelandOrigin Enterprises Pl

    Prognostic value of neutrophil gelatinase-associated lipocalin in acute heart failure

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    Background: The identification of patients at risk for worse outcome is still a challenge. We hypothesized that cystatin C, a marker of renal function, and neutrophil gelatinase-associated lipocalin (NGAL), a marker of acute renal injury, would have a role in the prognostic stratification of these patients. Methods: We prospectively evaluated 121 patients admitted for acute HF. Serum NGAL and cystatin C levels were measured on the first morning after admission. The outcome measures used were the occurrence of death from all causes, and the combined endpoint defined as the first occurrence of either death or hospital admission. Patients were followed for up to 3 months. Results: The variables associated with a higher occurrence of death in a univariate approach were older age and higher levels of BNP, cystatin C and NGAL, and those associated with the occurrence of the combined endpoint were older age, Diabetes mellitus, lower GFR, type 1 cardio-renal syndrome, BNP, cystatin C and NGAL. BNP and NGAL remained independent predictors of the occurrence of both all-cause death and the combined endpoint. NGAL levels in the 75th percentile (> 167.5 ng/mL) were associated with a 2.7-fold increase in the risk of death and a 2.9-fold increase in the risk of the first occurrence of either death or hospitalization. Conclusions: Serum NGAL, a marker of acute renal injury, is an independent predictor of worse short term prognosis in patients with acute HF. This suggests a role of renal damage, apart from renal function, in the prognosis of these patients

    Is the Shroud of Turin in Relation to the Old Jerusalem Historical Earthquake?

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    Phillips and Hedges suggested, in the scientific magazine Nature (1989), that neutron radiation could be liable of a wrong radiocarbon dating, while proton radiation could be responsible of the Shroud body image formation. On the other hand, no plausible physical reason has been proposed so far to explain the radiation source origin, and its effects on the linen fibres. However, some recent studies, carried out by the first author and his Team at the Laboratory of Fracture Mechanics of the Politecnico di Torino, found that it is possible to generate neutron emissions from very brittle rock specimens in compression through piezonuclear fission reactions. Analogously, neutron flux increments, in correspondence to seismic activity, should be a result of the same reactions. A group of Russian scientists measured a neutron flux exceeding the background level by three orders of magnitude in correspondence to rather appreciable earthquakes (4th degree in Richter Scale). The authors consider the possibility that neutron emissions by earthquakes could have induced the image formation on Shroud linen fibres, trough thermal neutron capture by Nitrogen nuclei, and provided a wrong radiocarbon dating due to an increment in C(14,6)content. Let us consider that, although the calculated integral flux of 10^13 neutrons per square centimetre is 10 times greater than the cancer therapy dose, nevertheless it is100 times smaller than the lethal dose.Comment: 13 pages, 1 figur
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