5,272 research outputs found
Run-Time Selection of Coordination Mechanisms in Multi-Agent Systems
This paper presents a framework that enables autonomous agents to dynamically select the mechanism they employ in order to coordinate their inter-related activities. Adopting this framework means coordination mechanisms move from the realm of being imposed upon the system at design time, to something that the agents select at run-time in order to fit their prevailing circumstances and their current coordination needs. Empirical analysis is used to evaluate the effect of various design alternatives for the agent's decision making mechanisms and for the coordination mechanisms themselves
Thermal energy storage material thermophysical property measurement and heat transfer impact
The thermophysical properties of salts having potential for thermal energy storage to provide peaking energy in conventional electric utility power plants were investigated. The power plants studied were the pressurized water reactor, boiling water reactor, supercritical steam reactor, and high temperature gas reactor. The salts considered were LiNO3, 63LiOH/37 LiCl eutectic, LiOH, and Na2B4O7. The thermal conductivity, specific heat (including latent heat of fusion), and density of each salt were measured for a temperature range of at least + or - 100 K of the measured melting point. Measurements were made with both reagent and commercial grades of each salt
Playas of inland Australia
[Abstract] Playas, mostly in the form of salinas, are characteristic of the Australian arid zone. Many are
associated with lunettes in sebkha complexes or assemblages and can be attributed to the deflation
of bare alluvial flats. Many playas are structurally controlled. Lake Eyre, for example, occupies
a downfaulted segment of the crust, and many other playas large and small are associated with
faults. Lakes Frome, Callabonna, Blanche, and Gregory each displays a linear shoreline, but also
and arguably, all are located on a regional structural arc. Lake Gairdner occupies a valley probably
blocked by faulting. Others may be caused by preferential weathering along fracture zones, some
linear but others arcuate. Many salinas are developed in dismembered rivers channels, the position
and pattern of which are structurally determined. But many owe their existence to the interaction
of several of these factors. The various salts precipitated in playas constitute a significant resource,
regional and local, past, present and future
Quantitative acoustic analysis of the vocal repertoire of the golden rocket frog (\u3ci\u3eAnomaloglossus beebei\u3c/i\u3e)
This study describes the vocal repertoire of the Guyanan golden rocket frog, Anomaloglossus beebei, a bromeliad specialist with biparental care. Using multivariate analyses of nine call properties, as well as the occurrence of nonlinear phenomena, three signal types were distinguished—advertisement, courtship, and aggressive calls. Although all three call types were composed of a short series of rapidly repeated pulses, advertisement calls were produced at higher amplitudes and had longer pulse durations than both courtship calls and aggressive calls. Courtship calls exhibited lower dominant frequencies than both advertisement and aggressive calls, which had similar dominant frequencies. Aggressive calls had more pulses per call, had longer intervals between calls, and occasionally contained one or two introductory pulses preceding the pulsed call. Several acoustic properties predicted aspects of the signaler\u27s body size and condition. Our study demonstrates the reliability of human observers to differentiate the multiple call types of A. beebei based on hearing calls and observing the social context in which they are produced under field conditions
Comparison between SELEX and single-step selection for the identification of bivalent aptamers for thrombin
The identification of bivalent aptamers for thrombin by SELEX and single-step selection are compared using next generation (massively parallel) sequencing and motif finding informatics. Results show that similar aptamers are identified by both methods
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015 : a systematic analysis for the Global Burden of Disease Study 2015
Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defi ned criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted causespecifi c DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient defi ciencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden
School-based Understanding of Human Rights in Four Countries: A Commonwealth Study
Teaching/Communication/Extension/Profession,
Perceptions of pre-exposure prophylaxis (PrEP) among HIV-negative and HIV-positive men who have sex with men (MSM)
Pre-exposure prophylaxis (PrEP) is a novel bio-medical HIV prevention option for individuals at high risk of HIV exposure. This qualitative interview study explores perceptions and understandings of PrEP among a sample of 20 HIV-negative and HIV-positive men who have sex with men (MSM) in the UK, where there is a debate about the feasibility of offering PrEP on the NHS. Data were analysed using qualitative thematic analysis and social representations theory from social psychology. The following three themes are discussed: (1) uncertainty and fear, (2) managing relationships with others, and (3) stigma and categorization. HIV-negative interviewees generally perceived PrEP as a risky solution for “high risk” individuals, while HIV-positive individuals regarded it as potentially enhancing interpersonal relations between serodiscordant partners. Social stigma overwhelmingly underpinned individuals’ perceptions of PrEP. This might inhibit access to PrEP among those who might benefit most from it, thereby undermining HIV prevention efforts
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