782 research outputs found

    Water Quality Sampling, Analysis and Annual Load Determinations for TSS, Nitrogen and Phosphorus at the L\u27Anguille River Near Palestine 2005 Annual Report

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    A water quality sampling station was installed at the L’Anguille River near Palestine in 2003. This station is coordinated with a USGS gauging station at the same location. This station is instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus in the River. The L’Anguille River was listed on Arkansas\u27 1998 (listed in later reports?) 303d list as impaired from sediment (turbidity). The L’Anguille River was the second stream to have total maximum daily loads (TMDL) determined in Arkansas. Accurate determination of stream nutrients and sediment is critical for future determinations of TMDLs, effectiveness of best management practices and trends in water quality

    Cost-effectiveness of dapagliflozin for patients with heart failure across the spectrum of ejection fraction:A pooled analysis of DAPA-HF and DELIVER data

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    Aim: To assess the cost-effectiveness of dapagliflozin in addition to usual care, compared with usual care alone, in a large population of patients with heart failure (HF), spanning the full range of left ventricular ejection fraction (LVEF). Methods and results: Patient-level data were pooled from HF trials (DAPA-HF, DELIVER) to generate a population including HF with reduced, mildly reduced and preserved LVEF, to increase statistical power and enable exploration of interactions among LVEF, renal function and N-terminal pro-B-type natriuretic peptide levels, as they are relevant determinants of health status in this population. Survival and HF recurrent event risk equations were derived and applied to a lifetime horizon Markov model with health states defined by Kansas City Cardiomyopathy Questionnaire total symptom score quartiles; costs and utilities were in the UK setting. The base case incremental cost-effectiveness ratio (ICER) was £6470 per quality-adjusted life year (QALY) gained, well below the UK willingness-to-pay (WTP) threshold of £20 000/QALY gained. In interaction sensitivity analyses, the highest ICER was observed for elderly patients with preserved LVEF (£16 624/QALY gained), and ranged to a region of dominance (increased QALYs, decreased costs) for patients with poorer renal function and reduced/mildly reduced LVEF. Results across the patient characteristic interaction plane were mostly between £5000 and £10 000/QALY gained. Conclusions: Dapagliflozin plus usual care, versus usual care alone, yielded results well below the WTP threshold for the UK across a heterogeneous population of patients with HF including the full spectrum of LVEF, and is likely a cost-effective intervention.</p

    Cost-effectiveness of dapagliflozin for patients with heart failure across the spectrum of ejection fraction:A pooled analysis of DAPA-HF and DELIVER data

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    Aim: To assess the cost-effectiveness of dapagliflozin in addition to usual care, compared with usual care alone, in a large population of patients with heart failure (HF), spanning the full range of left ventricular ejection fraction (LVEF). Methods and results: Patient-level data were pooled from HF trials (DAPA-HF, DELIVER) to generate a population including HF with reduced, mildly reduced and preserved LVEF, to increase statistical power and enable exploration of interactions among LVEF, renal function and N-terminal pro-B-type natriuretic peptide levels, as they are relevant determinants of health status in this population. Survival and HF recurrent event risk equations were derived and applied to a lifetime horizon Markov model with health states defined by Kansas City Cardiomyopathy Questionnaire total symptom score quartiles; costs and utilities were in the UK setting. The base case incremental cost-effectiveness ratio (ICER) was £6470 per quality-adjusted life year (QALY) gained, well below the UK willingness-to-pay (WTP) threshold of £20 000/QALY gained. In interaction sensitivity analyses, the highest ICER was observed for elderly patients with preserved LVEF (£16 624/QALY gained), and ranged to a region of dominance (increased QALYs, decreased costs) for patients with poorer renal function and reduced/mildly reduced LVEF. Results across the patient characteristic interaction plane were mostly between £5000 and £10 000/QALY gained. Conclusions: Dapagliflozin plus usual care, versus usual care alone, yielded results well below the WTP threshold for the UK across a heterogeneous population of patients with HF including the full spectrum of LVEF, and is likely a cost-effective intervention.</p

    Mass coupling and Q1ofimpuritylimitednormalQ^{-1} of impurity-limited normal ^3$He in a torsion pendulum

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    We present results of the Q1Q^{-1} and period shift, ΔP\Delta P, for 3^3He confined in a 98% nominal open aerogel on a torsion pendulum. The aerogel is compressed uniaxially by 10% along a direction aligned to the torsion pendulum axis and was grown within a 400 μ\mum tall pancake (after compression) similar to an Andronikashvili geometry. The result is a high QQ pendulum able to resolve Q1Q^{-1} and mass coupling of the impurity-limited 3^3He over the whole temperature range. After measuring the empty cell background, we filled the cell above the critical point and observe a temperature dependent period shift, ΔP\Delta P, between 100 mK and 3 mK that is 2.9% of the period shift (after filling) at 100 mK. The Q1Q^{-1} due to the 3^3He decreases by an order of magnitude between 100 mK and 3 mK at a pressure of 0.14±0.030.14\pm0.03 bar. We compare the observable quantities to the corresponding calculated Q1Q^{-1} and period shift for bulk 3^3He.Comment: 8 pages, 3 figure

    A global model of malaria climate sensitivity: Comparing malaria response to historic climate data based on simulation and officially reported malaria incidence

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    Background: The role of the Anopheles vector in malaria transmission and the effect of climate on Anopheles populations are well established. Models of the impact of climate change on the global malaria burden now have access to high-resolution climate data, but malaria surveillance data tends to be less precise, making model calibration problematic. Measurement of malaria response to fluctuations in climate variables offers a way to address these difficulties. Given the demonstrated sensitivity of malaria transmission to vector capacity, this work tests response functions to fluctuations in land surface temperature and precipitation. Methods. This study of regional sensitivity of malaria incidence to year-to-year climate variations used an extended Macdonald Ross compartmental disease model (to compute malaria incidence) built on top of a global Anopheles vector capacity model (based on 10years of satellite climate data). The predicted incidence was compared with estimates from the World Health Organization and the Malaria Atlas. The models and denominator data used are freely available through the Eclipse Foundations Spatiotemporal Epidemiological Modeller (STEM). Results: Although the absolute scale factor relating reported malaria to absolute incidence is uncertain, there is a positive correlation between predicted and reported year-to-year variation in malaria burden with an averaged root mean square (RMS) error of 25% comparing normalized incidence across 86 countries. Based on this, the proposed measure of sensitivity of malaria to variations in climate variables indicates locations where malaria is most likely to increase or decrease in response to specific climate factors. Bootstrapping measures the increased uncertainty in predicting malaria sensitivity when reporting is restricted to national level and an annual basis. Results indicate a potential 20x improvement in accuracy if data were available at the level ISO 3166-2 national subdivisions and with monthly time sampling. Conclusions: The high spatial resolution possible with state-of-the-art numerical models can identify regions most likely to require intervention due to climate changes. Higher-resolution surveillance data can provide a better understanding of how climate fluctuations affect malaria incidence and improve predictions. An open-source modelling framework, such as STEM, can be a valuable tool for the scientific community and provide a collaborative platform for developing such models

    Effects of Pore Walls and Randomness on Phase Transitions in Porous Media

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    We study spin models within the mean field approximation to elucidate the topology of the phase diagrams of systems modeling the liquid-vapor transition and the separation of He3^3--He4^4 mixtures in periodic porous media. These topologies are found to be identical to those of the corresponding random field and random anisotropy spin systems with a bimodal distribution of the randomness. Our results suggest that the presence of walls (periodic or otherwise) are a key factor determining the nature of the phase diagram in porous media.Comment: REVTeX, 11 eps figures, to appear in Phys. Rev.

    Observing Supermassive Black Holes across cosmic time: from phenomenology to physics

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    In the last decade, a combination of high sensitivity, high spatial resolution observations and of coordinated multi-wavelength surveys has revolutionized our view of extra-galactic black hole (BH) astrophysics. We now know that supermassive black holes reside in the nuclei of almost every galaxy, grow over cosmological times by accreting matter, interact and merge with each other, and in the process liberate enormous amounts of energy that influence dramatically the evolution of the surrounding gas and stars, providing a powerful self-regulatory mechanism for galaxy formation. The different energetic phenomena associated to growing black holes and Active Galactic Nuclei (AGN), their cosmological evolution and the observational techniques used to unveil them, are the subject of this chapter. In particular, I will focus my attention on the connection between the theory of high-energy astrophysical processes giving rise to the observed emission in AGN, the observable imprints they leave at different wavelengths, and the methods used to uncover them in a statistically robust way. I will show how such a combined effort of theorists and observers have led us to unveil most of the SMBH growth over a large fraction of the age of the Universe, but that nagging uncertainties remain, preventing us from fully understating the exact role of black holes in the complex process of galaxy and large-scale structure formation, assembly and evolution.Comment: 46 pages, 21 figures. This review article appears as a chapter in the book: "Astrophysical Black Holes", Haardt, F., Gorini, V., Moschella, U and Treves A. (Eds), 2015, Springer International Publishing AG, Cha

    Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

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    We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011
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