250 research outputs found

    Out of sight, not out of mind: developments in economic models of groundwater management

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    Dynamic models of natural resource management have been applied to groundwater for decades, incorporating at least two inescapable aspects: first, since groundwater stocks are carried over to future periods, dynamic analysis is essential and any costs and benefits included in the analysis will require discounting; second, the positive and normative aspects of management must be clarified at the outset. The difference is fundamental even if the results of the two model types sometimes turn out to be fairly close. A whole strand of literature has been preoccupied with the question of whether policy interventions at least have the potential of improving groundwater management in a meaningful sense. However, given the well-documented parlous state of many aquifers around the world today, the focus has mostly shifted from debating whether or not intervention is worthwhile to identifying the relevant features of complex groundwater systems, designing better policies and facilitating their successful implementation. We survey developments in economic models relevant to groundwater management, focusing especially on the depiction of uncertainty and on the different methods applied to estimate the total economic value of groundwater.info:eu-repo/semantics/acceptedVersio

    A Novel HydroEconomic - Econometric Approach for Integrated Transboundary Water Management Under Uncertainty

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    The optimal management of scarce transboundary water resources among competitive users is expected to be challenged by the effects of climate change on water availability. The multiple economic and social implications, including conflicts between neighbouring countries, as well as competitive sectors within each country are difficult to estimate and predict, to inform policy-making. In this paper, this problem is approached as a stochastic multistage dynamic game: we develop and apply a novel framework for assessing and evaluating different international strategies regarding transboundary water resources use, under conditions of hydrological uncertainty. The Omo-Turkana transboundary basin in Africa is used as a case study application, since it increasingly faces the above challenges, including the international tension between Kenya and Ethiopia and each individual country’s multi-sectoral competition for water use. The mathematical framework combines a hydro-economic model (water balance, water costs and benefits), and an econometric model (production functions and water demand curves) which are tested under cooperative and non-cooperative conditions (Stackelberg “leader–follower” game). The results show the cross-country and cross-sectoral water use—economic trade-offs, the future water availability for every game case, the sector-specific production function estimations (including residential, agriculture, energy, mining, tourism sectors), with nonparametric treatment, allowing for technical inefficiency in production and autocorrelated Total Factor Productivity, providing thus a more realistic simulation. Cooperation between the two countries is the most beneficial case for future water availability and economic growth. The study presents a replicable, sophisticated modelling framework, for holistic transboundary water management

    Unstationary film model for the determination of absolute gas-liquid kinetic rate constants: ozonation of Acid Red 27, Acid Orange 7, and Acid Blue 129

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    A method for the determination of absolute kinetic rate constants is proposed using an unstationary film model. This methodology avoids the experimental determination of parameters like the enhancement factor or the Hatta number which are usually model-dependent. The mathematical model is general for gas-liquid systems with irreversible second order reactions. An optimization procedure based on artificial neural networks is used to estimate the initial guess of the parameters and the subsequent application of Gauss-Newton algorithm for the final nonlinear parameter estimation. The model is tested with the ozonation reaction of Acid Red 27, Acid Orange 7 and Acid Blue 129. The second-order kinetic rate constants for the direct reaction with O3 are 1615±93, 609±83, and 49±2M−1s−1, respectivelyJF acknowledges the support of the doctoral fellowship from the Universitat Politecnica de Valencia (UPV-PAID-FPI-2010-04).Ferre Aracil, J.; Cardona Navarrete, SC.; López Pérez, MF.; Abad Sempere, A.; Navarro-Laboulais, J. (2013). Unstationary film model for the determination of absolute gas-liquid kinetic rate constants: ozonation of Acid Red 27, Acid Orange 7, and Acid Blue 129. Ozone: Science and Engineering. 35(6):423-437. https://doi.org/10.1080/01919512.2013.815104S423437356Biń, A. K. (2006). Ozone Solubility in Liquids. Ozone: Science & Engineering, 28(2), 67-75. doi:10.1080/01919510600558635Cardona, S. C., López, F., Abad, A., & Navarro-Laboulais, J. (2010). On bubble column reactor design for the determination of kinetic rate constants in gas-liquid systems. The Canadian Journal of Chemical Engineering, 88(4), 491-502. doi:10.1002/cjce.20327Chang, C. 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Journal of Chemical & Engineering Data, 12(1), 111-115. doi:10.1021/je60032a036Gerlach, D., Alleborn, N., Buwa, V., & Durst, F. (2007). Numerical simulation of periodic bubble formation at a submerged orifice with constant gas flow rate. Chemical Engineering Science, 62(7), 2109-2125. doi:10.1016/j.ces.2006.12.061Glasscock, D. A., & Rochelle, G. T. (1989). Numerical simulation of theories for gas absorption with chemical reaction. AIChE Journal, 35(8), 1271-1281. doi:10.1002/aic.690350806Gomes, A. C., Nunes, J. C., & Simões, R. M. S. (2010). Determination of fast ozone oxidation rate for textile dyes by using a continuous quench-flow system. Journal of Hazardous Materials, 178(1-3), 57-65. doi:10.1016/j.jhazmat.2010.01.043Gupta, P., Al-Dahhan, M. H., Duduković, M. P., & Mills, P. L. (2000). A novel signal filtering methodology for obtaining liquid phase tracer responses from conductivity probes. Flow Measurement and Instrumentation, 11(2), 123-131. doi:10.1016/s0955-5986(99)00025-4Hoigné, J., & Bader, H. (1983). Rate constants of reactions of ozone with organic and inorganic compounds in water—I. Water Research, 17(2), 173-183. doi:10.1016/0043-1354(83)90098-2Jamialahmadi, M., Zehtaban, M. R., Müller-Steinhagen, H., Sarrafi, A., & Smith, J. M. (2001). Study of Bubble Formation Under Constant Flow Conditions. Chemical Engineering Research and Design, 79(5), 523-532. doi:10.1205/02638760152424299Johnson, P. N., & Davis, R. A. (1996). Diffusivity of Ozone in Water. Journal of Chemical & Engineering Data, 41(6), 1485-1487. doi:10.1021/je9602125King, C. J. (1966). Turbulent Liquid Phase Mass Transfer at Free Gas-Liquid Interface. Industrial & Engineering Chemistry Fundamentals, 5(1), 1-8. doi:10.1021/i160017a001Ledakowicz, S., Maciejewska, R., Perkowski, J., & Bin, A. (2001). Ozonation of Reactive Blue 81 in the bubble column. Water Science and Technology, 44(5), 47-52. doi:10.2166/wst.2001.0248Lewis, W. K., & Whitman, W. G. (1924). Principles of Gas Absorption. Industrial & Engineering Chemistry, 16(12), 1215-1220. doi:10.1021/ie50180a002Lopez, A., Benbelkacem, H., Pic, J. ‐S., & Debellefontaine, H. (2004). Oxidation pathways for ozonation of azo dyes in a semi‐batch reactor: A kinetic parameters approach. Environmental Technology, 25(3), 311-321. doi:10.1080/09593330409355465Meldon, J. H., Olawoyin, O. O., & Bonanno, D. (2007). Analysis of Mass Transfer with Reversible Chemical Reaction†. Industrial & Engineering Chemistry Research, 46(19), 6140-6146. doi:10.1021/ie0705397Navarro-Laboulais, J., Cardona, S. C., Torregrosa, J. I., Abad, A., & López, F. (2006). Structural identifiability analysis of the dynamic gas–liquid film model. AIChE Journal, 52(8), 2851-2863. doi:10.1002/aic.10901Navarro-Laboulais, J., Cardona, S. C., Torregrosa, J. I., Abad, A., & López, F. (2008). Practical identifiability analysis in dynamic gas–liquid reactors. Computers & Chemical Engineering, 32(10), 2382-2394. doi:10.1016/j.compchemeng.2007.12.004Rapp, T., & Wiesmann, U. (2007). Ozonation of C.I. Reactive Black 5 and Indigo. Ozone: Science & Engineering, 29(6), 493-502. doi:10.1080/01919510701617959Tanaka, M., Girard, G., Davis, R., Peuto, A., & Bignell, N. (2001). Recommended table for the density of water between 0  C and 40  C based on recent experimental reports. Metrologia, 38(4), 301-309. doi:10.1088/0026-1394/38/4/3Tizaoui, C., & Grima, N. (2011). Kinetics of the ozone oxidation of Reactive Orange 16 azo-dye in aqueous solution. Chemical Engineering Journal, 173(2), 463-473. doi:10.1016/j.cej.2011.08.014Von Gunten, U. (2003). Ozonation of drinking water: Part I. Oxidation kinetics and product formation. Water Research, 37(7), 1443-1467. doi:10.1016/s0043-1354(02)00457-

    On identifiability for chemical systems from measurable variables

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s10910-013-0149-4The dynamics of the composition of chemical species in reacting systems can be characterized by a set of autonomous differential equations derived from mass conservation principles and some elementary hypothesis related to chemical reactivity. These sets of ordinary differential equations are basically non-linear, their complexity grows as much increases the number of substances present in the reacting media an can be characterized by a set of phenomenological constants which contains all the relevant information about the physical system. The determination of these kinetic constants is critical for the design or control of chemical systems from a technological point of view but the non-linear nature of the equations implies that there are hidden correlations between the parameters which maybe can be revealed with a identifiability analysis.This work has been partially supported by MTM2010-18228.Cantó Colomina, B.; Coll, C.; Sánchez, E.; Cardona Navarrete, SC.; Navarro-Laboulais, J. (2014). On identifiability for chemical systems from measurable variables. Journal of Mathematical Chemistry. 52(4):1023-1035. https://doi.org/10.1007/s10910-013-0149-4S10231035524M.J. Almendral, A. Alonso, M.S. Fuentes, Development of new methodologies for on-line determination of the bromate. J. Environ. Monit. 11, 1381–1388 (2009)A. Ben-Zvi, P.J. McLellan, K.B. McAuley, Identifiability of linear time-invariant differential-algebraic systems. I. The generalized Markov parameter approach. Ind. Eng. Chem. Res. 42, 6607–6618 (2003)T.P. Bonacquisti, A drinking water utility’s perspective on bromide, bromate, and ozonation. Toxicology 221, 145–148 (2006)R. Butler, A. Godley, L. Lytton, E. Cartmell, Bromate environmental contamination: review of impact and possible treatment. Crit. Rev. Environ. Sci. Tech. 35, 193–217 (2005)R. Butler, L. Lytton, A.R. Godley, I.E. Tothill, E. Cartmell, Bromate analysis in groundwater and wastewater samples. J. Environ. Monit. 7, 999–1006 (2005)B. Cantó, S.C. Cardona, C. Coll, J. Navarro-Laboulais, E. Sánchez, Dynamic optimization of a gas-liquid reactor. J. Math. Chem. 50, 381–393 (2012)B. Cantó, C. Coll and E. Sánchez, Identifiability of a class of discretized linear partial differential algebraic equations, Math. Problems Eng. 2011, 1–12 (2011)A. Constantinides, N. Mostoufi, Numerical Methods for Chemical Engineers with MATLAB Applications, Alkis Constantinides and Navid Mostoufi, Upper Saddle River (Prentice Hall, New Jersey, 1999)P. Englezos, N. Kalogerakis, Applied Parameter Estimation for Chemical Engineers (Marcel Dekker, New York, 2001)U. von Gunten, Ozonation of drinking water. Part II. Disinfection and by-product formation in presence of bromide, iodide or chlorine. Water Res. 37, 1469–1487 (2003)B. Legube, B. Parinet, K. Gelinet, F. Berne, J-Ph Croue, Modeling of bromate formation by ozonation of surface waters in drinking water treatment. Water Res. 38, 2185–2195 (2004)Q. Liu, L.M. Schurter, C.E. Muller, S. Aloisio, J.S. Francisco, D.W. Margerum, Kinetics and mechanisms of aqueous ozone reactions with bromide, sulfite, hydrogen sulfite, iodide, and nitrite ions. Inorg. Chem. 40, 4436–4442 (2001)J.B. Rawling, J.G. Ekerdt, Chemical Reactor Analysis and Design Fundamentals (Nob Hill Pub, Madison, 2002)W.E. Stewart, M. Caracotsios, Computer Aided Modelling of Reactive Systems (John Wiley and Sons, New York, 2008)P. Westerhoff, R. Song, G. Amy, R. Minear, Numerical kinetic models for bromide oxidation to bromine and bromate. Water Res. 32, 1687–1699 (1998)World Health Organization, Bromate in Drinking-water, Document WHO/SDE/WSH/05.08/78, http://www.who.int/water_sanitation_health/dwq/chemicals/en/ (accesed 26/07/12

    Measurement of nuclear effects in neutrino-argon interactions using generalized kinematic imbalance variables with the MicroBooNE detector

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    We present a set of new generalized kinematic imbalance variables that can be measured in neutrino scattering. These variables extend previous measurements of kinematic imbalance on the transverse plane and are more sensitive to modeling of nuclear effects. We demonstrate the enhanced power of these variables using simulation and then use the MicroBooNE detector to measure them for the first time. We report flux-integrated single- and double-differential measurements of charged-current muon neutrino scattering on argon using a topology with one muon and one proton in the final state as a function of these novel kinematic imbalance variables. These measurements allow us to demonstrate that the treatment of charged current quasielastic interactions in genie version 2 is inadequate to describe data. Further, they reveal tensions with more modern generator predictions particularly in regions of phase space where final state interactions are important

    2021 Thalassaemia International Federation Guidelines for the Management of Transfusion-dependent Thalassemia

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    Beta-thalassemia and particularly its transfusion-dependent form (TDT) is a demanding clinical condition, requiring life-long care and follow-up, ideally in specialized centers and by multidisciplinary teams of experts. Despite the significant progress in TDT diagnosis and treatment over the past decades that has dramatically improved patients' prognosis, its management remains challenging. On one hand, diagnostic and therapeutic advances are not equally applied to all patients across the world, particularly in several high-prevalence eastern regions. On the other, healthcare systems in low-prevalence western countries that have recently received large numbers of migrant thalassemia patients, were not ready to address patients' special needs. Thalassaemia International Federation (TIF), a global patient-driven umbrella federation with 232 member-associations in 62 countries, strives for equal access to quality care for all patients suffering from thalassemia or other hemoglobinopathies in every part of the world by promoting education, research, awareness, and advocacy. One of TIF's main actions is the development and dissemination of clinical practice guidelines for the management of these patients. In 2021, the fourth edition of TIF's guidelines for the management of TDT was published. The full text provides detailed information on the management of TDT patients and the clinical presentation, pathophysiology, diagnostic approach, and treatment of disease complications or other clinical entities that may occur in these patients, while also covering relevant psychosocial and organizational issues. The present document is a summary of the 2021 TIF guidelines for TDT that focuses mainly on clinical practice issues and recommendations

    Search for heavy neutral leptons in electron-positron and neutral-pion final states with the MicroBooNE detector

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    We present the first search for heavy neutral leptons (HNL) decaying into νe+e\nu e^+e^- or νπ0\nu\pi^0 final states in a liquid-argon time projection chamber using data collected with the MicroBooNE detector. The data were recorded synchronously with the NuMI neutrino beam from Fermilab's Main Injector corresponding to a total exposure of 7.01×10207.01 \times 10^{20} protons on target. We set upper limits at the 90%90\% confidence level on the mixing parameter Uμ42\lvert U_{\mu 4}\rvert^2 in the mass ranges 10mHNL15010\le m_{\rm HNL}\le 150 MeV for the νe+e\nu e^+e^- channel and 150mHNL245150\le m_{\rm HNL}\le 245 MeV for the νπ0\nu\pi^0 channel, assuming Ue42=Uτ42=0\lvert U_{e 4}\rvert^2 = \lvert U_{\tau 4}\rvert^2 = 0. These limits represent the most stringent constraints in the mass range 35<mHNL<17535<m_{\rm HNL}<175 MeV and the first constraints from a direct search for νπ0\nu\pi^0 decays.Comment: Version as accepted by Physical Review Letters, some presentational changes and updated references, no changes to result
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