Decentralizing water resource management : economic incentives, accountability, and assurance

Private sector involvement and user participation in water resource management are not new, say the authors. They give examples that demonstrate how willing users and the private sector are able to improve water use and play a larger role in water resources management. User participation and private sector involvement, if properly structured, can provide the incentives needed to stabilize and improve the efficiency of irrigation and water supply systems. They can add flexibility, transparency, and accountability and can reduce the state's administrative and financial burden. A 1989 World Bank review of 21 impact evaluations of irrigation projects, for example, found cost recovery to be excellent in those projects in which water management and operations and maintenance had been entrusted to water users. Greater private sector and user participation can effectively increase user responsibility for managing and financing water projects while freeing governments to focus on broader water resource management concerns. The authors provide examples of decentralized water management in developing country water supply and irrigation systems. Governments should: more actively regulate private sector exploitation of groundwater, especially for irrigation; take measures to encourage price competition among private suppliers of water for both domestic and agricultural uses; and play an active role in organizing water user associations, especially for irrigation and rural water supply systems, and in giving them technical assistance. As numerous examples highlight, such activities should be designed to reduce the transaction costs of organizing and to establish a sense of assurance and accountability within the water user community. Once this is done, the community can deal with problems associated with excludability and unwillingness to pay.Water Supply and Sanitation Governance and Institutions,Water and Industry,Water Use,Water Conservation,Town Water Supply and Sanitation

Water Resources Problems in Developing Countries

Resource /Energy Economics and Policy,

Impact of cloud-borne aerosol representation on aerosol direct and indirect effects

International audienceAerosol particles attached to cloud droplets are much more likely to be removed from the atmosphere and are much less efficient at scattering sunlight than if unattached. Models used to estimate direct and indirect effects of aerosols employ a variety of representations of such cloud-borne particles. Here we use a global aerosol model with a relatively complete treatment of cloud-borne particles to estimate the sensitivity of simulated aerosol, cloud and radiation fields to various approximations to the representation of cloud-borne particles. We find that neglecting transport of cloud-borne particles introduces little error, but that diagnosing cloud-borne particles produces global mean biases of 20% and local errors of up to 40% for aerosol, droplet number, and direct and indirect radiative forcing. Aerosol number, aerosol optical depth and droplet number are significantly underestimated in regions and seasons where and when wet removal is primarily by stratiform rather than convective clouds (polar regions during winter), but direct and indirect effects are less biased because of the limited sunlight there and then. A treatment that predicts the total mass concentration of cloud-borne particles for each mode yields smaller errors and runs 20% faster than the complete treatment. The errors are much smaller than current estimates of uncertainty in direct and indirect effects of aerosols, which suggests that the treatment of cloud-borne aerosol is not a significant source of uncertainty in estimates of direct and indirect effects

Effects of carbon dioxide on trapped electrolyte hydrogen-oxygen, alkaline fuel cells

Effects of carbon dioxide on trapped electrolyte hydrogen-oxygen alkaline fuel cell

REDUCING PHOSPHORUS POLLUTION IN THE MINNESOTA RIVER: HOW MUCH IS IT WORTH?

A mail survey was conducted in Minnesota in 1997 to estimate the value of reducing phosphorus levels in the Minnesota River by 40%. The general population survey of river basin residents was designed to gather information about respondents' use of the Minnesota River in addition to their valuation of a hypothetical water quality improvement program. An estimate of the value of a specific recreational site along the River, the Minnesota Valley National Wildlife Refuge, was also obtained. Three distinct models were estimated in this research. The first was a contingent valuation model estimating the willingness to pay (WTP) for water quality improvements in the Minnesota River using only stated preference data. There were two different payment vehicles used in this question, an increase in the state income tax and a water bill surcharge. Respondents' annual mean willingness to pay for a 40% reduction in phosphorus was estimated to be $14.07 using this model and the tax vehicle, while the mean willingness to pay via the water bill surcharge was estimated to be$19.64 annually. The second model utilized stated preference data from respondents along with responses about their actual visit behavior. A panel model was constructed using the responses to three separate questions concerning the value of a 40% reduction in phosphorus pollution and yielded an estimate of $38.88 per year. The final model used only data from the subset of respondents who had actually visited the Minnesota Valley National Wildlife Refuge. The recreational value of a typical trip to the Refuge was estimated to be$28.71 per individual.Environmental Economics and Policy,

Airspace Technology Demonstration 3 (ATD-3): Dynamic Routes for Arrivals in Weather (DRAW) Technology Transfer Document Summary Version 2.0

Airspace Technology Demonstration 3 (ATD-3) is part of NASAs Airspace Operations and Safety Program (AOSP) specifically, its Airspace Technology Demonstrations (ATD) Project. ATD-3 is a multi-year research and development effort which proposes to develop and demonstrate automation technologies and operating concepts that enable air navigation service providers and airspace users to continuously assess weather, winds, traffic, and other information to identify, evaluate, and implement workable opportunities for flight plan route corrections that can result in significant flight time and fuel savings in en route airspace. In order to ensure that the products of this tech-transfer are relevant and useful, NASA has created strong partnerships with the FAA and key industry stakeholders. This summary document and accompanying technology artifacts satisfy the third Research Transition Product (RTP) defined in the Applied Traffic Flow Management (ATFM) Research Transition Team (RTT) Plan, which is Dynamic Routes for Arrivals in Weather (DRAW). This technology transfer consists of artifacts for DRAW Arrival Metering (AM) Operations delivered in June 2018, DRAW AM updates, and DRAW Extended Metering (XM) Operations. Blue highlighting indicates the new or modified deliverables. Some of the artifacts in this technology transfer have distribution restrictions that need to be followed. Distribution information is noted in each section. DRAW is a trajectory-based system that combines the legacy Dynamic Weather Routes (DWR) weather avoidance technology with an arrival-specific rerouting algorithm and arrival scheduler to improve traffic flows on weather-impacted arrival routes into major airports. First, DRAW identifies flights that could be rerouted to more efficient Standard Terminal Arrival Routes (STARs) that may have previously been impacted by weather. Second, when weather is impacting the arrival routing, DRAW proposes simple arrival route corrections that enable aircraft to stay on their flight plan while avoiding weather. The DRAW system proposes reroutes early enough to allow Time Based Flow Management (TBFM) to make the necessary schedule adjustments. As a result, metering operations can be sustained longer and more consistently in the presence of weather because the arrival schedule accounts for the dynamic routing intent of arrival flights to deviate around weather. The first DRAW tech transfer in June 2018 focused on arrival metering operations with the DRAW algorithm implemented in the NASA Center TRACON Automation System (CTAS) automation software. This tech transfer delivery includes updates for DRAW implemented in FAAs TBFM 4.7 automation software and preliminary research into DRAW for XM operations

Computing Fast and Reliable Gravitational Waveforms of Binary Neutron Star Merger Remnants

Gravitational waves have been detected from the inspiral of a binary neutron-star, GW170817, which allowed constraints to be placed on the neutron star equation of state. The equation of state can be further constrained if gravitational waves from a post-merger remnant are detected. Post-merger waveforms are currently generated by numerical-relativity simulations, which are computationally expensive. Here we introduce a hierarchical model trained on numerical-relativity simulations, which can generate reliable post-merger spectra in a fraction of a second. Our spectra have mean fitting factors of 0.95, which compares to fitting factors of 0.76 and 0.85 between different numerical-relativity codes that simulate the same physical system. This method is the first step towards generating large template banks of spectra for use in post-merger detection and parameter estimation.Comment: Submitted to PRL. 6 pages, 4 figure

Numerical modelling of liquid droplet dynamics in microgravity

Microgravity provides ideal experimental conditions for studying highly reactive and under-cooled materials where there is no contact between the sample and the other experimental apparatus. The non-contact conditions allow material properties to be measured from the oscillating liquid droplet response to perturbations. This work investigates the impact of a strong magnetic field on these measurement processes for weakly viscous, electrically conducting droplets. We present numerical results using an axisymmetric model that employs the pseudo-spectral collocation method and a recently developed 3D model. Both numerical models have been developed to solve the equations describing the coupled electromagnetic and fluid flow processes. The models represent the changing surface shape that results from the interaction between forces inside the droplet and the surface tension imposed boundary conditions. The models are used to examine the liquid droplet dynamics in a strong DC magnetic field. In each case the surface shape is decomposed into a superposition of spherical harmonic modes. The oscillation of the individual mode coefficients is then analysed to determine the oscillation frequencies and damping rates that are then compared to the low amplitude solutions predicted by the published analytical asymptotic theory

Ultrasonographic-based predictive factors influencing successful return to racing after superficial digital flexor tendon injuries in flat racehorses: a retrospective cohort study in 469 Thoroughbred racehorses in Hong Kong

Background: Superficial digital flexor tendon (SDFT) injury is an important health and welfare concern in racehorses. It is generally diagnosed with ultrasonography, predictive ultrasonographic features have not been reported. Objectives: To determine ultrasonographic features of forelimb SDFT injury at initial presentation in Thoroughbred racehorses, that could predict a successful return to racing (completing > or = 5 races). Study Design: Retrospective cohort study. Methods: Digitised ultrasonographic images of 469 horses with forelimb SDFT injuries from the Hong Kong Jockey Club (2003-2014) were evaluated, using a previously validated ultrasonographic scoring system. Six ultrasonographic parameters were evaluated (type and extent of the injury, location, echogenicity, cross-sectional area and longitudinal fiber pattern of the maximal injury zone (MIZ)), as well as horse signalment, retirement date and number of races before and after injury. Data was analysed by generalized linear regression with significance at P<0.05. Results: Cases were divided in two groups: 1) For cases of SDFT tendonitis with core lesions, cross-sectional area at the MIZ was the most significant factor determining a successful return to racing (p=0.03). If the lesion was or > or = 50% this decreased to 11-16%. 2) For cases of SDFT tendonitis without a core lesion, longitudinal fiber pattern at the MIZ best predicted a successful return to racing (P=0.002); if the affected longitudinal fiber pattern was or = 75% this decreased to 14%. Main Limitations: Prognostic information may not be applicable to other breeds/disciplines. Conclusions: This is the first study to describe ultrasonographic features of forelimb SDFT injuries at initial presentation that were predictive of successful return to racing. The outcomes will assist with early, evidence-based decisions on prognosis in Thoroughbred racehorses

Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction

This paper describes and evaluates a new framework for modeling kinetic gas-particle partitioning of secondary organic aerosol (SOA) that takes into account diffusion and chemical reaction within the particle phase. The framework uses a combination of (a) an analytical quasi-steady-state treatment for the diffusion–reaction process within the particle phase for fast-reacting organic solutes, and (b) a two-film theory approach for slow- and nonreacting solutes. The framework is amenable for use in regional and global atmospheric models, although it currently awaits specification of the various gas- and particle-phase chemistries and the related physicochemical properties that are important for SOA formation. Here, the new framework is implemented in the computationally efficient Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) to investigate the competitive growth dynamics of the Aitken and accumulation mode particles. Results show that the timescale of SOA partitioning and the associated size distribution dynamics depend on the complex interplay between organic solute volatility, particle-phase bulk diffusivity, and particle-phase reactivity (as exemplified by a pseudo-first-order reaction rate constant), each of which can vary over several orders of magnitude. In general, the timescale of SOA partitioning increases with increase in volatility and decrease in bulk diffusivity and rate constant. At the same time, the shape of the aerosol size distribution displays appreciable narrowing with decrease in volatility and bulk diffusivity and increase in rate constant. A proper representation of these physicochemical processes and parameters is needed in the next generation models to reliably predict not only the total SOA mass, but also its composition- and number-diameter distributions, all of which together determine the overall optical and cloud-nucleating properties