206 research outputs found
Assessing, demonstrating and capturing the economic value of marine & coastal ecosystem services in the Bay of Bengal Large Marine Ecosystem
The objective of the study was to assess the economic value of ecosystem services in the Bay of Bengal.The manin aim was to support the development of a Strategic Action Plan (SAP). Findings included: economic consequences of ecosystem change; potential economic instruments to strengthen sustainable management; and recommendations on next steps in using economic valuation
Static pile composting of dairy waste solids for use as animal bedding
A series of thirteen (13) static compost piles were constructed during the period of June, 1985 to March, 1986 at the University of Tennessee Dairy Experiment Station near Lewisburg, Tennessee. The study was performed to investigate the relationship among various compost process parameters (e.g., method of aeration, pile size, and time) and the moisture content and coliform bacteria population in composted dairy waste intended for use as bedding in free stalls.
Both natural and forced aeration methods were employed to supply oxygen to the piles of manure solids. The natural aeration method consisted of nothing more than aging the manure solids in an unconfined pile. The forced aeration method employed a fan to force air into a perforated plenum located underneath the compost pile. The forced aeration system was controlled by either a cycle time switch or a temperature set point controller sensing pile temperature.
Temperatures of the compost mass were monitored daily at three (3) levels within each pile. Samples from three (3) levels were analyzed for moisture content and total coliform bacteria populations on a weekly basis. A heterotrophic plate count - spread plate method was used to enumerate the total coliform bacteria.
Results of the temperature study suggest that the fan had an impact on the composting process such that the piles with the fan reached a higher internal temperature than the piles without the fan. Further, the time to reach maximum temperature was lower for the piles with the fan than for the piles without the fan. However, piles without the fan were able to achieve temperatures generally considered adequate for good composting.
The compost piles of dairy waste solids dried very slowly. There were no differences in drying rates between the two (2) aeration methods or between the two (2) pile sizes.
No consistent trends or patterns were demonstrated by the total conform populations through time with regard to treatment or level within the pile. Observations suggest that in many piles the population first declined but started rebuilding at some later point during the process.
It was anticipated that the total coliform population would decline as the temperature in the pile exceeded their normal living conditions. However, even after several weeks of temperatures above 60°C, total coliform populations of a magnitude similar to those at time zero were found in many samples
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What is the most useful approach for forecasting hydrological extremes during El Niño?
In the past, efforts to prepare for the impacts of El Niño-driven flood and drought hazards have often relied on seasonal precipitation forecasts as a proxy for hydrological extremes, due to a lack of hydrologically relevant information. However, precipitation forecasts are not the best indicator of hydrological extremes. Now, two different global scale hydro-meteorological approaches for predicting river flow extremes are available to support flood and drought preparedness. These approaches are statistical forecasts based on large-scale climate variability and teleconnections, and resource-intensive dynamical forecasts using coupled ocean-atmosphere general circulation models. Both have the potential to provide early warning information, and both are used to prepare for El Niño impacts, but which approach provides the most useful forecasts?
This study uses river flow observations to assess and compare the ability of two recently-developed forecasts to predict high and low river flow during El Niño: statistical historical probabilities of ENSO-driven hydrological extremes, and the dynamical seasonal river flow outlook of the Global Flood Awareness System (GloFAS-Seasonal). Our findings highlight regions of the globe where each forecast is (or is not) skilful compared to a forecast of climatology, and the advantages and disadvantages of each forecasting approach. We conclude that in regions where extreme river flow is predominantly driven by El Niño, or in regions where GloFAS-Seasonal currently lacks skill, the historical probabilities generally provide a more useful forecast. In areas where other teleconnections also impact river flow, with the effect of strengthening, mitigating or even reversing the influence of El Niño, GloFAS-Seasonal forecasts are typically more useful
The classification of irreducible admissible mod p representations of a p-adic GL_n
Let F be a finite extension of Q_p. Using the mod p Satake transform, we
define what it means for an irreducible admissible smooth representation of an
F-split p-adic reductive group over \bar F_p to be supersingular. We then give
the classification of irreducible admissible smooth GL_n(F)-representations
over \bar F_p in terms of supersingular representations. As a consequence we
deduce that supersingular is the same as supercuspidal. These results
generalise the work of Barthel-Livne for n = 2. For general split reductive
groups we obtain similar results under stronger hypotheses.Comment: 55 pages, to appear in Inventiones Mathematica
Three dimensional hysdrodynamic lattice-gas simulations of binary immiscible and ternary amphiphilic flow through porous media
We report the results of a study of multiphase flow in porous media. A
Darcy's law for steady multiphase flow was investigated for both binary and
ternary amphiphilic flow. Linear flux-forcing relationships satisfying Onsager
reciprocity were shown to be a good approximation of the simulation data. The
dependence of the relative permeability coefficients on water saturation was
investigated and showed good qualitative agreement with experimental data.
Non-steady state invasion flows were investigated, with particular interest in
the asymptotic residual oil saturation. The addition of surfactant to the
invasive fluid was shown to significantly reduce the residual oil saturation.Comment: To appear in Phys. Rev.
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Developing a global operational seasonal hydro-meteorological forecasting system: GloFAS-Seasonal v1.0
Global overviews of upcoming flood and drought events are key for many applications, including disaster risk reduction initiatives. Seasonal forecasts are designed to provide early indications of such events weeks, or even months, in advance, but seasonal forecasts for hydrological variables at large or global scales are few and far between. Here, we present the first operational global scale seasonal hydro-meteorological forecasting system: GloFAS-Seasonal. Developed as an extension of the Global Flood Awareness System (GloFAS), GloFAS-Seasonal couples seasonal meteorological forecasts from ECMWF with a hydrological model, to provide openly available probabilistic forecasts of river flow out to 4 months ahead for the global river network. This system has potential benefits not only for disaster risk reduction through early awareness of floods and droughts, but also for water-related sectors such as agriculture and water resources management, in particular for regions where no other forecasting system exists. We describe the key hydro-meteorological components and computational framework of GloFAS-Seasonal, alongside the forecast products available, before discussing initial evaluation results and next steps
From local watershed management to integrated river basin management at national and transboundary levels
Watersheds face a range of degradation challenges associated with human activities, such as pollution, deforestation and changes in sediment generation. The way they are managed has a profound cascading effect on natural resources and communities in the wider basin. Although watersheds play a critical role as the basic hydrological unit within a river basin they are often neglected in river basin management.
Over the past decade, principles and practices have evolved to ensure that integrated water resources management (IWRM) approaches used at the broader basin level to address sustainable development and management of land and water resources also apply at the smaller watershed level.
This technical report is a synthesis of the knowledge, lessons learned and good practices presented and discussed at the International Conference on Watershed Management held in Chiang Mai, Thailand 9-11 March 2011
Lattice Boltzmann simulations of lamellar and droplet phases
Lattice Boltzmann simulations are used to investigate spinodal decomposition
in a two-dimensional binary fluid with equilibrium lamellar and droplet phases.
We emphasise the importance of hydrodynamic flow to the phase separation
kinetics. For mixtures slightly asymmetric in composition the fluid phase
separates into bulk and lamellar phases with the lamellae forming distinctive
spiral structures to minimise their elastic energy.Comment: 19 pages, 5 figure
Modular symbols in Iwasawa theory
This survey paper is focused on a connection between the geometry of
and the arithmetic of over global fields,
for integers . For over , there is an explicit
conjecture of the third author relating the geometry of modular curves and the
arithmetic of cyclotomic fields, and it is proven in many instances by the work
of the first two authors. The paper is divided into three parts: in the first,
we explain the conjecture of the third author and the main result of the first
two authors on it. In the second, we explain an analogous conjecture and result
for over . In the third, we pose questions for general
over the rationals, imaginary quadratic fields, and global function fields.Comment: 43 page
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Continental and global scale flood forecasting systems
Floods are the most frequent of natural disasters, affecting millions of people across the globe every year. The anticipation and forecasting of floods at the global scale is crucial to preparing for severe events and providing early awareness where local flood models and warning services may not exist. As numerical weather prediction models continue to improve, operational centres are increasingly using the meteorological output from these to drive hydrological models, creating hydrometeorological systems capable of forecasting river flow and flood events at much longer lead times than has previously been possible. Furthermore, developments in, for example, modelling capabilities, data and resources in recent years have made it possible to produce global scale flood forecasting systems. In this paper, the current state of operational large scale flood forecasting is discussed, including probabilistic forecasting of floods using ensemble prediction systems. Six state-of-the-art operational large scale flood forecasting systems are reviewed, describing similarities and differences in their approaches to forecasting floods at the global and continental scale. Currently, operational systems have the capability to produce coarse-scale discharge forecasts in the medium-range and disseminate forecasts and, in some cases, early warning products, in real time across the globe, in support of national forecasting capabilities. With improvements in seasonal weather forecasting, future advances may include more seamless hydrological forecasting at the global scale, alongside a move towards multi-model forecasts and grand ensemble techniques, responding to the requirement of developing multi-hazard early warning systems for disaster risk reduction
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