357 research outputs found
Participatory Irrigation Management : comparing theory with practice a case study of the Beni Amir irrigation scheme in Morocco
International audienceParticipatory Irrigation Management (PIM) and Irrigation Management Transfer (IMT) are studied at three levels : the international literature, the policy and action taken in Morocco and field work in the Beni Amir large scale irrigation system. International literature argues that management will improve if users can take management decisions that are the outcome of local negotiations between stakeholders and based on local knowledge and normative frameworks. Since the 1980s, several governments have adopted these turnover programs, often as part of the requirements of a structural adjustment package negotiated with IMF and international development banks. This shows that in many countries the tight financial situation of governments has been important for introducing PIM/IMT. The management transfer from the State to Water Users Associations (WUAs) has been more successfully achieved in some places (Mexico, Colombia and Turkey), than in other places (India, Pakistan, Philippines). Literature provides explanations as success factors for PIM/IMT like relative strength of economy and central government, higher literacy and standard of living. These factors are largely valid for Morocco and thus raises the question about the Moroccan progress in the domain of PIM in large scale irrigation. PIM policy was introduced by the government in 1990 and specified in 1995 as a policy that should be progressively spread, selective depending on location, adapted to the physical and organizational environment, contractual with the water users as partner and finally provide financial advantages for the water users. Field research took place in the Beni Amir large-scale irrigation system in Morocco, situated 200 km south east of Casablanca, where PIM policy became an issue in 1990. In the context of disengagement of the Moroccan state, objectives of the regional government agency responsible for irrigation management in the area (named ORMVAT, Office régional de mise en valeur agricole du Tadla) are to evolve from a complete State management up to farm level, to a more participatory management.Recent field work in which a check list of management tasks performed by farmers was used, showed that, contrary to the policy objectives, WUAs in the Beni Amir system are weakly involved in decision making and hardly perform tasks in irrigation system management. We found that PIM implementation in Morocco does not comply with the theoretical models that have been developed in Mexico, Turkey, the Philippines or elsewhere. This proves the hypothesis that PIM is context-specific which requires that before attempting to implement major institutional reforms in the irrigation sector, it is necessary to understand the national as well as the local context, the opportunities it offers, and the constraints it places on successful institutional reform. Even though local conditions in Beni Amir somehow fit with some points of the theory related to PIM/IMT (i.e. water scarcity should stimulate irrigation reform, the relatively good performance of the infrastructure should permit that IMT programs take off relatively “quickly”, availability of cash money for farmers to pay water fees), PIM programs did not come off the ground in Beni Amir. Case specific reasons that could explain the hesitance of PIM/IMT implementation are i) the irrigated perimeter of Beni Amir, as it is managed nowadays by the ORMVAT, functions relatively well, ii) the society is characterised by relatively strong central rule, iii) rigid labour relations in the civil service and iv) farmers are hesitant to take over the irrigation management
Inferring metabolic mechanisms of interaction within a defined gut microbiota
The diversity and number of species present within microbial communities create the potential for a multitude of interspecies metabolic interactions. Here, we develop, apply, and experimentally test a framework for inferring metabolic mechanisms associated with interspecies interactions. We perform pairwise growth and metabolome profiling of co-cultures of strains from a model mouse microbiota. We then apply our framework to dissect emergent metabolic behaviors that occur in co-culture. Based on one of the inferences from this framework, we identify and interrogate an amino acid cross-feeding interaction and validate that the proposed interaction leads to a growth benefit in vitro. Our results reveal the type and extent of emergent metabolic behavior in microbial communities composed of gut microbes. We focus on growth-modulating interactions, but the framework can be applied to interspecies interactions that modulate any phenotype of interest within microbial communities
Manufacture of desired end products by means of fine treatment of coal tar resin
The possibility of desired end product manufacture from by-product coke industry wastes is shown. A large number of valuable products can be obtained from different fractions of coal tar resin by their fine treatment. The products obtained in this way find application in medical and chemical industries and etc. Moreover, recycling of by-product coke wastes into end products solves the problem of their utilization
High-boiling components in straw oil
Investigation of straw oil and polymer quality produced in the process of its regeneration has been carried out. The conclusions about using polymers as a material for base end products are made. Flow scheme of technological treatment of straw oil wastes is suggested
Technique of complex slime water treatment of coal-mining branch
The possibility of complex slime water treatment at coal-mining and coal-treating plants producing marketable products: power-generating concentrate, coal-water fuel, magnetic fraction, industrial water is shown. A basic process flowsheet of slime water treatment presenting a united technological complex is suggested
The NASA Exoplanet Archive: Data and Tools for Exoplanet Research
We describe the contents and functionality of the NASA Exoplanet Archive, a
database and tool set funded by NASA to support astronomers in the exoplanet
community. The current content of the database includes interactive tables
containing properties of all published exoplanets, Kepler planet candidates,
threshold-crossing events, data validation reports and target stellar
parameters, light curves from the Kepler and CoRoT missions and from several
ground-based surveys, and spectra and radial velocity measurements from the
literature. Tools provided to work with these data include a transit ephemeris
predictor, both for single planets and for observing locations, light curve
viewing and normalization utilities, and a periodogram and phased light curve
service. The archive can be accessed at
http://exoplanetarchive.ipac.caltech.edu.Comment: Accepted for publication in the Publications of the Astronomical
Society of the Pacific, 4 figure
Metabolic design of macroscopic bioreaction models: application to Chinese hamster ovary cells
The aim of this paper is to present a systematic methodology to design macroscopic bioreaction models for cell cultures based upon metabolic networks. The cell culture is seen as a succession of phases. During each phase, a metabolic network represents the set of reactions occurring in the cell. Then, through the use of the elementary flux modes, these metabolic networks are used to derive macroscopic bioreactions linking the extracellular substrates and products. On this basis, as many separate models are obtained as there are phases. Then, a complete model is obtained by smoothly switching from model to model. This is illustrated with batch cultures of Chinese hamster ovary cells
Anisotropic effect of Cd and Hg doping on Pauli limited superconductor CeCoIn
We investigated the effect of Cd and Hg doping on the first order
superconducting (SC) transition and the high field-low temperature SC state of
CeCoIn by measuring the specific heat of CeCo(InCd) with x=0.0011, 0.0022 and 0.0033 and CeCo(InHg) with x=0.00016, 0.00032, and 0.00048 at temperatures down to 0.1 K and
fields up to 14 T. Cd substitution rapidly suppresses the cross-over
temperature , where the superconducting transition changes from
second to first order, to =0 K with x=0.0022 for [100], while
it remains roughly constant up to x=0.0033 for [001]. The
associated anomaly of the proposed FFLO state in Hg-doped samples is washed out
by x=0.00048, while remaining at the same temperature, indicating high
sensitivity of that state to impurities. We interpret these results as
supporting the non-magnetic, possibly FFLO, origin of the high field - low
temperature state in CeCoIn
In Vivo Gene Essentiality and Metabolism in Bordetella pertussis
Bordetella pertussis is the causative agent of whooping cough, a serious respiratory illness affecting children and adults, associated with prolonged cough and potential mortality. Whooping cough has reemerged in recent years, emphasizing a need for increased knowledge of basic mechanisms of B. pertussis growth and pathogenicity. While previous studies have provided insight into in vitro gene essentiality of this organism, very little is known about in vivo gene essentiality, a critical gap in knowledge, since B. pertussis has no previously identified environmental reservoir and is isolated from human respiratory tract samples. We hypothesize that the metabolic capabilities of B. pertussis are especially tailored to the respiratory tract and that many of the genes involved in B. pertussis metabolism would be required to establish infection in vivo. In this study, we generated a diverse library of transposon mutants and then used it to probe gene essentiality in vivo in a murine model of infection. Using the CON-ARTIST pipeline, 117 genes were identified as conditionally essential at 1 day postinfection, and 169 genes were identified as conditionally essential at 3 days postinfection. Most of the identified genes were associated with metabolism, and we utilized two existing genome-scale metabolic network reconstructions to probe the effects of individual essential genes on biomass synthesis. This analysis suggested a critical role for glucose metabolism and lipooligosaccharide biosynthesis in vivo. This is the first genome-wide evaluation of in vivo gene essentiality in B. pertussis and provides tools for future exploration. IMPORTANCE Our study describes the first in vivo transposon sequencing (Tn-seq) analysis of B. pertussis and identifies genes predicted to be essential for in vivo growth in a murine model of intranasal infection, generating key resources for future investigations into B. pertussis pathogenesis and vaccine design
Signatures of arithmetic simplicity in metabolic network architecture
Metabolic networks perform some of the most fundamental functions in living
cells, including energy transduction and building block biosynthesis. While
these are the best characterized networks in living systems, understanding
their evolutionary history and complex wiring constitutes one of the most
fascinating open questions in biology, intimately related to the enigma of
life's origin itself. Is the evolution of metabolism subject to general
principles, beyond the unpredictable accumulation of multiple historical
accidents? Here we search for such principles by applying to an artificial
chemical universe some of the methodologies developed for the study of genome
scale models of cellular metabolism. In particular, we use metabolic flux
constraint-based models to exhaustively search for artificial chemistry
pathways that can optimally perform an array of elementary metabolic functions.
Despite the simplicity of the model employed, we find that the ensuing pathways
display a surprisingly rich set of properties, including the existence of
autocatalytic cycles and hierarchical modules, the appearance of universally
preferable metabolites and reactions, and a logarithmic trend of pathway length
as a function of input/output molecule size. Some of these properties can be
derived analytically, borrowing methods previously used in cryptography. In
addition, by mapping biochemical networks onto a simplified carbon atom
reaction backbone, we find that several of the properties predicted by the
artificial chemistry model hold for real metabolic networks. These findings
suggest that optimality principles and arithmetic simplicity might lie beneath
some aspects of biochemical complexity
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