10,909 research outputs found
Regional integration as diplomacy
Regional integration agreements (RIAs) are examples of second best and have an ambiguous impact on welfare, contend the authors. They build a model in which RIAs unambiguously raise welfare by correcting for externalities. It assumes that trade between neighboring countries increases trust between them and reduces the likelihood of conflict. The optimum intervention in that case is a subsidy on imports from the neighbor. The authors show that an equivalent solution is for the neighboring countries to tax imports fromthe rest of the world -that is, to form an RIA- together with imposing some domestic taxes. In fact, security threats have moved neighboring countries to form RIAs. Examples include the creation of the European Coal and Steel Community (1951) and the European Economic Community (1957) to reduce the threat of war in Europe, as well as various RIAs among developing countries. The authors show, among other things, that: 1) the optimum tariffs on imports from the rest of the world are likely to decline over time; 2) deep integration implies lower optimum external tariffs if it is exogenous; 3) but if deep integration is endogenous, it implies higher optimum external tariffs before it occurs and lower ones thereafter; and 4) enlargement of a bloc (in terms of symmetric countries) has an ambiguous impact on external tariffs but improves welfare, and some form of domino effect exists in the sense that enlargement increases the incentive for nonmembers to seek accession. Although externalities associated with security matters imply that an RIA may maximize welfare, this model suggests that the RIA is a transitory arrangement in the sense that optimum trade preferences are highest at the time the RIA is formed (when security is low) and tend to decline over time. In other words, the RIA's external trade policy becomes increasingly open over time (as well as following deep integration).Rules of Origin,Environmental Economics&Policies,Economic Theory&Research,Payment Systems&Infrastructure,Trade Policy,Trade Policy,Environmental Economics&Policies,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade and Regional Integration
Hospital Quality Oversight by the Joint Commission on the Accreditation of Healthcare Organizations
Regional cooperation, and the role of international organizations and regional integration
The authors examine regional cooperation among neighboring countries in the area of regional public goods. These public goods include water basins (such as lakes, rivers, and underground water), infrastructure (such as roads, railways, and dams), energy, and the environment. Their analysis focuses on developing countries and the potentially beneficial role that international organizations and regional integration may play in bringing the relevant countries to a cooperative equilibrium. A major problem in reaching a cooperative solution is likely tobe the lack of trust. If neighboring countries do not trust each other because of past problems, they may fail to reach a cooperative solution as each tries to maximize its gain from the regional public good. These strategies typically do not account for spillover effects and ultimately leads to losses for all parties. Other constraints on reaching a cooperative solution are its complexity and the financial requirements. Two types of institutions may help resolve some or all of these problems. International organizations can help with trust, expertise, and financing. The United Nations and the World Bank have been involved in a number of such projects in Africa, Asia, and elsewhere, and have been successful in helping parties reach cooperative solutions. Regional integration agreements, though not necessary for regional cooperation, may also be helpful by embedding the negotiations on regional cooperation in a broader institutional framework. The authors examine these issues with the support of both analysis and a number of case studies.Environmental Economics&Policies,Water and Industry,Decentralization,Water Conservation,Common Property Resource Development,Water Supply and Sanitation Governance and Institutions,Water and Industry,Water Conservation,Environmental Economics&Policies,Common Property Resource Development
Computational analysis of hypersonic flows past elliptic-cone waveriders
A comprehensive study for the inviscid numerical calculation of the hypersonic flow past a class of elliptic-cone derived waveriders is presented. The theoretical background associated with hypersonic small-disturbance theory (HSDT) is reviewed. Several approximation formulas for the waverider compression surface are established. A CFD algorithm is used to calculate flow fields for the on-design case and a variety of off-design cases. The results are compared with HSDT, experiment, and other available CFD results. For the waverider shape used in previous investigations, the bow shock for the on-design condition stands off from the leading-edge tip of the waverider. It was found that this occurs because the tip was too thick according to the approximating shape formula that was used to describe the compression surface. When this was corrected, the bow shock became closer to attached as it should be. At Mach numbers greater than the design condition, a lambda-shock configuration develops near the tip of the compression surface. At negative angles of attack, other complicated shock patterns occur near the leading-edge tip. These heretofore unknown flow patterns show the power and utility of CFD for investigating novel hypersonic configurations such as waveriders
Relating in situ hydraulic conductivity, particle size and relative density of superficial deposits in a heterogeneous catchment
Estimating the permeability of superficial deposits is fundamental to many aspects of catchment science, but can be problematic where insufficient in situ measurements are available from pumping tests in piezometers. Consequently, common practice is to estimate permeability from the material description or, where available, particlesize distribution using a formula such as Hazen. In this study, we examine the relationships between particlesize, relativedensity and hydraulicconductivity in superficial deposits in Morayshire, Northern Scotland: a heterogeneous environment typical of many catchments subject to previous glaciations. The superficial deposits comprise glaciofluvial sands and gravels, glacial tills and moraines, raised marine sediments, and blown sands. Thirty-eight sites were investigated: hydraulicconductivity measurements were made using repeated Guelph permeameter measurements, cone resistance was measured in situ with a Panda dynamic cone penetrometer; material descriptions were made in accordance with BS5930:1999; and disturbed samples were taken for particlesize analysis. Overall hydraulicconductivity (K) varied from 0.001 m/d to >40 m/d; glacial till had the lowest K (median 0.027 m/d) and glacial moraine the highest K (median 30 m/d). However, within each geological unit there was great variability in measured hydraulicconductivity values. Multiple linear regression of the data indicated that log d10 and relativedensity (indicated by cone resistance or BS5930:1999 soil state description) were independent predictors of log K and together gave a relationship with an R2 of 0.80. Material description using the largest fraction (e.g. sand or gravel) had little predictive power. Therefore, in heterogeneous catchments, the permeability of superficial deposits is most strongly related to the finest fraction (d10) and relativedensity of the material. In situ Guelph permeameter measurements at outcrops with good geological characterisation provide an easy and reliable method of determining the permeability of particular units of superficial deposits
Investigations of rapid groundwater flow and karst in the Chalk
This study, with fieldwork undertaken in the Pang and Lambourn catchments in
Southern England, investigates the occurrence and distribution of rapid groundwater
flow in the Chalk and evaluates the degree of karstification.
A survey of surface karst features revealed a clear spatial pattern in their distribution
with three distinctive geomorphological zones. Stream sinks and dolines occur
frequently in Zone 1 where there is extensive Palaeogene cover. Only dolines are
present in Zone 2 where Clay-with-Flints deposits overlie areas of the Chalk and there
is little surface karst, other than dry valleys, in Zone 3 where the Chalk outcrops.
Tracer tests from three stream sinks in Zone 1 demonstrated connections to springs and
rapid groundwater flow (1-6 km.d-1) indicating connected networks of conduits and
large fissures over distances up to 5.1 km. Rapid flow was accompanied by variable
tracer attenuation. Unsuccessful results at two other stream sinks were probably due to
total attenuation. Further investigation at one site using four dyes and one
bacteriophage tracer demonstrated the occurrence of diffusion (probably into the Chalk
matrix), but indicated that diffusion is only a minor contributor to attenuation. Very
high tracer losses (~75 % of dye and ~ 99% of bacteriophage) appear to be due to
transport down multiple flowpaths, many comprising at least one section in which flow
is through narrow fissures and fractures.
The Single Borehole Dilution technique was developed to identify the distribution of
flowing horizons in all three zones. Flow horizons decrease with depth below ground
level but have an average spacing of ~ 9 m. Comparison with borehole imaging data
suggested that solutional enlargement of fractures to form fissures, tubules and small
conduits is common in all areas, but that these features may have limited lateral extent.
Overall the Chalk appears to be mildly karstic with small-scale karst development
resembling the early stages of speleogenesis
A gauge theory of quantum mechanics
An Abelian gerbe is constructed over classical phase space. The 2-cocycles
defining the gerbe are given by Feynman path integrals whose integrands contain
the exponential of the Poincare-Cartan form. The U(1) gauge group on the gerbe
has a natural interpretation as the invariance group of the Schroedinger
equation on phase space.Comment:
Inactivation of Mandelate Racemase by 3-Hydroxypyruvate Reveals a Potential Mechanistic Link between Enzyme Superfamilies
Mandelate racemase (MR), a member of the enolase superfamily, catalyzes the Mg2+-dependent interconversion of the enantiomers of mandelate. Several α-keto acids are modest competitive inhibitors of MR [e.g., mesoxalate (Ki = 1.8 ± 0.3 mM) and 3-fluoropyruvate (Ki = 1.3 ± 0.1 mM)], but, surprisingly, 3-hydroxypyruvate (3-HP) is an irreversible, time-dependent inhibitor (kinact/KI = 83 ± 8 M–1 s–1). Protection from inactivation by the competitive inhibitor benzohydroxamate, trypsinolysis and electrospray ionization tandem mass spectrometry analyses, and X-ray crystallographic studies reveal that 3-HP undergoes Schiff-base formation with Lys 166 at the active site, followed by formation of an aldehyde/enol(ate) adduct. Such a reaction is unprecedented in the enolase superfamily and may be a relic of an activity possessed by a promiscuous progenitor enzyme. The ability of MR to form and deprotonate a Schiff-base intermediate furnishes a previously unrecognized mechanistic link to other α/β-barrel enzymes utilizing Schiff-base chemistry and is in accord with the sequence- and structure-based hypothesis that members of the metal-dependent enolase superfamily and the Schiff-base-forming N-acetylneuraminate lyase superfamily and aldolases share a common ancestor
Annotated bibliography on hypoxia and its effects on marine life, with emphasis on the Gulf of Mexico
This bibliography contains 73 annotated references from publications and reports concerning hypoxia, .,;
2.0 ppm dissolved oxygen concentration, in the Gulf of Mexico. Instances of hypoxia from similar habitats and
the effects of low oxygen levels on marine or estuarine organisms are also included. (PDF file contains 15 pages.
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