2,595 research outputs found
On the measurement and impact of fiscal decentralization
The typical post-Bretton Woods era development approach that emphasized central government-led development efforts has changed dramatically, and local governments have clearly emerged as players in development policy. The thinking about what is important to achieve in development objectives is changing as fiscal decentralization reforms are being pursued by many countries around the world. In this context, a number of studies have attempted to quantify the impact of decentralization by relating some measure of it to economic outcomes of fiscal stability, economic growth, and public sector size. But decentralization is surprisingly difficult to measure. Nearly all cases examining the relationship between decentralization and macroeconomic performance have relied on the Government Finance Statistics (GFS) of the International Monetary Fund. However, despite its merits, GFS falls short in providing a full picture of fiscal decentralization. For some countries, however, there is data that more accurately captures fiscal responsibilities among different types of governments.Decentralization,Banks&Banking Reform,Municipal Financial Management,Public&Municipal Finance,Public Sector Economics&Finance,National Governance,Public Sector Economics&Finance,Banks&Banking Reform,Municipal Financial Management,Urban Economics
Kinetic energy budgets in areas of intense convection
A kinetic energy budget analysis of the AVE-SESAME 1 period which coincided with the deadly Red River Valley tornado outbreak is presented. Horizontal flux convergence was found to be the major kinetic energy source to the region, while cross contour destruction was the major sink. Kinetic energy transformations were dominated by processes related to strong jet intrusion into the severe storm area. A kinetic energy budget of the AVE 6 period also is presented. The effects of inherent rawinsonde data errors on widely used basic kinematic parameters, including velocity divergence, vorticity advection, and kinematic vertical motion are described. In addition, an error analysis was performed in terms of the kinetic energy budget equation. Results obtained from downward integration of the continuity equation to obtain kinematic values of vertical motion are described. This alternate procedure shows promising results in severe storm situations
Asymptotic methods for peristaltic transport of a heat-conducting fluid
AbstractTwo asymptotic methods based upon Stokes and long-wave approximations are developed for the study of transporting a heat-conducting fluid through a flexible tube by peristaltic motion of the tube well. The asymptotic methods are justified rigorously and the existence of a unique generalized solution of the governing equations is proved if a condition in terms of the Reynolds number and other nondimensional parameters is satisfied
Bayesian Analysis for Food-Safety Risk Assessment: Evaluation of Dose-Response Functions within WinBUGS
Reply to Comment on "Cosmic rays, carbon dioxide, and climate"
In our analysis [Rahmstorf et al., 2004], we arrived at two main conclusions: the data of Shaviv and Veizer [2003] do not show a significant correlation of cosmic ray flux (CRF) and climate, and the authors' estimate of climate sensitivity to CO2 based on a simple regression analysis is questionable. After careful consideration of Shaviv and Veizer's comment, we want to uphold and reaffirm these conclusions. Concerning the question of correlation, we pointed out that a correlation arose only after several adjustments to the data, including shifting one of the four CRF peaks and stretching the time scale. To calculate statistical significance, we first need to compute the number of independent data points in the CRF and temperature curves being correlated, accounting for their autocorrelation. A standard estimate [Quenouille, 1952] of the number of effective data points is
urn:x-wiley:00963941:media:eost14930:eost14930-math-0001
where N is the total number of data points and r1, r2 are the autocorrelations of the two series. For the curves of Shaviv and Veizer [2003], the result is NEFF = 4.8. This is consistent with the fact that these are smooth curves with four humps, and with the fact that for CRF the position of the four peaks is determined by four spiral arm crossings or four meteorite clusters, respectively; that is, by four independent data points. The number of points that enter the calculation of statistical significance of a linear correlation is (NEFF− 2), since any curves based on only two points show perfect correlation; at least three independent points are needed for a meaningful result
Temperature Fluctuations driven by Magnetorotational Instability in Protoplanetary Disks
The magnetorotational instability (MRI) drives magnetized turbulence in
sufficiently ionized regions of protoplanetary disks, leading to mass
accretion. The dissipation of the potential energy associated with this
accretion determines the thermal structure of accreting regions. Until
recently, the heating from the turbulence has only been treated in an
azimuthally averaged sense, neglecting local fluctuations. However, magnetized
turbulence dissipates its energy intermittently in current sheet structures. We
study this intermittent energy dissipation using high resolution numerical
models including a treatment of radiative thermal diffusion in an optically
thick regime. Our models predict that these turbulent current sheets drive
order unity temperature variations even where the MRI is damped strongly by
Ohmic resistivity. This implies that the current sheet structures where energy
dissipation occurs must be well resolved to correctly capture the flow
structure in numerical models. Higher resolutions are required to resolve
energy dissipation than to resolve the magnetic field strength or accretion
stresses. The temperature variations are large enough to have major
consequences for mineral formation in disks, including melting chondrules,
remelting calcium-aluminum rich inclusions, and annealing silicates; and may
drive hysteresis: current sheets in MRI active regions could be significantly
more conductive than the remainder of the disk.Comment: 16 pages, 13 figures, ApJ In Press, updated to match proof
Xenosurveillance reflects traditional sampling techniques for the identification of human pathogens: A comparative study in West Africa
BACKGROUND: Novel surveillance strategies are needed to detect the rapid and continuous emergence of infectious disease agents. Ideally, new sampling strategies should be simple to implement, technologically uncomplicated, and applicable to areas where emergence events are known to occur. To this end, xenosurveillance is a technique that makes use of blood collected by hematophagous arthropods to monitor and identify vertebrate pathogens. Mosquitoes are largely ubiquitous animals that often exist in sizable populations. As well, many domestic or peridomestic species of mosquitoes will preferentially take blood-meals from humans, making them a unique and largely untapped reservoir to collect human blood.
METHODOLOGY/PRINCIPAL FINDINGS: We sought to take advantage of this phenomenon by systematically collecting blood-fed mosquitoes during a field trail in Northern Liberia to determine whether pathogen sequences from blood engorged mosquitoes accurately mirror those obtained directly from humans. Specifically, blood was collected from humans via finger-stick and by aspirating bloodfed mosquitoes from the inside of houses. Shotgun metagenomic sequencing of RNA and DNA derived from these specimens was performed to detect pathogen sequences. Samples obtained from xenosurveillance and from finger-stick blood collection produced a similar number and quality of reads aligning to two human viruses, GB virus C and hepatitis B virus.
CONCLUSIONS/SIGNIFICANCE: This study represents the first systematic comparison between xenosurveillance and more traditional sampling methodologies, while also demonstrating the viability of xenosurveillance as a tool to sample human blood for circulating pathogens
Chondrule size and related physical properties: a compilation and evaluation of current data across all meteorite groups
The examination of the physical properties of chondrules has generally
received less emphasis than other properties of meteorites such as their
mineralogy, petrology, and chemical and isotopic compositions. Among the
various physical properties of chondrules, chondrule size is especially
important for the classification of chondrites into chemical groups, since each
chemical group possesses a distinct size-frequency distribution of chondrules.
Knowledge of the physical properties of chondrules is also vital for the
development of astrophysical models for chondrule formation, and for
understanding how to utilize asteroidal resources in space exploration. To
examine our current knowledge of chondrule sizes, we have compiled and provide
commentary on available chondrule dimension literature data. We include all
chondrite chemical groups as well as the acapulcoite primitive achondrites,
some of which contain relict chondrules. We also compile and review current
literature data for other astrophysically-relevant physical properties
(chondrule mass and density). Finally, we briefly examine some additional
physical aspects of chondrules such as the frequencies of compound and
'cratered' chondrules. A purpose of this compilation is to provide a useful
resource for meteoriticists and astrophysicists alike.Comment: invited review accepted for publication in Chemie der Erd
Soil-water dynamics and unsaturated storage during snowmelt following wildfire
Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on snowmelt and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the snowmelt period by strong aspect controls on snowmelt and soil thawing. Here we present data from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ∼1–2 °C warmer on average than north-facing burned soils and ∼1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the snowmelt period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during snowmelt, soil-water storage at the end of the snowmelt period reached the value at field capacity for each plot, suggesting that post-snowmelt unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that the amount of snowmelt-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas
Primitive Fine-Grained Matrix in the Unequilbrated Enstatite Chondrites
Enstatite chondrites (EC) have important implications for constraining conditions in the early solar system and for understanding the evolution of the Earth and other inner planets. They are among the most reduced solar system materials as reflected in their mineral compositions and assemblage. They are the only chondrites with oxygen as well as Cr, Ti, Ni and Zn stable isotope compositions similar to the earth and moon and most are completely dry, lacking any evidence of hydrous alteration; the only exception are EC clasts in the Kaidun breccia which have hydrous minerals. Thus, ECs likely formed within the snow line and are good candidates to be building blocks of the inner planets. Our goals are to provide a more detailed characterization the fine-grained matrix in E3 chondrites, understand its origin and relationship to chondrules, decipher the relationship between EH and EL chondrites and compare E3 matrix to matrices in C and O chondrites as well as other fine-grained solar system materials. Is E3 matrix the dust remaining from chondrule formation or a product of parent body processing or both
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