2,039 research outputs found
Determinants of outcomes of Public-Private Partnerships (PPP) in infrastructure in Asia
This study analyzes cross-country data extracted from a large global database to identify the major risks affecting Asian PPP into six major factors: (1) macroeconomic environment; openness of economy; (2) incentive issues during planning, design and contracting phases; (3) political risk; (4) fiscal capacity of government; (5) firm-embodied traits: level of technical efficiency and capacity of proponents in construction and operations; and (6) other reasons - regulation, credit risk of buyers of output, etc. Policy recommendations are made
On the relationship of the scaled phase space and Skyrme-coherent state treatments of proton antiproton annihilation at rest
We discuss pion multiplicities and single pion momentum spectra from proton
antiproton annihilation at rest. Both the scaled phase space model and the
Skyrme-coherent state approach describe these observables well. In the coherent
state approach the puzzling size of the scale parameter relating the phase
space integrals for different multiplicities is replaced by a well defined
weight function. The strength of this function is determined by the intensity
of the classical pion field and its spatial extent is of order 1 fm.Comment: 11 pages including 4 figures(postscript
Circularly Polarized Resonant Rayleigh Scattering and Skyrmions in the = 1 Quantum Hall Ferromagnet
We use the circularly polarized resonant Rayleigh scattering (RRS) to study
the quantum Hall ferromagnet at = 1. At this filling factor we observe a
right handed copolarized RRS which probes the Skyrmion spin texture of the
electrons in the photoexcited grounds state. The resonant scattering is not
present in the left handed copolarization, and this can be related to the
correlation between Skymionic effects, screening and spin wave excitations.
These results evidence that RRS is a valid method for the study of the spin
texture of the quantum Hall states
Plateau insulator transition in graphene
The quantum Hall effect in a single-layer graphene sample is studied in
strong magnetic fields up to 28 T. Our measurements reveal the existence of a
metal- insulator transition from filling factor to . The value
of the universal scaling exponent is found to be in graphene and
therefore in a truly two-dimensional system. This value of is in
agreement with the accepted universal value for the plateau-insulator
transitions in standard quasi two-dimensional electron and hole gases.Comment: 10 pages, 5 figure
The CoRoT B-type binary HD50230: a prototypical hybrid pulsator with g-mode period and p-mode frequency spacings
B-type stars are promising targets for asteroseismic modelling, since their
frequency spectrum is relatively simple.
We deduce and summarise observational constraints for the hybrid pulsator,
HD50230, earlier reported to have deviations from a uniform period spacing of
its gravity modes. The combination of spectra and a high-quality light curve
measured by the CoRoT satellite allow a combined approach to fix the position
of HD50230 in the HR diagram.
To describe the observed pulsations, classical Fourier analysis was combined
with short-time Fourier transformations and frequency spacing analysis
techniques. Visual spectra were used to constrain the projected rotation rate
of the star and the fundamental parameters of the target. In a first
approximation, the combined information was used to interpret multiplets and
spacings to infer the true surface rotation rate and a rough estimate of the
inclination angle.
We identify HD50230 as a spectroscopic binary and characterise the two
components. We detect the simultaneous presence of high-order g modes and
low-order p and g-modes in the CoRoT light curve, but were unable to link them
to line profile variations in the spectroscopic time series. We extract the
relevant information from the frequency spectrum, which can be used for seismic
modelling, and explore possible interpretations of the pressure mode spectrum.Comment: 26 pages, 12+6 figures, accepted for publication in Astronomy and
Astrophysic
Multi-Channel Inverse Scattering Problem on the Line: Thresholds and Bound States
We consider the multi-channel inverse scattering problem in one-dimension in
the presence of thresholds and bound states for a potential of finite support.
Utilizing the Levin representation, we derive the general Marchenko integral
equation for N-coupled channels and show that, unlike to the case of the radial
inverse scattering problem, the information on the bound state energies and
asymptotic normalization constants can be inferred from the reflection
coefficient matrix alone. Thus, given this matrix, the Marchenko inverse
scattering procedure can provide us with a unique multi-channel potential. The
relationship to supersymmetric partner potentials as well as possible
applications are discussed. The integral equation has been implemented
numerically and applied to several schematic examples showing the
characteristic features of multi-channel systems. A possible application of the
formalism to technological problems is briefly discussed.Comment: 19 pages, 5 figure
Separation of azeotropic mixtures using protic ionic liquids as extraction solvents
IF/00190/2014; IF/00210/2014; PTDC/EQU-EQU/29737/2017; PTDC/QEQ-FTT/3289/2014; IF/00210/2014/CP1244/CT0003; UID/QUI/50006/2019; POCI-01-0145-FEDER-007265; University of Pamplona, Internal Project 2-2017.The aim of this work is to evaluate the separation of hydrocarbons (hexane and heptane) from their azeotropic mixtures with ethanol using protic ionic liquid (PIL) as extraction solvents. With this goal in mind, PILs were synthesized and their thermal and physical characterization were carried out. Experimental determination of the phase equilibrium for the ternary systems hydrocarbons + ethanol + PIL at 298.15 K and 101.2 kPa were also carried out in order to evaluate the feasibility of this application. The solute distribution ratio and the selectivity were also determined to compare the solvent capacity of these PILs. The NRTL equation was used to correlate the experimental data. Furthermore, this paper provides a comparison of the solvent capacity of these PILs with different extraction solvents (ionic liquids (ILs), ILs mixtures and deep eutectic solvents) available in the literature. Then, a critical review for the separation of these azeotropic mixtures was carried out using the extraction processes data obtained through the simulation using a conventional software.preprintpublishe
Relación entre calidad y coste de la prescripción farmacológica en atención primaria
ObjetivoAnalizar la prescripcion farmaceutica de los medicos generales (MG) segun un sistema de indicadores cualitativos y evaluar la relacion de estos con el gasto global de prescripcion farmaceutica por habitante.DisenoEstudio descriptivo, retrospectivo.EmplazamientoAtencion primaria.Mediciones y resultados principalesSe evalua la prescripcion farmaceutica de 285 MG de 32 equipos de atencion primaria, siendo la prescripcion individual de cada medico la unidad de analisis. La prescripcion se clasifico en 3 categorias segun su valor intrinseco (%VIF): bajo (. 75%), medio (76–79%) y alto (. 80%). Como trazadores de hiperprescripcion fueron seleccionados: DHD antibioticos (AB), DHD antiinflamatorios no esteroides (AINE) y DHD antiulcerosos (ULC), y como trazadores de seleccion: %DHD cefalosporinas tercera generacion/DHD cefalosporinas totales (CEF3.aG), %DHD quinolonas amplio espectro/DHD quinolonas totales (QAP), %DHD AINE/DHD (AINE + analgesicos) (ANAL). Los indicadores cuantitativos estudiados fueron: gasto total/poblacion asignada (GPA), coste/receta farmacos de eficacia dudosa y coste/DDD de AB, AINE y ULC. Se aplico el analisis de variancia, incluyendo la prueba de Scheffe para comparaciones multiples y la correlacion lineal de Pearson. Un 26% de las prescripciones tenia un %VIF < 75%, mientras que el 34% lo tenia > 80%. Las medias de DHD AB entre las categorias de VIF eran diferentes (p < 0,0001), al igual que las de DHD de AINE (p < 0,0001) y ULC (p = 0,007), observandose un menor consumo de AB, AINE y ULC en las prescripciones con VIF mas alto. Las CEF3aG, asi como ANAL presentan diferencias significativas con las 3 categorias de VIF (p < 0,0001 y p = 0,041) a diferencia del QAP (p = 0,18). El GPA es menor entre los MG cuyas prescripciones tenian el %VIF mas alto; en cambio, el coste/receta y el coste DDD no presentaron diferencias significativas segun categorias de %VIF.ConclusionesLos medicos con mejor perfil cualitativo segun estos indicadores presentan un menor gasto por habitante. En cambio, no se observan diferencias en el coste por receta ni en el coste/tratamiento entre los distintos medicos. Por tanto, las intervenciones deben priorizar la mejora de la calidad de la prescripcion farmaceutica antes que promover unicamente el cambio al farmaco de menor coste.ObjectivesWith a system of qualitative indicators, to analyse the pharmaceutical prescription of general practitioners (GPs), and to evaluate the relationship of these indicators to the overall pharmaceutical prescription expenditure per inhabitant.DesignRetrospective descriptive study.SettingPrimary care.Measurements and main resultsThe drugs prescription of 285 GPs from 32 primary care teams was evaluated, with the individual prescription of each doctor as the unit of analysis. The prescription was classified in 3 categories according to its intrinsic value (IV): low (. 75%), medium (76–79%) and high (. 80%). Selected as tracers of over-prescription were: daily dose per inhabitant (DDI) of antibiotics (AB), DDI of non-steroid anti-inflammatory drugs (NSAID), and DDI of ulcer drugs (ULC). Selected as tracers of selection were: % DDI third-generation cephalosporins/DDI total cephalosporins; % DDI broad-spectre quinolones/DDI total quinolones; and % DDI NSAID/DDI NSAID plus analgesics. Quantitative indicators studied were: total expenditure per allocated population, cost per drugs prescription of doubtful efficacy, and cost per daily dose of AB, NSAID and ULC. Variance analysis, including the Scheffe test for multiple comparisons and Pearson's linear correlation, was applied. 26% of the prescriptions had an IV below 75%, and 34% had an IV above 80%. The means of DDI of AB among the categories of IV were different (p < 0.0001), as were those of DDI of NSAID (p < 0.0001) and of ULC (p = 0.007). Lower consumption of AB, NSAID and ULC was found in prescriptions with the highest IV %. The third-generation cephalosporins and the NSAID + analgesics showed significant differences in the three IV categories (p < 0.0001 and p = 0.041), unlike broad-spectrum quinolones (p = 0.18). The total expenditure per allocated population was less for GPs whose prescriptions had the highest IV %; whereas the cost per prescription and cost per daily dose showed no significant differences for IV categories.ConclusionsThe doctors with the best qualitative profile on these indicators had less expenditure per inhabitant. However, no differences were found in the cost per prescription or cost per treatment between doctors. Therefore, interventions must prioritise improving drug prescription quality rather than just promoting changes to lower-cost drugs
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