Unpleasant surprises : sovereign default determinants and prospects

This paper uses model averaging techniques to identify robust predictors of sovereign default episodes on a pooled database for 46 emerging economies over the period 1980-2004. Sovereign default episodes are defined according to Standard&Poor’s or by non-concessional International Monetary Fund loans in excess of 100 percent of the country’s quota. The authors find that, in addition to the level of indebtedness, the quality of policies and institutions is the best predictor of default episodes in emerging market countries with relatively low levels of external debt. For emerging market countries with a higher level of debt, macroeconomic stability plays a robust role in explaining differences in default probabilities. The paper provides evidence that model averaging can improve out-of-sample prediction of sovereign defaults, and draws policy conclusions for the current crisis based on the results.Debt Markets,External Debt,Bankruptcy and Resolution of Financial Distress,Economic Theory&Research,Currencies and Exchange Rates

Influence of incoherent scattering on stochastic deflection of high-energy negative particle beams in bent crystals

An investigation on stochastic deflection of high-energy negatively charged particles in a bent crystal was carried out. On the basis of analytical calculation and numerical simulation it was shown that it exists a maximum angle at which most of the beam is deflected. The existence of a maximum, which is taken in the correspondence of the optimal radius of curvature, is a novelty with respect to the case of positively charged particles, for which the deflection angle can be freely increased by increasing the crystal length. This difference has to be ascribed to the stronger contribution of incoherent scattering affecting the dynamics of negative particles that move closer to atomic nuclei and electrons. We therefore identified the ideal parameters for the exploitation of axial confinement for negatively charged particle beam manipulation in future high-energy accelerators, e.g., ILC or muon colliders

Planar channeling and quasichanneling oscillations in a bent crystal

Particles passing through a crystal under planar channeling experience transverse oscillations in their motion. As channeled particles approach the atomic planes of a crystal, they are likely to be dechanneled. This effect was used in ion-beam analysis with MeV energy. We studied this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We found the conditions for the appearance or not of channeling oscillations. Indeed a new kind of oscillations, strictly related to the motion of over-barrier particles, i.e. quasichanneling particles, has been predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we studied this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal has been found and optimized.Comment: 25 pages, 11 figure

Sobrecarga de pacientes en el servicio de urgencias y emergencias

Para lograr un servicio de urgencias verdaderamente eficiente son necesarias, entre otras variables, la rapidez y la calidad en la prestación del servicio. Estas variables se ven afectadas cuando hay una sobre carga de servicio, la cual consiste es un aumento notable en la cantidad de pacientes que asisten al servicio de guardia de urgencias para ser atendidos. Se observa a su vez, que las diversas afecciones por las que asisten los pacientes no entran en los parámetros de urgencias ni emergencias. Ante esta problemática se ve afectada la salud del personal de salud (médicos y enfermeros), los cuales manifiestan agotamiento físico y mental ante tal aumento de trabajo. Una de las tareas para evitar esta situación será educar a las personas con respecto a las patologías, así ellos lograran identificar cuáles son consideradas urgencias y cuáles deben ser atendidas en servicio de consultorio externo. El presente trabajo de investigación tiene como objetivo general determinar cuáles son los factores socioeconómicos y culturales que inciden en la sobrecarga de pacientes del servicio de emergencia del Centro de Salud nº101 José María Méndez, de la cuidad de La Consulta, en el departamento de San Carlos, Mendoza, en el año 2012. Objetivos específicos: medir y cuantificar la asistencia de los pacientes a dicho servicio; identificar sobrecarga en el servicio de urgencia; identificar factores geográficos, económicos y culturales que generan un incremento de consultas en el servicio de emergencias sin ser las mismas, verdaderas emergencias médicas; comprender modos de comportamiento y costumbres de los pacientes en el sistema de salud; identificar conocimientos de la población sobre problemas médicos de urgencias.Fil: Bandiera B., Graciana L.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..Fil: Garín, Belén A.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería.

HELP-based matrices for stimuli-responsive controlled release of bioactive compounds

Direct delivery of bioactive substances to the sites of injury represents a key issue for therapies based on regenerative medicine and tissue repair [1]. Protein derived hydrogels represent an interesting system for this purpose because they possess several features that make them suitable to this purpose. A method for preparation of hydrogel matrices based on Human Elastin-like Polypeptide (HELP) has been set up [2]. HELPs are a family of elastin-like recombinant biopolymers modeled after the most regularly repeated domain in human tropoelastin, retaining peculiar properties as self-assembling and thermoresponsive behavior [3]. In this study we assayed two elastolytic activities from different sources to test their potential to specifically degrade the HELP matrix

Unpleasant Surprises: Sovereign Default Determinants and Prospects, Policy Research Working Papers, 5401

This paper uses model averaging techniques to identify robust predictors of sovereign default episodes on a pooled database for 46 emerging economies over the period 1980-2004. Sovereign default episodes are defined according to Standard & Poor s or by non-concessional International Monetary Fund loans in excess of 100 percent of the country s quota. The authors find that, in addition to the level of indebtedness, the quality of policies and institutions is the best predictor of default episodes in emerging market countries with relatively low levels of external debt. For emerging market countries with a higher level of debt, macroeconomic stability plays a robust role in explaining differences in default probabilities. The paper provides evidence that model averaging can improve out-of-sample prediction of sovereign defaults, and draws policy conclusions for the current crisis based on the results

A novel ultrafast-low-dose computed tomography protocol allows concomitant coronary artery evaluation and lung cancer screening

BACKGROUND:Cardiac computed tomography (CT) is often performed in patients who are at high risk for lung cancer in whom screening is currently recommended. We tested diagnostic ability and radiation exposure of a novel ultra-low-dose CT protocol that allows concomitant coronary artery evaluation and lung screening. METHODS: We studied 30 current or former heavy smoker subjects with suspected or known coronary artery disease who underwent CT assessment of both coronary arteries and thoracic area (Revolution CT, General Electric). A new ultrafast-low-dose single protocol was used for ECG-gated helical acquisition of the heart and the whole chest. A single IV iodine bolus (70-90 ml) was used. All patients with CT evidence of coronary stenosis underwent also invasive coronary angiography. RESULTS: All the coronary segments were assessable in 28/30 (93%) patients. Only 8 coronary segments were not assessable in 2 patients due to motion artefacts (assessability: 98%; 477/485 segments). In the assessable segments, 20/21 significant stenoses (> 70% reduction of vessel diameter) were correctly diagnosed. Pulmonary nodules were detected in 5 patients, thus requiring to schedule follow-up surveillance CT thorax. Effective dose was 1.3 ± 0.9 mSv (range: 0.8-3.2 mSv). Noteworthy, no contrast or radiation dose increment was required with the new protocol as compared to conventional coronary CT protocol. CONCLUSIONS:The novel ultrafast-low-dose CT protocol allows lung cancer screening at time of coronary artery evaluation. The new approach might enhance the cost-effectiveness of coronary CT in heavy smokers with suspected or known coronary artery disease

simulation code for modeling of coherent effects of radiation generation in oriented crystals

We present the crystalrad simulation code, combining all the features of the crystal simulation code for simulations of charged particles trajectories in a bent crystal and the radcharm++ code for calculation of the radiation spectrum. The crystalrad code is based on Monte Carlo simulations of trajectories in the planar and axial electric field either in a straight, bent, or periodically bent crystal taking into account multiple and single Coulomb scattering on nuclei and electrons, nuclear scattering and ionization energy losses. The trajectories simulated are used for calculation of radiation spectra by the Baier-Katkov method. We compare our simulations with experimental data taken at MAMI (MAinzer MIkrotron) as well as give an example for a possible future study with sub-GeV electrons interacting with Si bent crystals

Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected sensitivities for the proposed experiment using a layout based on the LHCb detector.Comment: 19 pages, 13 figure