31 research outputs found
Bistability in Kerr lens mode-locked Ti:sapphire lasers
No full textFemtosecond pulse Ti:sapphire lasers can operate in different ways for the same values of the control parameters. This phenomenon of multistability is explained in a simple way by a theoretical approach using iterative or Poincaré maps. We present experimental confirmation of the predictions of the approach regarding the slope (of pulse duration vs. group velocity dispersion) and regions of stability of two different regimes of mode locking, i.e. transform-limited and chirped output pulses.Fil: Kovalsky, Marcelo Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Hnilo, Alejandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Libertun, Ariel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Electrónica Cuántica; ArgentinaFil: Marconi, Mario Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Electrónica Cuántica; Argentin
Hagiografía, milagros y providencia: fundamentos teológico-históricos de la Historia Francorum de Gregorio de Tours (siglo VI)
No full textResumen: San Gregorio de Tours es un autor galorromano que vivió una época de confusión y turbulencias a causa de las invasiones bárbaras y las herejías. Con una formación centrada fundamentalmente en las Sagradas Escrituras, él se propuso mostrar la historia de su tiempo y la intervención de Dios en ella a través de los milagros. Su principal obra, la Historia de los francos (Historia Francorum), se enmarca dentro de la dinámica cristiana de la «teología de la historia». Aunque en ella se evidencia una visión más bien local, también se encuentra presente un sentido universal cristiano. Su relato se constituye en un texto de capital importancia para comprender el cambio desde la concepción imperial romana hacia nuevas realidades históricas particulares, en este caso, el mundo de los francos. Con un fi n pastoral y moralizador, este obispo de Tours aborda la acción de la Providencia en la historia –especialmente a través de la hagiografía–, así como el problema de la necesaria conversión de los individuos y de los pueblos.
Palabras Clave: Teología de la historia, Providencia, milagros, Gregorio de Tours, conversión.
Abstract: The Gallo-Roman author Saint Gregory of Tours lived in a period of chaos and turbulences caused by the Barbarian invasions and the current heresies. With a formation mainly centered in the Scriptures, his proposal was to prove God’s intervention in the history of his time through His miracles. His main work, the Historia Francorum is framed inside the Christian dynamics of the ‘theology of history’. Although it evidences a more less local vision, it is also present a Christian universal sense. His narration has become a text of capital importance for the best understanding of the change from the Roman imperial vision to new historical realities; in this particular case, the world of Francs. This Bishop of Tours studies Providence action through history –especially through hagiography– with an objective both pastoral and moralizer, and, with a similar goal, the problem of the necessary conversion of individuals and societies.
Keywords: Theology of history, Providence, miracles, Gregory of Tours, conversio
Contractual savings institutions and banks'stability and efficiency
No full textThe authors analyze the relationship between the development of contractual savings institutions and banks'efficiency, credit, and liquidity risks. They discuss the potential mechanisms through which the development of contractual savings institutions may affect the banking sector. They show that the development of contractual savings institutions has a significant impact on bank spreads and loan maturity. After controlling for banks'characteristics, macroeconomic factors, and more standard indicators of financial development, they show that the development of contractual savings institutions is associated with increased efficiency of the banking system and greater resilience to credit and liquidity risks.Payment Systems&Infrastructure,Banks&Banking Reform,Economic Theory&Research,Financial Intermediation,Insurance&Risk Mitigation,Contractual Savings,Banks&Banking Reform,Financial Intermediation,Economic Theory&Research,Insurance&Risk Mitigation
Transforming the old into a foundation for the new - lessons of the Moldova ARIA Project
No full textThis paper is a case study of what is recognized as one of the more successful projects in any country in the Europe and Central Asia region, not to mention in the poorest country of the region-Moldova. The ARIA project shows new ways to attack some of the most intractable problems of private sector development in Europe and Central Asia: how to facilitate reorganization and liquidation bankruptcies; how to promote small and medium enterprise spin-offs and new start-ups; and how to promote new learning at the enterprise level, both in the form of"Marshall Plan"programs with more advanced post-socialist countries, as well as continuous improvement programs (such as those adapted from Japanese programs). The prime mover for these programs is the quasi-public restructuring agency, ARIA, which was established as part of the Moldova Private Sector Development I loan. ARIA was structured to try to combine private sector entrepreneurship with a public function in the process of restructuring and bankruptcy. The study tries to account for the strategies and innovations that lead to results. And it tries to connect the ARIA strategy to past development literature by viewing the study through Albert Hirschman's work on social learning and change.Enterprise Development&Reform,Public Health Promotion,Banks&Banking Reform,Health Monitoring&Evaluation,Small Scale Enterprise,Health Monitoring&Evaluation,Banks&Banking Reform,Small Scale Enterprise,Microfinance,Private Participation in Infrastructure
Does Indonesia have a"low-pay"civil service?
No full textGovernment officials and polcy analysts maintain that Indonesia's civil servants are poorly paid and have been for decades. This conclusion is supported by anecdotal evidence and casual empiricism. The authors systematically analyze the realtionship between government and private compensation levels using data from two large household surveys carried out by Indonesia's Central Bureau of Statistics: the 1998 Sakernas and 1999 Susenas. The results suggest that government workers with a high school education or less, representing three-quarters of the civil service, earn a pay premium over their private sector counterparts. Civil servants with more than a high school education earn less than they would in the private sector but, on average, the premium is far smaller than commonly is alleged and is in keeping with public/private differentials in other countries. These results prove robust to varying econometric specifications and cast doubt on low pay as an explanation for government corruption.Decentralization,Public Health Promotion,Health Monitoring&Evaluation,National Governance,Knowledge Economy,Health Monitoring&Evaluation,NationalGovernance,Knowledge Economy,Education for the Knowledge Economy,Parliamentary Government
With the help of one's neighbors - externalities in the production of nutrition in Peru
No full textBoth public, and private resources contribute to children's nutritional status. And investments by one household may improve health in other neighborhood households, by improving the sanitation environment, and increasing shared knowledge. The authors measure the externalities of investments in nutrition, by indicatingthe impact of women's education in Peruvian neighborhoods, on children's nutrition in other households, after controlling for those households'education, and income. They find that in rural areas this shared knowledge has a significant impact on nutrition. The coefficient of an increase in the average education in the neighborhood is appreciably larger than the coefficient of education in isolation. That is, educating women in rural areas, improves all children's nutritional status, even for those whose caregivers are themselves not educated. In both urban, and rural areas, they observe externalities from investments in sanitation made by neighboring households. They do not find the same externalities in the case of investments, only in the household water supply. There is a direct link between the caregivers'education, and their children's health status. Education transmits information about health, and nutrition. It teaches numeracy, and literacy, which help caregivers read labels, and instructions. Bu exposing caregivers to new environments, it makes them receptive to modern medical treatment. It gives women the confidence to participate in decision-making within a household, and it gives men, and women the confidence to interact with health care professionals.Health Economics&Finance,Urban Services to the Poor,Urban Services to the Poor,Decentralization,Public Health Promotion,Urban Services to the Poor,Urban Services to the Poor,Health Economics&Finance,Water Supply and Sanitation Governance and Institutions,Town Water Supply and Sanitation
Health insurance reform in four Latin American countries : theory and practice
No full textThe author examines public economics rationales for public intervention in health insurance markets, draws on the literature of organizational design to examine alternative intervention strategies, and considers health insurance reforms in four Latin American countries -- Argentina, Brazil, Chile, and Colombia -- in light of the theoretical literature. Equity has been the main reason for large-scale public intervention in the health insurance sector, despite the well-known failures of insurance and health care markets associated with imperfect information. Recent reforms have sought less to make private markets more efficient than to make public provision more efficient, sometimes by altering the focus and function of existing institutions (such as the obras sociales in Argentina) or by encouraging the growth of new ones (such as Chile's ISAPREs). Generally, these four Latin American countries have reformed the ways insurance and care are organized and delivered, have tried to extend formal coverage to previously marginalized groups, and have tried to finance this extension fairly. Colombia instituted an implicit two-tiered voucher scheme financed through a proportional wage tax. Chile's financing mechanism is similar but the distribution of benefits is less progressive, so the net effect is less redistributive. Argentina's remodeled obras system went halfway: the financing base is similar and there is some implicit redistribution from richer to poorer obras, but the quality of insurance increases with income. On the face of it, Brazil's health insurance system is less redistributive than those of the other three countries, as no tax is earmarked for financing health insurance. But taxes paid by higher-income taxpayers are not reduced when they choose private insurance, highlighting the problem of examining the health sector independent of the general tax and transfer system.Health Economics&Finance,Environmental Economics&Policies,Insurance&Risk Mitigation,Insurance Law,Economic Theory&Research
Gas gains over 104 and optimisation using 55Fe X-rays in low pressure SF6 with a novel Multi-Mesh ThGEM for directional dark matter searches
No full textThe Negative Ion Drift (NID) gas SF6 has favourable properties for track reconstruction in directional Dark Matter (DM) searches utilising low pressure gaseous Time Projection Chambers (TPCs). However, the electronegative nature of the gas means that it is more difficult to achieve significant gas gains with regular Thick Gaseous Electron Multipliers (ThGEMs). Typically, the maximum attainable gas gain in SF6 and other Negative Ion (NI) gas mixtures, previously achieved with an 55Fe X-ray source or electron beam, is on the order of 103 [1,2,3,4]; whereas electron drift gases like CF4 and similar mixtures are readily capable of reaching gas gains on the order of 104 or greater [5,9,7,8,6]. In this paper, a novel two stage Multi-Mesh ThGEM (MMThGEM) structure is presented. The MMThGEM was used to amplify charge liberated by an 55Fe X-ray source in 40 Torr of SF6. By expanding on previously demonstrated results [10], the device was pushed to its sparking limit and stable gas gains up to ˜50000 were observed. The device was further optimised by varying the field strengths of both the collection and transfer regions in isolation. Following this optimisation procedure, the device was able to produce a maximum stable gas gain of ˜90000. These results demonstrate an order of magnitude improvement in gain with the NID gas over previously reported values and ultimately benefits the sensitivity of a NITPC to low energy recoils in the context of a directional DM search
Charge amplification in sub-atmospheric CF4:He mixtures for directional dark matter searches
No full textLow pressure gaseous Time Projection Chambers (TPCs) are a viable technology for directional Dark Matter (DM) searches and have the potential for exploring the parameter space below the neutrino fog [1,2]. Gases like CF4 are advantageous because they contain flourine which is predicted to have heightened elastic scattering rates with a possible Weakly Interacting Massive Particle (WIMP) DM candidate [3,4,5]. The low pressure of CF4 must be maintained, ideally lower than 100 Torr, in order to elongate potential Nuclear Recoil (NR) tracks which allows for improved directional sensitivity and NR/Electron Recoil (ER) discrimination [6]. Recent evidence suggests that He can be added to heavier gases, like CF4, without significantly affecting the length of 12C and 19F recoils due to its lower mass. Such addition of He has the advantage of improving sensitivity to lower mass WIMPs [1]. Simulations can not reliably predict operational stability in these low pressure gas mixtures and thus must be demonstrated experimentally. In this paper we investigate how the addition of He to low pressure CF4 affects the gas gain and energy resolution achieved with a single Thick Gaseous Electron Multiplier (ThGEM)
Test of low radioactive molecular sieves for radon filtration in SF6 gas-based rare-event physics experiments
No full textType 5 Å molecular sieves (MS) have been demonstrated to remove radon from SF6 gas. This is important for ultra-sensitive SF6 gas-based directional dark matter and related rare-event physics experiments, as radon can provide a source of unwanted background events. Unfortunately, commercially available sieves intrinsically emanate radon at levels not suitable for ultra-sensitive physics experiments. A method to produce a low radioactive MS has been developed in Nihon University (NU). In this work, we explore the feasibility of the NU-developed 5 Å type MS for use in such experiments. A comparison with a commercially available Sigma-Aldrich 5 Å type MS was made. The comparison was done by calculating a parameter indicating the amount of radon intrinsically emanated by the MS per unit radon captured from SF6 gas. The measurements were made using a specially adapted DURRIDGE RAD7 radon detector. The NU-developed 5 Å MS emanated radon up to 61 ± 9% less per radon captured (2.1 ± 0.1) × 10−3, compared to the commercial Sigma-Aldrich MS (5.4 ± 0.4) × 10−3, making it a better candidate for use in a radon filtration setup for future ultra-sensitive SF6 gas based experiments
