182 research outputs found

    Incentive Effects of Unemployment Insurance Savings Accounts: Evidence from Chile

    Get PDF
    This study examines the determinants of job-finding rates of unemployment benefit recipients under the Chilean program. This is a unique, innovative program that combines social insurance through a solidarity fund (SF) with self-insurance in the form of unemployment insurance savings accounts (UISAs) - so as to mitigate the moral hazard problem of traditional unemployment insurance programs. Our study is the first one to empirically investigate whether UISAs improve work incentives. We find that for beneficiaries using the SF, the pattern of job finding rates over the duration of unemployment is consistent with moral hazard effects, while for beneficiaries relying on UISAs, the pattern is free of such effects. We also find that for benefit recipient not entitled to use the SF, the amount of accumulation on the UISA does not affect the exit rate from unemployment, suggesting that such individuals internalize the costs of unemployment benefts. Our results provide strong support to the idea that UISAs can improve work incentives.Unemployment insurance;unemployment duration;savings accounts

    Incentive Effects of Unemployment Insurance Savings Accounts:Evidence from Chile

    Get PDF
    This study examines the determinants of job-finding rates of unemployment benefit recipients under the Chilean program. This is a unique, innovative program that combines social insurance through a solidarity fund (SF) with self-insurance in the form of unemployment insurance savings accounts (UISAs) - so as to mitigate the moral hazard problem of traditional unemployment insurance programs. Our study is the first one to empirically investigate whether UISAs improve work incentives. We find that for beneficiaries using the SF, the pattern of job finding rates over the duration of unemployment is consistent with moral hazard effects, while for beneficiaries relying on UISAs, the pattern is free of such effects. We also find that for benefit recipient not entitled to use the SF, the amount of accumulation on the UISA does not affect the exit rate from unemployment, suggesting that such individuals internalize the costs of unemployment benefts. Our results provide strong support to the idea that UISAs can improve work incentives.

    Road environment modeling using robust perspective analysis and recursive Bayesian segmentation

    Get PDF
    Recently, vision-based advanced driver-assistance systems (ADAS) have received a new increased interest to enhance driving safety. In particular, due to its high performance–cost ratio, mono-camera systems are arising as the main focus of this field of work. In this paper we present a novel on-board road modeling and vehicle detection system, which is a part of the result of the European I-WAY project. The system relies on a robust estimation of the perspective of the scene, which adapts to the dynamics of the vehicle and generates a stabilized rectified image of the road plane. This rectified plane is used by a recursive Bayesian classi- fier, which classifies pixels as belonging to different classes corresponding to the elements of interest of the scenario. This stage works as an intermediate layer that isolates subsequent modules since it absorbs the inherent variability of the scene. The system has been tested on-road, in different scenarios, including varied illumination and adverse weather conditions, and the results have been proved to be remarkable even for such complex scenarios

    3-D Respiratory Motion Compensation during EP Procedures by Image-Based 3-D Lasso Catheter Model Generation and Tracking

    Full text link
    Abstract. Radio-frequency catheter ablation of the pulmonary veins attached to the left atrium is usually carried out under fluoroscopy guidance. Two-dimensional X-ray navigation may involve overlay im-ages derived from a static pre-operative 3-D volumetric data set to add anatomical details. However, respiratory motion may impair the utility of static overlay images for catheter navigation. We developed a system for image-based 3-D motion estimation and compensation as a solution to this problem for which no previous solution is yet known. It is based on 3-D catheter tracking involving 2-D/3-D registration. A biplane X-ray C-arm system is used to image a special circumferential (lasso) catheter from two directions. In the first step of the method, a 3-D model of the device is reconstructed. 3-D respiratory motion at the site of ablation is then estimated by tracking the reconstructed model in 3-D from bi-plane fluoroscopy. In our experiments, the circumferential catheter was tracked in 231 biplane fluoro frames (462 monoplane fluoro frames) with an average 2-D tracking error of 1.0 mm ± 0.5 mm.

    Pre-M Phase-promoting Factor Associates with Annulate Lamellae in Xenopus Oocytes and Egg Extracts

    Get PDF
    We have used complementary biochemical and in vivo approaches to study the compartmentalization of M phase-promoting factor (MPF) in prophase Xenopus eggs and oocytes. We first examined the distribution of MPF (Cdc2/CyclinB2) and membranous organelles in high-speed extracts of Xenopus eggs made during mitotic prophase. These extracts were found to lack mitochondria, Golgi membranes, and most endoplasmic reticulum (ER) but to contain the bulk of the pre-MPF pool. This pre-MPF could be pelleted by further centrifugation along with components necessary to activate it. On activation, Cdc2/CyclinB2 moved into the soluble fraction. Electron microscopy and Western blot analysis showed that the pre-MPF pellet contained a specific ER subdomain comprising "annulate lamellae" (AL): stacked ER membranes highly enriched in nuclear pores. Colocalization of pre-MPF with AL was demonstrated by anti-CyclinB2 immunofluorescence in prophase oocytes, in which AL are positioned close to the vegetal surface. Green fluorescent protein-CyclinB2 expressed in oocytes also localized at AL. These data suggest that inactive MPF associates with nuclear envelope components just before activation. This association may explain why nuclei and centrosomes stimulate MPF activation and provide a mechanism for targeting of MPF to some of its key substrates

    Multiple excitation modes in Hf 163

    Get PDF
    Excited states of Hf163 were populated using the Zr94(Ge74,5n) reaction and the decay γ rays were measured with the Gammasphere spectrometer. Two previously known bands were extended to higher spins, and nine new bands were identified. In addition to bands associated with three- and five-quasiparticle configurations, two γ-vibrational bands coupled to the i13/2 excitation were also observed. The lowest level of a newly identified, negative-parity band is proposed to be the ground state of the nucleus. A systematic delay of the high-spin proton crossing frequency with increasing quadrupole deformation from Hf162 to Hf172 was established. Extensive band searches failed to reveal a triaxial, strongly deformed structure in Hf163 similar to the one observed in several nuclei around A∼165

    Reply to: Possible overestimation of isomer depletion due to contamination

    Get PDF
    We appreciate the interest of Guo et al., the points that they raise, and the opportunity that we have to provide additional details that are not included in ref. This allows us to strengthen our experimental case while, in parallel, recent developments are improving our theoretical understanding of nuclear excitation by electron capture (NEEC), such as the exploration of a substantial increase in predicted NEEC probability when considering capture by an ion in an excited state (S. Gargiulo et al., submitted) or the impact of the momentum distribution of target electrons (J.R. et al., submitted). In the accompanying Comment, Guo et al. focus on whether potential background contributions were underestimated in our analysis. As discussed below, these concerns are mostly unwarranted; aside from a small systematic uncertainty that could possibly slightly reduce our reported NEEC excitation probability of Pexc = 0.010(3), our original conclusions still stand

    Isomer depletion as experimental evidence of nuclear excitation by electron capture

    Get PDF
    The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a 3-ray. This 'internal conversion' has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process - nuclear excitation by electron capture (NEEC) - a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of 'isomer depletion', which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC
    corecore