20,710 research outputs found
Methanol detection in M82
We present a multilevel study of the emission of methanol, detected for the
first time in this galaxy, and discuss the origin of its emission. The high
observed methanol abundance of a few 10^-9 can only be explained if injection
of methanol from dust grains is taken into account. While the overall
[CH3OH]/[NH3] ratio is much larger than observed towards other starbursts, the
dense high excitation component shows a similar value to that found in NGC 253
and Maffei 2. Our observations suggest the molecular material in M 82 to be
formed by dense warm cores, shielded from the UV radiation and similar to the
molecular clouds in other starbursts, surrounded by a less dense
photodissociated halo. The dense warm cores are likely the location of recent
and future star formation within M 82.Comment: Accepted for publication in A&A Letter
The effect of pension rules on retirement monetary incentives with an application to pension reforms in Spain
In this work we theoretically disentangle the effects of pension provisions on a variety of financial incentives to retirement, trying to reconcile them with some key Spanish retirement patterns. We find that the "average" individual, who is never affected by any cap of contributions or benefits, has weak incentives to retire early and strong incentives to retire at the normal retirement age. Alternatively, individuals at the bottom of the wage distribution have strong incentives to retire as early as possible, because ot the interaction between age-related penalties and the minimun pension. Both findings perfectly accommodate the retirement hazard of medium and low earners respectively. In contrast, high earners (those that have their contributions capped) despite having strong incentives to retire at the Early Retirement Age, do not do so. This is because, for those workers, financial incentives are not a good proxy for the marginal utility from working. Finally, we analyze the reasons behind the failure of the 1997 reform in improving the sustainability of the Spanish public pension system
The effect of pension rules on retirement monetary incentives with an application to pension reforms in Spain.
In this work we theoretically disentangle the effects of pension provisions on a variety of financial incentives to retirement, trying to reconcile them with some key Spanish retirement patterns. We find that the "average" individual, who is never affected by any cap of contributions or benefits, has weak incentives to retire early and strong incentives to retire at the normal retirement age. Alternatively, individuals at the bottom of the wage distribution have strong incentives to retire as early as possible, because ot the interaction between age-related penalties and the minimun pension. Both findings perfectly accommodate the retirement hazard of medium and low earners respectively. In contrast, high earners (those that have their contributions capped) despite having strong incentives to retire at the Early Retirement Age, do not do so. This is because, for those workers, financial incentives are not a good proxy for the marginal utility from working. Finally, we analyze the reasons behind the failure of the 1997 reform in improving the sustainability of the Spanish public pension system.
The effect of pension rules on retirement monetary incentives with an application to pension reforms in Spain
In this work we theoretically disentangle the effects of pension provisions on a variety of financial incentives to retirement, trying to reconcile them with some key Spanish retirement patterns. We find that the «average» individual, who is never affected by any cap of contributions or benefits, has weak incentives to retire early and strong incentives to retire at the normal retirement age. Alternatively, individuals at the bottom of the wage distribution have strong incentives to retire as early as possible, as a result of the interaction between age-related penalties and the minimum pension. Both findings perfectly accommodate the retirement hazard of medium and low earners respectively. In contrast, high earners (those that have their contributions capped) do not retire early despite having strong incentives to do so. This is because, for those workers, financial incentives are not a good proxy for the marginal utility from working. Finally, we analyze the reasons behind the failure of the 1997 reform in improving the sustainability of the Spanish public pension system.retirement, Social Security, Monetary incentives, Pension Reform, Spain
An evaluation of the life-cycle effects of minimum pensions on retirement behaviour: Extended Version
In this paper we explore the effects of the minimum pension program on welfare and retirement in Spain. This is done with a stylized life-cycle model which provides a convenient analytical characterization of optimal behavior. We use data from the Spanish Social Security to estimate the behavioral parameters of the model and then simulate the changes induced by the minimum pension in aggregate retirement patterns. The impact is substantial: there is a threefold increase in retirement at 60 (the age of first entitlement) with respect to the economy without minimum pensions, and total early retirement (before or at 60) is almost 50% larger.Retirement, life cycle model, minimum pension, structural estimation
Endogenous retirement and public pension system reform in Spain
All around the world , developed countries have resorted to parametric reforms of their Social Security systems, in an attempt to lessen the impact of the population aging. In particular, pension formulae have been modified to reduce the generosity of the systems and to induce longer working careers. In this paper we explore the capacity of these reforms to alleviate the expected financial difficulties of current PAYG systems. This is accomplished by developing and Heterogeneous Agents, Applied General Equilibrium model where individuals can freely adjust their retirement ages in response to the incentives provided by the pension regulations. This inclusion is relevant, as parametric changes tend to significantly alter retirement incentives. We find that the calibrated model successfully reproduces the basic stylized facts of retirement behavior in Spain. In particular, it mimics the early retirement pattern of low income workers under the effects of minimum pensions. The model is then used to explore the effects of several changes in pension formula, including the reform actually implemented in 1997. The general conclusion is that parametric changes can significantly improve the financial condition of the system, but are far away from being able to fully restoring it
Endogenous Retirement and Public Pension System Reform in Spain
All around the world, population aging has spurred developed countries to reform their PAYG pension systems. In particular, delaying legal retirement ages and reducing the generosity of pension benefits have been widely implemented changes. In this paper we assess how successful those policies can be in the case of the Spanish economy, and compare with the results obtained by the already implemented reforms (1997 and 2001). This evaluation is accomplished in a heterogeneous-agents, applied general equilibrium model where individuals can adjust their retirement ages in response to changes in pension rules. We check the ability of the model to reproduce the basic stylized facts of retirement behavior (specially the pattern of early retirement induced by minimum pensions). We then use to model to explore the impact of pension reforms. We find that already implemented changes actually increase the implicit liabilities of the system, while delaying the legal retirement age to 68 may roughly halve the size of the current pension debt.Pension System Reform, Applied General Equilibrium, Retirement.
Hokupa'a-Gemini Discovery of Two Ultracool Companions to the Young Star HD 130948
We report the discovery of two faint ultracool companions to the nearby
(d~17.9 pc) young G2V star HD 130948 (HR 5534, HIP 72567) using the Hokupa'a
adaptive optics instrument mounted on the Gemini North 8-meter telescope. Both
objects have the same common proper motion as the primary star as seen over a 7
month baseline and have near-IR photometric colors that are consistent with an
early-L classification. Near-IR spectra taken with the NIRSPEC AO instrument on
the Keck II telescope reveal K I lines, FeH, and water bandheads. Based on
these spectra, we determine that both objects have spectral type dL2 with an
uncertainty of 2 spectral subclasses. The position of the new companions on the
H-R diagram in comparison with theoretical models is consistent with the young
age of the primary star (<0.8 Gyr) estimated on the basis of X-ray activity,
lithium abundance and fast rotation. HD 130948 B and C likely constitute a pair
of young contracting brown dwarfs with an orbital period of about 10 years, and
will yield dynamical masses for L dwarfs in the near future.Comment: 10 pages, 3 figures, (13 total pages
Dynamical variables in Gauge-Translational Gravity
Assuming that the natural gauge group of gravity is given by the group of
isometries of a given space, for a maximally symmetric space we derive a model
in which gravity is essentially a gauge theory of translations. Starting from
first principles we verify that a nonlinear realization of the symmetry
provides the general structure of this gauge theory, leading to a simple choice
of dynamical variables of the gravity field corresponding, at first order, to a
diagonal matrix, whereas the non-diagonal elements contribute only to higher
orders.Comment: 15 page
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