1,250 research outputs found
Retirement Shares Plan: A New Model of Risk Sharing
Investment risk and longevity risk are borne by the plan sponsor in a defined benefit (DB) plan or by the plan participant in a defined contribution (DC) plan. By contrast, our proposed Retirement Shares Plan (RSP) allocates the longevity risk to the plan sponsor and investment risk to the plan participant. The RSP allows the participant sufficient control over the investment risk to tailor that risk to his specific circumstances. This allocation of risk provides predictable and stable cost to the plan sponsor with little chance of unfunded liabilities. The retiree receives lifetime income and potential inflation protection
Observations on Actuarial Assumptions and Models for Defined Benefit Pension Plans
The goal of this paper is to review and comment on certain aspects of the Pension Insurance Modeling System (PIMS) and certain actuarial assumptions used by PIMS. The apparent stability of the deficit and funding ratio of the PBGC are partially dependent on a continued stream of premium payments from plan sponsors. However, derisking and other trends among retirement plans may change the pattern of premium income. Deterministic projections that supplement the stochastic simulations may enhance the understanding of the current deficit and the projected net claims over the next ten years
A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522
We present results from the first Suzaku observation of the high-mass X-ray
binary 4U 1538-522. The broad-band spectral coverage of Suzaku allows for a
detailed spectral analysis, characterizing the cyclotron resonance scattering
feature at keV and the iron K line at
keV, as well as placing limits on the strengths of the iron K line and
the iron K edge. We track the evolution of the spectral parameters both in time
and in luminosity, notably finding a significant positive correlation between
cyclotron line energy and luminosity. A dip and spike in the lightcurve is
shown to be associated with an order-of-magnitude increase in column density
along the line of sight, as well as significant variation in the underlying
continuum, implying the accretion of a overdense region of a clumpy stellar
wind. We also present a phase-resolved analysis, with most spectral parameters
of interest showing significant variation with phase. Notably, both the
cyclotron line energy and the iron K line intensity vary significantly
with phase, with the iron line intensity significantly out-of-phase with the
pulse profile. We discuss the implications of these findings in the context of
recent work in the areas of accretion column physics and cyclotron resonance
scattering feature formation.Comment: 15 pages, 8 figures. Accepted to ApJ on 2 July 201
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Green signalling effects in the market for energy-efficient residential buildings
Empirical evidence from recent studies suggests that the price premium on energy-efficient buildings is potentially higher than the pure capitalisation of energy savings but the empirical evidence on the size of the non-savings components is scant. This study aims to fill this research gap by investigating whether the mandatory energy efficiency ratings for residential properties imply benefits that go beyond energy savings. Using a sample of several thousand apartment transactions from Helsinki, Finland, we first test if higher ratings were significantly associated with higher prices. In addition to a large number of property and neighbourhood characteristics, this dataset contains information on building-level energy usage which allows us to distinguish between the cost savings effect of energy consumption and the value of more intangible factors associated with the energy label. The hedonic model yields a statistically significant 3.3% price premium for apartments in the top three energy-efficiency categories and 1.5% when a set of detailed neighbourhood characteristics are included. When maintenance costs containing energy usage costs are added, a robust and significant price premium of 1.3% persists whereas no differentiation is found for the medium and lower rating categories. These findings may be indicative of energy-efficient buildings having signalling value – and therefore an additional incentive to invest in such buildings – for ‘green’ consumers. However, a favourable energy rating did not appear to speed up the sales process in the analysed market.RICS Research Trust, Turku School of Economics Support Foundation, Academy of Finland, Marjatta and Eino Kolli Foundation, KIINKO Foundation, Cambridge University Land Society (CULS)This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.apenergy.2016.07.07
Probing large-scale wind structures in Vela X-1 using off-states with INTEGRAL
Vela X-1 is the prototype of the class of wind-fed accreting pulsars in high
mass X-ray binaries hosting a supergiant donor. We have analyzed in a
systematic way ten years of INTEGRAL data of Vela X-1 (22-50 keV) and we found
that when outside the X-ray eclipse, the source undergoes several luminosity
drops where the hard X-rays luminosity goes below 3x10^35 erg/s, becoming
undetected by INTEGRAL. These drops in the X-ray flux are usually referred to
as "off-states" in the literature. We have investigated the distribution of
these off-states along the Vela X-1 ~8.9 d orbit, finding that their orbital
occurrence displays an asymmetric distribution, with a higher probability to
observe an off-state near the pre-eclipse than during the post-eclipse. This
asymmetry can be explained by scattering of hard X-rays in a region of ionized
wind, able to reduce the source hard X-ray brightness preferentially near
eclipse ingress. We associate this ionized large-scale wind structure with the
photoionization wake produced by the interaction of the supergiant wind with
the X-ray emission from the neutron star. We emphasize that this observational
result could be obtained thanks to the accumulation of a decade of INTEGRAL
data, with observations covering the whole orbit several times, allowing us to
detect an asymmetric pattern in the orbital distribution of off-states in Vela
X-1.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Society (5 pages, 3 figures). A few typos fixed to match the published
versio
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The spatial impact of employment centres on housing markets
The spatial impact of employment centres on housing markets. Spatial Economic Analysis. Local economic growth tends to affect neighbourhood house prices unevenly. It has been observed that prime locations experience price hikes far in excess of the surrounding local area. Yet, this phenomenon is not well captured by existing economic models. This research provides a model of spatial and temporal interactions between housing and employment markets. The results show that rapid growth of employment centres increases house prices in neighbouring locations even after adjusting for fundamentals. It is concluded that spatial clustering of companies creates an option value for existing and potential employees that goes beyond ease of access for commuting purposes.The authors thank the Higher Education Funding Council for England (HEFCE) for providing funding for a project which inspired this study
Best Practices for Preschool Music Education: Supporting Music‑Making Throughout the Day
Active engagement in music has numerous academic and social benefits for young children and music-making is included in many early childhood standards and preschool curricula. The purpose of this article is to provide quality resources for classroom teachers to use in providing music-making activities for young children, ages 3–5. Although teachers may use music in their classrooms, we provide resources and suggestions for more intentional and extended integration of music-making. Specifically, we identify best practices for preschool music education based on key standards and research as well as with common music pedagogies. We then turn to concrete examples of how teachers can implement these music best practices throughout the entire preschool day. We provide ideas and resources for whole-group activities, focusing on choice-time/center activities and ways to incorporate music activities in other academic areas as these seem to be of greater need for teachers. Finally, we use the stated best practices to review the alignment of a sample of commercially available preschool music curricula as an additional support for teachers
Polarization surveys of the Galaxy
We report on sensitive 21cm and 11cm polarization surveys of the Galactic
plane carried out with the Effelsberg 100-m telescope at arcmin angular
resolution and some related work. Highly structured polarized emission is seen
along the Galactic plane as well as up to very high Galactic latitudes. These
observations reflect Faraday effects in the interstellar medium. Polarized
foreground and background components along the line of sight, modified by
Faraday rotation and depolarization, add in a complex way. The amplitudes of
polarized emission features are highly frequency dependent. Small-scale
components decrease in amplitude rapidly with increasing frequency. We stress
the need for sensitive absolutely calibrated polarization data. These are
essential for baseline setting and a correct interpretation of small-scale
structures. Absolutely calibrated data are also needed to estimate the
high-frequency polarized background. A recent study of polarized emission
observed across the local Taurus-Auriga molecular cloud complexes indicates
excessive synchrotron emission within a few hundred parsecs. These results
suggest that possibly a large fraction of the Galactic high latitude total
intensity and polarized emission is of local origin.Comment: 6 pages with 2 PS figures. To be published in "Astrophysical
Polarized Backgrounds", eds. S. Cecchini, S. Cortiglioni, R. Sault and C.
Sbarra, AIP Conf. Pro
A 1.4 GHz radio continuum and polarization survey at medium Galactic latitudes: I. Observation and reduction technique
A radio continuum survey at medium Galactic latitudes with the Effelsberg
100-m telescope is being carried out at a centre frequency of 1.4 GHz in total
power and linear polarization. Areas up to +/- 20 degree of Galactic latitude
are now being observed at a sensitivity of 15 mK TB total intensity and 8 mK TB
in linear polarization with an angular resolution of 9'35. This paper describes
the observing and reduction technique applied which results in absolutely
calibrated maps. The methods are illustrated by examples of images from the
survey.Comment: 12 pages, 9 figures, Accepted for publication in Astronomy and
Astrophysics Supp. Se
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