A5088720157- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Labor market dynamics and wage inequality
- Gender, Labor, and Family Dynamics
- Nuclear Physics and Applications
- Retirement, Disability, and Employment
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Financial Literacy, Pension, Retirement Analysis
- Employment and Welfare Studies
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Work-Family Balance Challenges
- Galaxies: Formation, Evolution, Phenomena
- Global Health Care Issues
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Fiscal Policy and Economic Growth
- Economic theories and models
- Radio Astronomy Observations and Technology
Icahn School of Medicine at Mount Sinai
2024-2025
Vrije Universiteit Amsterdam
2011-2023
Tinbergen Institute
2010-2022
Amsterdam UMC Location Vrije Universiteit Amsterdam
2006-2022
Space Research Organisation Netherlands
1997-2018
Network for Studies on Pensions, Aging and Retirement
2006-2018
IZA - Institute of Labor Economics
2006-2018
University of Amsterdam
1993-2013
Leiden Observatory
1992-2008
Tilburg University
1992-2005
We have used observations of Cyg X-1 from the Compton Gamma Ray Observatory and BeppoSAX to study variation in MeV γ-ray emission between hard soft spectral states, using spectra that cover energy range 20 keV up 10 MeV. These data provide evidence for significant variability at energies above 1 In particular, whereas X-ray flux decreases during state, increases, resulting a significantly harder spectrum This behavior is consistent with general picture galactic black hole candidates having...
The imaging Compton telescope COMPTEL aboard NASA's Gamma-Ray Observatory has opened the MeV gamma-ray band as a new window to astronomy. provided first complete all-sky survey in energy range 0.75 30 MeV. catalogue, presented here, is largely restricted published results. It contains firm well marginal detections of continuum and line emitting sources presents upper limits for various types objects. numbers most significant are 32 steady 31 bursters. Among sources, detected so far,...
In the 1960s, novel and increasingly powerful observational techniques opened up field of high-energy astrophysics. Cosmology started to become an empirical science, there was a resurgence in study general relativity. Martin Rees became ...Read More
Abstract This paper estimates the impact of early retirement on mortality using Dutch administrative micro panel data. An unexpected temporary decrease in eligibility age for benefits civil servants is used to instrument choice. We find that induced decreased probability a man dies within 5 years by 2.6 percentage points. The result robust alternative specifications and data selection criteria.
We report the detection of both 67.9 and 78.4 keV 44Sc γ-ray lines in Cassiopeia A with INTEGRAL IBIS/ISGRI instrument. Besides robustness provided by spectroimaging observations, main improvements compared to previous measurements are a clear separation two together an improved significance hard X-ray continuum up 100 keV. These allow us refine determination 44Ti yield constrain nature nonthermal emission. By combining COMPTEL, BeppoSAX PDS ISGRI measurements, we find line flux (2.5 ± 0.3)...
The literature suggests that in Italy husbands contribute less to unpaid household work than any other European country, while women have the lowest market employment rates. Here we examine time allocation of Italian couples on which there are surprisingly few studies date. We analyze simultaneously allocated by husband and wife work, childcare housework, allowing for various interactions. use data drawn from national Time Use Survey 2002–2003 analysis. find spousal is sensitive personal...
We investigate the relationship between financial wealth, reservation wages, and labor market transitions. Wealth is assumed to affect level of wage employment probability. test for validity this assumption by estimating a simultaneous‐equations model transitions, wealth. The data used analysis relate sample unemployed job searchers. use subjective information on wage. found have significantly positive impact overall wealth probability negative though small.
The Compton Gamma Ray Observatory (CGRO) has observed the Cygnus region on several occasions since its launch in 1991. data collected by COMPTEL experiment CGRO represent most sensitive observations to date of X-1 0.75-30 MeV range. A spectrum accumulated over 10 weeks observation time shows significant evidence for emission extending out MeV. We have combined these with contemporaneous from both BATSE and OSSE produce a broadband γ-ray spectrum, corresponding low X-ray state X-1, 50 keV up...
We report the detection of 44Sc nuclear decay lines at 67.9 and 78.4 keV associated with 44Ti in Cassiopeia A. The line emission was observed by Phoswich Detection System instrument on board BeppoSAX, which recently supernova remnant for over 500 ks. a flux (2.1 ± 0.7) × 10-5 photons cm-2 s-1 each (90% confidence) is 5 σ significance level, if we can assume that 12-300 continuum adequately represented single power law. However, as nature not clear, investigate various other possibilities. A...
One of the reasons for setting up an unemployment insurance scheme is to allow job losers smooth consumption. We test impact benefits on changes in household food expenditure individuals who have recently experienced a loss. also study relationship between and financial wealth unemployed. From our empirical analysis we conclude that, households without at time loss, help For running debt before there evidence that lower replacement rates lead postponement repayment.
A structural empirical job search model is presented that incorporates the labor supply decision of individuals. The arrival a offer modeled as random draw from wage‐hours distribution. Subjective information used on desired working hours to identify optimal offered hours. Policy simulations are performed address several policy questions: Does decrease in unemployment benefits lead acceptance jobs with less preferred hours? How does length standard week affect behavior unemployed?
Theoretical models predict a positive effect of the level private wealth on retirement. In many countries, there is trend towards introduction more individual freedom choice in pension schemes. The will become an increasingly important factor retirement decision. Empirical analysis behaviour elderly workers so far has concentrated properties system. For sample male Netherlands, we empirically analyse rate. We find evidence for (early)
Abstract Background Anti-integrin αvβ6 autoantibodies (anti-αvβ6) are present in up to 90% of ulcerative colitis (UC) patients and predate disease development, but there is a paucity data regarding anti-αvβ6 Crohn’s (CD). We hypothesized that would be colonic CD given the shared biological characteristics with UC. Methods measured IgG peripheral blood samples from seven distinct cohorts representing diverse ethnic backgrounds, geographical locations stages including preclinical, incident...
The COMPTEL telescope on board the Compton Gamma‐Ray Observatory (CGRO) is capable of imaging gamma‐ray line sources in MeV region at a sensitivity order 10−5 photons/(cm2s). During two observation periods July 1992 and February 1993 Galactic plane young supernova remnant Cas A was observed. Imaging spectral analyses show evidence for emission 44Ti 1.16 from position significance level ∼4 σ.This first time has been detected decay. If placed 2.8 kpc then measured flux can be translated into...
Abstract In this paper we present an empirical structural job search model with endogenously determined intensity. The describes both the behaviour of unemployed seekers and on-the-job search. We use data on various indicators for intensity to study influence labour market transitions. estimation results give us insight in effectiveness impact benefit level is quantified. Moreover, are used gain 'discouraged worker' effect.
view Abstract Citations (51) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Gamma-Ray Constraint on the Nature of Dark Matter Silk, Joseph ; Bloemen, Hans If even a small component Galactic spheroid consists weakly interacting majorana fermions that are cold-dark-matter candidate particles for halo, there should be substantial flux annihilation gamma rays from source about 1-deg extent at center. COS B observations already constrain halo...
I present a structural empirical model of collective household labour supply that includes the non‐participation decision. specify simultaneous for hours, participation and wages husband wife. discuss problems identification statistical coherency arise in application model. The random effects it is estimated using panel data set Dutch couples. estimates allow me to check underlying regularity conditions on individual preferences obtain sharing rule governs division income between
Abstract We consider a utility‐consistent static labor supply model with flexible preferences and nonlinear possibly non‐convex budget set. Stochastic error terms are introduced to represent optimization reporting errors, stochastic preferences, heterogeneity in wages. Coherency conditions on the parameters support of distributions imposed for all observations. The complexity makes it impossible write down probability participation. Hence we use simulation techniques estimation. compare our...