Home Ownership, Job Duration, and Wages

We investigate the impact of home ownership on individual job mobility and wages in Denmark. We find that home ownership has a negative impact on job-to-job mobility both in terms of transition into new local jobs and new jobs outside the local labour market. In addition, there is a clear negative effect of home ownership on the unemployment risk and a positive impact on wages. These results are robust to different strategies for correcting for the possible endogeneity of the home owner variable.home ownership; job mobility; duration model

A study of 23Na and 12C

Progress report for first part of Ph.D. studies. Describes my work on the DAQ for Aarhus 5MV accelerator. A newly developed analysis and simulation library for small scale DSSD experiments. Futhermore, an experimental study of 23Na(a,p) and it implications are discussed. Ultimately, an experiment for determining the 12B beta-branching ratio to the Hoyle state using Gammasphere is discussed

Are Home Owners Really more Unemployed?

This paper investigates the effect of home ownership on labour mobility and unemployment duration. We distinguish between finding employment locally, or by being geographically mobile. We find that home ownership hampers the propensity to move for job reasons but improves the chances of finding local jobs, which is in accordance with the predictions from our theoretical model. The overall hazard rate into employment is higher for homeowners, such that there is a negative correlation between home ownership and unemployment duration. Our empirical findings thus lend some support for the main mechanism behind the so-called Oswald hypothesis, even if it does not find positive correlation between unemployment duration and home ownership at the individual level.home ownership; labour mobility; unemployment duration

Measurement of the full excitation spectrum of the 7Li(p,{\gamma}){\alpha}{\alpha} reaction at 441 keV

A current challenge for ab initio calculations is systems that contain large continuum contributions such as 8Be. We report on new measurements of radiative decay widths in this nucleus that test recent Green's function Monte Carlo calculations. Traditionally, {\gamma} ray detectors have been utilized to measure the high energy photons from the 7Li(p, {\gamma}){\alpha}{\alpha} reaction. However, due to the complicated response function of these detectors it has not yet been possible to extract the full {\gamma} ray spectrum from this reaction. Here we present an alternative measurement using large area Silicon detectors to detect the two {\alpha} particles, which provides a practically background free spectrum and retains good energy resolution. The resulting spectrum is analyzed using a many-level multi channel R-matrix parametrization. Improved values for the radiative widths are extracted from the R-matrix fit. We find evidence for significant non-resonant continuum contributions and tentative evidence for a broad 0+ resonance at 12 MeV.Comment: Accepted version. Fixed Fig. 5 ordinate label

Failure Filtrations for Fenced Sensor Networks

In this paper we consider the question of sensor network coverage for a 2-dimensional domain. We seek to compute the probability that a set of sensors fails to cover given only non-metric, local (who is talking to whom) information and a probability distribution of failure of each node. This builds on the work of de Silva and Ghrist who analyzed this problem in the deterministic situation. We first show that a it is part of a slightly larger class of problems which is #P-complete, and thus fast algorithms likely do not exist unless P$=$NP. We then give a deterministic algorithm which is feasible in the case of a small set of sensors, and give a dynamic algorithm for an arbitrary set of sensors failing over time which utilizes a new criterion for coverage based on the one proposed by de Silva and Ghrist. These algorithms build on the theory of topological persistence

Tropical Feynman integration in the physical region

The software feyntrop for direct numerical evaluation of Feynman integrals is presented. We focus on the underlying combinatorics and polytopal geometries facilitating these methods. Especially matroids, generalized permutohedra and normality are discussed in detail.Comment: 9 pages, 3 figures, EPS-HEP 2023 proceeding

A study of 8Be, 12C and 27Al with state-of-the-art detector arrays

This thesis reports on the results of four different experiments carried out at either Argonne National Laboratory or Aarhus University. The first experiment was a cross section measurement of the 23 Na(α, p) reaction at astrophysical energies. This reaction acts as a proton source for the 25 Mg(p, γ) 26 Al reaction in asymptotic giant branch stars and 26 Al is an direct observable of ongoing nucleosynthesis. Prior to this experiment a different group published the suprising result, that the cross section should be scaled up by a factor of 40. However, the present experiment was unable to reproduce this, and was instead a confirmation of the established statistical model. The second experiment was a measurement of the β feeding of the Hoyle state from the 12 B ground state. This experiment was carried out at Gammasphere in order to provide independent confirmation of a previous result obtained using charged particle spectroscopy, which disagreed from measurement performed in the seventies by roughly a factor of 2. The value of β feeding is an important constraint in the β decay studies of the 2 + excitation of the Hoyle state. The result of the present experiment was a confirmation of the previous result. In the third experiment the 8 Be excitation spectrum, following the γ decay of the 17.6 MeV 1 + state, was measured using charged particles. This technique yields unparalleled detection efficiency, resolution, and dynamic range allowing the resulting spectrum to be analyzed using R-matrix theory. The results of this analysis were improved γ decay widths and a tentative broad 0 + resonance at 12 MeV. The last experiment was a measurement of the 11 B(p, 3α) cross section at an energy corresponding to the 16.1 MeV 2 + state in 12 C. For this state there exist multiple inconsistent measurements of its decay properties, and a majority of these inconsistencies can be traced to ambiguities in the nor- malization. With this experiment the normalization issue was circumvented by measuring the final state in full kinematics. The result was an improved cross section for this resonance and a suggestion to rescale the recommended cross section for 11 B(p, 3α) by a factor of 2/3 over the full energy range. This impacts the recommended reaction rate by NACRE and NACRE II, which should be scaled by roughly a factor of 2. In addition to these experiments, this thesis reports on the technical development carried out at Aarhus University. Specifically, an analysis library for the analysis of nuclear physics experiment with silicon detectors was developed. This library is built on the concept of an analysis pipeline. Secondly, the Aarhus data acquisition has been rebuilt from the ground up. The different components and recent development allowing significantly higher rates will be presented

Experimental study of the 11B(p,3α)γ^{11}\text{B}(p,3\alpha)\gamma reaction at Ep=0.5−2.7E_p = 0.5-2.7 MeV

Our understanding of the low-lying resonance structure in $^{12}$C remains incomplete. We have used the $^{11}\text{B}(p,3\alpha)\gamma$ reaction at proton energies of $E_p=0.5-2.7$ MeV as a selective probe of the excitation region above the $3\alpha$ threshold in $^{12}$C. Transitions to individual levels in $^{12}$C were identified by measuring the 3$\alpha$ final state with a compact array of charged-particle detectors. Previously identified transitions to narrow levels were confirmed and new transitions to broader levels were observed for the first time. Here, we report cross sections, deduce partial $\gamma$-decay widths and discuss the relative importance of direct and resonant capture mechanisms.Comment: 9 pages, 7 figures, 5 tables; added details on data analysi