Pensions, Education and Life Expectancy

In a two-period model with agent heterogeneity we analyze a pension reform toward a stronger link between contributions and benefits (as recently observed in several countries) in a pension system with a Bismarckian and a Beveridgian component. We show that such a policy change reduces the educational level in an economy. The life expectancy differential between skilled and unskilled individuals drives this result. Furthermore, we investigate the consequences on the intragenerational redistribution characteristics of the pension system – in the sense of the number of net-recipients relative to net-payers – as well as welfare effects.social security, education, life expectancy, pension reform, redistribution

Using an InGrid Detector to Search for Solar Chameleons with CAST

We report on the construction, operation experience, and preliminary background measurements of an InGrid detector, i.e. a MicroMegas detector with CMOS pixel readout. The detector was mounted in the focal plane of the Abrixas X-Ray telescope at the CAST experiment at CERN. The detector is sensitive to soft X-Rays in a broad energy range (0.3--10 keV) and thus enables the search for solar chameleons. Smooth detector operation during CAST data taking in autumn 2014 has been achieved. Preliminary analysis of background data indicates a background rate of $1-5\times 10^{-5}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1}$ above 2 keV and $\sim 3\times 10^{-4}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1}$ around 1 keV. An expected limit of $\beta_\gamma \lesssim 5\times 10^{10}$ on the chameleon photon coupling is estimated in case of absence of an excess in solar tracking data. We also discuss the prospects for future operation of the detector.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs, Zaragoza, June 22 to 26, 201

An InGrid based Low Energy X-ray Detector

An X-ray detector based on the combination of an integrated Micromegas stage with a pixel chip has been built in order to be installed at the CERN Axion Solar Telescope. Due to its high granularity and spatial resolution this detector allows for a topological background suppression along with a detection threshold below $1\,\text{keV}$. Tests at the CAST Detector Lab show the detector's ability to detect X-ray photons down to an energy as low as $277\,\text{eV}$. The first background data taken after the installation at the CAST experiment underline the detector's performance with an average background rate of $5\times10^{-5}\,/\text{keV}/\text{cm}^2/\text{s}$ between 2 and $10\,\text{keV}$ when using a lead shielding.Comment: 4 pages, 5 figures, Contributed to the 10th Patras Workshop on Axions, WIMPs and WISPs, CERN, June 29 to July 4, 201

Uniform Boundedness of S-Units in Arithmetic Dynamics

Let K be a number field and let S be a finite set of places of K which contains all the Archimedean places. For any f(z) in K(z) of degree d at least 2 which is not a d-th power in \bar{K}(z), Siegel's theorem implies that the image set f(K) contains only finitely many S-units. We conjecture that the number of such S-units is bounded by a function of |S| and d (independently of K and f). We prove this conjecture for several classes of rational functions, and show that the full conjecture follows from the Bombieri--Lang conjecture

Revealing the dynamics of a local Alpine windstorm using large-eddy simulations

The local atmospheric flow in mountainous terrain can be highly complex and deviate considerably from the ambient conditions. One example is a notorious local windstorm in a narrow and deep valley in north-eastern Switzerland, known as the Laseyer, that had previously even caused a train derailment. This windstorm is characterized by strong south-easterly winds blowing perpendicular to the valley axis during strong north-westerly ambient flow conditions. We investigate the mechanism of this local windstorm and its sensitivity to changes in the prescribed ambient wind using large-eddy simulation (LES). The LES are performed using the Portable Model for Multi-Scale Atmospheric Prediction (PMAP) at a horizontal grid spacing of 30 m and applying a terrain-following vertical coordinate with steep slopes of the real topography reaching nearly 80°. The simulations, driven by strong north-westerly ambient winds, successfully capture the flow reversal in the valley with quasi-periodically occurring short episodes of wind bursts regularly exceeding 20 m s-1 and in exceptional cases exceeding 35 m s-1. The flow reversal is explained by an amplifying interplay of (1) a recirculation region formed by flow separation in the lee of the upstream ridge, and (2) a vortex caused by a positive pressure anomaly formed by the north-westerly winds impinging on the downstream mountain. This formation mechanism is supported by a simulation in which the height of the downstream mountain is reduced, resulting in a decrease in the strength of the reversed in-valley flow. In agreement with previous observational studies, a series of simulations with modified ambient wind conditions reveal that the intense gusts (> 20 m s-1) only occur in a narrow window of ambient wind directions and if its speed is at least 16 m s-1. Smoothing the topography in the LES reduces the maximum wind speeds in the target region by 10–30 %. Overall, our semi-idealized LES in complex and steep terrain reveal the three-dimensional structure and the mechanism of the local windstorm. Moreover, they point to the importance of the local topography and its complex interplay with the three-dimensional and transient flow leading to the in-valley flow reversal and strong winds that characterize the Laseyer. The study further highlights the importance of the topographic details for the quantitatively correct simulation of atmospheric flows in complex terrain

The growth of entrepreneurial human capital : origins and development of skill variety

Plain English Summary Human capital is important for entrepreneurship. In particular, a varied skill set enables entrepreneurs to tackle the various tasks of starting a new firm. However, no one is born with such a skill set; it develops over time. In this study, we explore the origins of a varied skill set and its development. We find that skill variety in adulthood has its roots in a varied set of interests among teenagers, such as having many hobbies or finding different school subjects important. This growth in skill variety is driven by an entrepreneurial personality. For prospective entrepreneurs, our research suggests that investing in a varied skill set pays off. The implication for research is to look at the developmental process of how people become entrepreneurs. The most important conclusion for policymakers and educators is that educational support programs should center around encouraging especially adolescents and young adults to engage in varied activities and teach varied skills instead of focusing on a narrow curriculum. Given that recent research on entrepreneurial behavior and success has established skill variety as a central human capital factor, researchers, educators, and policymakers have turned their interest to a deeper understanding of the formation of skill variety. Based on human capital theory and the competence growth approach in developmental psychology (highlighting long-term, age-appropriate, and cumulative skill-growth processes), we hypothesize that a broad, early variety orientation in adolescence is a developmental precursor of such entrepreneurial human capital in adulthood. This was confirmed in an analysis of prospective longitudinal data via structural equation modeling and serial mediation tests. We also find that an entrepreneurial constellation of personality traits, but not entrepreneurial parents, predicts early variety orientation, skill variety, and entrepreneurial intentions. By shedding new light on the long-term formation of entrepreneurial human capital, the results suggest that establishing and benefiting from an early variety orientation is not only an important developmental mechanism in entrepreneurial careers but gives those with an entrepreneurial personality an early head start in their vocational entrepreneurial development. Implications for future research and practice are discussed.Peer reviewe