A Tax-Based Test of the Dividend Signaling Hypothesis

We propose and implement a new test of the dividend signaling hypothesis that is designed to discriminate between dividend signaling and other theories that would account for the apparent existence of a dividend preference. Our test refines the use of data on stock price responses to dividend announcements. In particular, we study the effect of dividend taxation on the bang-for-the-buck, which we define as the share price response per dollar of dividends. Most dividend signaling models imply that an increase in dividend taxation should increase the bang-for-the-buck. In contrast, other dividend preference theories imply that an increase in dividend taxation should decrease the bang-for-the-buck. Since there have recently been considerable variation in the tax treatment of dividends, we are able to study dividend announcement effects under different tax regimes. Our central finding is that there is a strong positive relationship between dividend tax rates and the bang-for-the-buck. This result supports the dividend signaling hypothesis, and is consistent with alternatives. The paper also provides corroborating evidence based on the relationship between the bang-for-the-buck and bond ratings.

The instanton liquid and the axion

Description of the low energy regime of QCD in terms of a self-interacting ensemble of instantons, the instanton liquid, at zero and finite temperature. The application addressed in this thesis is a precise determination of the axion mass, at all temperatures, within this framework.The ultimate goal of this thesis is to improve our understanding of the cosmology of axions. Axions couple to QCD instantons and these non-perturbative effects are modeled within the framework of the interacting instanton liquid model (IILM). The thesis describes the significant advances made within the IILM in order to study the quark-gluon plasma in realistic parameter regimes. In particular, a determination of the temperature-dependent axion mass in the IILM lays the foundation for a critical reevaluation and update of present cosmological axion constraints. We develop grand canonical Monte Carlo routines to study topological fluctuations in the quark-gluon plasma. The model is calibrated against the topological susceptibility at zero temperature, in the chiral regime of physical quark masses. A numerical framework to derive interactions among the pseudo-particles is developed that is in principle exact, and is used to cure a pathology in the presently available finite temperature interactions. The IILM reduces field theory to a molecular dynamics description, and we show that, quite generically, the dynamics for non-trivial backgrounds in the presence of light quarks is reminiscent of a strongly associating fluid. To deal with the well-known difficulty in simulating ionic fluids, we develop advanced algorithms based on Biased Monte Carlo techniques. We study the IILM at finite temperature in the quenched and unquenched sector, with due diligence to a consistent thermodynamic limit. Of particular interest is chiral symmetry breaking and the temperature dependence of the topological susceptibility, and we study in detail the effects of instanton--anti-instanton pairs. Our determination of the topological susceptibility provides, for the first time, a well-motivated axion mass for all temperatures. The misalignment mechanism for axion production is studied in detail, solving the evolution equations exactly in a radiation dominated FRW universe with the full temperature dependence of the effective degrees of freedom taken into account. Improved constraints in the classic and anthropic axion window are derived. We generalise the latter to large angle fine-tuning by including in the isocurvature contribution to the cosmic microwave background radiation the full anharmonic axion potential effects. Finally, we reexamine bounds from axion string radiation in the thermal scenario to complete a comprehensive update of all cosmological axion constraints

Arbeitszeiterfassung : Rechtslage und Praxis der Arbeitszeiterfassung in Deutschland, Frankreich, Italien und Österreich

In der Schweiz wird verschiedentlich der Wunsch nach einer Lockerung der arbeitsgesetzlichen Pflicht zur Aufzeichnung der Arbeitszeit geäussert. Das Staatssekretariat für Wirtschaft SECO hat das Zentrum für Sozialrecht der Zürcher Hochschule für angewandte Wissenschaften (ZHAW) in diesem Zusammenhang mit einem Gutachten beauftragt. Es ging darum, die Rechtslage wie auch die Praxis der Arbeitsinspektorate in Deutschland, Frankreich, Italien und Österreich zu erheben. Obwohl diese vier Staaten dem europäischen Recht unterstehen und (wie die Schweiz) das ILO-Abkommen Nr. 81 über die Arbeitsinspektion ratifiziert haben, ergeben sich gemäss schriftlichen und telefonischen Befragungen der relevanten Akteure in den jeweiligen Ländern gewisse Unterschiede im innerstaatlichen Recht und in der praktischen Umsetzung

Elaboration, caractérisation et optimisation de diodes électroluminescentes à base de polymères conjugués

Cette thèse concerne l'étude des diodes électroluminescentes à base de matériaux semiconducteurs polymères (PLEDs). Cette technologie est prometteuse pour la fabrication d'écran plats à bas coûts. Plusieurs polymères dérivés du poly(phénylènevinylène) (PPVs) comme le MEH-PPV et le BDMO-PPV ont été étudiés. Ces travaux se divisent en trois parties distinctes. Tout d'abord, des aspects technologiques liés à la fabrication des composants sont abordés : comme le choix des matériaux d'électrodes, ou encore l'étude de l'effet de la rugosité de l'ITO sur les performances des diodes électroluminescentes. Cette rugosité s'avère être un paramètre critique sur les durées de vie des dispositifs. L'analyse des mécanismes de transfert de charges au sein des diodes est ensuite abordée par l'étude de l'effet de la température sur les caractéristiques courant-tension-luminance des dispositifs mais aussi sur l'allure de leur spectre d'électroluminescence. Au sein des PPVs, le porteur majoritaire s'avère être le trou. Par conséquent, l'optimisation des performances des PLEDs est montrée possible par l'ajout d'une couche additionnelle à base de petites molécules évaporées entre le polymère émissif et la cathode afin de confiner ces porteurs à améliorer la balance des charges.This thesis deals with the study of polymer light-emitting diodes (PLEDs) which present many attractive properties to develop a new display technology. Poly(phenylenevinylene) derivatives (PPVs) such as MEH-PPV and BDMO-PPV have been studied. Three parts may be considered in this work. First, technological aspects related to device fabrication are studied, such as the electrode material choice or the effect of the ITO roughness on the performances of PLEDs. This roughness was found to be a critical parameter in terms of device lifetime. Then, charge transfer mechanisms through the polymer are evaluated by the study of the temperature dependence of current-voltage-luminance curves as well as of the temperature dependence of the electroluminescence spectra. Holes are found to be the majority charge carriers in PPVs. As a consequence, in the last part, device optimisation is made possible by addition of a specific vacuum evaporated molecular layer between the emissive polymer and the cathode to improve the charge balance

New Detection Thresholds and Stop Rules for CUSUM Online Detection.

International audienceWe address the problem of online detection of a change point via the online version of the CUSUM method. Change-point detection is based on the choice of a statistics and the threshold it must reach to report a change. CUSUM statistics is based on a sequential test of the likelihood ratio, which can be replaced by a score function in the non-parametric case and the classical method for selecting the detection threshold is based on Wald inequalities [Wald, A., D. J. (1945)].In our work, we propose an empirical method for the selection of the detection threshold. We also suggest replacing the constant threshold with an instantaneous time-dependent threshold. In order to control the instantaneous false alarm rate (IFAR), the mean time between false alarms (MTBFA) and the average detection delay (ADD), we propose new procedures by correcting the stop rule usually used in the CUSUM approach.In order to evaluate and compare new different methods for selecting detection threshold and the new stop rules, we perform simulations to evaluate detection parameters in each case

Enumeration of Nonsingular Buekenhout Unitals

The only known enumeration of Buekenhout unitals occurs in the Desarguesian plane $PG(2,q^2)$.  In this paper we develop general techniques for enumerating the nonsingular Buekenhoutunitals embedded in any two-dimensional translation plane, and apply these techniques to obtain such an enumeration in the regular nearfield planes, the odd-order Hall planes, and the flag-transitive affine planes.  We also provide some computer data for small-order André planes of index two and give partial results toward an enumeration in this case

Axion Cosmology Revisited

The misalignment mechanism for axion production depends on the temperature-dependent axion mass. The latter has recently been determined within the interacting instanton liquid model (IILM), and provides for the first time a well-motivated axion mass for all temperatures. We reexamine the constraints placed on the axion parameter space in the light of this new mass function. We find an accurate and updated constraint f_a \le 2.8(\pm2)\times 10^{11}\units{GeV} or m_a \ge 21(\pm2) \units{\mu eV} from the misalignment mechanism in the classic axion window (thermal scenario). However, this is superseded by axion string radiation which leads to f_a \lesssim 3.2^{+4}_{-2} \times 10^{10} \units{GeV} or m_a \gtrsim 0.20 ^{+0.2}_{-0.1} \units{meV}. In this analysis, we take care to precisely compute the effective degrees of freedom and, to fill a gap in the literature, we present accurate fitting formulas. We solve the evolution equations exactly, and find that analytic results used to date generally underestimate the full numerical solution by a factor 2-3. In the inflationary scenario, axions induce isocurvature fluctuations and constrain the allowed inflationary scale $H_I$. Taking anharmonic effects into account, we show that these bounds are actually weaker than previously computed. Considering the fine-tuning issue of the misalignment angle in the whole of the anthropic window, we derive new bounds which open up the inflationary window near $\theta_a \to \pi$. In particular, we find that inflationary dark matter axions can have masses as high as 0.01--1\units{meV}, covering the whole thermal axion range, with values of $H_I$ up to $10^9$GeV. Quantum fluctuations during inflation exclude dominant dark matter axions with masses above $m_a\lesssim 1$meV.Comment: 42 pages, 12 figures, version as accepted by Phys.Rev.

Temperature Dependence of Exciton Diffusion in Conjugated Polymers

The temperature dependence of the exciton dynamics in a conjugated polymer is studied using time-resolved spectroscopy. Photoluminescence decays were measured in heterostructured samples containing a sharp polymer-fullerene interface, which acts as an exciton quenching wall. Using a 1D diffusion model, the exciton diffusion length and diffusion coefficient were extracted in the temperature range of 4-293 K. The exciton dynamics reveal two temperature regimes: in the range of 4-150 K, the exciton diffusion length (coefficient) of ~3 nm (~1.5 × 10-4 cm2/s) is nearly temperature independent. Increasing the temperature up to 293 K leads to a gradual growth up to 4.5 nm (~3.2 × 10-4 cm2/s). This demonstrates that exciton diffusion in conjugated polymers is governed by two processes: an initial downhill migration toward lower energy states in the inhomogenously broadened density of states, followed by temperature activated hopping. The latter process is switched off below 150 K.

National Partisanship and State Policy Diffusion: The Impact of Polarized Parties on State Policy Decisions

This project is an examination of patterns of state policy adoption, and provides a new theory for policy diffusion research. While traditional policy diffusion research focuses on geographic proximity as the main mechanism for policy adoption, I argue that states are more likely to rely on partisan proximity and adopt policy from partisan neighbors. This is, primarily, a result of heightened polarization nationally. In the absence of national policymaking, states will feel both more pressure to create more policy as well as leeway to enact more partisan policies. In order to test this theory, I look at three cases: same-sex marriage, right-to-work, and state lottery adoption. I utilize interviews with state lawmakers and interest group staff as well as quantitative methods to show the relationship between partisanship and policy diffusion. Overall, this work adds an important element to a vast and well-established literature and provides a new way of understanding the policy creation in the American states