Binding of Polarons and Atoms at Threshold

If the polaron coupling constant $\alpha$ is large enough, bipolarons or multi-polarons will form. When passing through the critical $\alpha_c$ from above, does the radius of the system simply get arbitrarily large or does it reach a maximum and then explodes? We prove that it is always the latter. We also prove the analogous statement for the Pekar-Tomasevich (PT) approximation to the energy, in which case there is a solution to the PT equation at $\alpha_c$. Similarly, we show that the same phenomenon occurs for atoms, e.g., helium, at the critical value of the nuclear charge. Our proofs rely only on energy estimates, not on a detailed analysis of the Schr\"odinger equation, and are very general. They use the fact that the Coulomb repulsion decays like $1/r$, while `uncertainty principle' localization energies decay more rapidly, as $1/r^2$.Comment: 19 page

Search for an annual modulation of dark-matter signals with a germanium spectrometer at the Sierra Grande Laboratory

Data collected during three years with a germanium spectrometer at the Sierra Grande underground laboratory have been analyzed for distinctive features of annual modulation of the signal induced by WIMP dark matter candidates. The main motivation for this analysis was the recent suggestion by the DAMA/NaI Collaboration that a yearly modulation signal could not be rejected at the 90% confidence level when analyzing data obtained with a high-mass low-background scintillator detector. We performed two different analyses of the data: First, the statistical distribution of modulation-significance variables (expected from an experiment running under the conditions of Sierra Grande) was compared with the same variables obtained from the data. Second, the data were analyzed in energy bins as an independent check of the first result and to allow for the possibility of a crossover in the expected signal. In both cases no statistically significant deviation from the null result was found, which could support the hypothesis that the data contain a modulated component. A plot is also presented to enable the comparison of these results to those of the DAMA collaboration.Comment: New version accepted by Astroparticle Physics. Changes suggested by the referee about the theoretical prediction of rates are included. Conclusions remain unaffected. 14 pages, LaTeX, 7 figures. Uses epsfig macr

Attitudes toward westbound refugees in the East German press

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67107/2/10.1177_002200277001400303.pd

Psychology and aggression

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68264/2/10.1177_002200275900300301.pd

Dark Matter Search with CUORE-0 and CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale experiment made of TeO2 bolometers that will probe the neutrinoless double beta decay of 130Te. Excellent energy resolution, low threshold and low background make CUORE sensitive to nuclear recoils, allowing a search for dark matter interactions. With a total mass of 741 kg of TeO2, CUORE can search for an annual modulation of the counting rate at low energies. We present data obtained with CUORE-like detectors and the prospects for a dark matter search in CUORE-0, a 40-kg prototype, and CUORE

Partial discharge within a spherical cavity in a dielectric material as a function of cavity size and material temperature

For high-voltage components, the measurement of partial discharge (PD) is a useful tool for performance assessment of electrical insulation. In this study, experimental measurements of PD activity for different spherical cavity sizes and material temperatures have been performed. A simulation model representing PD behaviour within spherical cavities in homogeneous dielectric materials has also been developed. The model has been used to study the influence of cavity size and material temperature on PD activity. Comparison of measurement and simulation results has been undertaken. The model uses a finite element analysis (FEA) method along with MATLAB code. It has been found that certain parameters in the model are both cavity size and temperature dependent. Thus, critical parameters influencing PD behaviour for different cavity sizes within the material and material temperatures can be identified; these are the charge decay time constant, cavity surface conductivity, electron generation rate (EGR), PD inception and extinction fields and the cavity temperature decay time constant

Comparison between three-capacitance, analytical-based and finite element analysis partial discharge models in condition monitoring

An important and essential diagnostic tool for insulation systems in condition monitoring is partial discharge (PD) measurement. Through PD measurement, the results may be used for insulation condition assessment. However, the modelling of PD is important because it is helpful in attaining a better understanding of PD phenomenon. The physical mechanisms and critical parameters influencing PD events under various conditions of defects and stresses can be identified. The relationship between the insulation design parameters, test conditions and defect characteristics with PD activities can also be developed. There have been many researches that reported on simulation of PD events in a void in insulation material. PD models can be categorized in three models, they are the induced charge concept model, three-capacitance model and the finite element method models. Each model has its own strengths and limitations in certain aspects. Therefore, in this paper, comparative studies and simulations for various PD models that have been developed to date are reported and discussed. The disadvantages and advantages of every model are presented in details. The results from the simulation using those models were compared with the measurement data to observe their performance in terms of physical parameters values. From comparative studies between each model, the most suitable PD model can be chosen to simulate PD events depending on the requirement selected by the users