Quantum Tunneling and Phase Transitions in Spin Systems with an Applied Magnetic Field

Transitions from classical to quantum behaviour in a spin system with two degenerate ground states separated by twin energy barriers which are asymmetric due to an applied magnetic field are investigated. It is shown that these transitions can be interpreted as first- or second-order phase transitions depending on the anisotropy and magnetic parameters defining the system in an effective Lagrangian description.Comment: 18 pages, 7 figure

The Rise and Fall of Social Housing? Housing Decommodification in Long-Run Perspective

The comparative study of housing decommodification lags behind classical welfare state research, while housing research itself is rich in homeownership studies but lacks comparative accounts of private and social rentals due to missing comparative data. Building on existing works and various primary sources, this study presents a new collection of up to forty-eight countries’ social housing shares in stock and new construction since the first housing laws around 1900. The interpolated benchmark time series generally describe the rise and fall of social housing across a residual, a socialist, and a Northern-European housing group. The decline was steeper than for the classical welfare state, but the degree of erosion was surprisingly small in some countries where public housing associations remained resilient. Within the broader housing welfare state, social housing correlates positively with rent regulation and allowances, but negatively with homeownership subsidies and liberal mortgage regulation. A multivariate analysis shows that social housing is rather explained by housing shortages and complementarities with rental and welfare policies than by typical welfare state theories (GDP, political parties). Generally, the paper shows that conventional housing typologies are difficult to defend over time and argues more generally for including housing decommodification in welfare state research.Die vergleichende Forschung zur Dekommodifizierung des Gutes Wohnen ist bisher von der klassischen Wohlfahrtsstaatsforschung vernachlässigt worden. Die Wohnungsforschung selbst ist wiederum reich an Studien zum Wohneigentum, aber vergleichende Darstellungen zu privaten und sozialen Mietwohnungen sind aufgrund fehlender komparativer Daten wenig erforscht. Aufbauend auf bestehenden Arbeiten und verschiedenen Primärquellen stellt diese Studie daher zunächst eine neue Datensammlung von bis zu 48 Ländern vor, die den Anteil der Sozialwohnungen an den Beständen und Neubauten seit den ersten Wohnungsbaugesetzen um 1900 erfasst. Die interpolierten Benchmark-Zeitreihen beschreiben im Allgemeinen den Aufstieg und Fall des sozialen Wohnungsbaus in einem residualen, sozialistischen und einem nordeuropäischen Wohnungsregime. Der Rückgang war steiler als beim klassischen Wohlfahrtsstaat, aber überraschend resilient in Ländern mit öffentlichen Wohnungsbaugesellschaften. Innerhalb des umfassenderen Wohnungswohlfahrtsstaates korreliert der soziale Wohnungsbau positiv mit der Regulierung von Mieten und Wohngeldzahlungen, aber negativ mit Wohneigentumssubventionen und liberalen Hypothekenregelungen. Eine multivariate Analyse zeigt, dass der soziale Wohnungsbau eher durch Wohnungsknappheit und funktionale Komplementarität mit Miet- und Sozialpolitik als mit typischen wohlfahrtsstaatlichen Faktoren (BIP, politische Parteien) erklärt wird. Generell zeigt der Beitrag, dass herkömmliche Wohnungstypologien im Laufe der Zeit nur schwer zu verteidigen sind, und plädiert dafür, die Dekommodifizierung von Wohnraum stärker in die Wohlfahrtsstaatsforschung einzubeziehen.Contents 1 Introduction 2 Social housing: What it is and how to measure it? 3 Descriptive results 4 Bivariate findings: Social housing and the broader housing welfare state 5 Multivariate: The determinants of social housing provision 6 Conclusion Appendix Reference

Fine Structure of the 1s3p ^3P_J Level in Atomic ^4He: Theory and Experiment

We report on a theoretical calculation and a new experimental determination of the 1s3p ^3P_J fine structure intervals in atomic ^4He. The values from the theoretical calculation of 8113.730(6) MHz and 658.801(6) MHz for the nu_{01} and nu_{12} intervals, respectively, disagree significantly with previous experimental results. However, the new laser spectroscopic measurement reported here yields values of 8113.714(28) MHz and 658.810(18) MHz for these intervals. These results show an excellent agreement with the theoretical values and resolve the apparent discrepancy between theory and experiment.Comment: 9 pages, 3 figure

Bonding machine for forming a solar array strip

A machine is described for attaching solar cells to a flexable substrate on which printed circuitry has been deposited. The strip is fed through: (1) a station in which solar cells are elevated into engagement with solder pads for the printed circuitry and thereafter heated by an infrared lamp; (2) a station at which flux and solder residue is removed; (3) a station at which electrical performance of the soldered cells is determined; (4) a station at which an encapsulating resin is deposited on the cells; (5) a station at which the encapsulated solar cells are examined for electrical performance; and (6) a final station at which the resulting array is wound on a takeup drum

The degradation of MgB2 under ambient environment

The superconductivities of samples prepared by several procedures were found to degrade under ambient environment. The degradation mechanism was studied by measuring the change of surface chemical composition of dense MgB2 pellets (prepared by hot isostatic pressure, HIPed) under atmospheric exposure using X-ray Photoelectron Spectroscopy (XPS). Results showed that samples with poor connectivity between grains and with smaller grain sizes degrade with time when exposed to ambient conditions. In these samples, the Tc did not change with time, but the superconducting transition became broader and the Meissner fraction decreased. In contrast, our well-sintered and the HIPed samples remained stable for several months under ambient condition. The degradation was found to be related to surface decomposition as observed by XPS. We observed the formation of oxidized Mg, primarily in the form of a Mg hydroxide, the increase of C and O contents, and the reduction of B concentration in the surface layer of MgB2 samples.Comment: 15 pages, 3 figure

Concurrent TNFRSF1A R92Q and pyrin E230K mutations in a child with multiple sclerosis

We report a 16-year-old female patient with a severe course of multiple sclerosis and concomitant symptoms suggestive of a hereditary autoinflammatory disease. Genetic analyses revealed that she inherited a TNFRSF1A R92Q mutation from her mother and a pyrin E230K mutation from her father. To our knowledge, this is the first report of a patient with severe childhood multiple sclerosis and mutations in two genes which predispose to hereditary autoinflammatory disorders. We speculate that these mutations contribute to early multiple sclerosis manifestation and enhance the inflammatory damage inflicted by the autoimmune response

Decay Process for Three - Species Reaction - Diffusion System

We propose the deterministic rate equation of three-species in the reaction - diffusion system. For this case, our purpose is to carry out the decay process in our three-species reaction-diffusion model of the form $A+B+C\to D$. The particle density and the global reaction rate are also shown analytically and numerically on a two-dimensional square lattice with the periodic boundary conditions. Especially, the crossover of the global reaction rate is discussed in both early-time and long-time regimes.Comment: 6 pages, 3 figures, Late

Gluon saturation effects on the color singlet J/Psi production in high energy dA and AA collisions

We derive the formulae for the cross section of J/Psi production in high energy pA and AA collisions taking into account the gluon saturation/color glass condensate effects. We then perform the numerical calculations of the corresponding nuclear modification factors and find a good agreement between our calculations and the experimental data on J/Psi production in dA collisions. We also observe that cold nuclear modification effects alone cannot describe the data on J/Psi production in AA collisions. Additional final state suppression (at RHIC) and enhancement (at LHC) mechanisms are required to explain the experimental observations.Comment: 11 pages, 6 figure