Housing Rent Dynamics and Rent Regulation in St. Petersburg (1880-1917)

This article studies the evolution of housing rents in St. Petersburg between 1880 and 1917 covering an eventful period of Russian and world history. We collect and digitize over 5,000 rental advertisements from historic newspapers, which we use together with geo-coded addresses and detailed structural characteristics to construct a quality-adjusted rent price index in continuous time. We provide the first pre-war and pre-Soviet index based on market data for any Russian housing market. In 1915, one of the world's earliest rent control and tenant protection policies was introduced as a response to soaring prices following the outbreak of World War I. We analyze the impact of this policy: while before the regulation rents were increasing at a similar rapid pace as other consumer prices, the policy reversed this trend. We find evidence for official compliance with the policy, document a rise in tenure duration and strongly increased rent affordability among workers after the introduction of the policy. We conclude that the immediate prelude to the October Revolution was indeed characterized by economic turmoil, but rent affordability and rising rents were no longer the prevailing problems.Series: Department of Economics Working Paper Serie

Superconducting gap of overdoped Tl2Ba2CuO6+d observed by Raman scattering

We report Raman scattering spectra for single crystals of overdoped Tl2Ba2CuO6+d (Tl-2201) at low temperatures. It was observed that the pair-breaking peaks in A1g and B1g spectra radically shift to lower energy with carrier doping. We interpret it as s-wave component mixing into d-wave, although the crystal structure is tetragonal. Since similar phenomena were observed also in YBa2Cu3Oy and Bi2Sr2CaCu2Oz, we conclude that s-wave mixing is a common property for overdoped high-Tc superconductors.Comment: 8 pages, 3 figures, proceedings of SNS200

Numerical modelling of mud volcanoes and their flows using constraints from the Gulf of Cadiz

It is estimated that the total number of submarine mud volcanoes is between 1000 and 100 000. Because many are associated with greenhouse gases, such as methane, it is argued that the global flux of these gases to the atmosphere from the world’s terrestrial and submarine mud volcanoes is highly significant. Clues to the processes forming submarine mud volcanoes can be found in variations to their height, shape, surface morphology, physical properties and internal structure. A model of isostatic compensation between the mud column and the sediment overlying the mud source is used to predict a depth to the mud reservoir beneath mud volcanoes. Once erupted, the general behaviour of an individual mud flow can be described and predicted using a viscous gravity-current model. The model shows that conical-shaped mud volcanoes comprise multiple, superimposed radial flows in which the thickness, eruption rate and speed of individual mud flows strongly depends on the viscosity, density and over-pressure of the erupted mud. Using these parameters, the model predicts the lowermost flows will be the oldest, thickest and have the greatest length of run-out while the uppermost flows will be the youngest, thinnest and shortest. This model is in contrast to more traditional models of stratiform mud volcano construction in which younger flows progressively bury older ones and travel furthest from the summit. Applying the model to the two mud volcanoes studied in the Gulf of Cadiz, quantitative estimates are derived for the depths to mud sources, exit and flow velocities, eruption duration and volume fluxes, flow thickness and conduit radii. For example, with an average kinematic viscosity of 1.5 m2 s?1 for the erupted mud, a density of 1.8×103 kg m?3 and a thickness for the youngest flows of about 0.5 m, the model predicts a lowermost flow thickness of 3.6 m, an average eruption duration of 7 h and a conduit radius of about 9 m. To construct a conical-shaped mud volcano of 260 m height, similar to those studied in the Gulf of Cadiz, is estimated to require a mud source at 4.6 km depth and a total of at least 100 individually erupted flows

Switching from visibility to invisibility via Fano resonances: theory and experiment

Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering functional metadevices, as well as scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for an uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of hight-index dielectric nanoparticles and the physics of cloaking.Comment: 8 pages, 4 figure

Quadruplets of exceptional points and bound states in the continuum in dielectric rings

In photonics, most systems are non-Hermitian due to radiation into open space and material losses. At the same time, non-Hermitianity defines a new physics, in particular, it gives rise to a new class of degenerations called exceptional points, where two or more resonances coalesce in both eigenvalues and eigenfunctions. The point of coalescence is a square root singularity of the energy spectrum as a function of interaction parameter. We investigated analytically and numerically the photonic properties of a narrow dielectric resonator with a rectangular cross section. It is shown that the exceptional points in such a resonator exist in pairs, and each of the points is adjacent in the parametric space to a bound state in the continuum, as a result of which quadruples of singular photonic states are formed. We also showed that the field distribution in the cross section of the ring is a characteristic fingerprint of both the bound state in the continuum and the exceptional point.Comment: 12 pages, 5 figure

Phase diagram for the transition from photonic crystals to dielectric metamaterials

Photonic crystals and metamaterials represent two seemingly different classes of artificial electromagnetic media but often they are composed of similar structural elements arranged in periodic lattices. The important question is how to distinguish these two types of periodic photonic structures when their parameters, such as dielectric permittivity and lattice spacing, vary continuously. Here, we discuss transitions between photonic crystals and all-dielectric metamaterials and introduce the concept of a phase diagram and an order parameter for such structured materials, based on the physics of Mie and Bragg resonances. We show that a periodic photonic structure transforms into a metamaterial when the Mie gap opens up below the lowest Bragg bandgap where the homogenization approach can be justified and the effective permeability becomes negative. Our theoretical approach is confirmed by detailed microwave experiments for a metacrystal composed of a square lattice of glass tubes filled with heated water. This analysis yields deep insight into the properties of periodic photonic structures, and it also provides a useful tool for designing different classes of electromagnetic materials in a broad range of parameters.Comment: 7 pages, 6 figure

Estimating the Impact of Restructuring on Electricity Generation Efficiency: The Case of the Indian Thermal Power Sector

We examine the impact of electricity sector restructuring on the operating efficiency of coal-fired power plants in India. Between 1995 and 2009, 85 percent of coal-based generation capacity owned by state governments was unbundled from vertically integrated State Electricity Boards into state generating companies. We find that generating units in states that unbundled before the Electricity Act of 2003 experienced reductions in forced outages of about 25% and improvements in availability of about 10%, with the largest results occurring 3-5 years after restructuring. We find no evidence of improvements in thermal efficiency at state-owned power plants due to reform.

Effects of carbon incorporation on doping state of YBa2Cu3Oy

Effects of carbon incorporation on the doping state of YBa2Cu3Oy (Y-123) were investigated. Quantitative carbon analysis revealed that carbon could be introduced into Y-123 from both the precursor and the sintering gas. Nearly carbon-free (< 200 ppm) samples were prepared from a vacuum-treated precursor by sintered at 900 &#730;C and cooling with 20 &#730;C /min in flowing oxygen gas. The lower Tc (= 88 K) and higher oxygen content (y = 6.98) strongly suggested the overdoping state, which was supported by the temperature dependence of resisitivity and thermoelectric power. The nuclear quadrapole resonance spectra and the Raman scattering spectra indicated that there was almost no oxygen defect in the Cu-O chain in these samples. On the other hand, in the same cooling condition, the samples sintered in air stayed at optimal doping level with Tc = 93 K, and the intentionally carbon-doped sample was in the underdoping state. It is revealed that about 60% of incorporated carbon was substituted for Cu at the chain site in the form of CO32+, and the rest remains at the grain boundary as carbonate impurities. Such incorporation affected the oxygen absorption process in Y-123. It turned out that the oxygen content in Y-123 cannot be controlled only by the annealing temperature and the oxygen partial pressure but also by the incorporated carbon concentration.Comment: 16pages, 9figure