Transition to What?

Summaries This article examines the development of monetary policy in Russia since prices were liberalised in 1992. It traces events from the monetary overhang which preceded that step, through sharp inflation and the monetary contraction with which stability was restored, to the present crisis of illiquidity and demonetisation. The article argues that, far from easing the way to flexible, market?based policies, this chain of events has left policymakers as severely boxed in as at the start. While any reform strategy was fraught with danger, it would have been better to take a less cavalier attitude to prices and concentrate from the beginning on building the financial and legal institutions required for macro?economic policy to work

Revised structural phase diagram of (Ba0.7Ca0.3TiO3)-(BaZr0.2Ti0.8O3)

The temperature-composition phase diagram of barium calcium titanate zirconate (x(Ba0.7Ca0.3TiO3)(1-x)(BaZr0.2Ti0.8O3); BCTZ) has been reinvestigated using high-resolution synchrotron x-ray powder diffraction. Contrary to previous reports of an unusual rhombohedral-tetragonal phase transition in this system, we have observed an intermediate orthorhombic phase, isostructural to that present in the parent phase, BaTiO3, and we identify the previously assigned T-R transition as a T-O transition. We also observe the O-R transition coalescing with the previously observed triple point, forming a phase convergence region. The implication of the orthorhombic phase in reconciling the exceptional piezoelectric properties with the surrounding phase diagram is discussed

Numerical investigations on the transient aerodynamic performance characterization of a multibladed vertical axis wind turbine.

The use of vertical axis wind turbines (VAWTs) in urban environments is on the rise due to their relatively smaller size, simpler design, lower manufacturing and maintenance costs, and above all, due to their omnidirectionality. The multibladed drag-based VAWT has been identified as a design configuration with superior aerodynamic performance. Numerous studies have been carried out in order to better understand the complex aerodynamic performance of multibladed VAWTs employing steady-state or quasi-steady numerical methods. The transient aerodynamics associated with a multibladed VAWT, especially the time–history of the power coefficient of each blade, has not been reported in the published literature. This information is important for the identification of individual blade’s orientation when producing negative torque. The current study aims to bridge this gap in the literature through real-time tracking of the rotor blade's aerodynamic performance characteristics during one complete revolution. Numerical investigations were carried out using advanced computational fluid dynamics (CFD)-based techniques for a tip speed ratio of 0 to 1. The results indicate that transient aerodynamic characterization is 13% more accurate in predicting the power generation from the VAWT. While steady-state performance characterization indicates a negative power coefficient (Cp) at λ = 0.65, transient analysis suggests that this happens at λ = 0.75

Hydrology of the Ferron Sandstone Aquifer and Effects of Proposed Surface-Coal Mining in Castle Valley, Utah

Coal in the Ferron Sandstone Member of the Mancos Shale of Cretaceous age has traditionally been mined by underground techniques in the Emery Coal Field in the southern end of Castle Valley in east-central Utah. However, approximately 99 million tons are recoverable by surface mining. Ground water in the Ferron is the sole source of supply for the town of Emery, but the aquifer is essentially untapped outside the Emery area. The Ferron Sandstone Member crops out along the eastern edge of Castle Valley and generally dips 2 to 10 to the northwest beneath the surface. Sandstones in the Ferron are enclosed between relatively impermeable shale in the Tununk and Blue Gate Members of the Mancos Shale. Along the outcrop, the Ferron ranges in thickness from about 80 feet in the northern part of Castle Valley to 850 feet in the southern part. The Ferron also generally thickens in the subsurface downdip from the outcrop. Records from wells and test holes indicate that the full thickness of the Ferron is saturated with water in most areas downdip from the outcrop area. Tests in the Emery area indicate that transmissivity of the Ferron sandstone aquifer ranges from about 200 to 700 feet squared per day where the Ferron is fully saturated. Aquifer transmissivity is greatest near the Paradise Valley-- Joes Valley fault system where permeability has been increased by fracturing. Storage coefficient ranges from about 10^-6 to 10^-3 where the Ferron sandstone aquifer is confined and probably averages 5 x 10^-2 where in is unconfined

Localized Basis for Effective Lattice Hamiltonians: Lattice Wannier Functions

A systematic method is presented for constructing effective Hamiltonians for general phonon-related structural transitions. The key feature is the application of group theoretical methods to identify the subspace in which the effective Hamiltonian acts and construct for it localized basis vectors, which are the analogue of electronic Wannier functions. The results of the symmetry analysis for the perovskite, rocksalt, fluorite and A15 structures and the forms of effective Hamiltonians for the ferroelectric transition in $PbTiO_3$ and $BaTiO_3$, the oxygen-octahedron rotation transition in $SrTiO_3$, the Jahn-Teller instability in $La_{1-x}(Ca,Sr,Ba)_xMnO_3$ and the antiferroelectric transition in $PbZrO_3$ are discussed. For the oxygen- octahedron rotation transition in $SrTiO_3$, this method provides an alternative to the rotational variable approach which is well behaved throughout the Brillouin zone. The parameters appearing in the Wannier basis vectors and in the effective Hamiltonian, given by the corresponding invariant energy expansion, can be obtained for individual materials using first- principles density-functional-theory total energy and linear response techniques, or any technique that can reliably calculate force constants and distortion energies. A practical approach to the determination of these parameters is presented and the application to ferroelectric $PbTiO_3$ discussed.Comment: extensive revisions in presentation, 32 pages, Revtex, 7 Postscript figure

The polarizability model for ferroelectricity in perovskite oxides

This article reviews the polarizability model and its applications to ferroelectric perovskite oxides. The motivation for the introduction of the model is discussed and nonlinear oxygen ion polarizability effects and their lattice dynamical implementation outlined. While a large part of this work is dedicated to results obtained within the self-consistent-phonon approximation (SPA), also nonlinear solutions of the model are handled which are of interest to the physics of relaxor ferroelectrics, domain wall motions, incommensurate phase transitions. The main emphasis is to compare the results of the model with experimental data and to predict novel phenomena.Comment: 55 pages, 35 figure

Importance of factors determining the effective lifetime of a mass, long-lasting, insecticidal net distribution: a sensitivity analysis

ABSTRACT: BACKGROUND: Long-lasting insecticidal nets (LLINs) reduce malaria transmission by protecting individuals from infectious bites, and by reducing mosquito survival. In recent years, millions of LLINs have been distributed across sub-Saharan Africa (SSA). Over time, LLINs decay physically and chemically and are destroyed, making repeated interventions necessary to prevent a resurgence of malaria. Because its effects on transmission are important (more so than the effects of individual protection), estimates of the lifetime of mass distribution rounds should be based on the effective length of epidemiological protection. METHODS: Simulation models, parameterised using available field data, were used to analyse how the distribution's effective lifetime depends on the transmission setting and on LLIN characteristics. Factors considered were the pre-intervention transmission level, initial coverage, net attrition, and both physical and chemical decay. An ensemble of 14 stochastic individual-based model variants for malaria in humans was used, combined with a deterministic model for malaria in mosquitoes. RESULTS: The effective lifetime was most sensitive to the pre-intervention transmission level, with a lifetime of almost 10 years at an entomological inoculation rate of two infectious bites per adult per annum (ibpapa), but of little more than 2 years at 256 ibpapa. The LLIN attrition rate and the insecticide decay rate were the next most important parameters. The lifetime was surprisingly insensitive to physical decay parameters, but this could change as physical integrity gains importance with the emergence and spread of pyrethroid resistance. CONCLUSIONS: The strong dependency of the effective lifetime on the pre-intervention transmission level indicated that the required distribution frequency may vary more with the local entomological situation than with LLIN quality or the characteristics of the distribution system. This highlights the need for malaria monitoring both before and during intervention programmes, particularly since there are likely to be strong variations between years and over short distances. The majority of SSA's population falls into exposure categories where the lifetime is relatively long, but because exposure estimates are highly uncertain, it is necessary to consider subsequent interventions before the end of the expected effective lifetime based on an imprecise transmission measur

The Effects of Age, Exposure History and Malaria Infection on the Susceptibility of Anopheles Mosquitoes to Low Concentrations of Pyrethroid

Chemical insecticides are critical components of malaria control programs. Their ability to eliminate huge numbers of mosquitoes allows them to swiftly interrupt disease transmission, but that lethality also imposes immense selection for insecticide resistance. Targeting control at the small portion of the mosquito population actually responsible for transmitting malaria parasites to humans would reduce selection for resistance, yet maintain effective malaria control. Here, we ask whether simply lowering the concentration of the active ingredient in insecticide formulations could preferentially kill mosquitoes infected with malaria and/or those that are potentially infectious, namely, old mosquitoes. Using modified WHO resistance-monitoring assays, we exposed uninfected Anopheles stephensi females to low concentrations of the pyrethroid permethrin at days 4, 8, 12, and 16 days post-emergence and monitored survival for at least 30 days to evaluate the immediate and long-term effects of repeated exposure as mosquitoes aged. We also exposed Plasmodium chabaudi- and P. yoelii-infected An. stephensi females. Permethrin exposure did not consistently increase mosquito susceptibility to subsequent insecticide exposure, though older mosquitoes were more susceptible. A blood meal slightly improved survival after insecticide exposure; malaria infection did not detectably increase insecticide susceptibility. Exposure to low concentrations over successive feeding cycles substantially altered cohort age-structure. Our data suggest the possibility that, where high insecticide coverage can be achieved, low concentration formulations have the capacity to reduce disease transmission without the massive selection for resistance imposed by current practice

The Price of Failure:

Summaries This article examines the development of monetary policy in Russia since prices were liberalised in 1992. It traces events from the monetary overhang which preceded that step, through sharp inflation and the monetary contraction with which stability was restored, to the present crisis of illiquidity and demonetisation. The article argues that, far from easing the way to flexible, market?based policies, this chain of events has left policymakers as severely boxed in as at the start. While any reform strategy was fraught with danger, it would have been better to take a less cavalier attitude to prices and concentrate from the beginning on building the financial and legal institutions required for macro?economic policy to work