1,350 research outputs found

    Effects of California migration

    Get PDF
    California ; Emigration and immigration ; West (U.S.) ; Federal Reserve District, 12th

    Housing price cycles and prepayment rates of U.S. mortgage pools.

    Get PDF
    Empirical mortgage prepayment models generally have trouble explaining differences in mortgage prepayment speeds among pools with similar interest rates on the underlying mortgages. In this paper, we model some of the sources of termination heterogeneity across mortgage pools, particularly the role of regional variations in housing prices in generating atypical prepayment speeds. Using a sample of Freddie Mac mortgage pools from 1991-1998, we find evidence that differences in house price dynamics across regions are an important source of between-pool heterogeneity. This finding is then shown to be robust to alternative ways of parameterizing pool heterogeneity in mortgage termination models.Real property ; Mortgages

    A Time Domain Approach to Power Integrity for Printed Circuit Boards

    Get PDF
    Power integrity is becoming increasingly relevant due to increases in device functionality and switching speeds along with reduced operating voltage. Large current spikes at the device terminals result in electromagnetic disturbances which can establish resonant patterns affecting the operation of the whole system. These effects have been examined using a finite difference time domain approach to solve Maxwell's equations for the PCB power and ground plane configuration. The simulation domain is terminated with a uniaxial perfectly matched layer to prevent unwanted reflections. This approach calculates the field values as a function of position and time and allows the evolution of the field to be visualized. The propagation of a pulse over the ground plane was observed demonstrating the establishment of a complex interference pattern between source and reflected wave fronts and then between multiply reflected wave fronts. This interference which affects the whole ground plane area could adversely affect the operation of any device on the board. These resonant waves persist for a significant time after the initial pulse. Examining the FFT of the ground plane electric field response showed numerous resonant peaks at frequencies consistent with the expected values assuming the PCB can be modelled as a resonant cavity with two electric and four magnetic field boundaries.Comment: Presented at The University of Bolton Research and Innovation Conference, Bolton, UK. 16th September, 201

    Thermally activated conductance of a silicon inversion layer by electrons excited above the mobility edge

    Get PDF
    The thermally activated conductivity sigma of an n-type inversion layer on a (100) oriented silicon surface and its derivative d sigma /dT were measured in the temperature range 1.4K-4.2K. Above T approximately=2.5K both the temperature dependence of (T/ sigma ) (d sigma /dT) and the relation between this quantity and sigma cannot be reconciled with a universal pre-exponential factor, i.e. the minimum metallic conductivity, but are shown to be satisfactorily described by a prefactor which is proportional to the temperature. The experimental results presented are consistent with activation of the number of mobile electrons above a mobility edge in the lowest sub-band, and indicate a mobility which is independent of both temperature and electron density

    Association of circulating levels of MMP-8 with mortality from respiratory disease in patients with rheumatoid arthritis.

    Get PDF
    Matrix metalloproteinases (MMPs) are implicated in the destruction of the joint and have been shown to be strongly associated with inflammation in rheumatoid arthritis (RA). Circulating MMPs have also been associated with cardiovascular disease in the general population, and are predictive of cardiovascular mortality. The purpose of the present study was to determine whether circulating levels of MMPs are predictive of mortality in RA

    Characteristics and carbon stable isotopes of fluids in the Southern Kerala granulites and their bearing on the source of CO2

    Get PDF
    Carbon dioxide-rich inclusions commonly occur in the banded charnockites and khondalites of southern Kerala as well as in the incipient charnockites formed by desiccation of gneisses along oriented zones. The combined high density fluid inclusion isochores and the range of thermometric estimates from mineral assemblages indicate entrapment pressures in the range of 5.4 to 6.1 Kbar. The CO2 equation of state barometry closely compares with the 5 plus or minus 1 Kbar estimate from mineral phases for the region. The isochores for the high density fluid inclusions in all the three rock types pass through the P-T domain recorded by phase equilibria, implying that carbon dioxide was the dominating ambient fluid species during peak metamorphic conditions. In order to constrain the source of fluids and to evaluate the mechanism of desiccation, researchers undertook detailed investigations of the carbon stable isotope composition of entrapped fluids. Researchers report here the results of preliminary studies in some of the classic localities in southern Kerala namely, Ponmudi, Kottavattom, Manali and Kadakamon

    Stable isotope studies on granulites from the high grade terrain of Southern India

    Get PDF
    Fluid inclusion and petrologic characteristics of South India granulites and their bearing on the sources of metamorphic fluids are discussed. This paper served as a review and an introduction to the next paper by D. Jackson. Jackson presented carbon isotope data from gases extracted from fluid inclusions in South Indian granulites. The uniformly low Delta C-13 values (minus 10 plus or minus 2 per mil) and the greater abundance of CO2 in the incipient charnockites are suggestive of fluid influx from an externally buffered reservoir
    corecore