LABOR MARKET BEHAVIOR IN WASHINGTON: A COINTEGRATION APPROACH

In recent years, the research that investigates impact of employment on other labor related variables has a prominent place in regional science. Generally, it is well understood that new business investment brings changes in population, increased labor force participation rate and migration of new residents. There is mixed research results regarding the extent that new migrants tend to account for new employment. Bartik (1993) found that about one-quarter of the new jobs go to local workers because of the increase in the labor force participation rates of local residents in the long run. He considered the long run effects by estimating the effects of 1% job growth in a certain period on the labor force participation rate seventeen years after the period. In contrast Blanchard and Katz's (1992) research reaches the opposite conclusion - in five to seven years the employment response consists entirely of the migration of new migrants. Their finding is that long-run effect of the job growth on the labor force participation rate is negligible. In this study, from the cointegration time series analysis, we found a long run equilibrium relationship among population, labor force participation rate and employment, in which population is positively related to employment and negatively related to labor force participation rate. The long run effect of a unit change of labor force participation rate (1%) is a decrease of 73,880 in population and the long run effect of a unit change in employment (1000) is an increase of 2,190 in population. We decomposed the time series into stationary components and non-stationary components. The pattern of the stationary component of population is quite similar to that of labor force participation rate while that of employment shows a different fluctuation. From the decomposition, it was obvious that the pattern of stationary component of employment and net migration is quite similar, which means net migration is the short run, temporary response to employment change. The patterns of three years delayed stationary components of population are similar to that of employment and net migration, and the plots correspond to changing economic conditions. According to the change in economic conditions population responds three years later than employment and net migration. We interpreted the non-stationary component of labor force participation rate as reflecting the increasing trend of labor force participation rate in Washington mainly due to a considerable increase in the female labor force participation. The impulse responses of population, employment and labor force participation rate to a one standard deviation shock in employment show permanent increase effects. They settle at different equilibrium value after long term periods. The response of the labor force participation rate to an impulse in employment supports Bartik's finding. Obviously the result is the opposite of Blanchard-Katz's finding that the long-run effect of job growth on the labor force participation rate is negligible. However, since the effect of population is also significantly high, we doubt that the effect of increase in labor force participation rate according to the employment shock covers only local resident labor force.Labor and Human Capital,

First-Order Transition and Critical End-Point in Vortex Liquids in Layered Superconductors

We calculate various thermodynamic quantities of vortex liquids in a layered superconductor by using the nonperturbative parquet approximation method, which was previously used to study the effect of thermal fluctuations in two-dimensional vortex systems. We find there is a first-order transition between two vortex liquid phases which differ in the magnitude of their correlation lengths. As the coupling between the layers increases,the first-order transition line ends at a critical point. We discuss the possible relation between this critical end-point and the disappearance of the first-order transition which is observed in experiments on high temperature superconductors at low magnetic fields.Comment: 9 pages, 5 figure

The nature of solar brightness variations

The solar brightness varies on timescales from minutes to decades. Determining the sources of such variations, often referred to as solar noise, is of importance for multiple reasons: a) it is the background that limits the detection of solar oscillations, b) variability in solar brightness is one of the drivers of the Earth's climate system, c) it is a prototype of stellar variability which is an important limiting factor for the detection of extra-solar planets. Here we show that recent progress in simulations and observations of the Sun makes it finally possible to pinpoint the source of the solar noise. We utilise high-cadence observations from the Solar Dynamic Observatory and the SATIRE model to calculate the magnetically-driven variations of solar brightness. The brightness variations caused by the constantly evolving cellular granulation pattern on the solar surface are computed with the MURAM code. We find that surface magnetic field and granulation can together precisely explain solar noise on timescales from minutes to decades, i.e. ranging over more than six orders of magnitude in the period. This accounts for all timescales that have so far been resolved or covered by irradiance measurements. We demonstrate that no other sources of variability are required to explain the data. Recent measurements of Sun-like stars by CoRoT and Kepler uncovered brightness variations similar to that of the Sun but with much wider variety of patterns. Our finding that solar brightness variations can be replicated in detail with just two well-known sources will greatly simplify future modelling of existing CoRoT and Kepler as well as anticipated TESS and PLATO data.Comment: This is the submitted version of the paper published in Nature Astronom

UV solar irradiance in observations and the NRLSSI and SATIRE-S models

Total solar irradiance and UV spectral solar irradiance have been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the variability to solar magnetic activity. The NRLSSI and SATIRE-S models provide the most comprehensive reconstructions of total and spectral solar irradiance over the period of satellite observation currently available. There is persistent controversy between the various measurements and models in terms of the wavelength dependence of the variation over the solar cycle, with repercussions on our understanding of the influence of UV solar irradiance variability on the stratosphere. We review the measurement and modelling of UV solar irradiance variability over the period of satellite observation. The SATIRE-S reconstruction is consistent with spectral solar irradiance observations where they are reliable. It is also supported by an independent, empirical reconstruction of UV spectral solar irradiance based on UARS/SUSIM measurements from an earlier study. The weaker solar cycle variability produced by NRLSSI between 300 and 400 nm is not evident in any available record. We show that although the method employed to construct NRLSSI is principally sound, reconstructed solar cycle variability is detrimentally affected by the uncertainty in the SSI observations it draws upon in the derivation. Based on our findings, we recommend, when choosing between the two models, the use of SATIRE-S for climate studies

Analysis and Design of Wideband Low Noise Amplifier with Digital Control

The design issues in designing low noise amplifier (LNA) for Software-Defined-Radio (SDR) are reviewed. An inductor-less wideband low noise amplifier aiming at low frequency band (0.2-2GHz) for Software-Defined-Radio is presented. Shunt-shunt LNA with active feedback is used as the first stage which is carefully optimized for low noise and wide band applications. A digitally controlled second stage is employed to provide an additional 12dB gain control. A novel method is proposed to bypass the first stage without degrading input matching. This LNA is fabricated in a standard 0.18 um CMOS technology. The measurement result shows the proposed LNA has a gain range of 6dB-18dB at high gain mode and -12dB-0dB at low gain mode, as well as a –3dB bandwidth of 2GHz. The noise figure (NF) is 3.5-4.5dB in the high gain setting mode. It consumes 20mW from a 1.8V supply

T-junction ion trap array for two-dimensional ion shuttling, storage and manipulation

We demonstrate a two-dimensional 11-zone ion trap array, where individual laser-cooled atomic ions are stored, separated, shuttled, and swapped. The trap geometry consists of two linear rf ion trap sections that are joined at a 90 degree angle to form a T-shaped structure. We shuttle a single ion around the corners of the T-junction and swap the positions of two crystallized ions using voltage sequences designed to accommodate the nontrivial electrical potential near the junction. Full two-dimensional control of multiple ions demonstrated in this system may be crucial for the realization of scalable ion trap quantum computation and the implementation of quantum networks.Comment: 3 pages, 5 figure

Strain effects on the thermal properties of ultra-scaled Si nanowires

The impact of uniaxial and hydrostatic stress on the ballistic thermal conductance ($\kappa_{l}$) and the specific heat ($C_{v}$) of [100] and [110] Si nanowires are explored using a Modified Valence Force Field phonon model. An anisotropic behavior of $\kappa_{l}$ and isotropic nature of $C_{v}$ under strain are predicted for the two wire orientations. Compressive (tensile) strain decreases (increases) $C_{v}$. The $C_{v}$ trend with strain is controlled by the high energy phonon sub-bands. Dominant contribution of the low/mid (low/high) energy bands in [100] ([110]) wire and their variation under strain governs the behavior of $\kappa_{l}$.Comment: 4 Figures, 8 Pages, submitted to AP