Extragalactic radio source evolution under the dual-population unification scheme

We show that a dual-population unification scheme provides a successful paradigm with which to describe the evolution and beaming of all bright extragalactic radio sources. The paradigm consists of two intrinsic radio-source populations, based on the two distinct radio-galaxy morphologies of Fanaroff-Riley classes I and II. These represent the `unbeamed' or `side-on' parent populations of steep radio spectra; the `beamed' source types including flat-spectrum quasars and BL Lac objects, arise through the random alignment of their radio-axis to our line-of-sight where Doppler-beaming of the relativistic radio jets produces highly anisotropic radio emission.Comment: 18 pages & 18 postscript figures, accepted for publication in MNRA

Arc guidance development work for tack-welded joints

DOWNSTREAM HEAT TRANSFER OF UPSTREAM MASS INJECTION IN SUPERSONIC LAMINAR BOUNDARY LAYER FLO

The correlation function of radio sources

We investigate the large-scale clustering of radio sources in the Green Bank and Parkes-MIT-NRAO 4.85 GHz surveys by measuring the angular two-point correlation function w(\theta). Excluding contaminated areas, the two surveys together cover 70 per cent of the whole sky. We find both surveys to be reasonably complete above 50 mJy. On the basis of previous studies, the radio sources are galaxies and radio-loud quasars lying at redshifts up to z \sim 4, with a median redshift z \sim 1. This provides the opportunity to probe large-scale structures in a volume far larger than that within the reach of present optical and infrared surveys. We detect a clustering signal w(\theta) \approx 0.01 for \theta = 1\degr. By assuming an evolving power-law spatial correlation function in comoving coordinates \xi(r_c,z) = ( r_c / r_0 )^{-\gamma} (1+z)^{\gamma-(3+\epsilon)}, where \gamma = 1.8, and the redshift distribution N(z) of the radio galaxies, we constrain the r_0--\epsilon parameter space. For `stable clustering' (\epsilon = 0), we find the correlation length r_0 \approx 18 Mpc/h, larger than the value for nearby normal galaxies and comparable to the cluster-cluster correlation length.Comment: 8 pages, 7 ps figures included, LaTeX (mn,sty). Accepted by MNRA

Results of literature search on dielectric properties and electron interaction phenomena related to spacecraft charging

The objective of the literature search was to determine the required material properties and electron interaction parameters needed for modeling charge buildup and breakdown in insulators. A brief overview of the results of the literature search is given. A partial list of the references covered is included in a bibliography. Although inorganic insulators were also considered in the search, coverage is limited to the organics, primarily Kapton and Teflon

Walking a tightrope into 2008

Inflation (Finance) ; Housing ; Consumer behavior

Personal-bankruptcy cycles

This paper estimates the dynamics of the personal-bankruptcy rate over the business cycle by exploiting large cross-state variation in recessions and bankruptcies. We find that bankruptcy rates are significantly higher than normal during a recession and rise as a recession persists. After a recession ends, there is a hangover whereby bankruptcy rates begin to fall but remain above normal for several more quarters. Recovery periods see a strong bounce-back effect with bankruptcy rates significantly below normal for several quarters. Despite the significant increases in bankruptcies that occur during recessions, the largest contributor to rising bankruptcies during these periods has tended to be the longstanding upward trend.Bankruptcy ; Finance, Personal

Personal-bankruptcy cycles

This paper estimates the dynamics of the personal-bankruptcy rate over the business cycle by exploiting large cross-state variation. We find that bankruptcy rates are significantly higher than normal during a recession and rise as a recession persists. After a recession ends, there is a hangover whereby bankruptcy rates begin to fall but remain above normal for several more quarters. Recovery periods see a strong bounce-back effect with bankruptcy rates significantly below normal for several quarters. Despite the significant increases in bankruptcies during recessions, the largest contributor to rising bankruptcies during these periods has tended to be the longstanding upward trend.Personal Bankruptcy, Recessions

Structural characterization of YBa(2)Cu(3)O(7)/Y(2)O(3) composite films

Using 4-circle x-ray diffraction and transmission electron microscopy we have studied the microstructure and in-plane orientation of the phases present in thin film composite mixtures of YBa(2)Cu(3)O(7) and Y(2)O(3). We see a high degree of in-plane orientation and have verified a previous prediction for the in-plane order of Y(2)BaCuO(5) on (110) MgO. Transmission electron microscopy shows the composite films to be a mixture of two phases, with YBCO grain sizes of 1 micron. We have also compared our observations of the in-plane order to the predictions of a modified near coincidence site lattice model.Comment: To be published in Journal of Materials Research, (4 pages, 4 jpeg figures