ECONOMIC DISADVANTAGES OF BLACKS IN HIGH BLACK PROPORTION CITIES

This paper proposes wage premiums for jobs in high black proportion cities as a source of the continuing economic disadvantages for poor blacks. The estimated hedonic model of individual wages confirms the presence of such wage premiums which result in high labor costs and economic stagnation in a black-concentrated region, while the regional black ratio regression indicates a significant statistical correlation between a region¡¯s black ratio and its disamenities. From the empirical results emerge the following conclusions: First, the equality of the estimated wage premiums for high black ratio between blacks and whites precludes direct prejudice-based discrimination. A caveat, however, is that the full wage premiums are conferred upon workers moving freely across regions in search of better wages and amenities, not applying to the mobility-restricted or the non-employed. Second, the wage premiums for high black ratio, causing economic stagnation of a black- concentrated region, constitute a statistical discrimination against blacks. This is because, given the pre-existing poverty among inner city blacks, the victims of the regional economic decline are mainly those unskilled, poor blacks who suffer non-employment due to inadequate resources for job search and mobility.Wage Premium, Black-concentrated Region, Statistical Discrimination

Holographic Monopole Catalysis of Baryon Decay

We study how monopole catalysis of baryon decay is realized in holographic QCD. Physics of monopole catalysis becomes much simpler in holographic description as it occurs due to the violation of the Bianchi identity for the 5D gauge symmetry when magnetic monopole is present. In holographic QCD we find a unified picture of the baryon number violation under magnetic monopole or electroweak sphaleron, giving a new mechanism of baryon number violation. We also embed our set-up in the string theory model by Sakai and Sugimoto.Comment: 18 pages, v2: references adde

Lineal Trails of D2-D2bar Superstrings

We study the superstrings suspended between a D2- and an anti-D2-brane. We quantize the string in the presence of some general configuration of gauge fields over the (anti-)D-brane world volumes. The interstring can move only in a specific direction that is normal to the difference of the electric fields of each (anti-)D-branes. Especially when the electric fields are the same, the interstring cannot move. We obtain the condition for the tachyons to disappear from the spectrum.Comment: 15 pages with 4 figures, referenced added, Sec. 5 on the spectrum made cleare

String Pair Creations in D-brane Systems

We investigate the criterion, on the Born-Infeld background fields, for the open string pair creation to occur in D$p$-(anti-)D$p$-brane systems. Although the pair creation occurs generically in both D$p$-D$p$ and D$p$-anti-D$p$ systems for the cases which meet the criterion, it is more drastic in D$p$-anti-D$p$-brane systems by some exponential factor depending on the background fields. Various configurations exhibiting pair creations are obtained via duality transformations. These include the spacelike scissors and two D-strings (slanted at different angles) passing through each other. We raise the scissors paradox and suggest a resolution based on the triple junction in IIB setup.Comment: V2. 1+28 pages, 5 figures in JHEP3, minor changes, added reference