3,287 research outputs found
Customer Discrimination and Employment Outcomes for Minority Workers
In this paper we investigate the effects of consumer discrimination on the employment and earnings of minorities, particularly blacks. We do so using data from a new survey of employers in four large metropolitan areas in the United States. Our results show that the racial composition of an establishment’s customers has sizable effects on the race of who gets hired, particularly in jobs that involve direct contact with customers. Although we find evidence of customer discrimination in both predominantly white and black establishments, the net effect of such discrimination appears to be some reduction in overall labor demand and wages for blacks. Evidence is also presented which suggests that the role of customer discrimination may be growing more important over time.
Spatial factors and the employment of blacks at the firm level
In this paper we use data from a new survey of over 3,000 employers in four major metropolitan areas to investigate the determinants of black employment and wages at the firm level. We focus specifically on two factors that are likely to influence the spatial distribution of black employment: the proximity of firms to the residential locations of various racial groups and to public transit. We also consider the effects on black employment of other factors, such as employers' skill needs and some likely determinants of their preferences across groups. Our main finding is that employers' proximity to black residences and to public transit increases the likelihood that they will hire black employees. This is true even when we include detailed controls for the skills needed by employers and also for the race of customers and of those responsible for hiring, which independently affect the levels of black employment at firms. Proximity to public transit and especially to black residences accounts for major portions of the higher black employment rates at central-city than suburban firms. The residential effects are relatively strong for employers who recruit through informal methods and weak for those who use newspapers, thus suggesting that information may play a role in the distance effects. We also find some evidence that employers' proximity to black residential populations results in lower wages for workers.
Gibbs free energy difference between the undercooled liquid and the beta-phase of a Ti-Cr alloy
The heat of fusion and the specific heats of the solid and liquid have been experimentally determined for a Ti60Cr40 alloy. The data are used to evaluate the Gibbs free energy difference, DELTA-G, between the liquid and the beta-phase as a function of temperature to verify a reported spontaneous vitrification (SV) of the beta-phase in Ti-Cr alloys. The results show that SV of an undistorted beta-phase in the Ti60Cr40 alloy at 873 K is not feasible because DELTA-G is positive at the temperature. However, DELTA-G may become negative with additional excess free energy to the beta-phase in the form of defects
Gibbs free-energy difference between the glass and crystalline phases of a Ni-Zr alloy
The heats of eutectic melting and devitrification, and the specific heats of the crystalline, glass, and liquid phases have been measured for a Ni24Zr76 alloy. The data are used to calculate the Gibbs free-energy difference, DeltaGAC, between the real glass and the crystal on an assumption that the liquid-glass transition is second order. The result shows that DeltaGAC continuously increases as the temperature decreases in contrast to the ideal glass case where DeltaGAC is assumed to be independent of temperature
Within Cities and Suburbs: Racial Residential Concentration and the Spatial Distribution of Employment Opportunities across Submetropolitan Areas
In this paper, we examine and compare the spatial distributions of jobs and people across submetropolitan areas using data on firms from the Multi-City Study of Urban Inequality and data on people from the U.S. Bureau of the Census. The results indicate that less-educated people and those on public assistance mostly reside in areas with high minority populations. Low-skill jobs are quite scarce in these areas, while the availability of such jobs relative to less-educated people in heavily white suburban areas is high. Large fractions of the low-skill jobs in these metropolitan areas are not accessible by public transit. Furthermore, there is significant variation within both central cities and suburbs in the ethnic composition of residents and in the availability of low-skill jobs. The ability of various minority groups to gain employment in each area depends heavily on the ethnic composition of the particular area.
Interleukin-1ß enhances capsaicin-induced neurogenic vasodilatation in the rat skin
No abstract available
The Magic Number Problem for Subregular Language Families
We investigate the magic number problem, that is, the question whether there
exists a minimal n-state nondeterministic finite automaton (NFA) whose
equivalent minimal deterministic finite automaton (DFA) has alpha states, for
all n and alpha satisfying n less or equal to alpha less or equal to exp(2,n).
A number alpha not satisfying this condition is called a magic number (for n).
It was shown in [11] that no magic numbers exist for general regular languages,
while in [5] trivial and non-trivial magic numbers for unary regular languages
were identified. We obtain similar results for automata accepting subregular
languages like, for example, combinational languages, star-free, prefix-,
suffix-, and infix-closed languages, and prefix-, suffix-, and infix-free
languages, showing that there are only trivial magic numbers, when they exist.
For finite languages we obtain some partial results showing that certain
numbers are non-magic.Comment: In Proceedings DCFS 2010, arXiv:1008.127
Multi-Head Finite Automata: Characterizations, Concepts and Open Problems
Multi-head finite automata were introduced in (Rabin, 1964) and (Rosenberg,
1966). Since that time, a vast literature on computational and descriptional
complexity issues on multi-head finite automata documenting the importance of
these devices has been developed. Although multi-head finite automata are a
simple concept, their computational behavior can be already very complex and
leads to undecidable or even non-semi-decidable problems on these devices such
as, for example, emptiness, finiteness, universality, equivalence, etc. These
strong negative results trigger the study of subclasses and alternative
characterizations of multi-head finite automata for a better understanding of
the nature of non-recursive trade-offs and, thus, the borderline between
decidable and undecidable problems. In the present paper, we tour a fragment of
this literature
Particles held by springs in a linear shear flow exhibit oscillatory motion
The dynamics of small spheres, which are held by linear springs in a low
Reynolds number shear flow at neighboring locations is investigated. The flow
elongates the beads and the interplay of the shear gradient with the nonlinear
behavior of the hydrodynamic interaction among the spheres causes in a large
range of parameters a bifurcation to a surprising oscillatory bead motion. The
parameter ranges, wherein this bifurcation is either super- or subcritical, are
determined.Comment: 4 pages, 5 figure
Direct measurement of shear-induced cross-correlations of Brownian motion
Shear-induced cross-correlations of particle fluctuations perpendicular and
along stream-lines are investigated experimentally and theoretically. Direct
measurements of the Brownian motion of micron-sized beads, held by optical
tweezers in a shear-flow cell, show a strong time-asymmetry in the
cross-correlation, which is caused by the non-normal amplification of
fluctuations. Complementary measurements on the single particle probability
distribution substantiate this behavior and both results are consistent with a
Langevin model. In addition, a shear-induced anti-correlation between
orthogonal random-displacements of two trapped and hydrodynamically interacting
particles is detected, having one or two extrema in time, depending on the
positions of the particles.Comment: 4 pages, 4 figure
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