A High Power and Ultrahigh Frequency Mode-Locked Laser Monolithically Integrated with an SOA

We report 628 GHz and 1.20 THz pulse repetition frequencies with 142 mW peak powers from a passively mode-locked side-wall SGDBR laser integrated with an SOA, demonstrating high reproducibility, controllability and a wide operation range

Redundancies in an industry in transition: who gets fired and why? Evidence from one consumer-goods industry in Russia

Does employee productivity explain why during a period of crisis firms fired relatively more blue-collar than white-collar workers and why, when conditions improved, they began to hire relatively more blue collars? Are redundancies targeted towards the least productive workers? Was firms’ behaviour profit maximising? These questions are investigated in the extreme circumstances of the footwear industry in Russia in the period 1994-2000. Firms in this industry underwent a major upheaval in these years. Part of their response was to downsize the blue-collar workforce more severely than the whitecollars. Was this because (a) white collar employees had higher marginal productivity or (b) because the technical rate of substitution of white collar labour with blue collar labour was greater than the factor price ratio of these two inputs If it turns out that the marginal productivity of white collar employees was the higher, we could conclude that they were embodying more human capital (Becker, 1962); if they were no more productive than blue collars, this could mean that they had been privileged during downsizing for some institutional reasons, e.g. a prior commitment towards higher-ranking staff (Lazear, 1979; Lazear and Rosen, 1981). If it turns out that the technical rate of substitution of white collar labour with blue collar labour was greater than their factor price ratio, this would suggest that the firms’ downsizing policies were consistent with profit-maximising precepts. Russian footwear is a suitable industry for investigation because there are many units, which use a standard technology, and with relatively little political interference. The paper uses Translog and Cobb Douglas production functions with ordinary least squares, two-step least squares and stochastic frontier analysis, both in a panel and in a cross-section setting. Results show that white collar employees were not only more productive than blue collar employees but also the technical rate of substitution of white collar labour with blue collar labour was greater than the factor price ratio of these two inputs. This suggests that even in a turbulent period and with a Soviet heritage, the firms behaved as profit-maximising agents. Institutional factors may also have operated, but they do not need to be invoked in explaining the data.Productivity, blue collars, white collars, transition, footwear

Does the color of the collar matter? Firm specific human capital and post-displacement outcomes

We investigate whether the costs of job displacement differ between blue collar and white collar workers. In the short run earnings and employment losses are substantial for both groups but stronger for white collar workes. In the long run, there are only weak effects for blue collar workers but strong and persistent effects for white collars. This is consistent with the idea that firm-specific human capital and internal labor markets are more important in white-collar than in blue collar jobs.Firm Specific Human Capital, Plant Closures, Matching

Constraints on Exotic Heavily Ionizing Particles from the Geological Abundance of Fullerenes

The C_{60} molecule exhibits a remarkable stability and inertness that leads to its survival in ancient carbonaceous rocks initially subject to the high temperatures requisite for its formation. Elementary particles having very high electronic stopping powers can similarly form C_{60} and higher fullerenes in their wake. Combined, these two features point at the possibility of using the C_{60} presence (or absence) in selected bulk geological samples as a new type of solid-state nuclear track detector, with applications in astro-particle physics.Comment: Final version (few modifications). Phys. Rev. Lett. (in press). 4 pages LaTeX, 1 eps figure embedde

Analysing the Gender Wage Gap Using Personnel Records of a Large German Company

We use monthly personnel records of a large German company to analyse the gender wage gap (GWG). Main findings are: (1) the unconditional GWG is 15 percent for blue-collar and 26 percent for white-collar workers; (2) conditional on tenure, entry age, schooling, and working hours, the GWG is 13 percent for blue-collar as well as for white-collar workers; (3) after additionally controlling for hierarchical levels, the GWG is less than 4 percent for blue-collar and 8 percent for white-collar workers; (4) Oaxaca decompositions reveal that the unexplained part of the GWG is 87 percent for blue-collar workers and 46 percent for white-collar workers; (5) males have larger absolute wage growths than females; (6) the relative GWG gets larger with tenure for blue-collar but smaller for white-collar workers; (7) individual absenteeism has no significant impact on the GWG; (8) the gender gap in absenteeism is between 26 and 46 percent. Overall, the results are consistent with statistical discrimination explanations of the gender wage gap, though we cannot rule out other forms of discrimination. A simple model within the context of absenteeism and statistical discrimination is offered.absenteeism, gender, personnel data, statistical discrimination, wage differentials

Does the Color of the Collar Matter? Firm Specific Human Capital and Post-Displacement Outcomes

We investigate whether the costs of job displacement differ between blue collar and white collar workers. In the short run earnings and employment losses are substantial for both groups but stronger for white collar workers. In the long run, there are only weak effects for blue collar workers but strong and persistent effects for white collars. This is consistent with the idea that firm-specific human capital and internal labor markets are more important in white-collar than in blue collar jobs.firm specific human capital, plant closures, matching