Nitrogen distribution by globin

This and other experiences with the tryptophane method of Fürth and Nobel led us to doubt seriously the reliability of quantitative data obtained by its application. When, therefore, just as we completed our work with it, Folin and Looney (6) described another and apparently better method of determination, a method based upon a different color reaction and capable moreover of convenient combination with a quantitative procedure for tyrosine, it seemed to us worth while to review the problem again. With the aid of this newer method we have now determined the tryptophane and tyrosine content of two series of globin preparations, and have, we believe, settled fairly decisively the proportion of these amino-acids yielded by the pure protein. We have also taken occasion to determine by the method of Van Slyke the general distribution of nitrogen in the globin molecule

On the Negative Correlation Between Performance and Experience and Education

We consider a model where a worker's productivity must exceed some lower bound for himto satisfy the minimum qualifications for a particular job. If the worker's productivity exceeds some upper bound he is promoted. We assume the productivity of every worker increases with experience, tenure and education. This relationship differs across workers. We present distributions of workers with the property that, among workers on a particular job, education, experience, or tenure is negatively correlated with productivity; even though for any single worker on that job those demographic characteristics have strongly positive effects on productivity. The result is due to the effect of the job assignment rule on the distribution of workers on the job.

Validating Hiring Criteria

We construct a model in which firms use workers' productivities in determining their job assignments. A worker's productivity must exceed some lower bound to satisfy the minimum qualifications for a particular job. If the worker's productivity exceeds some upper bound he is promoted. Under these conditions it is possible that the better educated and more experienced individuals would be the least productive workers on every job, even though, for each worker, education and experience increases his productivity. Whether this anomalous result occurs depends on the underlying distribution of ability in the population and the job assignment policy delineated above. One implication of our analysis is that firms that use hiring criteria that accurately predict a worker's success on the job may not be able to validate those criteria through measurements of the performance of the workers that they had hired. EEOC rules that require hiring criteria to be validated in that fashion may penalize firms with the most efficient hiring and promotion standards.

Interstitial crime analysis

Crime on public transport can be very difficult to analyse. 'Stealth crimes' like pick-pocketing present a particular challenge because victims often have an imprecise knowledge of the location and time of the offence. In this scenario crime has typically been recorded as happening at the reporting station (often at the ‘end of line’) which skews any analysis of the collective crime locations. Interstitial crime analysis (ICA) is a technique which overcomes this problem and improves the estimation of the spatial distribution of crime on networks when the exact location of offences is unknown. Based on the aoristic analysis technique (devised to estimate the temporal distribution of crime when only a time period is known), ICA is used to estimate the location of crimes in the interstices – the intervening spaces - of a network when the location is unknown

"Building" exact confidence nets

Confidence nets, that is, collections of confidence intervals that fill out the parameter space and whose exact parameter coverage can be computed, are familiar in nonparametric statistics. Here, the distributional assumptions are based on invariance under the action of a finite reflection group. Exact confidence nets are exhibited for a single parameter, based on the root system of the group. The main result is a formula for the generating function of the coverage interval probabilities. The proof makes use of the theory of "buildings" and the Chevalley factorization theorem for the length distribution on Cayley graphs of finite reflection groups.Comment: 20 pages. To appear in Bernoull

Extending the CRESST-II commissioning run limits to lower masses

Motivated by the recent interest in light WIMPs of mass ~O(10 GeV), an extension of the elastic, spin-independent WIMP-nucleon cross-section limits resulting from the CRESST-II commissioning run (2007) are presented. Previously, these data were used to set cross-section limits from 1000 GeV down to ~17 GeV, using tungsten recoils, in 47.9 kg-days of exposure of calcium tungstate. Here, the overlap of the oxygen and calcium bands with the acceptance region of the commissioning run data set is reconstructed using previously published quenching factors. The resulting elastic WIMP cross section limits, accounting for the additional exposure of oxygen and calcium, are presented down to 5 GeV.Comment: 4 pages, 4 figure