Wage Structure, Raises and Mobility: International Comparisons of the Structure of Wages Within and Across Firms

The returns to talent or performance have grown over time in developed countries. Is talent concentrated in a few firms or are firms virtual microcosms of the economy, each having close to identical distributions of talent? The data show that talent is not concentrated in a few companies, but is widely dispersed across companies. Wage dispersion within firms is nearly as high as the wage dispersion overall. The standard deviation of wages within the firm is about 80% of the standard deviation across all workers in the economy. Firms are more similar than they are dissimilar, but they are not identical: the firm mean wage displays considerable dispersion across the population of firms. There is evidence that talent is becoming more concentrated over time within some firms relative to others. In four countries that estimated wage regressions with firm fixed effects, the firm fixed effects are contributing more to the R-squared of the wage regression over time. Law firms have more lawyers than janitors. Janitorial firms have more janitors than lawyers and the differences between firms have become more pronounced. Still, the variance of wages within the average firms remains high.

Personnel Economics: The Economist's View of Human Resources

Personnel economics drills deeply into the firm to study human resource management practices like compensation, hiring practices, training, and teamwork. Many questions are asked. Why should pay vary across workers within firms--and how "compressed" should pay be within firms? Should firms pay workers for their performance on the job or for their skills or hours of work? How are pay and promotions structured across jobs to induce optimal effort from employees? Why do firms use teams and how are teams used most effectively? How should all these human resource management practices, from incentive pay to teamwork, be combined within firms? Personnel economics offers new tools and new answers to these questions. In this paper, we display the tools and principles of personnel economics through a series of models aimed at addressing the questions posed above. We focus on the building blocks that form the foundation of personnel economics: the assumptions that both the worker and the firm are rational maximizing agents; that labor markets and product markets must reach some price-quantity equilibrium; that markets are efficient or that market failures have introduced inefficiencies; and that the use of econometrics and experimental techniques has advanced our ability to identify underlying causal relationships.

The value of bosses

How and by how much do supervisors enhance worker productivity? Using a company-based data set on the productivity of technology-based services workers, supervisor effects are estimated and found to be large. Replacing a boss who is in the lower 10% of boss quality with one who is in the upper 10% of boss quality increases a team’s total output by more than would adding one worker to a nine member team. Workers assigned to better bosses are less likely to leave the firm. A separate normalization implies that the average boss is about 1.75 times as productive as the average worker

Plasma Neuronal Exosomal Levels of Alzheimer\u27s Disease Biomarkers in Normal Aging

Plasma neuronal exosomal levels of pathogenic Alzheimer\u27s disease (AD) proteins, cellular survival factors, and lysosomal proteins distinguish AD patients from control subjects, but changes in these exosomal proteins associated with normal aging have not been described for cognitively intact subjects. Plasma neuronal exosomal levels of P-T181-tau, P-S396-tau, Aβ1-42, cathepsin D, repressor element 1-silencing transcription factor, and neurogranin were quantified longitudinally in cognitively intact older adults using two samples collected at 3- to 11-year intervals. Except for P-S396-tau, exosomal protein levels changed significantly with aging, but were largely outside the range observed in AD patients

Stepwise Acquisition of Pyrimethamine Resistance in the Malaria Parasite

The spread of high-level pyrimethamine resistance in Africa threatens to curtail the therapeutic lifetime of antifolate antimalarials. We studied the possible evolutionary pathways in the evolution of pyrimethamine resistance using an approach in which all possible mutational intermediates were created by site-directed mutagenesis and assayed for their level of drug resistance. The coding sequence for dihydrofolate reductase (DHFR) from the malaria parasite Plasmodium falciparum was mutagenized, and tests were carried out in Escherichia coli under conditions in which the endogenous bacterial enzyme was selectively inhibited. We studied 4 key amino acid replacements implicated in pyrimethamine resistance: N51I, C59R, S108N, and I164L. Using empirical estimates of the mutational spectrum in P. falciparum and probabilities of fixation based on the relative levels of resistance, we found that the predicted favored pathways of drug resistance are consistent with those reported in previous kinetic studies, as well as DHFR polymorphisms observed in natural populations. We found that 3 pathways account for nearly 90% of the simulated realizations of the evolution of pyrimethamine resistance. The most frequent pathway (S108N and then C59R, N51I, and I164L) accounts for more than half of the simulated realizations. Our results also suggest an explanation for why I164L is detected in Southeast Asia and South America, but not at significant frequencies in Africa.Organismic and Evolutionary Biolog

Accelerating slip rates on the Puente Hills blind thrust fault system beneath metropolitan Los Angeles, California, USA

Slip rates represent the average displacement across a fault over time and are essential to estimating earthquake recurrence for probabilistic seismic hazard assessments. We demonstrate that the slip rate on the western segment of the Puente Hills blind thrust fault system, which is beneath downtown Los Angeles, California (USA), has accelerated from ∼0.22 mm/yr in the late Pleistocene to ∼1.33 mm/yr in the Holocene. Our analysis is based on syntectonic strata derived from the Los Angeles River, which has continuously buried a fold scarp above the blind thrust. Slip on the fault beneath our field site began during the late-middle Pleistocene and progressively increased into the Holocene. This increase in rate implies that the magnitudes and/or the frequency of earthquakes on this fault segment have increased over time. This challenges the characteristic earthquake model and presents an evolving and potentially increasing seismic hazard to metropolitan Los Angeles