Skill Heterogeneity and Aggregate Labor Market Dynamics

What determines the comovements of aggregate employment and wages? This classic question in macroeconomics has received renewed attention since the Great Recession, when real wages did not fall despite a crash in employment. This paper proposes a microfoundation for the short-run dynamics of aggregate labor markets which relies on worker heterogeneity. I develop a model in which workers differ in their skills for various occupations, sectors employ occupations with different weights in production, and skills are imperfectly transferable. When shocks are concentrated in particular sectors, the extent to which workers can reallocate across the economy determines aggregate labor market dynamics. I apply the model to study the recession of 2008-09. I estimate the distribution of worker skills using two-period panel data prior to the recessions. Shocking the estimated model with sector-level TFP series replicates the increase in aggregate wages in 2008-09, and decline in 1990-91. The model implies that if either the composition of sector shocks or the distribution of skills in the economy had been the same in the 2008-09 recession as in the 1990-91 recession, real wages would have fallen, while employment would have declined less. This is because skills became less transferable between the 1980s and 2000s. In addition, the declining sectors during 2008-09 all employed a similar mix of skills, which induced many low-skill workers to leave the labor force and limited downward wage pressure on the rest of the economy. Finally, the model suggests a reduced form method to correct aggregate wages for selection in the human capital of workers, which accounts for cyclical job downgrading by focusing on the wage movements of occupation-stayers and recovers wage declines during the Great Recession

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

Studies on the Role of Solar Ultraviolet Radiation in Natural Water Purification by Aquatic Ecosystems

The possibility that pollution might deplete the stratospheric ozone layer and intensify solar UV at the earth\u27s surface focuses attention on the role of solar UV in the various ecosystems at the earth\u27s surface. Previous studies suggested that solar UV might contribute to bacterial die off in wastewater and the studies reported here were directed toward elucidating the action of solar UV in natural waters. It has been assumed that solar UV action on aquatic ecosystems can be evaluated (using proper models) on the basis of the following four independently measurable quantities: I) the intensity of solar UV at the water surface, 2) the attenuation of the UV in the water column, 3) the position of the critical organisms in the water, and 4) the sensitivity of the individual organisms to solar UV exposure. These four factors have been investigated on a continuing basis and the results of measurements have been utilized along with special field and laboratory experiments to assess UV-B actions. Field work has focused on the succession of organisms, their locations in the water column, a,d under more controlled conditions, the killing of E. coli by natural sunlight. Laboratory work has included studies of UV-B lethality, its ability to stimulate positioning responses, and its depression of the photosynthetic activity of algae. Laboratory and field observations have been interpreted through models and our results are consistent with the hypothesis that solar UV is a significant agent for the aquatic microorganisms we have tested

A Principal’s Dilemma: Instructional Leader or Manager

This study focuses on the emphasis principals’ place on the design and delivery of curriculum and instruction on individual campuses and the extent federal regulation has impacted principal behaviors as instructional leaders. The transformation from the principal’s role of manager to that which is inclusive of instructional leadership is due to the steady increase of the regulations governing the accountability system culminating in No Child Left Behind. In fact, “ … one in three principals says implementation of NCLB is the most pressing issue he or she is facing” (Sergiovanni, 2009, p. 44)

Memantine Improves Attentional Processes in Fragile X-Associated Tremor/Ataxia Syndrome: Electrophysiological Evidence from a Randomized Controlled Trial.

Progressive cognitive deficits are common in patients with fragile X-associated tremor/ataxia syndrome (FXTAS), with no targeted treatment yet established. In this substudy of the first randomized controlled trial for FXTAS, we examined the effects of NMDA antagonist memantine on attention and working memory. Data were analyzed for patients (24 in each arm) who completed both the primary memantine trial and two EEG recordings (at baseline and follow-up) using an auditory "oddball" task. Results demonstrated significantly improved attention/working memory performance after one year only for the memantine group. The event-related potential P2 amplitude elicited by non-targets was significantly enhanced in the treated group, indicating memantine-associated improvement in attentional processes at the stimulus identification/discrimination level. P2 amplitude increase was positively correlated with improvement on the behavioral measure of attention/working memory during target detection. Analysis also revealed that memantine treatment normalized the P2 habituation effect at the follow-up visit. These findings indicate that memantine may benefit attentional processes that represent fundamental components of executive function/dysfunction, thought to comprise the core cognitive deficit in FXTAS. The results provide evidence of target engagement of memantine, as well as therapeutically relevant information that could further the development of specific cognitive or disease-modifying therapies for FXTAS

Greenspace, stress, and health: how is epigenetics involved?

Most expositions of the association between green space and overall health and well-being focus on psychosocial mechanisms. However, discussions of the biological underpinnings of the exposure to green space and health implications are limited. In this paper, we highlight the role epigenetics plays in the manifestation or suppression of stress, in addition to some of the proposed epigenetic mechanisms through which green space mitigates stress. The Health: Epigenetics, Greenspace and Stress (HEGS) model is introduced to explicate this association, and suggestions for research to build the evidence base in this area are discussed