Optimal labor-market policy in recessions

The authors examine the optimal labor market-policy mix over the business cycle. In a search and matching model with risk-averse workers, endogenous hiring and separation, and unobservable search effort they first show how to decentralize the constrained-efficient allocation. This can be achieved by a combination of a production tax and three labor-market policy instruments, namely, a vacancy subsidy, a layoff tax and unemployment benefits. The authors derive analytical expressions for the optimal setting of each of these for the steady state and for the business cycle. Their propositions suggest that hiring subsidies, layoff taxes and the replacement rate of unemployment insurance should all rise in recessions. The authors find this confirmed in a calibration targeted to the U.S. economy.Unemployment ; Labor market ; Business cycles

The (un)importance of unemployment fluctuations for welfare

This paper develops a real business cycle model with labor market search and matching frictions, which endogenously links both the cyclical fluctuations and the mean level of unemployment to the aggregate business cycle risk. The key result of the paper is that business cycles are costly for all consumers, regardless of their wealth, yet that unemployment fluctuations themselves are not the source of these costs. Rather fluctuations over the cycle induce higher average unemployment rates as employment is non-linear in job-finding rates and past unemployment. The authors first show this result analytically in special cases. They then calibrate a general equilibrium model with risk-averse asset-holding and liquidity-constrained workers to US data. Also under these more general circumstances, business cycles mean higher unemployment for all workers. The ensuing costs of cycles rise further for liquidity-constrained agents when replacement rates are lower or when workers' skills depend on the length of (un)employment spells.Unemployment ; Welfare ; Business cycles

Optimal Labor-Market Policy in Recessions

We examine the optimal labor market-policy mix over the business cycle. In a search and matching model with risk-averse workers, endogenous hiring and separation, and unobservable search effort we first show how to decentralize the constrained-efficient allocation. This can be achieved by a combination of a production tax and three labor-market policy instruments, namely, a vacancy subsidy, a layoff tax and unemployment benefits. We derive analytical expressions for the optimal setting of each of these for the steady state and for the business cycle. Our propositions suggest that hiring subsidies, layoff taxes and the replacement rate of unemployment insurance should all rise in recessions. We find this confirmed in a calibration targeted to the U.S. economy.unemployment , search and matching , endogenous separations

Exploration of large scale manufacturing of polydimethylsiloxane (PDMS) microfluidic devices

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaves 54-56).Discussion of the current manufacturing process of polydimethylsiloxane (PDMS) parts and the emergence of PDMS use in biomedical microfluidic devices addresses the need to develop large scale manufacturing processes for the fabrication of said devices. Casting PDMS parts is found to be the best mass production process after evaluating several different production methods. Automation of the manufacturing process is introduced as a solution to the need for mass production. Changing variables within the production process and its effects are also discussed with the recommendation being made for using low viscosity pre-cured PDMS, high temperature curing and high vacuum degassing techniques to produce high quality parts at high production rates. The further development of producing two-sided PDMS parts is recommended by investigating the usage of a non-closed aspect limited casting process.by Philip W. Hum.S.B

Optimal Taxation and (Female)-Labor Force Participation over the Cycle

Optimal labor tax results over the cycle are, quantitatively, typically driven by an estimate of the intratemporal elasticity of substitution that governs the reaction of hours worked to business cycle shocks and tax rate changes. A recent literature tries to decompose this intratemporal elasticity into its main components, the "Ins and Outs of Unemployment" (Shimer(2007)) to emphasize the importance of the extensive margin. This paper provides a model that a.) endogenizes all transition rates including firings and quits on the job as well as movements in and out of inactivity, b.) explains the fluctuations in these rates quantitatively while allowing for differences across gender and c.) remains tractable and open to Ramsey-optimal policy. We estimate the model on US-data for the years 1970:1 to 2004:4 and show that the model predicts all labor market flows very well. We apply our model to show that observed labor tax rates over the cycle correspond fairly closely to the implied Ramsey-optimal ones.search theory, unemployment, hours worked

A GIS-Based Approach for Determining Potential Runoff Coefficient and Runoff Depth for the Indian River Lagoon, Florida, USA

The Indian River Lagoon system (IRL), spanning ~40% of Florida’s east coast, is one of the nation’s biggest and most biodiverse estuaries. In 2011, a super algal bloom event occurred in the IRL with total nitrogen and phosphorus levels that exceeded historical levels. Scientists suspect that nonpoint source pollution through surface runoff may have had a significant impact on the recent recurring algal blooms. Digital Elevation Model, land cover/land use, and soil data were used to calculate a runoff coefficient for the IRL drainage basin. Rainfall data were used to calculate runoff depth for the study area between the years of 2006–2016. When the monthly runoff depth data for 2011 were compared to a previous study on the 2011 super algal bloom in the lagoon, areas with high runoff visually matched the areas with higher chlorophyll a concentrations. Land development was a significant variable for determining runoff depth (p < 0.0001), and although used to derive runoff depths, the influence of precipitation was marginally significant (p = 0.06). Significant spatial autocorrelation indicated local trends between land development and runoff depth (p < 0.0001). Outputs will aid with decisions on stormwater management to more sustainable land development planning

First Confirmation of Cougar, Puma concolor, in the Yukon

Cougar (Puma concolor) have been reported from the Yukon as early as 1944. Despite many sightings, no indisputable, physical evidence of Cougar being present in the Yukon had been obtained. Here, we report on the first. In November 2000, a specimen was secured from near Watson Lake, in southeastern Yukon. Whether this specimen, and the numerous sighting records, are indicative of a low-density breeding population in the Yukon, or represent transients, is unknown

Benchmarking inference methods for water quality monitoring and status classification

River water quality monitoring at limited temporal resolution can lead to imprecise and inaccurate classification of physicochemical status due to sampling error. Bayesian inference allows for the quantification of this uncertainty, which can assist decision-making. However, implicit assumptions of Bayesian methods can cause further uncertainty in the uncertainty quantification, so-called second-order uncertainty. In this study, and for the first time, we rigorously assessed this second-order uncertainty for inference of common water quality statistics (mean and 95th percentile) based on sub-sampling high-frequency (hourly) total reactive phosphorus (TRP) concentration data from three watersheds. The statistics were inferred with the low-resolution sub-samples using the Bayesian lognormal distribution and bootstrap, frequentist t test, and face-value approach and were compared with those of the high-frequency data as benchmarks. The t test exhibited a high risk of bias in estimating the water quality statistics of interest and corresponding physicochemical status (up to 99% of sub-samples). The Bayesian lognormal model provided a good fit to the high-frequency TRP concentration data and the least biased classification of physicochemical status (< 5% of sub-samples). Our results suggest wide applicability of Bayesian inference for water quality status classification, a new approach for regulatory practice that provides uncertainty information about water quality monitoring and regulatory classification with reduced bias compared to frequentist approaches. Furthermore, the study elucidates sizeable second-order uncertainty due to the choice of statistical model, which could be quantified based on the high-frequency data.Peer Reviewe

Optimal Taxation and (Female)-Labor Force Participation over the Cycle

Optimal labor tax results over the cycle are, quantitatively, typically driven by an estimate of the intratemporal elasticity of substitution that governs the reaction of hours worked to business cycle shocks and tax rate changes. A recent literature tries to decompose this intratemporal elasticity into its main components, the "Ins and Outs of Unemployment" (Shimer(2007)) to emphasize the importance of the extensive margin. This paper provides a model that a.) endogenizes all transition rates including firings and quits on the job as well as movements in and out of inactivity, b.) explains the fluctuations in these rates quantitatively while allowing for differences across gender and c.) remains tractable and open to Ramsey-optimal policy. We estimate the model on US-data for the years 1970:1 to 2004:4 and show that the model predicts all labor market flows very well. We apply our model to show that observed labor tax rates over the cycle correspond fairly closely to the implied Ramsey-optimal ones