Autobiography

As the children of immigrants, my parents were raised in Scandinavian Minnesota. My mother, Verna Ecklund, was a university student for only one year but my father, Thomas Peter Mortensen, graduated from the School of Forestry at the University of Minnesota in 1936. They were married shortly after and moved to Enterprise, Oregon, where I was born in 1939. Enterprise, located in the far northeastern corner of the state, was in cattle ranching country surrounded by one of the most beautiful mountain ranges in the U.S. In these mountains, my father began his career as a lookout officer for the U.S. Forest Service. In the war years, they migrated further west to the Portland area where Dad help build Liberty ships in Mr. Kaiser’s ship yards and Mom provided day care for the children of Rosy the Riveter. After the war, the family, which now included my brother Arne born in 1942, moved to the Hood River Valley 60 miles east of Portland where again my father returned to the practice of forestry. There my brothers and I, who included Irving born in 1947, were raised.Search frictions;

Modeling Matched Job-Worker Flows

What can one infer about labor market flows from matched employer- employee panel data? The purpose of this paper is to sketch possible answers to this question. A general but simple labor market equilibrium model of hire and separation flows is developed in the paper. The model embodies the hypothesis that worker productivity differs across employers and that worker and employer flows reflect responses to these differences in a labor market characterized by friction. In the modeled market, each agent acts optimally taking as given the wage offer distribution and market tightness and these in turn are determined by their collective action. The existence of a labor market equilibrium is established under two different wage determination models: rent sharing and wage posting. A demonstration that market flow parameters, search and recruiting effort functions, and the equilibrium wage distribution can be estimated with matched job-work flow data is the principal contribution of the paper.

Island Matching

A synthesis of the Lucas-Prescott island model and the Mortensen- Pissarides matching model of unemployment is studied. By assumption, all unmatched workers and jobs are randomly assigned to islands at the beginning of each period and the number of matches that form on a particular island is the minimum of the two realizations. When calibrated to the recently observed averages of U.S. unemployment and vacancy rates, the model fits the observed vacancy-unemployment Beveridge relationship very well and implies an implicit log linear relationship between the job finding rate and the vacancy-unemployment relationship with an elasticity near 0.5. The constrained efficient solution to the model is decentralized by a equilibrium outcome in which wages on each island are determined by a modified auction. Although the efficient solution explains only about 25% of the observed volatility in the U.S. vacancy-unemployment ratio, an equilibrium outcome in which wages are determined as the solution to a strategic bargaining game explains almost all of it.

CO2-dependent opening of an inwardly rectifying K+ channel

CO2 chemosensing is a vital function for the maintenance of life that helps to control acid–base balance. Most studies have reported that CO2 is measured via its proxy, pH. Here we report an inwardly rectifying channel, in outside-out excised patches from HeLa cells that was sensitive to modest changes in PCO2 under conditions of constant extracellular pH. As PCO2 increased, the open probability of the channel increased. The single-channel currents had a conductance of 6.7 pS and a reversal potential of –70 mV, which lay between the K+ and Cl– equilibrium potentials. This reversal potential was shifted by +61 mV following a tenfold increase in extracellular [K+] but was insensitive to variations of extracellular [Cl–]. The single-channel conductance increased with extracellular [K+]. We propose that this channel is a member of the Kir family. In addition to this K+ channel, we found that many of the excised patches also contained a conductance carried via a Cl–-selective channel. This CO2-sensitive Kir channel may hyperpolarize excitable cells and provides a potential mechanism for CO2-dependent inhibition during hypercapnia

Equilibrium Wage and Employment Dynamics in a Model of Wage Posting without Commitment

A rich but tractable variant of the Burdett-Mortensen model of wage setting behavior is formulated and a dynamic market equilibrium solution to the model is defined and characterized. In the model, firms cannot commit to wage contracts. Instead, the Markov perfect equilibrium to the wage setting game, characterized by Coles (2001), is assumed. In addition, firm recruiting decisions, firm entry and exit, and transitory firm productivity shocks are incorporated into the model. Given that the cost of recruiting workers is proportional to firm employment, we establish the existence of an equilibrium solution to the model in which wages are not contingent on firm size but more productive employers always pay higher wages. Although the state space, the distribution of workers over firms, is large in the general case, it reduces to a scalar that can be interpreted as the unemployment rate in the special case of homogenous firms. Furthermore, the equilibrium is unique. As the dimension of the state space is equal to the number of firms types in general, an (approximate) equilibrium is computable.wage dispersion, wage setting, rank-preserving equilibrium