Technological Progress, On-the-Job Search, and Unemployment

This paper studies the impact of long-run productivity growth on job finding and separation rates, and thus the unemployment rate, using a search and matching model. We incorporate disembodied technological progress and on-the-job search into the endogenous job separation model of Mortensen and Pissarides (1994). The incorporation of on-the-job search allows faster growth to reduce unemployment by decreasing the separation rate and inducing job creation. We demonstrate that introducing on-the-job search substantially improves the ability of the Mortensen and Pissarides model to explain the impact of growth on unemployment. Our quantitative analysis shows that our model increases the magnitude of the negative impact of growth on unemployment compared to the standard matching model with disembodied technological progress.

Suzaku Observation of the Diffuse X-Ray Emission from the Open Cluster Westerlund 2: a Hypernova Remnant?

We present the analysis of Suzaku observations of the young open cluster Westerlund 2, which is filled with diffuse X-ray emission. We found that the emission consists of three thermal components or two thermal and one non-thermal components. The upper limit of the energy flux of the non-thermal component is smaller than that in the TeV band observed with H.E.S.S. This may indicate that active particle acceleration has stopped in this cluster, and that the accelerated electrons have already cooled. The gamma-ray emission observed with H.E.S.S. is likely to come from high-energy protons, which hardly cool in contrast with electrons. Metal abundances of the diffuse X-ray gas may indicate the explosion of a massive star in the past.Comment: Accepted for publication in PAS

Technological progress, on-the-job search, and unemployment

This paper studies the impact of long-run productivity growth on job finding and separation rates, and thus the unemployment rate, using a search and matching model. We incorporate disembodied technological progress and on-the-job search into the endogenous job separation model of Mortensen and Pissarides (1994). The incorporation of on-the-job search allows faster growth to reduce unemployment by decreasing the separation rate and inducing job creation. We demonstrate that introducing on-the-job search substantially improves the ability of the Mortensen and Pissarides model to explain the impact of growth on unemployment. Our quantitative analysis shows that our model increases the magnitude of the negative impact of growth on unemployment compared to the standard matching model with disembodied technological progress.The 11th ISER-Moriguchi Prize (2009) Awarded Paper

Glottal Parameters and Some Acoustic Measures in Patients with Laryngeal Pathology.

High speed motion pictures of larynges with different pathologies were taken simultaneously with recordings of the acoustic signals picked up by a contact microphone coupled to the neck. The acoustic signals were displayed on an oscilloscope and photographed onto the same film as the laryngeal images. A semi-automated digital reduction system was employed to reduce the acoustic data and glottal dimensions into digital information. The amplitude of the pressure signal and laryngeal parameters such as glottal area, glottal width, and excursion contours of both folds were calculated and displayed by computer programs. A good agreement was observed between the periodicity of the contact microphone signal and that of glottal area, though the phase relation between the two parameters varied considerably from patient to patient. Relations among the glottal area and other laryngeal parameters mentioned above were considered. It is pointed out that the glottal width function does not represent the glottal area function in many cases with pathologic larynges. The validity of the contact microphone technique for extraction of the fundamental periods of speech is discussed in reference to the acoustic approach to detection of laryngeal pathology. [This study was supported by USPHS Grants NS 08177 and NS 08036.