The Vintage Effect in TPF-Growth: An Analysis of the Age Structure of Capital

The age structure of capital plays an important role in the measurement of productivity.It has been argued that the slowdown in the 1970 s can be ascribed to the aging of the stock of capital.In this paper we incorporate the age structure in productivity measurement.One proposition proves that Nelson s (1964) formula is only an approximation.Our final proposition shows that inclusion of the vintage effect prompts an upward correction of measured productivity growth in times of an aging stock of capital.Here capital ages if the investment/capital ratio falls short of the inverse of the capital age, as a first proposition shows.The analysis rests on a rigorous accounting for vintages.We translate the Bureau of Economic Analysis age of capital data into a measure of rates of obsolescence.Empirically, the correction of productivity growth for the vintage effect requires an estimate of the obsolescence and depreciation parameters on the basis of age data.The results indicate that the use of capital stock in efficiency units does cause some smoothing of Total Factor Productivity growth over time.In the 1950s, when investment accelerated, the vintage-adjusted capital growth rate well exceeded the BEA growth rate, and vintageadjusted TFP growth is significantly lower than unadjusted TFP growth.The measured productivity slowdown of the 1970s is somewhat ameliorated.capital;productivity;growth;expenditure;tfp

The Vintage Effect in TPF-Growth:An Analysis of the Age Structure of Capital

The age structure of capital plays an important role in the measurement of productivity.It has been argued that the slowdown in the 1970 s can be ascribed to the aging of the stock of capital.In this paper we incorporate the age structure in productivity measurement.One proposition proves that Nelson s (1964) formula is only an approximation.Our final proposition shows that inclusion of the vintage effect prompts an upward correction of measured productivity growth in times of an aging stock of capital.Here capital ages if the investment/capital ratio falls short of the inverse of the capital age, as a first proposition shows.The analysis rests on a rigorous accounting for vintages.We translate the Bureau of Economic Analysis age of capital data into a measure of rates of obsolescence.Empirically, the correction of productivity growth for the vintage effect requires an estimate of the obsolescence and depreciation parameters on the basis of age data.The results indicate that the use of capital stock in efficiency units does cause some smoothing of Total Factor Productivity growth over time.In the 1950s, when investment accelerated, the vintage-adjusted capital growth rate well exceeded the BEA growth rate, and vintageadjusted TFP growth is significantly lower than unadjusted TFP growth.The measured productivity slowdown of the 1970s is somewhat ameliorated

Analyzing the Labor Market Outcomes of Occupational Licensing

Recent assessments of occupational licensing have shown varying effects of the institution on labor-market outcomes. This study revisits the relationship between occupational licensing and labor-market outcomes by analyzing a new topical module to the Survey of Income and Program Participation. Relative to previously available data, the topical module offers more detailed information on occupational licensing attainment, with larger sample sizes and access to richer sets of person-level characteristics. We find that those with a license earn higher pay, are more likely to be employed, and have a higher probability of employer-sponsored health insurance offers

An independently validated nomogram for isocitrate dehydrogenase-wild-type glioblastoma patient survival.

BackgroundIn 2016, the World Health Organization reclassified the definition of glioblastoma (GBM), dividing these tumors into isocitrate dehydrogenase (IDH)-wild-type and IDH-mutant GBM, where the vast majority of GBMs are IDH-wild-type. Nomograms are useful tools for individualized estimation of survival. This study aimed to develop and independently validate a nomogram for IDH-wild-type patients with newly diagnosed GBM.MethodsData were obtained from newly diagnosed GBM patients from the Ohio Brain Tumor Study (OBTS) and the University of California San Francisco (UCSF) for diagnosis years 2007-2017 with the following variables: age at diagnosis, sex, extent of resection, concurrent radiation/temozolomide (TMZ) status, Karnofsky Performance Status (KPS), O6-methylguanine-DNA methyltransferase (MGMT) methylation status, and IDH mutation status. Survival was assessed using Cox proportional hazards regression, random survival forests, and recursive partitioning analysis, with adjustment for known prognostic factors. The models were developed using the OBTS data and independently validated using the UCSF data. Models were internally validated using 10-fold cross-validation and externally validated by plotting calibration curves.ResultsA final nomogram was validated for IDH-wild-type newly diagnosed GBM. Factors that increased the probability of survival included younger age at diagnosis, female sex, having gross total resection, having concurrent radiation/TMZ, having a high KPS, and having MGMT methylation.ConclusionsA nomogram that calculates individualized survival probabilities for IDH-wild-type patients with newly diagnosed GBM could be useful to physicians for counseling patients regarding treatment decisions and optimizing therapeutic approaches. Free software for implementing this nomogram is provided: https://gcioffi.shinyapps.io/Nomogram_For_IDH_Wildtype_GBM_H_Gittleman/

A robotic end effector for inspection of storage tanks

The structural integrity of waste storage tanks is of primary importance to the DOE, and is one aspect of the High-Level Waste Tank Remediation focus area. Cracks and/or corrosion damage in the inner tank walls can lead to the release of dangerous substances into the environment. The detection and sizing of corrosion and cracking in steel tank walls through remote non destructive evaluation (NDE) is the primary focus of this work

Depinning transition in type-II superconductors

The surface impedance Z(f) of conventional isotropic materials has been carefully measured for frequencies f ranging from 1 kHz to 3 MHz, allowing a detailed investigation of the depinning transition. Our results exhibit the irrelevance of classical ideas to the dynamics of vortex pinning. We propose a new picture, where the linear ac response is entirely governed by disordered boundary conditions of a rough surface, whereas in the bulk vortices respond freely. The universal law for Z(f) thus predicted is in remarkable agreement with experiment, and tentatively applies to microwave data in YBaCuO films.Comment: 4 pages, 4 figures, 14 reference

Mind the Gap: Experimental Tests to Improve Efficacy of Fladry for Nonlethal Management of Coyotes

Coyotes (Canis latrans) are the top predator of livestock in the contiguous United States. Developing more effective nonlethal tools to prevent coyote depredation will facilitate coexistence between livestock producers and coyotes. Fladry is a nonlethal deterrent designed to defend livestock by creating a visual barrier to wolves (C. lupus). Fladry may also be effective with coyotes, but large gap spacing between flags may reduce its efficacy. To address this issue, we performed 2 experiments on captive coyotes using fladry modified to reduce gap spacing at the U.S. Department of Agriculture, Predator Research Facility in Millville, Utah, USA, during 2015–2016 and 2017–2018. In 2015–2016, we tested 2 styles for attaching flags (top‐knot and shower‐curtain) to the rope‐line that reduce gaps by preventing coiling of individual flags. In 2017–2018, we tested the efficacy of gap spacing (27.9 cm vs. 45.7 cm) between flags for preventing coyote crossings. For both tests, we compared the time until coyotes crossed the fladry between treatment types. We found no differences in time to crossing between the 2 attachment designs. In our second experiment, fladry with smaller gaps between flags had greater efficacy of preventing coyote crossings than did fladry with larger gaps. Our results also indicated that for each additional minute coyotes spent interacting with fladry overall (i.e., increased persistent behavior), survival of the barrier decreased. These results suggest that persistent coyotes may overcome neophobia more rapidly than coyotes that do not exhibit persistent behaviors. Furthermore, use of top‐knot fladry and coyote‐width spacing will increase protection of livestock from coyotes

Composite vortex model of the electrodynamics of high-TcT_c superconductor

We propose a phenomenological model of vortex dynamics in which the vortex is taken as a composite object made of two components: the vortex current which is massless and driven by the Lorentz force, and the vortex core which is massive and driven by the Magnus force. By combining the characteristics of the Gittleman-Rosenblum model (Phys. Rev. Lett. {\bf 16}, 734 (1966)) and Hsu's theory of vortex dynamics (Physica {\bf C 213},305 (1993)), the model provides a good description of recent far infrared measurements of the magneto-conductivity tensor of superconducting YBa$_2$Cu$_3$O$_{7-\delta }$ films from 5 cm$^{-1}$ to 200 cm$^{-1}$.Comment: LaTex file (12 pages) + 3 Postscript figures, uuencoded. More information on this paper, please check http://www.wam.umd.edu/~lihn/newmodel