Estimating Workforce Development Needs for High-Speed Rail in California, Research Report 11-16

This study provides an assessment of the job creation and attendant education and training needs associated with the creation of the California High-Speed Rail (CHSR) network, scheduled to begin construction in September 2012. Given the high profile of national and state commitment to the project, a comprehensive analysis that discusses the education, training, and related needs created during the build out of the CHSR network is necessary. This needs assessment is achieved by means of: 1) analyzing current high-speed rail specific challenges pertaining to 220mph trains; 2) using a more accurate and robust “bottom-up” approach to estimate the labor, education, skills, and knowledge needed to complete the CHSR network; and 3) assessing the current capacity of railroad-specific training and education in the state of California and the nation. Through these analyses, the study identifies the magnitude and attributes of the workforce development needs and challenges that lie ahead for California. The results of this research offer new insight into the training and education levels likely to be needed for the emergent high-speed rail workforce, including which types of workers and professionals are needed over the life of the project (by project phase), and their anticipated educational level. Results indicates that although the education attained by the design engineers of the system signifies the most advanced levels of education in the workforce, this group is comparatively small over the life of the project. Secondly, this report identifies vast training needs for the construction workforce and higher education needs for a managerial construction workforce. Finally, the report identifies an extremely limited existing capacity for training and educating the high-speed rail workforce in both California and in the U.S. generally

Public Expenditure Policy in Bolivia: Growth and Welfare

It has been widely documented that fiscal policy can promote economic growth, when it is based on an efficient provision of pubic capital. But little work has been done, in Bolivia, in relation to the macroeconomic and sectoral impacts of increasing public investment in infrastructure. This paper develops a Dynamic Stochastic General Equilibrium (DSGE) model for a small open economy with five sectors: Non-tradable or services, importable or manufacturing, hydrocarbons, mining and agriculture. The model is parameterized and solved for the Bolivian economy and several interesting scenarios are simulated by changing government expenditures, taxes, country risk, Total Factor Productivity, effectiveness of public capital and terms of trade. This analysis is relevant for the Bolivian economy, because the government is using fiscal policy as one of its main tool to attack poverty and aims to put public investment as the foremost instruments to promote growth and welfare.Fiscal Policy, Infrastructure, Multisector Growth Model

Formation of the First Planetesimals via the Streaming Instability in Globally Turbulent Protoplanetary Disks?

Using self-consistent models of turbulent particle growth in an evolving protoplanetary nebula of solar composition we find that recently proposed local metallicity and Stokes number criteria necessary for the streaming instability to generate gravitationally bound particle overdensities are generally not approached anywhere in the disk during the first million years, an epoch in which meteoritic and observational evidence strongly suggests that the formation of the first planetesimals and perhaps giant planet core accretion is already occurring.Comment: 14 pages, 4 figures, 1 appendix. Accepted to Ap

Constraints on the initial mass, age and lifetime of Saturn's rings from viscous evolutions that include pollution and transport due to micrometeoroid bombardment

The Cassini spacecraft provided key measurements during its more than twelve year mission that constrain the absolute age of Saturn's rings. These include the extrinsic micrometeoroid flux at Saturn, the volume fraction of non-icy pollutants in the rings, and a measurement of the ring mass. These observations taken together limit the ring exposure age to be < a few 100 Myr if the flux was persistent over that time (Kempf et al., 2023). In addition, Cassini observations during the Grand Finale further indicate the rings are losing mass (Hsu et al., 2018; Waite et al., 2018) suggesting the rings are ephemeral as well. In a companion paper (Durisen and Estrada, 2023), we show that the effects of micrometeoroid bombardment and ballistic transport of their impact ejecta can account for these loss rates for reasonable parameter choices. In this paper, we conduct numerical simulations of an evolving ring in a systematic way in order to determine initial conditions that are consistent with these observations.Comment: 31 pages, 19 figures, 2 tables, Published in Icaru

Large mass inflow rates in Saturn's rings due to ballistic transport and mass loading

The Cassini mission provided key measurements needed to determine the absolute age of Saturn's rings, including the extrinsic micrometeoroid flux at Saturn, the volume fraction of non-icy pollutants in the rings, and the total ring mass. These three factors constrain the ring age to be no more than a few 100 Myr (Kempf et al., 2023). Observations during the Cassini Grand Finale also showed that the rings are losing mass to the planet at a prodigious rate. Some of the mass flux falls as "ring rain" at high latitudes. However, the influx in ring rain is considerably less than the total measured mass influx of 4800 to 45000 kg/s at lower latitudes (Waite et al., 2018). In addition to polluting the rings, micrometeoroid impacts lead to ballistic transport, the mass and angular momentum transport due to net exchanges of meteoroid impact ejecta. Because the ejecta are predominantly prograde, they carry net angular momentum outward. As a result, ring material drifts inward toward the planet. Here, for the first time, we use a simple model to quantify this radial mass inflow rate for dense rings and find that, for plausible choices of parameters, ballistic transport and mass loading by meteoroids can produce a total inward flux of material in the inner B ring and in the C ring that is on the order of a few x 10^3 to a few x 10^4 kg/s, in agreement with measurements during the Cassini Grand Finale. From these mass inflow rates, we estimate that the remaining ring lifetime is ~15 to 400 Myr. Combining this with a revised pollution age of ~120 Myr, we conclude that Saturn's rings are not only young but ephemeral and probably started their evolution on a similar timescale to their pollution age with an initial mass of one to a few Mimas masses.Comment: 25 pages, 6 figures, Published in Icaru

Public expenditure policy in Bolivia: Growth and welfare

It has been widely documented that fiscal policy can promote economic growth, when it is based on an efficient provision of pubic capital. But little work has been done, in Bolivia, in relation to the macroeconomic and sectoral impacts of increasing public investment in infrastructure. This paper develops a Dynamic Stochastic General Equilibrium (DSGE) model for a small open economy with five sectors: Non-tradable or services, importable or manufacturing, hydrocarbons, mining and agriculture. The model is parameterized and solved for the Bolivian economy and several interesting scenarios are simulated by changing government expenditures, taxes, country risk, Total Factor Productivity, effectiveness of public capital and terms of trade. This analysis is relevant for the Bolivian economy, because the government is using fiscal policy as one of its main tool to attack poverty and aims to put public investment as the foremost instruments to promote growth and welfare

Is Fiscal Policy Alone Enough for Growth ? A Simulation Analysis for Bolivia

This paper develops a dynamic stochastic general equilibrium (DSGE) model to analyze the growth effects of fiscal policy in Bolivia. It is a multi-sector model with five representative sectors for the Bolivian economy: Non-tradables, importables, hydrocarbons, mining and agriculture. Public capital is included as a production factor in each of these sectors. The model is calibrated and a number of interesting scenarios are simulated by modifying each of the available fiscal policy instruments. In particular, we analyze the sustainability of Bolivian social policy based on government transfers to households along with the short- and long-run implications of fiscal policy for growth and welfare. We find that fiscal policy alone is unable to generate high rates of growth: it must be accompanied by an efficient provision of public capital and productivity boosts in the economic sectors.Fiscal policy, Infrastructure, multi-sector growth model