Immigration of Highly Skilled Professionals: Discrimination in Professional Baseball?

Are highly skilled foreign professionals paid differently than their native-born counterparts? To address this question, this study focuses on a particular profession with substantial inflows of immigrants, in which human capital is readily transferrable: Major League Baseball (MLB). Racial discrimination in professional sports has received considerable attention, but it remains to be seen whether there has been differential treatment of foreign athletes. Focusing on a 1997-1998 sample of 557 MLB players, we find that foreign players are indeed treated differently than native-born players, favorably in some respects and unfavorably in others. Moreover, when controlling for birthplace, the extent of racial discrimination must be reconsidered

Solutions to some linear evolutionary systems of equations : study of the double porosity model of fluid flow in fractured rock and its applications.

The present work is a study of three degenerate, linear parabolic systems of equations, each of which represents a version of the so-called double porosity model for underground fluid flows in natural fractured rock. These systems of equations together with initial and boundary conditions describe single-phase flows in fluids, slightly compressible, in large confined homogeneous reservoirs under general conditions including those of typical well tests. Analytic solutions are given as convolutions of initial and source data with fundamental solutions for each system. We establish that the problems are well-posed for all initial conditions likely to arise in practice. We obtain, using the theory of generalized functions, classes of all functions in which solutions exist, are unique and depend continuously on the initial data for appropriate restrictions. We consider two of the models to be the main versions relevant for flows in natural fractured rock, including typical basalt formations. They apply to short-time flows on order of the duration of typical pressure transient tests, and they are potentially useful for obtaining accurate values of formation parameters from well test data. We also show that the inverse problems of estimating parameters from well data are well-posed, i.e., that parameter values obtained are unique and depend continuously on the data

Geothermal injection monitoring with dc resistivity methods

Injection into an idealized geothermal reservoir is considered, assuming that the injected water differs in temperature and salinity from in-place fluids. Changes in formation resistivity resulting from temperature and salinity variations are evaluated, and numerical simulation methods are used to predict effects which would be observed by means of dc resistivity monitoring. The resistivity calculations were performed using a three-dimensional computer code to simulate results from two different resistivity arrays, a dipole-dipole array and a downhole-surface array. Calculations show that the dipole-dipole method is relatively insensitive to changes due to injection , but downhole-surface measurements are very sensitive. From the simulated downhole-surface measurements a bell-shaped curve for resistivity change is obtained, from which the position of the chemical front may be approximately determined. Resistivity changes from temperature variations are rather small and probably cannot be detected in field measurements. Resistivity measurements are more than twice as sensitive when injected water is more saline than the in-situ reservoir fluid. This suggests that it may be easier to monitor the location of injected water if geothermal brine is reinjected rather than fresher water

System-level modeling for geological storage of CO2

One way to reduce the effects of anthropogenic greenhousegases on climate is to inject carbon dioxide (CO2) from industrialsources into deep geological formations such as brine formations ordepleted oil or gas reservoirs. Research has and is being conducted toimprove understanding of factors affecting particular aspects ofgeological CO2 storage, such as performance, capacity, and health, safetyand environmental (HSE) issues, as well as to lower the cost of CO2capture and related processes. However, there has been less emphasis todate on system-level analyses of geological CO2 storage that considergeological, economic, and environmental issues by linking detailedrepresentations of engineering components and associated economic models.The objective of this study is to develop a system-level model forgeological CO2 storage, including CO2 capture and separation,compression, pipeline transportation to the storage site, and CO2injection. Within our system model we are incorporating detailedreservoir simulations of CO2 injection and potential leakage withassociated HSE effects. The platform of the system-level modelingisGoldSim [GoldSim, 2006]. The application of the system model is focusedon evaluating the feasibility of carbon sequestration with enhanced gasrecovery (CSEGR) in the Rio Vista region of California. The reservoirsimulations are performed using a special module of the TOUGH2 simulator,EOS7C, for multicomponent gas mixtures of methane and CO2 or methane andnitrogen. Using this approach, the economic benefits of enhanced gasrecovery can be directly weighed against the costs, risks, and benefitsof CO2 injection

Merger Externalities in Oligopolistic Markets

The spatial variability of layer-scale hydrogeologic properties of the unsaturated zone (UZ) at Yucca Mountain, Nevada, is investigated using inverse modeling. The thick UZ is grouped into five hydrostratigraphic units and further into 35 hydrogeologic layers. For each layer, lateral variability is represented by the variations in calibrated values of layer-scale properties at different individual deep boreholes. In the calibration model, matrix and fracture properties are calibrated for the one-dimensional vertical column at each individual borehole using the ITOUGH2 code. The objective function is the summation of the weighted misfits between the ambient unsaturated flow (represented by measured state variables: water saturation, water potential, and pneumatic pressure) and the simulated one in the one-dimensional flow system. The objective function also includes the weighted misfits between the calibrated properties and their prior information. Layer-scale state variables and prior rock properties are obtained from their core-scale measurements. Because of limited data, the lateral variability of three most sensitive properties (matrix permeability, matrix of the van Genuchten characterization, and fracture permeability) is calibrated, while all other properties are fixed at their calibrated layer-averaged values. Considerable lateral variability of hydrogeologic properties is obtained. For example, the lateral variability of is two to three orders of magnitude and that of and is one order of magnitude. The effect of lateral variability on site-scale flow and transport will be investigated in a future study