The Gender Gap in Top Corporate Jobs

Using the ExecuComp data set, which contains information on the five highest-paid executives in each of a large number of U.S. firms for the years 1992–97, the authors examine the gender compensation gap among high-level executives. Women, who represented about 2.5% of the sample, earned about 45% less than men. As much as 75% of this gap can be explained by the fact that women managed smaller companies and were less likely to be CEO, Chair, or company President. The unexplained gap falls to less than 5% with an allowance for the younger average age and lower average seniority of the female executives. These results do not rule out the possibility of discrimination via gender segregation or unequal promotion. Between 1992 and 1997, however, women nearly tripled their participation in the top executive ranks and also strongly improved their relative compensation, mostly by gaining representation in larger corporations

A Z_3-graded generalization of supermatrices

We introduce Z_3-graded objects which are the generalization of the more familiar Z_2-graded objects that are used in supersymmetric theories and in many models of non-commutative geometry. First, we introduce the Z_3-graded Grassmann algebra, and we use this object to construct the Z_3-matrices, which are the generalizations of the supermatrices. Then, we generalize the concepts of supertrace and superdeterminant

Scalar-Tensor gravity with system-dependent potential and its relation with Renormalization Group extended General Relativity

We show that Renormalization Group extensions of the Einstein-Hilbert action for large scale physics are not, in general, a particular case of standard Scalar-Tensor (ST) gravity. We present a new class of ST actions, in which the potential is not necessarily fixed at the action level, and show that this extended ST theory formally contains the Renormalization Group case. We also propose here a Renormalization Group scale setting identification that is explicitly covariant and valid for arbitrary relativistic fluids.Comment: 29 pages, 2 figs. v2: small changes in text and ref's. v3: further details on the relation between this work and others on the Renormalization Group. Version to appear in JCA

Differential cross sections at forward angles for hydrogen and helium particles from 62 MeV protons incident on Ni-60

Tabulated differential cross sections are presented for the production, at angles of 15, 20, 25, and 40 deg, of proton, deuteron, triton, helium-3, and alpha particles from Ni-60 bombarded by 62-MeV protons. Continuum cross sections are listed in about 1-MeV bins for energies above lower cutoffs which range from 4 to 15 MeV for the different types of exit particles. Only the integral cross section is known for a considerable energy range within each spectrum. The proton, deuteron, and alpha particle cross sections are the same in the continuum range region above the evaporation peak as those cross sections previously observed for Fe-54 and Fe-56, but the corresponding yield of tritons is higher from Ni-60 and Fe-56 than from Fe-54

Tabulated cross sections for hydrogen and helium particles produced by 61-MeV protons on Fe56

Tabulated cross sections for hydrogen and helium particles produced by 61 MeV on iron 5

Does Managed Care Change the Mission of Nonprofit Hospitals? Evidence From the Managerial Labor Market

This paper examines how the managerial labor market in nonprofit hospitals has adjusted to the negative income pressures created by HMO penetration. Using a panel of about 1500 nonprofit hospitals over the period 1992 to 1996, we find that top executive turnover increases following an increase in HMO penetration. Moreover, the increase in turnover is concentrated among the hospitals that have low levels of economic profitability and are more financially leveraged. While the link between top executive pay and for-profit performance measures is on average very weak, HMO penetration substantially tightens that link: as HMO penetration increases, top executives are compensated more for improving the profitability of their hospitals. These results are consistent with the view that HMO penetration increases the importance of for-profit performance objectives among not-for-profit hospitals. Boards appear to fire the managers that are least able to compete in the new competitive environment and reward incumbent managers more for achieving for-profit goals. Consistent with donors' belief that these changes represent a weakening of the nonprofit mission and not simply an attempt by altruistic boards to protect intergenerational equity, we find that public donations fall as HMO market share increases.

Alternate operating methods for improving the performance of a continuous stirred tank reactor

The effect of the pumping direction of an axial flow impeller, the feeding rate and the number of feed inlets on the operation of a continuously-fed stirred tank has been studied using CFD. The flow patterns generated by the up-pumping and down-pumping impeller, under both ‘typical’ and ‘intensified’ operating conditions, are compared. The effect of various tank configurations on the performance of the vessel is assessed by analysing the flow and power numbers, as well as the concentration field of a non-reactive tracer. Furthermore, the inlet feed jets are reduced using traditional jet similarity analysis and are compared with that of a typical round jet. The results show that up-pumping impellers improve circulation in the upper part of the tank and reduce shortcircuiting of the feed stream with only a small increase in power consumption. Furthermore, by using multiple feed inlets to increase the total throughput capacity, the amplitude of torque fluctuations is decreased and impeller bypassing is also decreased. The ensemble of conclusions suggest that the throughput capacity and mixing quality of a CSTR can be improved, without problems of short-circuiting, by employing up-pumping impellers coupled with multiple surface feed points

PIV measurements in an aerated tank stirred by a down- and up-pumping axial flow impeller

Liquid phase hydrodynamics in an aerated tank stirred by a down- and an up-pumping pitched blade turbine have been investigated using Particle Image Velocimetry. The effect of agitator configuration and the gas phase on the mean velocity fields and turbulent quantities in the vessel have been investigated. The global mean gas holdup has also been evaluated for the two pumping conditions. For the gas flow rate used, the presence of gas only slightly alters the liquid flow patterns produced by both the down- and up-pumping configurations and causes a general decrease in the mean liquid velocities. The turbulent kinetic energy in the impeller discharge region was not affected by the presence of gas, but in the bulk of the tank, aeration caused a decrease in this value. Global gas holdup was found to be ~36% greater for the up-pumping impeller and a large amount of gas was found to be entrained by the primary circulation loop