Who Will Benefit from ESOPs?

[Excerpt] In the past decade, the number of worker-owned firms or ESOPs (Employee Stock Ownership Plans) has been growing geometrically. The national law granting tax incentives to ESOPs was passed in 1975, and since then several other pieces of legislation promoting employee ownership have passed at the federal level and in eight state legislatures. As a result of the technical assistance and industrial revenue bonds that some states now provide for ESOP development, and as a result of demonstrable tax, productivity, labor relations and even marketing advantages, business has taken note of the ESOP option. Several thousand ESOPs have started and scores of reports on employee ownership have appeared in the popular press and in business and trade publications

A Switching Fluid Limit of a Stochastic Network Under a State-Space-Collapse Inducing Control with Chattering

Routing mechanisms for stochastic networks are often designed to produce state space collapse (SSC) in a heavy-traffic limit, i.e., to confine the limiting process to a lower-dimensional subset of its full state space. In a fluid limit, a control producing asymptotic SSC corresponds to an ideal sliding mode control that forces the fluid trajectories to a lower-dimensional sliding manifold. Within deterministic dynamical systems theory, it is well known that sliding-mode controls can cause the system to chatter back and forth along the sliding manifold due to delays in activation of the control. For the prelimit stochastic system, chattering implies fluid-scaled fluctuations that are larger than typical stochastic fluctuations. In this paper we show that chattering can occur in the fluid limit of a controlled stochastic network when inappropriate control parameters are used. The model has two large service pools operating under the fixed-queue-ratio with activation and release thresholds (FQR-ART) overload control which we proposed in a recent paper. We now show that, if the control parameters are not chosen properly, then delays in activating and releasing the control can cause chattering with large oscillations in the fluid limit. In turn, these fluid-scaled fluctuations lead to severe congestion, even when the arrival rates are smaller than the potential total service rate in the system, a phenomenon referred to as congestion collapse. We show that the fluid limit can be a bi-stable switching system possessing a unique nontrivial periodic equilibrium, in addition to a unique stationary point

Heavy-traffic limits for waiting times in many-server queues with abandonment

We establish heavy-traffic stochastic-process limits for waiting times in many-server queues with customer abandonment. If the system is asymptotically critically loaded, as in the quality-and-efficiency-driven (QED) regime, then a bounding argument shows that the abandonment does not affect waiting-time processes. If instead the system is overloaded, as in the efficiency-driven (ED) regime, following Mandelbaum et al. [Proceedings of the Thirty-Seventh Annual Allerton Conference on Communication, Control and Computing (1999) 1095--1104], we treat customer abandonment by studying the limiting behavior of the queueing models with arrivals turned off at some time $t$. Then, the waiting time of an infinitely patient customer arriving at time $t$ is the additional time it takes for the queue to empty. To prove stochastic-process limits for virtual waiting times, we establish a two-parameter version of Puhalskii's invariance principle for first passage times. That, in turn, involves proving that two-parameter versions of the composition and inverse mappings appropriately preserve convergence.Comment: Published in at http://dx.doi.org/10.1214/09-AAP606 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Confronting Wartime Sexual Violence: Public Support for Survivors in Bosnia

Existing research on conflict-related sexual violence focuses on the motivations of perpetrators and effects on survivors. What remains less clear is how postconflict societies respond to the hardships survivors face. In survey experiments in Bosnia, we examine public support for financial aid, legal aid, and public recognition for survivors. First, we find a persistent ethnocentric view of sexual violence, where respondents are less supportive when the perpetrator is identified as co-ethnic and survivors are perceived as out-groups. Second, respondents are less supportive of male survivors than female survivors, which we attribute to social stigmas surrounding same-gender sexual activity. Consistent with our argument, those who are intolerant of homosexuality are especially averse to providing aid to male survivors. This study points to the long-term challenges survivors face due to ethnic divisions and social stigmatization from sexual violence

Beyond Keeping the Peace: Can Peacekeepers Reduce Ethnic Divisions After Violence?

Existing research suggests that international peacekeeping contributes to conflict resolution and helps sustain peace, often in locations with hostile ethnic divisions. However, it is unclear whether the presence of peacekeepers actually reduces underlying ethnocentric views and parochial behaviors that sustain those divisions. We examine the effects of NATO peacekeeper deployments on ethnocentrism in postwar Bosnia. While peacekeepers were not randomly deployed in Bosnia, we find that highly ethnocentric attitudes were common across Bosnia at the onset of peacekeeper deployments, reducing endogeneity concerns. To measure ethnocentrism, we employ a variety of survey instruments as well as a behavioral experiment (the dictator game) with ethnic treatments across time. We find that regions with peacekeepers exhibit lower levels of ethnocentrism in comparison to regions without peacekeepers, and this effect persists even after peacekeepers have departed. The peacekeeping effect is also robust to a sub-sample of ethnic Bosnian Serbs, suggesting that peacekeeper deployments can have positive effects on diminishing ethnocentrism, even when local communities are especially hostile to their presence. Our results speak to the potential long-term role of peacekeepers in reducing tensions among groups in conflict

Martingale proofs of many-server heavy-traffic limits for Markovian queues

This is an expository review paper illustrating the ``martingale method'' for proving many-server heavy-traffic stochastic-process limits for queueing models, supporting diffusion-process approximations. Careful treatment is given to an elementary model -- the classical infinite-server model $M/M/\infty$, but models with finitely many servers and customer abandonment are also treated. The Markovian stochastic process representing the number of customers in the system is constructed in terms of rate-1 Poisson processes in two ways: (i) through random time changes and (ii) through random thinnings. Associated martingale representations are obtained for these constructions by applying, respectively: (i) optional stopping theorems where the random time changes are the stopping times and (ii) the integration theorem associated with random thinning of a counting process. Convergence to the diffusion process limit for the appropriate sequence of scaled queueing processes is obtained by applying the continuous mapping theorem. A key FCLT and a key FWLLN in this framework are established both with and without applying martingales.Comment: Published in at http://dx.doi.org/10.1214/06-PS091 the Probability Surveys (http://www.i-journals.org/ps/) by the Institute of Mathematical Statistics (http://www.imstat.org

High gradient directional solidification furnace

A high gradient directional solidification furnace is disclosed which includes eight thermal zones throughout the length of the furnace. In the hot end of the furnace, furnace elements provide desired temperatures. These elements include Nichrome wire received in a grooved tube which is encapsulated y an outer alumina core. A booster heater is provided in the hot end of the furnace which includes toroidal tungsten/rhenium wire which has a capacity to put heat quickly into the furnace. An adiabatic zone is provided by an insulation barrier to separate the hot end of the furnace from the cold end. The old end of the furnace is defined by additional heating elements. A heat transfer plate provides a means by which heat may be extracted from the furnace and conducted away through liquid cooled jackets. By varying the input of heat via the booster heater and output of heat via the heat transfer plate, a desired thermal gradient profile may be provided

Battery and cell testing at NASA. Marshall Space Flight Center

An overview covering the ten cell/battery tests ongoing at MSFC are presented. The presentation is not intended to give specific test results on any test. The purpose and related program that applies to each test is acknowledged. Except for the Combined Release and Radiation Effects Satellite (CRRES), all are energy-stored and retrieval devices at low earth orbit (LEO) cycles

General purpose rocket furnace

A multipurpose furnace for space vehicles used for material processing experiments in an outer space environment is described. The furnace contains three separate cavities designed to process samples of the widest possible range of materials and thermal requirements. Each cavity contains three heating elements capable of independent function under the direction of an automatic and programmable control system. A heat removable mechanism is also provided for each cavity which operates in conjunction with the control system for establishing an isothermally heated cavity or a wide range of thermal gradients and cool down rates. A monitoring system compatible with the rocket telemetry provides furnace performance and sample growth rate data throughout the processing cycle