Digital simulation error curves for a spring-mass-damper system

Plotting digital simulation errors for a spring-mass-damper system and using these error curves to select type of integration, feedback update method, and number of samples per cycle at resonance reduces excessive number of samples per cycle and unnecessary iterations

Managing Option Fragility

We analyze and explore option fragility, the notion that option incentives are fragile due to their non-linear payoff structure. Option incentives become weaker as options fall underwater, leading to pressures to reprice options or restore incentives through additional grants of equity-based pay. We build a detailed data set on executives' portfolios of stock and options and find that executive options are frequently underwater, even when average stock returns have been high. For example, at the height of the bull market in 1999, approximately one-third of all executive options were underwater. We find that, in contrast to the incentives provided by stock, the incentives provided by options are quite sensitive to stock price changes, especially on the downside. Overall, we find that the incentives created by all executive holdings have an elasticity with respect to stock price decreases of about 0.7, and this elasticity is larger for high-option executives and for executives with high percentages of options already underwater. The dominant mechanism through which companies manage option fragility is larger option grants following stock price declines; on average, these larger grants restore approximately 40% of the stock-price-induced incentive declines. Option repricings are far less prevalent, despite the attention they have garnered. Interestingly, we find that for positive stock returns, higher returns lead to larger option grants, which raise incentives further. Thus, option grants are largest when companies do very poorly or very well. Executive exercising behavior also affects option fragility. Since executives are much less likely to exercise options following stock price decreases, the natural declines in incentives due to exercises are attenuated on the downside, leading executives to 'manage their own incentives' in a way that augments company management of option fragility.

Teaching Graduate Trainees How to Manage Client Anger: a Comparison of Three Types of Training

The authors examined the effects of three types of training (supervisor-facilitated training, self-training, biblio-training) on 62 graduate student therapists\u27 state anxiety, self-efficacy for dealing with anger, and helping skills (i.e., reflections and immediacy) in response to videotaped vignettes of angry clients. Training overall was rated as very helpful, and trainees increased in self-efficacy for working with client anger. Supervisor-facilitated training was rated as more helpful than, and was preferred to, self-training and biblio-training; it also led to more reflection of feelings in response to clients. Results suggest that vignettes such as these might be a helpful adjunct to training once students have competency in the basic helping skills

Cathode Ray Tube Display with Cancellation of Electric Field Emissions

A cathode ray tube display having reduced electric field emissions comprising a cathode ray tube 100, an element 200 for detecting modulations in the final anode voltage of the CRT, the signal not being directly dependent on the deflection driving means 115. A matching network 205 provides phase and gain correction to the signal from element 200, amplification means 210 receives the signal from network 205 and an emission means 215 radiates a cancelling electric field dependent on the modulations detected by said element 200

Profits and Productivity

In this study we consider the linkage between productivity change and profit change. We develop an analytical framework in which profit change between one period and the next is decomposed into three sources: (i) a productivity change effect (which includes a technical change effect and an operating efficiency effect), (ii) an activity effect (which includes a product mix effect, a resource mix effect and a scale effect), and (iii) a price effect. We then show how to quantify the contribution of each effect, using only observed prices and quantities of products and resources in the two periods. We illustrate our analytical decomposition of profit change with an empirical application to Spanish banking during the period 1987 - 1994.Profits, Productivity

Social protection programs and employment: The case of Mexico’s “Seguro Popular” program

Mexico created Seguro Popular in 2002 with the goal of providing free or subsidized health insurance coverage to 47 million uninsured people by the year 2013. Only individuals lacking the social security protections granted to all formal sector workers and their families are eligible. Hence, one unintended consequence of the program could be an increase in the size of the informal sector. The introduction of the Seguro Popular program was conducted in stages, across municipalities and time. We exploit this variation and implement a differences-in-differences approach in order to identify the causal effect of the program in formal employment outcomes. We analyze the effect of Seguro Popular using 33 large and relatively rich cities from labor force surveys conducted from 2001 to 2004. In order to measure the effect for poorer municipalities, we also use the individual-level Oportunidades dataset that covers 136 municipalities from 2002 to 2004. We find little evidence of any correlation between Seguro Popular and the decision of workers to be employed in the formal or informal sector. One possible explanation of our findings is the low enrollment of the Seguro Popular program during the period we study. We provide suggestive evidence from the 33 cities that the result holds for the 2005 to 2006 period as well. We conclude that the recent increase in informal employment in Mexico is due to other causes.Mexico, informality, employment

Chance-Constrained Efficiency Analysis

Data envelopment analysis (DEA) is extended to the case of stochastic inputs and outputs through the use of chance-constrained programming. The chance-constrained envelope envelops a given set of observations "most of the time." We show that the chance-constrained enveloping process leads to the definition of a conventional (certainty-equivalent) efficiency ratio (a ratio between weighted outputs and weighted inputs). Furthermore, extending the concept of Pareto and Koopmans efficiency to the case of chance-constrained dominance (to be defined), we establish the identity of the following two chance-constrained efficiency concepts: (i) the chance constrained DEA efficiency measure of a particular output-input point is unity, and all chance-constraints are binding; (ii) the point is efficient in the sense Pareto and Koopmans. Finally we discuss the implications of our approach for econometric frontier analysis.IC2 Institut