Decentralized WIP-oriented manufacturing control (DEWIP)

DEWIP is a manufacturing control system for job shop environments aiming at achieving short and reliable lead times by establishing WIP control loops between the manufacturing work centres. The paper describes the mode of function, the setting of parameters and simulation results of the new manufacturing control system. The setting of parameters is done with the aid of the funnel model and the theory of logistic operating curves, both developed at the Institute of Production Systems at the University of Hanover. The simulation is conducted using industrial data and makes it possible to assess DEWIP with regard to lead times, WIP level, performance and schedule reliability. DEWIP is compared both with an uncontrolled process and with the manufacturing control systems Load oriented order release (LOOR), Conwip and Polca. The results suggest that DEWIP and the models employed for the setting of parameters are suitable for job shop production and therefore offer a valuable alternative to prevailing centralized manufacturing control systems.     

Nativity and Self‐Assessed Health among Pre‐Retirement Age Hispanics and Non‐Hispanic Whites1

Economic, social and familial resources are known to influence subjective health assessments. We examine the salience of nativity in determining how these resources influence self‐assessed health using a large, nationwide sample of Hispanic and non‐Hispanic white adults. The results indicate that while education, accumulated assets and marital status benefit the physical and emotional health of the native and foreign‐born, family resources and income are significant only for the native‐born. English language proficiency is a significant protective factor for both groups and is especially protective for immigrants. These surprising findings call into question previous studies stressing the positive role of the family in maintaining immigrant health.     

Causal Ordering of Basic Psychological Needs and Well-Being

What is the relationship between well-being and satisfaction of basic psychological needs overtime? The basic psychological needs theory is a subtheory of the self-determination theory that elaborates the concept of psychological needs and its relations to psychological health and well-being. The goals of this research was to establish the causal ordering between basic psychological needs and three psychological well-being indicators (subjective well-being, self-esteem and satisfaction with life), in a longitudinal study. We used a cross-lagged two-wave design. A total of 272 university students completed the questionnaire at the beginning and at the end of the semester. Relatedness at time 1 (T₁) had a positive and significant effect on all well-being indicators at time 2 (T₂); competence (T₁) had a positive and significant effect on all indicators except for self-esteem (T₂); finally, autonomy (T₁) did not have a significant effect on any of the well-being indicators (T₂). In conclusion, we confirm the causal ordering of competence and relatedness on well-being, according to the basic psychological needs subtheory. Universities, in general, and teachers, in particular, should promote relations between students and support the need of competence.     

On the Measurement of Interpersonal Trust Transfer: Proposal of Indexes

This paper investigates the measurement of trust transfer in interpersonal contexts. Despite the importance of this topic, little evidence of comparable indicators exists to fill the current gap in knowledge regarding the measurement of interpersonal transference of trust and its reciprocal. We propose a modification of the classical structure of a widely accepted experimental setting for analyzing trust (i.e. a trust game) and build two indexes for the measurement of trust transfer and its reciprocation. Several properties of these indicators are investigated to examine their robustness and accuracy for measuring the transference of interpersonal trust. Furthermore, using data from our own modified trust game, we provide an empirical examination of both indexes. The results show that the existence of a mutually known third party fosters a stronger willingness to achieve cooperative behavior in an anonymous trust game; thus, the transference of interpersonal trust works in both directions of the dyad.     

Successful innovation through inter-company networks

Companies are now investing in the new technologies of the 1990s. This article deals with the central question of why and how companies work together on technological innovation. First the author looks at the reality of technological innovation, and review reasons why companies might want to work together in this area. They then uncover the different types of collaboration involved in technological innovation. These forms are innovation networks, and they identify several success factors for innovation networks.     

Network Evening News Coverage of Environmental Risk

ABC, CBS, and NBC's carefully crafted and expensively produced evening news broadcasts devoted 1.7% of their air time to 564 stories about man-made environmental risks during the period from January 1984 to February 1986. Little relationship was found between amount of coverage and public health risk. Instead, the networks appeared to be using traditional journalistic determinants of news (timeliness, proximity, prominence, consequence, and human interest) plus the broadcast criterion of visual impact to determine the degree of coverage of risk issues. Government, industry, and citizens accounted for two-thirds of the sources cited by the networks. Experts and spokespersons for environmental advocacy groups were sparsely used as sources. Given the media's need for news pegs, acute and chronic risk stories were covered differently. Acute risk stories were reported in a clearly defined cycle, peaking on the second day with on-the-scene reports and film-clips of devastation. In keeping with a decrease in visual drama, later reports were shorter and emphasized legal and political considerations. Chronic risk coverage followed the release of new scientific, legal, or political information.     

Dose-Response Assessment of Airborne Methyl Isothiocyanate (MITC) Following a Metam Sodium Spill

A tank car derailment in northern California in 1991 spilled metam sodium into the Sacramento River, and released its breakdown product, methyl isothiocyanate (MITC), into the air. This paper describes the risk evaluation process used. Over 240 individuals reported symptoms such as eye and throat irritation, dizziness, and shortness of breath. Reference exposure levels (RELs) for 1 hr were developed for MITC and compared to exposure concentrations. Ocular irritation in cats was the most sensitive endpoint reported. The no observed adverse effect level (NOAEL), divided by an uncertainty factor (UF) of 100, produced an REL of 0.5 ppb of MITC in air to prevent discomfort. An REL to prevent disability was estimated to be 40 ppb. An REL to prevent life-threatening injury was estimated to be 150 ppb. Measured MITC levels ranged from 0.2-37 ppb and estimated peak levels ranged from 140-1600 ppb. The usefulness of RELs for emergency planning is discussed.