REQUIREMENTS PLANNING FOR CONTROL OF INFORMATION RESOURCES

Producing reports assembled from files, records, and raw data is a major function of the computer in modern organizations. Transaction processing, records management, file organization, and data-base management are aspects of the information production function that have received a good deal of attention. But planning, scheduling, and controlling the production of information products have been neglected. For complex applications involving assembly of reports from multilevel information sources, the requirements planning model is suggested as an effective alternative to present methods. Thus, our suggestion is that the computer be used to plan, schedule, and control computer production of information products. Presently available material requirements planning software may be employed with minor modifications that depend on the given information system characteristics. In this paper an example of requirements planning as applied to production of information in a satellite control system is presented.     

The Gradient of Immigrant Age‐at‐Arrival Effects on Socioeconomic Outcomes in the U.S.1

A young age at arrival is believed to be an important predictor of adult immigrant achievement, but there is no consensus on what age(s) at arrival is pivotal/crucial/critical. The 2000 census reports exact years of arrival and age providing us the opportunity to test different formulations for age‐at‐arrival effects for several different socioeconomic outcomes. We focus on the experiences of Mexican immigrants to the U.S. in this study. Our results indicate That the effect of early arrival is much greater for English proficiency than other outcomes and bears significantly on most, not all, attainments. There is little evidence at any age of a sharp discontinuity demarcating a 1.5 generation from older immigrants and, in fact, a series of classifications or a continuous measurement of age at arrival may be preferred in some cases. Guidelines are offered for the most appropriate formulation of age at arrival under different contexts.     

Intergenerational Mobility of the Mexican‐Origin Population in California and Texas Relative to a Changing Regional Mainstream

We combine two approaches to gauge the achievements of the Mexican‐origin second generation: one the intergenerational progress between immigrant parents and children, the other the gap between the second generation and non‐Latino whites. We measure advancement of the Mexican‐origin second generation using a suite of census‐derived outcomes applied to immigrant parents in 1980 and grown children in 2005, as observed in California and Texas. Patterns of second‐generation upward mobility are similar in the two states, with important differences across outcome indicators. Assessments are less favorable for men than women, especially in Texas. We compare Mexican‐Americans to a non‐Latino white reference group, as do most assimilation studies. However, we separate the reference group into those born in the same state as the second generation and those who have migrated in. We find that selective in‐migration of more highly‐educated whites has raised the bar on some, not all, measures of attainment. This poses a challenge to studies of assimilation that do not compare grown‐children to their fellow natives of a state. Our model of greater temporal and regional specificity has broad applicability to studies guided by all theories of immigrant assimilation, integration and advancement.     

Gypsy students in the UK: the impact of ‘mobility’ on education

This paper argues that Gypsy students in primary and secondary education in the UK are marginalised because of ambiguous understandings of their ‘mobility’. Drawing on research conducted on the south coast of England, it examines Gypsy families’ experiences of education. Despite often describing their identity in relation to travelling or mobility, few families’ lifestyles were characterised by actual movement or nomadism. Teachers and educationalists meanwhile cite the need to deliver a ‘mobile’ rather than a ‘sedentary’ education for Gypsy students. The Department for Communities and Local Government recently defined Gypsy ethnicity in direct relation to a nomadic lifestyle. This is problematic as the association between Gypsy ethnicity and nomadism is itself questionable and may be better understood in more nuanced terms reflecting the relationship between identity and ‘mobility’. This paper argues that ‘mobility’ is understood to define Gypsy difference in a way that excludes students.     

Strict Positive Definiteness of a Product of Covariance Functions

Positive definiteness represents an admissibility condition for a function to be a covariance. Nevertheless, the more restricted condition of strict positive definiteness has received attention in literature, especially in spatial statistics, since it ensures that the kriging system has a unique solution. Most known covariance functions are isotropic but there are applications where isotropy is not appropriate, e.g., space-time covariance functions. One way to construct non-isotropic covariance functions is to use a product or a product-sum. In this article, it is given a necessary as well as a sufficient condition for a product of two covariance functions to be strictly positive definite. This result is extended to the well-known product-sum covariance model.     

Innovation Strategy,Human Resource Policy,and Firms' Revenue Growth: The Roles of Environmental Uncertainty and Innovation Performance*

This study investigates the interactions of innovation strategy execution and innovation‐focused human resource (HR) policy adoption on innovation performance and revenue growth. In addition, we investigate the moderating role of environmental uncertainty on the effects of innovation strategy execution and innovation‐focused HR policy on innovation performance. Results show that the interaction of innovation strategy execution and innovation‐focused HR policy is positively related to innovation performance. Results also show that environmental uncertainty positively moderates the innovation strategy execution–innovation performance relationship. Finally, innovation performance mediates the interaction of innovation strategy execution and environmental uncertainty on firms’ revenue growth. Implications of these findings for theory and practice are discussed.     

Migration and fertility in Puerto Rico

Abstract In an investigation based on special tabulations of the 25 per cent sample from the 1960 Census of Population for Puerto Rico, it is found that migration experience tends to be associated with fertility for various marital statuses, including consensual unions, and for rural, urban and metropolitan residence. The findings cannot be attributed to variations in age composition among the various categories as age standardization and age-specificcomparisons yield similar results. However, it is also found that rural-urban and consensually-legally mated differentials in fertility cannot be accounted for by variations in the migration variables that are examined. Thus, consistently higher fertility is found for non-migrants than for migrants; for consensually mated than for legally married and for rural than for urban or metropolitan residents. With a single exception, women in consensual unions, fertility is lower for women in the San Juan metropolitan area than in the other urban areas.     

The dynamics of job creation and job destruction in Australia

This paper develops measures of job creation and job destruction (JC&D) based on the methodology initially developed by Davis and Haltiwanger (1990) and using industry employment data from the ABS Survey of Employment and Earnings (SEE), which is available on a quarterly basis between August 1983 and December 2001. It specifically examines the interaction of part‐time and full‐time employment with JC&D processes over the business cycle. Econometric analysis has been conducted to determine the time series properties of cyclical sensitivity and asymmetry. These findings are considered in the context of the likely consequences of the Howard government's Work Choices legislation.