The Evolution of Knowledge and the Dynamics of an Industry Network

The paper moves a step forward in the direction of establishing a connection between the structure and evolution of knowledge bases and the structure and evolution of organizational forms in innovative activities in a science-intensive industry. The paper has an explicit focus on the dynamics of the network of collaborative agreements in R&D in the pharma/biotech industry after the “molecular biology revolution”. Using a comprehensive dataset, built by the authors integrating several sources in the industry, the dynamics of the network over time is extensively analyzed. With regards to network structure, it is found that, while the size of the network increases over time due to net flows of entry, its topological properties remain relatively unchanged. The evolution of the network has occurred without relevant deformations in the core-periphery profile. With regards to age-dependent propensity to collaborate, the paper finds that the extent of inter-generational collaboration is much more significant than intra-generational collaboration. In addition, the propensity of firms of a given generation to enter into collaboration with firms of a different generation increases with the distance between the two, while the total number of intra-generational collaborations decreases over time and, moreover, tends to decrease for most recent generations. In the paper a unitary and coherent explanation of the evidence is developed, coming to reveal the existence of a striking isomorphism between structural properties of the dynamics of knowledge and of the evolution of network structure. This revised version was published online in July 2006 with corrections to the Cover Date.     

The British Docks: A Test of Alternative Models of Wage and Employment Determination

In this paper we compare two well-known models of union bargaining: labour demand and efficient bargains. We use data on the British docks which belonged to the national Dock Labour Board, abolished in 1989. The docks industry is particularly well-suited for a test of the competing models: in fact it had a long tradition of union bargaining on manning levels and, at the same time, it experienced a long-run decline in employment. Also, jobless dockers were granted some form of unemployment compensation. The institutional features of the industry allow to test a strong version of the efficient bargain model, where the union equates the utility of those who work and those who do not. Our evidence supports the strong efficiency hypothesis: employment depends only on the opportunity cost of working. The secular decline in employment in the industry is explained mainly by technological progress, i.e. the introduction of containers.     

The internal relocation premium: are migrants positively or negatively selected? Evidence from Italy

This paper analyzes the wage returns from internal migration for recent graduates in Italy. We employ a switching regression model that accounts for the endogeneity of the individual's choice to relocate to get a job after graduation: the omission of this selection decision can lead to biased estimates, as there is potential correlation between earnings and unobserved traits, exerting an influence on the decision to migrate. The empirical results sustain the appropriateness of the estimation technique and show that there is a significant pay gap between migrants and non-migrants; migrants seem to be positively selected and the migration premium is downward biased through OLS estimates. The endogeneity of migration shows up both as a negative intercept effect and as a positive slope effect, the second being larger than the first: bad knowledge of the local labor market and financial constraints lead migrants to accept a low basic wage but, due to relevant returns to their characteristics, they finally obtain a higher wage than the others.     

Comparing aggregate and disaggregate forecasts of first order moving average models

This paper compares the performance of “aggregate” and “disaggregate” predictors in forecasting contemporaneously aggregated vector MA(1) processes. The necessary and sufficient condition for the equality of mean squared errors associated with the two competing predictors is provided in the bivariate MA(1) case. Furthermore, it is argued that the condition of equality of predictors as stated by Lütkepohl (Forecasting aggregated vector ARMA processes, Springer, Berlin, 1987) is only sufficient (not necessary) for the equality of mean squared errors. Finally, it is shown that the equality of forecasting accuracy for the two predictors can be achieved using specific assumptions on the parameters of the vector MA(1) structure.     

AN EXACT CONDITIONAL TEST FOR COVARIANCE SELECTION MODELS

An exact conditional test is developed for testing the absence of an edge in a graphical covariance selection model and is shown to be equivalent to a test based on the partial correlation coefficient. An example is given.     

Choice and circumstance: Qualitative insights into contemporary childlessness in Australia

Using data from in-depth interviews with 115 women, men and couples in eastern Australia for whom family formation was a recent, current or imminent future issue, this article explores contemporary childlessness among those physically able to have children. It differentiates between those childless by choice and by circumstance, and among other themes highlights (i) the role preservation of lifestyle appears to play as a motive for deliberate childlessness following development of a life course through early adulthood that both generates lifestyle aspirations and often places parenthood on the backburner until after age 30, and (ii) the roles difficulty forming suitable relationships, women’s desire for meaningful careers, and male involvement in family formation decisions play in bringing about childlessness by circumstance.     

The social “R & D” paradigm in child and youth services: Building knowledge convivially

Adaptation of agricultural and industrial research and development models offers new methods for bridging the worlds of research and practice in child and youth services. Social R & D methodologies provide effective means for generating new social technologies because they are product oriented and use a wide array of traditional and nontraditional data sources. This article discusses one social R & D paradigm—Developmental Research and Utilization. Permanency planning and community support systems research are used to illustrate the past and potential application of this methodology to the field of child and youth services.     

"He is everything": religion's role in the lives of immigrant youth

Using emergent theme analysis of qualitative interview data in combination with quantitative survey data, the role of religion in the lives of immigrant youth was explored. Latino, Haitian, and Chinese teenagers described, in their own rich words, the significance of religion to them; their responses are reflected in themes that point to the potential protective role of religion for some immigrant groups.     

Why Do They Start It? Explaining Reported Early-Teen Sexual Activity

This paper seeks an account of why young teens initiate consensual sexual activity. It does so by constructing statistical models aimed at distinguishing those who report having initiated sexual activity from those who have not in four samples of eighth graders from an Upstate New York county. Theoretical selection of the model variables is guided by insights from problem syndrome, control and differential association theories. From our findings we conclude the following: (1) Risk behaviors foreseen by the problem syndrome approach, including having used marijuana and having been drunk, are significant, powerful predictors of early-teen sexual activity. (2) The social setting of consensual sexual activity differs by sex at the eighth grade level. For example, having a boyfriend is a more consistent, powerful predictor variable for girls than is having a girlfriend for boys and there is evidence to support the hypothesis that boys initiate sexual activity in the context of status-seeking while girls are more likely to do so as a way of attaining approval. (3) Our findings do not give clear primacy to parents or peers as an influence on early-teen consensual sexual activity. Both control theory, usually associated with parental-influence variables, and differential association theory, usually associated with peer-influence variables, receive support. (4) The results of the research spanning a 2-year period of intensive community antiteen-pregnancy efforts by a Zero Adolescent Pregnancy (ZAP) campaign are consistent with the conclusion that such a multifaceted approach might help lower early-teen initiation of sexual activity.