498 research outputs found

    The Costs of Defined Benefit Pension Plans and Firm Adjustments

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    [Excerpt] While it is obvious that the costs of term life insurance vary directly with age, it is less obvious how employers\u27 contributions to pension funds, which comprise a major share of nonwage compensation, vary. As such, we focus in this paper on the most common variant of pension plans and demonstrate how an employer\u27s cost of fully funding a plan varies with the age and service characteristics of his work force. This cost, as a percent of annual salary, is seen to increase with employees\u27 ages and, in some cases, years of service. This variation has important implications for the level and shape of life-cycle earnings profiles, for labor turnover, and for the likely impact of pension reform legislation, such as the Employees Retirement Income Security Act of 1974 (ERISA), on the well-being of workers. These implications are discussed in this paper

    Social network analysis:Foundations and frontiers on advantage

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    We provide an overview of social network analysis focusing on network advantage as a lens that touches on much of the area. For reasons of good data and abundant research, we draw heavily on studies of people in organizations. Advantage is traced to network structure as a proxy for the distribution of variably sticky information in a population. The network around a person indicates the person's access and control in the distribution. Advantage is a function of information breadth, timing, and arbitrage. Advantage is manifest in higher odds of proposing good ideas, more positive evaluations and recognition, higher compensation, and faster promotions. We discuss frontiers of advantage contingent on personality, cognition, embeddedness, and dynamics.</p

    Helically corrugated waveguides for compression of frequency swept microwave pulses

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    Short pulse high power microwave radiation can be used for time of flight diagnostic measurements in plasmas, e.g. density profiles by reflectometry. A three-fold helical corrugation of the inner surface of a waveguide synthesises eigenwaves having useful dispersive properties by combining two distinct counter-rotating modes of a corresponding circular waveguide. The dispersion may be tailored to the requirements of an application by adjusting the amplitude and period of the corrugations. Such dispersive properties have proven useful in broadband radiation amplifiers, or to achieve passive compression of smoothly frequency modulated microwave pulses. The paper presents results of experiments using a solid state source to produce an optimised frequency-chirped input pulse and amplified by a high power Travelling Wave Tube Amplifier (TWTA). The waveforms of the input and output microwave signals were captured on a UHF Digital Storage Oscilloscope. The results demonstrated at 5.7kW input power levels that X-band radiation pulses of 67ns duration with 5% frequency modulation can be compressed into a 2.8ns pulse having 12 times higher peak power, whilst retaining 50% of the energy in the input signal. The technique offers great potential for scaling to higher frequencies and power levels

    A genetically informed cross-lagged analysis of autistic-like traits and affective problems in early childhood

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    A genetically informed cross-lagged model was applied to twin data to explore etiological links between autistic-like traits and affective problems in early childhood. The sample comprised 310 same-sex twin pairs (143 monozygotic and 167 dizygotic; 53% male). Autistic-like traits and affective problems were assessed at ages 2 and 3 using parent ratings. Both constructs were related within and across age (r = .30-.53) and showed moderate stability (r = .45-.54). Autistic-like traits and affective problems showed genetic and environmental influences at both ages. Whereas at age 2, the covariance between autistic-like traits and affective problems was entirely due to environmental influences (shared and nonshared), at age 3, genetic factors also contributed to the covariance between constructs. The stability paths, but not the cross-lagged paths, were significant, indicating that there is stability in both autistic-like traits and affective problems but they do not mutually influence each other across age. Stability effects were due to genetic, shared, and nonshared environmental influences. Substantial novel genetic and nonshared environmental influences emerge at age 3 and suggest change in the etiology of these constructs over time. During early childhood, autistic-like traits tend to occur alongside affective problems and partly overlapping genetic and environmental influences explain this association

    Measuring personal networks and their relationship with scientific production

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    The analysis of social networks has remained a crucial and yet understudied aspect of the efforts to measure Triple Helix linkages. The Triple Helix model aims to explain, among other aspects of knowledge-based societies, ¿the current research system in its social context. This paper develops a novel approach to study the research system from the perspective of the individual, through the analysis of the relationships among researchers, and between them and other social actors. We develop a new set of techniques and show how they can be applied to the study of a specific case (a group of academics within a university department). We analyse their informal social networks and show how a relationship exists between the characteristics of an individual¿s network of social links and his or her research output

    Social capital: a roadmap of theoretical and empirical contributions and limitations

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    The general idea of social capital is that relationships matter. In this sense, the trust, cooperation and reciprocity involved in these relationships can have a positive impact on the wealth of society by reducing transaction costs, facilitating collective actions, and lowering opportunistic behavior. This work sheds light on the different theoretical and empirical problems that a scholar is likely to face in dealing with social capital research and analysis. We propose a critical roadmap of the social capital theories and applications for a general audience, nonusers included, with particular attention to the works of political and social economists. We provide a critical debate on the different definitions and measures produced, the theoretical frameworks developed, and the empirical techniques adopted so far in the analysis of the impact of social capital on socio-economic outcomes. We turn to the limitations of these techniques and suggest some basic strategies to reduce the magnitude of these limitations
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