7,026 research outputs found

    Andrew Lenard: A Mystery Unraveled

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    The theory of bi-Hamiltonian systems has its roots in what is commonly referred to as the "Lenard recursion formula". The story about the discovery of the formula told by Andrew Lenard is the subject of this article.Comment: Published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

    Comparing Caddo and Coles Creek Pottery Using Petrographic Analysis

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    Pottery classified as “Coles Creek Incised” is common both to the earliest Caddo sites along the Red River and to contemporary sites in the Lower Mississippi Valley. Although it often is suggested that Coles Creek pottery from the two regions can be distinguished by differences in paste, no detailed comparative studies have been carried out. An initial attempt to identify variation through the use of petrographic analysis was carried out by comparing 50 samples drawn from sites in northwest and central Louisiana. Although no sharp dichotomy was noted between the regions, the study identified distinctions that support the notion that most Coles Creek pottery was made locally and different technological traditions may be represented

    Variability in the extreme helium star LSS 5121

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    We report a photometric and spectroscopic study of the hot extreme helium star LSS 5121. We found photometric variability, but no period was evident in its periodogram. This is consistent with the previous proposal, based on spectral line variations, that LSS 5121 is a non-radial pulsator similar to other hot extreme helium stars.Comment: 5 pages, 6 figure

    Explaining US Immigration 1971-1998

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    In this paper we develop and estimate a model to explain the level and source country composition of immigration to the United States since the early 1970s. The model incorporates ratios to the US of source country income and education, and demographic structure, as well as relative inequality as suggested by the Roy model applied to migrant selection. In addition we incorporate the 'friends and relatives effect' as reflected in the stock of previous immigrants and a variety of variables representing different dimensions of the immigration quotas set by policy. We estimate our immigration model on a panel of 81 source countries for the years 1971 to 1998. The results strongly support the influence of economic and demographic variables and geographic characteristics as well as policy variables. We use the results to shed light on the factors that influenced the composition of US immigration by source region. And we provide a further check on its plausibility by simulating the effects of the key changes in immigration policy since the late 1970s.

    United States Pollution Control Laws

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    The environmental assessment process established by NEPA has been a success and was a step forward on the path of integrating environmental and economic policy. The national pollution abatement laws that were adopted in the decade after NEPA, however, operate in a very different fashion. They, too, have been very successful in a number of important respects, but have achieved less than we had hoped for because of certain flaws in their design. To analyze these laws for us, I would like to introduce another colleague, Professor Jeffery Miller, who has also travelled in Argentina. In fact, Professor Miller conducted workshops for the delegates at the Constitutional Convention who drafted the amendments to the Constitution of Argentina. He is familiar with the legal systems in Argentina and we are delighted that he could be with us today

    Generations in the Workplace: Similarities and Differences.

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    Occurrences of four generations working side by side are not unusual. The four generations include Traditionalist, Baby Boomers, Generation X, and Generation Y. Members of each generation have views and opinions about their work ethic and their definition of loyalty to the organization. Hiring managers will need to know characteristics of each generation. This knowledge will enable the hiring managers to place the applicant in certain positions within their organizations. By matching applicants with the correct work positions, employees are able to use their skills and abilities to be productive and to establish measurable goals for themselves and their departments. Productive work enables the employees to work individually and as a team member. The research has shown that each generation has its own strengths and weakness. Members of the older generations show characteristics that accommodate customer service and loyalty to an organization. Members of the younger generations have the technical knowledge and the ability to train others in order to use this technology to the benefit of the organization
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