3,306 research outputs found

    HELPING NEEDY COUNTRIES DEVELOP THEIR AGRICULTURAL RESOURCES

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    International Development,

    Survey- and fishery-derived estimates of Pacific cod (Gadus macrocephalus) biomass: implications for strategies to reduce interactions between groundfish fisheries and Steller sea lions (Eumetopias jubatus)

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    Survey- and fishery-derived biomass estimates have indicated that the harvest indices for Pacific cod (Gadus macrocephalus) within a portion of Steller sea lion (Eumetopias jubatus) critical habitat in February and March 2001 were five to 16 times greater than the annual rate for the entire Bering Sea-Aleutian Islands stock. A bottom trawl survey yielded a cod biomass estimate of 49,032 metric tons (t) for the entire area surveyed, of which less than half (23,329 t) was located within the area used primarily by the commercial fishery, which caught 11,631 t of Pacific cod. Leslie depletion analyses of fishery data yielded biomass estimates of approximately 14,500 t (95% confidence intervals of approximately 9,000–25,000 t), which are within the 95% confidence interval on the fished area survey estimate (12,846–33,812 t). These data indicate that Leslie analyses may be useful in estimating local fish biomass and harvest indices for certain marine fisheries that are well constrained spatially and relatively short in duration (weeks). In addition, fishery effects on prey availability within the time and space scales relevant to foraging sea lions may be much greater than the effects indicated by annual harvest rates estimated from stock assessments averaged across the range of the target spe

    Perils of the High and Low Roads: Employment Relations in the United States and Germany

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    [Excerpt] The U.S. crisis is characterized by growing income inequality, a shrinking safety net, and the decline of worker representation. Like the German crisis, it is caused in part by intensified global competition. Unlike in Germany, problems in the United States have also been exacerbated by deregulation, short-term horizons (e.g., quarterly reports to shareholders), and the decline of the labor movement. Both Germany and the United States, however, have substantial political, economic, and social resources to use in solving their problems. The contemporary crises do not appear for either of these countries to foreshadow a major collapse like that of the Great Depression. We are confident that actors in Germany and the United States can and will pursue reforms, including policy innovations and negotiation. In so doing, we suggest that these societies—the two strongest western economies—have a great deal to learn from each other and from their common experience in the global economy. They do not need, and are unlikely to get, convergence. Yet, each could benefit significantly by adopting elements and aspects of the other\u27s institutions, practices, and policies. In this chapter, the focus is on employment relations, which we believe are central to the broader economic and social problems in each society. We consider the following two interrelated questions. First, exactly how do the internal and external pressures on employment relations emerge in each country? Second, in what tangible forms do these pressures appear on the ground, where labor and business (and, more indirectly, other political, social, and economic actors) interact to perpetuate, alter, or scrap certain modes of production, including service delivery, work organization, and negotiation

    Toward more environmentally resistant gas turbines: Progress in NASA-Lewis programs

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    A wide range of programs are being conducted for improving the environmental resistance to oxidation and hot corrosion of gas turbine and power system materials. They range from fundamental efforts to delineate attack mechanisms, allow attack modeling and permit life prediction, to more applied efforts to develop potentially more resistant alloys and coatings. Oxidation life prediction efforts have resulted in a computer program which provides an initial method for predicting long time metal loss using short time oxidation data by means of a paralinear attack model. Efforts in alloy development have centered on oxide-dispersion strengthened alloys based on the Ni-Cr-Al system. Compositions have been identified which are compromises between oxidation and thermal fatigue resistance. Fundamental studies of hot corrosion mechanisms include thermodynamic studies of sodium sulfate formation during turbine combustion. Information concerning species formed during the vaporization of Na2SO4 has been developed using high temperature mass spectrometry

    Temperature equilibration in a fully ionized plasma: electron-ion mass ratio effects

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    Brown, Preston, and Singleton (BPS) produced an analytic calculation for energy exchange processes for a weakly to moderately coupled plasma: the electron-ion temperature equilibration rate and the charged particle stopping power. These precise calculations are accurate to leading and next-to-leading order in the plasma coupling parameter, and to all orders for two-body quantum scattering within the plasma. Classical molecular dynamics can provide another approach that can be rigorously implemented. It is therefore useful to compare the predictions from these two methods, particularly since the former is theoretically based and the latter numerically. An agreement would provide both confidence in our theoretical machinery and in the reliability of the computer simulations. The comparisons can be made cleanly in the purely classical regime, thereby avoiding the arbitrariness associated with constructing effective potentials to mock up quantum effects. We present here the classical limit of the general result for the temperature equilibration rate presented in BPS. We examine the validity of the m_electron/m_ion --> 0 limit used in BPS to obtain a very simple analytic evaluation of the long-distance, collective effects in the background plasma.Comment: 14 pages, 4 figures, small change in titl

    Nicral ternary alloy having improved cyclic oxidation resistance

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    NiCrAl alloys are improved by the addition of zirconium. These alloys are in the Beta or gamma/gamma' + Beta region of the ternary system. Zirconium is added in a very low amount between 0.06 and 0.20 weight percent. There is a narrow optimum zirconium level at the low value of 0.13 weight percent. Maximum resistance to cyclic oxidation is achieved when the zirconium addition is at the optimum value
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