11,607 research outputs found

    Factorization Breaking of AdTA^T_d for polarized deuteron targets in a relativistic framework

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    We discuss the possible factorization of the tensor asymmetry AdTA^T_d measured for polarized deuteron targets within a relativistic framework. We define a reduced asymmetry and find that factorization holds only in plane wave impulse approximation and if p-waves are neglected. Our numerical results show a strong factorization breaking once final state interactions are included. We also compare the d-wave content of the wave functions with the size of the factored, reduced asymmetry and find that there is no systematic relationship of this quantity to the d-wave probability of the various wave functions

    Quark-Hadron Duality

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    Quark-hadron duality and its potential applications are discussed. We focus on theoretical efforts to model duality.Comment: Plenary Talk given at Baryons 2002, Newport News, VA, March 200

    Paleoamerican diet, migration and morphology in Brazil

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    During the early Holocene two main paleoamerican cultures thrived in Brazil: the Tradição Nordeste in the semi-desertic Sertão and the Tradição Itaparica in the high plains of the Planalto Central. Here we report on paleodietary singals of a Paleoamerican found in a third Brazilian ecological setting--a riverine shellmound, or sambaqui, located in the Atlantic forest. Most sambaquis are found along the coast. The peoples associated with them subsisted on marine resources. We are reporting a different situation from the oldest recorded riverine sambaqui, called Capelinha. Capelinha is a relatively small sambaqui established along a river 60 km from the Atlantic Ocean coast. It contained the well-preserved remains of a Paleoamerican known as Luzio dated to 9,945±235 years ago; the oldest sambaqui dweller so far. Luzio's bones were remarkably well preserved and allowed for stable isotopic analysis of diet. Although artifacts found at this riverine site show connections with the Atlantic coast, we show that he represents a population that was dependent on inland resources as opposed to marine coastal resources. After comparing Luzio's paleodietary data with that of other extant and prehistoric groups, we discuss where his group could have come from, if terrestrial diet persisted in riverine sambaquis and how Luzio fits within the discussion of the replacement of paleamerican by amerindian morphology. This study adds to the evidence that shows a greater complexity in the prehistory of the colonization of and the adaptations to the New World

    Will China Eat Our Lunch or Take us to Dinner? - Simulating the Transition Paths of the U.S., Eu, Japan and China

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    This paper develops a dynamic, life-cycle, general equilibrium model to study the interdependent demographic, fiscal, and economic transition paths of China, Japan, the U.S.,and the EU. Each of these countries/regions is entering a period of rapid and significant aging that will require major fiscal adjustments. But the aging of these societies may be a cloud with a silver lining coming, in this case, in the form of capital deepening that will raise real wages. In a previous model that excluded China we predicted that tax hikes needed to pay benefits along the developed world’s demographic transition would lead to a major capital shortage, reducing real wages per unit of human capital over time by one fifth. A recalibration of our original model that treats government purchases of capital goods as investment rather than current consumption suggests this concern was overstated. With government investment included, we find much less crowding out over the course of the century and only a 4 percent long-run decline in real wages. Adding China to the model further alters, indeed, dramatically alters, the model’s predictions. Even though China is aging rapidly, its saving behavior, growth rate, and fiscal policies are currently very different from those of developed countries. If successive cohorts of Chinese continue to save like current cohorts, if the Chinese government can restrain growth in expenditures, and if Chinese technology and education levels ultimately catch up with those of the West and Japan, the model’s long run looks much brighter. China eventually becomes the world’s saver and, thereby, the developed world’s savoir with respect to its long-run supply of capital and long-run general equilibrium prospects. And, rather than seeing the real wage per unit of human capital fall, the West and Japan see it rise by one fifth percent by 2030 and by three fifths by 2100. These wage increases are over and above those associated with technical progress, which we model as increasing the human capital endowments of successive cohorts. Even if the Chinese saving behavior (captured by its time preference rate) gradually approaches that of Americans, developed world real wages per unit of human capital are roughly 17 percent higher in 2030 and 4 percent higher at the end of the century. Without China they’d be only 2 percent higher in 2030 and, as mentioned, 4 percent lower at Century’s end. What’s more, the major short-run outflow of the developed world’s capital to China predicted by our model does not come at the cost of lower wages in the developed world. The reason is that the knowledge that their future wages will be higher (thanks to China’s future capital accumulation) leads our model’s workers to cut back on their current labor supply. So the shortrun outflow of capital to China is met with a commensurate short-run reduction in developed world labor supply, leaving the short-run ratio of physical capital to human capital, on which wages positively depend, actually somewhat higher than would otherwise be the case. Our model does not capture the endogenous determination of skill premiums studied by Heckman and Taber (1996). Doing so could well show that trade with China, at least in the short run, explains much of the relative decline in the wages of low-skilled workers in the developed world. Hence, we don’t mean to suggest here that all US, EU, and Japanese workers are being helped by trade with China, but rather that trade with China is, on average, raising the wages of developed world workers and will continue to do so. The notion that China, India, and other developing countries will alleviate the developed world’s demographic problems has been stressed by Siegel (2005). Our paper, although it includes only one developing country – China – supports Siegel’s optimistic long-term macroeconomic view. On the other hand, our findings about the developed world’s fiscal condition are quite troubling. Even under the most favorable macroeconomic scenario, tax rates will rise dramatically over time in the developed world to pay baby boomers their government-promised pension and health benefits. As Argentina has so recently shown, countries can grow quite well for years even with unsustainable fiscal policies. But if they wait too long to address those policies, the financial markets will do it for them, with often quite ruinous consequences.

    Dynamic Globalization and its Potentially Alarming Prospects for Low-Wage Workers

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    Will incomes of low and high skilled workers continue to diverge? Yes says our paper's dynamic, six-good, five-region - U.S., Europe, N.E. Asia (Japan, Korea, Taiwan, Hong Kong), China, and India -, general equilibrium, life-cycle model. The model predicts a near doubling of the ratio of high- to low-skilled wages over the century. Increasing wage inequality arises from a traditional source - a rising worldwide relative supply of unskilled labor, reflecting Chinese and Indian productivity improvements. But China's and India's education policies matter. If successive Chinese and Indian cohorts become more skilled, major exacerbation of inequality will be precluded.Demographic transition, overlapping generations (OLG), computable general equilibrium models (CGE)
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