Gravitational Constraint Combinations Generate a Lie Algebra

We find a first--order partial differential equation whose solutions are all ultralocal scalar combinations of gravitational constraints with Abelian Poisson brackets between themselves. This is a generalisation of the Kucha\v{r} idea of finding alternative constraints for canonical gravity. The new scalars may be used in place of the hamiltonian constraint of general relativity and, together with the usual momentum constraints, replace the Dirac algebra for pure gravity with a true Lie algebra: the semidirect product of the Abelian algebra of the new constraint combinations with the algebra of spatial diffeomorphisms.Comment: 10 pages, latex, submitted to Classical and Quantum Gravity. Section 3 is expanded and an additional solution provided, minor errors correcte

Nonlinear bending-torsional vibration and stability of rotating, pretwisted, preconed blades including Coriolis effects

The coupled bending-bending-torsional equations of dynamic motion of rotating, linearly pretwisted blades are derived including large precone, second degree geometric nonlinearities and Coriolis effects. The equations are solved by the Galerkin method and a linear perturbation technique. Accuracy of the present method is verified by comparisons of predicted frequencies and steady state deflections with those from MSC/NASTRAN and from experiments. Parametric results are generated to establish where inclusion of only the second degree geometric nonlinearities is adequate. The nonlinear terms causing torsional divergence in thin blades are identified. The effects of Coriolis terms and several other structurally nonlinear terms are studied, and their relative importance is examined

Quantum atom optics with fermions from molecular dissociation

We study a fermionic atom optics counterpart of parametric down-conversion with photons. This can be realized through dissociation of a Bose-Einstein condensate of molecular dimers consisting of fermionic atoms. We present a theoretical model describing the quantum dynamics of dissociation and find analytic solutions for mode occupancies and atomic pair correlations, valid in the short time limit. The solutions are used to identify upper bounds for the correlation functions, which are applicable to any fermionic system and correspond to ideal particle number-difference squeezingComment: Changes in response to referees' comments, updated reference

Multilateral, Regional, and Bilateral Trade-Policy Options for the United States and Japan

We have used the Michigan Model of World Production and Trade to simulate the economic effects on the United States, Japan, and other major trading countries/regions of a prospective new round of WTO multilateral trade negotiations and a variety of regional/bilateral free trade agreements (FTAs) involving the United States and Japan. We estimate that an assumed reduction of post-Uruguay Round tariffs on agricultural and industrial products and services barriers by 33 percent in a new WTO trade round would increase world welfare by $613.0 billion, with gains of$177.3 billion for the United States, $123.7 billion for Japan, and significant gains for all other industrialized and developing countries/regions. If there were global free trade with all post-Uruguay Round trade barriers completely removed, world welfare would increase by$1.9 trillion, with gains of $537.2 billion (5.9 percent of GNP) for the United States and$374.8 billion (5.8 percent of GNP) for Japan. Regional agreements such as an APEC FTA, an ASEAN Plus 3 FTA, and a Western Hemisphere FTA would increase global and member country welfare but much less so than a new WTO multilateral trade round would. Separate bilateral FTAs involving Japan with Singapore, Mexico, Chile, and Korea and the United States with Chile, Singapore, and Korea would have positive, though generally small, welfare effects on the partner countries, but potentially disruptive sectoral employment shifts in some countries. There would be trade diversion and detrimental welfare effects on some nonmember countries for both the regional and bilateral FTAs analyzed. The welfare gains from multilateral trade liberalization are therefore considerably greater than the gains from preferential trading arrangements and more uniformly positive for all countries.

Computational Analysis of the Impact on India of the Uruguay Round and the Forthcoming WTO Trade Negotiations

The Indian economy has experienced a major transformation during the decade of the 1990s. Apart from the impact of various unilateral economic reforms undertaken since 1991, the economy also had to reorient itself to the changing multilateral trade discipline within the newly written GATT-WTO framework. The unilateral trade policy measures have encompassed exchange-rate policy, foreign investment, external borrowing, import licensing, custom tariffs, and export subsidies. The multilateral aspect of India's trade policy refers to India's WTO commitments regarding trade in goods and services, trade-related investment measures, and intellectual property rights. The present study analyzes the economic effects on India and other major trading countries/regions of the Uruguay Round (UR) trade liberalization and the liberalization that might be undertaken in a new WTO negotiating round. India's welfare gain is expected ot be 1.1% ($4.7 billion over its 2005 GDP) when the UR scenarios get fully implemented. The additional welfare gain is an estimated 2.7$11.4 billion) when the assumed future WTO round of multilateral trade liberalization is achieved. Resources would be allocated in India to the labor-intensive sectors such as textiles, clothing, leather and leather products, and food, beverages, and tobacco. These sectors would also experience growth in output and exports. Real returns to both labor and capital would increase in the economy. The scale effect (percent change in output per firm) is positive for all the ten sectors of manufacturing, indicating that Indian firms become more efficient than before. Finally, even if India undertakes unilateral trade liberalization of the order indicated in the WTO multilateral scenarios, it would still benefit, although less so than with multilateral liberalization.http://deepblue.lib.umich.edu/bitstream/2027.42/39696/3/wp312.pd

Developing Countries' Stake in the Doha Round

In this paper we discuss the various aspects of the Doha Round of Multilateral Trade Negotiations in the WTO that offer potential benefits for developing countries. We then use the Michigan Model of World Production and Trade to simulate the economic effects on the major trading countries/regions of the reductions in tariffs, subsidies in agriculture, and barriers in services that may be negotiated in the Doha Round, as well as a variety of regional free trade agreements (FTAs). We estimate that an assumed reduction of post-Uruguay Round tariffs and other barriers on agricultural and industrial products and services by 33 percent in the Doha Round would increase world welfare by $686.4 billion, with significant gains for all industrialized and developing countries/regions. Regional agreements such as an APEC FTA, an ASEAN Plus 3 FTA, and a Western Hemisphere FTA would increase global and member country welfare, but by much less than the Doha multilateral trade round. There would also be trade diversion and detrimental welfare effects on some nonmember countries for the FTAs analyzed. The welfare gains from multilateral trade liberalization are therefore considerably greater than the gains from preferential trading arrangements and more uniformly positive for all countries.WTO, Trade Liberalization

CGE Modeling and Analysis of Multilateral and Regional Negotiating Options

We have used the Michigan Model of World Production and Trade to simulate the economic effects on the United States, Japan, and other major trading countries/regions of: the Uruguay Round of multilateral trade negotiations completed in 1993-94; a prospective new round of WTO multilateral trade negotiations; and a variety of regional/bilateral free trade agreements (FTAs) involving the United States and Japan. We estimate that the Uruguay Round negotiations increased global economic welfare by $75.1 billion annually, with gains of$12.9 billion for the United States and $15.6 billion for Japan. An assumed reduction of all post-Uruguay Round tariffs on agricultural and industrial products and of all services barriers by 33 percent in a new WTO trade round is estimated to increase world welfare by$613.0 billion, with gains of $177.3 billion for the United States and$123.7 billion for Japan. If there were global free trade with all post-Uruguay Round trade barriers completely removed, then world welfare would increase by $1.9 trillion, with gains of$537.2 billion (5.9 percent of GNP) for the United States and $374.8 billion (5.8 percent of GNP) for Japan. Elimination of APEC-member country bilateral post-Uruguay Round tariffs on agricultural and industrial products and services barriers is estimated to increase world welfare by$764.4 billion, with gains of $294.7 billion for the United States and$283.1 billion for Japan and losses of $7.0 billion for the European Union/EFTA and$1.0 billion for South Asia. Separate bilateral FTAs involving Japan with Singapore, Mexico, South Korea, and Chile and an ASEAN Plus-3 FTA involving Japan, China/Hong Kong, and South Korea would have positive, though generally small, welfare effects, but potentially disruptive sectoral employment shifts in some member countries. Depending on the agreement, there may be detrimental welfare effects on some nonmembers. The welfare gains from multilateral trade liberalization are therefore considerably greater than the gains from preferential trading arrangements and more uniformly positive for all countries.