Theories with Memory

Dimensionally reduced supersymmetric theories retain a great deal of information regarding their higher dimensional origins. In superspace, this "memory" allows us to restore the action governing a reduced theory to that describing its higher-dimensional progenitor. We illustrate this by restoring four-dimensional N=4 Yang-Mills to its six-dimensional parent, N=(1,1) Yang-Mills. Supersymmetric truncation is introduced into this framework and used to obtain the N=1 action in six dimensions. We work in light-cone superspace, dealing exclusively with physical degrees of freedom.Comment: 18 pages, reference adde

Ties that bind: bilateral trade's role in synchronizing business cycles

For most of the past year, economies in all parts of the world have been weakening--from outright recessions in the U.S. and parts of Europe to sharply slower growth in China, India and other emerging economies. The pattern provides the latest example of international business-cycle synchronization--the tendency for countries to experience macroeconomic fluctuations of similar timing and magnitude. ; While today's synchronization isn't unusual, it raises questions about the forces that transmit economic fluctuations from one country to another. An important factor to consider is international trade. Over long periods of time, countries with deeper trade ties are more closely synchronized. This occurs even though trade with any particular partner makes up a fairly small part of economic activity in most countries.International trade ; Business cycles

Sovereign debt: a matter of willingness, not ability, to pay

Greece, which shook international markets with the disclosure of its deep indebtedness, has struggled recently to borrow money. Among European governments, Ireland, Italy, Portugal and Spain have also had difficulty selling bonds. Even though these governments probably have assets that exceed their debts, investors worry about the risk of default. This belief stems in part from the nature of sovereign debt. Governments aren't subject to formal bankruptcy regulations, leaving investors few legal rights over borrower assets, even if they could be liquidated. Consequently, the likelihood of default is not strictly determined by measures of solvency or asset liquidity. Rather, it's a matter of the political willingness to repay creditors. A perceived high likelihood of default increases interest rates on the new debt necessary to finance deficits and payments on outstanding obligations. ; What is an effective response to such debt crises? European policymakers have announced various aid measures--for example, loans at below-market interest rates--for Greece and other troubled governments. With high debts and deficits, these governments must continue borrowing to fund expenses and make debt payments; wide interest rate spreads make that difficult. Policies such as subsidized loans make governments feel richer and thus more willing to pay debt service than face the costs of default. More generally, policy measures aimed at preventing sovereign default ultimately need to raise incentives to repay debt, either by making the payment of debt less costly or by raising default costs.Debts, Public ; Budget deficits ; Interest rates ; Default (Finance) ; Greece

Distance and the impact of ‘gravity’ help explain patterns of international trade

United States trade with other countries declined dramatically during the recent recession, with the volumes of imports and exports each falling about 21 percent from third quarter 2008 to second quarter 2009. By comparison, real gross domestic product (GDP) contracted only 4 percent (Chart 1). A subsequent rebound in international trade flows is just as striking and has been one of the most robust indicators during the accelerating recovery.International trade ; Business cycles

Laboratory Generated Artifacts in Plasma Amino acid Quantitation

The pace of physicians’ involvement in amino acid metabolism has been enormous in the last five decades. With further development of technology to identify and quantitate upto picomoles of amino acids, their metabolites and related peptides, diagnosis and effective medical intervention in cases of inherited metabolic disorders have been well within the reach of the clinician. Automatic amino acid analyzers have become an essential part of major medical and research centers around the world. The technology has come indeed as a boon to physicians who in particular deal with inherited defects of amino acid metabolism. However, the technology comes with the risk of major deviations from the actual results when a few minor variations are not looked into. Trivial variations in basic steps of obtaining the sample, the choice of anticoagulant, hemolysis etc. can cause significant variations in the resulting values, particularly while dealing with inherited defects of amino acid metabolism and their treatment/management. Effects of such factors are revisited here for the benefit of the modern day laboratory personnel