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

Deriving field theories for particles of arbitrary spin with and without supersymmetry

We review the derivation of light-cone interaction vertices for fermionic and bosonic fields of arbitrary spin. The resulting amplitudes and their factorization properties are discussed. We then show how this symmetry-based approach works for theories with extended supersymmetry like N=4 Yang-Mills theory and N=8 supergravity.Comment: 18 pages. Contribution to the proceedings of the "International Workshop on Higher Spin Gauge Theories", NTU, Singapore (4-6 November, 2015

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

Hepatic Failure: Role for biochemists and nutrition experts

Nutritional support to hepatic failure patients is challenging and requires experience, skill, careful planning and meticulous follow-up. It is indeed an attempt to replenish the lost power of one of the most vital organs we possess

Gene Therapy – Potential, Pros, Cons and Ethics

Genetic technology poses risks along with its rewards, just as any technology has in the past. To stop its development and forfeit the benefits gene therapy could offer would be a far greater mistake than forging ahead could ever be. People must always try to be responsible with their new technology, but gene therapy has the potential to be the future of medicine and its possibilities must be explored

The N=8 Supergravity Hamiltonian as a Quadratic Form

We conjecture that the light-cone Hamiltonian of N=8 Supergravity can be expressed as a quadratic form. We explain why this rewriting is unique to maximally supersymmetric theories. The N=8 quartic interaction vertex is constructed and used to verify that this conjecture holds to second order in the coupling constant.Comment: 23 pages, minor corrections in appendix