Gravity in a Box

We consider a brane-world construction which incorporates a finite region of flat space, ``the box,'' surrounded by a region of anti-de Sitter space. This hybrid construction provides a framework which interpolates between the scenario proposed by Arkani-Hamed, Dimopoulos and Dvali, and that proposed by Randall and Sundrum. Within this composite framework, we investigate the effects of resonant modes on four-dimensional gravity. We also show that, on a probe brane in the anti-de Sitter region, there is enhanced production of on-shell nonresonant modes. We compare our model to some recent attempts to incorporate the Randall-Sundrum scenario into superstring theory.Comment: 15 pages, 1 figur

Direct Measure of Giant Magnetocaloric Entropy Contributions in Ni-Mn-In

Off-stoichiometric alloys based on Ni 2 MnIn have drawn attention due to the coupled first order magnetic and structural transformations, and the large magnetocaloric entropy associated with the transformations. Here we describe calorimetric and magnetic studies of four compositions. The results provide a direct measure of entropy changes contributions including at the first-order phase transitions, and thereby a determination of the maximum field-induced entropy change corresponding to the giant magnetocaloric effect. We find a large excess entropy change, attributed to magneto-elastic coupling, but only in compositions with no ferromagnetic order in the high-temperature austenite phase. Furthermore, a molecular field model corresponding to antiferromagnetism of the low-temperature phases is in good agreement, and nearly independent of composition, despite significant differences in overall magnetic response of these materials

Real Estate Collateral Value and Investment: The Case of China

Previous research on the United States and Japan finds economically large impacts of changing real estate collateral value on firm investment that amplified the business cycles of those countries. Working with unique data on land values in 35 major Chinese markets and a panel of firms outside the real estate industry, we estimate investment equations that yield no evidence of a collateral channel effect. Further analysis indicates that China’s debt is not characterized by the frictions that give rise to collateral channel effects elsewhere. Essentially, financially constrained borrowers appear able credibly to commit to repay debt in China. While there is no impact on investment via the collateral channel, our results should not be interpreted as implying there will be no negative fallout from a potential real estate bust on the Chinese economy. There likely would be, but through different channels

Evaluating Conditions in Major Chinese Housing Markets

High and rising prices in Chinese housing markets have attracted global attention. Price-to-rent ratios in Beijing and seven other large markets across the country have increased by 30% to 70% since the beginning of 2007. Current price-to-rent ratios imply very low user costs of no more than 2%–3% of house value. Very high expected capital gains appear necessary to justify such low user costs of owning. Our calculations suggest that even modest declines in expected appreciation would lead to large price declines of over 40% in markets such as Beijing, absent offsetting rent increases or other countervailing factors. Price-to-income ratios also are at their highest levels ever in Beijing and select other markets, but urban income growth has outpaced price appreciation in major markets off the coast. Much of the increase in prices is occurring in land values. Using data from the local land auction market in Beijing, we are able to produce a constant quality land price index for that city. Real, constant quality land values have increased by nearly 800% since the first quarter of 2003, with half that rise occurring over the past two years. State-owned enterprises controlled by the central government have played an important role in this increase, as our analysis shows they paid 27% more than other bidders for an otherwise equivalent land parcel