Money and the Open Economy Business Cycle: A Flexible Price Model

This paper develops an open-economy model of the business cycle. The nominal prices in the model are flexible and monetary nonneutrality is developed using information confusion about the sources of disturbances to demand coupled with differential persistence of demand shocks. Firms use inventories to smooth their production, and consumers follow a stochastic permanent income expenditure function. The major implication of the model is that unperceived monetary disturbances improve the terms of trade and increase real output in contrast to sticky price models in which the terms of trade deteriorates. This implication of the model is examined empirically.

Asset Price Volatility, Bubbles, and Process Switching

Evidence of excess volatilities of asset prices compared with those of market fundamentals is often attributed to speculative bubbles. This study examines the sense in which speculative bubbles could in theory lead to excess volatility, hut it demonstrates that some of the variance hounds evidence reported to date precludes bubbles as a reason why asset prices might violate such hounds. The findings must represent some other model misspecffication or market inefficiency. One important misspecification occurs when there searcher incorrectly specifies the time series properties of market fundamentals. A bubble-free example economy characterized by a potential switch in government policies produces paths of asset prices that would appear, to an unwary researcher, to contain bubbles.

Changes in fish populations in the Lower Canyons of the Rio Grande

The Lower Canyons of the Rio Grande suffer from environmental degradation that has negatively impacted native fish populations and their distributions. Macrhybopsis aestivalis (speckled chub), Notropis jemezanus (Rio Grande shiner), Rhinichthys cataractae (longnose dace) and Cycleptus elongatus (blue sucker) populations appear to have suffered recent declines. Although diminished water quantity is likely an important factor in these declines, related changes in channel morphology precipitated by massive stands of Arundo donax (giant reed) and Tamarix sp. (salt cedar) may also be responsible. These invasive exotics have essentially channelized the river, disrupted normal sediment distribution and reduced shallow, low-velocity habitats. Much of the Lower Canyons of the Rio Grande are devoid of sandy sediment and most riffles are now composed of gravel and cobble.Integrative Biolog

Recombination coefficients for O II lines in nebular conditions

We present the results of a calculation of recombination coefficients for O^{2+} + e^- using an intermediate coupling treatment that fully accounts for the dependence of the distribution of population among the ground levels of O^{2+} on electron density and temperature. The calculation is extended down to low electron temperatures where dielectronic recombination arising from Rydberg states converging on the O^{2+} ground levels is an important process. The data, which consist of emission coefficients for 8889 recombination lines and recombination coefficients for the ground and metastable states of O^+ are in Cases A, B and C, and are organised as a function of the electron temperature and number density, as well as wavelength. An interactive fortran 77 data server is also provided as an accessory for mining the line emission coefficients and obtaining Lagrange interpolated values for any choice of the two variables between the explicitly provided values for any set of wavelengths. Some illustrations of the application of the new data to nebular observations are also provided.Comment: 15 pages, 7 figures, 6 table

Solvent fluctuations around solvophobic, solvophilic and patchy nanostructures and the accompanying solvent mediated interactions

Using classical density functional theory (DFT) we calculate the density profile $\rho({\mathbf r})$ and local compressibility $\chi({\mathbf r})$ of a simple liquid solvent in which a pair of blocks with (microscopic) rectangular cross-section are immersed. We consider blocks that are solvophobic, solvophilic and also ones that have both solvophobic and solvophilic patches. Large values of $\chi({\mathbf r})$ correspond to regions in space where the liquid density is fluctuating most strongly. We seek to elucidate how enhanced density fluctuations correlate with the solvent mediated force between the blocks, as the distance between the blocks and the chemical potential of the liquid reservoir vary. For sufficiently solvophobic blocks, at small block separations and small deviations from bulk gas-liquid coexistence, we observe a strongly attractive (near constant) force, stemming from capillary evaporation to form a low density gas-like intrusion between the blocks. The accompanying $\chi({\mathbf r})$ exhibits structure which reflects the incipient gas-liquid interfaces that develop. We argue that our model system provides a means to understanding the basic physics of solvent mediated interactions between nanostructures, and between objects such as proteins in water, that possess hydrophobic and hydrophilic patches.Comment: 19 pages, 21 figure

Uncountably many quasi-isometry classes of groups of type FPFP

Previously one of the authors constructed uncountable families of groups of type $FP$ and of $n$-dimensional Poincar\'e duality groups for each $n\geq 4$. We strengthen these results by showing that these groups comprise uncountably many quasi-isometry classes. We deduce that for each $n\geq 4$ there are uncountably many quasi-isometry classes of acyclic $n$-manifolds admitting free cocompact properly discontinuous discrete group actions.Comment: Version 2: minor corrections made, theorems now numbered by sectio

An Annotated Checklist of the Freshwater Fishes of Texas, with Keys to Identification of Species

Forty-five families and 247 species of fishes are known to inhabit the freshwaters of Texas. We report on the distribution and status of these fishes and provide a key to their identification. Of the native fishes originally found in Texas, five taxa, Notropis orca (phantom shiner), Notropis simus simus (Rio Grande bluntnose shiner), Cyprinella lutrensis blairi (Maravillas red shiner), Gambusia amistadensis (Amistad gambusia) and Gambusia georgei (San Marcos gambusia) are apparently extinct, and three, Oncorhynchus clarki virginalis (Rio Grande cutthroat trout), Hybognathus amarus (Rio Grande silvery minnow) and Gambusia senilis (blotched gambusia) appear to be extirpated from the state. More than 20 percent of the remaining primary freshwater species appear to be in some need of protection.Integrative Biolog