Is there Really a Unit Root in the Inflation Rate? More Evidence from Panel Data Models

Time series unit root evidence suggests that inflation is nonstationary. By contrast, when using more powerful panel unit root tests, Culver and Papell (1997) find that inflation is stationary. In this paper, we test the robustness of this result by applying a battery of recent panel unit root tests. The results suggest that the stationarity of inflation holds even after controlling for crosssectional dependence and structural change.Unit Root; Inflation; Cross-Sectional Dependence; Structural Change

Mixed Signals Among Tests for Panel Cointegration

In this paper, we study the effect that different serial correlation adjustment methods can have on panel cointegration testing. As an example, we consider the very popular tests developed by Pedroni (1999, 2004). Results based on both simulated and real data suggest that different adjustment methods can lead to significant variations in test outcome, and thus also in the conclusions.Panel Data; Cointegration Testing; Parametric and Semiparametric Methods

Panel Cointegration and the Monetary Exchange Rate Model

This paper re-examines the validity of the monetary exchange rate model during the post-Bretton Woods era for 18 OECD countries. Our analysis simultaneously considers the presence of both cross-sectional dependence and multiple structural breaks, which have not received much attention in previous studies of the monetary model. The empirical results indicate that the monetary model emerges only when the presence of structural breaks and cross-country dependence has been taken into account. Evidence is also provided suggesting that the breaks in the monetary model can be derived from the underlying purchasing power parity relation.

Can Panel Data Really Improve the Predictability of the Monetary Exchange Rate Model?

A common explanation for the inability of the monetary model to beat the random walk in forecasting future exchange rates is that conventional time series tests may have low power, and that panel data should generate more powerful tests. This paper provides an extensive evaluation of this power argument to the use of panel data in the forecasting context. In particular, by using simulations it is shown that although pooling of the individual prediction tests can lead to substantial power gains, pooling only the parameters of the forecasting equation, as has been suggested in the previous literature, does not seem to generate more powerful tests. The simulation results are illustrated through an empirical application.Monetary Exchange Rate Model; Forecasting; Panel Data; Pooling; Bootstrap

Testing for Convergence in Carbon Dioxide Emissions Using a Century of Panel Data

This paper tests the convergence in per-capita carbon dioxide emissions for a collection of developed and developing countries using data spanning the period 1870 to 2002. For this purpose, three recently developed panel unit root tests that permit for dependence among the individual countries are employed. The results lend strong support in favor of convergence for the panel as a whole. Estimates of the speed of this convergence is also provided.Emissions convergence; Panel unit root tests; Common factors; Half-life

Laser beamed power: Satellite demonstration applications

It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries

Twice Chosen: Spouse Matching and Earnings Among Women in First and Second Marriages

This study examines spousal matching for females in second-order marriages. It is based on detailed data from longitudinal Swedish population data registers. We aim to follow women who marry, divorce, and subsequently remarry compared with females who marry and stay married over the course of the study interval. The earnings of both groups are modeled through regression analysis in the year prior to their marriages along with the earnings of each husband. The residuals from the regressions represent unobservables in the process of earnings generation. From the regressions we obtain spouse-to-be pairs of earnings residuals and we measure the correlation of residuals for each marital regime. Overall, we find significant positive correlations for all three of the marital partitions. The correlation tends to be smaller for the first of a sequence of marriages for women who divorce than for women who marry and stay so. For the second of the successive marriages, however, the correlation of the residuals is larger than that for women who marry but once. We also find evidence of “matching” between successive husbands. Women who marry men with unmeasured positive earnings capacities, in the event of divorce, tend to select and match in a similar fashion the second time around.Marital matching; Remarriage; Assortative mating; Earnings

A Rich Population of X-ray Emitting Wolf-Rayet Stars in the Galactic Starburst Cluster Westerlund 1

Recent optical and IR studies have revealed that the heavily-reddened starburst cluster Westerlund 1 (Wd 1) contains at least 22 Wolf-Rayet (WR) stars, comprising the richest WR population of any galactic cluster. We present results of a senstive Chandra X-ray observation of Wd 1 which detected 12 of the 22 known WR stars and the mysterious emission line star W9. The fraction of detected WN stars is nearly identical to that of WC stars. The WN stars WR-A and WR-B as well as W9 are exceptionally luminous in X-rays and have similar hard heavily-absorbed spectra with strong Si XIII and S XV emission lines. The luminous high-temperature X-ray emission of these three stars is characteristic of colliding wind binary systems but their binary status remains to be determined. Spectral fits of the X-ray bright sources WR-A and W9 with isothermal plane-parallel shock models require high absorption column densities log N$_{H}$ = 22.56 (cm$^{-2}$) and yield characteristic shock temperatures kT_shock ~ 3 keV (T ~ 35 MK).Comment: ApJL, 2006, in press (3 figures, 1 table

Improving Pasture Productivity and Persistence by Renovating or Rejuvenating

Forages make up a large part of the feed requirements of beef cattle, and grazing remains the most economical form of feed delivery. However, several years after pasture establishment, forage productivity and longevity usually decline. Maintaining productive forage stands in the long term becomes a major challenge that beef producers face. A 3-yr on-farm study was conducted to determine the comparative effects of several pasture rejuvenation methods, such as spraying of herbicides to control weeds and brush, Spray herbicide + direct seed in spring (RSS), forage seeding methods, fertilizer application (FERT), and pasture rest as well as aeration/spiking in fall (AF) and aeration/spiking in spring (AS) on forage dry matter (DM) yield and forage quality. Breaking & reseeding (B&R), which is a grassland renovation method, was compared to these four pasture rejuvenation methods. A no treatment method (control) was included for comparison. Three years after treatments were implemented, pasture rejuvenation methods did significantly affect (P\u3c 0.05) grass botanical composition but did not significantly influence (P\u3e 0.05) total DM yield and legume botanical composition. The only method that involved land cultivation and reseeding (B&R) showed higher total input costs than other methods. Overall, RSS as well as AS, AF and FERT had greater 2-year total forage production, revenue and returns, and profit over control than the other treatment methods

Hairpins in the conformations of a confined polymer

If a semiflexible polymer confined to a narrow channel bends around by 180 degrees, the polymer is said to exhibit a hairpin. The equilibrium extension statistics of the confined polymer are well understood when hairpins are vanishingly rare or when they are plentiful. Here we analyze the extension statistics in the intermediate situation via experiments with DNA coated by the protein RecA, which enhances the stiffness of the DNA molecule by approximately one order of magnitude. We find that the extension distribution is highly non-Gaussian, in good agreement with Monte Carlo simulations of confined discrete wormlike chains. We develop a simple model that qualitatively explains the form of the extension distribution. The model shows that the tail of the distribution at short extensions is determined by conformations with one hairpin.Comment: Revised version. 22 pages, 7 figures, 2 tables, supplementary materia