Extrapolation Theory and the Pricing of REIT Stocks

This paper is the winner of the best paper on Real Estate Investment Trusts award (sponsored by the National Association of Real Estate Investment Trusts (NAREIT)] presented at the 2005 American Real Estate Society Annual Meeting. This study evaluates the investment prospects of value stocks in the real estate investment trust (REIT) market. Value stocks are defined as those that carry low prices relative to their earnings, dividends, book assets, or other measures of fundamental value. The empirical results show that from 1990 onwards, value REITs provide superior returns without exposing investors to higher risks. The evidence is consistent with the extrapolation theory, which attributes the mispricing to investors over extrapolating past corporate results into the future. Interestingly, the findings reveal that such extrapolation is asymmetric in the REIT market. While value REITs are underpriced in accordance with the extrapolation theory, no evidence is found that growth REITs are overpriced. The value anomaly also exhibited several temporal traits. Firstly, the value premium varies over time. Secondly, the magnitude of the premium is inversely associated with the market performance. Finally, the value anomaly is not evident in the pricing of REITs in the 1980s.

An eigenmode analysis of time delays in an acoustically coupled multi-bubble system

The acoustic properties of an inhomogeneous bubbly medium are complex owing to the absorption and re-emission of acoustic energy by the bubbles. This phenomena can be approximated by a globally coupled system of linear oscillators. In previous studies, it has been shown that this simple model can produce results that are in qualitative agreement with experimental data. In order to achieve better quantitative agreement with experimental data, time-delays need to be introduced into the mathematical model. In the present study, the resulting delayed differential equations were solved numerically using a 4th order Runge-Kutta method. The numerical methodology was validated by comparing simplified cases with the solution using analytical methods. The effects of time-delay were assessed by comparing non-timedelayed and time-delayed versions of the mathematical model. Results from numerical simulations were then compared to assess the effects and importance of the inclusion of time-delay in the mathematical model. This study shows that the inclusion of time-delay has a noticeable effect on the lower frequency modes of the model. This effect propagates to the higher frequency modes as the magnitude of the time-delay increases. The results also shows that the time-delay shifts the dominant modes from the lower frequency modes to the higher frequency mode

Complex Relationships between Competing Guilds along Large-Scale Environmental Gradients

Despite much research over the past 30 years there is still little general understanding of how the outcomes of interactions vary along environmental gradients, particularly at large geographic scales. A simple expectation is that decreasing environmental quality should reduce densities of competitors and hence the effects of competition should weaken in poorer environments. A counter-intuitive consequence is that associations between densities of competitors might change from negative to positive as environments decrease in quality. Here we test these predictions in a set of vascular plant communities where perennial species share space and resources with less competitive annuals. We surveyed nine grey dune communities annually for 5 years along a cross-European latitudinal gradient of habitat quality. We find that densities of annual and perennial species are negatively correlated at the high-quality end of the gradient, while at the low-quality end guild densities are uncorrelated or positively correlated, consistent with a weakening of competition linked to increasing environmental limitations. Our results suggest that even simple interactions can give rise to non-obvious changes in species associations along environmental gradients. They highlight that understanding the outcome of species interactions may require explicit characterization of their changing intensity with environmental quality, and that the factors limiting species’ co-distribution can vary along environmental gradients

A New Phenomenology for the Disordered Mixed Phase

A universal phase diagram for type-II superconductors with weak point pinning disorder is proposed. In this phase diagram, two thermodynamic phase transitions generically separate a ``Bragg glass'' from the disordered liquid. Translational correlations in the intervening ``multi-domain glass'' phase are argued to exhibit a significant degree of short-range order. This phase diagram differs significantly from the currently accepted one but provides a more accurate description of experimental data on high and low-T$_c$ materials, simulations and current theoretical understanding.Comment: 15 pages including 2 postscript figures, minor changes in published versio

Global three-dimensional flow of a neutron superfluid in a spherical shell in a neutron star

We integrate for the first time the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations of motion of a $^{1}S_{0}$-paired neutron superfluid in a rotating spherical shell, using a pseudospectral collocation algorithm coupled with a time-split fractional scheme. Numerical instabilities are smoothed by spectral filtering. Three numerical experiments are conducted, with the following results. (i) When the inner and outer spheres are put into steady differential rotation, the viscous torque exerted on the spheres oscillates quasiperiodically and persistently (after an initial transient). The fractional oscillation amplitude ($\sim 10^{-2}$) increases with the angular shear and decreases with the gap width. (ii) When the outer sphere is accelerated impulsively after an interval of steady differential rotation, the torque increases suddenly, relaxes exponentially, then oscillates persistently as in (i). The relaxation time-scale is determined principally by the angular velocity jump, whereas the oscillation amplitude is determined principally by the gap width. (iii) When the mutual friction force changes suddenly from Hall-Vinen to Gorter-Mellink form, as happens when a rectilinear array of quantized Feynman-Onsager vortices is destabilized by a counterflow to form a reconnecting vortex tangle, the relaxation time-scale is reduced by a factor of $\sim 3$ compared to (ii), and the system reaches a stationary state where the torque oscillates with fractional amplitude $\sim 10^{-3}$ about a constant mean value. Preliminary scalings are computed for observable quantities like angular velocity and acceleration as functions of Reynolds number, angular shear, and gap width. The results are applied to the timing irregularities (e.g., glitches and timing noise) observed in radio pulsars.Comment: 6 figures, 23 pages. Accepted for publication in Astrophysical Journa

Symmetric mode resonance of bubbles near a rigid boundary - the nonlinear case with time delay effects

A fundamental understanding of the effect of a surface on the resonance frequency of bubbles will be useful in the future development of diagnostic medical ultrasound equipment, and specifically in the area of targeted contrast agents for the screening and possible treatment of colon cancer. In this work we turn to the wall effects on the nonlinear resonance frequency response of air bubbles in water, following on from an earlier work which considered linear interactions (E. M. B. Payne, S. Illesinghe, A. Ooi, R. Manasseh, J. Acoust Soc. Am. 118, 2841-2849 (2005)). Numerical results for micron-sized bubbles near a rigid boundary are presented, showing the shift in frequency caused by the presence of the boundary and the presence of other bubbles. Time delay effects are also included, showing a damping of the frequency response. Simulations are limited to the special case where all bubbles are in phase (i.e., the symmetric mode), which refers to the case where all bubbles have the same initial conditions and are subjected to the same excitation pressure field. As a result they have identical time histories. An experimental method for measuring the frequency response of a single bubble attached to a surface is also briefly mentioned

Evidence for Surface Andreev Bound states in Cuprate Superconductors from Penetration Depth Measurements

Tunneling and theoretical studies have suggested that Andreev bound states form at certain surfaces of unconventional superconductors. Through studies of the temperature and field dependence of the in-plane magnetic penetration depth lambda_ab at low temperature, we have found strong evidence for the presence of these states in clean single crystal YBCO and BSCCO. Crystals cut to expose a [110] interface show a strong upturn in lambda_ab at around 7K, when the field is oriented so that the supercurrents flow around this surface. In YBCO this upturn is completely suppressed by a field of ~0.1 T.Comment: 4 pages 2 column revtex + 4 postscript figures. Submitted to PR

Characterization of a Plain Broadband Textile PIFA

Bandwidth characteristic of a wearable antenna is one of the major factors in determining its usability on the human body. In this work, a planar inverted-F antenna (PIFA) structure is proposed to achieve a large bandwidth to avoid serious antenna reflection coefficient detuning when placed in proximity of the body. The proposed structure is designed based on a simple structure, in order to provide practicality in application and maintain fabrication simplicity. Two different types of conductive textiles, namely Pure Copper Polyester Taffeta Fabric (PCPTF) and ShieldIt, are used in order to proof its concept, in comparison with a metallic antenna made from copper foil. The design is spaced and fabricated using a 6 mm thick fleece fabric. To cater for potential fabrication and material measurement inaccuracies, both antennas' performance are also investigated and analyzed with varying physical and material parameters. From this investigation, it is found that the proposed structure's extended bandwidth enabled the antenna to function with satisfactory on-body reflection coefficients, despite unavoidable gain and efficiency reduction

c-axis penetration depth in Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} single crystals measured by ac-susceptibility and cavity perturbation technique

The $c$-axis penetration depth $\Delta\lambda_c$ in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (BSCCO) single crystals as a function of temperature has been determined using two techniques, namely, measurements of the ac-susceptibility at a frequency of 100 kHz and the surface impedance at 9.4 GHz. Both techniques yield an almost linear function $\Delta\lambda_c(T)\propto T$ in the temperature range T<0.5 T_c. Electrodynamic analysis of the impedance anisotropy has allowed us to estimate $\lambda_c(0)\approx 50 \mu$m in BSCCO crystals overdoped with oxygen ($T_c\approx 84$ K) and $\lambda_c(0)\approx 150 \mu$m at the optimal doping level ($T_c\approx 90$ K).Comment: 5 pages, 4 figure

Sub-maximal exercise testing in silicosis and correlation with lung function

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