Saint Mary's University

About: Saint Mary's University is a education organization based out in Halifax, Nova Scotia, Canada. It is known for research contribution in the topics: Population & Stars. The organization has 1931 authors who have published 4993 publications receiving 143226 citations.

Measuring and Explaining Changes in REIT Liquidity: Moving Beyond the Bid/Ask Spread

Abstract: This paper investigates changes in REIT liquidity since the REIT boom of 1993. In contrast to previous research that investigates liquidity via the bid/ask spread, we examine the impact of trades on REIT share price movements. In the first part of the paper, we use trade by trade data for REITs traded on the major U.S. exchanges to estimate and compare Kyle's (1985) measure of inverse liquidity for the 1993 and 1996 time periods. For our full sample of equity REITs, there is a significant increase in REIT liquidity in terms of the median price impact of trades. The increasing importance of the "self-advised/self-managed" organizational structure is found to be a major factor driving increased REIT liquidity. Our results imply a decline in the asymmetric information faced by market makers and, therefore a reduction in the adverse selection costs of trading. The second part of the paper seeks to explain the factors driving the shift in the information environment in which REITs trade. Our investigation of the changes in the size distribution and resulting price impacts of REIT trades over the 1993-1996 period yields evidence of increased importance of informed traders to REIT price dynamics. By itself, the presence of more informed traders should decrease REIT liquidity. Our findings of increased liquidity, however, indicate that the increase in adverse selection costs due to the presence of more informed traders is more than offset by the increase in market thickness as a result of an increase in the number of uninformed (liquidity) traders.

Ophiolitic mélanges in crustal-scale fault zones: implications for the Late Palaeozoic tectonic evolution in West Junggar, China

Abstract: The Baijiantan and Darbut ophiolites in West Junggar are exposed in steep fault zones (>70°) containing serpentinite melange, in contact on either side with regionally distributed Upper Devonian-Lower Carboniferous ocean floor peperitic basalts and overlying sedimentary successions. The ophiolitic melanges show classic structural features created by strike-slip faulting and consistent shear sense indicators of left-slip kinematics. Sandstone blocks within the melanges resemble the surrounding sediments in lithology and age, indicating that the ophiolitic melanges consist of locally derived rocks. The ophiolitic melanges therefore originated from left-slip fault zones within a remnant basin and are not plate boundaries nor subduction suture zones. Sandstone is the youngest lithology involved in the melange and provides a maximum age for the melange of 322 Ma, whereas stitching plutons are younger than 302 Ma. Multiple clusters in zircon ages from single gabbro blocks in the melange at ~375, ~360, ~354, and ~340 Ma are inconsistent with accretionary incorporation of subducting ocean crust but rather suggest that episodic movement of the faults provided pathways for magma from the mantle into magma chambers. Late Paleozoic tectonic evolution of West Junggar involved Late Devonian to Carboniferous relative motion between the Junggar block and West Junggar ocean basin, which triggered the left-slip fault zones within a remnant ocean basin, along which the oceanic crust was disrupted to form linear ophiolitic melanges. Final filling of this remnant ocean basin and its dismemberment by strike-slip faulting occurred in the late Carboniferous, followed by crustal thickening by juvenile granites at the Carboniferous-Permian boundary.

Early Carboniferous collision of the Kalamaili orogenic belt, North Xinjiang, and its implications: Evidence from molasse deposits

Abstract: The age of the Kalamaili orogenic belt, marking the final amalgamation in East Junggar, North Xinjiang, is significant for the reconstruction of Paleozoic evolution of the southern Central Asian orogenic belt. The Tamugang and Songkarsu Formations of terrestrial molasse in the southeastern part of the Kalamaili belt, shed from the rising Kalamaili orogen, record the orogenic history. The strata consist of proximal conglomerate thinning to distal fine-grained sandstone and mudstone. Poorly sorted conglomerate is composed of dominant pyroclastic rocks with lesser andesitic, granitic, and ophiolitic clasts. Imbricated clasts indicate that the paleocurrents were directed to the present-day southwest to west-southwest. Laser ablation inductively coupled plasma–mass spectrometry (LA-ICP-MS) detrital zircon U-Pb dating of sandstones from both formations confirms that the Yemaquan arc northeast of the Kalamaili orogenic belt was the main source. Two granitic cobbles with zircon sensitive high-resolution ion microprobe (SHRIMP) U-Pb ages of 432.2 ± 7.8 Ma and 428.1 ± 6.8 Ma indicate the presence of Silurian magmatism in the Yemaquan arc. The SHRIMP U-Pb age of volcanic rocks from the Batamayineishan Formation, which overlies the molasse on both sides of the Kalamaili belt, is 349.5 ± 6.0 Ma. The depositional age of molasse is confined to between 343.5 Ma and 345 Ma, based on the 2 σ range of possible ages for the youngest detrital zircons and the overlying volcanic rocks. Combined with the previously dated plagiogranite and biostratigraphic ages on chert in the Kalamaili ophiolite as the lower age limit, the Kalamaili collision is restricted to 373.8–343.5 Ma, taking into account 2 σ error, suggesting that the termination of Kalamaili paleo-ocean subduction and the final amalgamation in East Junggar occurred before the Visean.

Kepler observations of rapidly oscillating Ap, δ Scuti and γ Doradus pulsations in Ap stars

Abstract: Observations of the A5p star KIC 8677585 obtained during the Kepler 10-d commissioning run with 1-min time resolution show that it is a rapidly oscillating Ap (roAp) star with several frequencies with periods near 10 min. In addition, a low frequency at 3.142 d −1 is also clearly present. Multiperiodic γ Doradus (γ Dor) and δ Scuti (δ Sct) pulsations, never before seen in any Ap star, are present in Kepler observations of at least three other Ap stars. Since γ Dor pulsations are seen in Ap stars, it is likely that the low frequency in KIC 8677585 is also a γ Dor pulsation. The simultaneous presence of both γ Dor and roAp pulsations and the unexpected detection of δ Sct and γ Dor pulsations in Ap stars present new opportunities and challenges for the interpretation of these stars. Since it is easy to confuse Am and Ap stars at classification dispersions, the nature of these Ap stars in the Kepler field needs to be confirmed.