This paper tests the hypothesis that the ongoing restructuring process in the European electricity sector has led to a common European market for electricity. Based on a Principal Component Analysis (PCA) of wholesale...
详细信息
This paper tests the hypothesis that the ongoing restructuring process in the European electricity sector has led to a common European market for electricity. Based on a Principal Component Analysis (PCA) of wholesale electricity prices in 2002-2006, we reject the assumption of full market integration. For several pairs of countries, the weaker hypothesis of (bilateral) convergence is accepted based on unit root tests (KPSS and ADF) and a convergence test based on filtered pairwise price relations. This indicates that the efforts to develop a single European market for electricity were so far only partially successful. We show that the daily auction prices of scarce cross-border transmission capacities are insufficient to explain the persistence of international price differentials. Empirically, our findings confirm the insufficiency of explicit capacity auctions as stated in the theoretical literature. (c) 2007 Elsevier B.V. All rights reserved.
OBJECTIVES The aim of this study was to assess cusp symmetry and coronary ostial eccentricity and its impact on coronary access following transcatheter aortic valve replacement (TAVR) using a patient-specific commissu...
详细信息
OBJECTIVES The aim of this study was to assess cusp symmetry and coronary ostial eccentricity and its impact on coronary access following transcatheter aortic valve replacement (TAVR) using a patient-specific commissural alignment implantation technique. BACKGROUND TAVR implantation techniques to obtain neocommissural alignment have been introduced. The impact of cusp symmetry and coronary ostial eccentricity on coronary access after TAVR remains unknown. METHODS Cardiac computed tomographic scans from 200 tricuspid aortic valves (TAVs) and 200 type 1 bicuspid aortic valves (BAVs) were studied. Cusp symmetry and coronary ostial eccentricity were assessed. In addition, the right coronary cusp/left coronary cusp and right coronary artery (RCA)/left coronary artery (LCA) ostia overlap views were calculated and compared. RESULTS Severe cusp asymmetry (>135 degrees) was more frequent in BAVs (52.5%) than in TAVs (2.5%) (P < 0.001), with the noncoronary cusp being the most common dominant cusp. The RCA ostium was found to be more often eccentric (>20 degrees) than the LCA ostium (28% vs 6%, respectively;P < 0.001). Considering the right/left cusp overlap view, there was <20 degrees deviation between the right coronary cusp-left coronary cusp centered line and the RCA-LCA centered line in 95% of all patients (TAV, 97%;BAV, 93%). The right/left cusp and coronary ostia overlap view differed by <10 degrees and <20 degrees fluoroscopic angulation in 75% and 98% of all cases, respectively. CONCLUSIONS Using the right/left cusp overlap view to obtain commissural alignment in TAVR is also an effective approach to implant one of the transcatheter heart valve commissures in the near center between both coronary ostia in most TAVs and type 1 BAVs. Preprocedural CT assessment remains crucial to assess cusp symmetry and coronary ostial eccentricity. (C) 2022 by the American College of Cardiology Foundation.
Energy efficiency gains are advocated to be a plausible strategy to mitigate rising carbon emissions in the Indian transportation sector. This study, thus, estimates the energy efficiency across transportation modes i...
详细信息
Energy efficiency gains are advocated to be a plausible strategy to mitigate rising carbon emissions in the Indian transportation sector. This study, thus, estimates the energy efficiency across transportation modes in India for 2000-2014, employing the panel stochastic frontier approach. Further, the long-run effect of energy efficiency gains on carbon emissions is also examined by employing the panel fully modified least square (FMOLS) and panel dynamic ordinary least square (DOLS) estimators. The empirical findings indicate an inverted U-shaped trend in energy efficiency for land transportation and a substantial rise for air transportation with higher volatility. However, the trend in energy efficiency for water transportation only shows a minor uptick with nearly stable movement. The long-run effect reveals that a 1% increase in energy efficiency will reduce carbon emissions in the transportation sector by more than 1%, between 1.343 (FMOLS) and 1.665% (DOLS). Based on such findings, a few implications are discussed to achieve a low-carbon energy system.
The authors report on the study of quantum wires and dots near the surface of InSb that contain quasi-one-dimensional and zero-dimensional, i.e. discrete, electron systems. Both types of samples are derived from metal...
The authors report on the study of quantum wires and dots near the surface of InSb that contain quasi-one-dimensional and zero-dimensional, i.e. discrete, electron systems. Both types of samples are derived from metal-oxide-semiconductor devices and make it possible to tune the electron number by a gate voltage. The laterally confining potential leads to the formation of one-dimensional sub-bands and to discrete levels respectively. Both are examined by far-infrared resonance spectroscopy. In order to attain a sufficiently high absorptance they fabricated the wires and dots by holographic lithography in arrays on macroscopic areas. Resonance energies of about 10 meV due to the lateral quantisation are found to be comparatively large because of the low conduction band mass of InSb. In particular, the influence of the narrow-gap band structure of InSb and of the electron-electron interaction on the quantised levels is discussed.
暂无评论