Total Angular Momentum Conservation During Tunnelling through Semiconductor Barriers

We have investigated the electrical transport through strained p-Si/Si_{1-x}Ge_x double-barrier resonant tunnelling diodes. The confinement shift for diodes with different well width, the shift due to a central potential spike in a well, and magnetotunnelling spectroscopy demonstrate that the first two resonances are due to tunnelling through heavy hole levels, whereas there is no sign of tunnelling through the first light hole state. This demonstrates for the first time the conservation of the total angular momentum in valence band resonant tunnelling. It is also shown that conduction through light hole states is possible in many structures due to tunnelling of carriers from bulk emitter states.Comment: 4 pages, 4 figure

New Antarctic gravity anomaly grid for enhanced geodetic and geophysical studies in Antarctica

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne, and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated leveling of the different gravity data sets with respect to an Earth gravity model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth gravity models to be derived and represent a major step forward toward solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica

Progress report no. 5

Includes bibliographical referencesProgress report; June 30, 1974U.S. Atomic Energy Commission contract AT(11-1)225

Progress report no. 4

Statement of responsibility on title-page reads: editors: M.J. Driscoll, D.D. Lanning, I. Kaplan, A.T. Supple ; contributors: A. Alvim, G.J. Brown, J.K. Chan, T.P. Choong, M.J. Driscoll, G. A. Ducat, I.A. Forbes, M.V. Gregory, S.Y. Ho, C.M. Hove, O. K. Kadiroglu, R.J. Kennerley, D.D. Lanning, J.L. Lazewatsky, L. Lederman, A.S. Leveckis, V.A. Miethe, P. A. Scheinert, A.M. Thompson, N.E. Todreas, C.P. Tzanos, and P.J. WoodIncludes bibliographical referencesProgress report; June 30, 1973U.S. Atomic Energy Commission contract: AT(11-1)225

Advancing geodynamic research in Antarctica: reprocessing GNSS data to infer consistent coordinate time series (GIANT-REGAIN)

\ua9 Author(s) 2025. For nearly 3 decades, geodetic Global Navigation Satellite System (GNSS) measurements in Antarctica have provided direct observations of bedrock displacement, which is linked to various geodynamic processes, including plate motion, post-seismic deformation, and glacial isostatic adjustment (GIA). Previous geodynamic studies in Antarctica, especially those pertaining to GIA, have been constrained by the limited availability of GNSS data. This is due to the fact that GNSS data are collected by a wide range of institutions and network operators, with the raw observational data either not publicly available or scattered across various repositories. Further, the metadata necessary for rigorous data processing have often not been available or reliable. Consequently, the potential of GNSS observations for geodynamic studies in Antarctica has not been fully exploited yet. Here, we present consistently processed coordinate time series for GNSS sites in Antarctica and the sub-Antarctic region for the time span from 1995 to 2021. The data set is composed of 286 continuous and episodic sites, with 258 sites having a time span longer than 3 years. The coordinate time series were obtained from a combination of four independent processing solutions using different GNSS software and products, allowing the identification of inconsistencies in individual solutions. From these, we infer a reliable and robust combined solution. A key issue was the thorough reassessment of station metadata to minimise artefacts and biases in the coordinate time series. The resulting data set provides coordinate time series with unprecedented spatiotemporal coverage, promising significant advancements in future geodynamic studies in Antarctica. The data set is freely available at https://doi.org/10.1594/PANGAEA.967515 (Buchta et al., 2024a)

AMS INSIGHT—Absorbable Metal Stent Implantation for Treatment of Below-the-Knee Critical Limb Ischemia: 6-Month Analysis

Endoluminal treatment of infrapopliteal artery lesions is a matter of controversy. Bioabsorbable stents are discussed as a means to combine mechanical prevention of vessel recoil with the advantages of long-term perspectives. The possibility of not having a permanent metallic implant could permit the occurrence of positive remodeling with lumen enlargement to compensate for the development of new lesions. The present study was designed to investigate the safety of absorbable metal stents (AMSs) in the infrapopliteal arteries based on 1- and 6-month clinical follow-up and efficacy based on 6-month angiographic patency. One hundred seventeen patients with 149 lesions with chronic limb ischemia (CLI) were randomized to implantation of an AMS (60 patients, 74 lesions) or stand-alone percutaneous transluminal angioplasty (PTA; 57 patients, 75 lesions). Seven PTA-group patients “crossed over” to AMS stenting. The study population consisted of patients with symptomatic CLI (Rutherford categories 4 and 5) and de novo stenotic (>50%) or occlusive atherosclerotic disease of the infrapopliteal arteries who presented with a reference diameter of between 3.0 and 3.5 mm and a lesion length of <15 mm. The primary safety endpoint was defined as absence of major amputation and/or death within 30 days after index intervention and the primary efficacy endpoint was the 6-month angiographic patency rate as confirmed by core-lab quantitative vessel analysis. The 30-day complication rate was 5.3% (3/57) and 5.0% (3/60) in patients randomized for PTA alone and PTA followed by AMS implantation, respectively. On an intention-to-treat basis, the 6-month angiographic patency rate for lesions treated with AMS (31.8%) was significantly lower (p = 0.013) than the rate for those treated with PTA (58.0%). Although the present study indicates that the AMS technology can be safely applied, it did not demonstrate efficacy in long-term patency over standard PTA in the infrapopliteal vessels

ZILVERPASS Study: ZILVER PTX Stent versus Prosthetic Above-the-Knee Bypass Surgery in Femoropopliteal Lesions, 5-year Results

Purpose: To report the 60-month safety and effectiveness results of a multicenter, prospective, randomized controlled trial comparing the ZILVER PTX paclitaxel-eluting stent to prosthetic above-the-knee bypass for the treatment of symptomatic TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions. Materials and methods: Patients were enrolled between October 2013 and July 2017. One of the secondary outcomes was primary patency at 60&nbsp;months, defined as no evidence of binary restenosis or occlusion within the target lesion or bypass graft based on a duplex ultrasound peak systolic velocity ratio &lt; 2.4 and no clinically-driven target lesion revascularization (TLR) in endovascular cases or reintervention to restore flow in the bypass at 60&nbsp;months. Survival rates after 5&nbsp;years were also analyzed. Results: 220 patients (mean age 68.6 ± 10.5&nbsp;years; 159 men) were included and randomized to ZILVER PTX (n = 113, 51.40%) or BYPASS group (n = 107, 48.60%). The 60-month primary patency rate was 49.3% for the ZILVER PTX group versus 40.7% for the bypass group (p = 0.6915). Freedom from TLR was 63.8% for the ZILVER PTX group versus 52.8% for the bypass group (p = 0.2637). At 5&nbsp;years, no significant difference in survival rate could be seen between the ZILVER PTX and the bypass group (69.1% vs. 71% respectively, p = 0.5503). Conclusion: Even at 5&nbsp;years, non-inferior safety and effectiveness results of the ZILVER PTX could be seen. These findings confirmed that the use of ZILVER PTX stents can be considered as a valid alternative for bypass surgery when treating long and complex femoropopliteal lesions. Graphical Abstract: [Figure not available: see fulltext.

Advancing geodynamic research in Antarctica: reprocessing GNSS data to infer consistent coordinate time series (GIANT-REGAIN)

For nearly 3 decades, geodetic Global Navigation Satellite System (GNSS) measurements in Antarctica have provided direct observations of bedrock displacement, which is linked to various geodynamic processes, including plate motion, post-seismic deformation, and glacial isostatic adjustment (GIA). Previous geodynamic studies in Antarctica, especially those pertaining to GIA, have been constrained by the limited availability of GNSS data. This is due to the fact that GNSS data are collected by a wide range of institutions and network operators, with the raw observational data either not publicly available or scattered across various repositories. Further, the metadata necessary for rigorous data processing have often not been available or reliable. Consequently, the potential of GNSS observations for geodynamic studies in Antarctica has not been fully exploited yet. Here, we present consistently processed coordinate time series for GNSS sites in Antarctica and the sub-Antarctic region for the time span from 1995 to 2021. The data set is composed of 286 continuous and episodic sites, with 258 sites having a time span longer than 3 years. The coordinate time series were obtained from a combination of four independent processing solutions using different GNSS software and products, allowing the identification of inconsistencies in individual solutions. From these, we infer a reliable and robust combined solution. A key issue was the thorough reassessment of station metadata to minimise artefacts and biases in the coordinate time series. The resulting data set provides coordinate time series with unprecedented spatiotemporal coverage, promising significant advancements in future geodynamic studies in Antarctica. The data set is freely available at https://doi.org/10.1594/PANGAEA.967515 (Buchta et al., 2024a).</p