521 research outputs found
In-situ spectroscopy of intrinsic Bi2Te3 topological insulator thin films and impact of extrinsic defects
Combined in-situ x-ray photoemission spectroscopy, scanning tunnelling
spectroscopy and angle resolved photoemission spectroscopy of molecular beam
epitaxy grown Bi2Te3 on lattice mismatched substrates reveal high quality
stoichiometric thin films with topological surface states without a
contribution from the bulk bands at the Fermi energy. The absence of bulk
states at the Fermi energy is achieved without counter doping. We observe that
the surface morphology and electronic band structure of Bi2Te3 are not affected
by in-vacuo storage and exposure to oxygen, whereas major changes are observed
when exposed to ambient conditions. These films help define a pathway towards
intrinsic topological devices.Comment: 8 pages, 5 figure
LCrowdV: Generating Labeled Videos for Simulation-based Crowd Behavior Learning
We present a novel procedural framework to generate an arbitrary number of
labeled crowd videos (LCrowdV). The resulting crowd video datasets are used to
design accurate algorithms or training models for crowded scene understanding.
Our overall approach is composed of two components: a procedural simulation
framework for generating crowd movements and behaviors, and a procedural
rendering framework to generate different videos or images. Each video or image
is automatically labeled based on the environment, number of pedestrians,
density, behavior, flow, lighting conditions, viewpoint, noise, etc.
Furthermore, we can increase the realism by combining synthetically-generated
behaviors with real-world background videos. We demonstrate the benefits of
LCrowdV over prior lableled crowd datasets by improving the accuracy of
pedestrian detection and crowd behavior classification algorithms. LCrowdV
would be released on the WWW
Safety and Tolerability of Sodium Thiosulfate in Patients with an Acute Coronary Syndrome Undergoing Coronary Angiography:A Dose-Escalation Safety Pilot Study (SAFE-ACS)
Background. In animal studies, hydrogen sulfide (H2S) has been shown to protect the heart from ischemia-reperfusion injury. This study evaluates the safety and tolerability of the H2S donor sodium thiosulfate (STS) in patients with acute coronary syndrome (ACS). Methods. Eighteen patients, undergoing coronary angiography for ACS, received STS intravenously immediately after arrival at the catheterization laboratory according to a “3 + 3 dose-escalation design” with fixed dosing endpoint (0, 2.5, 5, 10, 12.5, and 15 grams). This first dose STS was combined with verapamil and nitroglycerin required for transradial procedures. A second dose STS was administered 6 hours later. Primary endpoint was dose-limiting toxicity, defined as significant hemodynamic instability or death up to 24 hours or before discharge from the coronary care unit. Secondary outcomes included the occurrence of anaphylaxis, nausea, vomiting, and systolic blood pressure (SBP) course. Results. Sixteen patients received two dosages of STS and two patients one dosage. None of the patients reached the primary endpoint, nor experienced a serious adverse event. We observed a clinically well-tolerated decline in SBP 1 hour after administration of the first STS dose and concomitant verapamil/nitroglycerin. SBP for all patients together reduced 16.8 (8.1–25.5) mmHg (P=0.0008). No significant decline in SBP occurred after the second dose. Mild nausea was observed in one patient. Conclusion. This is the first report on sodium thiosulfate administration in patients with acute coronary syndromes. Our data suggest that sodium thiosulfate was well tolerated in this setting. The potential benefit of this intervention has to be examined in larger studies
Effects of Supersymmetric Threshold Corrections on High-Scale Flavor Textures
Integration of superpartners out of the spectrum induces potentially large
contributions to Yukawa couplings. These corrections, the supersymmetric
threshold corrections, therefore influence the CKM matrix prediction in a
non-trivial way. We study effects of threshold corrections on high-scale flavor
structures specified at the gauge coupling unification scale in supersymmetry.
In our analysis, we first consider high-scale Yukawa textures which qualify
phenomenologically viable at tree level, and find that they get completely
disqualified after incorporating the threshold corrections. Next, we consider
Yukawa couplings, such as those with five texture zeroes, which are incapable
of explaining flavor-changing proceses. Incorporation of threshold corrections,
however, makes them phenomenologically viable textures. Therefore,
supersymmetric threshold corrections are found to leave observable impact on
Yukawa couplings of quarks, and any confrontation of high-scale textures with
experiments at the weak scale must take into account such corrections.Comment: 25 pages, submitted to JHE
Using paired teaching for earthquake education in schools
In this study, we have created 10 geoscience video lessons that follow the paired-teaching pedagogical approach. This method is used to supplement the standard school curriculum with video lessons, instructed by geoscientists from around the world, coupled with activities carried out under the guidance of classroom teachers. The video lessons introduce students to the scientific concepts behind earthquakes (e.g. the Earth's interior, plate tectonics, faulting, and seismic energy), earthquake hazards, and mitigation measures (e.g. liquefaction, structural, and non-structural earthquake hazards). These concepts are taught through hands-on learning, where students use everyday materials to build models to visualize basic Earth processes that produce earthquakes and explore the effects of different hazards. To evaluate the effectiveness of these virtual lessons, we tested our videos in school classrooms in Dushanbe (Tajikistan) and London (United Kingdom). Before and after the video implementations, students completed questionnaires that probed their knowledge on topics covered by each video, including the Earth's interior, tectonic plate boundaries, and non-structural hazards.
Our assessment results indicate that, while the paired-teaching video lessons appear to enhance student knowledge and understanding of some concepts (e.g. Earth's interior, earthquake location forecasting, and non-structural hazards), they bring little change to their views on the causes of earthquakes and their relation to plate boundaries. In general, the difference between UK and Tajik students' level of knowledge prior to and after video testing is more significant than the difference between pre- and post-knowledge for each group. This could be due to several factors affecting curriculum testing (e.g. level of teachers' participation and classroom culture) and students' learning of content (e.g. pre-existing hazards knowledge and experience). To maximize the impact of school-based risk reduction education, curriculum developers must move beyond innovative content and pedagogical approaches, take classroom culture into consideration, and instil skills needed for participatory learning and discovery
Сочетание криогенного и лучевого воздействий в лечении больных распространенными и рецидивными формами рака кожи головы и шеи
Grupul de autori a elaborat o metodă de tratament al pacienţilor cu cancer cutanat infi ltrativ, ce constă din radioterapie şi criochirurgie în diferite variante de asociere.Сочетание криогенного и лучевого воздействий в лечении больных распространенными и рецидивными формами рака кожи головы и ше
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