Universal phase shift and non-exponential decay of driven single-spin oscillations

We study, both theoretically and experimentally, driven Rabi oscillations of a single electron spin coupled to a nuclear spin bath. Due to the long correlation time of the bath, two unusual features are observed in the oscillations. The decay follows a power law, and the oscillations are shifted in phase by a universal value of ~pi/4. These properties are well understood from a theoretical expression that we derive here in the static limit for the nuclear bath. This improved understanding of the coupled electron-nuclear system is important for future experiments using the electron spin as a qubit.Comment: Main text: 4 pages, 3 figures, Supplementary material: 2 pages, 3 figure

Equipment specification for a space rated radar altimeter Final technical report

Equipment specifications for GEOS C mission altimeter

Developing a Critical Understanding of Smart Urbanism?

Smart urbanism is emerging at the intersection of visions for the future of urban places, new technologies and infrastructures. Smart urbanism discourses are deeply rooted in seductive and normative visions of the future where digital technology stands as the primary driver for change. Yet our understanding of the opportunities, challenges, and implications of smart urbanism is limited. Research in this field is in its infancy, fragmented along disciplinary lines and often based on single city case studies. As a result, we lack both the theoretical insight and empirical evidence required to assess the implications of this potentially transformative phenomenon. Given the significant implications of smart urbanism there is an urgent need to critically engage with why, how, for whom and with what consequences smart urbanism is emerging in different urban contexts. The aim of this review is to unpack the different logics and rationales behind smart urbanism discourses and proposals, and in this way understand the ways by which imaginaries of urban futures are currently being constructed, along with their socio-technical and political implications for future research priorities

Driven coherent oscillations of a single electron spin in a quantum dot

The ability to control the quantum state of a single electron spin in a quantum dot is at the heart of recent developments towards a scalable spin-based quantum computer. In combination with the recently demonstrated exchange gate between two neighbouring spins, driven coherent single spin rotations would permit universal quantum operations. Here, we report the experimental realization of single electron spin rotations in a double quantum dot. First, we apply a continuous-wave oscillating magnetic field, generated on-chip, and observe electron spin resonance in spin-dependent transport measurements through the two dots. Next, we coherently control the quantum state of the electron spin by applying short bursts of the oscillating magnetic field and observe about eight oscillations of the spin state (so-called Rabi oscillations) during a microsecond burst. These results demonstrate the feasibility of operating single-electron spins in a quantum dot as quantum bits.Comment: Total 25 pages. 11 pages main text, 5 figures, 9 pages supplementary materia

The EFSUMB Guidelines and Recommendations for the Clinical Practice of Elastography in Non-Hepatic Applications: Update 2018

This manuscript describes the use of ultrasound elastography, with the exception of liver applications, and represents an update of the 2013 EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) Guidelines and Recommendations on the clinical use of elastography

Prevalence of gastro-oesophageal reflux disease symptoms and reflux-associated respiratory symptoms in asthma

<p>Abstract</p> <p>Background</p> <p>Gastro-oesophageal reflux disease (GORD) symptoms are common in asthma and have been extensively studied, but less so in the Asian continent. Reflux-associated respiratory symptoms (RARS) have, in contrast, been little-studied globally. We report the prevalence of GORD symptoms and RARS in adult asthmatics, and their association with asthma severity and medication use.</p> <p>Methods</p> <p>A cross-sectional analytical study. A validated interviewer-administered GORD scale was used to assess frequency and severity of seven GORD symptoms. Subjects were consecutive asthmatics attending medical clinics. Controls were matched subjects without respiratory symptoms.</p> <p>Results</p> <p>The mean (SD) composite GORD symptom score of asthmatics was significantly higher than controls (21.8 (17.2) versus 12.0 (7.6); <it>P </it>< 0.001) as was frequency of each symptom and RARS. Prevalence of GORD symptoms in asthmatics was 59.4% (95% CI, 59.1%-59.6%) versus 28.5% in controls (95% CI, 29.0% - 29.4%). 36% of asthmatics experienced respiratory symptoms in association with both typical and atypical GORD symptoms, compared to 10% of controls (<it>P </it>< 0.001). An asthmatic had a 3.5 times higher risk of experiencing a GORD symptom after adjusting for confounders (OR 3.5; 95% CI 2.5-5.3). Severity of asthma had a strong dose-response relationship with GORD symptoms. Asthma medication use did not significantly influence the presence of GORD symptoms.</p> <p>Conclusions</p> <p>GORD symptoms and RARS were more prevalent in a cohort of Sri Lankan adult asthmatics compared to non-asthmatics. Increased prevalence of RARS is associated with both typical and atypical symptoms of GORD. Asthma disease and its severity, but not asthma medication, appear to influence presence of GORD symptoms.</p

Graduates

https://thekeep.eiu.edu/commencement_fall2015/1029/thumbnail.jp

Locking electron spins into magnetic resonance by electron-nuclear feedback

The main obstacle to coherent control of two-level quantum systems is their coupling to an uncontrolled environment. For electron spins in III-V quantum dots, the random environment is mostly given by the nuclear spins in the quantum dot host material; they collectively act on the electron spin through the hyperfine interaction, much like a random magnetic field. Here we show that the same hyperfine interaction can be harnessed such that partial control of the normally uncontrolled environment becomes possible. In particular, we observe that the electron spin resonance frequency remains locked to the frequency of an applied microwave magnetic field, even when the external magnetic field or the excitation frequency are changed. The nuclear field thereby adjusts itself such that the electron spin resonance condition remains satisfied. General theoretical arguments indicate that this spin resonance locking is accompanied by a significant reduction of the randomness in the nuclear field.Comment: 6 pages, 5 figures, 4 pages supplementary materia

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice

Lifestyle factors affecting gastroesophageal reflux disease symptoms: a cross-sectional study of healthy 19864 adults using FSSG scores

<p>Abstract</p> <p>Background</p> <p>Gastroesophageal reflux disease (GERD) is a very common disorder worldwide, comprised of reflux esophagitis (RE) and non-erosive reflux disease (NERD). As more than half of GERD patients are classified into the NERD group, precise evaluation of bothersome epigastric symptoms is essential. Nevertheless, compared with many reports targeting endoscopic reflux esophagitis, large-scale studies focusing on GERD symptoms have been very scarce.</p> <p>Methods</p> <p>To elucidate lifestyle factors affecting GERD symptoms, 19,864 healthy adults in Japan were analyzed. Sub-analyses of 371 proton pump inhibitor (PPI) users and 539 histamine H₂-receptor antagonist (H₂RA) users were also performed. Using the FSSG (Frequency Scale for the Symptoms of GERD) score as a response variable, 25 lifestyle-related factors were univariately evaluated by Student's <it>t</it>-test or Pearson's correlation coefficient, and were further analyzed with multiple linear regression modelling.</p> <p>Results</p> <p>Average FSSG scores were 4.8 ± 5.2 for total subjects, 9.0 ± 7.3 for PPI users, and 8.2 ± 6.6 for H₂RA users. Among the total population, positively correlated factors and standardized coefficients (β) for FSSG scores are inadequate sleep (β = 0.158), digestive drug users (β = 0.0972 for PPI, β = 0.0903 for H₂RA, and β = 0.104 for others), increased body weight in adulthood (β = 0.081), dinner just before bedtime (β = 0.061), the habit of midnight snack (β = 0.055), lower body mass index (β = 0.054), NSAID users (β = 0.051), female gender (β = 0.048), lack of breakfast (β = 0.045), lack of physical exercise (β = 0.035), younger age (β = 0.033), antihyperglycemic agents non-users (β = 0.026), the habit of quick eating (β = 0.025), alcohol drinking (β = 0.025), history of gastrectomy (β = 0.024), history of cardiovascular disease (β = 0.020), and smoking (β = 0.018). Positively correlated factors for PPI users are female gender (β = 0.198), inadequate sleep (β = 0.150), lack of breakfast (β = 0.146), antihypertensive agent non-users (β = 0.134), and dinner just before bedtime (β = 0.129), whereas those for H₂RA users are inadequate sleep (β = 0.248), habit of midnight snack (β = 0.160), anticoagulants non-users (β = 0.106), and antihypertensive agents non-users (β = 0.095).</p> <p>Conclusions</p> <p>Among many lifestyle-related factors correlated with GERD symptoms, poor quality of sleep and irregular dietary habits are strong risk factors for high FSSG scores. At present, usual dose of PPI or H₂RA in Japan cannot fully relieve GERD symptoms.</p