High Temperature Electron Localization in dense He Gas

We report new accurate mesasurements of the mobility of excess electrons in high density Helium gas in extended ranges of temperature $[(26\leq T\leq 77) K ]$ and density $[ (0.05\leq N\leq 12.0) {atoms} \cdot {nm}^{-3}]$ to ascertain the effect of temperature on the formation and dynamics of localized electron states. The main result of the experiment is that the formation of localized states essentially depends on the relative balance of fluid dilation energy, repulsive electron-atom interaction energy, and thermal energy. As a consequence, the onset of localization depends on the medium disorder through gas temperature and density. It appears that the transition from delocalized to localized states shifts to larger densities as the temperature is increased. This behavior can be understood in terms of a simple model of electron self-trapping in a spherically symmetric square well.Comment: 23 pages, 13 figure

Simultaneous optical trapping and detection of atoms by microdisk resonators

We propose a scheme for simultaneously trapping and detecting single atoms near the surface of a substrate using whispering gallery modes of a microdisk resonator. For efficient atom-mode coupling, the atom should be placed within approximately 150nm from the disk. We show that a combination of red and blue detuned modes can form an optical trap at such distances while the backaction of the atom on the field modes can simultaneously be used for atom detection. We investigate these trapping potentials including van-der-Waals and Casimir-Polder forces and discuss corresponding atom detection efficiencies, depending on a variety of system parameters. Finally, we analyze the feasibility of nondestructive detection

Cavitation of Electrons Bubbles in Liquid Helium Below saturation Pressure

We have used a Hartree-type electron-helium potential together with a density functional description of liquid $^4$He and $^3$He to study the explosion of electron bubbles submitted to a negative pressure. The critical pressure at which bubbles explode has been determined as a function of temperature. It has been found that this critical pressure is very close to the pressure at which liquid helium becomes globally unstable in the presence of electrons. It is shown that at high temperatures the capillary model overestimates the critical pressures. We have checked that a commonly used and rather simple electron-helium interaction yields results very similar to those obtained using the more accurate Hartree-type interaction. We have estimated that the crossover temperature for thermal to quantum nucleation of electron bubbles is very low, of the order of 6 mK for $^4$He.Comment: 22 pages, 9 figure

Strong Interactions of Single Atoms and Photons near a Dielectric Boundary

Modern research in optical physics has achieved quantum control of strong interactions between a single atom and one photon within the setting of cavity quantum electrodynamics (cQED). However, to move beyond current proof-of-principle experiments involving one or two conventional optical cavities to more complex scalable systems that employ N >> 1 microscopic resonators requires the localization of individual atoms on distance scales < 100 nm from a resonator's surface. In this regime an atom can be strongly coupled to a single intracavity photon while at the same time experiencing significant radiative interactions with the dielectric boundaries of the resonator. Here, we report an initial step into this new regime of cQED by way of real-time detection and high-bandwidth feedback to select and monitor single Cesium atoms localized ~100 nm from the surface of a micro-toroidal optical resonator. We employ strong radiative interactions of atom and cavity field to probe atomic motion through the evanescent field of the resonator. Direct temporal and spectral measurements reveal both the significant role of Casimir-Polder attraction and the manifestly quantum nature of the atom-cavity dynamics. Our work sets the stage for trapping atoms near micro- and nano-scopic optical resonators for applications in quantum information science, including the creation of scalable quantum networks composed of many atom-cavity systems that coherently interact via coherent exchanges of single photons.Comment: 8 pages, 5 figures, Supplemental Information included as ancillary fil

Choice of outcomes and measurement instruments in randomised trials on eLearning in medical education: A systematic mapping review protocol

Background: There will be a lack of 18 million healthcare workers by 2030. Multiplying the number of well-trained healthcare workers through innovative ways such as eLearning is highly recommended in solving this shortage. However, high heterogeneity of learning outcomes in eLearning systematic reviews reveals a lack of consistency and agreement on core learning outcomes in eLearning for medical education. In addition, there seems to be a lack of validity evidence for measurement instruments used in these trials. This undermines the credibility of these outcome measures and affects the ability to draw accurate and meaningful conclusions. The aim of this research is to address this issue by determining the choice of outcomes, measurement instruments and the prevalence of measurement instruments with validity evidence in randomised trials on eLearning for pre-registration medical education. Methods: We will conduct a systematic mapping and review to identify the types of outcomes, the kinds of measurement instruments and the prevalence of validity evidence among measurement instruments in eLearning randomised controlled trials (RCTs) in pre-registration medical education. The search period will be from January 1990 until August 2017. We will consider studies on eLearning for health professionals' education. Two reviewers will extract and manage data independently from the included studies. Data will be analysed and synthesised according to the aim of the review. Discussion: Appropriate choice of outcomes and measurement tools is essential for ensuring high-quality research in the field of eLearning and eHealth. The results of this study could have positive implications for other eHealth interventions, including (1) improving quality and credibility of eLearning research, (2) enhancing the quality of digital medical education and (3) informing researchers, academics and curriculum developers about the types of outcomes and validity evidence for measurement instruments used in eLearning studies. The protocol aspires to assist in the advancement of the eLearning research field as well as in the development of high-quality healthcare professionals' digital education. Systematic review registration: PROSPERO CRD4201706842

Towards quantum computing with single atoms and optical cavities on atom chips

We report on recent developments in the integration of optical microresonators into atom chips and describe some fabrication and implementation challenges. We also review theoretical proposals for quantum computing with single atoms based on the observation of photons leaking through the cavity mirrors. The use of measurements to generate entanglement can result in simpler, more robust and scalable quantum computing architectures. Indeed, we show that quantum computing with atom-cavity systems is feasible even in the presence of relatively large spontaneous decay rates and finite photon detector efficiencies.Comment: 14 pages, 6 figure

Cardiovascular Events in Patients Received Combined Fibrate/Statin Treatment versus Statin Monotherapy: Acute Coronary Syndrome Israeli Surveys Data

The effect of combination of fibrate with statin on major adverse cardiovascular events (MACE) following acute coronary syndrome (ACS) hospitalization is unclear. The main aim of this study was to investigate the 30-day rate of MACE in patients who participated in the nationwide ACS Israeli Surveys (ACSIS) and were treated on discharge with a fibrate (mainly bezafibrate) and statin combination vs. statin alone.The study population comprised 8,982 patients from the ACSIS 2000, 2002, 2004, 2006, 2008 and 2010 enrollment waves who were alive on discharge and received statin. Of these, 8,545 (95%) received statin alone and 437 (5%) received fibrate/statin combination. MACE was defined as a composite measure of death, recurrent MI, recurrent ischemia, stent thrombosis, ischemic stroke and urgent revascularization.Patients from the combination group were younger (58.1±11.9 vs. 62.9±12.6 years). However, they had significantly more co-morbidities (hypertension, diabetes), current smokers and unfavorable cardio-metabolic profiles (with respect to glucose, total cholesterol, triglyceride and HDL-cholesterol). Development of MACE was recorded in 513 (6.0%) patients from the statin monotherapy group vs. 13 (3.2%) from the combination group, p = 0.01. 30-day re-hospitalization rate was significantly lower in the combination group: 68 (15.6%) vs. 1691 (19.8%) of patients, respectively; p = 0.03. Multivariable analysis identified the fibrate/statin combination as an independent predictor of reduced risk of MACE with odds ratio of 0.54, 95% confidence interval 0.32–0.94.A significantly lower risk of 30-day MACE rate was observed in patients receiving combined fibrate/statin treatment following ACS compared with statin monotherapy. However, caution should be exercised in interpreting these findings taking into consideration baseline differences between our observational study groups

A 10 year case study on the changing determinants of University student satisfaction in the UK

Higher Education (HE), once the prerogative of a tiny elite, is now accessible to larger numbers of people around the world than ever before yet despite the fact that an understanding of student satisfaction has never been more important for today’s universities, the concept remains poorly understood. Here we use published data from the UK’s National Student Survey (NSS), representing data from 2.3 million full-time students collected from 2007 to 2016, as a case study of the benefits and limitations of measuring student satisfaction that might have applicability for other countries, particularly those that, like the UK, have experienced significant growth in student numbers. The analyses showed that the factor structure of the NSS remained generally stable and that the ability of the NSS to discriminate between different subjects at different universities actually improved over the ten-year sample period. The best predictors of overall satisfaction were 'Teaching Quality' and 'Organisation & Management', with 'Assessment & Feedback' having relatively weak predictive ability, despite the sector's tangible efforts to improve on this metric. The tripling of student fees in 2012 for English students (but not the rest of the UK) was used as a ‘natural experiment’ to investigate the sensitivity of student satisfaction ratings to the real economic costs of HE. The tuition fee increase had no identifiable negative effect, with student satisfaction steadily improving throughout the decade. Although the NSS was never designed to measure perceived value-for money, its insensitivity to major changes in the economic costs of HE to the individual suggest that the conventional concept of student satisfaction is incomplete. As such we propose that the concept of student satisfaction: (i) needs to be widened to take into account the broader economic benefits to the individual student by including measures of perceived value-for-money and (ii) should measure students’ level of satisfaction in the years post-graduation, by which time they may have a greater appreciation of the value of their degree in the workplace