Static Charge Density Wave Order in the Superconducting State of La2-xBaxCuO4

Charge density wave (CDW) correlations feature prominently in the phase diagram of the cuprates, motivating competing theories of whether fluctuating CDW correlations aid superconductivity or whether static CDW order coexists with superconductivity in inhomogeneous or spatially modulated states. Here we report Cu $L$-edge resonant x-ray photon correlation spectroscopy (XPCS) measurements of CDW correlations in superconducting La$_{2-x}$Ba$_x$CuO$_4$ $x=0.11$. Static CDW order is shown to exist in the superconducting state at low temperatures and to persist up to at least 85\% of the CDW transition temperature. We discuss the implications of our observations for how \emph{nominally} competing order parameters can coexist in the cuprates.Comment: 6 pages, 5 figures, Accepted in Phys. Rev. B Rapid Communication

Capturing the wisdom of the crowd: health professions’ educators meet at a virtual world café

Background: Conversations about educational challenges and potential solutions among a globally and culturally diverse group of health professions’ educators can facilitate identity formation, mentoring relationships and professional network building. The COVID-19 pandemic has made it even more important to co-create and disseminate knowledge, specifically regarding online and flexible learning formats. Approach: Based on the principles of social learning, we combined speed mentoring and world café formats to offer a virtual Zoom™ workshop, with large and small group discussions, to reach health professions’ educators across the globe. The goal was to establish a psychologically safe space for dialogue regarding adaptation to online teaching-learning formats. Evaluation: We aimed to establish psychological safety to stimulate thought-provoking discussions within the various small groups and obtain valuable contributions from participants. From these conversations, we were able to formulate ‘hot tips’ on how to adapt to (sometimes new) online teaching-learning formats while nurturing teacher and student wellbeing. Reflection: Through this virtual workshop we realized that despite contextual differences, many challenges are common worldwide. We experienced technological difficulties during the session, which needed rapid adaptation by the organising team. We encouraged, but did not pressure, participants to use video and audio during breakout discussions as we wanted them to feel safe and comfortable. The large audience size and different time zones were challenging; therefore, leadership had to be resilient and focussed. Although this virtual format was triggered by the pandemic, the format can be continued in the future to discuss other relevant global education topics

Skyrmion fluctuations at a first-order phase transition boundary

Magnetic skyrmions are topologically protected spin textures with promising prospects for applications in data storage. They can form a lattice state due to competing magnetic interactions and are commonly found in a small region of the temperature - magnetic field phase diagram. Recent work has demonstrated that these magnetic quasi-particles fluctuate at the μeV energy scale. Here, we use a coherent x-ray correlation method at an x-ray free-electron laser to investigate these fluctuations in a magnetic phase coexistence region near a first-order transition boundary where fluctuations are not expected to play a major role. Surprisingly, we find that the relaxation of the intermediate scattering function at this transition differs significantly compared to that deep in the skyrmion lattice phase. The observation of a compressed exponential behavior suggests solid-like dynamics, often associated with jamming. We assign this behavior to disorder and the phase coexistence observed in a narrow field-window near the transition, which can cause fluctuations that lead to glassy behavior

Wide Angle Polarization Analysis with Neutron Spin Filters

AbstractWe report substantial improvements in a compact wide angle neutron spin filter system that was recently employed on the Multi- Axis Crystal Spectrometer at the Center for Neutron Research at the U.S. National Institute of Standards and Technology. The apparatus consists of a cylindrical 3He polarizer cell and wide-angle 3He analyzer cells, a vertical solenoid to provide a uniform magnetic field, and a shielded radio-frequency solenoid for the polarizer cell. Nuclear magnetic resonance is employed to reverse the polarization in the polarizer cell and monitor the 3He polarization in all cells. The first experiment using this apparatus was carried out with cylindrical analyzer cells with limited angular coverage due to low polarizations in fused quartz cells. We present results for aluminosilicate glass analyzer cells that cover 110 ∘ and have long relaxation times (100h to 400h). Using two 100W diode bars spectrally narrowed with chirped volume Bragg gratings, we have obtained 65% - 80% 3He polarization in these cells. The 3He polarization has been measured by neutron transmission and electron paramagnetic resonance. Additional progress includes an improved holding field solenoid and decreased spin-flip losses

Twelve tips for organising speed mentoring events for healthcare professionals at small or large-scale venues

Mentors play a critical role in the development of professionals, influencing their job satisfaction, career aspirations and evolving professional identity. A variety of mentoring models exist, each with distinct benefits and challenges. Speed mentoring, based on the concept of speed dating, provides mentees with opportunities to meet multiple mentors over a short time and pose focussed career development questions. At large-scale events such as the annual AMEE (Association for Medical Education in Europe) meeting, speed mentoring sessions can successfully connect aspiring, novice and mid-career educators with international educational leaders to facilitate transfer of valuable insights for professional growth. For some mentors and mentees, this might spur ongoing communications or even longitudinal relationships. In this paper, we aim to provide strategies for planning and implementing speed mentoring events, combining insights gained from the literature and our experience of organising speed mentoring at the 2019 AMEE meeting in Vienna. These tips will be useful to a variety of professionals planning to organise speed mentoring initiatives

Distribution, diversity, length-weight relationship and recruitment pattern of deep-sea finfishes and shellfishes in the shelf-break area off southwest Indian EEZ

The results of an exclusive fishing cruise, No. 241, undertaken by FORV Sayar Sampada (Ministry of Earth Sciences) during January-February 2006, in the shelf-break area (500-1000m depth) in the southwest region of Indian EEZ (Lat.Q-16" and Long. 72"-75"46) are presented. Bottom trawling was conducted at 33 stations. A total catch of 1795 kg was realised, out of which the discards formed 31 1 kg. A variety of non-conventional finfishes (77 species) and shellfishes (shrimps 8 species, crabs 3 species, one species of lobsterette) have been recorded. Depth-wise 235m zone indicated the maximum catch. The total catch during the entire cruise was dominated by Psenopsis ryanra. The various population parameters such as La, K, total mortality (Z), natural mortality (M), fishing mortality (F), exploitation ratio (E), recruitment pattern and length-weight relationship of some of the important species have been worked out. In most of the deep-sea fishes, the recruitment appeared to take place almost throughout the year and showed great similarity among the various species except Luciobrotula bartschi. Presently, all these resources remain unexploited, except the shrimps. The trawlers based at Cochin, Quilon and Munambam have been exploiting the deep-sea shrimp resources like the red-ring Arbreus alcocki from the Quilon Bank and other similar areas of< west coast for the last five years. Interestingly Psenopsis cyanea has been found to occur as bye-catch in these fishing operations. Therefore, these two species showed higher fishing mortality compared to practically nil value in other finfishes and shellfishes. The occurrence of the deep-sea glass sponge, Hyalonema sp. off Mangalore is also reported. Bio-silica, extracted from this sponge, has a vide range of applications in the medical field from novel biomaterials for bone replacements to the stabilization of tissue. Most of the resources being nonconventional there is need to evolve new processing methods, product diversification and develop export avenues to make deep-sea fishing venture a success. Inventorisation of the deep-sea biodiversity and preparation of fishery atlas also merit serious consideration

From clinical educators to educational scholars and leaders: strategies for developing and advancing a career in health professions education

This toolbox article provides ideas and recommendations for academic and clinical educators seeking roles as educational scholars and leaders

An instrument for in situ time-resolved X-ray imaging and diffraction of laser powder bed fusion additive manufacturing processes

In situ X-ray-based measurements of the laser powder bed fusion (LPBF) additive manufacturing process produce unique data for model validation and improved process understanding. Synchrotron X-ray imaging and diffraction provide high resolution, bulk sensitive information with sufficient sampling rates to probe melt pool dynamics as well as phase and microstructure evolution. Here, we describe a laboratory-scale LPBF test bed designed to accommodate diffraction and imaging experiments at a synchrotron X-ray source during LPBF operation. We also present experimental results using Ti-6Al-4V, a widely used aerospace alloy, as a model system. Both imaging and diffraction experiments were carried out at the Stanford Synchrotron Radiation Lightsource. Melt pool dynamics were imaged at frame rates up to 4 kHz with a ∼1.1 μm effective pixel size and revealed the formation of keyhole pores along the melt track due to vapor recoil forces. Diffraction experiments at sampling rates of 1 kHz captured phase evolution and lattice contraction during the rapid cooling present in LPBF within a ∼50 × 100 μm area. We also discuss the utility of these measurements for model validation and process improvement