Methodological “Learning-by-Doing” for Action Design Research

This study shares the direct experiences of designing and implementing methodological “learning-by-doing” for Action Design Research (ADR) within a 5-credit module that condenses the realities of completing a full ADR project without compromising the rigour of the approach. The module is described in detail, along with the specifics of its implementation over two years and the key learnings from doing so. Adopting a confessional writing approach, documented experiences from those involved (both designers and students) provide a rich data source, analysed using autonomous and communicative reflexivity. The underlying contribution of this paper is that it provides insights into the learning of ADR, the doing of ADR, and the outcomes of a technique that simultaneously combines both. As a result, ADR educators and researchers can draw on these insights to further their teaching, learning, and research endeavours. Finally, key insights such as forced pragmatism and the challenge of problematisation add to our understanding of conducting ADR while avoiding issues such as methodological slurring

Imaging resonant dissipation from individual atomic defects in graphene

Conversion of electric current into heat involves microscopic processes that operate on nanometer length-scales and release minute amounts of power. While central to our understanding of the electrical properties of materials, individual mediators of energy dissipation have so far eluded direct observation. Using scanning nano-thermometry with sub-micro K sensitivity we visualize and control phonon emission from individual atomic defects in graphene. The inferred electron-phonon 'cooling power spectrum' exhibits sharp peaks when the Fermi level comes into resonance with electronic quasi-bound states at such defects, a hitherto uncharted process. Rare in the bulk but abundant at graphene's edges, switchable atomic-scale phonon emitters define the dominant dissipation mechanism. Our work offers new insights for addressing key materials challenges in modern electronics and engineering dissipation at the nanoscale

Unusual suppression of the superconducting energy gap and critical temperature in atomically thin NbSe2

It is well known that superconductivity in thin films is generally suppressed with decreasing thickness. This suppression is normally governed by either disorder-induced localization of Cooper pairs, weakening of Coulomb screening, or generation and unbinding of vortex-antivortex pairs as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. Defying general expectations, few-layer NbSe2 - an archetypal example of ultrathin superconductors - has been found to remain superconducting down to monolayer thickness. Here we report measurements of both the superconducting energy gap and critical temperature in high-quality monocrystals of few-layer NbSe2, using planar-junction tunneling spectroscopy and lateral transport. We observe a fully developed gap that rapidly reduces for devices with the number of layers N < 5, as does their ctitical temperature. We show that the observed reduction cannot be explained by disorder, and the BKT mechanism is also excluded by measuring its transition temperature that for all N remains very close to Tc. We attribute the observed behavior to changes in the electronic band structure predicted for mono- and bi- layer NbSe2 combined with inevitable suppression of the Cooper pair density at the superconductor-vacuum interface. Our experimental results for N > 2 are in good agreement with the dependences of the gap and Tc expected in the latter case while the effect of band-structure reconstruction is evidenced by a stronger suppression of the gap and the disappearance of its anisotropy for N = 2. The spatial scale involved in the surface suppression of the density of states is only a few angstroms but cannot be ignored for atomically thin superconductors.Comment: 21 pages, including supporting informatio

Visualizing Poiseuille flow of hydrodynamic electrons

Hydrodynamics is a general description for the flow of a fluid, and is expected to hold even for fundamental particles such as electrons when inter-particle interactions dominate. While various aspects of electron hydrodynamics were revealed in recent experiments, the fundamental spatial structure of hydrodynamic electrons, the Poiseuille flow profile, has remained elusive. In this work, we provide the first real-space imaging of Poiseuille flow of an electronic fluid, as well as visualization of its evolution from ballistic flow. Utilizing a scanning nanotube single electron transistor, we image the Hall voltage of electronic flow through channels of high-mobility graphene. We find that the profile of the Hall field across the channel is a key physical quantity for distinguishing ballistic from hydrodynamic flow. We image the transition from flat, ballistic field profiles at low temperature into parabolic field profiles at elevated temperatures, which is the hallmark of Poiseuille flow. The curvature of the imaged profiles is qualitatively reproduced by Boltzmann calculations, which allow us to create a 'phase diagram' that characterizes the electron flow regimes. Our results provide long-sought, direct confirmation of Poiseuille flow in the solid state, and enable a new approach for exploring the rich physics of interacting electrons in real space

The Quantum Twisting Microscope

The invention of scanning probe microscopy has revolutionized the way electronic phenomena are visualized. While present-day probes can access a variety of electronic properties at a single location in space, a scanning microscope that can directly probe the quantum mechanical existence of an electron at multiple locations would provide direct access to key quantum properties of electronic systems, so far unreachable. Here, we demonstrate a conceptually new type of scanning probe microscope - the Quantum Twisting Microscope (QTM) - capable of performing local interference experiments at its tip. The QTM is based on a unique van-der-Waals tip, allowing the creation of pristine 2D junctions, which provide a multitude of coherently-interfering paths for an electron to tunnel into a sample. With the addition of a continuously scanned twist angle between the tip and sample, this microscope probes electrons in momentum space similar to the way a scanning tunneling microscope probes electrons in real space. Through a series of experiments, we demonstrate room temperature quantum coherence at the tip, study the twist angle evolution of twisted bilayer graphene, directly image the energy bands of monolayer and twisted bilayer graphene, and finally, apply large local pressures while visualizing the evolution of the flat energy bands of the latter. The QTM opens the way for novel classes of experiments on quantum materials

A verification approach for crosscutting features based on extension join points

Recently, one arguing question in the context of product line development is how to improve the modularization and composition of crosscutting features. However, little attention has been paid to the closely related issue of testing the crosscutting features. This paper proposes a verification approach for the crosscutting features of a product line based on the use of a previously proposed concept called Extension Join Points

A prospective multicenter observational study assessing incidence and risk factors for acute blood transfusion reactions in dogs

BACKGROUND: Reported incidence of blood transfusion reactions (TR) varies greatly.OBJECTIVE: To prospectively evaluate the incidence of acute TRs in dogs receiving allogenic blood products, using consensus definitions, and to assess factors associated with TRs.ANIMALS: Dogs (n = 858) administered allogenic blood products (n = 1542) between March and November 2022.METHODS: Prospective, multicenter surveillance study occurring in referral hospitals in the United States, United Kingdom, and Australia recording TRs in dogs administered blood products as defined by the consensus guidelines published by The Association of Veterinary Hematology and Transfusion Medicine in 2021.RESULTS: The incidence of acute TR was 8.9% (95% CI 7.0-11.1) for packed red blood cells (pRBCs) and 4.5% (95% CI 2.9-6.6) for plasma products. The most frequently reported TRs were febrile nonhemolytic TRs (FNHTR; 4%, 95% CI 2.8-5.5) when administering pRBCs and allergic TRs (3.2%, 95% CI 1.80-5.10) when administering plasma products. A higher dose of pRBC (adjusted odds ratio [aOR] 1.04 [95% CI 1.00-1.08]) was associated with a higher odds of TR. Administration of pRBCs stored for longer than 28 days was associated with higher odds of FNHTR (aOR 4.10 [95% CI 1.58-10.65]) and acute hemolytic TR (AHTR; OR 15.2 [95% CI 3.35-68.70]) when compared with pRBCs stored for 14 days or fewer. Leukoreduction of pRBC was not associated with lower odds of developing a TR (OR 1.47 [95% CI 0.89-2.42]).CONCLUSIONS AND CLINICAL IMPORTANCE: Clinicians should be mindful of the age and dose of pRBC prescribed to dogs.</p

Realising the full potential of data-enabled trials in the UK : a call for action

Rationale: Clinical trials are the gold standard for testing interventions. COVID-19 has further raised their public profile, and emphasised the need to deliver better, faster, more efficient trials for patient benefit. Considerable overlap exists between data required for trials and data already collected routinely inelectronic healthcare records (EHR). Opportunities exist to utilise these in innovative ways to decrease duplication of effort, and speed trial recruitment, conduct and follow-up. Approach: The National Institute of Health Research (NIHR), Health Data Research UK (HDR UK) and Clinical Practice Research Datalink (CPRD) co-organised a national workshop to accelerate the agenda for “data-enabled clinical trials”. Showcasing successful examples and imagining future possibilities, the plenary talks, panel discussions, group discussions and case studies covered: design/feasibility; recruitment; conduct/follow-up; collecting benefits/harms; and analysis/interpretation. Reflection: Some notable studies have successfully accessed and used EHR to identify potential recruits, support randomised trials, deliver interventions and supplement/replace trial-specific follow-up. Some outcome measures are already reliably collected; others, like safety, need detailed work to meet regulatory reporting requirements. There is a clear need for system interoperability and a “route map” to identify and access the necessary datasets. Researchers running regulatory-facing trials must carefully consider how data quality and integrity would be assessed. An experience-sharing forum could stimulate wider adoption of EHR-based methods in trial design and execution. Discussion: EHR offer opportunities to better plan clinical trials, assess patients and capture data more efficiently, reducing research waste and increasing focus on each trial’s specific challenges. The short-term emphasis should be on facilitating patient recruitment and for post-marketing authorisation trials where research-relevant outcome measures are readily collectable. Sharing of case studies is encouraged. The workshop directly informed NIHR’s funding call. ambitious data-enabled trials at scale. There is the opportunity for the United Kingdom to build upon existing data science capabilities to identify, recruit and monitor patients in trials at scale