102 research outputs found
A Tale of Two Quantum Compass Models
We investigate two variants of quantum compass models (QCMs). The first, an
orbital-only honeycomb QCM, is shown to exhibit a quantum phase transition
(QPT) from a - to -ordered phase in the -Ising universality class,
in accord with earlier studies. In a fractionalized parton construction, this
describes a "superfluid-Mott insulator" transition between a higher-order
topological superfluid (HOTS) and the Toric code, the latter described as a
-wave resonating valence bond (RVB) state of the partons. The second
variant, the spinless fermion QCM on a square lattice, is of interest in
context of cold-atom lattices with higher-angular momentum states on each atom.
We explore finite-temperature orbital order-disorder transitions in the
itinerant and localized limits using complementary methods. In the itinerant
limit, we uncover an intricate temperature()-dependent dimensional crossover
from a high- "insulator"-like state, via an incoherent bad-metal-like state
at intermediate , to a two-dimensional insulator at low , well below the
"orbital" ordering scale. Finally, we discuss how engineering specific, tunable
and realistic perturbations in both these variants can act as a playground for
simulating a variety of exotic QPTs between topologically ordered and trivial
phases. In the cold-atom context, we propose a novel way to engineer a quantum
Lifshitz criticality at a QPT between a boson and a Bose-exciton superfluid. We
argue that advances in design of Josephson junction arrays and manipulating
cold-atom lattices offer the hope of simulating such novel phases of matter in
the foreseeable future.Comment: 16 pages, 12 figure
Enhanced Tensile properties of Stone wool fiber-reinforced high density polyethylene (HDPE) Composites
In this study, a minerl fiber composite of stone wool reinforced high density polyethylene (HDPE) with different weight percentage was tested. For preparation of the samples a hot pressing technique was used. Significant improvement of the tensile strength was observed for composites of stone wool HDPE with a fiber content of 20wt %. The fracture surface of the samples were analyzed for their inter layer bounding by SEM
Applications of graphene nanomaterials in energy storage—A state-of-art short review
The study presents the usage behavior of graphene in the energy field. Graphene has been comprehensively studied in the energy-related application due to higher conductivity and mechanical flexibility. The architecture of graphene permits it to strengthen and facilitate its application in the energy arena. Herein, the application of graphene in various energy storages such as fuel cells, dye-sensitized solar cells, batteries, nuclear power plants, and thermoelectric has been studied neatly. Graphene reacts towards these substances chemically, mechanically, and electrically to a great extend and appears with the excellent output of these objects. In the future graphene could be applied to the others field of energy and science successfully
Improved patient safety with a simplified operating room to pediatric intensive care unit handover tool (PATHQS)
IntroductionPatient handover is a crucial transition requiring a high level of coordination and communication. In the BC Children's Hospital (BCCH) pediatric intensive care unit (PICU), 10 adverse events stemming from issues that should have been addressed at the operating room (OR) to PICU handover were reported into the patient safety learning system (PSLS) within 1 year. We aimed to undertake a quality improvement project to increase adherence to a standardized OR to PICU handover process to 100% within a 6-month time frame. In doing so, the secondary aim was to reduce adverse events by 50% within the same 6-month period.MethodsThe model for improvement and a Plan, Do, Study, Act method of quality improvement was used in this project. The adverse events were reviewed to identify root causes. The findings were reviewed by a multidisciplinary inter-departmental group comprised of members from surgery, anesthesia, and intensive care. Issues were batched into themes to address the most problematic parts of handover that were contributing to risk.InterventionA bedside education campaign was initiated to familiarize the team with an existing handover standard. The project team then formulated a new simplified visual handover tool with the mnemonic “PATHQS” where each letter denoted a step addressing a theme that had been noted in the pre-intervention work as contributing to adverse events.ResultsAdherence to standardized handover at 6 months improved from 69% to 92%. This improvement was sustained at 12 months and 3 years after the introduction of PATHQS. In addition, there were zero PSLS events relating to handover at 6 and 12 months, with only one filed by 36 months. Notably, staff self-reporting of safety concerns during handover reduced from 69% to 13% at 6 months and 0% at 3 years. The PATHQS tool created in this work also spread to six other units within the hospital as well as to one adult teaching hospital.ConclusionA simplified handover tool built collaboratively between departments can improve the quality and adherence of OR to PICU handover and improve patient safety. Simplification makes it adaptable and applicable in many different healthcare settings
Influences of Draw Forming Process on the Crash Analysis of a Circular Cup
The change of a structural part that occurred after forming process can affect crash response. Current industrial practice only utilizes the geometry in crash analysis. This study investigates the effect of forming histories of a circular cup formed by draw forming process in the crash simulation. Crash analysis at an initial velocity of 50km/h was performed using the explicit finite element code Radioss. The Johnson-Cook constitutive material model was used to characterize the material properties of advanced high strength steel DP600. Crash simulations are conducted in two different cases using a geometrical cup model with case 1 no forming history and case 2 all forming histories obtained from forming process. Results from this study indicate that the mechanical response of steel DP600 in a crash differ by 80.7 % for contact force and 5.87% for energy absorption when forming effects were considered. The contact force tends to increase more with displacement in case 2 compared to case 1. The non-uniform thickness and work hardening from forming process do alter significantly the crashworthiness of a structural part in the subsequent crash event
Auxin pretreatment promotes regeneration of sugarcane (Saccharum spp. hybrids) midrib segment explants
We have developed a new, simple,
quick and genotype-independent method for direct
regeneration of sugarcane using novel midrib
segment explants. Our protocol involves two
steps: the pretreatment of starting material on MS
(Murashige and Skoog (1962) Physiol Plant
15:473–497) medium containing 3.0 mg/l 2,4-
dichlorophenoxyacetic acid (2,4-D) for 8 days
under continuous dark and subsequent transfer of
the explants to MS medium augmented with
0.1 mg/l benzyladenine (BA) and 0.1 mg/l naphthaleneacetic
acid (NAA) under light-dark conditions.
On the regeneration medium, numerous
globular structures appeared from the explants
and subsequently differentiated into shoots.
Regenerated shoots attained 2–5 cm height
within 30 days of culture initiation and readily
rooted on MS basal medium. Hardened plants
were successfully established in the greenhouse.
The regulation of sugarcane morphogenesis by
auxin pretreatment is discussed
Queer In AI: A Case Study in Community-Led Participatory AI
Queerness and queer people face an uncertain future in the face of ever more widely deployed and invasive artificial intelligence (AI). These technologies have caused numerous harms to queer people, including privacy violations, censoring and downranking queer content, exposing queer people and spaces to harassment by making them hypervisible, deadnaming and outing queer people. More broadly, they have violated core tenets of queerness by classifying and controlling queer identities. In response to this, the queer community in AI has organized Queer in AI, a global, decentralized, volunteer-run grassroots organization that employs intersectional and community-led participatory design to build an inclusive and equitable AI future. In this paper, we present Queer in AI as a case study for community-led participatory design in AI. We examine how participatory design and intersectional tenets started and shaped this community’s programs over the years. We discuss different challenges that emerged in the process, look at ways this organization has fallen short of operationalizing participatory and intersectional principles, and then assess the organization’s impact. Queer in AI provides important lessons and insights for practitioners and theorists of participatory methods broadly through its rejection of hierarchy in favor of decentralization, success at building aid and programs by and for the queer community, and effort to change actors and institutions outside of the queer community. Finally, we theorize how communities like Queer in AI contribute to the participatory design in AI more broadly by fostering cultures of participation in AI, welcoming and empowering marginalized participants, critiquing poor or exploitative participatory practices, and bringing participation to institutions outside of individual research projects. Queer in AI’s work serves as a case study of grassroots activism and participatory methods within AI, demonstrating the potential of community-led participatory methods and intersectional praxis, while also providing challenges, case studies, and nuanced insights to researchers developing and using participatory methods
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Learning curves of basic laparoscopic psychomotor skills in SINERGIA VR simulator
Purpose: Surgical simulators are currently essential within any laparoscopic training program because they provide a low-stakes, reproducible and reliable environment to acquire basic skills. The purpose of this study is to determine the training learning curve based on different metrics corresponding to five tasks included in SINERGIA laparoscopic virtual reality simulator.
Methods: Thirty medical students without surgical experience participated in the study. Five tasks of SINERGIA were included: Coordination, Navigation, Navigation and touch, Accurate grasping and Coordinated pulling. Each participant was trained in SINERGIA. This training consisted of eight sessions (R1–R8) of the five mentioned tasks and was carried out in two consecutive days with four sessions per day. A statistical analysis was made, and the results of R1, R4 and R8 were pair-wise compared with Wilcoxon signed-rank test. Significance is considered at P value <0.005.
Results: In total, 84.38% of the metrics provided by SINERGIA and included in this study show significant differences when comparing R1 and R8. Metrics are mostly improved in the first session of training (75.00% when R1 and R4 are compared vs. 37.50% when R4 and R8 are compared). In tasks Coordination and Navigation and touch, all metrics are improved. On the other hand, Navigation just improves 60% of the analyzed metrics. Most learning curves show an improvement with better results in the fulfillment of the different tasks.
Conclusions: Learning curves of metrics that assess the basic psychomotor laparoscopic skills acquired in SINERGIA virtual reality simulator show a faster learning rate during the first part of the training. Nevertheless, eight repetitions of the tasks are not enough to acquire all psychomotor skills that can be trained in SINERGIA. Therefore, and based on these results together with previous works, SINERGIA could be used as training tool with a properly designed training program
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