666 research outputs found

    The Relationships among Chinese Practicing Teachers ’ Epistemic Beliefs, Pedagogical Beliefs and Their Beliefs about the Use of ICT

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    This study aimed to investigate the relationships among practicing teachers ’ epistemic beliefs, pedagogical beliefs and their beliefs about the use of ICT through survey methodology. Participants were 396 high school practicing teachers from mainland China. The path analysis results analyzed via structural equation modelling technique indicated that the systemic relationships among these three types of beliefs were nested. Specifically, teachers ’ sophisticated beliefs about the source of knowledge were aligned with constructivist pedagogical beliefs and constructivist use of ICT, with one belief highly related to another

    Deep Learning for Spin-Orbit Torque Characterizations with a Projected Vector Field Magnet

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    Spin-orbit torque characterizations on magnetic heterostructures with perpendicular anisotropy are demonstrated on a projected vector field magnet via hysteresis loop shift measurement and harmonic Hall measurement with planar Hall correction. Accurate magnetic field calibration of the vector magnet is realized with the help of deep learning models, which are able to capture the nonlinear behavior between the generated magnetic field and the currents applied to the magnet. The trained models can successfully predict the applied current combinations under the circumstances of magnetic field scans, angle scans, and hysteresis loop shift measurements. The validity of the models is further verified, complemented by the comparison of the spin-orbit torque characterization results obtained from the deep-learning-trained vector magnet system with those obtained from a conventional setup comprised of two separated electromagnets. The damping-like spin-orbit torque (DL-SOT) efficiencies (|ξDL\xi_{DL}|) extracted from the vector magnet and the traditional measurement configuration are consistent, where |ξDL\xi_{DL}| ≈\approx 0.22 for amorphous W and |ξDL\xi_{DL}| ≈\approx 0.02 for α\alpha-W. Our work provides an advanced method to meticulously control a vector magnet and to conveniently perform various spin-orbit torque characterizations

    Tracking and Following Algorithms of Mobile Robots for Service Activities in Dynamic Environments

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    By providing the capability of following a human target in an appropriate manner, the robot can assist people in various ways under different environments. One of the main difficulties when performing human tracking and following is the occlusion problem caused by static as well as dynamic obstacles. The aim of the paper is to tackle the occlusion problem by planning a robotic trajectory of maximizing target visibility and following the moving target. Initially, a laser range finder is used to detect the human target and then robustly track the target using the Kalman filter. Afterward, a human following algorithm based on a look-ahead algorithm, DWA*, is implemented to pursue the target while avoiding any static or dynamic obstacles. Fundamental experiments have been extensively tested to evaluate robot maneuvers and several field tests are conducted in more complex environments such as student cafeteria, computer center, and university library.</span

    Donorâ Acceptorâ Acceptor’s Molecules for Vacuumâ Deposited Organic Photovoltaics with Efficiency Exceeding 9%

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    Three vacuumâ deposited donorâ acceptorâ acceptor (dâ aâ a’) small molecule donors are studied with different side chains attached to an asymmetric heterotetracene donor block for use in high efficiency organic photovoltaics (OPVs). The donor with an isobutyl side chain yields the highest crystal packing density compared to molecules with 2â ethylhexyl or nâ butyl chains, leading to the largest absorption coefficient and short circuit current in an OPV. It also exhibits a higher fill factor, consistent with its preferred outâ ofâ plane molecular Ï â Ï stacking arrangement that facilitates charge transport in the direction perpendicular to the substrate. A power conversion efficiency of 9.3 ± 0.5% is achieved under 1 sun intensity, AM 1.5 G simulated solar illumination, which is significantly higher than 7.5 ± 0.4% of the other two molecules. These results indicate that side chain modification of dâ aâ a’ small molecules offers an effective approach to control the crystal packing configuration, thereby improving the device performance.Three vacuumâ deposited donorâ acceptorâ acceptor’s small molecule donors with different alkyl chain configurations (R1â R3) are synthesized and characterized to understand the side chain effect on organic photovoltaic (OPV) performance. The donor with an isobutyl (R3) chain yields the highest crystal packing density and largest short circuit current among the three molecules. Its preferred faceâ on molecular stacking orientation on the substrate leads to the highest fill factor. The optimized OPV structure achieves a power conversion efficiency (PCE) = 9.3 ± 0.5%.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/1/aenm201703603.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/2/aenm201703603-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/3/aenm201703603_am.pd

    Effectiveness of mechanical chest compression for out-of-hospital cardiac arrest patients in an emergency department

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    AbstractBackgroundTo increase the chance of restoring spontaneous circulation, cardiopulmonary resuscitation (CPR) with high-quality chest compressions is needed. We hypothesized that, in a municipal hospital emergency department, the outcome in nontraumatic out-of-hospital cardiac arrest patients treated with standard CPR followed by mechanical chest compression (MeCC) was not inferior to that followed by manual chest compression (MaCC). The purposes of the study were to test our hypothesis and investigate whether the use of MeCC decreased human power demands for CPR.MethodsA total of 455 consecutive out-of-hospital cardiac arrest patients of presumed cardiac etiology were divided into two groups according to the chest compressions they received (MaCC or MeCC) in this retrospective review study. Human power demand for CPR was described according to the Basic Life Support/Advanced Cardiovascular Life Support guidelines and the device handbook. The primary endpoint was recovery of spontaneous circulation during resuscitation, and the secondary endpoints were survival to hospital admission and medical human power demands.ResultsIn this study, recovery of spontaneous circulation was achieved in 33.3% of patients in the MeCC group and in 27.1% in the MaCC group (p = 0.154), and the percentages of patients who survived hospitalization were 22.2% and 17.6%, respectively (p = 0.229). A ratio of 2:4 for the human power demand for CPR between the groups was found. Independent predictors of survival to hospitalization were ventricular fibrillation/pulseless ventricular tachycardia as initial rhythm and recovery of spontaneous circulation.ConclusionNo difference was found in early survival between standard CPR performed with MeCC and that performed with MaCC. However, the use of the MeCC device appears to promote staff availability without waiving patient care in the human power-demanding emergency departments of Taiwan hospitals

    Open lung biopsy in early-stage acute respiratory distress syndrome

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    INTRODUCTION: Acute respiratory distress syndrome (ARDS) has heterogeneous etiologies, rapid progressive change and a high mortality rate. To improve the outcome of ARDS, accurate diagnosis is essential to the application of effective early treatment. The present study investigated the clinical effects and safety of open lung biopsy (OLB) in patients with early-stage ARDS of suspected non-infectious origin. METHODS: We undertook a retrospective study of 41 patients with early-stage ARDS (defined as one week or less after intubation) who underwent OLB in two medical intensive care units of a tertiary care hospital from 1999 to 2005. Data analyzed included baseline characteristics, complication rate, pathological diagnoses, treatment alterations, and hospital survival. RESULTS: The age of patients was 55 Âą 17 years (mean Âą SD). The average ratio of arterial partial pressure of oxygen (PaO(2)) to fraction of inspired oxygen (FiO(2)) was 116 Âą 43 mmHg (mean Âą SD) at biopsy. Seventeen patients (41%) were immunocompromised. Postoperative complications occurred in 20% of patients (8/41). All biopsies provided a pathological diagnosis with a diagnostic yield of 100%. Specific pathological diagnoses were made for 44% of patients (18/41). Biopsy findings led to an alteration of treatment modality in 73% of patients (30/41). The treatment alteration rate was higher in patients with nonspecific diagnoses than in patients with specific diagnoses (p = 0.0024). Overall mortality was 50% (21/41) and was not influenced by age, gender, pre-OLB oxygenation, complication rate, pathological results, and alteration of treatment. There was no surgery-related mortality. The survival rate for immunocompromised patients was better than that for immunocompetent patients (71% versus 33%; p = 0.0187) in this study. CONCLUSION: Our retrospective study suggests that OLB was a useful and acceptably safe diagnostic procedure in some selected patients with early-stage ARDS

    Fabrication of blue top-emitting organic light-emitting devices with highly saturated color

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    Abstract Blue top-emitting organic light-emitting devices (TOLEDs) with highly saturated color were developed by microcavity effect. The device structure studied was glass/reflective silver/indium-tin oxide (ITO)/organic electroluminescent stack/semi-transparent cathode (calcium/silver). By changing the thicknesses of ITO and organic layers in the microcavity structure device doped with p-bis(p-N, Ndi-phenyl-aminostyryl)benzene (DSA-ph), highly saturated color with Commission Internationale de L&apos;Eclairage chromaticity coordinates (CIE x;y ) of (0.14, 0.08) was obtained

    Mortality risk factors in patients with Acinetobacter baumannii ventilator-associated pneumonia

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    Background/PurposeVentilator-associated pneumonia (VAP) caused by Acinetobacter baumannii has contributed to high mortality rate, prolonged stays in the intensive care unit, and the rapid development of antimicrobial resistance to commonly used antimicrobials. This study sought to determine predictors of mortality and carbapenem resistance for patients with A baumannii VAP.MethodsWe retrospectively reviewed 541 adult patients with A baumannii pneumonia, who were admitted to a medical center between 2005 and 2007; of which 180 (33.3%) had been treated with mechanical ventilation. Of the 180 patients, 98 (54.4%) who survived were categorized as the survivor group, and 82 (45.6%) who died as the mortality group. Eighty-seven (48.3%) with imipenem-sensitive A baumannii VAP were categorized as the IS-AB group, and the remaining 93 (51.7%) with imipenem-resistant VAP as the IR-AB group.ResultsCompared with the survivor group, the mortality group had significantly higher Charlson comorbidity index scores, and more neoplastic disease, other sites of infection, bloodstream infections, altered mental status, confusion, urea >7 mmol/L, respiratory rate >30/min, low blood pressure (systolic <90 mmHg or diastolic <60 mmHg), age >65 years (CURB-65) ≥ 3, creatinine > 1.6 mg/dL, C-reactive protein ≥ 100 mg/L, and imipenem resistance. The survivor group had more cases of tracheostomy and diabetes mellitus than the mortality group had. Compared with the IS-AB group, the IR-AB group had higher Charlson comorbidity index scores, longer stays before VAP onset, an increase in other sites of infection, white blood cell count <4/μL or >1.1 × 104/μL, and higher hospital mortality rates.ConclusionInadequate initial empiric antimicrobial therapy and higher disease severity scores, including CURB ≥ 3 and C-reactive protein ≥ 120 mg/L, were independent risk factors associated with higher mortality rates for A baumannii pneumonia. Length of stay before VAP and white blood cell count <4/μL or >1.1 × 104/μL were independent risk factors for carbapenem resistance

    Urinary Macrophage Migration Inhibitory Factor Serves as a Potential Biomarker for Acute Kidney Injury in Patients with Acute Pyelonephritis

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    Conventional markers of kidney function that are familiar to clinicians, including the serum creatinine and blood urea nitrogen levels, are unable to reveal genuine injury to the kidney, and their use may delay treatment. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine, and the predictive role and pathogenic mechanism of MIF deregulation during kidney infections involving acute kidney injury (AKI) are not currently known. In this study, we showed that elevated urinary MIF levels accompanied the development of AKI during kidney infection in patients with acute pyelonephritis (APN). In addition to the MIF level, the urinary levels of interleukin (IL)-1β and kidney injury molecule (KIM)-1 were also upregulated and were positively correlated with the levels of urinary MIF. An elevated urinary MIF level, along with elevated IL-1β and KIM-1 levels, is speculated to be a potential biomarker for the presence of AKI in APN patients
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