244 research outputs found
Shaped sensor for material agnostic Lamb waves direction of arrival (DoA) estimation
No full textIn this work, a sensor formed by clustering three ad-hoc shaped piezoelectric patches is proposed for guided waves direction of arrival (DoA) estimation in laminate composite and metallic structures. The irregular shaping of the transducer electrodes allows to simplify the signal processing procedures which are necessary to detect the wave DoA. The cluster is conceived so that there is a linear dependence between the difference in time of arrival (DToA) of the wavefront at two of the sensor patches and the DoA of the wavefront itself. The third piezoelectric patch is shaped so that the estimation of the DoA from the DToA can be performed without knowing the actual wave velocity. The transducer performance in terms of DoA estimation accuracy are evaluated through numerical simulations, in which the plate response to a point source is evaluated in the frequency domain using the Green's function approach. Results show that the standard deviation of the error in the estimation of the DoA is less than 2°. This device is meant as a basic building block for the development of passive sensor networks in smart structure applications
POSSIBLE EVIDENCE OF QUANTUM-SIZE EFFECTS IN X-RAY PHOTOEMISSION SPECTRA OF ULTRATHIN SI LAYERS
No full textThis letter reports the experimental evidence of a 2.3 eV blue shift of the plasmon loss lines observed in the x-ray photoelectron spectra of an ultrathin Si layer equivalent to 1.5 X 10(15) at./cm(2) deposited onto a randomly oriented Al2O3 Single crystal. The plasmon line shifts, which is roughly proportional to the deposited Si(mass)(-2/3), are attributed to quantum confinement effects in agreement with electron energy loss measurements performed on nanosized Si particles
The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa
No full textTotal body water (TBW) was measured by deuterium oxide (D2O) dilution and predicted from bioelectrical impedance (Z) in nineteen anorexic and twenty-seven control women. The equation of Kushner et al, (1992) based on the impedance index (ZI = height(2)/Z) gave biases of 0.9 (SD 2.5) and 0.8 (SD 2.5) litres in controls and patients respectively (NS, ANOVA). The ZI-based equation of Deurenberg et al, (1993) gave biases of 1.5 (SD 2.4) litres (NS) and 3.0 (SD 2.1) litres (P < 0.001) in controls and patients respectively. Despite the fact that weight was the most powerful predictor of TBW on the study sample (n 46, r(2) 0.90, P < 0.0001, SE of the estimate 1.6 litres, CV 5.7 %), the formulas of Segal et al. (1991) and Kushner et al, (1992) based on the association of weight and ZI gave an inaccurate prediction of TBW in both control and anorexic subjects, with a bias ranging from -3.2 (SD 2.4) to 2.9 (SD 2.1) litres (P less than or equal to 0001). Population-specific formulas based on ZI (n 46) gave a more accurate prediction of TBW by bioelectrical impedance analysis on the study subjects, with biases of -0.1 (SD 1.8) and 0.5 (SD 1.7) litres in controls and patients respectively (NS). However, the individual bias was sometimes high. It is concluded that bioelectrical impedance analysis can be used to predict TBW in anorexic women at a population level, but the predictions are less good than those based on body weight alone
The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa
No full textTotal body water (TBW) was measured by deuterium oxide (D2O) dilution and predicted from bioelectrical impedance (Z) in nineteen anorexic and twenty-seven control women. The equation of Kushner et al, (1992) based on the impedance index (ZI = height(2)/Z) gave biases of 0.9 (SD 2.5) and 0.8 (SD 2.5) litres in controls and patients respectively (NS, ANOVA). The ZI-based equation of Deurenberg et al, (1993) gave biases of 1.5 (SD 2.4) litres (NS) and 3.0 (SD 2.1) litres (P < 0.001) in controls and patients respectively. Despite the fact that weight was the most powerful predictor of TBW on the study sample (n 46, r(2) 0.90, P < 0.0001, SE of the estimate 1.6 litres, CV 5.7 %), the formulas of Segal et al. (1991) and Kushner et al, (1992) based on the association of weight and ZI gave an inaccurate prediction of TBW in both control and anorexic subjects, with a bias ranging from -3.2 (SD 2.4) to 2.9 (SD 2.1) litres (P less than or equal to 0001). Population-specific formulas based on ZI (n 46) gave a more accurate prediction of TBW by bioelectrical impedance analysis on the study subjects, with biases of -0.1 (SD 1.8) and 0.5 (SD 1.7) litres in controls and patients respectively (NS). However, the individual bias was sometimes high. It is concluded that bioelectrical impedance analysis can be used to predict TBW in anorexic women at a population level, but the predictions are less good than those based on body weight alone
Feasibility, safety, and efficacy of a novel external compression vascular closure device: The LockeT® study
No full textDynamic data-driven management of atrial fibrillation with implantable cardiac monitors: The MONITOR AF study
No full textFormative Assessment Professional Development: Impact on Teacher Practice
No full textWith increasing demands on student achievement as set forth by the No Child Left Behind Act (NCLB) (2001), teachers are the catalyst for improving their students\u27 performance (Marzano, 2000). Existing studies on the use of formative assessment as a process by which teachers elicit information of their students\u27 progress and use that information to inform their instruction have shown promising results in student achievement gains (Wiliam & Thompson, 2007). Extensive teacher professional development is needed, however, to instill a change in teacher practice needed to successfully employ formative assessment resulting in improved student achievement (Trumbull & Lash, 2013; Wiley & Heritage, 2010). The purpose of this study was to determine the relationship between Linking Learning and Assessment professional development (including online training modules and communities of practice) as well as other forms of professional development on formative assessment and resulting self-perceived teacher practice, and what aspects of the professional development teachers found meaningful in improving their practice. This study utilized a mixed-methods design. A questionnaire was administered to middle level educators (N=82) throughout the state followed by a focus group interview (N=5). Quantitative data analysis consisted of descriptive statistics, correlations, Anova, and t-tests. Qualitative data were obtained through open-ended questions and the focus group. Content analysis was conducted to analyze the qualitative data obtained through the focus group interview and the open-ended questions on the questionnaire. A major finding of this study is that most teachers are in the early stages of implementing the formative assessment process and have begun to realize the power of formative assessment. Those who have had ongoing and intensive training have begun to see meaningful changes in their practice. Professional development found to be most meaningful to teachers includes: collaboration, active learning opportunities and coherence. In addition, teachers expressed the need for professional development to be differentiated to meet their individual needs. The results of this study may serve to inform teachers, administrators, districts and state departments of education when developing and implementing professional development in general as well as professional development on formative assessment
Adherence to guidelines for atrial fibrillation management of patients referred to cardiology departments: Studio Italiano multicentrico sul Trattamento della Fibrillazione Atriale (SITAF).
No full textAims
The purpose of this study was to evaluate adherence to national guidelines on the non-pharmacologic (ablative) treatment
of atrial fibrillation (AF).
Methods and results
This prospective, observational, transversal study enrolled 1256 consecutive in- and outpatients referred to 43 cardiology
departments between 1 and 31 October 2008 for the management of AF as a primary diagnosis. A rhythmcontrol
strategy (cardioversion, antiarrhythmic medication, pace-maker implantation, substrate ablation, alone or in combination) was prescribed in 865 (69%) of the patients and a rate-control strategy [drugs, atrioventricular junction ablation and pace-maker implantation (Ablate and Pace)] in 285 (23%). Specifically, substrate catheter ablation was indicated by the attending cardiologist in 187 (14.9%) patients and Ablate and Pace in 29 (2.3%). According to guideline indications, substrate catheter ablation would have been indicated in 183 (14.6%) patients, but only 105 (57%) of these were correctly identified by the attending cardiologist (K statistics for agreement for indications 0.49). Atrioventricular junction ablation and pace-maker implantation would have been indicated in 108 (8.6%) patients, but only
29 (27%) of these were correctly identified by the attending cardiologist (K statistics for agreement for indications
0.06).
Conclusion
About a quarter of patients referred to cardiology departments for AF management have potential indications for non-pharmacological treatment according to the guidelines. Substrate catheter ablation was offered by the attending cardiologist in a percentage similar to that expected, but concordance with guideline indications was moderate. Atrioventricular junction ablation and pace-maker implantation was largely underused.Aims The purpose of this study was to evaluate adherence to national guidelines on the non-pharmacologic (ablative) treatment of atrial fibrillation (AF). Methods and results This prospective, observational, transversal study enrolled 1256 consecutive in-and outpatients referred to 43 cardiology departments between 1 and 31 October 2008 for the management of AF as a primary diagnosis. A rhythm-control strategy (cardioversion, antiarrhythmic medication, pace-maker implantation, substrate ablation, alone or in combination) was prescribed in 865 (69) of the patients and a rate-control strategy [drugs, atrioventricular junction ablation and pace-maker implantation (Ablate and Pace)] in 285 (23). Specifically, substrate catheter ablation was indicated by the attending cardiologist in 187 (14.9) patients and Ablate and Pace in 29 (2.3). According to guideline indications, substrate catheter ablation would have been indicated in 183 (14.6) patients, but only 105 (57) of these were correctly identified by the attending cardiologist (K statistics for agreement for indications 0.49). Atrioventricular junction ablation and pace-maker implantation would have been indicated in 108 (8.6) patients, but only 29 (27) of these were correctly identified by the attending cardiologist (K statistics for agreement for indications 0.06). Conclusion About a quarter of patients referred to cardiology departments for AF management have potential indications for non-pharmacological treatment according to the guidelines. Substrate catheter ablation was offered by the attending cardiologist in a percentage similar to that expected, but concordance with guideline indications was moderate. Atrioventricular junction ablation and pace-maker implantation was largely underused. Published on behalf of the European Society of Cardiology. © The Author 2010
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