Interactive Spaced Online Education in Pediatric Trauma

Pediatric resident trauma education is suboptimal due to lack of a curriculum and limited trauma experience and education resources. The objective of the study was to test knowledge retention and acceptability of interactive spaced education (ISE) in pediatric trauma. Prospective, randomized trial involving 40 physicians in a pediatric emergency department was used. Instrument was comprised of 48 multiple-choice questions (evaluative component) and answer critiques (educational component) on pediatric trauma divided into two modules. The instrument was assessed for test–retest reliability, item difficulty, and construct validity. Intervention consisted of online administration of each module as eight spaced emails (3 questions each) over a course of 4 weeks and was repeated after 2 and 4 months. Participants received an answer critique on committing to an answer. Primary outcome was difference in mean percentage of correct answers at 2 and 4 months versus baseline. Paired t test and effect size (d) were performed. Secondary outcome was exit-survey of ISE acceptability. There was significant improvement at 2 months (8.0, 95% confidence intervel [CI] = [3.6, 12.5], d = 0.75), but improvement at 4 months (1.6, 95% CI = [−4.5, 7.7], d = 0.18) was not significant. Sixty percent would retake and recommend ISE to others. Interactive, spaced education improves knowledge in pediatric trauma and is well accepted. Studies are required to determine the optimal spacing interval for this form of education

An EM-like algorithm for the semiparametric accelerated failure time gamma frailty model

The frailty model is one of the most popular models used to analyze clustered failure time data, and the frailty term in the model is used to assess associations in each cluster. The frailty model based on the semiparametric accelerated failure time model attracts less attention than the one based on the proportional hazards model due to its computational difficulties. In this paper, we develop a new estimation method for the semiparametric accelerated failure time gamma frailty model based on the EM-like algorithm and the rank-like estimation method. The proposed method is compared with the existing EM algorithm, which incorporates the M-estimator in the M-step. From simulation studies, we show that the rank-like estimation method in the M-like step simplifies the estimation procedure and reduces the computational time by the linear programming approach. With respect to the accuracy of estimates and length of computational time, the proposed method outperforms the existing estimation methods. For illustration, we apply the proposed method to the data set of sublingual nitroglycerin and oral isosorbide dinitrate on angina pectoris of coronary heart disease patients.Accelerated failure time model Frailty EM-like algorithm Rank-like estimation

Multiple imputation method for the semiparametric accelerated failure time mixture cure model

There are few discussions on the semiparametric accelerated failure time mixture cure model due to its complexity in estimation. In this paper, we propose a multiple imputation method for the semiparametric accelerated failure time mixture cure model based on the rank estimation method and the profile likelihood method. Both approaches can be easily implemented in R environment. However, the computation time for the rank estimation method is longer than that from the profile likelihood method. Simulation studies demonstrate that the performances of estimated parameters from the proposed methods are comparable to those from the expectation maximization (EM) algorithm, and the estimated variances are comparable to those from the empirical approach. For illustration, we apply the proposed method to a data set of failure times from the bone marrow transplantation.Accelerated failure time model Mixture cure model Multiple imputation Rank estimation method Profile likelihood method

Wavefront Aberration Measurement Deflectometry for Imaging Lens Tests

Lenses play an important role in imaging systems. Having an effective way to test the aberrations of imaging lenses is important. However, the existing methods cannot satisfy the requirements in some conditions. To overcome these difficulties, wavefront aberration measurement deflectometry (WAMD) is proposed in this paper, which can reconstruct the wavefront aberrations of imaging lenses by measuring the angular aberrations. The principle of WAMD is analyzed in detail, and the correctness and feasibility of the proposed method are verified by both a simulation and an experiment. A telephoto lens and a single imaging lens were tested in an experiment, and the RMS errors were 166.8 nm (5.71%) and 58.9 nm (4.74%), respectively, as compared with the interferometer’s results. This method is widely applicable with relatively reasonable accuracy. It has potential to be applied in the lens manufacturing and alignment process

Coupling of material point and continuum discontinuum element methods for simulating blast-induced fractures in rock

A rock blasting simulation method is proposed that couples the material point method (MPM) and continuum discontinuum element method (CDEM). Blast-induced rock fractures are captured by the CDEM using normal and shear springs, and the explosive detonation is simulated by the MPM with a Jones-Wilkins-Lee equation of state. A particle-surface/edge contact method is introduced into the MPM-CDEM to calculate the interaction between the detonation products and rock medium. Three numerical examples are presented to verify the effectiveness of the proposed method. The fracture degree is represented as the ratio of the number of fractured springs to the total number of springs, and is used to analyze the evolution of shear and tension cracks under blasting. The simulation results show that the proposed numerical method well simulates blast-induced rock fractures and considers both progressive rock fracturing and the real explosive detonation. In particular, the expansion of the detonation gas, crushed zone around the blasthole, radial cracks, and effects of pre-existing stress on the blast-induced fractures are all successfully simulated

Synthesis and electrochemical performance of cubic Co-doped Li4Ti5O12 anode material for high-performance lithium-ion batteries

Co-doped Li4Ti5O12 (LCTO) anode material for lithium-ion battery was synthesized via a mechanic ball-milling activation and high temperature solid state reaction using CoCO3, TiO2 and Li2CO3 as raw material. The structure, morphology and electrochemical properties of LCTO sample are characterized by X-ray diffraction (XRD), scanning electronic morphology (SEM), galvanostatic charge-discharge tests, cyclic voltammetry (CV) and electron chemical impedance spectroscopy (EIS) measurements. The LCTO is well crystallized as a spinet structure without any detectable impurity phase with the doping of Co. Thus, LCTO exhibits improving cycling stability and rate capability as anode material for lithium ion batteries, which delivered the initial specific capacity of 250, 222, 188, 180, 149 and 118 mAh g(-1), at 0.1, 0.2,1.0, 2.0, 5.0 and 10.0 degrees C rate in the voltage range of 0.5-3.0 V respectively, and discharge capacity of 200 mAh g(-1) after 100 cycles at 0.1 degrees C. EIS results further show that the main reason for the improved electrochemical performance of LCTO is its reduced electrochemical impedance, which mainly due to the Co-doped modification leads to O vacancies then results in increase amount of embedded lithium in LCTO materials. (C) 2016 Elsevier B.V. All rights reserved

Analysis and Optimization of a Compressed Air Energy Storage—Combined Cycle System

Compressed air energy storage (CAES) is a commercial, utility-scale technology that provides long-duration energy storage with fast ramp rates and good part-load operation. It is a promising storage technology for balancing the large-scale penetration of renewable energies, such as wind and solar power, into electric grids. This study proposes a CAES-CC system, which is based on a conventional CAES combined with a steam turbine cycle by waste heat boiler. Simulation and thermodynamic analysis are carried out on the proposed CAES-CC system. The electricity and heating rates of the proposed CAES-CC system are lower than those of the conventional CAES by 0.127 kWh/kWh and 0.338 kWh/kWh, respectively, because the CAES-CC system recycles high-temperature turbine-exhausting air. The overall efficiency of the CAES-CC system is improved by approximately 10% compared with that of the conventional CAES. In the CAES-CC system, compressing intercooler heat can keep the steam turbine on hot standby, thus improving the flexibility of CAES-CC. This study brought about a new method for improving the efficiency of CAES and provided new thoughts for integrating CAES with other electricity-generating modes