Machine Learning Algorithm to Predict Acidemia Using Electronic Fetal Monitoring Recording Parameters

Background: Electronic fetal monitoring (EFM) is the universal method for the surveillance of fetal well-being in intrapartum. Our objective was to predict acidemia from fetal heart signal features using machine learning algorithms. Methods: A case–control 1:2 study was carried out compromising 378 infants, born in the Miguel Servet University Hospital, Spain. Neonatal acidemia was defined as pH < 7.10. Using EFM recording logistic regression, random forest and neural networks models were built to predict acidemia. Validation of models was performed by means of discrimination, calibration, and clinical utility. Results: Best performance was attained using a random forest model built with 100 trees. The discrimination ability was good, with an area under the Receiver Operating Characteristic curve (AUC) of 0.865. The calibration showed a slight overestimation of acidemia occurrence for probabilities above 0.4. The clinical utility showed that for 33% cutoff point, missing 5% of acidotic cases, 46% of unnecessary cesarean sections could be prevented. Logistic regression and neural networks showed similar discrimination ability but with worse calibration and clinical utility. Conclusions: The combination of the variables extracted from EFM recording provided a predictive model of acidemia that showed good accuracy and provides a practical tool to prevent unnecessary cesarean sections.     

An Information Quantity in Pure State Models

When we consider an error model in a quantum computing system, we assume a parametric model where a prepared qubit belongs. Keeping this in mind, we focus on the evaluation of the amount of information we obtain when we know the system belongs to the model within the parameter range. Excluding classical fluctuations, uncertainty still remains in the system. We propose an information quantity called purely quantum information to evaluate this and give it an operational meaning. For the qubit case, it is relevant to the facility location problem on the unit sphere, which is well known in operations research. For general cases, we extend this to the facility location problem in complex projective spaces. Purely quantum information reflects the uncertainty of a quantum system and is related to the minimum entropy rather than the von Neumann entropy.     

Numerical and Experimental Investigation of the Conjugate Heat Transfer for a High-Pressure Pneumatic Control Valve Assembly

This paper uses heat transfer experiments and computational fluid dynamics (CFD) simulations to investigate the conjugate heat transfer (CHT) in a high-pressure pneumatic control valve assembly. A heat transfer test rig was constructed, and time–temperature histories of five test points placed on the valve assembly’s outer surface were recorded for study validation. The Unsteady Reynolds-Averaged Navier–Stokes (URANS) CFD methods with the standard k-ε turbulence closure equations were adopted in the numerical computations. Polyhedral grids were used; time step and mesh convergence studies were conducted. Simulated and measured temperatures profile comparisons revealed a good agreement. The CHT results obtained from CFD showed huge velocity fields downstream of the valve throat and the vent hole. The airflow through the valve was icy, mainly in the supersonic flow areas. Low temperatures below 273.15 K were recorded on the internal and external walls of the valve assembly. The consistency of the measured data with the numerical results demonstrates the effectiveness of polyhedral grids in exploring the CHT using CFD methods. The local entropy production rate analysis revealed that irreversibility is mainly due to viscous dissipation. The current CHT investigation provides a potential basis for thermostress analysis and optimization.     

基于Gabor和PCA的面部图像识别方法

文中利用Gabor变换和PCA降维的优点,提出了Gabor+PCA的面部图像识别方法.该方法先提取图像的Gabor特征,然后将Gabor特征与原图像特征结合构成新的融合特征并用PCA降维,最后用KNN分类器分类.所提Gabor+PCA方法不仅能挖掘出图像的细节信息,而且拓宽了特征空间的维数.另外,Gabor+PCA方法...     

Combined use of nuclear magnetic resonance and infrared spectroscopy for studying recognition processes between amphenicolic antibiotics and albumin

Biological reactions are mostly concerned with selective interactions between small ligands and macromolecular receptors. The same ligands may activate responses of different intensities and/or effects in the presence of different receptors. Many approaches based on spectroscopic and non‐spectroscopic methods have been used to study interactions between small ligands and macromolecular receptors, including methods based on NMR and IR spectroscopic analysis of the solution behaviour of the ligand in the presence of receptors. In this work, we investigated the interaction between ovine serum albumin with two amphenicolic antibiotics [chloramphenicol (CAP) and thiamphenicol (TAP)], using a combined approach based on NMR and IR methodologies, furnishing complementary information about the recognition process occurring within the two systems. The two ligands, despite their similar structures, showed different affinities towards albumin. NMR methodology is based on the comparison of selective ( ) and non‐selective ( ) spin–lattice relaxation rates of the ligands in the presence and absence of macromolecular receptors and and temperature dependence analysis. From these studies, the ligand–receptor binding strength was evaluated on the basis of the ‘affinity index.’ The derivation of the affinity index from chemical equilibrium kinetics for both the CAP–albumin and TAP–albumin systems allowed a comparison of the abilities of the two amphenicolic antibiotics to interact with the protein. IR methodology is based on the comparison of the ligand–protein ‘complex’ spectra with those of the non‐interacting systems. On the basis of the differences revealed, a more thorough IR analysis was performed in order to understand the structural changes which occurred on both ligand and protein molecules within the interacting system. Copyright © 2003 John Wiley & Sons, Ltd.     

沥青基球状活性炭气相吸脱附行为研究

本文利用热重法研究了一系列沥青基球状活性炭对蒸汽及正已烷蒸汽的动态吸脱附曲线。结果表明,PSAC对苯蒸汽的吸附及再生性能优良。随吸附温度的降低、比表面积的增大、总孔容及微孔容的增大,PSAC对苯蒸汽的吸附容量增大。PSAC对正已烷的吸附速度大于对苯蒸汽的吸附速度,但其对正已烷的平衡吸附容量小于对苯蒸汽的平衡吸附容量。     

骨断裂力学概述

本文涉及近年来骨断裂力学的发展成果.对建立在张开型和剪切型断裂能基础上的方法作了回顾,并讨论了密度、试件厚度和裂纹速度对骨断裂的影响.最后简述了人股骨的试验研究.      

烧结温度和升温速率对Pb(Sb1/3Mn2/3)0.05Zr0.47Ti0.48O3压电陶瓷性能的影响

采用传统固相法制备了Pb(Sb1/3 Mn2/3)0.05Zr0.47Ti0.48 O3 (PMS-PZT)压电陶瓷.利用XRD、SEM和EDS等研究PMS-PZT陶瓷体系在烧结过程中形成的过渡液相和形成过渡液相温度(1100℃)附近的升温速率对陶瓷结构、压电和介电性能的影响.结果表明:不同烧结温度下,所有样品均为单一的钙钛矿四方相,过渡液相不会对相的结构有影响,但是当烧结温度较低时,过渡液相在烧结后期以玻璃相在晶界附近富集,对陶瓷的压电和介电性能有很大影响.随着烧结温度和升温速率的升高,PMS-PZT晶粒尺寸增大,晶粒均匀性和规则性得以改善,晶化质量得到提高;d33测试和阻抗分析测试结果表明PMS-PZT样品在1100℃附近以7 ℃·min-1升温速率并在1250℃烧结时具有最好的压电和介电性能:d33 =313 C/N,kp=0.59,Qm=1481,εr=1437,tanδ=0.53;.     

Non-anticipative representations of Banach space valued gaussian processes with respect to brownian motion

Necessary and sufficient conditions are found for the equivalence of the measures associated with (i) a Banach space valued Gaussian process, with mean 0, and (ii) a Bach space valued Brownian motion. The notion of a non-anticipative representation of (i) with respect to (ii) is defined and in the case of equivalence of the measures it is shown that such a representation exists and has an explicit stochastic integral form which is invertible. Theorems of Ershov on absolute continuity of measures associated with diffusion processes are extended to Banach space. Applications to infinite-dimensional filtering are considered.     

The Influence of Visual and Spatial Reasoning in Interpreting Simulated 3D Worlds

This paper explores the way in which young children (6 year olds) made sense of screen-based images on the computer. The participants were required to interpret 3D-like representations and relate these images to objects in their environment. Both static and relatively dynamic software programs were used in the investigation. Some of the children could not make links between the screen representation and the intended three-dimensional (3D) objects. It is argued that young children should be exposed to activities that establish explicit links between 2D and 3D objects ``away' from the computer before attempting the more difficult links required to interpret and represent 3D objects in ICT contexts. This revised version was published online in July 2006 with corrections to the Cover Date.