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31.
OBJECTIVE: To identify characteristics associated with provision of bystander CPR in witnessed out-of-hospital cardiac arrest cases. METHODS: An observational, prospective, cohort study was performed using cardiac arrest cases as identified by emergency medical services (EMS) agencies in Oakland County. MI, from July 1, 1989, to December 31, 1993. All patients who sustained a witnessed arrest prior to arrival of EMS personnel were reviewed. RESULTS: Of the 927 patients meeting entry criteria, the 229 patients receiving bystander CPR were younger: 60.9 +/- 14.7 vs 67.9 +/- 14.7 years (p < 0.01). Most (76.6%) cardiac arrests occurred in the home. In a multivariate logistic model, only the location of arrest outside the home was a significant predictor of receiving bystander CPR [odds ratio (OR) 3.8; 99% CI 2.5, 5.9]. Arrests outside the home were associated with significantly improved outcome, with 18.2% of out-of-home and 8.2% of in-home victims discharged from the hospital alive (OR 2.5; 99% CI 1.4, 4.4). CONCLUSION: Patients who have had witnessed cardiac arrests outside the home are nearly 4 times more likely to receive bystander CPR, and are twice as likely to survive. This observation emphasizes the need for CPR training of family members in the authors' locale. This phenomenon may also represent a significant confounder in studies of out-of-hospital cardiac arrest and resuscitation. 相似文献
32.
The thermal stability of members of several series of polyitaconates has been assessed using thermogravimetric and thermal volatilisation techniques. From these data general degradation patterns have been established. The poly (di-n-alkyl itaconates) are stable up to 570K before chain breakdown occurs. The poly(mono-n-alkyl itaconates) are less stable and undergo a dehydration/de-esterification reaction at 430K which results in the formation of anhydride structures. This reaction can be suppressed by the formation of the salts. In the copolymers, salt formation also leads to increased stability but the range of copolymers studied was too restricted to draw general conclusions about their thermal behaviour. 相似文献
33.
An optimum water distribution system is designed using linear programming. The proposed algorithm, developed by applying an analogy of electrical network theory, discusses a distribution system with multiple supply points in comparison to an earlier paper by Gupta where the distribution system was restricted to only one source. The electrical network analogy is fully explained and a case example with two sources of supply is solved. 相似文献
34.
The mechanical behavior of semicrystalline isotactic polypropylene (iPP) of different crystallinity, crystal morphology and
superstructure was investigated by standard tensile stress–strain analysis, dynamic-mechanical analysis, and in situ observation
of the deformation by atomic force microscopy (AFM). Emphasis is put on the comparison of the mechanical characteristics of
specimens containing either non-isometric lamellae, being arranged in spherulites, or nodular isometric domains, which are
not organized in a superstructure. The formation of lamellae/spherulites and of nodules was controlled by the conditions of
crystallization. The replacement of cross-hatched monoclinic lamellae and a spherulitic superstructure by randomly arranged
isometric nodules leads to a distinct increase of the ductility and toughness, even if the crystallinity is identical. The
modulus of elasticity and the yield stress increase as expected with increasing crystallinity. Slightly lower values of Young’s
modulus and yield strength are detected if samples contained non-lamellar crystals in a non-spherulitic superstructure, proving
an effect of the crystal shape on the deformation behavior. For the first time, tensile deformation of semicrystalline iPP
which contains nodular ordered domains instead of lamellae has been followed by in situ AFM. 相似文献
35.
Eshan Ganju Monica Prezzi Rodrigo Salgado Nayyar Zia Siddiki 《International Journal of Pavement Engineering》2018,19(11):966-975
The Dynamic Cone Penetrometer (DCP) is a device that is used in the construction industry for the assessment of in situ soil compaction quality. Over the past few decades, numerous correlations have been developed between the DCP test results and soil strength and stiffness parameters. This paper proposes a comprehensive set of criteria and recommendations for quality control (QC) of compacted subgrade that take into account the inherent statistical variability of DCP test results. For the development of the QC criteria, a new statistical methodology is used to extract representative test values from the raw field DCP test data. In order to use the proposed QC criteria, soils are first classified into two broad categories (fine-grained and coarse-grained) depending on their fabric and response to compaction efforts. Test results indicate that (i) for fine-grained soils, the DCP test values have good correlation with the plasticity index (PI), which is indicative of the type and amount of clay content of the soil and (ii) for coarse-grained soils, the DCP test values have good correlation with the optimum water content of the soil, which is directly related to its in situ density. DCP blow count correlation equations are presented for both soil categories. Recommendations for field DCP testing and data analysis are also provided to highlight the significance of the statistical distribution of the DCP test results in QC testing of compacted subgrade. 相似文献
36.
37.
Omar Rabbani Munshoor Ahmed Saqib Zia 《Computers & Mathematics with Applications》2019,77(12):3195-3211
This paper focuses on implementation of space–time CE/SE scheme for computing the transport of a passive pollutant by a flow. The flow model comprises of the Saint-Venant system of shallow water equations and the pollutant propagation is described by a transport equation. The one-dimensional and two-dimensional flow equations are numerically investigated using the CE/SE scheme. A number of test problems are presented to check the accuracy and efficiency of the proposed scheme. The results of CE/SE scheme are compared with the central scheme. Both the schemes are found to be in close agreement. However, our proposed CE/SE scheme accurately captures shocks and discontinuous profiles. 相似文献
38.
Muhammad Zia ul Mustafa Hilmi bin Mukhtar Nik Abdul Hadi Md Nordin Hafiz Abdul Mannan Rizwan Nasir Nabilah Fazil 《化学工程与技术》2019,42(12):2580-2593
Flue gas emissions and the harmful effects of these gases urge to separate and capture these unwanted gases. Ionic liquids due to negligible vapor pressure, thermal stability, and wide electrochemical stability have expanded its application in gas separations. A comprehensive overview of the recent developments and applications of ionic liquid membranes (ILMs) for gas separation is given. The three general classifications of ILMs, such as supported ionic liquid membranes (SILMs), ionic liquid polymeric membranes (ILPMs), and ionic liquid mixed‐matrix membranes (ILMMMs) along with their applications, for the separation of various mixed gases systems is discussed in detail. Furthermore, issues, challenges, computational study, and future perspectives for ILMs are also considered. 相似文献
39.
Zia Ul-Haq Zertasha Ramzan Salman Tariq Syeda Adila Batool Muhammad Ali Javed Sami 《International journal of remote sensing》2018,39(2):544-564
This article presents a comparison analysis of OMIT (Ozone Monitoring Instrument retrieved overpass total ozone column (TOC)), and DOST (Dobson Ozone Spectrophotometer observed TOC) over Delhi during a period from October 2004 to June 2011. Megacity Delhi, located in Indo-Gangetic Basin, is an important site for comparison of ground-based and satellite retrieved TOCs due to significant anthropogenic emissions of ozone precursors, large shift in seasons, and large-scale crop residue burning in the region. DOST and OMIT data show an overall bias of 3.07% and significant correlation with coefficient of determination R2 = 0.73. Large seasonal fluctuations in the biases and correlations have been observed ranging from 2.46% (winter) to 3.82% (spring), and R2 = 0.84 (winter) to R2 = 0.09 (summer), respectively. The large biases are attributed to changes in temperature, cloud cover, pollutants emissions from urban area, and crop-residue burning events. We also find notable variations in correlations between the datasets due to the varying burden of absorbing aerosols from open field crop-residue burning. The R2 has changed from 0.67 (for aerosol optical depth, AOD 1.5–3.5) to 0.77 (for AOD 0–0.99). The dependence of the bias on solar zenith angle, cloud fraction, and satellite distance is also discussed. A simple linear regression analysis is applied to check the linkage between DOST and OMIT. The influence of atmospheric air temperature and relative humidity on OMIT at different pressure levels between 1000 and 20 hPa has been discussed. 相似文献
40.
A new rectangular window based image cropping method for generalization of brain neoplasm classification systems
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Razia Zia Pervez Akhtar Arshad Aziz 《International journal of imaging systems and technology》2018,28(3):153-162
Classification of brain neoplasm images is one of the most challenging research areas in the field of medical image processing. The main objective of this study is to design a brain neoplasm classification system that can be trained using multiple various sized MR images of different institutions. The proposed method is a generalized classification system; it can be used in a single institute or in a number of institutions at the same time, without any restriction on image size. The generalization and unbiased capability of the proposed method can bring researchers on a single platform to work on some standard forms of computer aided diagnosis system with more efficient diagnostic capabilities. In this study, a suitable size of moveable rectangular window is used between segmentation and feature extraction stages. A semiautomatic, localized region based active contour method is used for segmentation of brain neoplasm region. Discrete wavelet transform for feature extraction, principal component analysis for feature selection and support vector machine is used as classifier. For the first time MR images of 2 sizes and from different institutions are used in training and testing of brain neoplasm classifier. Three glioma grades were classified using 92 MR images. The proposed method achieved the highest accuracy of 88.26%, the highest sensitivity of 92.23% and the maximum specificity of 93.93%. In addition, the proposed method is computationally less complex, requires shorter processing time and is more efficient in terms of storage capacity. 相似文献