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Used Parameters (used + parameter)
Selected AbstractsVisual Quantitative Estimation: Semiquantitative Wall Motion Scoring and Determination of Ejection FractionECHOCARDIOGRAPHY, Issue 5 2003M.D., Steven J. Lavine Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two-dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid-ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder-cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG(r = 0.969), which was significantly greater than visual estimation(r = 0.896, P < 0.01). The limits of agreement for VQE (+12% to ,7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to ,11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF(r = 0.967, P < 0.001). We conclude that VQE provides highly correlated estimates of EF with RVG. (ECHOCARDIOGRAPHY, Volume 20, July 2003) [source] Integration of mobility and intrusion detection for wireless ad hoc networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2007Bo Sun Abstract One of the main challenges in building intrusion detection systems (IDSs) for mobile ad hoc networks (MANETs) is to integrate mobility impacts and to adjust the behaviour of IDSs correspondingly. In this paper, we first introduce two different approaches, a Markov chain-based approach and a Hotelling's T2 test based approach, to construct local IDSs for MANETs. We then demonstrate that nodes' moving speed, a commonly used parameter in tuning IDS performances, is not an effective metric to tune IDS performances under different mobility models. To solve this problem, we further propose an adaptive scheme, in which suitable normal profiles and corresponding proper thresholds can be selected adaptively by each local IDS through periodically measuring its local link change rate, a proposed unified performance metric. We study the proposed adaptive mechanism at different mobility levels, using different mobility models such as random waypoint model, random drunken model, and obstacle mobility model. Simulation results show that our proposed adaptive scheme is less dependent on the underlying mobility models and can further reduce false positive ratio. Copyright © 2006 John Wiley & Sons, Ltd. [source] A simple system for biofilm potential monitoring in drinking waterJOURNAL OF BASIC MICROBIOLOGY, Issue 1 2006Eric Delahaye Dr. SAGEP-EAU DE PARIS produces drinking water for the city of Paris (France). In order to supply a high quality water, one of the main SAGEP's concerns is to monitor the Biofilm Formation Potentials of the produced drinking waters. Biofilm incubators were installed at the outlet of three Water Treatment Plants (WTP). These incubators allowed biofilm formation and quantification in terms of Fixed Total Organic Carbon (FTOC), fixed culturable bacteria (HPC-R2A) and fixed total bacteria. During this study, quantitative differences appeared between the biofilms formed at the outlet of the three WTPs, leading to different classifications of the Biofilm Formation Potentials of the three produced waters, depending on the used parameter for biofilms quantification. This observation underlined the necessity of a multi-parametric approach for the study of biofilms. More generally, our results validated the use of these sturdy stainless steel incubators, highly adapted to industrial field conditions, for the monitoring of Biofilm Formation Potentials in drinking water networks. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Monitoring of DNA breakage in embryonic stages of the African catfish Clarias gariepinus (Burchell, 1822) after exposure to lead nitrate using alkaline comet assayENVIRONMENTAL TOXICOLOGY, Issue 6 2008Alaa G. M. Osman Abstract Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the African catfish Clarias gariepinus. Following exposure to 100, 300, and 500 ,g/L lead nitrate, DNA strand breakage was quantified in embryos at 30, 48, 96, 144, and 168 h post-fertilization (PFS). For quantitative analysis, four commonly used parameters (tail % DNA, %TDNA; head % DNA, %HDNA; tail length, TL; tail moment, TM) were analyzed in 96 nuclei (in triplicates) at each sampling point. The parameter %TDNA revealed highest resolution and lowest variation. A strong correlation between lead concentration, time of exposure, and DNA strand breakage was observed. Here, genotoxicity detected by comet assay preceded the manifested malformations assessed with conventional histology. Qualitative evaluation was carried out using five categories are as follows: undamaged (%TDNA , 10%), low damaged (10% < %TDNA , 25%), median damaged (25 < %TDNA , 50%), highly damaged (50 < %TDNA , 75%), and extremely damaged (%TDNA > 75%) nuclei confirming a dose and time-dependent shift towards increased frequencies of highly and extremely damaged nuclei. A protective capacity provided by a hardened chorion is a an interesting finding in this study as DNA damage in the prehatching stages 30 h-PFS and 48 h-PFS was low in all treatments (qualitative and quantitative analyses). These results clearly show that the comet assay is a sensitive tool for the detection of genotoxicity in vulnerable early life stages of the African catfish and is a method more sensitive than histological parameters for monitoring genotoxic effects. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Novel factor of merit for center-frequency tunable bandpass filters comparisonMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009Emmanuel Pistono Abstract This article presents an improved factor of merit for the comparison of center-frequency tunable bandpass filters. This study draws up a comparison between existing tunable filters for which different commonly used parameters demonstrating their performance are given. A first factor of merit that takes all the major characteristics of such tunable filters into account is introduced. A second factor of merit is proposed to evaluate the filter compactness. These new factors of merit are applied for the comparison of more than 30 recently published papers. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 985,988, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24220 [source] Estimation of relative exposure levels for cellular phone users using a neural networkBIOELECTROMAGNETICS, Issue 6 2006Soo Chan Kim Abstract The wide and growing use of cellular phones has raised questions about the possible health risks associated with radio frequency (RF) electromagnetic fields. It would be helpful for epidemiologists as well as cellular phone users to obtain the relative exposure levels, because the RF exposure level is very difficult to accurately measure and quantify for all individuals. In this study, a neural network model was developed to estimate relative exposure levels on a scale of 0,10 and thus rank the individual risk of exposure using available information. We used parameters such as usage time per day, total usage period, hands-free usage, extension of antenna, specific absorption rate (SAR) of the cellular phone, and flip or folder type, which are related to RF exposure. Using the relative exposure levels obtained from this model, epidemiologists can divide the subjects into exposed and nonexposed groups in a study investigating the relationship between exposure level and brain cancer in the future, provided that more knowledge between the cellular phone usage pattern and the exposure is available. Bioelectromagnetics 27:440,444, 2006. © 2006 Wiley-Liss, Inc. [source] Applicability of Carbazole Migration Indices in Continental Rift Basins: A Case Study of Western Lujiapu Depression in Kailu Basin, NE ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2010Shuqing ZHOU Abstract: Kailu Basin in which the Western Lujiapu Depression is located is a typical continental rift basin. Biomarker parameters of the oils indicate that depositional facies and environments vary between the Bao 1 and Bao 14 fault blocks with a higher saline environment in the Bao 1 fault block, but such difference has no significant impact on carbazole abundance and distribution. Maturity and migration distance are the main controls on carbazole abundance and distribution in the Western Lujiapu Depression. The commonly used migration indices, such as ratios of nitrogen shield isomers to nitrogen exposed isomers (1-/4-methylcarbazole ratio, 1,8-/2,4-dimethylcarbazole (DMC) ratio and half-shield/exposed-DMC ratio), absolute concentrations of alkylated carbazoles and BC ratio (= benzo [a]carbazole/ (benzo[a]carbazole + benzo[c]carbazole)) increase at the low mature range and decrease at a higher mature range with increasing maturity. At relatively low maturity stage (Rc<0.77%), maturation has reversal effects with migration on the ratios of nitrogen shield isomers to nitrogen exposed isomers, which may cover migration influence and makes these parameters fail to indicate migration effects. Valid migration indicators at this maturity stage are concentrations of alkylated carbazoles and BC ratios, which can provide ideal tools for migration direction assessment even within short migration distance. Maturity effects should be taken into account when carbazole compounds are applied to indicate migration direction, and at different maturity stages, these commonly used parameters have different validity in tracing migration direction. Coupled with our previous study in the Eastern Lujiapu Depression, a conceptual model of the variation of nitrogen migration indices can be established for terrestrial rifted basins, that is, strong fractionation lateral migration model through sandy beds, weak fractionation vertical migration model along faults, and maturity impacts on migration assessment. [source] | ||||||||||||||||