The moving-window Bayesian Maximum Entropy framework: Estimation of PM2.5 yearly average concentration across the contiguous United States

PubMed Central

Akita, Yasuyuki; Chen, Jiu-Chiuan; Serre, Marc L.

2013-01-01

Geostatistical methods are widely used in estimating long-term exposures for air pollution epidemiological studies, despite their limited capabilities to handle spatial non-stationarity over large geographic domains and uncertainty associated with missing monitoring data. We developed a moving-window (MW) Bayesian Maximum Entropy (BME) method and applied this framework to estimate fine particulate matter (PM2.5) yearly average concentrations over the contiguous U.S. The MW approach accounts for the spatial non-stationarity, while the BME method rigorously processes the uncertainty associated with data missingnees in the air monitoring system. In the cross-validation analyses conducted on a set of randomly selected complete PM2.5 data in 2003 and on simulated data with different degrees of missing data, we demonstrate that the MW approach alone leads to at least 17.8% reduction in mean square error (MSE) in estimating the yearly PM2.5. Moreover, the MWBME method further reduces the MSE by 8.4% to 43.7% with the proportion of incomplete data increased from 18.3% to 82.0%. The MWBME approach leads to significant reductions in estimation error and thus is recommended for epidemiological studies investigating the effect of long-term exposure to PM2.5 across large geographical domains with expected spatial non-stationarity. PMID:22739679

Multi-perspective analysis and spatiotemporal mapping of air pollution monitoring data.

PubMed

Kolovos, Alexander; Skupin, André; Jerrett, Michael; Christakos, George

2010-09-01

Space-time data analysis and assimilation techniques in atmospheric sciences typically consider input from monitoring measurements. The input is often processed in a manner that acknowledges characteristics of the measurements (e.g., underlying patterns, fluctuation features) under conditions of uncertainty; it also leads to the derivation of secondary information that serves study-oriented goals, and provides input to space-time prediction techniques. We present a novel approach that blends a rigorous space-time prediction model (Bayesian maximum entropy, BME) with a cognitively informed visualization of high-dimensional data (spatialization). The combined BME and spatialization approach (BME-S) is used to study monthly averaged NO2 and mean annual SO4 measurements in California over the 15-year period 1988-2002. Using the original scattered measurements of these two pollutants BME generates spatiotemporal predictions on a regular grid across the state. Subsequently, the prediction network undergoes the spatialization transformation into a lower-dimensional geometric representation, aimed at revealing patterns and relationships that exist within the input data. The proposed BME-S provides a powerful spatiotemporal framework to study a variety of air pollution data sources.

An LUR/BME framework to estimate PM2.5 explained by on road mobile and stationary sources.

PubMed

Reyes, Jeanette M; Serre, Marc L

2014-01-01

Knowledge of particulate matter concentrations <2.5 μm in diameter (PM2.5) across the United States is limited due to sparse monitoring across space and time. Epidemiological studies need accurate exposure estimates in order to properly investigate potential morbidity and mortality. Previous works have used geostatistics and land use regression (LUR) separately to quantify exposure. This work combines both methods by incorporating a large area variability LUR model that accounts for on road mobile emissions and stationary source emissions along with data that take into account incompleteness of PM2.5 monitors into the modern geostatistical Bayesian Maximum Entropy (BME) framework to estimate PM2.5 across the United States from 1999 to 2009. A cross-validation was done to determine the improvement of the estimate due to the LUR incorporation into BME. These results were applied to known diseases to determine predicted mortality coming from total PM2.5 as well as PM2.5 explained by major contributing sources. This method showed a mean squared error reduction of over 21.89% oversimple kriging. PM2.5 explained by on road mobile emissions and stationary emissions contributed to nearly 568,090 and 306,316 deaths, respectively, across the United States from 1999 to 2007.

Estimation of Groundwater Radon in North Carolina Using Land Use Regression and Bayesian Maximum Entropy.

PubMed

Messier, Kyle P; Campbell, Ted; Bradley, Philip J; Serre, Marc L

2015-08-18

Radon ((222)Rn) is a naturally occurring chemically inert, colorless, and odorless radioactive gas produced from the decay of uranium ((238)U), which is ubiquitous in rocks and soils worldwide. Exposure to (222)Rn is likely the second leading cause of lung cancer after cigarette smoking via inhalation; however, exposure through untreated groundwater is also a contributing factor to both inhalation and ingestion routes. A land use regression (LUR) model for groundwater (222)Rn with anisotropic geological and (238)U based explanatory variables is developed, which helps elucidate the factors contributing to elevated (222)Rn across North Carolina. The LUR is also integrated into the Bayesian Maximum Entropy (BME) geostatistical framework to increase accuracy and produce a point-level LUR-BME model of groundwater (222)Rn across North Carolina including prediction uncertainty. The LUR-BME model of groundwater (222)Rn results in a leave-one out cross-validation r(2) of 0.46 (Pearson correlation coefficient = 0.68), effectively predicting within the spatial covariance range. Modeled results of (222)Rn concentrations show variability among intrusive felsic geological formations likely due to average bedrock (238)U defined on the basis of overlying stream-sediment (238)U concentrations that is a widely distributed consistently analyzed point-source data.

BME Estimation of Residential Exposure to Ambient PM10 and Ozone at Multiple Time Scales

PubMed Central

Yu, Hwa-Lung; Chen, Jiu-Chiuan; Christakos, George; Jerrett, Michael

2009-01-01

Background Long-term human exposure to ambient pollutants can be an important contributing or etiologic factor of many chronic diseases. Spatiotemporal estimation (mapping) of long-term exposure at residential areas based on field observations recorded in the U.S. Environmental Protection Agency’s Air Quality System often suffer from missing data issues due to the scarce monitoring network across space and the inconsistent recording periods at different monitors. Objective We developed and compared two upscaling methods: UM1 (data aggregation followed by exposure estimation) and UM2 (exposure estimation followed by data aggregation) for the long-term PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) and ozone exposure estimations and applied them in multiple time scales to estimate PM and ozone exposures for the residential areas of the Health Effects of Air Pollution on Lupus (HEAPL) study. Method We used Bayesian maximum entropy (BME) analysis for the two upscaling methods. We performed spatiotemporal cross-validations at multiple time scales by UM1 and UM2 to assess the estimation accuracy across space and time. Results Compared with the kriging method, the integration of soft information by the BME method can effectively increase the estimation accuracy for both pollutants. The spatiotemporal distributions of estimation errors from UM1 and UM2 were similar. The cross-validation results indicated that UM2 is generally better than UM1 in exposure estimations at multiple time scales in terms of predictive accuracy and lack of bias. For yearly PM10 estimations, both approaches have comparable performance, but the implementation of UM1 is associated with much lower computation burden. Conclusion BME-based upscaling methods UM1 and UM2 can assimilate core and site-specific knowledge bases of different formats for long-term exposure estimation. This study shows that UM1 can perform reasonably well when the aggregation process does not alter the spatiotemporal structure of the original data set; otherwise, UM2 is preferable. PMID:19440491

High-resolution spatiotemporal mapping of PM2.5 concentrations at Mainland China using a combined BME-GWR technique

NASA Astrophysics Data System (ADS)

Xiao, Lu; Lang, Yichao; Christakos, George

2018-01-01

With rapid economic development, industrialization and urbanization, the ambient air PM2.5 has become a major pollutant linked to respiratory, heart and lung diseases. In China, PM2.5 pollution constitutes an extreme environmental and social problem of widespread public concern. In this work we estimate ground-level PM2.5 from satellite-derived aerosol optical depth (AOD), topography data, meteorological data, and pollutant emission using an integrative technique. In particular, Geographically Weighted Regression (GWR) analysis was combined with Bayesian Maximum Entropy (BME) theory to assess the spatiotemporal characteristics of PM2.5 exposure in a large region of China and generate informative PM2.5 space-time predictions (estimates). It was found that, due to its integrative character, the combined BME-GWR method offers certain improvements in the space-time prediction of PM2.5 concentrations over China compared to previous techniques. The combined BME-GWR technique generated realistic maps of space-time PM2.5 distribution, and its performance was superior to that of seven previous studies of satellite-derived PM2.5 concentrations in China in terms of prediction accuracy. The purely spatial GWR model can only be used at a fixed time, whereas the integrative BME-GWR approach accounts for cross space-time dependencies and can predict PM2.5 concentrations in the composite space-time domain. The 10-fold results of BME-GWR modeling (R2 = 0.883, RMSE = 11.39 μg /m3) demonstrated a high level of space-time PM2.5 prediction (estimation) accuracy over China, revealing a definite trend of severe PM2.5 levels from the northern coast toward inland China (Nov 2015-Feb 2016). Future work should focus on the addition of higher resolution AOD data, developing better satellite-based prediction models, and related air pollutants for space-time PM2.5 prediction purposes.

Identification of Watershed-scale Critical Source Areas Using Bayesian Maximum Entropy Spatiotemporal Analysis

NASA Astrophysics Data System (ADS)

Roostaee, M.; Deng, Z.

2017-12-01

The states' environmental agencies are required by The Clean Water Act to assess all waterbodies and evaluate potential sources of impairments. Spatial and temporal distributions of water quality parameters are critical in identifying Critical Source Areas (CSAs). However, due to limitations in monetary resources and a large number of waterbodies, available monitoring stations are typically sparse with intermittent periods of data collection. Hence, scarcity of water quality data is a major obstacle in addressing sources of pollution through management strategies. In this study spatiotemporal Bayesian Maximum Entropy method (BME) is employed to model the inherent temporal and spatial variability of measured water quality indicators such as Dissolved Oxygen (DO) concentration for Turkey Creek Watershed. Turkey Creek is located in northern Louisiana and has been listed in 303(d) list for DO impairment since 2014 in Louisiana Water Quality Inventory Reports due to agricultural practices. BME method is proved to provide more accurate estimates than the methods of purely spatial analysis by incorporating space/time distribution and uncertainty in available measured soft and hard data. This model would be used to estimate DO concentration at unmonitored locations and times and subsequently identifying CSAs. The USDA's crop-specific land cover data layers of the watershed were then used to determine those practices/changes that led to low DO concentration in identified CSAs. Primary results revealed that cultivation of corn and soybean as well as urban runoff are main contributing sources in low dissolved oxygen in Turkey Creek Watershed.

Bayesian maximum entropy integration of ozone observations and model predictions: an application for attainment demonstration in North Carolina.

PubMed

de Nazelle, Audrey; Arunachalam, Saravanan; Serre, Marc L

2010-08-01

States in the USA are required to demonstrate future compliance of criteria air pollutant standards by using both air quality monitors and model outputs. In the case of ozone, the demonstration tests aim at relying heavily on measured values, due to their perceived objectivity and enforceable quality. Weight given to numerical models is diminished by integrating them in the calculations only in a relative sense. For unmonitored locations, the EPA has suggested the use of a spatial interpolation technique to assign current values. We demonstrate that this approach may lead to erroneous assignments of nonattainment and may make it difficult for States to establish future compliance. We propose a method that combines different sources of information to map air pollution, using the Bayesian Maximum Entropy (BME) Framework. The approach gives precedence to measured values and integrates modeled data as a function of model performance. We demonstrate this approach in North Carolina, using the State's ozone monitoring network in combination with outputs from the Multiscale Air Quality Simulation Platform (MAQSIP) modeling system. We show that the BME data integration approach, compared to a spatial interpolation of measured data, improves the accuracy and the precision of ozone estimations across the state.

Cost-effective water quality assessment through the integration of monitoring data and modeling results

NASA Astrophysics Data System (ADS)

Lobuglio, Joseph N.; Characklis, Gregory W.; Serre, Marc L.

2007-03-01

Sparse monitoring data and error inherent in water quality models make the identification of waters not meeting regulatory standards uncertain. Additional monitoring can be implemented to reduce this uncertainty, but it is often expensive. These costs are currently a major concern, since developing total maximum daily loads, as mandated by the Clean Water Act, will require assessing tens of thousands of water bodies across the United States. This work uses the Bayesian maximum entropy (BME) method of modern geostatistics to integrate water quality monitoring data together with model predictions to provide improved estimates of water quality in a cost-effective manner. This information includes estimates of uncertainty and can be used to aid probabilistic-based decisions concerning the status of a water (i.e., impaired or not impaired) and the level of monitoring needed to characterize the water for regulatory purposes. This approach is applied to the Catawba River reservoir system in western North Carolina as a means of estimating seasonal chlorophyll a concentration. Mean concentration and confidence intervals for chlorophyll a are estimated for 66 reservoir segments over an 11-year period (726 values) based on 219 measured seasonal averages and 54 model predictions. Although the model predictions had a high degree of uncertainty, integration of modeling results via BME methods reduced the uncertainty associated with chlorophyll estimates compared with estimates made solely with information from monitoring efforts. Probabilistic predictions of future chlorophyll levels on one reservoir are used to illustrate the cost savings that can be achieved by less extensive and rigorous monitoring methods within the BME framework. While BME methods have been applied in several environmental contexts, employing these methods as a means of integrating monitoring and modeling results, as well as application of this approach to the assessment of surface water monitoring networks, represent unexplored areas of research.

Nitrate variability in groundwater of North Carolina using monitoring and private well data models.

PubMed

Messier, Kyle P; Kane, Evan; Bolich, Rick; Serre, Marc L

2014-09-16

Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. Results show significant differences in the spatial distribution of groundwater NO3- contamination in monitoring versus private wells; high NO3- concentrations in the southeastern plains of North Carolina; and wastewater treatment residuals and swine confined animal feeding operations as local sources of NO3- in monitoring wells. Results are of interest to agencies that regulate drinking water sources or monitor health outcomes from ingestion of drinking water. Lastly, LUR-BME model estimates can be integrated into surface water models for more accurate management of nonpoint sources of nitrogen.

Spatiotemporal Characterization of Ambient PM2.5 Concentrations in Shandong Province (China).

PubMed

Yang, Yong; Christakos, George

2015-11-17

China experiences severe particulate matter (PM) pollution problems closely linked to its rapid economic growth. Advancing the understanding and characterization of spatiotemporal air pollution distribution is an area where improved quantitative methods are of great benefit to risk assessment and environmental policy. This work uses the Bayesian maximum entropy (BME) method to assess the space-time variability of PM2.5 concentrations and predict their distribution in the Shandong province, China. Daily PM2.5 concentrations obtained at air quality monitoring sites during 2014 were used. On the basis of the space-time PM2.5 distributions generated by BME, we performed three kinds of querying analysis to reveal the main distribution features. The results showed that the entire region of interest is seriously polluted (BME maps identified heavy pollution clusters during 2014). Quantitative characterization of pollution severity included both pollution level and duration. The number of days during which regional PM2.5 exceeded 75, 115, 150, and 250 μg m(-3) varied: 43-253, 13-128, 4-66, and 0-15 days, respectively. The PM2.5 pattern exhibited an increasing trend from east to west, with the western part of Shandong being a heavily polluted area (PM2.5 exceeded 150 μg m(-3) during long time periods). Pollution was much more serious during winter than during other seasons. Site indicators of PM2.5 pollution intensity and space-time variation were used to assess regional uncertainties and risks with their interpretation depending on the pollutant threshold. The observed PM2.5 concentrations exceeding a specified threshold increased almost linearly with increasing threshold value, whereas the relative probability of excess pollution decreased sharply with increasing threshold.

Development of an Anisotropic Geological-Based Land Use Regression and Bayesian Maximum Entropy Model for Estimating Groundwater Radon across Northing Carolina

NASA Astrophysics Data System (ADS)

Messier, K. P.; Serre, M. L.

2015-12-01

Radon (222Rn) is a naturally occurring chemically inert, colorless, and odorless radioactive gas produced from the decay of uranium (238U), which is ubiquitous in rocks and soils worldwide. Exposure to 222Rn is likely the second leading cause of lung cancer after cigarette smoking via inhalation; however, exposure through untreated groundwater is also a contributing factor to both inhalation and ingestion routes. A land use regression (LUR) model for groundwater 222Rn with anisotropic geological and 238U based explanatory variables is developed, which helps elucidate the factors contributing to elevated 222Rn across North Carolina. Geological and uranium based variables are constructed in elliptical buffers surrounding each observation such that they capture the lateral geometric anisotropy present in groundwater 222Rn. Moreover, geological features are defined at three different geological spatial scales to allow the model to distinguish between large area and small area effects of geology on groundwater 222Rn. The LUR is also integrated into the Bayesian Maximum Entropy (BME) geostatistical framework to increase accuracy and produce a point-level LUR-BME model of groundwater 222Rn across North Carolina including prediction uncertainty. The LUR-BME model of groundwater 222Rn results in a leave-one out cross-validation of 0.46 (Pearson correlation coefficient= 0.68), effectively predicting within the spatial covariance range. Modeled results of 222Rn concentrations show variability among Intrusive Felsic geological formations likely due to average bedrock 238U defined on the basis of overlying stream-sediment 238U concentrations that is a widely distributed consistently analyzed point-source data.

An online spatio-temporal prediction model for dengue fever epidemic in Kaohsiung,Taiwan

NASA Astrophysics Data System (ADS)

Cheng, Ming-Hung; Yu, Hwa-Lung; Angulo, Jose; Christakos, George

2013-04-01

Dengue Fever (DF) is one of the most serious vector-borne infectious diseases in tropical and subtropical areas. DF epidemics occur in Taiwan annually especially during summer and fall seasons. Kaohsiung city has been one of the major DF hotspots in decades. The emergence and re-emergence of the DF epidemic is complex and can be influenced by various factors including space-time dynamics of human and vector populations and virus serotypes as well as the associated uncertainties. This study integrates a stochastic space-time "Susceptible-Infected-Recovered" model under Bayesian maximum entropy framework (BME-SIR) to perform real-time prediction of disease diffusion across space-time. The proposed model is applied for spatiotemporal prediction of the DF epidemic at Kaohsiung city during 2002 when the historical series of high DF cases was recorded. The online prediction by BME-SIR model updates the parameters of SIR model and infected cases across districts over time. Results show that the proposed model is rigorous to initial guess of unknown model parameters, i.e. transmission and recovery rates, which can depend upon the virus serotypes and various human interventions. This study shows that spatial diffusion can be well characterized by BME-SIR model, especially at the district surrounding the disease outbreak locations. The prediction performance at DF hotspots, i.e. Cianjhen and Sanmin, can be degraded due to the implementation of various disease control strategies during the epidemics. The proposed online disease prediction BME-SIR model can provide the governmental agency with a valuable reference to timely identify, control, and efficiently prevent DF spread across space-time.

Estimation of Fine Particulate Matter in Taipei Using Landuse Regression and Bayesian Maximum Entropy Methods

PubMed Central

Yu, Hwa-Lung; Wang, Chih-Hsih; Liu, Ming-Che; Kuo, Yi-Ming

2011-01-01

Fine airborne particulate matter (PM2.5) has adverse effects on human health. Assessing the long-term effects of PM2.5 exposure on human health and ecology is often limited by a lack of reliable PM2.5 measurements. In Taipei, PM2.5 levels were not systematically measured until August, 2005. Due to the popularity of geographic information systems (GIS), the landuse regression method has been widely used in the spatial estimation of PM concentrations. This method accounts for the potential contributing factors of the local environment, such as traffic volume. Geostatistical methods, on other hand, account for the spatiotemporal dependence among the observations of ambient pollutants. This study assesses the performance of the landuse regression model for the spatiotemporal estimation of PM2.5 in the Taipei area. Specifically, this study integrates the landuse regression model with the geostatistical approach within the framework of the Bayesian maximum entropy (BME) method. The resulting epistemic framework can assimilate knowledge bases including: (a) empirical-based spatial trends of PM concentration based on landuse regression, (b) the spatio-temporal dependence among PM observation information, and (c) site-specific PM observations. The proposed approach performs the spatiotemporal estimation of PM2.5 levels in the Taipei area (Taiwan) from 2005–2007. PMID:21776223

Estimation of fine particulate matter in Taipei using landuse regression and bayesian maximum entropy methods.

PubMed

Yu, Hwa-Lung; Wang, Chih-Hsih; Liu, Ming-Che; Kuo, Yi-Ming

2011-06-01

Fine airborne particulate matter (PM2.5) has adverse effects on human health. Assessing the long-term effects of PM2.5 exposure on human health and ecology is often limited by a lack of reliable PM2.5 measurements. In Taipei, PM2.5 levels were not systematically measured until August, 2005. Due to the popularity of geographic information systems (GIS), the landuse regression method has been widely used in the spatial estimation of PM concentrations. This method accounts for the potential contributing factors of the local environment, such as traffic volume. Geostatistical methods, on other hand, account for the spatiotemporal dependence among the observations of ambient pollutants. This study assesses the performance of the landuse regression model for the spatiotemporal estimation of PM2.5 in the Taipei area. Specifically, this study integrates the landuse regression model with the geostatistical approach within the framework of the Bayesian maximum entropy (BME) method. The resulting epistemic framework can assimilate knowledge bases including: (a) empirical-based spatial trends of PM concentration based on landuse regression, (b) the spatio-temporal dependence among PM observation information, and (c) site-specific PM observations. The proposed approach performs the spatiotemporal estimation of PM2.5 levels in the Taipei area (Taiwan) from 2005-2007.

Numerical Demons in Monte Carlo Estimation of Bayesian Model Evidence with Application to Soil Respiration Models

NASA Astrophysics Data System (ADS)

Elshall, A. S.; Ye, M.; Niu, G. Y.; Barron-Gafford, G.

2016-12-01

Bayesian multimodel inference is increasingly being used in hydrology. Estimating Bayesian model evidence (BME) is of central importance in many Bayesian multimodel analysis such as Bayesian model averaging and model selection. BME is the overall probability of the model in reproducing the data, accounting for the trade-off between the goodness-of-fit and the model complexity. Yet estimating BME is challenging, especially for high dimensional problems with complex sampling space. Estimating BME using the Monte Carlo numerical methods is preferred, as the methods yield higher accuracy than semi-analytical solutions (e.g. Laplace approximations, BIC, KIC, etc.). However, numerical methods are prone the numerical demons arising from underflow of round off errors. Although few studies alluded to this issue, to our knowledge this is the first study that illustrates these numerical demons. We show that the precision arithmetic can become a threshold on likelihood values and Metropolis acceptance ratio, which results in trimming parameter regions (when likelihood function is less than the smallest floating point number that a computer can represent) and corrupting of the empirical measures of the random states of the MCMC sampler (when using log-likelihood function). We consider two of the most powerful numerical estimators of BME that are the path sampling method of thermodynamic integration (TI) and the importance sampling method of steppingstone sampling (SS). We also consider the two most widely used numerical estimators, which are the prior sampling arithmetic mean (AS) and posterior sampling harmonic mean (HM). We investigate the vulnerability of these four estimators to the numerical demons. Interesting, the most biased estimator, namely the HM, turned out to be the least vulnerable. While it is generally assumed that AM is a bias-free estimator that will always approximate the true BME by investing in computational effort, we show that arithmetic underflow can hamper AM resulting in severe underestimation of BME. TI turned out to be the most vulnerable, resulting in BME overestimation. Finally, we show how SS can be largely invariant to rounding errors, yielding the most accurate and computational efficient results. These research results are useful for MC simulations to estimate Bayesian model evidence.

Using river distance and existing hydrography data can improve the geostatistical estimation of fish tissue mercury at unsampled locations.

PubMed

Money, Eric S; Sackett, Dana K; Aday, D Derek; Serre, Marc L

2011-09-15

Mercury in fish tissue is a major human health concern. Consumption of mercury-contaminated fish poses risks to the general population, including potentially serious developmental defects and neurological damage in young children. Therefore, it is important to accurately identify areas that have the potential for high levels of bioaccumulated mercury. However, due to time and resource constraints, it is difficult to adequately assess fish tissue mercury on a basin wide scale. We hypothesized that, given the nature of fish movement along streams, an analytical approach that takes into account distance traveled along these streams would improve the estimation accuracy for fish tissue mercury in unsampled streams. Therefore, we used a river-based Bayesian Maximum Entropy framework (river-BME) for modern space/time geostatistics to estimate fish tissue mercury at unsampled locations in the Cape Fear and Lumber Basins in eastern North Carolina. We also compared the space/time geostatistical estimation using river-BME to the more traditional Euclidean-based BME approach, with and without the inclusion of a secondary variable. Results showed that this river-based approach reduced the estimation error of fish tissue mercury by more than 13% and that the median estimate of fish tissue mercury exceeded the EPA action level of 0.3 ppm in more than 90% of river miles for the study domain.

Estimation of typhoon rainfall in GaoPing River: A Multivariate Maximum Entropy Method

NASA Astrophysics Data System (ADS)

Pei-Jui, Wu; Hwa-Lung, Yu

2016-04-01

The heavy rainfall from typhoons is the main factor of the natural disaster in Taiwan, which causes the significant loss of human lives and properties. Statistically average 3.5 typhoons invade Taiwan every year, and the serious typhoon, Morakot in 2009, impacted Taiwan in recorded history. Because the duration, path and intensity of typhoon, also affect the temporal and spatial rainfall type in specific region , finding the characteristics of the typhoon rainfall type is advantageous when we try to estimate the quantity of rainfall. This study developed a rainfall prediction model and can be divided three parts. First, using the EEOF(extended empirical orthogonal function) to classify the typhoon events, and decompose the standard rainfall type of all stations of each typhoon event into the EOF and PC(principal component). So we can classify the typhoon events which vary similarly in temporally and spatially as the similar typhoon types. Next, according to the classification above, we construct the PDF(probability density function) in different space and time by means of using the multivariate maximum entropy from the first to forth moment statistically. Therefore, we can get the probability of each stations of each time. Final we use the BME(Bayesian Maximum Entropy method) to construct the typhoon rainfall prediction model , and to estimate the rainfall for the case of GaoPing river which located in south of Taiwan.This study could be useful for typhoon rainfall predictions in future and suitable to government for the typhoon disaster prevention .

A hybrid approach to estimating national scale spatiotemporal variability of PM2.5 in the contiguous United States.

PubMed

Beckerman, Bernardo S; Jerrett, Michael; Serre, Marc; Martin, Randall V; Lee, Seung-Jae; van Donkelaar, Aaron; Ross, Zev; Su, Jason; Burnett, Richard T

2013-07-02

Airborne fine particulate matter exhibits spatiotemporal variability at multiple scales, which presents challenges to estimating exposures for health effects assessment. Here we created a model to predict ambient particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5) across the contiguous United States to be applied to health effects modeling. We developed a hybrid approach combining a land use regression model (LUR) selected with a machine learning method, and Bayesian Maximum Entropy (BME) interpolation of the LUR space-time residuals. The PM2.5 data set included 104,172 monthly observations at 1464 monitoring locations with approximately 10% of locations reserved for cross-validation. LUR models were based on remote sensing estimates of PM2.5, land use and traffic indicators. Normalized cross-validated R(2) values for LUR were 0.63 and 0.11 with and without remote sensing, respectively, suggesting remote sensing is a strong predictor of ground-level concentrations. In the models including the BME interpolation of the residuals, cross-validated R(2) were 0.79 for both configurations; the model without remotely sensed data described more fine-scale variation than the model including remote sensing. Our results suggest that our modeling framework can predict ground-level concentrations of PM2.5 at multiple scales over the contiguous U.S.

Quantifying bone marrow edema in the rheumatoid cervical spine using magnetic resonance imaging.

PubMed

Suppiah, Ravi; Doyle, Anthony; Rai, Raylynne; Dalbeth, Nicola; Lobo, Maria; Braun, Jürgen; McQueen, Fiona M

2010-08-01

To determine the reliability and feasibility of a new magnetic resonance imaging (MRI) score to quantify bone marrow edema (BME), synovitis, and erosions in the cervical spine of patients with rheumatoid arthritis (RA); and to investigate the correlations among neck pain, clinical markers of RA disease activity, and MRI features of disease activity in the cervical spine. Thirty patients with RA (50% with neck pain) and a Disease Activity Score 28-joint count > 3.2 had an MRI scan of their cervical spine. STIR, VIBE, and T1-weighted postcontrast sequences were used to quantify BME. MRI scans were scored for total BME, synovitis, and erosions using a new scoring method developed by the authors and assessed for reliability and feasibility. Associations between neck pain and clinical markers of disease activity were investigated. BME was present in 14/30 patients; 9/14 (64%) had atlantoaxial BME, 10/14 (71%) had subaxial BME, and 5/14 (36%) had both. Interobserver reliability for total cervical BME score was moderate [intraclass correlation coefficient (ICC) = 0.51]. ICC improved to 0.67 if only the vertebral bodies and dens were considered. There was no correlation between neck pain or clinical measures of RA disease activity and the presence of any MRI features including BME, synovitis, or erosions. Current RA disease activity scores do not identify activity in the cervical spine. An MRI score that quantifies BME, synovitis, and erosions in the cervical spine may provide useful information regarding inflammation and damage. This could alert clinicians to the presence of significant pathology and influence management.

BmeRABC5 is a multidrug efflux system that can confer metronidazole resistance in Bacteroides fragilis.

PubMed

Pumbwe, Lilian; Chang, Abraham; Smith, Rachel L; Wexler, Hannah M

2007-01-01

The RND-family efflux pump gene bmeB5 was previously shown to be overexpressed in metronidazole-resistant laboratory mutants of Bacteroides fragilis. In the present study, we characterized the bmeABC5 genes and an upstream putative TetR-family regulator gene (bmeR5). bmeR5 (645 bp) was located 51 bp upstream of bmeA5 and encoded a 24.9-kDa protein. Deletant strains lacking bmeB5 or bmeR5 were constructed from a wild-type B. fragilis strain ADB77. Strain antimicrobial susceptibility was determined and gene expression was quantified. bmeR5 was overexpressed in Escherichia coli using a 6x-His tag system; BmeR5-His6 was isolated from inclusion bodies and its binding to bmeABC5 promoter regions was determined. BmeR5-His6 bound specifically to the bmeR5-bmeC5 intergenic region (IT1). Deletion of bmeR5 (ADB77DeltabmeR5) resulted in a significant (p < 0.05) increase in expression of bmeA5, bmeB5, and bmeC5, and > two-fold increase in minimum inhibitory concentrations (MICs) of ampicillin, cefoxitin, cefoperazone, ciprofloxacin, imipenem, metronidazole, ethidium bromide, and sodium dodecyl sulfate (SDS). MICs were reduced by the efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The MICs of ampicillin, cefoperazone, metronidazole, and SDS were reduced by approximately two-fold in ADB77DeltabmeB5. A multidrug (metronidazole)-resistant, nim-negative B. fragilis clinical isolate overexpressed bmeABC5 genes, had a G-->T point mutation in IT1, and significantly reduced binding to BmeR5-His6. These data demonstrate that BmeR5 is a local repressor of bmeABC5 expression and that mutations in IT1 can lead to a derepression and resistance to multiple antimicrobial agents, including metronidazole.

An online spatiotemporal prediction model for dengue fever epidemic in Kaohsiung (Taiwan).

PubMed

Yu, Hwa-Lung; Angulo, José M; Cheng, Ming-Hung; Wu, Jiaping; Christakos, George

2014-05-01

The emergence and re-emergence of disease epidemics is a complex question that may be influenced by diverse factors, including the space-time dynamics of human populations, environmental conditions, and associated uncertainties. This study proposes a stochastic framework to integrate space-time dynamics in the form of a Susceptible-Infected-Recovered (SIR) model, together with uncertain disease observations, into a Bayesian maximum entropy (BME) framework. The resulting model (BME-SIR) can be used to predict space-time disease spread. Specifically, it was applied to obtain a space-time prediction of the dengue fever (DF) epidemic that took place in Kaohsiung City (Taiwan) during 2002. In implementing the model, the SIR parameters were continually updated and information on new cases of infection was incorporated. The results obtained show that the proposed model is rigorous to user-specified initial values of unknown model parameters, that is, transmission and recovery rates. In general, this model provides a good characterization of the spatial diffusion of the DF epidemic, especially in the city districts proximal to the location of the outbreak. Prediction performance may be affected by various factors, such as virus serotypes and human intervention, which can change the space-time dynamics of disease diffusion. The proposed BME-SIR disease prediction model can provide government agencies with a valuable reference for the timely identification, control, and prevention of DF spread in space and time. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Strategies to improve engagement of 'hard to reach' older people in research on health promotion: a systematic review.

PubMed

Liljas, Ann E M; Walters, Kate; Jovicic, Ana; Iliffe, Steve; Manthorpe, Jill; Goodman, Claire; Kharicha, Kalpa

2017-04-21

This systematic review aimed to identify facilitators, barriers and strategies for engaging 'hard to reach' older people in research on health promotion; the oldest old (≥80 years), older people from black and minority ethnic groups (BME) and older people living in deprived areas. Eight databases were searched to identify eligible studies using quantitative, qualitative, and mixed research methods. Using elements of narrative synthesis, engagement strategies, and reported facilitators and barriers were identified, tabulated and analysed thematically for each of the three groups of older people. Twenty-three studies (3 with oldest-old, 16 with BME older people, 2 within deprived areas, 1 with both oldest-old and BME, 1 with both BME and deprived areas) were included. Methods included 10 quantitative studies (of which 1 was an RCT), 12 qualitative studies and one mixed-methods study. Facilitators for engaging the oldest old included gaining family support and having flexible sessions. Facilitators for BME groups included building trust through known professionals/community leaders, targeting personal interests, and addressing ethnic and cultural characteristics. Among older people in deprived areas, facilitators for engagement included encouragement by peers and providing refreshments. Across all groups, barriers for engagement were deteriorating health, having other priorities and lack of transport/inaccessibility. Feeling too tired and lacking support from family members were additional barriers for the oldest old. Similarly, feeling too tired and too old to participate in research on health promotion were reported by BME groups. Barriers for BME groups included lack of motivation and self-confidence, and cultural and language differences. Barriers identified in deprived areas included use of written recruitment materials. Strategies to successfully engage with the oldest old included home visits and professionals securing consent if needed. Strategies to engage older people from BME groups included developing community connections and organising social group sessions. Strategies to engage with older people in deprived areas included flexibility in timing and location of interventions. This review identified facilitators, barriers and strategies for engaging 'hard to reach' older people in health promotion but research has been mainly descriptive and there was no high quality evidence on the effectiveness of different approaches.

Impact of temporal upscaling and chemical transport model horizontal resolution on reducing ozone exposure misclassification

NASA Astrophysics Data System (ADS)

Xu, Yadong; Serre, Marc L.; Reyes, Jeanette M.; Vizuete, William

2017-10-01

We have developed a Bayesian Maximum Entropy (BME) framework that integrates observations from a surface monitoring network and predictions from a Chemical Transport Model (CTM) to create improved exposure estimates that can be resolved into any spatial and temporal resolution. The flexibility of the framework allows for input of data in any choice of time scales and CTM predictions of any spatial resolution with varying associated degrees of estimation error and cost in terms of implementation and computation. This study quantifies the impact on exposure estimation error due to these choices by first comparing estimations errors when BME relied on ozone concentration data either as an hourly average, the daily maximum 8-h average (DM8A), or the daily 24-h average (D24A). Our analysis found that the use of DM8A and D24A data, although less computationally intensive, reduced estimation error more when compared to the use of hourly data. This was primarily due to the poorer CTM model performance in the hourly average predicted ozone. Our second analysis compared spatial variability and estimation errors when BME relied on CTM predictions with a grid cell resolution of 12 × 12 km2 versus a coarser resolution of 36 × 36 km2. Our analysis found that integrating the finer grid resolution CTM predictions not only reduced estimation error, but also increased the spatial variability in daily ozone estimates by 5 times. This improvement was due to the improved spatial gradients and model performance found in the finer resolved CTM simulation. The integration of observational and model predictions that is permitted in a BME framework continues to be a powerful approach for improving exposure estimates of ambient air pollution. The results of this analysis demonstrate the importance of also understanding model performance variability and its implications on exposure error.

Evidence for Legacy Contamination of Nitrate in Groundwater of North Carolina Using Monitoring and Private Well Data Models

NASA Astrophysics Data System (ADS)

Messier, K. P.; Kane, E.; Bolich, R.; Serre, M. L.

2014-12-01

Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. Legacy contamination, or past releases of NO3-, is thought to be impacting current groundwater and surface water of North Carolina. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure known as constrained forward nonlinear regression and hyperparameter optimization (CFN-RHO) is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is then used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. The major finding regarding legacy sources NO3- in this study is that the LUR-BME models show the geographical extent of low-level contamination of deeper drinking-water aquifers is beyond that of the shallower monitoring well. Groundwater NO3- in monitoring wells is highly variable with many areas predicted above the current Environmental Protection Agency standard of 10 mg/L. Contrarily, the private well results depict widespread, low-level NO3-concentrations. This evidence supports that in addition to downward transport, there is also a significant outward transport of groundwater NO3- in the drinking water aquifer to areas outside the range of sources. Results indicate that the deeper aquifers are potentially acting as a reservoir that is not only deeper, but also covers a larger geographical area, than the reservoir formed by the shallow aquifers. Results are of interest to agencies that regulate surface water and drinking water sources impacted by the effects of legacy NO3- sources. Additionally, the results can provide guidance on factors affecting the point-level variability of groundwater NO3- and areas where monitoring is needed to reduce uncertainty. Lastly, LUR-BME predictions can be integrated into surface water models for more accurate management of non-point sources of nitrogen.

Bone marrow edema in the knee in osteoarthrosis and association with total knee arthroplasty within a three-year follow-up

PubMed Central

Craig, Joseph; Nelson, Fred

2008-01-01

Objective The purpose of this study was to determine if a correlation exists between magnetic resonance imaging (MRI) findings of bone marrow edema (BME) in osteoarthrosis (OA) of the knee joint and need for total knee arthroplasty (TKA) within a follow-up period of 3 years. Materials and methods The entire database of knee MR studies over a 3-year period was used to select individuals with knee OA. A chart review was conducted to identify and include only those who had a 3-year follow-up appointment from the time of the initial MR study. There were 25 patients in the OA-only group (four men and 21 women; age range, 28–75; average age, 49.3 years). The OA and BME group had 48 patients (23 men and 25 women; average age, 55.5 years). The MRs were reviewed and interpreted by a musculoskeletal radiologist and were classified into one of four patterns of BME: none, focal, global, or cystic pattern. Meniscal tear and degree of cartilage loss were also assessed. Results Subjects who had BME of any pattern type were 8.95 times as likely to progress rapidly to a TKA when compared to subjects with no BME (p = 0.016). Subjects with a global pattern of BME were 5.45 times as likely to have a TKA compared to subjects with focal, cyst, or no BME (p < 0.05). Subjects with a global edema pattern were 13.04 times as likely to have a TKA than subjects with no marrow edema in the knee (p < 0.01). There was no correlation of TKA with meniscal tear or cartilage loss. The group of subjects who had a TKA were 12.6 years older than those who did not have a TKA (p < 0.001). However, the BME results were still significant after accounting for the age difference. Conclusion Our classification of patterns into global, focal, cystic, and absence of BME is an attempt to further define edema in osteoarthrosis and how it relates to clinical progression. Patients with BME and OA have an increased risk of TKA as opposed to OA and no marrow edema. The BME pattern with the worst prognosis for the knee is the global pattern. PMID:18463865

Reliability Evaluation of Base-Metal-Electrode (BME) Multilayer Ceramic Capacitors for Space Applications

NASA Technical Reports Server (NTRS)

Liu, David (Donghang)

2011-01-01

This paper reports reliability evaluation of BME ceramic capacitors for possible high reliability space-level applications. The study is focused on the construction and microstructure of BME capacitors and their impacts on the capacitor life reliability. First, the examinations of the construction and microstructure of commercial-off-the-shelf (COTS) BME capacitors show great variance in dielectric layer thickness, even among BME capacitors with the same rated voltage. Compared to PME (precious-metal-electrode) capacitors, BME capacitors exhibit a denser and more uniform microstructure, with an average grain size between 0.3 and approximately 0.5 micrometers, which is much less than that of most PME capacitors. The primary reasons that a BME capacitor can be fabricated with more internal electrode layers and less dielectric layer thickness is that it has a fine-grained microstructure and does not shrink much during ceramic sintering. This results in the BME capacitors a very high volumetric efficiency. The reliability of BME and PME capacitors was investigated using highly accelerated life testing (HALT) and regular life testing as per MIL-PRF-123. Most BME capacitors were found to fail· with an early dielectric wearout, followed by a rapid wearout failure mode during the HALT test. When most of the early wearout failures were removed, BME capacitors exhibited a minimum mean time-to-failure of more than 10(exp 5) years. Dielectric thickness was found to be a critical parameter for the reliability of BME capacitors. The number of stacked grains in a dielectric layer appears to play a significant role in determining BME capacitor reliability. Although dielectric layer thickness varies for a given rated voltage in BME capacitors, the number of stacked grains is relatively consistent, typically between 10 and 20. This may suggest that the number of grains per dielectric layer is more critical than the thickness itself for determining the rated voltage and the life expectancy of the BME capacitor. Since BME capacitors have a much smaller grain size than PME capacitors, it is reasonable to predict that BME capacitors with thinner dielectric layers may have an equivalent life expectancy to that of PME capacitors with thicker dielectric layers.

Phytochemical comparison between Pet ether and ethanolic extracts of Bacopa monnieri, Evolvulus alsinoides and Tinospora cordifolia.

PubMed

Gupta, Avneet; Raj, Hem; Sharma, Bhartendu; Upmanyu, Neeraj

2014-04-01

Bacopa monnieri, Evolvulus alsinoides and Tinospora cordifolia are established ayurvedic herbs having neuropharmacological effect. In present study is aimed to Phytochemical Comparison between Pet ether and Ethanolic extracts of Bacopa monnieri (BME), Evolvulus alsinoides (EAE) and Tinospora cordifolia (TCE). To identify the presence (+) or absence (-) of different phytoconstituents in Pet ether and Ethanolic extracts of BME, EAE and TCE by using various phytochemical testing methods. Phytochemical investigation showed the presence of various phytochemical constituents in Pet ether and Ethanolic extracts of BME, EAE and TCE. When comparison between Pet ether and Ethanolic extracts of BME, EAE and TCE; Ethanolic extracts of these plants showed more phytoconstituents as compared to Pet ether extracts of these plants. From present investigation, it can be concluded that phytochemical comparison is subsequently momentous and useful in finding chemical constituents in the plant substances that may lead to their quantitative evaluation and also pharmacologically active chemical compounds.

Biomedical Engineering in Modern Society

ERIC Educational Resources Information Center

Attinger, E. O.

1971-01-01

Considers definition of biomedical engineering (BME) and how biomedical engineers should be trained. State of the art descriptions of BME and BME education are followed by a brief look at the future of BME. (TS)

Reliability Evaluation of Base-Metal-Electrode Multilayer Ceramic Capacitors for Potential Space Applications

NASA Technical Reports Server (NTRS)

Liu, David (Donhang); Sampson, Michael J.

2011-01-01

Base-metal-electrode (BME) ceramic capacitors are being investigated for possible use in high-reliability spacelevel applications. This paper focuses on how BME capacitors construction and microstructure affects their lifetime and reliability. Examination of the construction and microstructure of commercial off-the-shelf (COTS) BME capacitors reveals great variance in dielectric layer thickness, even among BME capacitors with the same rated voltage. Compared to PME (precious-metal-electrode) capacitors, BME capacitors exhibit a denser and more uniform microstructure, with an average grain size between 0.3 and 0.5 m, which is much less than that of most PME capacitors. BME capacitors can be fabricated with more internal electrode layers and thinner dielectric layers than PME capacitors because they have a fine-grained microstructure and do not shrink much during ceramic sintering. This makes it possible for BME capacitors to achieve a very high capacitance volumetric efficiency. The reliability of BME and PME capacitors was investigated using highly accelerated life testing (HALT). Most BME capacitors were found to fail with an early avalanche breakdown, followed by a regular dielectric wearout failure during the HALT test. When most of the early failures, characterized with avalanche breakdown, were removed, BME capacitors exhibited a minimum mean time-to-failure (MTTF) of more than 105 years at room temperature and rated voltage. Dielectric thickness was found to be a critical parameter for the reliability of BME capacitors. The number of stacked grains in a dielectric layer appears to play a significant role in determining BME capacitor reliability. Although dielectric layer thickness varies for a given rated voltage in BME capacitors, the number of stacked grains is relatively consistent, typically around 12 for a number of BME capacitors with a rated voltage of 25V. This may suggest that the number of grains per dielectric layer is more critical than the thickness itself for determining the rated voltage and the life expectancy of the BME capacitor. The leakage current characterization and the failure analysis results suggest that most of these early avalanche failures are due to the extrinsic minor construction defects introduced during fabrication of BME capacitors. The concentration of the extrinsic defects must be reduced if the BME capacitors are considered for high reliability applications. There are two approaches that can reduce or prevent the occurrence of early failure in BME capacitors: (1) to reduce the defect concentration with improved processing control; (2) to prevent the use of BME capacitors under harsh external stress levels so that the extrinsic defects will never be triggered for a failure. In order to do so appropriate dielectric layer thickness must be determined for a given rated voltage.

Arsenic in North Carolina: public health implications.

PubMed

Sanders, Alison P; Messier, Kyle P; Shehee, Mina; Rudo, Kenneth; Serre, Marc L; Fry, Rebecca C

2012-01-01

Arsenic is a known human carcinogen and relevant environmental contaminant in drinking water systems. We set out to comprehensively examine statewide arsenic trends and identify areas of public health concern. Specifically, arsenic trends in North Carolina private wells were evaluated over an eleven-year period using the North Carolina Department of Health and Human Services database for private domestic well waters. We geocoded over 63,000 domestic well measurements by applying a novel geocoding algorithm and error validation scheme. Arsenic measurements and geographical coordinates for database entries were mapped using Geographic Information System techniques. Furthermore, we employed a Bayesian Maximum Entropy (BME) geostatistical framework, which accounts for geocoding error to better estimate arsenic values across the state and identify trends for unmonitored locations. Of the approximately 63,000 monitored wells, 7712 showed detectable arsenic concentrations that ranged between 1 and 806μg/L. Additionally, 1436 well samples exceeded the EPA drinking water standard. We reveal counties of concern and demonstrate a historical pattern of elevated arsenic in some counties, particularly those located along the Carolina terrane (Carolina slate belt). We analyzed these data in the context of populations using private well water and identify counties for targeted monitoring, such as Stanly and Union Counties. By spatiotemporally mapping these data, our BME estimate revealed arsenic trends at unmonitored locations within counties and better predicted well concentrations when compared to the classical kriging method. This study reveals relevant information on the location of arsenic-contaminated private domestic wells in North Carolina and indicates potential areas at increased risk for adverse health outcomes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Arsenic in North Carolina: Public Health Implications

PubMed Central

Sanders, Alison P.; Messier, Kyle P.; Shehee, Mina; Rudo, Kenneth; Serre, Marc L.; Fry, Rebecca C.

2012-01-01

Arsenic is a known human carcinogen and relevant environmental contaminant in drinking water systems. We set out to comprehensively examine statewide arsenic trends and identify areas of public health concern. Specifically, arsenic trends in North Carolina private wells were evaluated over an eleven-year period using the North Carolina Department of Health and Human Services (NCDHHS) database for private domestic well waters. We geocoded over 63,000 domestic well measurements by applying a novel geocoding algorithm and error validation scheme. Arsenic measurements and geographical coordinates for database entries were mapped using Geographic Information System (GIS) techniques. Furthermore, we employed a Bayesian Maximum Entropy (BME) geostatistical framework, which accounts for geocoding error to better estimate arsenic values across the state and identify trends for unmonitored locations. Of the approximately 63,000 monitored wells, 7,712 showed detectable arsenic concentrations that ranged between 1 and 806 μg/L. Additionally, 1,436 well samples exceeded the EPA drinking water standard. We reveal counties of concern and demonstrate a historical pattern of elevated arsenic in some counties, particularly those located along the Carolina terrane (Carolina slate belt). We analyzed these data in the context of populations using private well water and identify counties for targeted monitoring, such as Stanly and Union Counties. By spatiotemporally mapping these data, our BME estimate revealed arsenic trends at unmonitored locations within counties and better predicted well concentrations when compared to the classical kriging method. This study reveals relevant information on the location of arsenic-contaminated private domestic wells in North Carolina and indicates potential areas at increased risk for adverse health outcomes. PMID:21982028

Promoting interdisciplinary project-based learning to build the skill sets for research and development of medical devices in academia.

PubMed

Krishnan, Shankar

2013-01-01

The worldwide need for rapid expansion and diversification of medical devices and the corresponding requirements in industry pose arduous challenges for educators to train undergraduate biomedical engineering (BME) students. Preparing BME students for working in the research and development (R&D) in medical device industry is not easily accomplished by adopting traditional pedagogical methods. Even with the inclusion of the design and development elements in capstone projects, medical device industry may be still experience a gap in fulfilling their needs in R&D. This paper proposes a new model based on interdisciplinary project-based learning (IDPBL) to address the requirements of building the necessary skill sets in academia for carrying out R&D in medical device industry. The proposed model incorporates IDPBL modules distributed in a stepwise fashion through the four years of a typical BME program. The proposed model involves buy-in and collaboration from faculty as well as students. The implementation of the proposed design in an undergraduate BME program is still in process. However, a variant of the proposed IDPBL method has been attempted at a limited scale at the postgraduate level and has shown some success. Extrapolating the previous results, the adoption of the IDPBL to BME training seems to suggest promising outcomes. Despite numerous implementation challenges, with continued efforts, the proposed IDPBL will be valuable n academia for skill sets building for medical device R&D.

Promoting harmonization of BME education in Europe: the CRH-BME Tempus project.

PubMed

Pallikarakis, Nicolas; Bliznakov, Zhivko; Miklavcic, Damijan; Jarm, Tomaz; Magjarevic, Ratko; Lackovic, Igor; Pecchia, Leandro; Stagni, Rita; Jobaggy, Akos; Barbenel, Joseph

2011-01-01

Biomedical Engineers should be prepared to adapt to existing or forecasted needs. There is a strong pressure on education, training and life long learning programs to continuously adapt their objectives in order to face new requirements and challenges. The main objective of the TEMPUS IV, CRH-BME project is to update existing curricula in the field of Biomedical Engineering (BME) in order to meet recent and future developments in the area, address new emerging inter-disciplinary domains that appear as a result of the R&D progress and respond to the BME job market demands. The first step is to extensively review the curricula in the BME education field. In this paper, a proposal for a generic curriculum in the BME education is presented, in order to meet recent and future developments and respond to the demands of the BME job market. Adoption of the core program structure will facilitate harmonization of studies as well as student and staff exchange across Europe, thus promoting the European Higher Education Area.

The Significance of Breakdown Voltages for Quality Assurance of Low-Voltage BME Ceramic Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander A.

2014-01-01

Application of thin dielectric, base metal electrode (BME) ceramic capacitors for high-reliability applications requires development of testing procedures that can assure high quality and reliability of the parts. In this work, distributions of breakdown voltages (VBR) in variety of low-voltage BME multilayer ceramic capacitors (MLCCs) have been measured and analyzed. It has been shown that analysis of the distributions can indicate the proportion of defective parts in the lot and significance of the defects. Variations of the distributions after solder dip testing allow for an assessment of the robustness of capacitors to soldering-related stresses. The drawbacks of the existing screening and qualification methods to reveal defects in high-value, low-voltage MLCCs and the importance of VBR measurements are discussed. Analysis has shown that due to a larger concentration of oxygen vacancies, defect-related degradation of the insulation resistance (IR) and failures are more likely in BME compared to the precious metal electrode (PME) capacitors.

Bitter melon extracts enhance the activity of chemotherapeutic agents through the modulation of multiple drug resistance.

PubMed

Kwatra, Deep; Venugopal, Anand; Standing, David; Ponnurangam, Sivapriya; Dhar, Animesh; Mitra, Ashim; Anant, Shrikant

2013-12-01

Recently, we demonstrated that extracts of bitter melon (BME) can be used as a preventive/therapeutic agent in colon cancers. Here, we determined BME effects on anticancer activity and bioavailability of doxorubicin (DOX) in colon cancer cells. BME enhanced the effect of DOX on cell proliferation and sensitized the cells toward DOX upon pretreatment. Furthermore, there was both increased drug uptake and reduced drug efflux. We also observed a reduction in the expression of multidrug resistance conferring proteins (MDRCP) P-glycoprotein, MRP-2, and BCRP. Further BME suppressed DOX efflux in MDCK cells overexpressing the three efflux proteins individually, suggesting that BME is a potent inhibitor of MDR function. Next, we determined the effect of BME on PXR, a xenobiotic sensing nuclear receptor and a transcription factor that controls the expression of the three MDR genes. BME suppressed PXR promoter activity thereby suppressing its expression. Finally, we determined the effect of AMPK pathway on drug efflux because we have previously demonstrated that BME affects the pathway. However, inhibiting AMPK did not affect drug resistance, suggesting that BME may use different pathways for the anticancer and MDR modulating activities. Together, these results suggest that BME can enhance the bioavailability and efficacy of conventional chemotherapy. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Building a more diverse biomedical engineering workforce: Biomedical engineering at the university of the district of Columbia, a historically black college & university.

PubMed

Thompson, Lara A; Adebayo, A Segun; Nian Zhang; Haghani, Sasan; Dowell, Kathleen; Shetty, Devdas

2016-08-01

Biomedical Engineering (BME) is a new, multidisciplinary, and rapidly growing field, however, the BME Workforce suffers from limited ethnic and gender diversity. Despite the demand and growth of this new field due to its public health importance, only 4 out of the 107 Historically Black Colleges and Universities (HBCUs) nationwide offers a Bachelor's of Science (B.S.) in Bio-Engineering related fields. In order to contribute to a growing BME Workforce, HBCUs need to react and offer more degree-programs relevant to BME. At the University of the District of Columbia (UDC), an HBCU and the District's only public institution for higher learning, we have recently established a new, degree program: Bachelor of Science in Biomedical Engineering (B.S. in BME) full-board approved in Fall 2014, with program activities initiated in Fall 2015. The educational goal of this program is to enhance the quality and diversity of the BME Workforce via student professional development, new and relevant BME courses, and BME scholarly activities (e.g., guest lectures and journal club sessions), ultimately to increase the number of ethnic minorities pursuing careers and degrees in BME. Through our program activities, we are aiming to meet the nation's demand to contribute to a diverse BME workforce, directed towards solving problems in human health. A secondary, but related goal, is to increase the diversity of STEM-related fields. This paper summarizes our initial, but encouraging, BME activity-related findings. However, this study will be longitudinal (on a multiple year time period) to observe the true outcomes of our initiative.

Spatial Hearing in Echoic Environments

DTIC Science & Technology

2008-02-29

Erick Gallun Graduate Students: Scott Bressler (Boston University, BME ), Antje Ihlefeld (Boston University, CNS), Kosuke Kawakyu, (MIT, SHBT), Ross...Maddox (Boston University, BME ), Yusuke Naka (Boston University, AME), Erol Ozmeral (Boston University, BME ), Satyavarta (Boston University, CNS...Madhu Shashanka (Boston University, CNS), and Dali Wang (Boston University, BME ) Undergraduates: Sarah Chu (MIT), Eric Larson (Michigan State

Anterior cruciate ligament injury: post-traumatic bone marrow oedema correlates with long-term prognosis.

PubMed

Filardo, Giuseppe; Kon, Elizaveta; Tentoni, Francesco; Andriolo, Luca; Di Martino, Alessandro; Busacca, Maurizio; Di Matteo, Berardo; Marcacci, Maurilio

2016-01-01

Bone marrow oedema (BME) in the knee is a feature of several pathological conditions, and it has been described with high frequency in patients with acute anterior cruciate ligament (ACL) injury. The aim of this study is to evaluate the significance of BME, assessed in MRIs performed for ACL injury, with regards to clinical outcome and return to sport. A total of 134 patients (98 men, 36 women) with ACL tear and MRI knee scan within six months from trauma were analysed. The presence of BME was evaluated on MRI images considering: extension and hyperintensity, the WORMS score oedema classification, and measuring the BME area. The clinical results were documented by IKDC-subjective score and the sport activity level by Tegner score at a minimum of five years follow up. BME was present in 74 knees (55.2 %), with a mean area of 523 ± 370 mm². The presence of BME showed a gradual decrease over time (p = 0.008), being detectable in MRIs performed more than three months after trauma in just 25.0 % of cases. Although 54 % of the patients without BME after three months returned to their previous sport level, no patients with oedema reached a full sport recovery (p = 0.01). In the group that underwent ACL reconstruction, the BME area was significantly correlated with a return to the previous sport level at the mid/long-term follow-up (p = 0.038). BME is a common finding, which decreases over time after injury. However, when BME is still detectable it correlates with clinical prognosis, and even in sport-active patients undergoing ACL reconstruction, a higher BME area is a negative predictive factor for a successful outcome at the mid/long-term follow-up.

Medical Operations Console Procedure Evaluation: BME Response to Crew Call Down for an Emergency

NASA Technical Reports Server (NTRS)

Johnson-Troop; Pettys, Marianne; Hurst, Victor, IV; Smaka, Todd; Paul, Bonnie; Rosenquist, Kevin; Gast, Karin; Gillis, David; McCulley, Phyllis

2006-01-01

International Space Station (ISS) Mission Operations are managed by multiple flight control disciplines located at the lead Mission Control Center (MCC) at NASA-Johnson Space Center (JSC). ISS Medical Operations are supported by the complementary roles of Flight Surgeons (Surgeon) and Biomedical Engineer (BME) flight controllers. The Surgeon, a board certified physician, oversees all medical concerns of the crew and the BME provides operational and engineering support for Medical Operations Crew Health Care System. ISS Medical Operations is currently addressing the coordinated response to a crew call down for an emergent medical event, in particular when the BME is the only Medical Operations representative in MCC. In this case, the console procedure BME Response to Crew Call Down for an Emergency will be used. The procedure instructs the BME to contact a Surgeon as soon as possible, coordinate with other flight disciplines to establish a Private Medical Conference (PMC) for the crew and Surgeon, gather information from the crew if time permits, and provide Surgeon with pertinent console resources. It is paramount that this procedure is clearly written and easily navigated to assist the BME to respond consistently and efficiently. A total of five BME flight controllers participated in the study. Each BME participant sat in a simulated MCC environment at a console configured with resources specific to the BME MCC console and was presented with two scripted emergency call downs from an ISS crew member. Each participant used the procedure while interacting with analog MCC disciplines to respond to the crew call down. Audio and video recordings of the simulations were analyzed and each BME participant's actions were compared to the procedure. Structured debriefs were conducted at the conclusion of both simulations. The procedure was evaluated for its ability to elicit consistent responses from each BME participant. Trials were examined for deviations in procedure task completion and/or navigation, in particular the execution of the Surgeon call sequence. Debrief comments were used to analyze unclear procedural steps and to discern any discrepancies between the procedure and generally accepted BME actions. The sequence followed by BME participants differed considerably from the sequence intended by the procedure. Common deviations included the call sequence used to contact Surgeon, the content of BME and crew interaction and the gathering of pertinent console resources. Differing perceptions of task priority and imprecise language seem to have caused multiple deviations from the procedure s intended sequence. The study generated 40 recommendations for the procedure, of which 34 are being implemented. These recommendations address improving the clarity of the instructions, identifying training considerations, expediting Surgeon contact, improving cues for anticipated flight control team communication and identifying missing console tools.

Understanding the complex interplay of barriers to physical activity amongst black and minority ethnic groups in the United Kingdom: a qualitative synthesis using meta-ethnography.

PubMed

Koshoedo, Sejlo A; Paul-Ebhohimhen, Virginia A; Jepson, Ruth G; Watson, Margaret C

2015-07-12

To conduct a meta-ethnographic analysis of qualitative studies to identify barriers to Black and Minority Ethnic (BME) individuals engaging in physical activity in the UK context. A qualitative synthesis using meta-ethnographic methods to synthesis studies of barriers to engaging in physical activity among BME groups in the UK. A comprehensive search strategy of multiple databases was employed to identify qualitative research studies published up to October 2012. The eleven searched databases included ASSIA, MEDLINE, EMBASE, CINAHL, Health Technology Assessment (HTA), NHS Scotland Library, Physical Activity Health Alliance (PAHA), PsyINFO, Social Services Abstract, Sport discuss and Web of Science. The Noblit and Hare's meta-ethnographic approach was undertaken to develop an inductive and interpretive form of knowledge synthesis. Fourteen papers met the inclusion criteria. The synthesis indicated that barriers to physical activity among BME individuals were influenced by four main concepts: perceptions; cultural expectations; personal barriers; and factors limiting access to facilities. BME individuals had different understandings of physical activity were influenced by migration history, experiences, cultural and health beliefs. This in turn may have a disempowering effect on BME individuals in terms of adopting or maintaining physical activity. These barriers to physical activity were explained at a higher conceptual level by a socio-ecological model. The social construct 'individual perception and understanding of physical activity' was particularly relevant to theoretical models and interventions. Interventions to promote engagement with physical activity need to address perceptions of this behaviour. The elicited concepts and contexts could be used to enhance the development of tailored effective health promotion interventions for BME individuals.

Model selection on solid ground: Rigorous comparison of nine ways to evaluate Bayesian model evidence

PubMed Central

Schöniger, Anneli; Wöhling, Thomas; Samaniego, Luis; Nowak, Wolfgang

2014-01-01

Bayesian model selection or averaging objectively ranks a number of plausible, competing conceptual models based on Bayes' theorem. It implicitly performs an optimal trade-off between performance in fitting available data and minimum model complexity. The procedure requires determining Bayesian model evidence (BME), which is the likelihood of the observed data integrated over each model's parameter space. The computation of this integral is highly challenging because it is as high-dimensional as the number of model parameters. Three classes of techniques to compute BME are available, each with its own challenges and limitations: (1) Exact and fast analytical solutions are limited by strong assumptions. (2) Numerical evaluation quickly becomes unfeasible for expensive models. (3) Approximations known as information criteria (ICs) such as the AIC, BIC, or KIC (Akaike, Bayesian, or Kashyap information criterion, respectively) yield contradicting results with regard to model ranking. Our study features a theory-based intercomparison of these techniques. We further assess their accuracy in a simplistic synthetic example where for some scenarios an exact analytical solution exists. In more challenging scenarios, we use a brute-force Monte Carlo integration method as reference. We continue this analysis with a real-world application of hydrological model selection. This is a first-time benchmarking of the various methods for BME evaluation against true solutions. Results show that BME values from ICs are often heavily biased and that the choice of approximation method substantially influences the accuracy of model ranking. For reliable model selection, bias-free numerical methods should be preferred over ICs whenever computationally feasible. PMID:25745272

Effect of bacoside extract from Bacopa monniera on physical fatigue induced by forced swimming.

PubMed

Anand, T; Phani Kumar, G; Pandareesh, M D; Swamy, M S L; Khanum, Farhath; Bawa, A S

2012-04-01

The antifatigue effect of bacoside extract (BME) from Bacopa monniera (L.) Wettst. was investigated. Rats were subjected to weight-loaded forced swim test (WFST) every alternate day for 3 weeks. The BME at a dosage of 10 mg/kg body weight was administered orally to rats for 2 weeks in order to evaluate the following biomarkers of physical fatigue: swimming time, change in body weight, lipid peroxidation, lactic acid (LA), glycogen, antioxidant enzyme activities such as superoxide dismutase (SOD) and catalase (CAT) and blood parameters, namely blood urea nitrogen (BUN) and creatine kinase (CK). The exhaustive swimming time was increased by 3-fold in the BME supplemented group compared with that of the control group on day 13. The BME treatment lowered malondialdehyde (MDA) levels in brain, liver and muscle tissues by 11.2%, 16.2% and 37.7%, respectively, compared with the control exercised group (p < 0.05). The BME also reduced the LA, serum BUN and CK activities significantly compared with that of the control. Administration of BME significantly protected the depletion of SOD and CAT activities. The HSP-70 expression studies by western blot also confirmed the antifatigue property of BME. The present study thus indicates that BME ameliorates the various impairments associated with physical fatigue. Copyright © 2011 John Wiley & Sons, Ltd.

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket engines' characteristics. This includes BME impacts on vehicle system weight, perfortnance,design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety, performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key Criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket-engines characteristics. This includes BME impacts on vehicle system weight, performance, design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a 'positive MRI'.

PubMed

Laloo, Frederiek; Herregods, N; Jaremko, J L; Verstraete, K; Jans, L

2018-05-01

To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME). A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16-45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated. BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis. Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is 'positive' or 'not positive' for sacroiliitis associated with spondyloarthritis.

Ethnic variations regarding clinical profiles and symptom representation in prisoners with psychotic disorders.

PubMed

Denzel, A Dorina; Harte, Joke M; van den Bergh, Mattis; Scherder, Erik J A

2018-01-01

Black and minority ethnic (BME) groups are known to have higher prevalences of psychotic disorders and are over-represented in western penitentiaries and forensic psychiatric institutions. Research from regular mental healthcare settings suggests that they could show different and more severe psychotic symptoms. Aims To explore ethnic variations in severity of symptomatology of BME and non-BME detainees with psychotic disorders. In this study, 824 patients with psychotic disorders from seven different ethnic groups, imprisoned in a penitentiary psychiatric centre in the Netherlands, were compared on symptom severity and symptom representation using the BPRS-E clinical interview. Data were analysed by means of a multilevel analysis. BME patients with psychotic disorders are over-represented in forensic psychiatry, and symptom profiles of prisoners with psychotic disorders vary by ethnicity. Additionally, severity levels of overall psychopathology differ between ethnic groups: patients with an ethnic majority status show more severe levels of psychopathology compared with BME patients. There are differences in symptom severity and symptom profiles between BME patients and non-BME patients. Disregarding these differences could have an adverse effect on the outcome of the treatment. Possible explanations and clinical impact are discussed. Declaration of interest None.

[Correlation of RANKL/OPG, dickkopf-1 and bone marrow edema in rheumatoid arthritis with the complaint of knee pain].

PubMed

Li, Min; Wu, Xiao-hui; Yin, Geng; Xie, Qi-bing

2015-03-01

To investigate the correlation of the receptor activator of nuclear factor kappa-B ligand (RANKL)/serum osteoprotegerin (OPG) system, Dickkopf-1 (DKK-1) and bone marrow edema (BME) in rheumatoid arthritis (RA) with the complaint of knee pain. The clinical data of 50 cases of RA with the complaint of knee pain were collected. According to MRI finding, half of them (25 cases) had bone marrow edema (BME). Each patient received the measurement of serum OPG, RANKL, DKK-1, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), anti cyclic citrullinated peptide antibody (CCP), rheumatoid factort(RF). The clinical symptoms, disease activity score 28 (DAS28), were compared between BME and non-BME griups, and the correlation between RANKL/OPG system, DKK-1 and BME of RA was analyzed. Compared with non BME group, BME group had shorter course (P=0.000), higher DAS28 score (P=0.009), CRP (P=0:000), RF (P=0.033) and CCP (P=0.012). lower level of serum OPG (P=0.000), higher level of RANKL (P=0.000), RANKL/OPG (P=0.000), and DKK-1 (P=0.001). The severity of bone marrow edema was correlated with the serum RANKL (volume r(s)=0.31, P=0.027; degree r(s)=0.33, P=0.022), RANKL/OPG (volume r(s)=0.29, P=0.039; degree r(s)=0.28, P=0.043), DKK-1 (volume r(s)=0.33, P=0.021; degree r(s)=0.34, P=0.019). BME is one of the early signs of bone erosion in RA, there were more active inflammation, autoantibodies, and osteocasts in RA patients with BME.

Neuroprotective, Neurotrophic and Anti-oxidative Role of Bacopa monnieri on CUS Induced Model of Depression in Rat.

PubMed

Kumar, Sourav; Mondal, Amal Chandra

2016-11-01

Major depression is a life threatening neuropsychiatric disorder that produces mental illness and major cause of morbidity. The present study was conducted to evaluate the neuroprotective, neurotrophic and antioxidant potential of Bacopa monnieri extract (BME) on chronic unpredictable stress (CUS) induced behavioral depression in rats. Behavioral tests were carried out for investigation of antidepressant like effects of BME, and potential mechanism was assessed by determining neurotrophin level and hippocampal neurogenesis. Depressive-like behavior was assessed by shuttle-box escape test, forced swim test and tail suspension test. Effect of BME on hypothalamic-pituitary-adrenal (HPA) axis was evaluated by measuring the plasma level of adrenocorticotropic hormone (ACTH) and corticosterone. The expression of brain derived neurotrophic factor (BDNF), neuronal marker doublecortin (DCX) in the hippocampus were measured and hippocampal neurogenesis was investigated by 5-bromo-2-deoxyuridine/neuronal nuclei (BrdU/NeuN). In addition, effects of BME on oxidative stress markers were also measured in the hippocampus of CUS exposed rats. The results indicated that BME significantly able to attenuate the depressive-like behaviors, normalized the levels of ACTH, corticosterone, and up-regulate the expression of BDNF, DCX and BrdU/NeuN in CUS induced rats compared to BME treated rats. It is also found that BME significantly increased the activity of antioxidant enzymes on CUS induced rats. These findings revealed that BME exerted neuroprotective effects possibly by promoting hippocampal neurogenesis with elevation of BDNF level and antioxidant defense against oxidative stress.

Key Institutions in Business and Management Education Research

ERIC Educational Resources Information Center

Fornaciari, Charles J.; Arbaugh, J. B.; Asarta, Carlos J.; Bento, Regina F.; Hwang, Alvin; Lund Dean, Kathy

2017-01-01

The authors investigate institutional productivity in business and management education (BME) research based on the analysis of 4,464 articles published by 7,210 authors across 17 BME journals over a 10-year period, involving approximately 1,900 schools worldwide. Departing from traditional disciplinary silos, they examine the BME research field…

The New Generation: Characteristics and Motivations of BME Graduate Entrepreneurs

ERIC Educational Resources Information Center

Hussain, Javed G.; Scott, Jonathan M.; Hannon, Paul D.

2008-01-01

Purpose: The purpose of this paper is to profile the characteristics and entrepreneurial motivations of graduate entrepreneurs from black and minority ethnic (BME) communities. Design/methodology/approach: To gather the data, the authors interviewed selected individuals from within the BME community (including current students and graduates from…

First experience with a new biomedical engineering program in Slovenia established following the TEMPUS IV CRH-BME joint project guidelines.

PubMed

Jarm, Tomaz; Miklavcic, Damijan

2014-01-01

A new study program of biomedical engineering was recently established at Faculty of Electrical Engineering, University of Ljubljana, Slovenia. It is based on the long-lasting tradition of education in the field of BME at the host institution and is built on the BME areas in which the research groups of the Faculty of Electrical Engineering have been traditionally successful. The program was prepared in accordance with the recommendations of the TEMPUS IV CRH-BME Project consortium.

Bitter Melon Reduces Head and Neck Squamous Cell Carcinoma Growth by Targeting c-Met Signaling

PubMed Central

Nerurkar, Pratibha; Gonzalez, Juan G.; Crawford, Susan; Varvares, Mark; Ray, Ratna B.

2013-01-01

Head and neck squamous cell carcinoma (HNSCC) remains difficult to treat, and despite of advances in treatment, the overall survival rate has only modestly improved over the past several years. Thus, there is an urgent need for additional therapeutic modalities. We hypothesized that treatment of HNSCC cells with a dietary product such as bitter melon extract (BME) modulates multiple signaling pathways and regresses HNSCC tumor growth in a preclinical model. We observed a reduced cell proliferation in HNSCC cell lines. The mechanistic studies reveal that treatment of BME in HNSCC cells inhibited c-Met signaling pathway. We also observed that BME treatment in HNSCC reduced phosphoStat3, c-myc and Mcl-1 expression, downstream signaling molecules of c-Met. Furthermore, BME treatment in HNSCC cells modulated the expression of key cell cycle progression molecules leading to halted cell growth. Finally, BME feeding in mice bearing HNSCC xenograft tumor resulted in an inhibition of tumor growth and c-Met expression. Together, our results suggested that BME treatment in HNSCC cells modulates multiple signaling pathways and may have therapeutic potential for treating HNSCC. PMID:24147107

Challenges of the biomedical engineering education in Europe.

PubMed

Magjarevic, Ratko; Lackovic, Igor; Bliznakov, Zhivko; Pallikarakis, Nicolas

2010-01-01

Higher education in Europe has passed through a very dynamic period of changes during the last ten years. Since the signing of the Bologna Declaration in 1999 by the Ministers of Education from the EU states, European higher education system has aimed toward establishing harmonized programs enabling students and teachers to extensively exchange knowledge, ideas and skills. Education in the field of Biomedical Engineering has experienced changes also because of the research and development in the field which was more intensive than in other fields. Besides research in new power sources, it is the most intensive and productive research field. Much of the development in BME education in Europe is influenced by the European research policy expressed through the 7th Framework Programme where health is the major theme. In order to foster and support the changes in the European Higher Education Area (EHEA) according to the needs of research sector and the labor market, the Tempus scheme of projects was established. Tempus scheme aims to support the modernization of higher education and create an area of co-operation in the countries surrounding the EU. Our Tempus project, CRH-BME "Curricula Reformation and Harmonization in the field of Biomedical Engineering" aims to create guidelines for updating existing curricula in the field of BME in Europe in order to meet recent and future developments in the area, address new emerging interdisciplinary domains that appear as the result of the R&D progress and respond to the BME job market demands. In this paper, some policy and economic factors affecting BME education in Europe are discussed and the results of a BME education survey we prepared within the Tempus CHR-BME project are presented. The number of BME programmes in Europe has in the last decade significantly increased and there are more BME specializations as the result of growing complexity of the research and production in the field.

Spatiotemporal fusion of multiple-satellite aerosol optical depth (AOD) products using Bayesian maximum entropy method

NASA Astrophysics Data System (ADS)

Tang, Qingxin; Bo, Yanchen; Zhu, Yuxin

2016-04-01

Merging multisensor aerosol optical depth (AOD) products is an effective way to produce more spatiotemporally complete and accurate AOD products. A spatiotemporal statistical data fusion framework based on a Bayesian maximum entropy (BME) method was developed for merging satellite AOD products in East Asia. The advantages of the presented merging framework are that it not only utilizes the spatiotemporal autocorrelations but also explicitly incorporates the uncertainties of the AOD products being merged. The satellite AOD products used for merging are the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Level-2 AOD products (MOD04_L2) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Deep Blue Level 2 AOD products (SWDB_L2). The results show that the average completeness of the merged AOD data is 95.2%,which is significantly superior to the completeness of MOD04_L2 (22.9%) and SWDB_L2 (20.2%). By comparing the merged AOD to the Aerosol Robotic Network AOD records, the results show that the correlation coefficient (0.75), root-mean-square error (0.29), and mean bias (0.068) of the merged AOD are close to those (the correlation coefficient (0.82), root-mean-square error (0.19), and mean bias (0.059)) of the MODIS AOD. In the regions where both MODIS and SeaWiFS have valid observations, the accuracy of the merged AOD is higher than those of MODIS and SeaWiFS AODs. Even in regions where both MODIS and SeaWiFS AODs are missing, the accuracy of the merged AOD is also close to the accuracy of the regions where both MODIS and SeaWiFS have valid observations.

Anti-apoptotic mechanism of Bacoside rich extract against reactive nitrogen species induced activation of iNOS/Bax/caspase 3 mediated apoptosis in L132 cell line.

PubMed

Anand, T; Pandareesh, M D; Bhat, Pratiksha V; Venkataramana, M

2014-10-01

Nitric oxide is a highly reactive free radical gas that reacts with a wide range of bio-molecules to produce reactive nitrogen species and exerts nitrative stress. Bacopa monniera is a traditional folk and ayurvedic medicine known to alleviate a variety of disorders. Aim of the present study is to evaluate the protective propensity of Bacopa monniera extract (BME) through its oxido-nitrosative and anti-apoptotic mechanism to attenuate sodium nitroprusside (SNP)-induced apoptosis in a human embryonic lung epithelial cell line (L132). Our results elucidate that pre-treatment of L132 cells with BME ameliorates the mitochondrial and plasma membrane damage induced by SNP as evidenced by MTT and LDH leakage assays. BME pre-treatment inhibited NO generation by down-regulating inducible nitric oxide synthase expression. BME exhibited potent antioxidant activity by up-regulating the antioxidant enzymes. SNP-induced damage to cellular, nuclear and mitochondrial integrity was also restored by BME, which was confirmed by ROS estimation, comet assay and mitochondrial membrane potential assays respectively. BME pre-treatment efficiently attenuated the SNP-induced apoptotic biomarkers such as Bax, cytochrome-c and caspase-3, which orchestrate the proteolytic damage of the cell. By considering all these findings, we report that BME protects L132 cells against SNP-induced toxicity via its free radical scavenging and anti-apoptotic mechanism.

Proinflammatory responses of a hTERT-transformed, immortalized line of cultured bovine mammary epithelial cells (BME)

USDA-ARS?s Scientific Manuscript database

Primary cultures BME were generated from healthy mammary glands as described (Vet Immunol Immunopath 101(3-4):191-202, 2004). Towards immortalization, BME from four cows were pooled and transfected with pCI neo-hEST2-HA , a human telomerase segment containing a neomycin/Geneticin resistance select...

Bitter Melon (Momordica charantia) Extract Inhibits Tumorigenicity and Overcomes Cisplatin-Resistance in Ovarian Cancer Cells Through Targeting AMPK Signaling Cascade.

PubMed

Yung, Mingo M H; Ross, Fiona A; Hardie, D Grahame; Leung, Thomas H Y; Zhan, Jinbiao; Ngan, Hextan Y S; Chan, David W

2016-09-01

Objective Acquired chemoresistance is a major obstacle in the clinical management of ovarian cancer. Therefore, searching for alternative therapeutic modalities is urgently needed. Bitter melon (Momordica charantia) is a traditional dietary fruit, but its extract also shows potential medicinal values in human diabetes and cancers. Here, we sought to investigate the extract of bitter melon (BME) in antitumorigenic and cisplatin-induced cytotoxicity in ovarian cancer cells. Three varieties of bitter melon were used to prepare the BME. Ovarian cancer cell lines, human immortalized epithelial ovarian cells (HOSEs), and nude mice were used to evaluate the cell cytotoxicity, cisplatin resistance, and tumor inhibitory effect of BME. The molecular mechanism of BME was examined by Western blotting. Cotreatment with BME and cisplatin markedly attenuated tumor growth in vitro and in vivo in a mouse xenograft model, whereas there was no observable toxicity in HOSEs or in nude mice in vivo Interestingly, the antitumorigenic effects of BME varied with different varieties of bitter melon, suggesting that the amount of antitumorigenic substances may vary. Studies of the molecular mechanism demonstrated that BME activates AMP-activated protein kinase (AMPK) in an AMP-independent but CaMKK (Ca(2+)/calmodulin-dependent protein kinase)-dependent manner, exerting anticancer effects through activation of AMPK and suppression of the mTOR/p70S6K and/or the AKT/ERK/FOXM1 (Forkhead Box M1) signaling cascade. BME functions as a natural AMPK activator in the inhibition of ovarian cancer cell growth and might be useful as a supplement to improve the efficacy of cisplatin-based chemotherapy in ovarian cancer. © The Author(s) 2015.

Neuroprotective and anti-apoptotic propensity of Bacopa monniera extract against sodium nitroprusside induced activation of iNOS, heat shock proteins and apoptotic markers in PC12 cells.

PubMed

Pandareesh, M D; Anand, T

2014-05-01

Sodium nitroprusside (SNP) is a widely used nitric oxide (NO) donor, known to exert nitrative stress by up-regulation of inducible nitric oxide synthase (iNOS). Nω-nitro-L-arginine-methyl esther (L-NAME) is a NO inhibitor, which inhibits iNOS expression, is used as positive control. The present study was designed to assess neuroprotective propensity of Bacopa monniera extract (BME) in SNP-induced neuronal damage and oxido-nitrative stress in PC12 cells via modulation of iNOS, heat shock proteins and apoptotic markers. Our results elucidate that pre-treatment of PC12 cells with BME ameliorates the mitochondrial and plasma membrane damage induced by SNP (200 μM) as evidenced by MTT and LDH assays. BME pre-treatment inhibited NO generation by down regulating iNOS expression. BME replenished the depleted antioxidant status induced by SNP treatment. SNP-induced damage to cellular, nuclear and mitochondrial integrity was also restored by BME, which was confirmed by ROS estimation, comet assay and mitochondrial membrane potential assays respectively. BME pre-treatment efficiently attenuated the SNP-induced apoptotic protein biomarkers such as Bax, Bcl-2, cytochrome-c and caspase-3, which orchestrate the proteolytic damage of the cell. Q-PCR results further elucidated up-regulation of neuronal cell stress markers like HO-1 and iNOS and down-regulation of BDNF upon SNP exposure was attenuated by BME pre-treatment. By considering all these findings, we report that BME protects PC12 cells against SNP-induced toxicity via its free radical scavenging and neuroprotective mechanism.

Women Break an Engineering Barrier: While Other Engineering Disciplines Stumble, BME Represents a Success Story in Attracting American Women to a Male-Dominated Field.

PubMed

Gutierrez, Claudia; Paulosky, Meaghan; Aguinaldo, Angeline; Gerhart, Jackie

2017-01-01

While the field of engineering as a whole is largely male-dominated, biomedical engineering (BME) is one area poised to overturn this trend. Women in the United States were awarded only 20% of all engineering B.S. degrees in 2015; in BME, however, 40.9% of the degree recipients were women. This stands in stark contrast to the more traditional fields of mechanical and electrical engineering, where women were awarded just 13.2% and 12.5% of B.S. degrees, respectively. This trend toward more female participation in BME continues at both the M.S. and Ph.D. degree levels. In fact, in 2015, BME had the highest percentage of female engineering M.S. degree recipients in the United States of all engineering disciplines, according to the American Society for Engineering Education (Figure 1).

Characterization of a restriction-modification system of the thermotolerant methylotroph Bacillus methanolicus.

PubMed Central

Cue, D; Lam, H; Hanson, R S; Flickinger, M C

1996-01-01

We report the isolation of a restriction endonuclease, BmeTI, an isoschizomer of BclI, that recognizes the DNA sequence 5' TGATCA 3'. We also report that BmeTI sites are modified to TGm6ATCA. These findings provide the basis for devising strategies to prevent BmeTI restriction of any DNA introduced into Bacillus methanolicus. PMID:8975604

Updating the biomedical engineering curriculum: Inclusion of Health Technology Assessment subjects.

PubMed

Martinez Licona, Fabiola; Urbina, Edmundo Gerardo; Azpiroz-Leehan, Joaquin

2010-01-01

This paper describes the work being carried out at Metropolitan Autonomous University (UAM) in Mexico City with regard to the continuous evaluation and updating of the Biomedical Engineering (BME) curriculum. In particular the courses regarded as part of the BME basic branch are reduced and new sets of elective subjects are proposed in order to bring closer the research work at UAM with the subjects in the BME curriculum. Special emphasis is placed on subjects dealing with Health Technology Assessment (HTA) and Health economics, as this branch of the BME discipline is quite promising in Mexico, but there are very few professionals in the field with adequate qualifications.

The Bombyx mori nucleopolyhedrovirus (BmNPV) ODV-E56 envelope protein is also a per os infectivity factor.

PubMed

Xiang, Xingwei; Chen, Lin; Guo, Aiqin; Yu, Shaofang; Yang, Rui; Wu, Xiaofeng

2011-01-01

The Bombyx mori nucleopolyhedrovirus (BmNPV) odv-e56 gene is a late gene and encodes an occlusion-derived virus (ODV)-specific envelope protein, ODV-E56. To determine its role in the BmNPV life cycle, an odv-e56 null virus, BmE56D, was constructed through homologous recombination. A repaired virus was also constructed, named BmE56DR. The production of budded virion (BV) and polyhedra, the replication of viral DNA, and the morphological of infected BmN cells were analyzed, revealing no significant difference among the BmE56D, the wild-type (WT), and the BmE56DR virus. Larval bioassays demonstrated that injection of BmE56D BV into the hemocoel could kill B. mori larvae as efficiently as repaired and WT viruses, however BmE56D was unable to infect the B. mori larvae when inoculated per os. Thus, these results indicated that ODV-E56 envelope protein of BmNPV is also a per os infectivity factor (PIF), but is not essential for virus replication. Copyright © 2010 Elsevier B.V. All rights reserved.

"You've Got to Be Tough and I'm Trying": Black and Minority Ethnic Student Teachers' Experiences of Initial Teacher Education

ERIC Educational Resources Information Center

Wilkins, Chris; Lall, Rajinder

2011-01-01

Whilst Black and minority ethnic (BME) recruitment to initial teacher education (ITE) in the UK is increasing, completion rates are lower than for White students, and this study reports the experiences of BME student teachers on a primary postgraduate programme that had been particularly successful in increasing recruitment of BME students.…

A standardized extract of Butea monosperma (Lam.) flowers suppresses the IL-1β-induced expression of IL-6 and matrix-metalloproteases by activating autophagy in human osteoarthritis chondrocytes.

PubMed

Ansari, Mohammad Y; Khan, Nazir M; Haqqi, Tariq M

2017-12-01

Osteoarthritis (OA) is a leading cause of joint dysfunction, disability and poor quality of life in the affected population. The underlying mechanism of joint dysfunction involves increased oxidative stress, inflammation, high levels of cartilage extracellular matrix degrading proteases and decline in autophagy-a mechanism of cellular defense. There is no disease modifying therapies currently available for OA. Different parts of the Butea monosperma (Lam.) plant have widely been used in the traditional Indian Ayurvedic medicine system for the treatment of various human diseases including inflammatory conditions. Here we studied the chondroprotective effect of hydromethanolic extract of Butea monosperma (Lam.) flowers (BME) standardized to the concentration of Butein on human OA chondrocytes stimulated with IL-1β. The hydromethanolic extract of Butea monosperma (Lam.) (BME) was prepared with 70% methanol-water mixer using Soxhlet. Chondrocytes viability after BME treatment was measured by MTT assay. Gene expression levels were determined by quantitative polymerase chain reaction (qPCR) using TaqMan assays and immunoblotting with specific antibodies. Autophagy activation was determined by measuring the levels of microtubule associated protein 1 light chain 3-II (LC3-II) by immunoblotting and visualization of autophagosomes by transmission electron and confocal microscopy. BME was non-toxic to the OA chondrocytes at the doses employed and suppressed the IL-1β induced expression of inerleukin-6 (IL-6) and matrix metalloprotease-3 (MMP-3), MMP-9 and MMP-13. BME enhanced autophagy in chondrocytes as determined by measuring the levels of LC3-II by immunoblotting and increased number of autophagosomes in BME treated chondrocytes by transmission electron microscopy and confocal microscopy. BME upregulated the expression of several autophagy related genes and increased the autophagy flux in human OA chondrocytes under pathological conditions. Further analysis revealed that BME activated autophagy in chondrocytes via inhibition of mammalian target of rapamycin (mTOR) pathway. Of importance is our finding that BME-mediated suppression of IL-1β induced expression of IL-6, MMP-3, -9, and -13 was autophagy dependent and was abrogated by inhibition of autophagy. The above results show that the Butea monosperma (Lam.) extract has strong potential to activate autophagy and suppress IL-1β induced expression of IL-6 and MMP-3, -9 and -13 in human OA chondrocytes. This study shows that BME or compounds derived from BME can be developed as safe and effective chondroprotective agent(s) that function by activating autophagy to suppress the expression of inflammatory and catabolic factors associated with OA pathogenesis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Medical Operations Support for ISS Operations - The Role of the BME Operations Team Leads

NASA Technical Reports Server (NTRS)

Janney, Rob; Sabatier, Veronica

2010-01-01

This slide presentation reviews the role of the biomedical flight controllers (BMEs), and BME Operations Team Leads (OTLs) in providing medical support for personnel on the International Space Station. This presentation will concentrate on role of the BME OTLs, who provide the integration function across the integration function across all Crew Health Care System (CHeCS) disciplines for operational products and medical procedures.

Biomedical engineering education at Politecnico di Milano: development and recent changes.

PubMed

Baselli, G

2009-05-01

The biomedical engineering (BME) programme at the Politecnico di Milano (POLIMI) is characterized by a strong interdisciplinary background in a broad range of engineering subjects applied to biology and medicine. Accordingly, the undergraduate level (3 years) provides a general education, which includes mechanics, chemistry and materials, electronics, and information technology both in the context of general engineering and within BME foundations. In contrast, the postgraduate programme (2 years) offers a broad choice of specializations in BME fields in close connection with the BME research activities and laboratories of the campus and with active interchange with the other engineering disciplines. The history of BME development at POLIMI is briefly recalled, together with the characteristics of educational and research work, which is strongly biased by a large polytechnic university with no medical school within the same campus; points of strength and weakness due to this background are discussed. The introduction of a double cycle (undergraduate and postgraduate) according to the Bologna process (2000) and the effects on the programme structure is considered. An early phase in which professional education was emphasized at undergraduate level is recalled, which was followed by the actual revision fostering basic engineering and BME education at the first level while leaving in-depth specialization to postgraduate studies or to on-the-job training.

Attenuation of smoke induced neuronal and physiological changes by bacoside rich extract in Wistar rats via down regulation of HO-1 and iNOS.

PubMed

Pandareesh, M D; Anand, T

2014-01-01

Bacopa monniera is well known herbal medicine for its neuropharmacological effects. It alleviates variety of disorders including neuronal and physiological changes. Crackers smoke is a potent risk factor that leads to free radical mediated oxidative stress in vivo. The aim of the current study is to evaluate the protective efficacy of B. monniera extract (BME) against crackers smoke induced neuronal and physiological changes via modulating inducible nitric oxide synthase (iNOS) and hemeoxygenase-1 (HO-1) expression in rats. Rats were exposed to smoke for 1h for a period of 3 weeks and consecutively treated with BME at three different dosages (i.e., 10, 20 and 40 mg/kg b.wt.). Our results elucidate that BME treatment ameliorates histopathalogical changes, reactive oxygen species levels, lipid peroxidation, acetylcholine esterase activity and brain neurotransmitter levels to normal. BME supplementation efficiently inhibited HO-1 expression and nitric oxide generation by down-regulating iNOS expression. Smoke induced depletion of antioxidant enzyme status, monoamine oxidase activity was also replenished by BME supplementation. Thus the present study indicates that BME ameliorates various impairments associated with neuronal and physiological changes in rats exposed to crackers smoke by its potent neuromodulatory, antioxidant and adaptogenic propensity. Copyright © 2013 Elsevier Inc. All rights reserved.

Neuromodulatory propensity of Bacopa monniera against scopolamine-induced cytotoxicity in PC12 cells via down-regulation of AChE and up-regulation of BDNF and muscarnic-1 receptor expression.

PubMed

Pandareesh, M D; Anand, T

2013-10-01

Scopolamine is a competitive antagonist of muscarinic acetylcholine receptors, and thus classified as an anti-muscarinic and anti-cholinergic drug. PC12 cell lines possess muscarinic receptors and mimic the neuronal cells. These cells were treated with different concentrations of scopolamine for 24 h and were protected from the cellular damage by pretreatment with Bacopa monniera extract (BME). In current study, we have explored the molecular mechanism of neuromodulatory and antioxidant propensity of (BME) to attenuate scopolamine-induced cytotoxicity using PC12 cells. Our results elucidate that pretreatment of PC12 cells with BME ameliorates the mitochondrial and plasma membrane damage induced by 3 μg/ml scopolamine to 54.83 and 30.30 % as evidenced by MTT and lactate dehydrogenase assays respectively. BME (100 μg/ml) ameliorated scopolamine effect by down-regulating acetylcholine esterase and up-regulating brain-derived neurotropic factor and muscarinic muscarinic-1 receptor expression. BME pretreated cells also showed significant protection against scopolamine-induced toxicity by restoring the levels of antioxidant enzymes and lipid peroxidation. This result indicates that the scopolamine-induced cytotoxicity and neuromodulatory changes were restored with the pretreatment of BME.

Clinical outcomes in relation to locations of bone marrow edema lesions in patients with a subchondral insufficiency fracture of the hip: a review of fifteen cases.

PubMed

Ikemura, Satoshi; Mawatari, Taro; Matsui, Gen; Iguchi, Takahiro; Mitsuyasu, Hiroaki

2016-10-01

The prognosis of patients with a subchondral insufficiency fracture remains unclear. The purpose of this study was to investigate the correlation between locations of bone marrow edema (BME) lesions and clinical outcome in patients with a subchondral insufficiency fracture of the hip. We retrospectively reviewed 15 consecutive hips in 14 patients who were diagnosed with subchondral insufficiency fracture of the hip at our institution between April 2013 and September 2014. This study included five males (six hips) and nine females (nine hips), ranging from 36 to 83 years of age (mean age: 66 years). The mean duration from the onset of hip pain to MRI examination was 1.8 months (range 0.5-5 months). Both clinical and imaging findings were investigated. Based on the findings of MR images, BME lesion in the femoral head alone was observed in six patients (six hips), BME lesion in the acetabulum alone was observed in one patient (two hips) and BME lesions in both the femoral head and acetabulum were observed in seven patients (seven hips). 3 of 15 hips resulted in rapidly destructive arthrosis and their BME lesions were observed in both the femoral head and acetabulum. 8 of 15 hips successfully healed by conservative treatment and BME lesions in 7 of these 8 hips were observed in only the femoral head or acetabulum. The results of this study indicate that the locations of BME lesions (femoral side alone, acetabular side alone or both) may be related to the clinical outcome in patients with a subchondral insufficiency fracture of the hip. Patients with subchondral insufficiency fracture of the hip in whom BME lesions were observed in both the femoral head and acetabulum may have a higher risk to need to undergo total hip arthroplasty.

Using Dispersed Modes During Model Correlation

NASA Technical Reports Server (NTRS)

Stewart, Eric; Hathcock, Megan

2017-01-01

Using model dispersions as a starting point allows us to quickly adjust a model to reflect new test data: a) The analyst does a lot of work before the test to save time post-test. b) Creating 1000s of model dispersions to provide "coarse tuning," then use Attune to provide the "fine tuning." ?Successful model tuning on three structures: a) TAURUS. b) Ares I-X C) Cart (in backup charts). ?Mode weighting factors, matrix norm method, and XOR vs. MAC all play key roles in determining the BME. The BME process will be used on future tests: a) ISPE modal test (ongoing work). b) SLS modal test (mid 2018).

Beneficial effects of Bacopa monnieri extract on opioid induced toxicity.

PubMed

Shahid, Muhammad; Subhan, Fazal; Ullah, Ihsan; Ali, Gowhar; Alam, Javaid; Shah, Rehmat

2016-02-01

The present study examined the hepatotoxicity and nephrotoxicity of morphine and illicit street heroin and their amelioration by a standardized methanolic extract of Bacopa monnieri (L.) (mBME) in rats. Morphine or street heroin was administered at a dose of 20 mg/kg for 14 and 21 days. mBME (40 mg/kg) or ascorbic acid (50 mg/kg) was administered two hours before morphine or street heroin. High performance liquid chromatography (HPLC) was used for the standardization of bacoside-A major components in mBME. The antioxidant potential of mBME was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Administration of morphine and street heroin resulted in marked elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatinine. Histopathological changes induced by morphine and street heroin after 14 days were of reversible nature while treatment for 21 days was associated with irreversible changes. Pretreatment with mBME or ascorbic acid restored the elevation of serum ALT, AST and creatinine and protected liver and kidneys from the toxicological influence of morphine and street heroin. HPLC analysis showed that mBME contained bacoside-A major components i.e. bacoside-A3 (37.5 μg/mg), bacopaside-II (4.62 μg/mg) and bacopasaponin-C (1.91 μg/mg). The EC50 for the DPPH free radical scavenging assay revealed that mBME possessed strong antioxidant potential. These results concluded that as compared to morphine, street heroin was associated with severe biochemical and histopathological changes in the liver and kidneys. Bacopa monnieri having strong antioxidant potential may provide a beneficial herbal remedy for the efficient management of opioid related hepatotoxicity and nephrotoxicity.

Biomedical Engineering Curriculum: A Comparison Between the USA, Europe and Australia

DTIC Science & Technology

2001-10-25

Medicine. The Australian course is typically BSc/BE or BE/M( BME )Eng combined degree. The US degrees are often stand alone in terms of employment...opportunities. The Australian degrees tend to provide the graduate with employment opportunities both inside and outside the BME career path. The percentages...genomics for example. The percentages of each Australian U/G course that contains compulsory BME course work varies from 0 to 25%. For the 5 year

Differential effects of β-mercaptoethanol on CdSe/ZnS and InP/ZnS quantum dots.

PubMed

Georgin, Marcel; Carlini, Lina; Cooper, Daniel; Bradforth, Stephen E; Nadeau, Jay L

2013-07-07

The small thiol β-mercaptoethanol (BME) has been used as an anti-blinking reagent for CdSe/ZnS quantum dots (QDs), although its effects on QD photoluminescence are complex. It acts as an antioxidant as well as a hole scavenger on both CdSe and CdTe, which leads to changes in emission intensity and lifetime that vary qualitatively according to BME concentration, time of incubation, and pH of the solution. Because the band edge energies of InP/ZnS are shifted from those of CdTe and CdSe, it may be expected that thiols including BME might be unable to trap holes from these QDs. In this study, we use steady-state and time-resolved emission spectroscopy with physical fitting models combined with blinking analysis to compare the effects of different concentrations of BME on CdSe/ZnS vs. InP/ZnS QDs over time. We also find excellent correspondence between simple physical model parameters and blinking off times, a finding that will be useful for all blinking studies involving semiconductor nanoparticles. BME alters blinking in InP/ZnS QDs with a single ZnS shell, but not those with double thickness shells. The effects are similar to those seen with CdSe/ZnS, despite very different effects of BME on steady-state spectra, and highly pH-dependent.

Cracking Problems and Mechanical Characteristics of PME and BME Ceramic Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2018-01-01

Most failures in MLCCs are caused by cracking that create shorts between opposite electrodes of the parts. A use of manual soldering makes this problem especially serious for space industry. Experience shows that different lots of ceramic capacitors might have different susceptibility to cracking under manual soldering conditions. This simulates a search of techniques that would allow revealing capacitors that are most robust to soldering-induced stresses. Currently, base metal electrode (BME) capacitors are introduced to high-reliability applications as a replacement of precious metal electrode (PME) parts. Understanding the difference in the susceptibility to cracking between PME and BME capacitors would facilitate this process. This presentation gives a review of mechanical characteristics measured in-situ on MLCCs that includes flexural strength, Vickers hardness, indentation fracture toughness, and the board flex testing and compare characteristics of BME and PME capacitors. A history case related to cracking in PME capacitors that caused flight system malfunctions and mechanisms of failure are considered. Possible qualification tests that would allow evaluation of the resistance of MLCCs to manual soldering are suggested and perspectives related to introduction of BME capacitors discussed.

Bayesian Maximum Entropy Integration of Ozone Observations and Model Predictions: A National Application.

PubMed

Xu, Yadong; Serre, Marc L; Reyes, Jeanette; Vizuete, William

2016-04-19

To improve ozone exposure estimates for ambient concentrations at a national scale, we introduce our novel Regionalized Air Quality Model Performance (RAMP) approach to integrate chemical transport model (CTM) predictions with the available ozone observations using the Bayesian Maximum Entropy (BME) framework. The framework models the nonlinear and nonhomoscedastic relation between air pollution observations and CTM predictions and for the first time accounts for variability in CTM model performance. A validation analysis using only noncollocated data outside of a validation radius rv was performed and the R(2) between observations and re-estimated values for two daily metrics, the daily maximum 8-h average (DM8A) and the daily 24-h average (D24A) ozone concentrations, were obtained with the OBS scenario using ozone observations only in contrast with the RAMP and a Constant Air Quality Model Performance (CAMP) scenarios. We show that, by accounting for the spatial and temporal variability in model performance, our novel RAMP approach is able to extract more information in terms of R(2) increase percentage, with over 12 times for the DM8A and over 3.5 times for the D24A ozone concentrations, from CTM predictions than the CAMP approach assuming that model performance does not change across space and time.

University of California, Davis | Division of Cancer Prevention

Cancer.gov

Member Information Dr. Julie L. Sutcliffe Laboratory websiteshttps://bme.ucdavis.edu/sutcliffe/ http://www.ucdmc.ucdavis.edu/publish/providerbio/search/21751 https://bme.ucdavis.edu/people/departmental-faculty/julie-sutcliffe/ |

MRI evidence of structural changes in the sacroiliac joints of patients with non-radiographic axial spondyloarthritis even in the absence of MRI inflammation.

PubMed

Maksymowych, Walter P; Wichuk, Stephanie; Dougados, Maxime; Jones, Heather; Szumski, Annette; Bukowski, Jack F; Marshall, Lisa; Lambert, Robert G

2017-06-06

Studies have shown that structural lesions may be present in patients with non-radiographic axial spondyloarthritis (nr-axSpA). However, the relevance of structural lesions in these patients is unclear, particularly without signs of inflammation on magnetic resonance imaging (MRI). We assessed the presence of structural lesions at baseline on MRI in the sacroiliac joints (SIJ) of patients with nr-axSpA with and without SIJ inflammation on MRI. Bone marrow edema (BME) was assessed on short tau inversion recovery (STIR) scans from 185 patients with nr-axSpA, by two independent readers at baseline using the Spondyloarthritis Research Consortium of Canada (SPARCC) score. Structural lesions were evaluated on T1 weighted spin echo scans, with readers blinded to STIR scans, using the SPARCC MRI SIJ structural score. Disease characteristics and structural lesions were compared in patients with SIJ BME (score ≥2) and without SIJ BME (score <2). Both SIJ BME and structural lesions scores were available for 183 patients; 128/183 (69.9%) patients had SIJ BME scores ≥2 and 55/183 (30.1%) had scores <2. Frequencies of MRI structural lesions in patients with vs without SIJ BME were: erosions (45.3% vs 10.9%, P < 0.001), backfill (20.3% vs 0%, P < 0.001), fat metaplasia (10.9% vs 1.8%, P = 0.04), and ankylosis (2.3% vs 1.8%, P = ns). Significantly more patients with both SIJ BME and structural lesions were male and/or HLA-B27 positive than patients with only SIJ BME. Mean (SD) spinal scores (23 discovertebral units) were significantly higher in patients with SIJ structural lesions than without: 6.5 (11.5) vs 3.3 (5.1), respectively, P = 0.01. In patients with nr-axSpA, SIJ structural lesions, particularly erosions, may be present on MRI when radiographs are normal or inconclusive, even in patients negative for MRI SIJ inflammation. They may reflect more severe disease with greater spinal inflammation. ClinicalTrials.gov, NCT01258738 . Registered on 9 December 2010.

Bayesian model evidence as a model evaluation metric

NASA Astrophysics Data System (ADS)

Guthke, Anneli; Höge, Marvin; Nowak, Wolfgang

2017-04-01

When building environmental systems models, we are typically confronted with the questions of how to choose an appropriate model (i.e., which processes to include or neglect) and how to measure its quality. Various metrics have been proposed that shall guide the modeller towards a most robust and realistic representation of the system under study. Criteria for evaluation often address aspects of accuracy (absence of bias) or of precision (absence of unnecessary variance) and need to be combined in a meaningful way in order to address the inherent bias-variance dilemma. We suggest using Bayesian model evidence (BME) as a model evaluation metric that implicitly performs a tradeoff between bias and variance. BME is typically associated with model weights in the context of Bayesian model averaging (BMA). However, it can also be seen as a model evaluation metric in a single-model context or in model comparison. It combines a measure for goodness of fit with a penalty for unjustifiable complexity. Unjustifiable refers to the fact that the appropriate level of model complexity is limited by the amount of information available for calibration. Derived in a Bayesian context, BME naturally accounts for measurement errors in the calibration data as well as for input and parameter uncertainty. BME is therefore perfectly suitable to assess model quality under uncertainty. We will explain in detail and with schematic illustrations what BME measures, i.e. how complexity is defined in the Bayesian setting and how this complexity is balanced with goodness of fit. We will further discuss how BME compares to other model evaluation metrics that address accuracy and precision such as the predictive logscore or other model selection criteria such as the AIC, BIC or KIC. Although computationally more expensive than other metrics or criteria, BME represents an appealing alternative because it provides a global measure of model quality. Even if not applicable to each and every case, we aim at stimulating discussion about how to judge the quality of hydrological models in the presence of uncertainty in general by dissecting the mechanism behind BME.

Humidity Testing of PME and BME Ceramic Capacitors with Cracks

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander A.; Herzberger, Jaemi

2014-01-01

Cracks in ceramic capacitors are one of the major causes of failures during operation of electronic systems. Humidity testing has been successfully used for many years to verify the absence of cracks and assure quality of military grade capacitors. Traditionally, only precious metal electrode (PME) capacitors were used in high reliability applications and the existing requirements for humidity testing were developed for this type of parts. With the advance of base metal electrode (BME) capacitors, there is a need for assessment of the applicability of the existing techniques for the new technology capacitors. In this work, variety of different PME and BME capacitors with introduced cracks were tested in humid environments at different voltages and temperatures. Analysis of the test results indicates differences in the behavior and failure mechanisms for BME and PME capacitors and the need for different testing conditions.

Cognition Enhancing and Neuromodulatory Propensity of Bacopa monniera Extract Against Scopolamine Induced Cognitive Impairments in Rat Hippocampus.

PubMed

Pandareesh, M D; Anand, T; Khanum, Farhath

2016-05-01

Cognition-enhancing activity of Bacopa monniera extract (BME) was evaluated against scopolamine-induced amnesic rats by novel object recognition test (NOR), elevated plus maze (EPM) and Morris water maze (MWM) tests. Scopolamine (2 mg/kg body wt, i.p.) was used to induce amnesia in rats. Piracetam (200 mg/kg body wt, i.p.) was used as positive control. BME at three different dosages (i.e., 10, 20 and 40 mg/kg body wt.) improved the impairment induced by scopolamine by increasing the discrimination index of NOR and by decreasing the transfer latency of EPM and escape latency of MWM tests. Our results further elucidate that BME administration has normalized the neurotransmitters (acetylcholine, glutamate, 5-hydroxytryptamine, dopamine, 3,4 dihydroxyphenylacetic acid, norepinephrine) levels that were altered by scopolamine administration in hippocampus of rat brain. BME administration also ameliorated scopolamine effect by down-regulating AChE and up-regulating BDNF, muscarinic M1 receptor and CREB expression in brain hippocampus confirms the potent neuroprotective role and these results are in corroboration with the earlier in vitro studies. BME administration showed significant protection against scopolamine-induced toxicity by restoring the levels of antioxidant and lipid peroxidation. These results indicate that, cognition-enhancing and neuromodulatory propensity of BME is through modulating the expression of AChE, BDNF, MUS-1, CREB and also by altering the levels of neurotransmitters in hippocampus of rat brain.

Prophylactic and curative effects of Bacopa monniera in gastric ulcer models.

PubMed

Sairam, K; Rao, C V; Babu, M D; Goel, R K

2001-11-01

Bacopa monniera Wettst. (BM, syn. Herpestis monniera L; Scrophulariaceae), is an Ayurvedic drug used as a rasayana. Its fresh juice was earlier reported to have significant antiulcerogenic activity. In continuation, methanolic extract of BM (BME) standardized to bacoside-A content (percentage-38.0 +/- 0.9), when given in the dose of 10-50 mg/kg, twice daily for 5 days, showed dose-dependent anti-ulcerogenic on various gastric ulcer models induced by ethanol, aspirin, 2 h cold restraint stress and 4 h pylorus ligation. BME in the dose of 20 mg/kg, given for 10 days, twice daily showed healing effects against 50% acetic acid-induced gastric ulcers. Further work was done to investigate the possible mechanisms of its action by studying its effect on various mucosal offensive acid-pepsin secretion and defensive factors like mucin secretion, mucosal cell shedding, cell proliferation and antioxidant activity in rats. BME 20 mg/kg showed no effect on acid-pepsin secretion, increased mucin secretion, while it decreased cell shedding with no effect on cell proliferation. BME showed significant antioxidant effect per se and in stressed animals. Thus, the gastric prophylactic and curative effects of BME may be due to its predominant effect on mucosal defensive factors.

Biomedical engineering continues to make the future.

PubMed

Fantini, Sergio; Bennis, Caoimhe; Kaplan, David

2011-01-01

Biomedical engineering (BME) continues to make the future, not just respond to the present, by anticipating the needs of interface engineering and clinical medicine. In many respects, BME is the educational mode of the future, fostering collaboration among disciplines at its core by building on basic concepts in engineering and biology. We strive to educate where the needs, opportunities, and jobs are and will be in the future. The bridge between engineering, biology, and medicine is a growing link, and there is no sign that this interface will slow. With an aging population, dynamic changes in health care, as well as global economies and related themes upon us, we are only at the very beginning of the impact that BME will have on medicine and the quality of life. Those of us in BME are excited to be setting this agenda and welcome your participation. In part, this is why we have designed our BME major to cover both the depth and breadth, always a challenge, but one that we are committed to. The depth of the design projects, research experience, coursework, study abroad options, and internships all convenes to establish a solid foundation for our students as they embark on their career paths.

Evaluation of In Vivo Wound Healing Activity of Bacopa monniera on Different Wound Model in Rats

PubMed Central

Murthy, S.; Gautam, M. K.; Goel, Shalini; Purohit, V.; Sharma, H.; Goel, R. K.

2013-01-01

Wound healing effects of 50% ethanol extract of dried whole plant of Bacopa monniera (BME) was studied on wound models in rats. BME (25 mg/kg) was administered orally, once daily for 10 days (incision and dead space wound models) or for 21 days or more (excision wound model) in rats. BME was studied for its in vitro antimicrobial and in vivo wound breaking strength, WBS (incision model), rate of contraction, period of epithelization, histology of skin (excision model), granulation tissue free radicals (nitric oxide and lipid peroxidation), antioxidants (catalase, superoxide dismutase, and reduced glutathione), acute inflammatory marker (myeloperoxidase), connective tissue markers (hydroxyproline, hexosamine, and hexuronic acid), and deep connective tissue histology (dead space wound). BME showed antimicrobial activity against skin pathogens, enhanced WBS, rate of contraction, skin collagen tissue formation, and early epithelization period with low scar area indicating enhanced healing. Healing effect was further substantiated by decreased free radicals and myeloperoxidase and enhanced antioxidants and connective tissue markers with histological evidence of more collagen formation in skin and deeper connective tissues. BME decreased myeloperoxidase and free radical generated tissue damage, promoting antioxidant status, faster collagen deposition, other connective tissue constituent formation, and antibacterial activity. PMID:23984424

Bisphosphonates or prostacyclin in the treatment of bone-marrow oedema syndrome of the knee and foot.

PubMed

Baier, Clemens; Schaumburger, Jens; Götz, Jürgen; Heers, Guido; Schmidt, Thorsten; Grifka, Joachim; Beckmann, Johannes

2013-06-01

Bone-marrow oedema (BME) represents a reversible but mostly painful increase in interstitial fluid. The exact pathogenetic processes still remain unknown. Treatment options are mainly symptomatic with core decompression as golden standard leading to immediate pain relieve. Recently, it has been shown that intravenous prostacyclin and bisphosphonates are useful in achieving a reduction in BME with a considerable improvement in the accompanying symptoms. We compared the outcome of both intravenously applied prostacyclin (Ilomedin(®), 10 patients) and bisphosphonate (Bondronat(®), 10 patients) in treatment of BME of the knee and foot. We could find a significant improvement of WOMAC score, SF-36 score and VAS 3 months and 1 year after therapeutic intervention in both the prostacyclin and the bisphosphonate group. Concerning the MRI scans in both groups, we found a distinct reduction of BME in 47 % and a complete regression in 40 %. Comparing both groups, the improvement of the scores was greater in the prostacyclin group than in the bisphosphonate group; the difference, however, was not significant. Intravenous bisphosphonates as well as prostacyclin are of efficient therapeutic benefit in treatment of BME with a quicker and greater effect of prostacyclin.

Evaluation of in vivo wound healing activity of Bacopa monniera on different wound model in rats.

PubMed

Murthy, S; Gautam, M K; Goel, Shalini; Purohit, V; Sharma, H; Goel, R K

2013-01-01

Wound healing effects of 50% ethanol extract of dried whole plant of Bacopa monniera (BME) was studied on wound models in rats. BME (25 mg/kg) was administered orally, once daily for 10 days (incision and dead space wound models) or for 21 days or more (excision wound model) in rats. BME was studied for its in vitro antimicrobial and in vivo wound breaking strength, WBS (incision model), rate of contraction, period of epithelization, histology of skin (excision model), granulation tissue free radicals (nitric oxide and lipid peroxidation), antioxidants (catalase, superoxide dismutase, and reduced glutathione), acute inflammatory marker (myeloperoxidase), connective tissue markers (hydroxyproline, hexosamine, and hexuronic acid), and deep connective tissue histology (dead space wound). BME showed antimicrobial activity against skin pathogens, enhanced WBS, rate of contraction, skin collagen tissue formation, and early epithelization period with low scar area indicating enhanced healing. Healing effect was further substantiated by decreased free radicals and myeloperoxidase and enhanced antioxidants and connective tissue markers with histological evidence of more collagen formation in skin and deeper connective tissues. BME decreased myeloperoxidase and free radical generated tissue damage, promoting antioxidant status, faster collagen deposition, other connective tissue constituent formation, and antibacterial activity.

Understanding Relationships between Health, Ethnicity, Place and the Role of Urban Green Space in Deprived Urban Communities.

PubMed

Roe, Jenny; Aspinall, Peter A; Ward Thompson, Catharine

2016-07-05

Very little is known about how differences in use and perceptions of urban green space impact on the general health of black and minority ethnic (BME) groups. BME groups in the UK suffer from poorer health and a wide range of environmental inequalities that include poorer access to urban green space and poorer quality of green space provision. This study used a household questionnaire (n = 523) to explore the relationship between general health and a range of individual, social and physical environmental predictors in deprived white British and BME groups living in ethnically diverse cities in England. Results from Chi-Squared Automatic Interaction Detection (CHAID) segmentation analyses identified three distinct general health segments in our sample ranging from "very good" health (people of Indian origin), to "good" health (white British), and "poor" health (people of African-Caribbean, Bangladeshi, Pakistani origin and other BME groups), labelled "Mixed BME" in the analyses. Correlated Component Regression analyses explored predictors of general health for each group. Common predictors of general health across all groups were age, disability, and levels of physical activity. However, social and environmental predictors of general health-including use and perceptions of urban green space-varied among the three groups. For white British people, social characteristics of place (i.e., place belonging, levels of neighbourhood trust, loneliness) ranked most highly as predictors of general health, whilst the quality of, access to and the use of urban green space was a significant predictor of general health for the poorest health group only, i.e., in "Mixed BME". Results are discussed from the perspective of differences in use and perceptions of urban green space amongst ethnic groups. We conclude that health and recreation policy in the UK needs to give greater attention to the provision of local green space amongst poor BME communities since this can play an important role in helping address the health inequalities experienced by these groups.

In vitro evaluation of Bacopa monniera on anti-Helicobacter pylori activity and accumulation of prostaglandins.

PubMed

Goel, R K; Sairam, K; Babu, M Dora; Tavares, I A; Raman, A

2003-01-01

Bacopa monniera is an Indian tratidional medicine widely used to improve intellectual functions. Earlier, we had reported the prophylactic and curative effects of standardized extract of Bacopa monniera (BME) in various gastric ulcer models. The effect was due to augmentation of the defensive mucosal factors like increase in mucin secretion, life span of mucosal cells and gastric antioxidant effect rather than on the offensive acid-pepsin secretion. The present study includes evaluation of standardized BME (bacoside A content--35.5 +/- 0.9) on other contributing factors towards ulcerogenesis. BME in the dose of 1000 microg/ml showed anti-Helicobacter pylori activity in vitrol and in the dose of 10 microg/ml increased in vitro of prostanoids (PGE and PGI2) in human colonic mucosal incubates. It may be concluded that these factors may contribute to antiulcerogenic activity of BME.

Design and development of an intelligent nursing bed - a pilot project of "joint assignment".

PubMed

Jiehui Jiang; Tingwei Liu; Yuting Zhang; Yu Song; Mi Zhou; Xiaosong Zheng; Zhuangzhi Yan

2017-07-01

The "joint assignment" is a creative bachelor education project for Biomedical Engineering (BME) in Shanghai University (SHU), China. The objective of this project is to improve students' capabilities in design thinking and teamwork through practices in the process of the design and development of complex medical product. As the first step, a pilot project "design and development of intelligent nursing bed" was set up in May 2015. This paper describes details of how project organization and management, various teaching methods and scientific evaluation approaches were achieved in this pilot project. For example, a method containing one main line and four branches is taken to manage the project and "prototyping model" was used as the main research approach. As a result a multi-win situation was achieved. The results showed, firstly, 62 bachelor students including 16 BME students were well trained. They improved themselves in use of practical tools, communication skills and scientific writing; Secondly, commercial companies received a nice product design on intelligent nursing bed, and have been working on industrializing it; Thirdly, the university and associated schools obtained an excellent practical education experience to supplement traditional class education; Fourthly and most importantly, requirements from end-users will be met. The results also showed that the "joint assignment" task could become a significant component in BME bachelor education.

Comparative evaluation of ethanolic extracts of Bacopa monnieri, Evolvulus alsinoides, Tinospora cordifolia and their combinations on cognitive functions in rats.

PubMed

Gupta, Avneet; Raj, Hem; Karchuli, Manvender Singh; Upmanyu, Neeraj

2013-12-01

The effects of ethanolic extracts of whole plants of Bacopa monnieri (BME), Evolvulus alsinoides (EAE), Tinospora cordifolia (TCE) and their combinations in equal proportion [CEP-1 (BME+EAE), CEP-2 (BME+TCE), CEP-3 (EAE+TCE) and CEP-4 (BME+EAE+TCE)] were tested in amnesic rats using Radial arm maze task performance (RAM) and Barnes maze test at 200 mg/kg p.o. The latency to find food and target hole was observed in RAM and Barnes maze respectively. Cognitive dysfunction was induced by scopolamine (0.3 mg/kg i.p.) treatment. BME, EAE, TCE and their combinations of equal proportion (CEPs) showed significant decrease in latency to find food and target hole in RAM and Barnes maze respectively. Inter comparison among single extract alone treated groups revealed that BME treated animals showed significant difference as compared to EAE and TCE treated animals. All combinations of equal proportion (CEPs) of these extracts showed significant difference in latency to find food and target hole as compared to single extracts treated animals. CEP-1 showed significantly better effect as compared to CEP-2 and CEP-3. Significant difference in latency to find food and target hole was also present between CEP-2 and CEP-3. Effect of CEP-4 was found to be significantly better than CEP-1, CEP-2 and CEP-3 treated rats in both models. From present investigation, it was concluded that ethanolic extract of Bacopa monnieri, Evolvulus alsinoides and Tinospora cordifolia provided better nootropic effect when used in combination.

Biomedical equipment and medical services in India.

PubMed

Sahay, K B; Saxena, R K

Varieties of Biomedical Equipment (BME) are now used for quick diagnosis, flawless surgery and therapeutics etc. Use of a malfunctioning BME could result in faulty diagnosis and wrong treatment and can lead to damaging or even devastating aftermath. Modern Biomedical Equipments inevitably employ highly sophisticated technology and use complex systems and instrumentation for best results. To the best of our knowledge the medical education in India does not impart any knowledge on the theory and design of BME and it is perhaps not possible also. Hence there is need for a permanent mechanism which can maintain and repair the biomedical equipments routinely before use and this can be done only with the help of qualified Clinical Engineers. Thus there is a genuine need for well organized cadre of Clinical Engineers who would be persons with engineering background with specialization in medical instrumentation. These Clinical engineers should be made responsible for the maintenance and proper functioning of BME. Every hospital or group of hospitals in the advanced countries has a clinical engineering unit that takes care of the biomedical equipments and systems in the hospital by undertaking routine and preventive maintenance, regular calibration of equipments and their timely repairs. Clinical engineers should be thus made an essential part of modern health care system and services. Unfortunately such facilities and mechanism do not exist in India. To make BME maintenance efficient and flawless in India, study suggests following measures and remedies: (i) design and development of comprehensive computerized database for BME (ii) cadre of Clinical engineers (iii) online maintenance facility and (iv) farsighted managerial skill to maximize accuracy, functioning and cost effectiveness.

How to Characterize the Reliability of Ceramic Capacitors with Base-Metal Electrodes (BMEs)

NASA Technical Reports Server (NTRS)

Liu, David (Donhang)

2015-01-01

The reliability of an MLCC device is the product of a time-dependent part and a time-independent part: 1) Time-dependent part is a statistical distribution; 2) Time-independent part is the reliability at t=0, the initial reliability. Initial reliability depends only on how a BME MLCC is designed and processed. Similar to the way the minimum dielectric thickness ensured the long-term reliability of a PME MLCC, the initial reliability also ensures the long term-reliability of a BME MLCC. This presentation shows new discoveries regarding commonalities and differences between PME and BME capacitor technologies.

How to Characterize the Reliability of Ceramic Capacitors with Base-Metal Electrodes (BMEs)

NASA Technical Reports Server (NTRS)

Liu, Donhang

2015-01-01

The reliability of an MLCC device is the product of a time-dependent part and a time-independent part: 1) Time-dependent part is a statistical distribution; 2) Time-independent part is the reliability at t0, the initial reliability. Initial reliability depends only on how a BME MLCC is designed and processed. Similar to the way the minimum dielectric thickness ensured the long-term reliability of a PME MLCC, the initial reliability also ensures the long term-reliability of a BME MLCC. This presentation shows new discoveries regarding commonalities and differences between PME and BME capacitor technologies.

Effect of pubic bone marrow edema on recovery from endoscopic surgery for athletic pubalgia.

PubMed

Kuikka, L; Hermunen, H; Paajanen, H

2015-02-01

Athletic pubalgia (sportsman's hernia) is often repaired by surgery. The presence of pubic bone marrow edema (BME) in magnetic resonance imaging (MRI) may effect on the outcome of surgery. Surgical treatment of 30 patients with athletic pubalgia was performed by placement of totally extraperitoneal endoscopic mesh behind the painful groin area. The presence of pre-operative BME was graded from 0 to 3 using MRI and correlated to post-operative pain scores and recovery to sports activity 2 years after operation. The operated athletes participated in our previous prospective randomized study. The athletes with (n = 21) or without (n = 9) pubic BME had similar patients' characteristics and pain scores before surgery. Periostic and intraosseous edema at symphysis pubis was related to increase of post-operative pain scores only at 3 months after surgery (P = 0.03) but not to long-term recovery. Two years after surgery, three athletes in the BME group and three in the normal MRI group needed occasionally pain medication for chronic groin pain, and 87% were playing at the same level as before surgery. This study indicates that the presence of pubic BME had no remarkable long-term effect on recovery from endoscopic surgical treatment of athletic pubalgia. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of Bacopa monniera extract on methylmercury-induced behavioral and histopathological changes in rats.

PubMed

Christinal, Johnson; Sumathi, Thangarajan

2013-10-01

Methylmercury (MeHg) is a well-recognized environmental contaminant with established health risk to human beings by fish and marine mammal consumption. Bacopa monniera (BM) is a perennial herb and is used as a nerve tonic in Ayurveda, a traditional medicine system in India. This study was aimed to evaluate the effect of B. monniera extract (BME) on MeHg-induced toxicity in rat cerebellum. Male Wistar rats were administered with MeHg orally at a dose of 5 mg/kg b.w. for 21 days. Experimental rats were given MeHg and also administered with BME (40 mg/kg, orally) 1 h prior to the administration of MeHg for 21 days. After treatment period, MeHg exposure significantly decreases the body weight and also caused the following behavioral changes. Decrease tail flick response, longer immobility time, significant decrease in motor activity, and spatial short-term memory. BME pretreatment reverted the behavioral changes to normal. MeHg exposure decreases the DNA and RNA content in cerebellum and also caused some pathological changes in cerebellum. Pretreatment with BME restored all the changes to near normal. These findings suggest that BME has a potent efficacy to alleviate MeHg-induced toxicity in rat cerebellum.

Establishment and characterization of three immortal bovine muscular epithelial cell lines.

PubMed

Jin, Xun; Lee, Joong-Seob; Kwak, Sungwook; Lee, Soo-Yeon; Jung, Ji-Eun; Kim, Tae-Kyung; Xu, Chenxiong; Hong, Zhongshan; Li, Zhehu; Kim, Sun-Myung; Pian, Xumin; Lee, Dong-Hee; Yoon, Jong-Taek; You, Seungkwon; Choi, Yun-Jaie; Kim, Huunggee

2006-02-28

We have established three immortal bovine muscular epithelial (BME) cell lines, one spontaneously immortalized (BMES), the second SV40LT-mediated (BMEV) and the third hTERT-mediated (BMET). The morphology of the three immortal cell lines was similar to that of early passage primary BME cells. Each of the immortal cell lines made cytokeratin, a typical epithelial marker. BMET grew faster than the other immortal lines and the BME cells, in 10% FBS-DMEM medium, whereas neither the primary cells nor the three immortal cell lines grew in 0.5% FBS-DMEM. The primary BME cells and the immortal cell lines, with the exception of BMES, made increasing amounts of p53 protein when treated with doxorubicin, a DNA damaging agent. On the other hand, almost half of the cells in populations of the three immortal cell lines may lack p16(INK4a) regulatory function, compared to primary BME cells that were growth arrested by enforced expression of p16(INK4a). In soft-agar assays, the primary cells and immortal cell lines proved to be less transformed in phenotype than HeLa cells. The three immortal epithelial-type cell lines reported here are the first cell lines established from muscle tissue of bovine or other species.

An Approach to Integrating Health Disparities within Undergraduate Biomedical Engineering Education.

PubMed

Vazquez, Maribel; Marte, Otto; Barba, Joseph; Hubbard, Karen

2017-11-01

Health disparities are preventable differences in the incidence, prevalence and burden of disease among communities targeted by gender, geographic location, ethnicity and/or socio-economic status. While biomedical research has identified partial origin(s) of divergent burden and impact of disease, the innovation needed to eradicate health disparities in the United States requires unique engagement from biomedical engineers. Increasing awareness of the prevalence and consequences of health disparities is particularly attractive to today's undergraduates, who have undauntedly challenged paradigms believed to foster inequality. Here, the Department of Biomedical Engineering at The City College of New York (CCNY) has leveraged its historical mission of access-and-excellence to integrate the study of health disparities into undergraduate BME curricula. This article describes our novel approach in a multiyear study that: (i) Integrated health disparities modules at all levels of the required undergraduate BME curriculum; (ii) Developed opportunities to include impacts of health disparities into undergraduate BME research projects and mentored High School summer STEM training; and (iii) Established health disparities-based challenges as BME capstone design and/or independent entrepreneurship projects. Results illustrate the rising awareness of health disparities among the youngest BMEs-to-be, as well as abundant undergraduate desire to integrate health disparities within BME education and training.

Dual-energy imaging of bone marrow edema on a dedicated multi-source cone-beam CT system for the extremities

NASA Astrophysics Data System (ADS)

Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

2015-03-01

Purpose: Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods: Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results: For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Conclusion: Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI.

Dual-Energy Imaging of Bone Marrow Edema on a Dedicated Multi-Source Cone-Beam CT System for the Extremities

PubMed Central

Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

2015-01-01

Purpose Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 – 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Conclusion Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI. PMID:26045631

Evidence of discrimination against BME nurses revealed.

PubMed

Longhurst, Chris

2017-04-27

University of Greenwich researchers responded to an advert from the Nursing and Midwifery Council (NMC) offering funding for an investigation into its fitness-to-practise (FtP) processes amid concerns about the treatment of NHS staff from black and minority ethnic (BME) backgrounds.

Radio protective effect of black mulberry extract on radiation-induced damage in bone marrow cells and liver in the rat

NASA Astrophysics Data System (ADS)

Ghasemnezhad Targhi, Reza; Homayoun, Mansour; Mansouri, Somaieh; Soukhtanloo, Mohammad; Soleymanifard, Shokouhozaman; Seghatoleslam, Masoumeh

2017-01-01

Ionizing radiation by producing free radicals induces tissue oxidative stress and has clastogenic and cytotoxic effects. The radio protective effect of black mulberry extract (BME) has been investigated on liver tissue and bone marrow cells in the rat. Intraperitoneal (ip) administration of 200 mg/kg BME three days before and three days after 3 Gy and 6 Gy gamma irradiation significantly reduced the frequencies of micro nucleated polychromatic erythrocytes (MnPCEs) and micro nucleated norm chromatic erythrocyte (MnNCEs) and increased PCE/PCE+NCE ratio in rat bone marrow compared to the non-treated irradiated groups. Moreover, this concentration of BME extract decreased the level of malondialdehyde (MDA) and superoxide dismutase (SOD), as well as enhanced the total thiol content and catalase activity in rat's liver compared to the non-treated irradiated groups. It seems that BME extract with antioxidant activity reduced the genotoxicity and cytotoxicity induced by gamma irradiation in bone marrow cells and liver in the rat.

Academic program models for undergraduate biomedical engineering.

PubMed

Krishnan, Shankar M

2014-01-01

There is a proliferation of medical devices across the globe for the diagnosis and therapy of diseases. Biomedical engineering (BME) plays a significant role in healthcare and advancing medical technologies thus creating a substantial demand for biomedical engineers at undergraduate and graduate levels. There has been a surge in undergraduate programs due to increasing demands from the biomedical industries to cover many of their segments from bench to bedside. With the requirement of multidisciplinary training within allottable duration, it is indeed a challenge to design a comprehensive standardized undergraduate BME program to suit the needs of educators across the globe. This paper's objective is to describe three major models of undergraduate BME programs and their curricular requirements, with relevant recommendations to be applicable in institutions of higher education located in varied resource settings. Model 1 is based on programs to be offered in large research-intensive universities with multiple focus areas. The focus areas depend on the institution's research expertise and training mission. Model 2 has basic segments similar to those of Model 1, but the focus areas are limited due to resource constraints. In this model, co-op/internship in hospitals or medical companies is included which prepares the graduates for the work place. In Model 3, students are trained to earn an Associate Degree in the initial two years and they are trained for two more years to be BME's or BME Technologists. This model is well suited for the resource-poor countries. All three models must be designed to meet applicable accreditation requirements. The challenges in designing undergraduate BME programs include manpower, facility and funding resource requirements and time constraints. Each academic institution has to carefully analyze its short term and long term requirements. In conclusion, three models for BME programs are described based on large universities, colleges, and community colleges. Model 1 is suitable for research-intensive universities. Models 2 and 3 can be successfully implemented in higher education institutions with low and limited resources with appropriate guidance and support from international organizations. The models will continually evolve mainly to meet the industry needs.

Quantification of Bone Marrow Edema by Magnetic Resonance Imaging Only Marginally Reflects Clinical Neck Pain Evaluation in Rheumatoid Arthritis and Ankylosing Spondylitis.

PubMed

Baraliakos, Xenofon; Heldmann, Frank; Callhoff, Johanna; Suppiah, Ravi; McQueen, Fiona Marion; Krause, Dietmar; Klink, Claudia; Schmitz-Bortz, Elmar; Igelmann, Manfred; Kalthoff, Ludwig; Kiltz, Uta; Schmuedderich, Anna; Braun, Juergen

2016-12-01

Neck pain is common in rheumatoid arthritis (RA) and ankylosing spondylitis (AS). We investigated the correlation of bone marrow edema (BME) on magnetic resonance imaging (MRI) in RA and AS and its association with clinical complaints of neck pain. Cervical spine short-tau inversion recovery-MRI and T1w-MRI of 34 patients with RA and 6 patients with AS complaining about neck pain were obtained. Clinical and laboratory data were available. BME was scored by 2 blinded readers using a modification of a published score, including various cervical sites. Degenerative changes were also quantified. Patients were predominantly women (82.5%), and mean ± SD age was 57.5 ± 11.8 years, C-reactive protein (CRP) was 0.8 ± 1.3 mg/dl, and pain score was 46.0 ± 17.5. BME was detected in 24/40 patients (60%) involving the atlantoaxial region (21%), vertebral bodies (75%), facet joints (29%), and spinous processes (46%). Degenerative changes were identified in 21/40 patients (52.5%), 13 (62%) of whom also had BME in vertebral bodies. No differences were found between patients with versus without cervical BME for clinical assessments: numeric rating scale pain (median ± interquartile range) 5.5 ± 3.0 vs 6.0 ± 4.0 (p = 0.69), Funktionsfragebogen Hannover 68.2 ± 41.0 vs 42.0 ± 55.5 (p = 0.19), Northwick pain score 44.4 ± 21.8 vs 47.2 ± 27.0 (p = 0.83), or CRP 0.40 ± 0.80 vs 0.60 ± 0.66 (p = 0.94). For patients with degenerative changes, symptom duration was longer than for patients without (10 ± 12.5 vs 5.0 ± 18.0 yrs, p = 0.73). In this small study of patients with RA and AS complaining about neck pain, BME was found in many different cervical sites, including the facet joints and the spinous processes. However, the occurrence and severity of BME did not correlate with the severity of neck pain.

Translations on Eastern Europe Scientific Affairs, Number 560

DTIC Science & Technology

1977-10-04

Miklos Szilagyi . TAPNEG; prepares digitalized printed wiring diagram control punch tape on an ADMAP-2 graphing machine with reflection on the x axis...FOKAL 16 KE; BME, Dr Zsolt Illyefalvi-Vitez; BME, Dr Miklos Szilagyi . TESTOP-10; the program provides measurement and diagnostics for logic cards

Cartilage quantification using contrast-enhanced MRI in the wrist of rheumatoid arthritis: cartilage loss is associated with bone marrow edema.

PubMed

Fujimori, Motoshi; Nakamura, Satoko; Hasegawa, Kiminori; Ikeno, Kunihiro; Ichikawa, Shota; Sutherland, Kenneth; Kamishima, Tamotsu

2017-08-01

To quantify wrist cartilage using contrast MRI and compare with the extent of adjacent synovitis and bone marrow edema (BME) in patients with rheumatoid arthritis (RA). 18 patients with RA underwent post-contrast fat-suppressed T 1 weighted coronal imaging. Cartilage area at the centre of the scaphoid-capitate and radius-scaphoid joints was measured by in-house developed software. We defined cartilage as the pixels with signal intensity between two thresholds (lower: 0.4, 0.5 and 0.6 times the muscle signal, upper: 0.9, 1.0, 1.1, 1.2 and 1.3 times the muscle signal). We investigated the association of cartilage loss with synovitis and BME score derived from RA MRI scoring system. Cartilage area was correlated with BME score when thresholds were adequately set with lower threshold at 0.6 times the muscle signal and upper threshold at 1.2 times the muscle signal for both SC (r s =-0.469, p < 0.05) and RS (r s =-0.486, p < 0.05) joints, while it showed no significant correlation with synovitis score at any thresholds. Our software can accurately quantify cartilage in the wrist and BME associated with cartilage loss in patients with RA. Advances in knowledge: Our software can quantify cartilage using conventional MR images of the wrist. BME is associated with cartilage loss in RA patients.

Bestatin Inhibits Cell Growth, Cell Division, and Spore Cell Differentiation in Dictyostelium discoideum

PubMed Central

Poloz, Yekaterina; Catalano, Andrew

2012-01-01

Bestatin methyl ester (BME) is an inhibitor of Zn2+-binding aminopeptidases that inhibits cell proliferation and induces apoptosis in normal and cancer cells. We have used Dictyostelium as a model organism to study the effects of BME. Only two Zn2+-binding aminopeptidases have been identified in Dictyostelium to date, puromycin-sensitive aminopeptidase A and B (PsaA and PsaB). PSA from other organisms is known to regulate cell division and differentiation. Here we show that PsaA is differentially expressed throughout growth and development of Dictyostelium, and its expression is regulated by developmental morphogens. We present evidence that BME specifically interacts with PsaA and inhibits its aminopeptidase activity. Treatment of cells with BME inhibited the rate of cell growth and the frequency of cell division in growing cells and inhibited spore cell differentiation during late development. Overexpression of PsaA-GFP (where GFP is green fluorescent protein) also inhibited spore cell differentiation but did not affect growth. Using chimeras, we have identified that nuclear versus cytoplasmic localization of PsaA affects the choice between stalk or spore cell differentiation pathway. Cells that overexpressed PsaA-GFP (primarily nuclear) differentiated into stalk cells, while cells that overexpressed PsaAΔNLS2-GFP (cytoplasmic) differentiated into spores. In conclusion, we have identified that BME inhibits cell growth, division, and differentiation in Dictyostelium likely through inhibition of PsaA. PMID:22345351

'Our community is the worst': the influence of cultural beliefs on stigma, relationships with family and help-seeking in three ethnic communities in London.

PubMed

Shefer, Guy; Rose, Diana; Nellums, Laura; Thornicroft, Graham; Henderson, Claire; Evans-Lacko, Sara

2013-09-01

Existing knowledge about the cultural beliefs of black and minority ethnic (BME) communities in the UK regarding stigma and mental illness is limited. Data were collected in 10 focus groups, five with service users and five with laypersons, from BME communities in London. Thematic analysis identified that cultural beliefs regarding mental illness reflect four different voices present within the BME communities. The study revealed that cultural beliefs influencing both relationships with family and, consequently, help-seeking for individuals with mental illness must be considered in the development of anti-stigma interventions and when engaging communities around mental health.

Key Authors in Business and Management Education Research: Productivity, Topics, and Future Directions

ERIC Educational Resources Information Center

Arbaugh, J. B.; Asarta, Carlos J.; Hwang, Alvin; Fornaciari, Charles J.; Bento, Regina F.; Dean, Kathy Lund

2017-01-01

Previous studies of author productivity in business and management education (BME) research have focused on single disciplinary areas, and even single journals. This study is the first to examine the productivity of BME scholars across multiple disciplinary areas (i.e., accounting, economics, finance, information systems, management, marketing,…

Possible Involvement of Standardized Bacopa monniera Extract (CDRI-08) in Epigenetic Regulation of reelin and Brain-Derived Neurotrophic Factor to Enhance Memory

PubMed Central

Preethi, Jayakumar; Singh, Hemant K.; Rajan, Koilmani E.

2016-01-01

Bacopa monniera extract (CDRI-08; BME) has been known to improve learning and memory, and understanding the molecular mechanisms may help to know its specificity. We investigated whether the BME treatment alters the methylation status of reelin and brain-derived neurotropic factor (BDNF) to enhance the memory through the interaction of N-methyl-D-aspartate receptor (NMDAR) with synaptic proteins. Rat pups were subjected to novel object recognition test following daily oral administration of BME (80 mg/kg) in 0.5% gum acacia (per-orally, p.o.; PND 15–29)/three doses of 5-azacytidine (5-azaC; 3.2 mg/kg) in 0.9% saline (intraperitoneally, i.p.) on PND-30. After the behavioral test, methylation status of reelin, BDNF and activation of NMDAR, and its interactions with synaptic proteins were tested. Rat pups treated with BME/5-azaC showed higher discrimination towards novel objects than with old objects during testing. Further, we observed an elevated level of unmethylated DNA in reelin and BDNF promoter region. Up-regulated reelin along with the splice variant of apolipoprotein E receptor 2 (ApoER 2, ex 19) form a cluster and activate NMDAR through disabled adopter protein-1 (DAB1) to enhance BDNF. Observed results suggest that BME regulate reelin epigenetically, which might enhance NMDAR interactions with synaptic proteins and induction of BDNF. These changes may be linked with improved novel object recognition memory. PMID:27445807

'He's the dad isn't he?' Gender, race and the politics of prenatal screening.

PubMed

Reed, Kate

2011-01-01

Men's involvement in prenatal screening is becoming increasingly important. However, despite the potentially significant role of fathers in haemoglobinopathy screening, their participation is under researched. Furthermore, the portrayal of Black and minority ethnic (BME) fathers tends to be based on persisting stereotypes of men as either absentee parents with limited roles in screening or as controlling decision-makers. To describe the influence of ethnicity and gender on the process of participation of men in antenatal screening for sickle cell and thalassaemia. A qualitative study, using in-depth interviews and focus groups with 22 pregnant women from a range of socio-economic and ethnic backgrounds, 16 male partners and 15 midwives in a northern city in the UK. Men from BME groups take a pragmatic and equitable role in screening with their partners. White British men on the other hand, while willing to participate in screening, take a more casual view of their own direct participation. Accounts from hospital midwives supported these findings. While acknowledging the importance of material connections between certain BME groups and blood disorders, two key issues are raised. First, BME men's involvement contribute a challenge towards existing assumptions often made about BME fathers. Second, White British men's participation can be useful in determining the genetic status of the foetus and therefore their role should not be neglected. Screening research and practice need to broaden out their focus on issues of gender, ethnicity and screening.

Clinical engineering in Romania. The coming of age.

PubMed

Naianu, B P; Negoescu, R

Biomedical engineering (BME) includes clinical engineering and bioengineering. Bioengineering is academically oriented towards theory and research in biology using the methods of exact sciences such as maths and physics, while clinical engineering (CE) has a rather practical orientation focusing on the general management of clinic/hospital equipment and providing aid to the medical staff in the use of advanced technologies for diagnosis and therapy purposes. The Romanian physiological community has been closely involved in the growth of BME that has now come of age in this country. Radu Vrâncianu's great intuition in opening the door to this science and its practical application in an institution created by Daniel Danielopolu definitely represented a good chance for Romanian public health. Recently, both clinical engineering and medical bioengineering have been introduced into the Romanian Classification of Occupations.

2014 NEPP Tasks Update for Ceramic and Tantalum Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander A.

2014-01-01

Presentation describes recent development in research on MnO2, wet, and polymer tantalum capacitors. Low-voltage failures in multilayer ceramic capacitors and techniques to reveal precious metal electrode (PME) and base metal electrode (BME) capacitors with cracks are discussed. A voltage breakdown technique is suggested to select high quality low-voltage BME ceramic capacitors.

Bone marrow oedema on MR imaging indicates ARCO stage 3 disease in patients with AVN of the femoral head.

PubMed

Meier, Reinhard; Kraus, Tobias M; Schaeffeler, Christoph; Torka, Sebastian; Schlitter, Anna Melissa; Specht, Katja; Haller, Bernhard; Waldt, Simone; Rechl, Hans; Rummeny, Ernst J; Woertler, Klaus

2014-09-01

To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. Thirty-seven symptomatic hips of 27 consecutive patients (53% women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. On MR imaging a fracture line could be identified in 19/37 (51%) cases, which were classified as ARCO stage 3 (n = 15) and stage 4 (n = 4). The remaining 18/37 (49%) cases were classified as ARCO stage 2. However, in all 37/37 (100%) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI (P < 0.05). Histopathological analysis confirmed bone necrosis and subchondral fractures. In patients with AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. BME on MRI in AVN of femoral head indicates a subchondral fracture. BME in AVN of the femoral head represents ARCO stage 3/4 disease. CT identifies subchondral fractures and femoral head collapse better than MR imaging. This knowledge helps to avoid understaging and to trigger adequate treatment.

Neuroprotective effects of Bacopa monniera whole-plant extract against aluminum-induced hippocampus damage in rats: evidence from electron microscopic images.

PubMed

Nannepaga, John Sushma; Korivi, Mallikarjuna; Tirumanyam, Madhavi; Bommavaram, Mahitha; Kuo, Chia-Hua

2014-10-31

Impaired antioxidant system and structural changes in hippocampus are considered as key instigators of neurodegenerative diseases. The present study aimed to investigate the antioxidant and tissue protective properties of Bacopa monniera whole-plant extract (BME) against aluminum (Al)- induced oxidative stress and hippocampus damage in rats. Male Wistar rats were evenly divided into four groups, nine in each and labeled as control, Al treated (10 mg/kg), BME administered (40 mg/kg) and combination of both Al plus BME (Al+BME) treated groups. After one month of treatment by oral administration, antioxidant status was determined, and structural changes in the hippocampus were evaluated by electron microscopy. Al-induced increased oxidative damage in the hippocampus was revealed by elevated thiobarbituric acid reactive substances (TBARS). This increased lipid peroxidation was associated with significantly decreased antioxidant enzyme activities, such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). However, aluminum intoxicated rats treated with BME for 30 days showed significantly restored antioxidant enzyme activities along with decreased TBARS (P < 0.01). Further evidences from electron micrographs clearly indicated that Al-induced vacuolation, lipofuscin deposition and pyramidal cell degeneration in the hippocampus was attenuated with co-administration of the whole-plant extract. Our results demonstrate that structural derangement in hippocampus by aluminum is directly proportionate with increased lipid peroxidation. Nevertheless, B. monniera treatment potentiates the antioxidant status and suppressed the tissue damage induced by Al-intoxication. These findings suggest that B. monniera whole-plant extracts can be considered as a possible remedy to counteract aluminum-associated neurological disorders.

Athletic Pubalgia in Females: Predictive Value of MRI in Outcomes of Endoscopic Surgery

PubMed Central

Matikainen, Markku; Hermunen, Heikki; Paajanen, Hannu

2017-01-01

Background: Athletic pubalgia is typically associated with male athletes participating in contact sports and less frequently with females. Endoscopic surgery may fully treat the patient with athletic pubalgia. Purpose: To perform an outcomes analysis of magnetic resonance imaging (MRI) and endoscopic surgery in female patients with athletic pubalgia. Study Design: Cohort study; Level of evidence, 3. Methods: Fifteen physically active female patients (mean age, 37 years) with athletic pubalgia were treated surgically via placement of total extraperitoneal endoscopic polypropylene mesh behind the injured groin area. The presence of preoperative bone marrow edema (BME) at the pubic symphysis seen on MRI was graded from 0 to 3 and correlated with pain scores after surgery. The outcome measures were pre- and postoperative pain scores and recovery to daily activity between 1 and 12 months after surgery. Results were compared with previously published scores from male athletes (n = 30). Results: With the exception of lower body mass index, the females with (n = 8) and without (n = 7) pubic BME had similar patient characteristics to the corresponding males. Mean inguinal pain scores (0-10) before surgical treatment were greater in females than males (during exercise, 7.8 ± 1.1 vs 6.9 ± 1.1; P = .0131). One month after surgery, mean pain scores for females were still greater compared with males (2.9 ± 1.7 vs 1.3 ± 1.6; P = .0034). Compared with female athletes with normal MRI, pubic BME was related to increased mean preoperative pain scores (8.13 ± 0.99 vs 6.43 ± 1.2; P = .0122). After 1 year, surgical outcomes were excellent or good in 47% of women. Conclusion: Endoscopic surgery was helpful in half of the females with athletic pubalgia in this study. The presence of pubic BME may predict slightly prolonged recovery from surgery. PMID:28840145

Polyhedral geometry of phylogenetic rogue taxa.

PubMed

Cueto, María Angélica; Matsen, Frederick A

2011-06-01

It is well known among phylogeneticists that adding an extra taxon (e.g. species) to a data set can alter the structure of the optimal phylogenetic tree in surprising ways. However, little is known about this "rogue taxon" effect. In this paper we characterize the behavior of balanced minimum evolution (BME) phylogenetics on data sets of this type using tools from polyhedral geometry. First we show that for any distance matrix there exist distances to a "rogue taxon" such that the BME-optimal tree for the data set with the new taxon does not contain any nontrivial splits (bipartitions) of the optimal tree for the original data. Second, we prove a theorem which restricts the topology of BME-optimal trees for data sets of this type, thus showing that a rogue taxon cannot have an arbitrary effect on the optimal tree. Third, we computationally construct polyhedral cones that give complete answers for BME rogue taxon behavior when our original data fits a tree on four, five, and six taxa. We use these cones to derive sufficient conditions for rogue taxon behavior for four taxa, and to understand the frequency of the rogue taxon effect via simulation.

Education of biomedical engineering in Taiwan.

PubMed

Lin, Kang-Ping; Kao, Tsair; Wang, Jia-Jung; Chen, Mei-Jung; Su, Fong-Chin

2014-01-01

Biomedical Engineers (BME) play an important role in medical and healthcare society. Well educational programs are important to support the healthcare systems including hospitals, long term care organizations, manufacture industries of medical devices/instrumentations/systems, and sales/services companies of medical devices/instrumentations/system. In past 30 more years, biomedical engineering society has accumulated thousands people hold a biomedical engineering degree, and work as a biomedical engineer in Taiwan. Most of BME students can be trained in biomedical engineering departments with at least one of specialties in bioelectronics, bio-information, biomaterials or biomechanics. Students are required to have internship trainings in related institutions out of campus for 320 hours before graduating. Almost all the biomedical engineering departments are certified by IEET (Institute of Engineering Education Taiwan), and met the IEET requirement in which required mathematics and fundamental engineering courses. For BMEs after graduation, Taiwanese Society of Biomedical Engineering (TSBME) provides many continue-learning programs and certificates for all members who expect to hold the certification as a professional credit in his working place. In current status, many engineering departments in university are continuously asked to provide joint programs with BME department to train much better quality students. BME is one of growing fields in Taiwan.

Inspiring engineering minds to advance human health: the Henry Samueli School of Engineering's Department of BME.

PubMed

Lee, Abraham; Wirtanen, Erik

2012-07-01

The growth of biomedical engineering at The Henry Samueli School of Engineering at the University of California, Irvine (UCI) has been rapid since the Center for Biomedical Engineering was first formed in 1998 [and was later renamed as the Department of Biomedical Engineering (BME) in 2002]. Our current mission statement, “Inspiring Engineering Minds to Advance Human Health,” serves as a reminder of why we exist, what we do, and the core principles that we value and by which we abide. BME exists to advance the state of human health via engineering innovation and practices. To attain our goal, we are empowering our faculty to inspire and mobilize our students to address health problems. We treasure the human being, particularly the human mind and health. We believe that BME is where minds are nurtured, challenged, and disciplined, and it is also where the health of the human is held as a core mission value that deserves our utmost priority (Figure 1). Advancing human health is not a theoretical practice; it requires bridging between disciplines (engineering and medicine) and between communities (academic and industry).

Leakage Currents in Low-Voltage PME and BME Ceramic Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2015-01-01

Introduction of BME capacitors to high-reliability electronics as a replacement for PME capacitors requires better understanding of changes in performance and reliability of MLCCs to set justified screening and qualification requirements. In this work, absorption and leakage currents in various lots of commercial and military grade X7R MLCCs rated to 100V and less have been measured to reveal difference in behavior of PME and BME capacitors in a wide range of voltages and temperatures. Degradation of leakage currents and failures in virgin capacitors and capacitors with introduced cracks has been studied at different voltages and temperatures during step stress highly accelerated life testing. Mechanisms of charge absorption, conduction and degradation have been discussed and a failure model in capacitors with defects suggested.

Modern space/time geostatistics using river distances: data integration of turbidity and E. coli measurements to assess fecal contamination along the Raritan River in New Jersey.

PubMed

Money, Eric S; Carter, Gail P; Serre, Marc L

2009-05-15

Escherichia coli (E. coli) is a widely used indicator of fecal contamination in water bodies. External contact and subsequent ingestion of bacteria coming from fecal contamination can lead to harmful health effects. Since E. coli data are sometimes limited, the objective of this study is to use secondary information in the form of turbidity to improve the assessment of E. coli at unmonitored locations. We obtained all E. coli and turbidity monitoring data available from existing monitoring networks for the 2000-2006 time period for the Raritan River Basin, New Jersey. Using collocated measurements, we developed a predictive model of E. coli from turbidity data. Using this model, soft data are constructed for E. coli given turbidity measurements at 739 space/time locations where only turbidity was measured. Finally, the Bayesian Maximum Entropy (BME) method of modern space/time geostatistics was used for the data integration of monitored and predicted E. coli data to produce maps showing E. coli concentration estimated daily across the river basin. The addition of soft data in conjunction with the use of river distances reduced estimation error by about 30%. Furthermore, based on these maps, up to 35% of river miles in the Raritan Basin had a probability of E coli impairment greater than 90% on the most polluted day of the study period.

A new framework for modeling urban land expansion in peri-urban area by combining multi-source datasets and data assimilation

NASA Astrophysics Data System (ADS)

Zhang, Z.; Xiao, R.; Li, X.

2015-12-01

Peri-urban area is a new type region under the impacts of both rural Industrialization and the radiation of metropolitan during rapid urbanization. Due to its complex natural and social characteristics and unique development patterns, many problems such as environmental pollution and land use waste emerged, which became an urgent issue to be addressed. Study area in this paper covers three typical peri-urban districts (Pudong, Fengxian and Jinshan), which around the Shanghai inner city. By coupling cellular automata and multi-agent system model as the basic tools, this research focus on modelling the urban land expansion and driving mechanism in peri-urban area. The big data is aslo combined with the Bayesian maximum entropy method (BME) for spatiotemporal prediction of multi-source data, which expand the dataset of urban expansion models. Data assimilation method is used to optimize the parameters of the coupling model and minimize the uncertainty of observations, improving the precision of future simulation in peri-urban area. By setting quantitative parameters, the coupling model can effectively improve the simulation of the process of urban land expansion under different policies and management schemes, in order to provide scientificimplications for new urbanization strategy. In this research, we precise the urban land expansion simulation and prediction for peri-urban area, expand the scopes and selections of data acquisition measurements and methods, develop the new applications of the data assimilation method in geographical science, provide a new idea for understanding the inherent rules of urban land expansion, and give theoretical and practical support for the peri-urban area in urban planning and decision making.

Protective effect of Bacopa monniera on methyl mercury-induced oxidative stress in cerebellum of rats.

PubMed

Sumathi, Thangarajan; Shobana, Chandrasekar; Christinal, Johnson; Anusha, Chandran

2012-08-01

Methyl mercury (MeHg) is a ubiquitous environmental pollutant leading to neurological and developmental deficits in animals and human beings. Bacopa monniera (BM) is a perennial herb and is used as a nerve tonic in Ayurveda, a traditional medicine system in India. The objective of the present study was to investigate whether Bacopa monniera extract (BME) could potentially inhibit MeHg-induced toxicity in the cerebellum of rat brain. Male Wistar rats were administered with MeHg orally at a dose of 5 mg/kg b.w. for 21 days. Experimental rats were given MeHg and also administered with BME (40 mg/kg, orally) for 21 days. After the treatment period, we observed that MeHg exposure significantly inhibited the activities of superoxide dismutase, catalase, glutathione peroxidase, and increased the glutathione reductase activity in cerebellum. It was also found that the level of thiobarbituric acid-reactive substances was increased with the concomitant decrease in the glutathione level in MeHg-induced rats. These alterations were prevented by the administration of BME. Behavioral interference in the MeHg-exposed animals was evident through a marked deficit in the motor performance in the rotarod task, which was completely recovered to control the levels by BME administration. The total mercury content in the cerebellum of MeHg-induced rats was also increased which was measured by atomic absorption spectrometry. The levels of NO(2) (-) and NO(3) (-) in the serum were found to be significantly increased in the MeHg-induced rats, whereas treatment with BME significantly decreased their levels in serum to near normal when compared to MeHg-induced rats. These findings strongly implicate that BM has potential to protect brain from oxidative damage resulting from MeHg-induced neurotoxicity in rat.

Biomedical Engineering curriculum at UAM-I: a critical review.

PubMed

Martinez Licona, Fabiola; Azpiroz-Leehan, Joaquin; Urbina Medal, E Gerardo; Cadena Mendez, Miguel

2014-01-01

The Biomedical Engineering (BME) curriculum at Universidad Autónoma Metropolitana (UAM) has undergone at least four major transformations since the founding of the BME undergraduate program in 1974. This work is a critical assessment of the curriculum from the point of view of its results as derived from an analysis of, among other resources, institutional databases on students, graduates and their academic performance. The results of the evaluation can help us define admission policies as well as reasonable limits on the maximum duration of undergraduate studies. Other results linked to the faculty composition and the social environment can be used to define a methodology for the evaluation of teaching and the implementation of mentoring and tutoring programs. Changes resulting from this evaluation may be the only way to assure and maintain leadership and recognition from the BME community.

Race, Rurality and Representation: Black and Minority Ethnic Mothers' Experiences of Their Children's Education in Rural Primary Schools in England, UK

ERIC Educational Resources Information Center

Bhopal, Kalwant

2014-01-01

There is little research that has examined the role of mothers in their children's education in the rural space of the school, particularly in relation to the experiences of Black and minority ethnic (BME) families who are newcomers to the rural space. This article attempts to redress the balance and examine how BME mothers are positioned in rural…

Effects of Climatic Variability and Change on Upland Vegetation in the Blue Mountains [Chapter 6].

Treesearch

Becky K. Kerns; David C. Powell; Sabine Mellmann-Brown; Gunnar Carnwath; John Kim

2017-01-01

The Blue Mountains ecoregion (BME) extends from the Ochoco Mountains in central Oregon to Hells Canyon of the Snake River in extreme northeastern Oregon and adjacent Idaho, and then north to the deeply carved canyons and basalt rimrock of southeastern Washington (see fig. 1.1 in chapter 1). The BME consists of a series of mountain ranges occurring in a southwest to...

Severe bone marrow edema on sacroiliac joint MRI increases the risk of low BMD in patients with axial spondyloarthritis.

PubMed

Kim, Ha Neul; Jung, Joon-Yong; Hong, Yeon Sik; Park, Sung-Hwan; Kang, Kwi Young

2016-03-02

To determine the association between inflammatory and structural lesions on sacroiliac joint (SIJ) MRI and BMD and to identify risk factors for low BMD in patients with axial spondyloarthritis (axSpA). Seventy-six patients who fulfilled the ASAS axSpA criteria were enrolled. All underwent SIJ MRI and BMD measurement at the lumbar spine, femoral neck, and total hip. Inflammatory and structural lesions on SIJ MRI were scored. Laboratory tests and assessment of radiographic and disease activity were performed at the time of MRI. The association between SIJ MRI findings and BMD was evaluated. Among the 76 patients, 14 (18%) had low BMD. Patients with low BMD showed significantly higher bone marrow edema (BME) and deep BME scores on MRI than those with normal BMD (p < 0.047 and 0.007, respectively). Inflammatory lesions on SIJ MRI correlated with BMD at the femoral neck and total hip. Multivariate analysis identified the presence of deep BME on SIJ MRI, increased CRP, and sacroiliitis on X-ray as risk factors for low BMD (OR = 5.6, 14.6, and 2.5, respectively). The presence of deep BME on SIJ MRI, increased CRP levels, and severity of sacroiliitis on X-ray were independent risk factors for low BMD.

An assessment strategy for proposals of engineering projects in the Bachelor of Biomedical Engineering Curriculum at Universidad Autónoma Metropolitana-Iztapalapa.

PubMed

Castañeda-Villa, N; Jiménez-González, A; Ortiz-Posadas, M R

2015-08-01

Since 1974, the Bachelor of Biomedical Engineering Program (BBME) is offered at Universidad Autónoma Metropolitana-Iztapalapa, in Mexico City. By design, it must be completed in four years (12 trimesters) and, in the latter three, the senior students work on a BME project, which is done by completing three modules: Project Seminar (PS), Project on BME I and Project on BME II. In the PS module, the student must find a problem of interest in the BME field and suggest a solution through the development of an Engineering Project Proposal (EPP). Currently, the module is being taught by two faculty members of the BBME, who instruct students on how to develop their EPPs and evaluate their progress by reviewing a number of EPPs during the trimester. This generates a huge workload for the module instructors, which makes it necessary to involve more faculty members trimester-to-trimester (i.e. every 12 weeks) and, therefore, to create a set of systematic guidelines that ease the evaluation process for new instructors. Hence, the purpose of this paper is to present an assessment strategy (in the form of an assessment matrix) for the PS module as well as some preliminary results after two trimesters of its implementation.

Socio-demographic diversity and unexplained variation in death rates among the most deprived parliamentary constituencies in Britain.

PubMed

Tunstall, H; Mitchell, R; Gibbs, J; Platt, S; Dorling, D

2012-06-01

There is considerable unexplained variation in death rates between deprived areas of Britain. This analysis assesses the degree of variation in socio-demographic factors among deprivation deciles and how variables associated with deaths differ among the most deprived areas. Death rates 1996-2001, Carstairs' 2001 deprivation score and indicators, population density, black and minority ethnic group (BME) and population change 1971-2001 were calculated for 641 parliamentary constituencies in Britain. Constituencies were grouped into Carstairs' deciles. We assessed standard errors of all variables by decile and the relationship between death rates and socio-demographic variables with Pearson's correlations and linear regression by decile and for all constituencies combined. Standard errors in death rates and most socio-demographic variables were greatest for the most deprived decile. Death rates among all constituencies were positively correlated with Carstairs' score and indicators, density and BME, but for the most deprived decile, there was no association with Carstairs and a negative correlation with overcrowding, density and BME. For the most deprived decile multivariate models containing population density, BME and change had substantially higher R(2). Understanding variations in death rates between deprived areas requires greater consideration of their socio-demographic diversity including their population density, ethnicity and migration.

Robust spatialization of soil water content at the scale of an agricultural field using geophysical and geostatistical methods

NASA Astrophysics Data System (ADS)

Henine, Hocine; Tournebize, Julien; Laurent, Gourdol; Christophe, Hissler; Cournede, Paul-Henry; Clement, Remi

2017-04-01

Research on the Critical Zone (CZ) is a prerequisite for undertaking issues related to ecosystemic services that human societies rely on (nutrient cycles, water supply and quality). However, while the upper part of CZ (vegetation, soil, surface water) is readily accessible, knowledge of the subsurface remains limited, due to the point-scale character of conventional direct observations. While the potential for geophysical methods to overcome this limitation is recognized, the translation of the geophysical information into physical properties or states of interest remains a challenge (e.g. the translation of soil electrical resistivity into soil water content). In this study, we propose a geostatistical framework using the Bayesian Maximum Entropy (BME) approach to assimilate geophysical and point-scale data. We especially focus on the prediction of the spatial distribution of soil water content using (1) TDR point-scale measurements of soil water content, which are considered as accurate data, and (2) soil water content data derived from electrical resistivity measurements, which are uncertain data but spatially dense. We used a synthetic dataset obtained with a vertical 2D domain to evaluate the performance of this geostatistical approach. Spatio-temporal simulations of soil water content were carried out using Hydrus-software for different scenarios: homogeneous or heterogeneous hydraulic conductivity distribution, and continuous or punctual infiltration pattern. From the simulations of soil water content, conceptual soil resistivity models were built using a forward modeling approach and point sampling of water content values, vertically ranged, were done. These two datasets are similar to field measurements of soil electrical resistivity (using electrical resistivity tomography, ERT) and soil water content (using TDR probes) obtained at the Boissy-le-Chatel site, in Orgeval catchment (East of Paris, France). We then integrated them into a specialization framework to predict the soil water content distribution and the results were compared to initial simulations (Hydrus results). We obtained more reliable water content specialization models when using the BME method. The presented approach integrates ERT and TDR measurements, and results demonstrate that its use significantly improves the spatial distribution of water content estimations. The approach will be applied to the experimental dataset collected at the Boissy le Châtel site where ERT data were collected daily during one hydrological year, using Syscal pro 48 electrodes (with a financial support of Equipex-Critex) and 10 TDR probes were used to monitor water content variation. Hourly hydrological survey (tile drainage discharge, precipitation, evapotranspiration variables and water table depth) were conducted at the same site. Data analysis and the application of geostatistical framework on the experimental dataset of 2015-2016 show satisfactory results and are reliable with the hydrological behavior of the study site.

Size and clustering of ethnic groups and rates of psychiatric admission in England.

PubMed

Venkatesan, Gayathri; Weich, Scott; McBride, Orla; Twigg, Liz; Parsons, Helen; Scott, Jan; Bhui, Kamaldeep; Keown, Patrick

2018-05-11

Aims and methodTo compare rates of admission for different types of severe mental illness between ethnic groups, and to test the hypothesis that larger and more clustered ethnic groups will have lower admission rates. This was a descriptive study of routinely collected data from the National Health Service in England. There was an eightfold difference in admission rates between ethnic groups for schizophreniform and mania admissions, and a fivefold variation in depression admissions. On average, Black and minority ethnic (BME) groups had higher rates of admission for schizophreniform and mania admissions but not for depression. This increased rate was greatest in the teenage years and early adulthood. Larger ethnic group size was associated with lower admission rates. However, greater clustering was associated with higher admission rates.Clinical implicationsOur findings support the hypothesis that larger ethnic groups have lower rates of admission. This was a between-group comparison rather than within each group. Our findings do not support the hypothesis that more clustered groups have lower rates of admission. In fact, they suggest the opposite: groups with low clustering had lower admission rates. The BME population in the UK is increasing in size and becoming less clustered. Our results suggest that both of these factors should ameliorate the overrepresentation of BME groups among psychiatric in-patients. However, this overrepresentation continues, and our results suggest a possible explanation, namely, changes in the delivery of mental health services, particularly the marked reduction in admissions for depression.Declaration of interestNone.

Ethnicity and the prostate cancer experience: a qualitative metasynthesis

PubMed Central

Matheson, Lauren; Nayoan, Johana; Glaser, Adam; Gavin, Anna; Wright, Penny; Wagland, Richard; Watson, Eila

2016-01-01

Abstract Objectives To summarize black and minority ethnic (BME) patients' and partners experiences of prostate cancer by examining the findings of existing qualitative studies. Methods We undertook a systematic metasynthesis of qualitative studies using a modified version of Noblit and Hare's “meta‐ethnography” approach, with a 2000‐2015 search of 7 databases. Results Thirteen studies of men from US and UK BME groups were included. We explored constructs with BME‐specific features. Health care provider relationships, formation of a spiritual alliance with God (which enhanced the participants' feeling of empowerment and ability to cope with the cancer), and living on for others (generally to increase cancer awareness), often connected to spiritual regrowth, were the 3 constructs most commonly reported. A magnified effect from erectile dysfunction was also common. Initially, this affected men's disclosure to others about their cancer and their sexual problems, but eventually men responded by shifting their conceptualizations of masculinity to sustain self and social identities. There was also evidence of inequality resulting from financial constraints and adversity that necessitated resilience in coping. Conclusions The prostate cancer experience of BME men and their partners is affected by a complex intersection of ethnicity with other factors. Health care services should acknowledge this. If providers recognize the men's felt masculinities, social identities, and spiritual beliefs and their shifting nature, services could be improved, with community as well as individual benefits. More studies are needed in diverse ethnic groups. PMID:27416079

An Approach to Noise Reduction in Human Skin Admittance Measurements

DTIC Science & Technology

2001-10-25

1966, 4, 439-449. [ 4] D. H. Gordon, "Triboelectric interference in the ECG", IEEE Trans., 1975, BME -22, 252-255. [ 5] J. C. Huhta and J. G...Webster, ඄-Hz interference in electrocardiography", IEEE Trans., 1973, BME -20, 91-101. [ 6] S. Grimnes, "Electrovibration, cutaneous sensation of...this period he has published two textbooks about UNIX and Shell Programming, and concentrated at computer simulation and digital signal processing

Evaluation of Commercial Automotive-Grade BME Capacitors

NASA Technical Reports Server (NTRS)

Liu, Donhang

2014-01-01

Three Ni-BaTiO3 ceramic capacitor lots with the same specification (chip size, capacitance, and rated voltage) and the same reliability level, made by three different manufacturers, were degraded using highly accelerated life stress testing (HALST) with the same temperature and applied voltage conditions. The reliability, as characterized by mean time to failure (MTTF), differed by more than one order of magnitude among the capacitor lots. A theoretical model based on the existence of depletion layers at grain boundaries and the entrapment of oxygen vacancies has been proposed to explain the MTTF difference among these BME capacitors. It is the conclusion of this model that reliability will not be improved simply by increasing the insulation resistance of a BME capacitor. Indeed, Ni-BaTiO3 ceramic capacitors with a smaller degradation rate constant K will always give rise to a longer reliability life.

Evaluation of Commercial Automotive-Grade BME Capacitors

NASA Technical Reports Server (NTRS)

Liu, Donhang

2014-01-01

Three Ni-BaTiO3 ceramic capacitor lots with the same specification (chip size, capacitance, and rated voltage) and the same reliability level, made by three different manufacturers, were degraded using highly accelerated life stress testing (HALST) with the same temperature and applied voltage conditions. The reliability, as characterized by mean time to failure (MTTF), differed by more than one order of magnitude among the capacitor lots. A theoretical model based on the existence of depletion layers at grain boundaries and the entrapment of oxygen vacancies has been proposed to explain the MTTF difference among these BME capacitors. It is the conclusion of this model that reliability will not be improved simply by increasing the insulation resistance of a BME capacitor. Indeed, Ni-BaTiO3 ceramic capacitors with a smaller degradation rate constant K will always give rise to a longer reliability life

A Thermal Runaway Failure Model for Low-Voltage BME Ceramic Capacitors with Defects

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2017-01-01

Reliability of base metal electrode (BME) multilayer ceramic capacitors (MLCCs) that until recently were used mostly in commercial applications, have been improved substantially by using new materials and processes. Currently, the inception of intrinsic wear-out failures in high quality capacitors became much greater than the mission duration in most high-reliability applications. However, in capacitors with defects degradation processes might accelerate substantially and cause infant mortality failures. In this work, a physical model that relates the presence of defects to reduction of breakdown voltages and decreasing times to failure has been suggested. The effect of the defect size has been analyzed using a thermal runaway model of failures. Adequacy of highly accelerated life testing (HALT) to predict reliability at normal operating conditions and limitations of voltage acceleration are considered. The applicability of the model to BME capacitors with cracks is discussed and validated experimentally.

From the foundation act to the corporate culture of a BME teaching institute.

PubMed

Augustyniak, Ewa; Augustyniak, Piotr

2010-01-01

This paper describes the concept and application of the organizational culture of a BME teaching institute, based on the specificity of biomedical engineering. Selected values and behavioral patterns typical for this profession were endorsed to reinforce the mutual cooperation and understanding of students, university staff and employers as partners in the educational process. Besides of building a professional pride and reputation of the teaching institute, the corporate culture is proved to be useful in imposing of the attitudes required in future career of the biomedical engineer as a partner of a medic in his efforts aimed at the wellness and safety of the patient. Five years since the foundation of the Multidisciplinary School of engineering In Biomedicine we still do not have a quantitative measure of the educational outcome quality, nevertheless the presented idea may be very useful and worth sharing with all BME educators.

The role of a creative "joint assignment" project in biomedical engineering bachelor degree education.

PubMed

Jiehui Jiang; Yuting Zhang; Mi Zhou; Xiaosong Zheng; Zhuangzhi Yan

2017-07-01

Biomedical Engineering (BME) bachelor education aims to train qualified engineers who devote themselves to addressing biological and medical problems by integrating the technological, medical and biological knowledge. Design thinking and teamwork with other disciplines are necessary for biomedical engineers. In the current biomedical engineering education system of Shanghai University (SHU), however, such design thinking and teamwork through a practical project is lacking. This paper describes a creative "joint assignment" project in Shanghai University, China, which has provided BME bachelor students a two-year practical experience to work with students from multidisciplinary departments including sociology, mechanics, computer sciences, business and art, etc. To test the feasibility of this project, a twenty-month pilot project has been carried out from May 2015 to December 2016. The results showed that this pilot project obviously enhanced competitive power of BME students in Shanghai University, both in the capabilities of design thinking and teamwork.

[Correlation analysis of bone marrow edema degree and serum inflammatory factors change with knee joint pain symptoms in patients with bone contusion around the knee joint].

PubMed

Li, Songiun; An, Rongze; Wang, Zhaojie; Kuang, Lipeng; Tan, Weiyuan; Fang, Cunxun

2014-05-01

To explore the correlation between the degree of bone marrow edema (BME) and the content change of tumor necrosis factor alpha (TNF-alpha) and matrix metalloproteinase 3 (MMP-3) and the knee pain symptoms in patients with bone contusion around the knee joint. Thirty patients (30 knees) of bone contusion around the knee joint were chosen as the trial group between October 2009 and April 2012. According to visual analogue scale (VAS), 30 patients were divided into mild group (10 cases), moderate group (10 cases), and severe group (10 cases); according to MRI morphological changes, the patients were divided into type I group (12 cases), type II group (11 cases), and type III group (7 cases). Ten patients (10 knees) with soft tissue injury of the knee were chosen as control group. No significant difference was found (P > 0.05) in gender, age, causes, side, and admission time after injury between 2 groups. The serum contents of MMP-3 and TNF-alpha were detected and statistically analysed between different degrees of pain groups and between different degrees of BME groups. Correlation was analysed between BME and inflammatory factor changes and VAS score. The MMP-3 and TNF-alpha contents in trial group [(29.580 +/- 6.870) (microg/L and (23.750 +/- 7.096) ng/L] were significantly higher than those in control group [(8.219 +/- 1.355) microg/L and (6.485 +/- 1.168) ng/L] (t = 9.686, P = 0.000; t = 7.596, P =0.000). The MMP-3 and TNF-alpha contents in patients with different degrees of pain and BME were significantly higher than those in patients of control group (P < 0.05), and significant difference was found between patients with different degrees of pain (P < 0.05), but no significant difference between patients with different degrees of BME (P > 0.05). Multiple linear regression analysis showed that TNF-alpha content was significantly correlated with VAS score (P = 0.000). Knee pain symptoms are not related to the degree of BME in patients with bone contusion around the knee joint. Inflammatory factor TNF-alpha content is the main influence factor of knee joint pain symptoms.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis

PubMed Central

Toslak, Iclal Erdem; Cekic, Bulent; Turk, Aysen; Eraslan, Ali; Parlak, A. Eda

2017-01-01

Purpose: Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP). Materials and Methods: 42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm2. Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured. Results: 36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions. Conclusion: DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play. PMID:28190854

A General Purpose Ionospheric Ray Tracing Procedure

DTIC Science & Technology

1993-08-01

hmE-bmF2) /ymF2) al(2)=chap( .5d0,2.d09 (hmPl- bmE )/ymE) a2 (2) =1. a3(2)-chap(l.dOl .4142d09 (bm~l.-hmP2) ymP2) al(3)=chap( .5d0,2.d0*(bmF2- bmE )iymE...R.H Clarke, Radiowave Propagation 1 Libraries and Information Services Australian Government Publishing Service 1 Defence Central Library - Technical

BIOCONAID System (Bionic Control of Acceleration Induced Dimming).

DTIC Science & Technology

1981-07-01

Howard, P. , "The Physiology of Positive Acceleration," Chapter 23 in A Textbook of Aviation Physiology, Edited by J. A. Gilles, Pergamon Press...of the Carotid Sinus Baroreceptor Process in a Dog ," IEEE Trans. Biomed. Engineering, BME , Vol. 22, No. 3, pp. 502-507, 1975. 16. Leverett, S. D...Electromyogram, ’ IEEE Transactions on Biomedical Engineering. Vol. BME -24, No. 5, pp. 417-424, 1977. 26. Stoll, Alice M., "Human Tolerance to Positive G as

Improving leadership skills and health outcomes.

PubMed

Mckenzie, Christine

2017-04-27

The Mary Seacole awards provide an opportunity for individuals to be recognised for their outstanding work in black and minority ethnic (BME) communities. Set up in 2004, the awards are funded by Health Education England and made in association with the Royal College of Nursing, Royal College of Midwives, Unison and Unite, with the support of NHS Employers. They are open to nurses, midwives and health visitors in England, and recipients need not come from a BME background.

Evaluation of Case Size 0603 BME Ceramic Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander A.

2015-01-01

High volumetric efficiency of commercial base metal electrode (BME) ceramic capacitors allows for a substantial reduction of weight and sizes of the parts compared to currently used military grade precious metal electrode (PME) capacitors. Insertion of BME capacitors in space applications requires a thorough analysis of their performance and reliability. In this work, six types of cases size 0603 BME capacitors from three vendors have been evaluated. Three types of multilayer ceramic capacitors (MLCCs) were designed for automotive industry and three types for general purposes. Leakage currents in the capacitors have been measured in a wide range of voltages and temperatures, and measurements of breakdown voltages (VBR) have been used to assess the proportion and severity of defects in the parts. The effect of soldering-related thermal shock stresses was evaluated by analysis of distributions of VBR for parts in 'as is' condition and after terminal solder dip testing at 350 C. Highly Accelerated Life Testing (HALT) at different temperatures was used to assess the activation energy of degradation of leakage currents and predict behavior of the parts at life test and normal operating conditions. To address issues related to rework and manual soldering, capacitors were soldered onto different substrates at different soldering conditions. The results show that contrary to a common assumption that large-size capacitors are mostly vulnerable to soldering stresses, cracking in small size capacitors does happen unless special measures are taken during assembly processes.

Ethnicity and detention: are Black and minority ethnic (BME) groups disproportionately detained under the Mental Health Act 2007?

PubMed

Gajwani, Ruchika; Parsons, Helen; Birchwood, Max; Singh, Swaran P

2016-05-01

There is substantial evidence to suggest that Black and minority ethnic (BME) patients are disproportionately detained under the Mental Health Act (MHA). We examined ethnic differences in patients assessed for detention and explored the effect of ethnicity after controlling for confounders. A prospective study of all MHA assessments conducted in 1 year (April 2009-March 2010) within Birmingham and Solihull Mental Health Foundation Trust, UK. Proportion of assessments and detentions within denominator population of service users and regional populations were calculated. Multiple regression analysis was conducted to determine which variables were associated with the outcome of MHA assessment and the role of ethnicity. Of the 1115 assessments, 709 led to detentions (63.58 %). BME ethnic groups were statistically more likely to be assessed and detained under the MHA as compared to Whites, both in the service user and the ethnic population estimates in Birmingham, UK. MHA detention was predicted by having a serious mental illness, the presence of risk, older age and living alone. Ethnicity was not associated with detention under the MHA with age, diagnosis, risk and level of social support accounted for. The BME 'disproportionality' in detention rates seems to be due to higher rates of mental illness, greater risk and poorer levels of social support rather than ethnicity per se.

The current state of basic medical education in Israel: implications for a new medical school.

PubMed

Reis, Shmuel; Borkan, Jeffrey M; Weingarten, Michael

2009-11-01

The recent government decision to establish a new medical school, the fifth in Israel, is an opportune moment to reflect on the state of Basic Medical Education (BME) in the country and globally. It provides a rare opportunity for planning an educational agenda tailored to local needs. This article moves from a description of the context of Israeli health care and the medical education system to a short overview of two existing Israeli medical schools where reforms have recently taken place. This is followed by an assessment of Israeli BME and an effort to use the insights from this assessment to inform the fifth medical school blueprint. The fifth medical school presents an opportunity for further curricular reforms and educational innovations. Reforms and innovations include: fostering self-directed professional development methods; emphasis on teaching in the community; use of appropriate educational technology; an emphasis on patient safety and simulation training; promoting the humanities in medicine; and finally the accountability to the community that the graduates will serve.

Fortification of dark chocolate with spray dried black mulberry (Morus nigra) waste extract encapsulated in chitosan-coated liposomes and bioaccessability studies.

PubMed

Gültekin-Özgüven, Mine; Karadağ, Ayşe; Duman, Şeyma; Özkal, Burak; Özçelik, Beraat

2016-06-15

Fine-disperse anionic liposomes containing black mulberry (Morus nigra) extract (BME) were prepared by high pressure homogenization at 25,000 psi. Primary liposomes were coated with cationic chitosan (0.4, w/v%) using the layer-by-layer depositing method and mixed with maltodextrin (MD) (20, w/v%) prior to spray drying. After that, spray dried liposomal powders containing BME were added to chocolates with alkalization degrees (pH 4.5, 6, 7.5) at conching temperatures of 40 °C, 60 °C, and 80 °C. The results showed that, compared to spray dried extract, chitosan coated liposomal powders provided better protection of anthocyanin content in both increased temperature and pH. In addition, encapsulation in liposomes enhanced in vitro bioaccessability of anthocyanins. Chocolate was fortified with encapsulated anthocyanins maximum 76.8% depending on conching temperature and pH. Copyright © 2016. Published by Elsevier Ltd.

Perceived causes of differential attainment in UK postgraduate medical training: a national qualitative study.

PubMed

Woolf, Katherine; Rich, Antonia; Viney, Rowena; Needleman, Sarah; Griffin, Ann

2016-11-25

Explore trainee doctors' experiences of postgraduate training and perceptions of fairness in relation to ethnicity and country of primary medical qualification. Qualitative semistructured focus group and interview study. Postgraduate training in England (London, Yorkshire and Humber, Kent Surrey and Sussex) and Wales. 137 participants (96 trainees, 41 trainers) were purposively sampled from a framework comprising: doctors from all stages of training in general practice, medicine, obstetrics and gynaecology, psychiatry, radiology, surgery or foundation, in 4 geographical areas, from white and black and minority ethnic (BME) backgrounds, who qualified in the UK and abroad. Most trainees described difficult experiences, but BME UK graduates (UKGs) and international medical graduates (IMGs) could face additional difficulties that affected their learning and performance. Relationships with senior doctors were crucial to learning but bias was perceived to make these relationships more problematic for BME UKGs and IMGs. IMGs also had to deal with cultural differences and lack of trust from seniors, often looking to IMG peers for support instead. Workplace-based assessment and recruitment were considered vulnerable to bias whereas examinations were typically considered more rigorous. In a system where success in recruitment and assessments determines where in the country you can get a job, and where work-life balance is often poor, UK BME and international graduates in our sample were more likely to face separation from family and support outside of work, and reported more stress, anxiety or burnout that hindered their learning and performance. A culture in which difficulties are a sign of weakness made seeking support and additional training stigmatising. BME UKGs and IMGs can face additional difficulties in training which may impede learning and performance. Non-stigmatising interventions should focus on trainee-trainer relationships at work and organisational changes to improve trainees' ability to seek social support outside work. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Qualitative phytochemical screening and evaluation of anti-inflammatory, analgesic and antipyretic activities of Microcos paniculata barks and fruits.

PubMed

Aziz, Md Abdullah

2015-05-01

The main objectives of this study were to qualitatively evaluate the profile of phytochemical constituents present in methanolic extract of Microcos paniculata bark (BME) and fruit (FME), as well as to evaluate their anti-inflammatory, analgesic and antipyretic activities. Phytochemical constituents of BME and FME were determined by different qualitative tests such as Molisch's test, Fehling's test, alkaloid test, frothing test, FeCl3 test, alkali test, Salkowski's test and Baljet test. The anti-inflammatory, analgesic and antipyretic activities of the extracts were evaluated through proteinase-inhibitory assay, xylene-induced ear edema test, cotton pellet-induced granuloma formation in mice, formalin test, acetic acid-induced writhing test, tail immersion test and Brewer's yeast-induced pyrexia in mice. M. paniculata extracts revealed the presence of carbohydrates, alkaloids, saponins, tannins, flavonoids and triterpenoids. All of the extracts showed significant (P<0.05, vs aspirin group) proteinase-inhibitory activity, whereas the highest effect elicited by plant extracts was exhibited by the BME (75.94% proteinase inhibition activity) with a half-maximal inhibitory concentration (IC50) of 61.31 μg/mL. Each extract at the doses of 200 and 400 mg/kg body weight showed significant (P<0.05, vs control) percentage inhibition of ear edema and granuloma formation. These extracts significantly (P<0.05, vs control) reduced the paw licking and abdominal writhing of mice. In addition, BME 400 mg/kg, and FME at 200 and 400 mg/kg showed significant (P<0.05, vs control) analgesic activities at 60 min in the tail immersion test. Again, the significant (P<0.05, vs control) post-treatment antipyretic activities were found by BME 200 and 400 mg/kg and FME 400 mg/kg respectively. Study results indicate that M. paniculata may provide a source of plant compounds with anti-inflammatory, analgesic and antipyretic activities.

Uptake and outcome of combination antiretroviral therapy in men who have sex with men according to ethnic group: the UK CHIC Study.

PubMed

2012-04-15

We investigated differences in retention in HIV care and uptake of combination antiretroviral therapy (cART) and treatment outcomes between different ethnic men who have sex with men (MSM) groups. MSM subjects with known ethnicity and ≥1 day follow-up from 1996 to 2009 in the UK Collaborative HIV Cohort Study were included. Black and minority ethnic (BME) men were categorized as: black; Indian/Pakistani/Bangladeshi; other Asian/Oriental; and other/mixed. Logistic regression was used to identify factors associated with treatment initiation within the 6 months after each CD4 count. HIV viral load, CD4 counts, discontinuation/switch of a drug in the initial cART regimen, and development of a new AIDS event/death at 6 and 12 months were also analyzed. Of 16,406 MSM, 1818 (11.0%) were BME; 892 (49.1%) black, 139 (7.6%) Indian/Pakistani/Bangladeshi, 254 (13.9%) other Asian/Oriental, 532 (29.2%) other/mixed. The proportion of MSM with no follow-up after HIV diagnosis was higher among BME than white MSM (3.4% vs. 2.2%, P = 0.002). Permanent loss to follow-up was highest in the other/mixed and lowest in Indian/Pakistani/Bangladeshi groups (P = 0.02). Six thousand three hundred thirty-eight MSM initiated first cART from January 1, 2000, to January 1, 2009. In multivariable analyses, BME MSM were 18% less likely to initiate cART than white MSM with similar CD4 counts [adjusted odds ratio 0.82 (95% confidence interval: 0.74 to 0.91), P = 0.0001]. However, once on cART, there were no differences in virological, immunological, and clinical outcomes. This study demonstrates that despite BME MSM being a "minority within a minority" for those HIV infected, there are few ethnic disparities in access to and treatment outcomes in our setting.

Perceived causes of differential attainment in UK postgraduate medical training: a national qualitative study

PubMed Central

Viney, Rowena; Needleman, Sarah; Griffin, Ann

2016-01-01

Objectives Explore trainee doctors’ experiences of postgraduate training and perceptions of fairness in relation to ethnicity and country of primary medical qualification. Design Qualitative semistructured focus group and interview study. Setting Postgraduate training in England (London, Yorkshire and Humber, Kent Surrey and Sussex) and Wales. Participants 137 participants (96 trainees, 41 trainers) were purposively sampled from a framework comprising: doctors from all stages of training in general practice, medicine, obstetrics and gynaecology, psychiatry, radiology, surgery or foundation, in 4 geographical areas, from white and black and minority ethnic (BME) backgrounds, who qualified in the UK and abroad. Results Most trainees described difficult experiences, but BME UK graduates (UKGs) and international medical graduates (IMGs) could face additional difficulties that affected their learning and performance. Relationships with senior doctors were crucial to learning but bias was perceived to make these relationships more problematic for BME UKGs and IMGs. IMGs also had to deal with cultural differences and lack of trust from seniors, often looking to IMG peers for support instead. Workplace-based assessment and recruitment were considered vulnerable to bias whereas examinations were typically considered more rigorous. In a system where success in recruitment and assessments determines where in the country you can get a job, and where work–life balance is often poor, UK BME and international graduates in our sample were more likely to face separation from family and support outside of work, and reported more stress, anxiety or burnout that hindered their learning and performance. A culture in which difficulties are a sign of weakness made seeking support and additional training stigmatising. Conclusions BME UKGs and IMGs can face additional difficulties in training which may impede learning and performance. Non-stigmatising interventions should focus on trainee–trainer relationships at work and organisational changes to improve trainees’ ability to seek social support outside work. PMID:27888178

Effect of Antioxidants (β-mercaptoethanol and Cysteamine) on Assisted Reproductive Technology In vitro.

PubMed

Nikseresht, Mohsen; Toori, Mehdi Akbartabar; Rahimi, Hamid Reza; Fallahzadeh, Ali Reza; Kahshani, Iraj Ragerdi; Hashemi, Seyedeh Fatemeh; Bahrami, Solmaz; Mahmoudi, Reza

2017-02-01

Oocyte Culture of Germinal Vesicle (GV) and its growth improves Assisted Reproductive Technology (ART) invitro and infertility. Inappropriate culture medium environment, low quality of oocytes, increase in Oxidative Stress (OS) events, Reactive Oxygen Species (ROS) and free radicals production are the main factors that result in unsuccessful Invitro Maturation (IVM) and decrease in reproduction. The present study was conducted with the aim to evaluate the effect of β-mercaptoethanol (BME) and Cysteamine (CYS) on IVM improvement, embryo fertilization and development of blastocyst of mouse immature oocyte. Oocytes were obtained from 4-6 weeks old Naval Medical Research Institute (NMRI) female mice, 48 hours after stimulation with Intraperitoneal (IP) injection of 10 IU Pregnant Mare Serum Gonadotropin (PMSG). GV oocyte with and without cumulus cells were isolated from ovaries and cultured in Tissue Culture Medium (TCM) 199 with availability of 100 μM of antioxidants (BME and CYS). After 24 hours, mature oocyte in metaphase II (MII) were fertilized with sperm in In vitro Fertilization (IVF) medium (T6) and evaluated for fetal development into blastocyst. BME and CYS could significantly (p<0.05) increase the rate of IVM and oocyte evolution, and embryo formation in medium culture. Furthermore, it is demonstrated that existence of Cumulus Oocyte Complexes (COC) significantly showed better IVM, fertilization and evolution trend as compared to oocytes without cumulus cover or Denuded Oocytes (DO), especially in TCM199 plus BME and CYS. So that the change in GV stage oocytes to MII (maturation rate), fertilization rates or 2PN formation, and two cell embryos formation or blastocyst development rate in the treatment group with addition of BME & CYS and COC was statistically significant as compared to the DO group (p-value < 0.0001). Both cellular and environmental factors could be important and involved in ART improvement.

Understanding Relationships between Health, Ethnicity, Place and the Role of Urban Green Space in Deprived Urban Communities

PubMed Central

Roe, Jenny; Aspinall, Peter A.; Ward Thompson, Catharine

2016-01-01

Very little is known about how differences in use and perceptions of urban green space impact on the general health of black and minority ethnic (BME) groups. BME groups in the UK suffer from poorer health and a wide range of environmental inequalities that include poorer access to urban green space and poorer quality of green space provision. This study used a household questionnaire (n = 523) to explore the relationship between general health and a range of individual, social and physical environmental predictors in deprived white British and BME groups living in ethnically diverse cities in England. Results from Chi-Squared Automatic Interaction Detection (CHAID) segmentation analyses identified three distinct general health segments in our sample ranging from “very good” health (people of Indian origin), to ”good” health (white British), and ”poor” health (people of African-Caribbean, Bangladeshi, Pakistani origin and other BME groups), labelled ”Mixed BME” in the analyses. Correlated Component Regression analyses explored predictors of general health for each group. Common predictors of general health across all groups were age, disability, and levels of physical activity. However, social and environmental predictors of general health-including use and perceptions of urban green space-varied among the three groups. For white British people, social characteristics of place (i.e., place belonging, levels of neighbourhood trust, loneliness) ranked most highly as predictors of general health, whilst the quality of, access to and the use of urban green space was a significant predictor of general health for the poorest health group only, i.e., in ”Mixed BME”. Results are discussed from the perspective of differences in use and perceptions of urban green space amongst ethnic groups. We conclude that health and recreation policy in the UK needs to give greater attention to the provision of local green space amongst poor BME communities since this can play an important role in helping address the health inequalities experienced by these groups. PMID:27399736

Retinoids, retinoid analogs, and lactoferrin interact and differentially affect cell viability of 2 bovine mammary cell types in vitro.

PubMed

Wang, Y; Baumrucker, C R

2010-07-01

Two bovine mammary cell types (BME-UV1 and MeBo cells) were used to evaluate the effect of natural retinoids, retinoid analogs, and bovine lactoferrin (bLf) on cell viability in vitro. Experiments with Alamar Blue showed a linear relationship between fluorescence and cell viability index. The BME-UV1 cells exhibited twice the metabolic activity but required half the doubling time of the MeBo cells. The BME-UV1 cells were very sensitive to all-trans retinoic acid (atRA) inhibition of cell viability (P<0.05) and exhibited a dose-dependent inhibition with 9-cisRA (9cRA; P<0.05). The MeBo cells exhibited some inhibition with these natural ligands (P<0.05), but they were not as sensitive. The addition of bLf had similar inhibitory effects (P<0.05) on cell viability of the 2 mammary cell types. Applications of RA receptor (RAR) agonist indicated that the stimulation of the RAR in both mammary cell types was highly effective in inhibition of cell viability (P<0.05), whereas the application of an RAR antagonist stimulated MeBo cell viability (P<0.05) and inhibited BME-UV1 cell viability (P<0.05). Finally, the use of the RAR antagonist in conjunction with bLf indicated a rescue of the bLf effect in the MeBo cells, suggesting that bLf is acting through the RAR receptor. Conversely, bLf reverted inhibition of cell viability by 9cRA in the BME-UV1 cell type (P<0.05). We conclude that RAR interaction in bovine mammary cell types regulates cell viability in vitro; we hypothesize that the natural ligands mediate regulation of bovine mammary cell viability in vivo and that bLf can either enhance or reverse the retinoid-induced inhibition of cell viability, depending on the type of bovine mammary cell studied.

Modern Space/Time Geostatistics using River Distances: Data Integration of Turbidity and E.coli Measurements to Assess Fecal Contamination Along the Raritan River in New Jersey

PubMed Central

Money, Eric S.; Carter, Gail P.; Serre, Marc L.

2009-01-01

Escherichia coli (E.coli) is a widely used indicator of fecal contamination in water bodies. External contact and subsequent ingestion of bacteria coming from fecal contamination can lead to harmful health effects. Since E.coli data are sometimes limited, the objective of this study is to use secondary information in the form of turbidity to improve the assessment of E.coli at un-monitored locations. We obtained all E.coli and turbidity monitoring data available from existing monitoring networks for the 2000 – 2006 time period for the Raritan River Basin, New Jersey. Using collocated measurements we developed a predictive model of E.coli from turbidity data. Using this model, soft data are constructed for E.coli given turbidity measurements at 739 space/time locations where only turbidity was measured. Finally, the Bayesian Maximum Entropy (BME) method of modern space/time geostatistics was used for the data integration of monitored and predicted E.coli data to produce maps showing E.coli concentration estimated daily across the river basin. The addition of soft data in conjunction with the use of river distances reduced estimation error by about 30%. Furthermore, based on these maps, up to 35% of river miles in the Raritan Basin had a probability of E.coli impairment greater than 90% on the most polluted day of the study period. PMID:19544881

Stability and Control. Volume 2. Stability and Control Flight Test Theory

DTIC Science & Technology

1974-07-01

e we have 2 mx , . mx , mx n am e + bme + ce = 0 or (am2 + bm + c)emx = 0 (1.21) mx , n Since e ? 0...1.97) (1.98) Substituting 2 mt , , mt , mt n am e + bme + ce =0 (1.99) and emt (am2 + bm + c) =0 (1.100) led us to assert that 1.98 would...derive Laplace transforms each time we use them. Extensive tables of transforms exist in most advanced mathe- matics and control system textbooks . We

Diversity training: a DVD resource showcasing BME role models.

PubMed

Shaw, Pamela

2010-12-01

Progress in encouraging and enabling more black and minority ethnic (BME) staff into positions of leadership within the NHS has been slow. This paper reports on a project to develop a DVD in order to portray positive images of BME leaders and the contributions that they make to the NHS. Filmed semi-structured interviews were conducted with 13 participants in leadership positions to explore their experiences, along with audiotaped interviews and electronic questionnaires with those who did not wish to be filmed. Sections of film were selected for inclusion in the DVD based on key themes. Participants described the positive influences, factors and barriers that had affected their careers. Self-motivation was seen as a key factor, while being able to cope with work-life balance was the biggest challenge for many of the respondents. Overall, most of the interviewees felt that they had achieved their aims and recognised that their success was due more to inner qualities than external factors.

Ethnicity and the prostate cancer experience: a qualitative metasynthesis.

PubMed

Rivas, Carol; Matheson, Lauren; Nayoan, Johana; Glaser, Adam; Gavin, Anna; Wright, Penny; Wagland, Richard; Watson, Eila

2016-10-01

To summarize black and minority ethnic (BME) patients' and partners experiences of prostate cancer by examining the findings of existing qualitative studies. We undertook a systematic metasynthesis of qualitative studies using a modified version of Noblit and Hare's "meta-ethnography" approach, with a 2000-2015 search of 7 databases. Thirteen studies of men from US and UK BME groups were included. We explored constructs with BME-specific features. Health care provider relationships, formation of a spiritual alliance with God (which enhanced the participants' feeling of empowerment and ability to cope with the cancer), and living on for others (generally to increase cancer awareness), often connected to spiritual regrowth, were the 3 constructs most commonly reported. A magnified effect from erectile dysfunction was also common. Initially, this affected men's disclosure to others about their cancer and their sexual problems, but eventually men responded by shifting their conceptualizations of masculinity to sustain self and social identities. There was also evidence of inequality resulting from financial constraints and adversity that necessitated resilience in coping. The prostate cancer experience of BME men and their partners is affected by a complex intersection of ethnicity with other factors. Health care services should acknowledge this. If providers recognize the men's felt masculinities, social identities, and spiritual beliefs and their shifting nature, services could be improved, with community as well as individual benefits. More studies are needed in diverse ethnic groups. © 2016 The Authors. Psycho-Oncology published by John Wiley & Sons Ltd.

Dual-Energy Imaging of Bone Marrow Edema on a Dedicated Multi-Source Cone-Beam CT System for the Extremities.

PubMed

Zbijewski, W; Sisniega, A; Stayman, J W; Thawait, G; Packard, N; Yorkston, J; Demehri, S; Fritz, J; Siewerdsen, J H

2015-02-21

Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI.

A spatiotemporal dengue fever early warning model accounting for nonlinear associations with meteorological factors: a Bayesian maximum entropy approach

NASA Astrophysics Data System (ADS)

Lee, Chieh-Han; Yu, Hwa-Lung; Chien, Lung-Chang

2014-05-01

Dengue fever has been identified as one of the most widespread vector-borne diseases in tropical and sub-tropical. In the last decade, dengue is an emerging infectious disease epidemic in Taiwan especially in the southern area where have annually high incidences. For the purpose of disease prevention and control, an early warning system is urgently needed. Previous studies have showed significant relationships between climate variables, in particular, rainfall and temperature, and the temporal epidemic patterns of dengue cases. However, the transmission of the dengue fever is a complex interactive process that mostly understated the composite space-time effects of dengue fever. This study proposes developing a one-week ahead warning system of dengue fever epidemics in the southern Taiwan that considered nonlinear associations between weekly dengue cases and meteorological factors across space and time. The early warning system based on an integration of distributed lag nonlinear model (DLNM) and stochastic Bayesian Maximum Entropy (BME) analysis. The study identified the most significant meteorological measures including weekly minimum temperature and maximum 24-hour rainfall with continuous 15-week lagged time to dengue cases variation under condition of uncertainty. Subsequently, the combination of nonlinear lagged effects of climate variables and space-time dependence function is implemented via a Bayesian framework to predict dengue fever occurrences in the southern Taiwan during 2012. The result shows the early warning system is useful for providing potential outbreak spatio-temporal prediction of dengue fever distribution. In conclusion, the proposed approach can provide a practical disease control tool for environmental regulators seeking more effective strategies for dengue fever prevention.

Strain improvement and metabolic flux analysis in the wild-type and a mutant Lactobacillus lactis strain for L(+)-lactic acid production.

PubMed

Bai, Dong-Mei; Zhao, Xue-Ming; Li, Xin-Gang; Xu, Shi-Min

2004-12-20

The effects of initial glucose concentration and calcium lactate concentration on the lactic acid production by the parent strain, Lactobacillus lactis BME5-18, were studied. The results of the experiments indicated that glucose and lactate repressed the cell growth and the lactic acid production by Lactobacillus lactis BME5-18. A L(+)-lactic acid overproducing strain, Lactobacillus lactis BME5-18M, was screened by mutagenizing the parent strain with ultraviolet (UV) light irradiation and selecting the high glucose and lactate calcium concentration repression resistant mutant. Starting with a concentration of 100g L(-1) glucose, the mutant produced 98.6 g L(-1) lactic acid after 60 h in flasks, 73.9% higher than that of the parent strain. The L(+)-lactic acid purity was 98.1% by weight based on the amount of total lactic acid. The culture of the parent strain could not be analyzed well by conventional metabolic flux analysis techniques, since some pyruvate were accumulated intracellularly. Therefore, a revised flux analysis method was proposed by introducing intracellular pyruvate pool. Further studies demonstrate that there is a high level of NADH oxidase activity (12.11 mmol mg(-1) min(-1)) in the parent strain. The molecular mechanisms of the strain improvement were proposed, i.e., the high level of NADH oxidase activity was eliminated and the uptake rate of glucose was increased from 82.1 C-mmol (g DW h)(-1) to 98.9 C-mmol (g DW h)(-1) by mutagenizing the parent strain with UV, and therefore the mutant strain converts mostly pyruvate to lactic acid with a higher productivity (1.76 g L(-1) h(-1)) than the parent strain (0.95 g L(-1) h(-1)).

Project-based learning with international collaboration for training biomedical engineers.

PubMed

Krishnan, Shankar

2011-01-01

Training biomedical engineers while effectively keeping up with the fast paced scientific breakthroughs and the growth in technical innovations poses arduous challenges for educators. Traditional pedagogical methods are employed for coping with the increasing demands in biomedical engineering (BME) training and continuous improvements have been attempted with some success. Project-based learning (PBL) is an academic effort that challenges students by making them carry out interdisciplinary projects aimed at accomplishing a wide range of student learning outcomes. PBL has been shown to be effective in the medical field and has been adopted by other fields including engineering. The impact of globalization in healthcare appears to be steadily increasing which necessitates the inclusion of awareness of relevant international activities in the curriculum. Numerous difficulties are encountered when the formation of a collaborative team is tried, and additional difficulties occur as the collaboration team is extended to international partners. Understanding and agreement of responsibilities becomes somewhat complex and hence the collaborative project has to be planned and executed with clear understanding by all partners and participants. A model for training BME students by adopting PBL with international collaboration is proposed. The results of previous BME project work with international collaboration fit partially into the model. There were many logistic issues and constraints; however, the collaborative projects themselves greatly enhanced the student learning outcomes. This PBL type of learning experience tends to promote long term retention of multidisciplinary material and foster high-order cognitive activities such as analysis, synthesis and evaluation. In addition to introducing the students to experiences encountered in the real-life workforce, the proposed approach enhances developing professional contracts and global networking. In conclusion, despite initial challenges, adopting project-based learning with international collaboration has strong potentials to be valuable in the training of biomedical engineering students.

Effects of chemo-mechanical polishing on CdZnTe X-ray and gamma-ray detectors

DOE PAGES

Egarievwe, Stephen E.; Hossain, Anwar; Okwechime, Ifechukwude O.; ...

2015-06-23

Here, mechanically polishing cadmium zinc telluride (CdZnTe) wafers for x-ray and gamma-ray detectors often is inadequate in removing surface defects caused by cutting them from the ingots. Fabrication-induced defects, such as surface roughness, dangling bonds, and nonstoichiometric surfaces, often are reduced through polishing and etching the surface. In our earlier studies of mechanical polishing with alumina powder, etching with hydrogen bromide in hydrogen peroxide solution, and chemomechanical polishing with bromine–methanol–ethylene glycol solution, we found that the chemomechanical polishing process produced the least surface leakage current. In this research, we focused on using two chemicals to chemomechanically polish CdZnTe wafers aftermore » mechanical polishing, viz. bromine–methanol–ethylene glycol (BME) solution, and hydrogen bromide (HBr) in a hydrogen peroxide and ethylene–glycol solution. We used x-ray photoelectron spectroscopy (XPS), current–voltage (I–V) measurements, and Am-241 spectral response measurements to characterize and compare the effects of each solution. The results show that the HBr-based solution produced lower leakage current than the BME solution. Results from using the same chemomechanical polishing solution on two samples confirmed that the surface treatment affects the measured bulk current (a combination of bulk and surface currents). XPS results indicate that the tellurium oxide to tellurium peak ratios for the mechanical polishing process were reduced significantly by chemomechanical polishing using the BME solution (78.9% for Te 3d 5/2O 2 and 76.7% for Te 3d 3/2O 2) compared with the HBr-based solution (27.6% for Te 3d 5/2O 2 and 35.8% for Te 3d 3/2O 2). Spectral response measurements showed that the 59.5-keV peak of Am-241 remained under the same channel number for all three CdZnTe samples. While the BME-based solution gave a better performance of 7.15% full-width at half-maximum (FWHM) compared with 7.59% FWHM for the HBr-based solution, the latter showed a smaller variation in performance of 0.39% FWHM over 7 days compared with 0.69% for the BME-based solution.« less

Whole-body MRI assessment of disease activity and structural damage in rheumatoid arthritis: first step towards an MRI joint count.

PubMed

Axelsen, Mette Bjørndal; Eshed, Iris; Duer-Jensen, Anne; Møller, Jakob M; Pedersen, Susanne Juhl; Østergaard, Mikkel

2014-05-01

The aim of this study was to investigate the ability of whole-body MRI (WBMRI) to visualize inflammation [synovitis, bone marrow oedema (BME) and enthesitis] and structural damage in patients with RA. The 3T WBMR images were acquired in a head-to-toe scan in 20 patients with RA and at least one swollen or tender joint. Short Tau Inversion Recovery and pre- and post-contrast T1-weighted images were evaluated for readability and the presence/absence of inflammation (synovitis, BME and enthesitis) and structural damage (erosions and fat infiltrations) in 76 peripheral joints, 30 entheseal sites and in the spine. The readability was >70% for all individual joints, except for the most peripheral joints of the hands and feet. Synovitis was most frequent in the wrist, first tarsometatarsal, first CMC joints and glenohumeral joints (67-61%); BME in the wrist, CMC, acromioclavicular and glenohumeral joints (45-35%) and erosions in the wrist, MTP and CMC joints (19-16%). Enthesitis at ≥ 1 site was registered in 16 patients. BME was frequently seen in the cervical (20%) but not the thoracic and lumbar spine, while fat infiltrations and erosions were rare. The intrareader agreement was high (85-100%) for all pathologies. The agreement between WBMRI and clinical findings was low. Peripheral and axial inflammation and structural damage at joints and entheses was frequently identified by WBMRI, and more frequently than by clinical examination. WBMRI is a promising tool for evaluation of the total inflammatory load of inflammation (an MRI joint count) and structural damage in RA patients.

Open Biomedical Engineering education in Africa.

PubMed

Ahluwalia, Arti; Atwine, Daniel; De Maria, Carmelo; Ibingira, Charles; Kipkorir, Emmauel; Kiros, Fasil; Madete, June; Mazzei, Daniele; Molyneux, Elisabeth; Moonga, Kando; Moshi, Mainen; Nzomo, Martin; Oduol, Vitalice; Okuonzi, John

2015-08-01

Despite the virtual revolution, the mainstream academic community in most countries remains largely ignorant of the potential of web-based teaching resources and of the expansion of open source software, hardware and rapid prototyping. In the context of Biomedical Engineering (BME), where human safety and wellbeing is paramount, a high level of supervision and quality control is required before open source concepts can be embraced by universities and integrated into the curriculum. In the meantime, students, more than their teachers, have become attuned to continuous streams of digital information, and teaching methods need to adapt rapidly by giving them the skills to filter meaningful information and by supporting collaboration and co-construction of knowledge using open, cloud and crowd based technology. In this paper we present our experience in bringing these concepts to university education in Africa, as a way of enabling rapid development and self-sufficiency in health care. We describe the three summer schools held in sub-Saharan Africa where both students and teachers embraced the philosophy of open BME education with enthusiasm, and discuss the advantages and disadvantages of opening education in this way in the developing and developed world.

Time-series analysis of sleep wake stage of rat EEG using time-dependent pattern entropy

NASA Astrophysics Data System (ADS)

Ishizaki, Ryuji; Shinba, Toshikazu; Mugishima, Go; Haraguchi, Hikaru; Inoue, Masayoshi

2008-05-01

We performed electroencephalography (EEG) for six male Wistar rats to clarify temporal behaviors at different levels of consciousness. Levels were identified both by conventional sleep analysis methods and by our novel entropy method. In our method, time-dependent pattern entropy is introduced, by which EEG is reduced to binary symbolic dynamics and the pattern of symbols in a sliding temporal window is considered. A high correlation was obtained between level of consciousness as measured by the conventional method and mean entropy in our entropy method. Mean entropy was maximal while awake (stage W) and decreased as sleep deepened. These results suggest that time-dependent pattern entropy may offer a promising method for future sleep research.

Can motivations for studying dentistry inform us about gender and BME differences in dental academic careers?

PubMed

Waylen, A; Barnes, O; Kenyon, P; Neville, P

2017-01-13

There are various motivators that prompt people to study dentistry but there is evidence that the salience of each varies according to gender and black and minority ethnic (BME) group. Given the current focus on inequality within the science, technology, engineering, medicine and mathematics (STEMM) academic disciplines where dentistry sits, it is important to understand the relevance of different motivators to different social groups if inequality is to be overcome. We carried out a survey of dental students from 11 out of the 18 dental schools in the UK to find out what prompted them to study dentistry. Our findings showed that most people make a personal choice to study dentistry and follow a patient-focused career while the prospect of an academic career was important for less than half of our sample. Differences according to gender and BME group were apparent but did not follow these trends. In order to continue to improve the diversity within dental academia dental schools should consider the different preferences of the workforce and work to broaden its potential.

Language, games and the role of interpreters in psychiatric diagnosis: a Wittgensteinian thought experiment.

PubMed

Thomas, P; Shah, A; Thornton, T

2009-06-01

British society is becoming increasingly culturally and linguistically diverse. This poses a major challenge to mental health services charged with the responsibility to work in ways that respect cultural and linguistic difference. In this paper we investigate the problems of interpretation in the diagnosis of depression using a thought experiment to demonstrate important features of language-games, an idea introduced by Ludwig Wittgenstein in his late work, Philosophical investigations. The thought experiment draws attention to the importance of culture and contexts in understanding the meaning of particular utterances. This has implications not only for how we understand the role of interpreters in clinical settings, and who might best be suited to function in such a role, but more generally it draws attention to the importance of involving members of black minority ethnic (BME) communities in working alongside mainstream mental health services. We conclude that the involvement of BME community development workers inside, alongside and outside statutory services can potentially improve the quality of care for people from BME communities who use these services.

The dilemma of BME research projects in developing countries: a case study.

PubMed

Zahedi, Edmond; Attar, Hamid Movahedian

2011-01-01

Researchers are faced with huge challenges when undertaking BME research projects in developing countries. Various administrative, technical, economic and even cultural barriers have to be overcome whereas the quality and quantity of the output has to be comparable with the developed world in order to make results publishable. This paper uses a real project context to highlight the major problems and the necessity of a holistic approach which would take into consideration all stakeholders interests. It is only by tackling problems such as relationship between academia-industry and administration efficiency at their root that significant progress can be achieved.

High Order Entropy-Constrained Residual VQ for Lossless Compression of Images

NASA Technical Reports Server (NTRS)

Kossentini, Faouzi; Smith, Mark J. T.; Scales, Allen

1995-01-01

High order entropy coding is a powerful technique for exploiting high order statistical dependencies. However, the exponentially high complexity associated with such a method often discourages its use. In this paper, an entropy-constrained residual vector quantization method is proposed for lossless compression of images. The method consists of first quantizing the input image using a high order entropy-constrained residual vector quantizer and then coding the residual image using a first order entropy coder. The distortion measure used in the entropy-constrained optimization is essentially the first order entropy of the residual image. Experimental results show very competitive performance.

Aiming for a shorter rheumatoid arthritis MRI protocol: can contrast-enhanced MRI replace T2 for the detection of bone marrow oedema?

PubMed

Stomp, Wouter; Krabben, Annemarie; van der Heijde, Désirée; Huizinga, Tom W J; Bloem, Johan L; van der Helm-van Mil, Annette H M; Reijnierse, Monique

2014-10-01

To determine whether T1 post-gadolinium chelate images (T1Gd) can replace T2-weighted images (T2) for evaluating bone marrow oedema (BME), thereby allowing a shorter magnetic resonance imaging (MRI) protocol in rheumatoid arthritis (RA). In 179 early arthritis patients and 43 advanced RA patients, wrist and metacarpophalangeal joints were examined on a 1.5-T extremity MRI system with a standard protocol (coronal T1, T2 fat-saturated and coronal and axial T1 fat-saturated after Gd). BME was scored according to OMERACT RAMRIS by two observers with and without T2 images available. Agreement was assessed using intraclass correlation coefficients (ICCs) for semi-quantitative scores and test characteristics with T2 images as reference. Agreement between scores based on T2 and T1Gd images was excellent ICC (0.80-0.99). At bone level, sensitivity and specificity of BME on T1Gd compared to T2 were high for both patient groups and both readers (all ≥80 %). T1Gd and T2 images are equally suitable for evaluating BME. Because contrast is usually administered to assess (teno)synovitis, a short MRI protocol of T1 and T1Gd is sufficient in RA. • Bone marrow oedema scores are equal on T2 and T1-Gd-chelate enhanced sequences. • Agreement between scores based on T2 and T1-Gd-chelate images was excellent. • Sensitivity and specificity for presence of bone marrow oedema were high. • A short protocol without T2 images suffices in rheumatoid arthritis patients.

Athletic Pubalgia in Females: Predictive Value of MRI in Outcomes of Endoscopic Surgery.

PubMed

Matikainen, Markku; Hermunen, Heikki; Paajanen, Hannu

2017-08-01

Athletic pubalgia is typically associated with male athletes participating in contact sports and less frequently with females. Endoscopic surgery may fully treat the patient with athletic pubalgia. To perform an outcomes analysis of magnetic resonance imaging (MRI) and endoscopic surgery in female patients with athletic pubalgia. Cohort study; Level of evidence, 3. Fifteen physically active female patients (mean age, 37 years) with athletic pubalgia were treated surgically via placement of total extraperitoneal endoscopic polypropylene mesh behind the injured groin area. The presence of preoperative bone marrow edema (BME) at the pubic symphysis seen on MRI was graded from 0 to 3 and correlated with pain scores after surgery. The outcome measures were pre- and postoperative pain scores and recovery to daily activity between 1 and 12 months after surgery. Results were compared with previously published scores from male athletes (n = 30). With the exception of lower body mass index, the females with (n = 8) and without (n = 7) pubic BME had similar patient characteristics to the corresponding males. Mean inguinal pain scores (0-10) before surgical treatment were greater in females than males (during exercise, 7.8 ± 1.1 vs 6.9 ± 1.1; P = .0131). One month after surgery, mean pain scores for females were still greater compared with males (2.9 ± 1.7 vs 1.3 ± 1.6; P = .0034). Compared with female athletes with normal MRI, pubic BME was related to increased mean preoperative pain scores (8.13 ± 0.99 vs 6.43 ± 1.2; P = .0122). After 1 year, surgical outcomes were excellent or good in 47% of women. Endoscopic surgery was helpful in half of the females with athletic pubalgia in this study. The presence of pubic BME may predict slightly prolonged recovery from surgery.

Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology.

PubMed

Taljanovic, Mihra S; Graham, Anna R; Benjamin, James B; Gmitro, Arthur F; Krupinski, Elizabeth A; Schwartz, Stephanie A; Hunter, Tim B; Resnick, Donald L

2008-05-01

To correlate the amount of bone marrow edema (BME) calculated by magnetic resonance imaging(MRI) with clinical findings, histopathology, and radiographic findings, in patients with advanced hip osteoarthritis(OA). The study was approved by The Institutional Human Subject Protection Committee. Coronal MRI of hips was acquired in 19 patients who underwent hip replacement. A spin echo (SE) sequence with four echoes and separate fast spin echo (FSE) proton density (PD)-weighted SE sequences of fat (F) and water (W) were acquired with water and fat suppression, respectively. T2 and water:fat ratio calculations were made for the outlined regions of interest. The calculated MRI values were correlated with the clinical, radiographic, and histopathologic findings. Analyses of variance were done on the MRI data for W/(W + F) and for T2 values (total and focal values) for the symptomatic and contralateral hips. The values were significantly higher in the study group. Statistically significant correlations were found between pain and total W/(W + F), pain and focal T2 values, and the number of microfractures and calculated BME for the focal W/(W + F) in the proximal femora. Statistically significant correlations were found between the radiographic findings and MRI values for total W/(W + F), focal W/(W + F) and focal T2 and among the radiographic findings, pain, and hip movement. On histopathology, only a small amount of BME was seen in eight proximal femora. The amount of BME in the OA hip, as measured by MRI, correlates with the severity of pain, radiographic findings, and number of microfractures.

A diameter-sensitive flow entropy method for reliability consideration in water distribution system design

NASA Astrophysics Data System (ADS)

Liu, Haixing; Savić, Dragan; Kapelan, Zoran; Zhao, Ming; Yuan, Yixing; Zhao, Hongbin

2014-07-01

Flow entropy is a measure of uniformity of pipe flows in water distribution systems. By maximizing flow entropy one can identify reliable layouts or connectivity in networks. In order to overcome the disadvantage of the common definition of flow entropy that does not consider the impact of pipe diameter on reliability, an extended definition of flow entropy, termed as diameter-sensitive flow entropy, is proposed. This new methodology is then assessed by using other reliability methods, including Monte Carlo Simulation, a pipe failure probability model, and a surrogate measure (resilience index) integrated with water demand and pipe failure uncertainty. The reliability assessment is based on a sample of WDS designs derived from an optimization process for each of the two benchmark networks. Correlation analysis is used to evaluate quantitatively the relationship between entropy and reliability. To ensure reliability, a comparative analysis between the flow entropy and the new method is conducted. The results demonstrate that the diameter-sensitive flow entropy shows consistently much stronger correlation with the three reliability measures than simple flow entropy. Therefore, the new flow entropy method can be taken as a better surrogate measure for reliability and could be potentially integrated into the optimal design problem of WDSs. Sensitivity analysis results show that the velocity parameters used in the new flow entropy has no significant impact on the relationship between diameter-sensitive flow entropy and reliability.

Constitutive expression of the AHR signaling pathway in a bovine mammary epithelial cell line and modulation by dioxin-like PCB and other AHR ligands.

PubMed

Girolami, Flavia; Spalenza, Veronica; Manzini, Livio; Carletti, Monica; Nebbia, Carlo

2015-01-05

Environmental pollutants, such as dioxin-like (DL) PCBs, benzo(a) pyrene (B[a]P), and flavonoids are aryl hydrocarbon receptor (AHR) ligands and may be excreted in dairy milk. The expression of AHR-target genes, particularly those involved in xenobiotic biotransformation, and their modulation by two DL-PCBs, B[a]P, and β-naphthoflavone was investigated in a bovine mammary epithelial cell line (BME-UV). As assessed by quantitative PCR, BME-UV cells expressed a functional AHR signaling pathway. All the AHR ligands induced a concentration-related increase in the transcription of cytochrome P450 1A1 and 1B1, known to be implicated in the bioactivation of several xenobiotics. Conversely, genes encoding for antioxidant and detoxifying enzymes, like quinone oxidoreductase or glutathione S-transferase A2, were not affected or even depressed. This study demonstrates the occurrence and the modulation by different AHR-ligands of genes involved in xenobiotic metabolism in BME-UV cells, with the potential generation of (re) active metabolites that may damage mammary tissue and/or affect animal or human health via the contaminated milk. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Reliability Model for Ni-BaTiO3-Based (BME) Ceramic Capacitors

NASA Technical Reports Server (NTRS)

Liu, Donhang

2014-01-01

The evaluation of multilayer ceramic capacitors (MLCCs) with base-metal electrodes (BMEs) for potential NASA space project applications requires an in-depth understanding of their reliability. The reliability of an MLCC is defined as the ability of the dielectric material to retain its insulating properties under stated environmental and operational conditions for a specified period of time t. In this presentation, a general mathematic expression of a reliability model for a BME MLCC is developed and discussed. The reliability model consists of three parts: (1) a statistical distribution that describes the individual variation of properties in a test group of samples (Weibull, log normal, normal, etc.), (2) an acceleration function that describes how a capacitors reliability responds to external stresses such as applied voltage and temperature (All units in the test group should follow the same acceleration function if they share the same failure mode, independent of individual units), and (3) the effect and contribution of the structural and constructional characteristics of a multilayer capacitor device, such as the number of dielectric layers N, dielectric thickness d, average grain size r, and capacitor chip size S. In general, a two-parameter Weibull statistical distribution model is used in the description of a BME capacitors reliability as a function of time. The acceleration function that relates a capacitors reliability to external stresses is dependent on the failure mode. Two failure modes have been identified in BME MLCCs: catastrophic and slow degradation. A catastrophic failure is characterized by a time-accelerating increase in leakage current that is mainly due to existing processing defects (voids, cracks, delamination, etc.), or the extrinsic defects. A slow degradation failure is characterized by a near-linear increase in leakage current against the stress time; this is caused by the electromigration of oxygen vacancies (intrinsic defects). The two identified failure modes follow different acceleration functions. Catastrophic failures follow the traditional power-law relationship to the applied voltage. Slow degradation failures fit well to an exponential law relationship to the applied electrical field. Finally, the impact of capacitor structure on the reliability of BME capacitors is discussed with respect to the number of dielectric layers in an MLCC unit, the number of BaTiO3 grains per dielectric layer, and the chip size of the capacitor device.

trans-[Pt(BCat')Me(PCy3)2]: an experimental case study of reductive elimination processes in Pt-Boryls through associative mechanisms.

PubMed

Braunschweig, Holger; Bertermann, Rüdiger; Brenner, Peter; Burzler, Michael; Dewhurst, Rian D; Radacki, Krzysztof; Seeler, Fabian

2011-10-10

A stable trans-(alkyl)(boryl) platinum complex trans-[Pt(BCat')Me(PCy(3))(2)] (Cat'=Cat-4-tBu; Cy=cyclohexyl=C(6)H(11)) was synthesised by salt metathesis reaction of trans-[Pt(BCat')Br(PCy(3))(2)] with LiMe and was fully characterised. Investigation of the reactivity of the title compound showed complete reductive elimination of Cat'BMe at 80 °C within four weeks. This process may be accelerated by the addition of a variety of alkynes, thereby leading to the formation of the corresponding η(2) -alkyne platinum complexes, of which [Pt(η(2)-MeCCMe)(PCy(3))(2)] was characterised by X-ray crystallography. Conversion of the trans-configured title compound to a cis derivative remained unsuccessful due to an instantaneous reductive elimination process during the reaction with chelating phosphines. Treatment of trans-[Pt(BCat')Me(PCy(3))(2)] with Cat(2)B(2) led to the formation of CatBMe and Cat'BMe. In the course of further investigations into this reaction, indications for two indistinguishable reaction mechanisms were found: 1) associative formation of a six-coordinate platinum centre prior to reductive elimination and 2) σ-bond metathesis of B-B and C-Pt bonds. Mechanism 1 provides a straightforward explanation for the formation of both methylboranes. Scrambling of diboranes(4) Cat(2)B(2) and Cat'(2)B(2) in the presence of [Pt(PCy(3))(2)], fully reductive elimination of CatBMe or Cat'BMe from trans-[Pt(BCat')Me(PCy(3))(2)] in the presence of sub-stoichiometric amounts of Cat(2)B(2), and evidence for the reversibility of the oxidative addition of Cat(2)B(2) to [Pt(PCy(3))(2)] all support mechanism 2, which consists of sequential equilibria reactions. Furthermore, the solid-state molecular structure of cis-[Pt(BCat)(2)(PCy(3))(2)] and cis-[Pt(BCat')(2)(PCy(3))(2)] were investigated. The remarkably short B-B separations in both bis(boryl) complexes suggest that the two boryl ligands in each case are more loosely bound to the Pt(II) centre than in related bis(boryl) species. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The performance evaluation model of mining project founded on the weight optimization entropy value method

NASA Astrophysics Data System (ADS)

Mao, Chao; Chen, Shou

2017-01-01

According to the traditional entropy value method still have low evaluation accuracy when evaluating the performance of mining projects, a performance evaluation model of mineral project founded on improved entropy is proposed. First establish a new weight assignment model founded on compatible matrix analysis of analytic hierarchy process (AHP) and entropy value method, when the compatibility matrix analysis to achieve consistency requirements, if it has differences between subjective weights and objective weights, moderately adjust both proportions, then on this basis, the fuzzy evaluation matrix for performance evaluation. The simulation experiments show that, compared with traditional entropy and compatible matrix analysis method, the proposed performance evaluation model of mining project based on improved entropy value method has higher accuracy assessment.

Controlling the Shannon Entropy of Quantum Systems

PubMed Central

Xing, Yifan; Wu, Jun

2013-01-01

This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking. PMID:23818819

Controlling the shannon entropy of quantum systems.

PubMed

Xing, Yifan; Wu, Jun

2013-01-01

This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking.

Dual-threshold segmentation using Arimoto entropy based on chaotic bee colony optimization

NASA Astrophysics Data System (ADS)

Li, Li

2018-03-01

In order to extract target from complex background more quickly and accurately, and to further improve the detection effect of defects, a method of dual-threshold segmentation using Arimoto entropy based on chaotic bee colony optimization was proposed. Firstly, the method of single-threshold selection based on Arimoto entropy was extended to dual-threshold selection in order to separate the target from the background more accurately. Then intermediate variables in formulae of Arimoto entropy dual-threshold selection was calculated by recursion to eliminate redundant computation effectively and to reduce the amount of calculation. Finally, the local search phase of artificial bee colony algorithm was improved by chaotic sequence based on tent mapping. The fast search for two optimal thresholds was achieved using the improved bee colony optimization algorithm, thus the search could be accelerated obviously. A large number of experimental results show that, compared with the existing segmentation methods such as multi-threshold segmentation method using maximum Shannon entropy, two-dimensional Shannon entropy segmentation method, two-dimensional Tsallis gray entropy segmentation method and multi-threshold segmentation method using reciprocal gray entropy, the proposed method can segment target more quickly and accurately with superior segmentation effect. It proves to be an instant and effective method for image segmentation.

The Mela Study: exploring barriers to diabetes research in black and minority ethnic groups.

PubMed

Hood, Gillian A; Chowdhury, Tahseen A; Griffiths, Christopher J; Hood, Rosie K E; Mathews, Christopher; Hitman, Graham A

2015-01-01

Black and minority ethnic (BME) groups are particularly susceptible to diabetes and its vascular complications in the United Kingdom and most western societies. To understand potential predisposition and tailor treatments accordingly, there is a real need to engage these groups in diabetes research. Despite this, BME participation in research studies continues to remain low in most countries and this may be a contributory factor to reduced health outcomes and poorer quality of life in these groups. This study explores the barriers BME groups may have towards participation in diabetes research in one area of East London, and includes local recommendations on how to improve this for the future. A questionnaire designed from previously reported exploratory work and piloted in several BME localities was distributed at the East London Bangladeshi Mela and similar cultural and religious events in London, UK. People were asked opportunistically to complete the survey themselves if they understood English, or discuss their responses with an advocate. The purpose of the questionnaire was to understand current local awareness with regards to diabetes, identify specific BME barriers and attitudes towards diabetes research by ethnicity, gender and age, and gain insight into how these barriers may be addressed. Of 1682 people surveyed (16-90 years; median age 40 years), 36.4% were South Asian, 25.9% White, and 11.1% Black and other ethnicities; 26.6% withheld their ethnicity. Over half cited language problems generally (54%) and lack of research awareness (56%) as main barriers to engaging in research. South Asian groups were more likely to cite research as too time consuming (42%) whereas Black groups were more concerned with potential drug side effects in research (39%). Participants expressed a general mistrust of research, and the need for researchers to be honest in their approach. Recommendations for increased participation in South Asian groups centred round both helping the community (61%) and improving health (55%). With regards to gender influences, females (34.6%) were significantly more likely to fear drug side effects than males (23.8%), P<0.001. Females were also significantly more likely not to participate in research due to fear of experimentation (25.8%) compared with males (18.9%) P=<0.001. Initial findings from the study demonstrate that in East London research barriers are focused on time, drug side effects, lack of awareness and language. There is a perception that research is time consuming even though the majority of those surveyed had not taken part in a research study. Further potential solutions from the survey have suggested that researchers also need to involve BME community leaders in their study strategy and indicate any individual health benefits to participation in research. Accessible studies with regards to time and advocacy provision need to be included in the design.

Can't surf, won't surf: The digital divide in mental health

PubMed Central

Ennis, Liam; Rose, Diana; Denis, Mike; Pandit, Ninjeri; Wykes, Til

2012-01-01

Background: New health information technology (HIT) increasingly plays a role in health care as technology becomes cheaper and more widespread. However, there is a danger that those who do not use or have access to technology will not benefit from HIT innovations, thus creating a “digital divide”. Aims: To assess the extent to which mental health service users have access to, skills in using and appetite for various technologies. Methods: A cross-sectional survey was used to assess technology use and access patterns of 121 people from community mental health services. Data were analysed using logistic regression. Results: Technology use and access were very similar to that of the general population with older individuals reporting less familiarity, access and confidence across a range of technologies. Black, minority and ethnic (BME) groups were more likely to access computers outside of their own homes than white individuals. Older participants experiencing psychosis indicated a desire to increase their computer use. Conclusions: The findings reported here contrast with recent evidence suggesting that those who do not engage with technology are “self-excluders”. Furthermore, BME groups may need extra support regarding provision of technology in order to engage with HIT. PMID:22712756

Financial time series analysis based on effective phase transfer entropy

NASA Astrophysics Data System (ADS)

Yang, Pengbo; Shang, Pengjian; Lin, Aijing

2017-02-01

Transfer entropy is a powerful technique which is able to quantify the impact of one dynamic system on another system. In this paper, we propose the effective phase transfer entropy method based on the transfer entropy method. We use simulated data to test the performance of this method, and the experimental results confirm that the proposed approach is capable of detecting the information transfer between the systems. We also explore the relationship between effective phase transfer entropy and some variables, such as data size, coupling strength and noise. The effective phase transfer entropy is positively correlated with the data size and the coupling strength. Even in the presence of a large amount of noise, it can detect the information transfer between systems, and it is very robust to noise. Moreover, this measure is indeed able to accurately estimate the information flow between systems compared with phase transfer entropy. In order to reflect the application of this method in practice, we apply this method to financial time series and gain new insight into the interactions between systems. It is demonstrated that the effective phase transfer entropy can be used to detect some economic fluctuations in the financial market. To summarize, the effective phase transfer entropy method is a very efficient tool to estimate the information flow between systems.

New Fault Recognition Method for Rotary Machinery Based on Information Entropy and a Probabilistic Neural Network.

PubMed

Jiang, Quansheng; Shen, Yehu; Li, Hua; Xu, Fengyu

2018-01-24

Feature recognition and fault diagnosis plays an important role in equipment safety and stable operation of rotating machinery. In order to cope with the complexity problem of the vibration signal of rotating machinery, a feature fusion model based on information entropy and probabilistic neural network is proposed in this paper. The new method first uses information entropy theory to extract three kinds of characteristics entropy in vibration signals, namely, singular spectrum entropy, power spectrum entropy, and approximate entropy. Then the feature fusion model is constructed to classify and diagnose the fault signals. The proposed approach can combine comprehensive information from different aspects and is more sensitive to the fault features. The experimental results on simulated fault signals verified better performances of our proposed approach. In real two-span rotor data, the fault detection accuracy of the new method is more than 10% higher compared with the methods using three kinds of information entropy separately. The new approach is proved to be an effective fault recognition method for rotating machinery.

Growth of the eye lens: II. Allometric studies

PubMed Central

2014-01-01

Purpose The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Methods Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated from wet and dry weights with eye volumes calculated from axial length. Results Linear allometric relationships were obtained for the comparison of ontogenic lens and bodyweight accumulation. The body mass exponent (BME) decreased with increasing animal size from around 1.0 in small rodents to 0.4 in large ungulates for both wet and dry weights. Compaction constants for the ontogenic growth ranged from 1.00 in birds and reptiles up to 1.30 in mammals. Allometric comparison of maximum lens wet and dry weights with maximum bodyweights also yielded linear plots with a BME of 0.504 for all warm blooded species except primates which had a BME of 0.25. When lens volumes were compared with eye volumes, all species yielded a scaling constant of 0.75 but the proportionality constants for primates and birds were lower. Conclusions Ontogenic lens growth is fastest, relative to body growth, in small animals and slowest in large animals. Fiber cell compaction takes place throughout life in most species, but not in birds and reptiles. Maximum adult lens size scales with eye size with the same exponent in all species, but birds and primates have smaller lenses relative to eye size than other species. Optical properties of the lens are generated through the combination of variations in the rate of growth, rate of compaction, shape and size. PMID:24715759

Fusion information entropy method of rolling bearing fault diagnosis based on n-dimensional characteristic parameter distance

NASA Astrophysics Data System (ADS)

Ai, Yan-Ting; Guan, Jiao-Yue; Fei, Cheng-Wei; Tian, Jing; Zhang, Feng-Ling

2017-05-01

To monitor rolling bearing operating status with casings in real time efficiently and accurately, a fusion method based on n-dimensional characteristic parameters distance (n-DCPD) was proposed for rolling bearing fault diagnosis with two types of signals including vibration signal and acoustic emission signals. The n-DCPD was investigated based on four information entropies (singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet space characteristic spectrum entropy and wavelet energy spectrum entropy in time-frequency domain) and the basic thought of fusion information entropy fault diagnosis method with n-DCPD was given. Through rotor simulation test rig, the vibration and acoustic emission signals of six rolling bearing faults (ball fault, inner race fault, outer race fault, inner-ball faults, inner-outer faults and normal) are collected under different operation conditions with the emphasis on the rotation speed from 800 rpm to 2000 rpm. In the light of the proposed fusion information entropy method with n-DCPD, the diagnosis of rolling bearing faults was completed. The fault diagnosis results show that the fusion entropy method holds high precision in the recognition of rolling bearing faults. The efforts of this study provide a novel and useful methodology for the fault diagnosis of an aeroengine rolling bearing.

Use of information entropy measures of sitting postural sway to quantify developmental delay in infants

PubMed Central

Deffeyes, Joan E; Harbourne, Regina T; DeJong, Stacey L; Kyvelidou, Anastasia; Stuberg, Wayne A; Stergiou, Nicholas

2009-01-01

Background By quantifying the information entropy of postural sway data, the complexity of the postural movement of different populations can be assessed, giving insight into pathologic motor control functioning. Methods In this study, developmental delay of motor control function in infants was assessed by analysis of sitting postural sway data acquired from force plate center of pressure measurements. Two types of entropy measures were used: symbolic entropy, including a new asymmetric symbolic entropy measure, and approximate entropy, a more widely used entropy measure. For each method of analysis, parameters were adjusted to optimize the separation of the results from the infants with delayed development from infants with typical development. Results The method that gave the widest separation between the populations was the asymmetric symbolic entropy method, which we developed by modification of the symbolic entropy algorithm. The approximate entropy algorithm also performed well, using parameters optimized for the infant sitting data. The infants with delayed development were found to have less complex patterns of postural sway in the medial-lateral direction, and were found to have different left-right symmetry in their postural sway, as compared to typically developing infants. Conclusion The results of this study indicate that optimization of the entropy algorithm for infant sitting postural sway data can greatly improve the ability to separate the infants with developmental delay from typically developing infants. PMID:19671183

High-Order Entropy Stable Finite Difference Schemes for Nonlinear Conservation Laws: Finite Domains

NASA Technical Reports Server (NTRS)

Fisher, Travis C.; Carpenter, Mark H.

2013-01-01

Developing stable and robust high-order finite difference schemes requires mathematical formalism and appropriate methods of analysis. In this work, nonlinear entropy stability is used to derive provably stable high-order finite difference methods with formal boundary closures for conservation laws. Particular emphasis is placed on the entropy stability of the compressible Navier-Stokes equations. A newly derived entropy stable weighted essentially non-oscillatory finite difference method is used to simulate problems with shocks and a conservative, entropy stable, narrow-stencil finite difference approach is used to approximate viscous terms.

Entropy in bimolecular simulations: A comprehensive review of atomic fluctuations-based methods.

PubMed

Kassem, Summer; Ahmed, Marawan; El-Sheikh, Salah; Barakat, Khaled H

2015-11-01

Entropy of binding constitutes a major, and in many cases a detrimental, component of the binding affinity in biomolecular interactions. While the enthalpic part of the binding free energy is easier to calculate, estimating the entropy of binding is further more complicated. A precise evaluation of entropy requires a comprehensive exploration of the complete phase space of the interacting entities. As this task is extremely hard to accomplish in the context of conventional molecular simulations, calculating entropy has involved many approximations. Most of these golden standard methods focused on developing a reliable estimation of the conformational part of the entropy. Here, we review these methods with a particular emphasis on the different techniques that extract entropy from atomic fluctuations. The theoretical formalisms behind each method is explained highlighting its strengths as well as its limitations, followed by a description of a number of case studies for each method. We hope that this brief, yet comprehensive, review provides a useful tool to understand these methods and realize the practical issues that may arise in such calculations. Copyright © 2015 Elsevier Inc. All rights reserved.

Low Streamflow Forcasting using Minimum Relative Entropy

NASA Astrophysics Data System (ADS)

Cui, H.; Singh, V. P.

2013-12-01

Minimum relative entropy spectral analysis is derived in this study, and applied to forecast streamflow time series. Proposed method extends the autocorrelation in the manner that the relative entropy of underlying process is minimized so that time series data can be forecasted. Different prior estimation, such as uniform, exponential and Gaussian assumption, is taken to estimate the spectral density depending on the autocorrelation structure. Seasonal and nonseasonal low streamflow series obtained from Colorado River (Texas) under draught condition is successfully forecasted using proposed method. Minimum relative entropy determines spectral of low streamflow series with higher resolution than conventional method. Forecasted streamflow is compared to the prediction using Burg's maximum entropy spectral analysis (MESA) and Configurational entropy. The advantage and disadvantage of each method in forecasting low streamflow is discussed.

Quantifying selection and diversity in viruses by entropy methods, with application to the haemagglutinin of H3N2 influenza

PubMed Central

Pan, Keyao; Deem, Michael W.

2011-01-01

Many viruses evolve rapidly. For example, haemagglutinin (HA) of the H3N2 influenza A virus evolves to escape antibody binding. This evolution of the H3N2 virus means that people who have previously been exposed to an influenza strain may be infected by a newly emerged virus. In this paper, we use Shannon entropy and relative entropy to measure the diversity and selection pressure by an antibody in each amino acid site of H3 HA between the 1992–1993 season and the 2009–2010 season. Shannon entropy and relative entropy are two independent state variables that we use to characterize H3N2 evolution. The entropy method estimates future H3N2 evolution and migration using currently available H3 HA sequences. First, we show that the rate of evolution increases with the virus diversity in the current season. The Shannon entropy of the sequence in the current season predicts relative entropy between sequences in the current season and those in the next season. Second, a global migration pattern of H3N2 is assembled by comparing the relative entropy flows of sequences sampled in China, Japan, the USA and Europe. We verify this entropy method by describing two aspects of historical H3N2 evolution. First, we identify 54 amino acid sites in HA that have evolved in the past to evade the immune system. Second, the entropy method shows that epitopes A and B on the top of HA evolve most vigorously to escape antibody binding. Our work provides a novel entropy-based method to predict and quantify future H3N2 evolution and to describe the evolutionary history of H3N2. PMID:21543352

Bacopa monniera (L.) wettst inhibits type II collagen-induced arthritis in rats.

PubMed

Viji, V; Kavitha, S K; Helen, A

2010-09-01

Bacopa monniera (L.) Wettst is an Ayurvedic herb with antirheumatic potential. This study investigated the therapeutic efficacy of Bacopa monniera in treating rheumatoid arthritis using a type II collagen-induced arthritis rat model. Arthritis was induced in male Wistar rats by immunization with bovine type II collagen in complete Freund's adjuvant. Bacopa monniera extract (BME) was administered after the development of arthritis from day 14 onwards. The total duration of experiment was 60 days. Paw swelling, arthritic index, inflammatory mediators such as cyclooxygenase, lipoxygenase, myeloperoxidase and serum anti-collagen IgG and IgM levels were analysed in control and experimental rats. Arthritic induction significantly increased paw edema and other classical signs of arthritis coupled to upregulation of inflammatory mediators such as cyclooxygenase, lipoxygenase, neutrophil infiltration and increased anti-collagen IgM and IgG levels in serum. BME significantly inhibited the footpad swelling and arthritic symptoms. BME was effective in inhibiting cyclooxygenase and lipoxygenase activities in arthritic rats. Decreased neutrophil infiltration was evident from decreased myeloperoxidase activity and histopathological data where an improvement in joint architecture was also observed. Serum anti-collagen IgM and IgG levels were consistently decreased. Thus the study demonstrates the potential antiarthritic effect of Bacopa monniera for treating arthritis which might confer its antirheumatic activity. Copyright 2010 John Wiley & Sons, Ltd.

Hand, foot and mouth disease: spatiotemporal transmission and climate.

PubMed

Wang, Jin-feng; Guo, Yan-Sha; Christakos, George; Yang, Wei-Zhong; Liao, Yi-Lan; Li, Zhong-Jie; Li, Xiao-Zhou; Lai, Sheng-Jie; Chen, Hong-Yan

2011-04-05

The Hand-Foot-Mouth Disease (HFMD) is the most common infectious disease in China, its total incidence being around 500,000~1,000,000 cases per year. The composite space-time disease variation is the result of underlining attribute mechanisms that could provide clues about the physiologic and demographic determinants of disease transmission and also guide the appropriate allocation of medical resources to control the disease. HFMD cases were aggregated into 1456 counties and during a period of 11 months. Suspected climate attributes to HFMD were recorded monthly at 674 stations throughout the country and subsequently interpolated within 1456 × 11 cells across space-time (same as the number of HFMD cases) using the Bayesian Maximum Entropy (BME) method while taking into consideration the relevant uncertainty sources. The dimensionalities of the two datasets together with the integrated dataset combining the two previous ones are very high when the topologies of the space-time relationships between cells are taken into account. Using a self-organizing map (SOM) algorithm the dataset dimensionality was effectively reduced into 2 dimensions, while the spatiotemporal attribute structure was maintained. 16 types of spatiotemporal HFMD transmission were identified, and 3-4 high spatial incidence clusters of the HFMD types were found throughout China, which are basically within the scope of the monthly climate (precipitation) types. HFMD propagates in a composite space-time domain rather than showing a purely spatial and purely temporal variation. There is a clear relationship between HFMD occurrence and climate. HFMD cases are geographically clustered and closely linked to the monthly precipitation types of the region. The occurrence of the former depends on the later.

Inhibition of lipoxygenases and cyclooxygenase-2 enzymes by extracts isolated from Bacopa monniera (L.) Wettst.

PubMed

Viji, V; Helen, A

2008-07-23

Bacopa monniera Linn is described in the Ayurvedic Materia Medica, as a therapeutically useful herb for the treatment of inflammation. In the current study, we investigated the anti-inflammatory activity of methanolic extract of Bacopa monniera (BME). For some experiments EtOAc and bacoside fractions were prepared from BME. The effect of these extracts in modulating key mediators of inflammation was evaluated. Carrageenan-induced rat paw edema, rat mononuclear cells and human whole blood assay were employed as in vivo and in vitro models. In carrageenan-induced rat paw edema, BME brought about 82% edema inhibition at a dose of 100mg/kg i.p. when compared to indomethacin (INDO) (3mg/kg) that showed 70% edema inhibition. BME also significantly inhibited 5-lipoxygenase (5-LOX), 15-LOX and cyclooxygenase-2 (COX-2) activities in rat monocytes in vivo. Among the fractions tested in vitro, EtOAc fraction possessed significant 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with IC(50) value of 30 microg/ml compared to butylated hydroxyl toluene (IC(50) = 13 microg/ml). This fraction also exerted significant hydroxyl radical scavenging activity with IC(50) value of 25 microg/ml in comparison with quercetin (IC(50) = 5 microg/ml). Inhibitory effects of EtOAc and bacoside fractions on LOX and COX activities in Ca-A23187 stimulated rat mononuclear cells were also assessed. 5-LOX IC(50) values were 25 microg/ml for EtOAc, 68 microg/ml for bacosides and 2 microg/ml for nordihydroguaiaretic acid (NDGA) where as COX-2 IC(50) values were 1.32 microg/ml for EtOAc, 1.19 microg/ml for bacoside fraction and 0.23 microg/ml for indomethacin. EtOAc and bacoside fractions also brought about significant decrease in TNF-alpha release ex vivo. Bacopa monniera possesses anti-inflammatory activity through inhibition of COX and LOX and downregulation of TNF-alpha.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis.

PubMed

Toslak, Iclal Erdem; Cekic, Bulent; Turk, Aysen; Eraslan, Ali; Parlak, A Eda

2017-10-10

Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP). 42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm 2 . Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured. 36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions. DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play.

Organisational perspectives on addressing differential attainment in postgraduate medical education: a qualitative study in the UK

PubMed Central

Viney, Rowena; Jayaweera, Hirosha; Griffin, Ann

2018-01-01

Objectives To explore how representatives from organisations with responsibility for doctors in training perceive risks to the educational progression of UK medical graduates from black and minority ethnic groups (BME UKGs), and graduates of non-UK medical schools (international medical graduates (IMGs)). To identify the barriers to and facilitators of change. Design Qualitative semistructured individual and group interview study. Setting Postgraduate medical education in the UK. Participants Individuals with roles in examinations and/or curriculum design from UK medical Royal Colleges. Employees of NHS Employers. Results Representatives from 11 medical Royal Colleges (n=29) and NHS Employers (n=2) took part (55% medically qualified, 61% male, 71% white British/Irish, 23% Asian/Asian British, 6% missing ethnicity). Risks were perceived as significant, although more so for IMGs than for BME UKGs. Participants based significance ratings on evidence obtained largely through personal experience. A lack of evidence led to downgrading of significance. Participants were pessimistic about effecting change, two main barriers being sensitivities around race and the isolation of interventions. Participants felt that organisations should acknowledge problems, but felt concerned about being transparent without a solution; and talking about race with trainees was felt to be difficult. Participants mentioned 63 schemes aiming to address differential attainment, but these were typically local or specialty-specific, were not aimed at BME UKGs and were largely unevaluated. Participants felt that national change was needed, but only felt empowered to effect change locally or within their specialty. Conclusions Representatives from organisations responsible for training doctors perceived the risks faced by BME UKGs and IMGs as significant but difficult to change. Strategies to help organisations address these risks include: increased openness to discussing race (including ethnic differences in attainment among UKGs); better sharing of information and resources nationally to empower organisations to effect change locally and within specialties; and evaluation of evidence-based interventions. PMID:29525774

Magnetic resonance imaging of the sacroiliac joints in the early detection of spondyloarthritis: no added value of gadolinium compared with short tau inversion recovery sequence.

PubMed

de Hooge, Manouk; van den Berg, Rosaline; Navarro-Compán, Victoria; van Gaalen, Floris; van der Heijde, Désirée; Huizinga, Tom; Reijnierse, Monique

2013-07-01

To investigate the additional value of T1 fat-saturated after gadolinium (T1/Gd) compared with T1 and short tau inversion recovery (STIR) sequence in detecting active lesions of the SI joints typical of axial SpA (axSpA) in a prospective cohort study, the SpondyloArthritis Caught Early (SPACE) cohort, and to assess its influence on final MRI diagnosis of the SI joint (MRI-SIJ) based on the Assessment of Spondyloarthritis International Society (ASAS) definition of active sacroiliitis. Patients in the SPACE cohort received baseline and 3-month follow-up MRI-SIJ with coronal oblique T1, STIR and T1/Gd sequences. Bone marrow oedema (BME), capsulitis/enthesitis and synovitis and active sacroiliitis according to the ASAS definition were evaluated by three blinded readers. A total of 127 patients received an MRI-SIJ at baseline and 67 patients also received an MRI-SIJ at 3 months follow-up since the Gd protocol was added some months after the start of the SPACE project. Twenty-five of the 127 patients (19.7%) with a baseline MRI-SIJ and 14 of 67 patients (20.6%) with a follow-up MRI-SIJ presented BME on the STIR sequence sufficient to fulfill the ASAS definition for a positive MRI-SIJ. In eight patients, additional synovitis and/or capsulitis/enthesitis was observed; however, no additional BME was visualized on T1/Gd. One patient, without clinical diagnosis of axSpA, showed synovitis as an isolated finding. Synovitis and capsulitis/enthesitis are detectable with the administration of Gd. However, they are always observed in the presence of BME. Therefore T1 and STIR sequence alone are sufficient in the MRI assessment that, among others, is used for diagnosing patients with early axSpA.

Influence of weaning timing advice and associated weaning behaviours in a survey of black and minority ethnic groups in the UK.

PubMed

Moore, Amanda P; Nanthagopan, Kristina; Hammond, Grace; Milligan, Peter; Goff, Louise M

2014-09-01

To assess understanding of the Department of Health weaning guidelines and weaning influences in a self-selected sample of black and minority ethnic (BME) parents, residing in London. A face-to-face, questionnaire-facilitated survey among Black African, Black Caribbean and South Asian parents. An opportunistic sample of parents was recruited from Sure Start centres, churches and play groups across key London boroughs. Three hundred and forty-nine interviews were included; 107 Black African, fifty-four Black Caribbean, 120 South Asian and sixty-four of Black mixed-race ethnicity. Fifty-two per cent of Black and 66 % of South Asian parents had accurate understanding of the guidelines. Inaccurate knowledge of the guidelines was associated with weaning before 17 weeks (P < 0·001); 36 % of Black Africans and 31 % of Black Caribbeans were weaned before 4 months compared with 16 % of South Asians. All BME groups were most influenced by weaning information from the previous generations of mothers in their families, which was associated with earlier weaning (21·5 (SD 6·5) v. 24·1 (SD 4·2) weeks; F(2,328) = 5·79, P = 0·003), and less so by professional infant feeding advice, which was associated with a later weaning age (23·7 (SD 5·1) v. 20·7 (SD 5·7) weeks; F(1,344) = 34·7, P < 0·001). Lack of awareness of the Department of Health weaning guidelines is common among these BME populations, whose weaning behaviour is strongly influenced by informal advice. Further research is necessary to elucidate the influences on weaning in these populations and to facilitate the development of infant feeding support which is salient for BME groups in the UK.

On determining absolute entropy without quantum theory or the third law of thermodynamics

NASA Astrophysics Data System (ADS)

Steane, Andrew M.

2016-04-01

We employ classical thermodynamics to gain information about absolute entropy, without recourse to statistical methods, quantum mechanics or the third law of thermodynamics. The Gibbs-Duhem equation yields various simple methods to determine the absolute entropy of a fluid. We also study the entropy of an ideal gas and the ionization of a plasma in thermal equilibrium. A single measurement of the degree of ionization can be used to determine an unknown constant in the entropy equation, and thus determine the absolute entropy of a gas. It follows from all these examples that the value of entropy at absolute zero temperature does not need to be assigned by postulate, but can be deduced empirically.

Stepwise inference of likely dynamic flux distributions from metabolic time series data.

PubMed

Faraji, Mojdeh; Voit, Eberhard O

2017-07-15

Most metabolic pathways contain more reactions than metabolites and therefore have a wide stoichiometric matrix that corresponds to infinitely many possible flux distributions that are perfectly compatible with the dynamics of the metabolites in a given dataset. This under-determinedness poses a challenge for the quantitative characterization of flux distributions from time series data and thus for the design of adequate, predictive models. Here we propose a method that reduces the degrees of freedom in a stepwise manner and leads to a dynamic flux distribution that is, in a statistical sense, likely to be close to the true distribution. We applied the proposed method to the lignin biosynthesis pathway in switchgrass. The system consists of 16 metabolites and 23 enzymatic reactions. It has seven degrees of freedom and therefore admits a large space of dynamic flux distributions that all fit a set of metabolic time series data equally well. The proposed method reduces this space in a systematic and biologically reasonable manner and converges to a likely dynamic flux distribution in just a few iterations. The estimated solution and the true flux distribution, which is known in this case, show excellent agreement and thereby lend support to the method. The computational model was implemented in MATLAB (version R2014a, The MathWorks, Natick, MA). The source code is available at https://github.gatech.edu/VoitLab/Stepwise-Inference-of-Likely-Dynamic-Flux-Distributions and www.bst.bme.gatech.edu/research.php . mojdeh@gatech.edu or eberhard.voit@bme.gatech.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Application of an improved minimum entropy deconvolution method for railway rolling element bearing fault diagnosis

NASA Astrophysics Data System (ADS)

Cheng, Yao; Zhou, Ning; Zhang, Weihua; Wang, Zhiwei

2018-07-01

Minimum entropy deconvolution is a widely-used tool in machinery fault diagnosis, because it enhances the impulse component of the signal. The filter coefficients that greatly influence the performance of the minimum entropy deconvolution are calculated by an iterative procedure. This paper proposes an improved deconvolution method for the fault detection of rolling element bearings. The proposed method solves the filter coefficients by the standard particle swarm optimization algorithm, assisted by a generalized spherical coordinate transformation. When optimizing the filters performance for enhancing the impulses in fault diagnosis (namely, faulty rolling element bearings), the proposed method outperformed the classical minimum entropy deconvolution method. The proposed method was validated in simulation and experimental signals from railway bearings. In both simulation and experimental studies, the proposed method delivered better deconvolution performance than the classical minimum entropy deconvolution method, especially in the case of low signal-to-noise ratio.

In Vivo potassium-39 NMR spectra by the burg maximum-entropy method

NASA Astrophysics Data System (ADS)

Uchiyama, Takanori; Minamitani, Haruyuki

The Burg maximum-entropy method was applied to estimate 39K NMR spectra of mung bean root tips. The maximum-entropy spectra have as good a linearity between peak areas and potassium concentrations as those obtained by fast Fourier transform and give a better estimation of intracellular potassium concentrations. Therefore potassium uptake and loss processes of mung bean root tips are shown to be more clearly traced by the maximum-entropy method.

Nonadditive entropy maximization is inconsistent with Bayesian updating.

PubMed

Pressé, Steve

2014-11-01

The maximum entropy method-used to infer probabilistic models from data-is a special case of Bayes's model inference prescription which, in turn, is grounded in basic propositional logic. By contrast to the maximum entropy method, the compatibility of nonadditive entropy maximization with Bayes's model inference prescription has never been established. Here we demonstrate that nonadditive entropy maximization is incompatible with Bayesian updating and discuss the immediate implications of this finding. We focus our attention on special cases as illustrations.

Comparing Postural Stability Entropy Analyses to Differentiate Fallers and Non-Fallers

PubMed Central

Fino, Peter C.; Mojdehi, Ahmad R.; Adjerid, Khaled; Habibi, Mohammad; Lockhart, Thurmon E.; Ross, Shane D.

2015-01-01

The health and financial cost of falls has spurred research to differentiate the characteristics of fallers and non-fallers. Postural stability has received much of the attention with recent studies exploring various measures of entropy. This study compared the discriminatory ability of several entropy methods at differentiating two paradigms in the center-of-pressure (COP) of elderly individuals: 1.) eyes open (EO) versus eyes closed (EC) and 2.) fallers (F) versus non-fallers (NF). Methods were compared using the area under the curve (AUC) of the receiver-operating characteristic (ROC) curves developed from logistic regression models. Overall, multiscale entropy (MSE) and composite multiscale entropy (CompMSE) performed the best with AUCs of 0.71 for EO/EC and 0.77 for F/NF. When methods were combined together to maximize the AUC, the entropy classifier had an AUC of for 0.91 the F/NF comparison. These results suggest researchers and clinicians attempting to create clinical tests to identify fallers should consider a combination of every entropy method when creating a classifying test. Additionally, MSE and CompMSE classifiers using polar coordinate data outperformed rectangular coordinate data, encouraging more research into the most appropriate time series for postural stability entropy analysis. PMID:26464267

Comparing Postural Stability Entropy Analyses to Differentiate Fallers and Non-fallers.

PubMed

Fino, Peter C; Mojdehi, Ahmad R; Adjerid, Khaled; Habibi, Mohammad; Lockhart, Thurmon E; Ross, Shane D

2016-05-01

The health and financial cost of falls has spurred research to differentiate the characteristics of fallers and non-fallers. Postural stability has received much of the attention with recent studies exploring various measures of entropy. This study compared the discriminatory ability of several entropy methods at differentiating two paradigms in the center-of-pressure of elderly individuals: (1) eyes open (EO) vs. eyes closed (EC) and (2) fallers (F) vs. non-fallers (NF). Methods were compared using the area under the curve (AUC) of the receiver-operating characteristic curves developed from logistic regression models. Overall, multiscale entropy (MSE) and composite multiscale entropy (CompMSE) performed the best with AUCs of 0.71 for EO/EC and 0.77 for F/NF. When methods were combined together to maximize the AUC, the entropy classifier had an AUC of for 0.91 the F/NF comparison. These results suggest researchers and clinicians attempting to create clinical tests to identify fallers should consider a combination of every entropy method when creating a classifying test. Additionally, MSE and CompMSE classifiers using polar coordinate data outperformed rectangular coordinate data, encouraging more research into the most appropriate time series for postural stability entropy analysis.

[Evaluation of a simplified index (spectral entropy) about sleep state of electrocardiogram recorded by a simplified polygraph, MemCalc-Makin2].

PubMed

Ohisa, Noriko; Ogawa, Hiromasa; Murayama, Nobuki; Yoshida, Katsumi

2010-02-01

Polysomnography (PSG) is the gold standard for the diagnosis of sleep apnea hypopnea syndrome (SAHS), but it takes time to analyze the PSG and PSG cannot be performed repeatedly because of efforts and costs. Therefore, simplified sleep respiratory disorder indices in which are reflected the PSG results are needed. The Memcalc method, which is a combination of the maximum entropy method for spectral analysis and the non-linear least squares method for fitting analysis (Makin2, Suwa Trust, Tokyo, Japan) has recently been developed. Spectral entropy which is derived by the Memcalc method might be useful to expressing the trend of time-series behavior. Spectral entropy of ECG which is calculated with the Memcalc method was evaluated by comparing to the PSG results. Obstructive SAS patients (n = 79) and control volanteer (n = 7) ECG was recorded using MemCalc-Makin2 (GMS) with PSG recording using Alice IV (Respironics) from 20:00 to 6:00. Spectral entropy of ECG, which was calculated every 2 seconds using the Memcalc method, was compared to sleep stages which were analyzed manually from PSG recordings. Spectral entropy value (-0.473 vs. -0.418, p < 0.05) were significantly increased in the OSAHS compared to the control. For the entropy cutoff level of -0.423, sensitivity and specificity for OSAHS were 86.1% and 71.4%, respectively, resulting in a receiver operating characteristic with an area under the curve of 0.837. The absolute value of entropy had inverse correlation with stage 3. Spectral entropy, which was calculated with Memcalc method, might be a possible index evaluating the quality of sleep.

Entropy method of measuring and evaluating periodicity of quasi-periodic trajectories

NASA Astrophysics Data System (ADS)

Ni, Yanshuo; Turitsyn, Konstantin; Baoyin, Hexi; Junfeng, Li

2018-06-01

This paper presents a method for measuring the periodicity of quasi-periodic trajectories by applying discrete Fourier transform (DFT) to the trajectories and analyzing the frequency domain within the concept of entropy. Having introduced the concept of entropy, analytical derivation and numerical results indicate that entropies increase as a logarithmic function of time. Periodic trajectories typically have higher entropies, and trajectories with higher entropies mean the periodicities of the motions are stronger. Theoretical differences between two trajectories expressed as summations of trigonometric functions are also derived analytically. Trajectories in the Henon-Heiles system and the circular restricted three-body problem (CRTBP) are analyzed with the indicator entropy and compared with orthogonal fast Lyapunov indicator (OFLI). The results show that entropy is a better tool for discriminating periodicity in quasiperiodic trajectories than OFLI and can detect periodicity while excluding the spirals that are judged as periodic cases by OFLI. Finally, trajectories in the vicinity of 243 Ida and 6489 Golevka are considered as examples, and the numerical results verify these conclusions. Some trajectories near asteroids look irregular, but their higher entropy values as analyzed by this method serve as evidence of frequency regularity in three directions. Moreover, these results indicate that applying DFT to the trajectories in the vicinity of irregular small bodies and calculating their entropy in the frequency domain provides a useful quantitative analysis method for evaluating orderliness in the periodicity of quasi-periodic trajectories within a given time interval.

Entropy Stable Spectral Collocation Schemes for the Navier-Stokes Equations: Discontinuous Interfaces

NASA Technical Reports Server (NTRS)

Carpenter, Mark H.; Fisher, Travis C.; Nielsen, Eric J.; Frankel, Steven H.

2013-01-01

Nonlinear entropy stability and a summation-by-parts framework are used to derive provably stable, polynomial-based spectral collocation methods of arbitrary order. The new methods are closely related to discontinuous Galerkin spectral collocation methods commonly known as DGFEM, but exhibit a more general entropy stability property. Although the new schemes are applicable to a broad class of linear and nonlinear conservation laws, emphasis herein is placed on the entropy stability of the compressible Navier-Stokes equations.

Fault detection of the connection of lithium-ion power batteries based on entropy for electric vehicles

NASA Astrophysics Data System (ADS)

Yao, Lei; Wang, Zhenpo; Ma, Jun

2015-10-01

This paper proposes a method of fault detection of the connection of Lithium-Ion batteries based on entropy for electric vehicle. In electric vehicle operation process, some factors, such as road conditions, driving habits, vehicle performance, always affect batteries by vibration, which easily cause loosing or virtual connection between batteries. Through the simulation of the battery charging and discharging experiment under vibration environment, the data of voltage fluctuation can be obtained. Meanwhile, an optimal filtering method is adopted using discrete cosine filter method to analyze the characteristics of system noise, based on the voltage set when batteries are working under different vibration frequency. Experimental data processed by filtering is analyzed based on local Shannon entropy, ensemble Shannon entropy and sample entropy. And the best way to find a method of fault detection of the connection of lithium-ion batteries based on entropy is presented for electric vehicle. The experimental data shows that ensemble Shannon entropy can predict the accurate time and the location of battery connection failure in real time. Besides electric-vehicle industry, this method can also be used in other areas in complex vibration environment.

Driver fatigue detection through multiple entropy fusion analysis in an EEG-based system.

PubMed

Min, Jianliang; Wang, Ping; Hu, Jianfeng

2017-01-01

Driver fatigue is an important contributor to road accidents, and fatigue detection has major implications for transportation safety. The aim of this research is to analyze the multiple entropy fusion method and evaluate several channel regions to effectively detect a driver's fatigue state based on electroencephalogram (EEG) records. First, we fused multiple entropies, i.e., spectral entropy, approximate entropy, sample entropy and fuzzy entropy, as features compared with autoregressive (AR) modeling by four classifiers. Second, we captured four significant channel regions according to weight-based electrodes via a simplified channel selection method. Finally, the evaluation model for detecting driver fatigue was established with four classifiers based on the EEG data from four channel regions. Twelve healthy subjects performed continuous simulated driving for 1-2 hours with EEG monitoring on a static simulator. The leave-one-out cross-validation approach obtained an accuracy of 98.3%, a sensitivity of 98.3% and a specificity of 98.2%. The experimental results verified the effectiveness of the proposed method, indicating that the multiple entropy fusion features are significant factors for inferring the fatigue state of a driver.

Attenuation of cytotoxicity induced by tBHP in H9C2 cells by Bacopa monniera and Bacoside A.

PubMed

T, Mohan Manu; Anand, T; Khanum, Farhath

2018-06-01

Cardiovascular diseases are one of the major global health issues leading to morbidity and mortality across the world. In the present study Bacopa monniera and its major bioactive component, Bacoside A (Bac-A) was used to evaluate its cytoprotective property in H9C2 cardiomyocytes against tBHP (150 μM) induced ROS-mediated oxidative stress and apoptosis. Our results implicate that pre-treatment with hydroalcoholic extract of Bacopa monniera (BME) and Bac-A (125 μg/ml and 6 μg/ml respectively) significantly restored oxidative stress by scavenging the free radicals and also elevated phase II antioxidant defensive enzymes such as (SOD, CAT, GR, GPx and GSH). Membrane integrity was estimated by MMP and LDH assays and found 89 and 72% of the protective effect. Further immunoblotting studies confirmed anti-apoptotic effects by regulating protein expression like Bcl2 was up-regulated to 99 and 85% and Bax was down-regulated to 122 and 181%, iNOS by 154.38 and 183.45% compared to tBHP (277.48%) by BME and Bac-A. BME and Bac-A exerts cytoprotective efficacy by attenuation of ROS generated through oxidative stress by an increase in the concentration of antioxidant enzymes and sustain membrane integrity which leads to restoring the damage caused by tBHP. Copyright © 2018 Elsevier B.V. All rights reserved.

Biomedical signal and image processing.

PubMed

Cerutti, Sergio; Baselli, Giuseppe; Bianchi, Anna; Caiani, Enrico; Contini, Davide; Cubeddu, Rinaldo; Dercole, Fabio; Rienzo, Luca; Liberati, Diego; Mainardi, Luca; Ravazzani, Paolo; Rinaldi, Sergio; Signorini, Maria; Torricelli, Alessandro

2011-01-01

Generally, physiological modeling and biomedical signal processing constitute two important paradigms of biomedical engineering (BME): their fundamental concepts are taught starting from undergraduate studies and are more completely dealt with in the last years of graduate curricula, as well as in Ph.D. courses. Traditionally, these two cultural aspects were separated, with the first one more oriented to physiological issues and how to model them and the second one more dedicated to the development of processing tools or algorithms to enhance useful information from clinical data. A practical consequence was that those who did models did not do signal processing and vice versa. However, in recent years,the need for closer integration between signal processing and modeling of the relevant biological systems emerged very clearly [1], [2]. This is not only true for training purposes(i.e., to properly prepare the new professional members of BME) but also for the development of newly conceived research projects in which the integration between biomedical signal and image processing (BSIP) and modeling plays a crucial role. Just to give simple examples, topics such as brain–computer machine or interfaces,neuroengineering, nonlinear dynamical analysis of the cardiovascular (CV) system,integration of sensory-motor characteristics aimed at the building of advanced prostheses and rehabilitation tools, and wearable devices for vital sign monitoring and others do require an intelligent fusion of modeling and signal processing competences that are certainly peculiar of our discipline of BME.

Critical assessment and outlook for the 50 biomedical engineering undergraduate programs in Mexico.

PubMed

Azpiroz-Leehan, Joaquín; Martínez Licona, Fabiola; Urbina Medal, E Gerardo; Cadena Méndez, Miguel; Sacristán Rock, Emilio

2015-01-01

Biomedical Engineering (BME) has been taught in Mexico at the undergraduate level for over forty years. The rationale for the introduction of this profession was to help manage and maintain the growing technological infrastructure in the health care system during the seventies. Owing to this, it is not surprising that early versions of the BME curricula were oriented towards clinical engineering and medical instrumentation. In the last decade the number of programs has grown from three in the seventies and eighties to fifty at present. This work is the result of the analysis of the BME programs in all the institutions that offer this degree in Mexico. Three main issues were studied: the curricula, the sub-disciplines that were emphasized in the programs and the job market. Results have shown a striking resemblance in most of the programs, which are mostly dedicated to teaching aspects of medical instrumentation and clinical engineering. These results reflect an agreement with the requirements of the job market, but since most job offerings are for low-paying positions in sales, service and hospital maintenance, we question the wisdom of stressing these sub-specialties at research universities, where faculties and research labs offer a wide variety of options. An analysis of work at these centers shows that most of the results are publications, so the need to emphasize translational research and partnerships with industry are suggested.

Nonparametric entropy estimation using kernel densities.

PubMed

Lake, Douglas E

2009-01-01

The entropy of experimental data from the biological and medical sciences provides additional information over summary statistics. Calculating entropy involves estimates of probability density functions, which can be effectively accomplished using kernel density methods. Kernel density estimation has been widely studied and a univariate implementation is readily available in MATLAB. The traditional definition of Shannon entropy is part of a larger family of statistics, called Renyi entropy, which are useful in applications that require a measure of the Gaussianity of data. Of particular note is the quadratic entropy which is related to the Friedman-Tukey (FT) index, a widely used measure in the statistical community. One application where quadratic entropy is very useful is the detection of abnormal cardiac rhythms, such as atrial fibrillation (AF). Asymptotic and exact small-sample results for optimal bandwidth and kernel selection to estimate the FT index are presented and lead to improved methods for entropy estimation.

Gradient Dynamics and Entropy Production Maximization

NASA Astrophysics Data System (ADS)

Janečka, Adam; Pavelka, Michal

2018-01-01

We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.

Generalized sample entropy analysis for traffic signals based on similarity measure

NASA Astrophysics Data System (ADS)

Shang, Du; Xu, Mengjia; Shang, Pengjian

2017-05-01

Sample entropy is a prevailing method used to quantify the complexity of a time series. In this paper a modified method of generalized sample entropy and surrogate data analysis is proposed as a new measure to assess the complexity of a complex dynamical system such as traffic signals. The method based on similarity distance presents a different way of signals patterns match showing distinct behaviors of complexity. Simulations are conducted over synthetic data and traffic signals for providing the comparative study, which is provided to show the power of the new method. Compared with previous sample entropy and surrogate data analysis, the new method has two main advantages. The first one is that it overcomes the limitation about the relationship between the dimension parameter and the length of series. The second one is that the modified sample entropy functions can be used to quantitatively distinguish time series from different complex systems by the similar measure.

A climate-based spatiotemporal prediction for dengue fever epidemics: a case study in southern Taiwan

NASA Astrophysics Data System (ADS)

Yu, H.-L.; Yang, S.-J.; Lin, Y.-C.

2012-04-01

Dengue Fever (DF) has been identified by the World Health organization (WHO) as one of the most serious vector-borne infectious diseases in tropical and sub-tropical areas. DF has been one of the most important epidemics in Taiwan which occur annually especially in southern Taiwan during summer and autumn. Most DF studies have focused mainly on temporal DF patterns and its close association with climatic covariates, whereas few studies have investigated the spatial DF patterns (spatial dependence and clustering) and composite space-time effects of the DF epidemics. The present study proposes a spatio-temporal DF prediction approach based on stochastic Bayesian Maximum Entropy (BME) analysis. Core and site-specific knowledge bases are considered, including climate and health datasets under conditions of uncertainty, space-time dependence functions, and a Poisson regression model of climatic variables contributing to DF occurrences in southern Taiwan during 2007, when the highest number of DF cases was recorded in the history of Taiwan epidemics (over 2000). The obtained results show that the DF outbreaks in the study area are highly influenced by climatic conditions. Furthermore, the analysis can provide the required "one-week-ahead" outbreak warnings based on spatio-temporal predictions of DF distributions. Therefore, the proposed analysis can provide the Taiwan Disease Control Agency with a valuable tool to timely identify, control, and even efficiently prevent DF spreading across space-time.

Bubble Entropy: An Entropy Almost Free of Parameters.

PubMed

Manis, George; Aktaruzzaman, Md; Sassi, Roberto

2017-11-01

Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors. Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors.

Driver fatigue detection through multiple entropy fusion analysis in an EEG-based system

PubMed Central

Min, Jianliang; Wang, Ping

2017-01-01

Driver fatigue is an important contributor to road accidents, and fatigue detection has major implications for transportation safety. The aim of this research is to analyze the multiple entropy fusion method and evaluate several channel regions to effectively detect a driver's fatigue state based on electroencephalogram (EEG) records. First, we fused multiple entropies, i.e., spectral entropy, approximate entropy, sample entropy and fuzzy entropy, as features compared with autoregressive (AR) modeling by four classifiers. Second, we captured four significant channel regions according to weight-based electrodes via a simplified channel selection method. Finally, the evaluation model for detecting driver fatigue was established with four classifiers based on the EEG data from four channel regions. Twelve healthy subjects performed continuous simulated driving for 1–2 hours with EEG monitoring on a static simulator. The leave-one-out cross-validation approach obtained an accuracy of 98.3%, a sensitivity of 98.3% and a specificity of 98.2%. The experimental results verified the effectiveness of the proposed method, indicating that the multiple entropy fusion features are significant factors for inferring the fatigue state of a driver. PMID:29220351

Computational Methods for Configurational Entropy Using Internal and Cartesian Coordinates.

PubMed

Hikiri, Simon; Yoshidome, Takashi; Ikeguchi, Mitsunori

2016-12-13

The configurational entropy of solute molecules is a crucially important quantity to study various biophysical processes. Consequently, it is necessary to establish an efficient quantitative computational method to calculate configurational entropy as accurately as possible. In the present paper, we investigate the quantitative performance of the quasi-harmonic and related computational methods, including widely used methods implemented in popular molecular dynamics (MD) software packages, compared with the Clausius method, which is capable of accurately computing the change of the configurational entropy upon temperature change. Notably, we focused on the choice of the coordinate systems (i.e., internal or Cartesian coordinates). The Boltzmann-quasi-harmonic (BQH) method using internal coordinates outperformed all the six methods examined here. The introduction of improper torsions in the BQH method improves its performance, and anharmonicity of proper torsions in proteins is identified to be the origin of the superior performance of the BQH method. In contrast, widely used methods implemented in MD packages show rather poor performance. In addition, the enhanced sampling of replica-exchange MD simulations was found to be efficient for the convergent behavior of entropy calculations. Also in folding/unfolding transitions of a small protein, Chignolin, the BQH method was reasonably accurate. However, the independent term without the correlation term in the BQH method was most accurate for the folding entropy among the methods considered in this study, because the QH approximation of the correlation term in the BQH method was no longer valid for the divergent unfolded structures.

How to Calculate Renyi Entropy from Heart Rate Variability, and Why it Matters for Detecting Cardiac Autonomic Neuropathy.

PubMed

Cornforth, David J; Tarvainen, Mika P; Jelinek, Herbert F

2014-01-01

Cardiac autonomic neuropathy (CAN) is a disease that involves nerve damage leading to an abnormal control of heart rate. An open question is to what extent this condition is detectable from heart rate variability (HRV), which provides information only on successive intervals between heart beats, yet is non-invasive and easy to obtain from a three-lead ECG recording. A variety of measures may be extracted from HRV, including time domain, frequency domain, and more complex non-linear measures. Among the latter, Renyi entropy has been proposed as a suitable measure that can be used to discriminate CAN from controls. However, all entropy methods require estimation of probabilities, and there are a number of ways in which this estimation can be made. In this work, we calculate Renyi entropy using several variations of the histogram method and a density method based on sequences of RR intervals. In all, we calculate Renyi entropy using nine methods and compare their effectiveness in separating the different classes of participants. We found that the histogram method using single RR intervals yields an entropy measure that is either incapable of discriminating CAN from controls, or that it provides little information that could not be gained from the SD of the RR intervals. In contrast, probabilities calculated using a density method based on sequences of RR intervals yield an entropy measure that provides good separation between groups of participants and provides information not available from the SD. The main contribution of this work is that different approaches to calculating probability may affect the success of detecting disease. Our results bring new clarity to the methods used to calculate the Renyi entropy in general, and in particular, to the successful detection of CAN.

How to Calculate Renyi Entropy from Heart Rate Variability, and Why it Matters for Detecting Cardiac Autonomic Neuropathy

PubMed Central

Cornforth, David J.;  Tarvainen, Mika P.; Jelinek, Herbert F.

2014-01-01

Cardiac autonomic neuropathy (CAN) is a disease that involves nerve damage leading to an abnormal control of heart rate. An open question is to what extent this condition is detectable from heart rate variability (HRV), which provides information only on successive intervals between heart beats, yet is non-invasive and easy to obtain from a three-lead ECG recording. A variety of measures may be extracted from HRV, including time domain, frequency domain, and more complex non-linear measures. Among the latter, Renyi entropy has been proposed as a suitable measure that can be used to discriminate CAN from controls. However, all entropy methods require estimation of probabilities, and there are a number of ways in which this estimation can be made. In this work, we calculate Renyi entropy using several variations of the histogram method and a density method based on sequences of RR intervals. In all, we calculate Renyi entropy using nine methods and compare their effectiveness in separating the different classes of participants. We found that the histogram method using single RR intervals yields an entropy measure that is either incapable of discriminating CAN from controls, or that it provides little information that could not be gained from the SD of the RR intervals. In contrast, probabilities calculated using a density method based on sequences of RR intervals yield an entropy measure that provides good separation between groups of participants and provides information not available from the SD. The main contribution of this work is that different approaches to calculating probability may affect the success of detecting disease. Our results bring new clarity to the methods used to calculate the Renyi entropy in general, and in particular, to the successful detection of CAN. PMID:25250311

Application of a Real-Time, Calculable Limiting Form of the Renyi Entropy for Molecular Imaging of Tumors

PubMed Central

Marsh, J. N.; Wallace, K. D.; McCarthy, J. E.; Wickerhauser, M. V.; Maurizi, B. N.; Lanza, G. M.; Wickline, S. A.; Hughes, M. S.

2011-01-01

Previously, we reported new methods for ultrasound signal characterization using entropy, Hf; a generalized entropy, the Renyi entropy, If(r); and a limiting form of Renyi entropy suitable for real-time calculation, If,∞. All of these quantities demonstrated significantly more sensitivity to subtle changes in scattering architecture than energy-based methods in certain settings. In this study, the real-time calculable limit of the Renyi entropy, If,∞, is applied for the imaging of angiogenic murine neovasculature in a breast cancer xenograft using a targeted contrast agent. It is shown that this approach may be used to detect reliably the accumulation of targeted nanoparticles at five minutes post-injection in this in vivo model. PMID:20679020

Organisational perspectives on addressing differential attainment in postgraduate medical education: a qualitative study in the UK.

PubMed

Woolf, Katherine; Viney, Rowena; Rich, Antonia; Jayaweera, Hirosha; Griffin, Ann

2018-03-09

To explore how representatives from organisations with responsibility for doctors in training perceive risks to the educational progression of UK medical graduates from black and minority ethnic groups (BME UKGs), and graduates of non-UK medical schools (international medical graduates (IMGs)). To identify the barriers to and facilitators of change. Qualitative semistructured individual and group interview study. Postgraduate medical education in the UK. Individuals with roles in examinations and/or curriculum design from UK medical Royal Colleges. Employees of NHS Employers. Representatives from 11 medical Royal Colleges (n=29) and NHS Employers (n=2) took part (55% medically qualified, 61% male, 71% white British/Irish, 23% Asian/Asian British, 6% missing ethnicity). Risks were perceived as significant, although more so for IMGs than for BME UKGs. Participants based significance ratings on evidence obtained largely through personal experience. A lack of evidence led to downgrading of significance. Participants were pessimistic about effecting change, two main barriers being sensitivities around race and the isolation of interventions. Participants felt that organisations should acknowledge problems, but felt concerned about being transparent without a solution; and talking about race with trainees was felt to be difficult. Participants mentioned 63 schemes aiming to address differential attainment, but these were typically local or specialty-specific, were not aimed at BME UKGs and were largely unevaluated. Participants felt that national change was needed, but only felt empowered to effect change locally or within their specialty. Representatives from organisations responsible for training doctors perceived the risks faced by BME UKGs and IMGs as significant but difficult to change. Strategies to help organisations address these risks include: increased openness to discussing race (including ethnic differences in attainment among UKGs); better sharing of information and resources nationally to empower organisations to effect change locally and within specialties; and evaluation of evidence-based interventions. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Improvement of medical content in the curriculum of biomedical engineering based on assessment of students outcomes.

PubMed

Abdulhay, Enas; Khnouf, Ruba; Haddad, Shireen; Al-Bashir, Areen

2017-08-04

Improvement of medical content in Biomedical Engineering curricula based on a qualitative assessment process or on a comparison with another high-standard program has been approached by a number of studies. However, the quantitative assessment tools have not been emphasized. The quantitative assessment tools can be more accurate and robust in cases of challenging multidisciplinary fields like that of Biomedical Engineering which includes biomedicine elements mixed with technology aspects. The major limitations of the previous research are the high dependence on surveys or pure qualitative approaches as well as the absence of strong focus on medical outcomes without implicit confusion with the technical ones. The proposed work presents the development and evaluation of an accurate/robust quantitative approach to the improvement of the medical content in the challenging multidisciplinary BME curriculum. The work presents quantitative assessment tools and subsequent improvement of curriculum medical content applied, as example for explanation, to the ABET (Accreditation Board for Engineering and Technology, USA) accredited biomedical engineering BME department at Jordan University of Science and Technology. The quantitative results of assessment of curriculum/course, capstone, exit exam, course assessment by student (CAS) as well as of surveys filled by alumni, seniors, employers and training supervisors were, first, mapped to the expected students' outcomes related to the medical field (SOsM). The collected data were then analyzed and discussed to find curriculum weakness points by tracking shortcomings in every outcome degree of achievement. Finally, actions were taken to fill in the gaps of the curriculum. Actions were also mapped to the students' medical outcomes (SOsM). Weighted averages of obtained quantitative values, mapped to SOsM, indicated accurately the achievement levels of all outcomes as well as the necessary improvements to be performed in curriculum. Mapping the improvements to SOsM also helps in the assessment of the following cycle. The suggested assessment tools can be generalized and extended to any other BME department. Robust improvement of medical content in BME curriculum can subsequently be achieved.

Body mass index and extent of MRI-detected inflammation: opposite effects in rheumatoid arthritis versus other arthritides and asymptomatic persons.

PubMed

Mangnus, Lukas; Nieuwenhuis, Wouter P; van Steenbergen, Hanna W; Huizinga, Tom W J; Reijnierse, Monique; van der Helm-van Mil, Annette H M

2016-10-22

In the population a high body mass index (BMI) has been associated with slightly increased inflammatory markers. Within rheumatoid arthritis (RA), however, a high BMI has been associated with less radiographic progression; this phenomenon is unexplained. We hypothesized that the phenomenon is caused by an inverse relationship between BMI and inflammation in hand and foot joints with RA. To explore this hypothesis, local inflammation was measured using magnetic resonance imaging (MRI) in early arthritis patients presenting with RA or other arthritides and in asymptomatic volunteers. A total of 195 RA patients, 159 patients with other inflammatory arthritides included in the Leiden Early Arthritis Clinic, and 193 asymptomatic volunteers underwent a unilateral contrast-enhanced 1.5 T MRI scan of metacarpophalangeal, wrist, and metatarsophalangeal joints. Each MRI scan was scored by two readers on synovitis, bone marrow edema (BME), and tenosynovitis; the sum yielded the total MRI inflammation score. Linear regression on log-transformed MRI data was used. A higher BMI was associated with higher MRI inflammation scores in arthritides other than RA (β = 1.082, p < 0.001) and in asymptomatic volunteers (β = 1.029, p = 0.040), whereas it was associated with lower MRI inflammation scores in RA (β = 0.97, p = 0.005). Evaluating the different types of inflammation, a higher BMI was associated with higher synovitis, BME, and tenosynovitis scores in arthritides other than RA (respectively β = 1.084, p < 0.001, β = 1.021, p = 0.24, and β = 1.054, p = 0.003), but with lower synovitis and BME scores in RA (respectively β = 0.98, p = 0.047 and β = 0.95, p = 0.002). Increased BMI is correlated with less severe MRI-detected synovitis and BME in RA. This might explain the paradox in RA where obesity correlates with less severe radiographic progression.

Music viewed by its entropy content: A novel window for comparative analysis.

PubMed

Febres, Gerardo; Jaffe, Klaus

2017-01-01

Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a) a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b) a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c) the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the '2nd Order Entropy'. Applying these methods to a variety of musical pieces showed how the space of 'symbolic specific diversity-entropy' and that of '2nd order entropy' captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning.

Rényi continuous entropy of DNA sequences.

PubMed

Vinga, Susana; Almeida, Jonas S

2004-12-07

Entropy measures of DNA sequences estimate their randomness or, inversely, their repeatability. L-block Shannon discrete entropy accounts for the empirical distribution of all length-L words and has convergence problems for finite sequences. A new entropy measure that extends Shannon's formalism is proposed. Renyi's quadratic entropy calculated with Parzen window density estimation method applied to CGR/USM continuous maps of DNA sequences constitute a novel technique to evaluate sequence global randomness without some of the former method drawbacks. The asymptotic behaviour of this new measure was analytically deduced and the calculation of entropies for several synthetic and experimental biological sequences was performed. The results obtained were compared with the distributions of the null model of randomness obtained by simulation. The biological sequences have shown a different p-value according to the kernel resolution of Parzen's method, which might indicate an unknown level of organization of their patterns. This new technique can be very useful in the study of DNA sequence complexity and provide additional tools for DNA entropy estimation. The main MATLAB applications developed and additional material are available at the webpage . Specialized functions can be obtained from the authors.

Performance Analysis of Entropy Methods on K Means in Clustering Process

NASA Astrophysics Data System (ADS)

Dicky Syahputra Lubis, Mhd.; Mawengkang, Herman; Suwilo, Saib

2017-12-01

K Means is a non-hierarchical data clustering method that attempts to partition existing data into one or more clusters / groups. This method partitions the data into clusters / groups so that data that have the same characteristics are grouped into the same cluster and data that have different characteristics are grouped into other groups.The purpose of this data clustering is to minimize the objective function set in the clustering process, which generally attempts to minimize variation within a cluster and maximize the variation between clusters. However, the main disadvantage of this method is that the number k is often not known before. Furthermore, a randomly chosen starting point may cause two points to approach the distance to be determined as two centroids. Therefore, for the determination of the starting point in K Means used entropy method where this method is a method that can be used to determine a weight and take a decision from a set of alternatives. Entropy is able to investigate the harmony in discrimination among a multitude of data sets. Using Entropy criteria with the highest value variations will get the highest weight. Given this entropy method can help K Means work process in determining the starting point which is usually determined at random. Thus the process of clustering on K Means can be more quickly known by helping the entropy method where the iteration process is faster than the K Means Standard process. Where the postoperative patient dataset of the UCI Repository Machine Learning used and using only 12 data as an example of its calculations is obtained by entropy method only with 2 times iteration can get the desired end result.

Exploring stability of entropy analysis for signal with different trends

NASA Astrophysics Data System (ADS)

Zhang, Yin; Li, Jin; Wang, Jun

2017-03-01

Considering the effects of environment disturbances and instrument systems, the actual detecting signals always are carrying different trends, which result in that it is difficult to accurately catch signals complexity. So choosing steady and effective analysis methods is very important. In this paper, we applied entropy measures-the base-scale entropy and approximate entropy to analyze signal complexity, and studied the effect of trends on the ideal signal and the heart rate variability (HRV) signals, that is, linear, periodic, and power-law trends which are likely to occur in actual signals. The results show that approximate entropy is unsteady when we embed different trends into the signals, so it is not suitable to analyze signal with trends. However, the base-scale entropy has preferable stability and accuracy for signal with different trends. So the base-scale entropy is an effective method to analyze the actual signals.

Reply to "Comment on 'Quantum Kaniadakis entropy under projective measurement' ".

PubMed

Ourabah, Kamel; Tribeche, Mouloud

2016-08-01

We rely on our proof of the nondecreasing character of quantum Kaniadakis entropy under projective measurement [Phys. Rev. E 92, 032114 (2015)PLEEE81539-375510.1103/PhysRevE.92.032114], and we put it into perspective with the results of Bosyk et al. [Quantum Inf Process 15, 3393 (2016)10.1007/s11128-016-1329-5]. Our method, adopted for the proof that Kaniadakis entropy does not decrease under a projective measurement, is based on Jensen's inequalities, while the method proposed by the authors of the Comment represents another alternative and clearly correct method to prove the same thing. Furthermore, we clarify that our interest in Kaniadakis entropy is due to the fact that this entropy has a transparent physical significance, emerging within the special relativity.

Salient target detection based on pseudo-Wigner-Ville distribution and Rényi entropy.

PubMed

Xu, Yuannan; Zhao, Yuan; Jin, Chenfei; Qu, Zengfeng; Liu, Liping; Sun, Xiudong

2010-02-15

We present what we believe to be a novel method based on pseudo-Wigner-Ville distribution (PWVD) and Rényi entropy for salient targets detection. In the foundation of studying the statistical property of Rényi entropy via PWVD, the residual entropy-based saliency map of an input image can be obtained. From the saliency map, target detection is completed by the simple and convenient threshold segmentation. Experimental results demonstrate the proposed method can detect targets effectively in complex ground scenes.

Consistent maximum entropy representations of pipe flow networks

NASA Astrophysics Data System (ADS)

Waldrip, Steven H.; Niven, Robert K.; Abel, Markus; Schlegel, Michael

2017-06-01

The maximum entropy method is used to predict flows on water distribution networks. This analysis extends the water distribution network formulation of Waldrip et al. (2016) Journal of Hydraulic Engineering (ASCE), by the use of a continuous relative entropy defined on a reduced parameter set. This reduction in the parameters that the entropy is defined over ensures consistency between different representations of the same network. The performance of the proposed reduced parameter method is demonstrated with a one-loop network case study.

A critical evaluation of the UK SunSmart campaign and its relevance to Black and minority ethnic communities.

PubMed

Oyebanjo, Evelyn; Bushell, Fiona

2014-05-01

Skin cancer is the most common cancer in the United Kingdom and is rising to epidemic proportions. While the majority of skin cancers are treatable, malignant melanoma kills over 2,000 people in the United Kingdom each year, with all skin cancers killing a total of more than 2,500 people annually. SunSmart, the United Kingdom's major skin cancer public health initiative, was implemented to raise awareness about sun exposure and to promote sun safety behaviours. However, it has failed to curb the incidence and mortality rates. Furthermore, while Australia has the highest skin cancer incidence rates globally, the mortality rates are lower than those in the United Kingdom. There has also been a growing amount of evidence demonstrating ethnic disparities in skin cancer survival rates. Even though incidence rates of skin cancer among Black and minority ethnic (BME) groups are significantly lower, it is often diagnosed late, resulting in higher mortality rates. This, coupled with climate change and the proportion of BME groups expected to rise in the United Kingdom from 8% to 20% by 2051, raises public health concerns. This article aims to critically analyse the UK SunSmart campaign's success in addressing skin cancer in the population and in particular its relevance to BME communities. It also compares this approach with the Australian campaign. This article demonstrates that Australia's campaign has been more successful than the United Kingdom's due to their more comprehensive application of health promotion and public health principles.

Cartilage and bone damage in rheumatoid arthritis

PubMed Central

Maśliński, Włodzimierz; Prochorec-Sobieszek, Monika; Nieciecki, Michał; Sudoł-Szopińska, Iwona

2018-01-01

Rheumatoid arthritis (RA), which is a chronic inflammatory disease with a multifactorial aetiology, leads to partial or permanent disability in the majority of patients. It is characterised by persistent synovitis and formation of pannus, i.e. invasive synovial tissue, which ultimately leads to destruction of the cartilage, subchondral bone, and soft tissues of the affected joint. Moreover, inflammatory infiltrates in the subchondral bone, which can lead to inflammatory cysts and later erosions, play an important role in the pathogenesis of RA. These inflammatory infiltrates can be seen in magnetic resonance imaging (MRI) as bone marrow oedema (BME). BME is observed in 68–75% of patients in early stages of RA and is considered a precursor of rapid disease progression. The clinical significance of synovitis and bone marrow oedema as precursors of erosions is well established in daily practice, and synovitis, BME, cysts, hyaline cartilage defects and bone erosions can be detected by ultrasonography (US) and MRI. A less explored subject is the inflammatory and destructive potential of intra- and extra-articular fat tissue, which can also be evaluated in US and MRI. Finally, according to certain hypotheses, hyaline cartilage damage may trigger synovitis and lead to irreversible joint damage, and MRI may be used for preclinical detection of cartilage biochemical abnormalities. This review discusses the pathomechanisms that lead to articular cartilage and bone damage in RA, including erosion precursors such as synovitis and osteitis and panniculitis, as well as the role of imaging techniques employed to detect early cartilage damage and bone erosions. PMID:29853727

Frequency of inflammatory-like MR imaging findings in asymptomatic fingers of healthy volunteers.

PubMed

Agten, Christoph A; Rosskopf, Andrea B; Jonczy, Maciej; Brunner, Florian; Pfirrmann, Christian W A; Buck, Florian M

2018-02-01

To describe the frequency of inflammatory-like findings on MR imaging in asymptomatic volunteers and compare them with patients with known rheumatoid arthritis and psoriatic arthritis. MR images of fingers in 42 asymptomatic volunteers and 33 patients with rheumatoid/psoriatic arthritis were analyzed. The Outcome Measures in Rheumatology Clinical Trials (OMERACT) Rheumatoid/Psoriatic Arthritis MRI Scoring System (RAMRIS/PsAMRIS) and tenosynovitis scoring system were used to assess: bone marrow edema (BME), erosions, tendon sheath fluid/tenosynovitis, joint effusion, and soft-tissue edema. Findings and scores were compared between volunteers and patients. Inter-reader agreement was calculated (intraclass correlation coefficients, ICC). In volunteers, tendon sheath fluid was very common in at least one location (42/42 volunteers for reader 1, 34/42 volunteers for reader 2). BME, erosions, joint effusion, and soft-tissue edema were absent (except one BME in the 3rd proximal phalanx for reader 1). Tendon sheath fluid scores in volunteers and tenosynovitis scores in patients were high (reader 1, 7.17 and 5.39; reader 2, 2.31 and 5.45). Overall, inter-reader agreement was substantial (ICC = 0.696-0.844), except for tendon sheath fluid (ICC = 0.258). Fluid in the finger flexor tendon sheaths may be a normal finding and without gadolinium administration should not be interpreted as tenosynovitis. Bone marrow edema, erosions, joint effusion, and soft-tissue edema in the fingers most likely reflect pathology if present.

Maximum entropy method applied to deblurring images on a MasPar MP-1 computer

NASA Technical Reports Server (NTRS)

Bonavito, N. L.; Dorband, John; Busse, Tim

1991-01-01

A statistical inference method based on the principle of maximum entropy is developed for the purpose of enhancing and restoring satellite images. The proposed maximum entropy image restoration method is shown to overcome the difficulties associated with image restoration and provide the smoothest and most appropriate solution consistent with the measured data. An implementation of the method on the MP-1 computer is described, and results of tests on simulated data are presented.

Application of a real-time, calculable limiting form of the Renyi entropy for molecular imaging of tumors.

PubMed

Marsh, Jon N; Wallace, Kirk D; McCarthy, John E; Wickerhauser, Mladen V; Maurizi, Brian N; Lanza, Gregory M; Wickline, Samuel A; Hughes, Michael S

2010-08-01

Previously, we reported new methods for ultrasound signal characterization using entropy, H(f); a generalized entropy, the Renyi entropy, I(f)(r); and a limiting form of Renyi entropy suitable for real-time calculation, I(f),(infinity). All of these quantities demonstrated significantly more sensitivity to subtle changes in scattering architecture than energy-based methods in certain settings. In this study, the real-time calculable limit of the Renyi entropy, I(f),(infinity), is applied for the imaging of angiogenic murine neovasculature in a breast cancer xenograft using a targeted contrast agent. It is shown that this approach may be used to reliably detect the accumulation of targeted nanoparticles at five minutes post-injection in this in vivo model.

Fault Diagnosis for Micro-Gas Turbine Engine Sensors via Wavelet Entropy

PubMed Central

Yu, Bing; Liu, Dongdong; Zhang, Tianhong

2011-01-01

Sensor fault diagnosis is necessary to ensure the normal operation of a gas turbine system. However, the existing methods require too many resources and this need can’t be satisfied in some occasions. Since the sensor readings are directly affected by sensor state, sensor fault diagnosis can be performed by extracting features of the measured signals. This paper proposes a novel fault diagnosis method for sensors based on wavelet entropy. Based on the wavelet theory, wavelet decomposition is utilized to decompose the signal in different scales. Then the instantaneous wavelet energy entropy (IWEE) and instantaneous wavelet singular entropy (IWSE) are defined based on the previous wavelet entropy theory. Subsequently, a fault diagnosis method for gas turbine sensors is proposed based on the results of a numerically simulated example. Then, experiments on this method are carried out on a real micro gas turbine engine. In the experiment, four types of faults with different magnitudes are presented. The experimental results show that the proposed method for sensor fault diagnosis is efficient. PMID:22163734

Fault diagnosis for micro-gas turbine engine sensors via wavelet entropy.

PubMed

Yu, Bing; Liu, Dongdong; Zhang, Tianhong

2011-01-01

Sensor fault diagnosis is necessary to ensure the normal operation of a gas turbine system. However, the existing methods require too many resources and this need can't be satisfied in some occasions. Since the sensor readings are directly affected by sensor state, sensor fault diagnosis can be performed by extracting features of the measured signals. This paper proposes a novel fault diagnosis method for sensors based on wavelet entropy. Based on the wavelet theory, wavelet decomposition is utilized to decompose the signal in different scales. Then the instantaneous wavelet energy entropy (IWEE) and instantaneous wavelet singular entropy (IWSE) are defined based on the previous wavelet entropy theory. Subsequently, a fault diagnosis method for gas turbine sensors is proposed based on the results of a numerically simulated example. Then, experiments on this method are carried out on a real micro gas turbine engine. In the experiment, four types of faults with different magnitudes are presented. The experimental results show that the proposed method for sensor fault diagnosis is efficient.

RNA Thermodynamic Structural Entropy

PubMed Central

Garcia-Martin, Juan Antonio; Clote, Peter

2015-01-01

Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner’99 and Turner’04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http://bioinformatics.bc.edu/clotelab/RNAentropy, including source code and ancillary programs. PMID:26555444

RNA Thermodynamic Structural Entropy.

PubMed

Garcia-Martin, Juan Antonio; Clote, Peter

2015-01-01

Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http://bioinformatics.bc.edu/clotelab/RNAentropy, including source code and ancillary programs.

Quantifying complexity of financial short-term time series by composite multiscale entropy measure

NASA Astrophysics Data System (ADS)

Niu, Hongli; Wang, Jun

2015-05-01

It is significant to study the complexity of financial time series since the financial market is a complex evolved dynamic system. Multiscale entropy is a prevailing method used to quantify the complexity of a time series. Due to its less reliability of entropy estimation for short-term time series at large time scales, a modification method, the composite multiscale entropy, is applied to the financial market. To qualify its effectiveness, its applications in the synthetic white noise and 1 / f noise with different data lengths are reproduced first in the present paper. Then it is introduced for the first time to make a reliability test with two Chinese stock indices. After conducting on short-time return series, the CMSE method shows the advantages in reducing deviations of entropy estimation and demonstrates more stable and reliable results when compared with the conventional MSE algorithm. Finally, the composite multiscale entropy of six important stock indices from the world financial markets is investigated, and some useful and interesting empirical results are obtained.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Maoyuan; Besford, Quinn Alexander; Mulvaney, Thomas

The entropy of hydrophobic solvation has been explained as the result of ordered solvation structures, of hydrogen bonds, of the small size of the water molecule, of dispersion forces, and of solvent density fluctuations. We report a new approach to the calculation of the entropy of hydrophobic solvation, along with tests of and comparisons to several other methods. The methods are assessed in the light of the available thermodynamic and spectroscopic information on the effects of temperature on hydrophobic solvation. Five model hydrophobes in SPC/E water give benchmark solvation entropies via Widom’s test-particle insertion method, and other methods and modelsmore » are tested against these particle-insertion results. Entropies associated with distributions of tetrahedral order, of electric field, and of solvent dipole orientations are examined. We find these contributions are small compared to the benchmark particle-insertion entropy. Competitive with or better than other theories in accuracy, but with no free parameters, is the new estimate of the entropy contributed by correlations between dipole moments. Dipole correlations account for most of the hydrophobic solvation entropy for all models studied and capture the distinctive temperature dependence seen in thermodynamic and spectroscopic experiments. Entropies based on pair and many-body correlations in number density approach the correct magnitudes but fail to describe temperature and size dependences, respectively. Hydrogen-bond definitions and free energies that best reproduce entropies from simulations are reported, but it is difficult to choose one hydrogen bond model that fits a variety of experiments. The use of information theory, scaled-particle theory, and related methods is discussed briefly. Our results provide a test of the Frank-Evans hypothesis that the negative solvation entropy is due to structured water near the solute, complement the spectroscopic detection of that solvation structure by identifying the structural feature responsible for the entropy change, and point to a possible explanation for the observed dependence on length scale. Our key results are that the hydrophobic effect, i.e. the signature, temperature-dependent, solvation entropy of nonpolar molecules in water, is largely due to a dispersion force arising from correlations between rotating permanent dipole moments, that the strength of this force depends on the Kirkwood g-factor, and that the strength of this force may be obtained exactly without simulation.« less

Entanglement Entropy of Black Holes.

PubMed

Solodukhin, Sergey N

2011-01-01

The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as 't Hooft's brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the blackhole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

Entanglement Entropy of Black Holes

NASA Astrophysics Data System (ADS)

Solodukhin, Sergey N.

2011-10-01

The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as 't Hooft's brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the blackhole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

Direct comparison of phase-sensitive vibrational sum frequency generation with maximum entropy method: case study of water.

PubMed

de Beer, Alex G F; Samson, Jean-Sebastièn; Hua, Wei; Huang, Zishuai; Chen, Xiangke; Allen, Heather C; Roke, Sylvie

2011-12-14

We present a direct comparison of phase sensitive sum-frequency generation experiments with phase reconstruction obtained by the maximum entropy method. We show that both methods lead to the same complex spectrum. Furthermore, we discuss the strengths and weaknesses of each of these methods, analyzing possible sources of experimental and analytical errors. A simulation program for maximum entropy phase reconstruction is available at: http://lbp.epfl.ch/. © 2011 American Institute of Physics

Efficient optimization of the quantum relative entropy

NASA Astrophysics Data System (ADS)

Fawzi, Hamza; Fawzi, Omar

2018-04-01

Many quantum information measures can be written as an optimization of the quantum relative entropy between sets of states. For example, the relative entropy of entanglement of a state is the minimum relative entropy to the set of separable states. The various capacities of quantum channels can also be written in this way. We propose a unified framework to numerically compute these quantities using off-the-shelf semidefinite programming solvers, exploiting the approximation method proposed in Fawzi, Saunderson and Parrilo (2017 arXiv: 1705.00812). As a notable application, this method allows us to provide numerical counterexamples for a proposed lower bound on the quantum conditional mutual information in terms of the relative entropy of recovery.

Characterization of Early Partial Seizure Onset: Frequency, Complexity and Entropy

PubMed Central

Jouny, Christophe C.; Bergey, Gregory K.

2011-01-01

Objective A clear classification of partial seizures onset features is not yet established. Complexity and entropy have been very widely used to describe dynamical systems, but a systematic evaluation of these measures to characterize partial seizures has never been performed. Methods Eighteen different measures including power in frequency bands up to 300Hz, Gabor atom density (GAD), Higuchi fractal dimension (HFD), Lempel-Ziv complexity, Shannon entropy, sample entropy, and permutation entropy, were selected to test sensitivity to partial seizure onset. Intracranial recordings from forty-five patients with mesial temporal, neocortical temporal and neocortical extratemporal seizure foci were included (331 partial seizures). Results GAD, Lempel-Ziv complexity, HFD, high frequency activity, and sample entropy were the most reliable measures to assess early seizure onset. Conclusions Increases in complexity and occurrence of high-frequency components appear to be commonly associated with early stages of partial seizure evolution from all regions. The type of measure (frequency-based, complexity or entropy) does not predict the efficiency of the method to detect seizure onset. Significance Differences between measures such as GAD and HFD highlight the multimodal nature of partial seizure onsets. Improved methods for early seizure detection may be achieved from a better understanding of these underlying dynamics. PMID:21872526

Comparison of transfer entropy methods for financial time series

NASA Astrophysics Data System (ADS)

He, Jiayi; Shang, Pengjian

2017-09-01

There is a certain relationship between the global financial markets, which creates an interactive network of global finance. Transfer entropy, a measurement for information transfer, offered a good way to analyse the relationship. In this paper, we analysed the relationship between 9 stock indices from the U.S., Europe and China (from 1995 to 2015) by using transfer entropy (TE), effective transfer entropy (ETE), Rényi transfer entropy (RTE) and effective Rényi transfer entropy (ERTE). We compared the four methods in the sense of the effectiveness for identification of the relationship between stock markets. In this paper, two kinds of information flows are given. One reveals that the U.S. took the leading position when in terms of lagged-current cases, but when it comes to the same date, China is the most influential. And ERTE could provide superior results.

Estimating the Entropy of Binary Time Series: Methodology, Some Theory and a Simulation Study

NASA Astrophysics Data System (ADS)

Gao, Yun; Kontoyiannis, Ioannis; Bienenstock, Elie

2008-06-01

Partly motivated by entropy-estimation problems in neuroscience, we present a detailed and extensive comparison between some of the most popular and effective entropy estimation methods used in practice: The plug-in method, four different estimators based on the Lempel-Ziv (LZ) family of data compression algorithms, an estimator based on the Context-Tree Weighting (CTW) method, and the renewal entropy estimator. METHODOLOGY: Three new entropy estimators are introduced; two new LZ-based estimators, and the “renewal entropy estimator,” which is tailored to data generated by a binary renewal process. For two of the four LZ-based estimators, a bootstrap procedure is described for evaluating their standard error, and a practical rule of thumb is heuristically derived for selecting the values of their parameters in practice. THEORY: We prove that, unlike their earlier versions, the two new LZ-based estimators are universally consistent, that is, they converge to the entropy rate for every finite-valued, stationary and ergodic process. An effective method is derived for the accurate approximation of the entropy rate of a finite-state hidden Markov model (HMM) with known distribution. Heuristic calculations are presented and approximate formulas are derived for evaluating the bias and the standard error of each estimator. SIMULATION: All estimators are applied to a wide range of data generated by numerous different processes with varying degrees of dependence and memory. The main conclusions drawn from these experiments include: (i) For all estimators considered, the main source of error is the bias. (ii) The CTW method is repeatedly and consistently seen to provide the most accurate results. (iii) The performance of the LZ-based estimators is often comparable to that of the plug-in method. (iv) The main drawback of the plug-in method is its computational inefficiency; with small word-lengths it fails to detect longer-range structure in the data, and with longer word-lengths the empirical distribution is severely undersampled, leading to large biases.

Prediction of Protein Configurational Entropy (Popcoen).

PubMed

Goethe, Martin; Gleixner, Jan; Fita, Ignacio; Rubi, J Miguel

2018-03-13

A knowledge-based method for configurational entropy prediction of proteins is presented; this methodology is extremely fast, compared to previous approaches, because it does not involve any type of configurational sampling. Instead, the configurational entropy of a query fold is estimated by evaluating an artificial neural network, which was trained on molecular-dynamics simulations of ∼1000 proteins. The predicted entropy can be incorporated into a large class of protein software based on cost-function minimization/evaluation, in which configurational entropy is currently neglected for performance reasons. Software of this type is used for all major protein tasks such as structure predictions, proteins design, NMR and X-ray refinement, docking, and mutation effect predictions. Integrating the predicted entropy can yield a significant accuracy increase as we show exemplarily for native-state identification with the prominent protein software FoldX. The method has been termed Popcoen for Prediction of Protein Configurational Entropy. An implementation is freely available at http://fmc.ub.edu/popcoen/ .

Interaction Entropy: A New Paradigm for Highly Efficient and Reliable Computation of Protein-Ligand Binding Free Energy.

PubMed

Duan, Lili; Liu, Xiao; Zhang, John Z H

2016-05-04

Efficient and reliable calculation of protein-ligand binding free energy is a grand challenge in computational biology and is of critical importance in drug design and many other molecular recognition problems. The main challenge lies in the calculation of entropic contribution to protein-ligand binding or interaction systems. In this report, we present a new interaction entropy method which is theoretically rigorous, computationally efficient, and numerically reliable for calculating entropic contribution to free energy in protein-ligand binding and other interaction processes. Drastically different from the widely employed but extremely expensive normal mode method for calculating entropy change in protein-ligand binding, the new method calculates the entropic component (interaction entropy or -TΔS) of the binding free energy directly from molecular dynamics simulation without any extra computational cost. Extensive study of over a dozen randomly selected protein-ligand binding systems demonstrated that this interaction entropy method is both computationally efficient and numerically reliable and is vastly superior to the standard normal mode approach. This interaction entropy paradigm introduces a novel and intuitive conceptual understanding of the entropic effect in protein-ligand binding and other general interaction systems as well as a practical method for highly efficient calculation of this effect.

Multi-Scale Low-Entropy Method for Optimizing the Processing Parameters during Automated Fiber Placement.

PubMed

Han, Zhenyu; Sun, Shouzheng; Fu, Hongya; Fu, Yunzhong

2017-09-03

Automated fiber placement (AFP) process includes a variety of energy forms and multi-scale effects. This contribution proposes a novel multi-scale low-entropy method aiming at optimizing processing parameters in an AFP process, where multi-scale effect, energy consumption, energy utilization efficiency and mechanical properties of micro-system could be taken into account synthetically. Taking a carbon fiber/epoxy prepreg as an example, mechanical properties of macro-meso-scale are obtained by Finite Element Method (FEM). A multi-scale energy transfer model is then established to input the macroscopic results into the microscopic system as its boundary condition, which can communicate with different scales. Furthermore, microscopic characteristics, mainly micro-scale adsorption energy, diffusion coefficient entropy-enthalpy values, are calculated under different processing parameters based on molecular dynamics method. Low-entropy region is then obtained in terms of the interrelation among entropy-enthalpy values, microscopic mechanical properties (interface adsorbability and matrix fluidity) and processing parameters to guarantee better fluidity, stronger adsorption, lower energy consumption and higher energy quality collaboratively. Finally, nine groups of experiments are carried out to verify the validity of the simulation results. The results show that the low-entropy optimization method can reduce void content effectively, and further improve the mechanical properties of laminates.

Sample entropy applied to the analysis of synthetic time series and tachograms

NASA Astrophysics Data System (ADS)

Muñoz-Diosdado, A.; Gálvez-Coyt, G. G.; Solís-Montufar, E.

2017-01-01

Entropy is a method of non-linear analysis that allows an estimate of the irregularity of a system, however, there are different types of computational entropy that were considered and tested in order to obtain one that would give an index of signals complexity taking into account the data number of the analysed time series, the computational resources demanded by the method, and the accuracy of the calculation. An algorithm for the generation of fractal time-series with a certain value of β was used for the characterization of the different entropy algorithms. We obtained a significant variation for most of the algorithms in terms of the series size, which could result counterproductive for the study of real signals of different lengths. The chosen method was sample entropy, which shows great independence of the series size. With this method, time series of heart interbeat intervals or tachograms of healthy subjects and patients with congestive heart failure were analysed. The calculation of sample entropy was carried out for 24-hour tachograms and time subseries of 6-hours for sleepiness and wakefulness. The comparison between the two populations shows a significant difference that is accentuated when the patient is sleeping.

Uncertainties have a meaning: Information entropy as a quality measure for 3-D geological models

NASA Astrophysics Data System (ADS)

Wellmann, J. Florian; Regenauer-Lieb, Klaus

2012-03-01

Analyzing, visualizing and communicating uncertainties are important issues as geological models can never be fully determined. To date, there exists no general approach to quantify uncertainties in geological modeling. We propose here to use information entropy as an objective measure to compare and evaluate model and observational results. Information entropy was introduced in the 50s and defines a scalar value at every location in the model for predictability. We show that this method not only provides a quantitative insight into model uncertainties but, due to the underlying concept of information entropy, can be related to questions of data integration (i.e. how is the model quality interconnected with the used input data) and model evolution (i.e. does new data - or a changed geological hypothesis - optimize the model). In other words information entropy is a powerful measure to be used for data assimilation and inversion. As a first test of feasibility, we present the application of the new method to the visualization of uncertainties in geological models, here understood as structural representations of the subsurface. Applying the concept of information entropy on a suite of simulated models, we can clearly identify (a) uncertain regions within the model, even for complex geometries; (b) the overall uncertainty of a geological unit, which is, for example, of great relevance in any type of resource estimation; (c) a mean entropy for the whole model, important to track model changes with one overall measure. These results cannot easily be obtained with existing standard methods. The results suggest that information entropy is a powerful method to visualize uncertainties in geological models, and to classify the indefiniteness of single units and the mean entropy of a model quantitatively. Due to the relationship of this measure to the missing information, we expect the method to have a great potential in many types of geoscientific data assimilation problems — beyond pure visualization.

[Identification of special quality eggs with NIR spectroscopy technology based on symbol entropy feature extraction method].

PubMed

Zhao, Yong; Hong, Wen-Xue

2011-11-01

Fast, nondestructive and accurate identification of special quality eggs is an urgent problem. The present paper proposed a new feature extraction method based on symbol entropy to identify near infrared spectroscopy of special quality eggs. The authors selected normal eggs, free range eggs, selenium-enriched eggs and zinc-enriched eggs as research objects and measured the near-infrared diffuse reflectance spectra in the range of 12 000-4 000 cm(-1). Raw spectra were symbolically represented with aggregation approximation algorithm and symbolic entropy was extracted as feature vector. An error-correcting output codes multiclass support vector machine classifier was designed to identify the spectrum. Symbolic entropy feature is robust when parameter changed and the highest recognition rate reaches up to 100%. The results show that the identification method of special quality eggs using near-infrared is feasible and the symbol entropy can be used as a new feature extraction method of near-infrared spectra.

A two-phase copula entropy-based multiobjective optimization approach to hydrometeorological gauge network design

NASA Astrophysics Data System (ADS)

Xu, Pengcheng; Wang, Dong; Singh, Vijay P.; Wang, Yuankun; Wu, Jichun; Wang, Lachun; Zou, Xinqing; Chen, Yuanfang; Chen, Xi; Liu, Jiufu; Zou, Ying; He, Ruimin

2017-12-01

Hydrometeorological data are needed for obtaining point and areal mean, quantifying the spatial variability of hydrometeorological variables, and calibration and verification of hydrometeorological models. Hydrometeorological networks are utilized to collect such data. Since data collection is expensive, it is essential to design an optimal network based on the minimal number of hydrometeorological stations in order to reduce costs. This study proposes a two-phase copula entropy- based multiobjective optimization approach that includes: (1) copula entropy-based directional information transfer (CDIT) for clustering the potential hydrometeorological gauges into several groups, and (2) multiobjective method for selecting the optimal combination of gauges for regionalized groups. Although entropy theory has been employed for network design before, the joint histogram method used for mutual information estimation has several limitations. The copula entropy-based mutual information (MI) estimation method is shown to be more effective for quantifying the uncertainty of redundant information than the joint histogram (JH) method. The effectiveness of this approach is verified by applying to one type of hydrometeorological gauge network, with the use of three model evaluation measures, including Nash-Sutcliffe Coefficient (NSC), arithmetic mean of the negative copula entropy (MNCE), and MNCE/NSC. Results indicate that the two-phase copula entropy-based multiobjective technique is capable of evaluating the performance of regional hydrometeorological networks and can enable decision makers to develop strategies for water resources management.

Entropy and generalized least square methods in assessment of the regional value of streamgages

USGS Publications Warehouse

Markus, M.; Vernon, Knapp H.; Tasker, Gary D.

2003-01-01

The Illinois State Water Survey performed a study to assess the streamgaging network in the State of Illinois. One of the important aspects of the study was to assess the regional value of each station through an assessment of the information transfer among gaging records for low, average, and high flow conditions. This analysis was performed for the main hydrologic regions in the State, and the stations were initially evaluated using a new approach based on entropy analysis. To determine the regional value of each station within a region, several information parameters, including total net information, were defined based on entropy. Stations were ranked based on the total net information. For comparison, the regional value of the same stations was assessed using the generalized least square regression (GLS) method, developed by the US Geological Survey. Finally, a hybrid combination of GLS and entropy was created by including a function of the negative net information as a penalty function in the GLS. The weights of the combined model were determined to maximize the average correlation with the results of GLS and entropy. The entropy and GLS methods were evaluated using the high-flow data from southern Illinois stations. The combined method was compared with the entropy and GLS approaches using the high-flow data from eastern Illinois stations. ?? 2003 Elsevier B.V. All rights reserved.

DEM interpolation weight calculation modulus based on maximum entropy

NASA Astrophysics Data System (ADS)

Chen, Tian-wei; Yang, Xia

2015-12-01

There is negative-weight in traditional interpolation of gridding DEM, in the article, the principle of Maximum Entropy is utilized to analyze the model system which depends on modulus of space weight. Negative-weight problem of the DEM interpolation is researched via building Maximum Entropy model, and adding nonnegative, first and second order's Moment constraints, the negative-weight problem is solved. The correctness and accuracy of the method was validated with genetic algorithm in matlab program. The method is compared with the method of Yang Chizhong interpolation and quadratic program. Comparison shows that the volume and scaling of Maximum Entropy's weight is fit to relations of space and the accuracy is superior to the latter two.

Compression embedding

DOEpatents

Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

1998-03-10

A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

Compression embedding

DOEpatents

Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

1998-01-01

A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

Entropy generation in Gaussian quantum transformations: applying the replica method to continuous-variable quantum information theory

NASA Astrophysics Data System (ADS)

Gagatsos, Christos N.; Karanikas, Alexandros I.; Kordas, Georgios; Cerf, Nicolas J.

2016-02-01

In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the replica method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression.

Defining new aims for BME programs in Latin America: the case of UAM-Iztapalapa.

PubMed

Azpiroz-Leehan, J; Martinez, L F; Urbina, M E G; Cadena, M M; Sacristan, E

2016-08-01

The need for upkeep and management of medical technology has fostered the creation of a large number of under graduate programs in the field of biomedical Engineering. In Latin America alone, there are over 85 programs dedicated to this. This contrasts with programs in other regions where most of the undergraduates continue on to pursue graduate degrees or work as research and development engineers in the biomedical industry. In this work we analyze the situation regarding curricular design in the 48 BME programs in Mexico and compare this to suggestions and classifications of programs according to needs and possibilities. We then focus on a particular institution, Universidad Autónoma Metropolitana and due to its characteristics and performance we propose that it should redefine its aims from the undergraduate program on, in order to not only generate research but also to provide a nurturing environment for a budding biomedical industry in Mexico.

Calculation of heat transfer on shuttle type configurations including the effects of variable entropy at boundary layer edge

NASA Technical Reports Server (NTRS)

Dejarnette, F. R.

1972-01-01

A relatively simple method is presented for including the effect of variable entropy at the boundary-layer edge in a heat transfer method developed previously. For each inviscid surface streamline an approximate shockwave shape is calculated using a modified form of Maslen's method for inviscid axisymmetric flows. The entropy for the streamline at the edge of the boundary layer is determined by equating the mass flux through the shock wave to that inside the boundary layer. Approximations used in this technique allow the heating rates along each inviscid surface streamline to be calculated independent of the other streamlines. The shock standoff distances computed by the present method are found to compare well with those computed by Maslen's asymmetric method. Heating rates are presented for blunted circular and elliptical cones and a typical space shuttle orbiter at angles of attack. Variable entropy effects are found to increase heating rates downstream of the nose significantly higher than those computed using normal-shock entropy, and turbulent heating rates increased more than laminar rates. Effects of Reynolds number and angles of attack are also shown.

Double symbolic joint entropy in nonlinear dynamic complexity analysis

NASA Astrophysics Data System (ADS)

Yao, Wenpo; Wang, Jun

2017-07-01

Symbolizations, the base of symbolic dynamic analysis, are classified as global static and local dynamic approaches which are combined by joint entropy in our works for nonlinear dynamic complexity analysis. Two global static methods, symbolic transformations of Wessel N. symbolic entropy and base-scale entropy, and two local ones, namely symbolizations of permutation and differential entropy, constitute four double symbolic joint entropies that have accurate complexity detections in chaotic models, logistic and Henon map series. In nonlinear dynamical analysis of different kinds of heart rate variability, heartbeats of healthy young have higher complexity than those of the healthy elderly, and congestive heart failure (CHF) patients are lowest in heartbeats' joint entropy values. Each individual symbolic entropy is improved by double symbolic joint entropy among which the combination of base-scale and differential symbolizations have best complexity analysis. Test results prove that double symbolic joint entropy is feasible in nonlinear dynamic complexity analysis.

Conditional Entropy-Constrained Residual VQ with Application to Image Coding

NASA Technical Reports Server (NTRS)

Kossentini, Faouzi; Chung, Wilson C.; Smith, Mark J. T.

1996-01-01

This paper introduces an extension of entropy-constrained residual vector quantization (VQ) where intervector dependencies are exploited. The method, which we call conditional entropy-constrained residual VQ, employs a high-order entropy conditioning strategy that captures local information in the neighboring vectors. When applied to coding images, the proposed method is shown to achieve better rate-distortion performance than that of entropy-constrained residual vector quantization with less computational complexity and lower memory requirements. Moreover, it can be designed to support progressive transmission in a natural way. It is also shown to outperform some of the best predictive and finite-state VQ techniques reported in the literature. This is due partly to the joint optimization between the residual vector quantizer and a high-order conditional entropy coder as well as the efficiency of the multistage residual VQ structure and the dynamic nature of the prediction.

Minimal entropy approximation for cellular automata

NASA Astrophysics Data System (ADS)

Fukś, Henryk

2014-02-01

We present a method for the construction of approximate orbits of measures under the action of cellular automata which is complementary to the local structure theory. The local structure theory is based on the idea of Bayesian extension, that is, construction of a probability measure consistent with given block probabilities and maximizing entropy. If instead of maximizing entropy one minimizes it, one can develop another method for the construction of approximate orbits, at the heart of which is the iteration of finite-dimensional maps, called minimal entropy maps. We present numerical evidence that the minimal entropy approximation sometimes outperforms the local structure theory in characterizing the properties of cellular automata. The density response curve for elementary CA rule 26 is used to illustrate this claim.

Third law of thermodynamics as a key test of generalized entropies.

PubMed

Bento, E P; Viswanathan, G M; da Luz, M G E; Silva, R

2015-02-01

The laws of thermodynamics constrain the formulation of statistical mechanics at the microscopic level. The third law of thermodynamics states that the entropy must vanish at absolute zero temperature for systems with nondegenerate ground states in equilibrium. Conversely, the entropy can vanish only at absolute zero temperature. Here we ask whether or not generalized entropies satisfy this fundamental property. We propose a direct analytical procedure to test if a generalized entropy satisfies the third law, assuming only very general assumptions for the entropy S and energy U of an arbitrary N-level classical system. Mathematically, the method relies on exact calculation of β=dS/dU in terms of the microstate probabilities p(i). To illustrate this approach, we present exact results for the two best known generalizations of statistical mechanics. Specifically, we study the Kaniadakis entropy S(κ), which is additive, and the Tsallis entropy S(q), which is nonadditive. We show that the Kaniadakis entropy correctly satisfies the third law only for -1<κ<+1, thereby shedding light on why κ is conventionally restricted to this interval. Surprisingly, however, the Tsallis entropy violates the third law for q<1. Finally, we give a concrete example of the power of our proposed method by applying it to a paradigmatic system: the one-dimensional ferromagnetic Ising model with nearest-neighbor interactions.

Configurational entropy: an improvement of the quasiharmonic approximation using configurational temperature.

PubMed

Nguyen, Phuong H; Derreumaux, Philippe

2012-01-14

One challenge in computational biophysics and biology is to develop methodologies able to estimate accurately the configurational entropy of macromolecules. Among many methods, the quasiharmonic approximation (QH) is most widely used as it is simple in both theory and implementation. However, it has been shown that this method becomes inaccurate by overestimating entropy for systems with rugged free energy landscapes. Here, we propose a simple method to improve the QH approximation, i.e., to reduce QH entropy. We approximate the potential energy landscape of the system by an effective harmonic potential, and request that this potential must produce exactly the configurational temperature of the system. Due to this constraint, the force constants associated with the effective harmonic potential are increased, or equivalently, entropy of motion governed by this effective harmonic potential is reduced. We also introduce the effective configurational temperature concept which can be used as an indicator to check the anharmonicity of the free energy landscape. To validate the new method we compare it with the recently developed expansion approximate method by calculating entropy of one simple model system and two peptides with 3 and 16 amino acids either in gas phase or in explicit solvent. We show that the new method appears to be a good choice in practice as it is a compromise between accuracy and computational speed. A modification of the expansion approximate method is also introduced and advantages are discussed in some detail.

Distance-Based Configurational Entropy of Proteins from Molecular Dynamics Simulations

PubMed Central

Fogolari, Federico; Corazza, Alessandra; Fortuna, Sara; Soler, Miguel Angel; VanSchouwen, Bryan; Brancolini, Giorgia; Corni, Stefano; Melacini, Giuseppe; Esposito, Gennaro

2015-01-01

Estimation of configurational entropy from molecular dynamics trajectories is a difficult task which is often performed using quasi-harmonic or histogram analysis. An entirely different approach, proposed recently, estimates local density distribution around each conformational sample by measuring the distance from its nearest neighbors. In this work we show this theoretically well grounded the method can be easily applied to estimate the entropy from conformational sampling. We consider a set of systems that are representative of important biomolecular processes. In particular: reference entropies for amino acids in unfolded proteins are obtained from a database of residues not participating in secondary structure elements;the conformational entropy of folding of β2-microglobulin is computed from molecular dynamics simulations using reference entropies for the unfolded state;backbone conformational entropy is computed from molecular dynamics simulations of four different states of the EPAC protein and compared with order parameters (often used as a measure of entropy);the conformational and rototranslational entropy of binding is computed from simulations of 20 tripeptides bound to the peptide binding protein OppA and of β2-microglobulin bound to a citrate coated gold surface. This work shows the potential of the method in the most representative biological processes involving proteins, and provides a valuable alternative, principally in the shown cases, where other approaches are problematic. PMID:26177039

Distance-Based Configurational Entropy of Proteins from Molecular Dynamics Simulations.

PubMed

Fogolari, Federico; Corazza, Alessandra; Fortuna, Sara; Soler, Miguel Angel; VanSchouwen, Bryan; Brancolini, Giorgia; Corni, Stefano; Melacini, Giuseppe; Esposito, Gennaro

2015-01-01

Estimation of configurational entropy from molecular dynamics trajectories is a difficult task which is often performed using quasi-harmonic or histogram analysis. An entirely different approach, proposed recently, estimates local density distribution around each conformational sample by measuring the distance from its nearest neighbors. In this work we show this theoretically well grounded the method can be easily applied to estimate the entropy from conformational sampling. We consider a set of systems that are representative of important biomolecular processes. In particular: reference entropies for amino acids in unfolded proteins are obtained from a database of residues not participating in secondary structure elements;the conformational entropy of folding of β2-microglobulin is computed from molecular dynamics simulations using reference entropies for the unfolded state;backbone conformational entropy is computed from molecular dynamics simulations of four different states of the EPAC protein and compared with order parameters (often used as a measure of entropy);the conformational and rototranslational entropy of binding is computed from simulations of 20 tripeptides bound to the peptide binding protein OppA and of β2-microglobulin bound to a citrate coated gold surface. This work shows the potential of the method in the most representative biological processes involving proteins, and provides a valuable alternative, principally in the shown cases, where other approaches are problematic.

Sample entropy analysis of cervical neoplasia gene-expression signatures

PubMed Central

Botting, Shaleen K; Trzeciakowski, Jerome P; Benoit, Michelle F; Salama, Salama A; Diaz-Arrastia, Concepcion R

2009-01-01

Background We introduce Approximate Entropy as a mathematical method of analysis for microarray data. Approximate entropy is applied here as a method to classify the complex gene expression patterns resultant of a clinical sample set. Since Entropy is a measure of disorder in a system, we believe that by choosing genes which display minimum entropy in normal controls and maximum entropy in the cancerous sample set we will be able to distinguish those genes which display the greatest variability in the cancerous set. Here we describe a method of utilizing Approximate Sample Entropy (ApSE) analysis to identify genes of interest with the highest probability of producing an accurate, predictive, classification model from our data set. Results In the development of a diagnostic gene-expression profile for cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma of the cervix, we identified 208 genes which are unchanging in all normal tissue samples, yet exhibit a random pattern indicative of the genetic instability and heterogeneity of malignant cells. This may be measured in terms of the ApSE when compared to normal tissue. We have validated 10 of these genes on 10 Normal and 20 cancer and CIN3 samples. We report that the predictive value of the sample entropy calculation for these 10 genes of interest is promising (75% sensitivity, 80% specificity for prediction of cervical cancer over CIN3). Conclusion The success of the Approximate Sample Entropy approach in discerning alterations in complexity from biological system with such relatively small sample set, and extracting biologically relevant genes of interest hold great promise. PMID:19232110

Entropy and climate. I - ERBE observations of the entropy production of the earth

NASA Technical Reports Server (NTRS)

Stephens, G. L.; O'Brien, D. M.

1993-01-01

An approximate method for estimating the global distributions of the entropy fluxes flowing through the upper boundary of the climate system is introduced, and an estimate of the entropy exchange between the earth and space and the entropy production of the planet is provided. Entropy fluxes calculated from the Earth Radiation Budget Experiment measurements show how the long-wave entropy flux densities dominate the total entropy fluxes at all latitudes compared with the entropy flux densities associated with reflected sunlight, although the short-wave flux densities are important in the context of clear sky-cloudy sky net entropy flux differences. It is suggested that the entropy production of the planet is both constant for the 36 months of data considered and very near its maximum possible value. The mean value of this production is 0.68 x 10 exp 15 W/K, and the amplitude of the annual cycle is approximately 1 to 2 percent of this value.

Logarithmic black hole entropy corrections and holographic Rényi entropy

NASA Astrophysics Data System (ADS)

Mahapatra, Subhash

2018-01-01

The entanglement and Rényi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Rényi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order GD^0. The entropic c-function and the inequalities of the Rényi entropy are also satisfied even with the correction terms.

Device-Independent Tests of Entropy

NASA Astrophysics Data System (ADS)

Chaves, Rafael; Brask, Jonatan Bohr; Brunner, Nicolas

2015-09-01

We show that the entropy of a message can be tested in a device-independent way. Specifically, we consider a prepare-and-measure scenario with classical or quantum communication, and develop two different methods for placing lower bounds on the communication entropy, given observable data. The first method is based on the framework of causal inference networks. The second technique, based on convex optimization, shows that quantum communication provides an advantage over classical communication, in the sense of requiring a lower entropy to reproduce given data. These ideas may serve as a basis for novel applications in device-independent quantum information processing.

Harvesting Entropy for Random Number Generation for Internet of Things Constrained Devices Using On-Board Sensors

PubMed Central

Pawlowski, Marcin Piotr; Jara, Antonio; Ogorzalek, Maciej

2015-01-01

Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. In constrained devices of the Internet of Things ecosystem, high entropy random number generators are hard to achieve due to hardware limitations. For the purpose of the random number generation in constrained devices, this work proposes a solution based on the least-significant bits concatenation entropy harvesting method. As a potential source of entropy, on-board integrated sensors (i.e., temperature, humidity and two different light sensors) have been analyzed. Additionally, the costs (i.e., time and memory consumption) of the presented approach have been measured. The results obtained from the proposed method with statistical fine tuning achieved a Shannon entropy of around 7.9 bits per byte of data for temperature and humidity sensors. The results showed that sensor-based random number generators are a valuable source of entropy with very small RAM and Flash memory requirements for constrained devices of the Internet of Things. PMID:26506357

Population entropies estimates of proteins

NASA Astrophysics Data System (ADS)

Low, Wai Yee

2017-05-01

The Shannon entropy equation provides a way to estimate variability of amino acids sequences in a multiple sequence alignment of proteins. Knowledge of protein variability is useful in many areas such as vaccine design, identification of antibody binding sites, and exploration of protein 3D structural properties. In cases where the population entropies of a protein are of interest but only a small sample size can be obtained, a method based on linear regression and random subsampling can be used to estimate the population entropy. This method is useful for comparisons of entropies where the actual sequence counts differ and thus, correction for alignment size bias is needed. In the current work, an R based package named EntropyCorrect that enables estimation of population entropy is presented and an empirical study on how well this new algorithm performs on simulated dataset of various combinations of population and sample sizes is discussed. The package is available at https://github.com/lloydlow/EntropyCorrect. This article, which was originally published online on 12 May 2017, contained an error in Eq. (1), where the summation sign was missing. The corrected equation appears in the Corrigendum attached to the pdf.

Harvesting entropy for random number generation for internet of things constrained devices using on-board sensors.

PubMed

Pawlowski, Marcin Piotr; Jara, Antonio; Ogorzalek, Maciej

2015-10-22

Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. In constrained devices of the Internet of Things ecosystem, high entropy random number generators are hard to achieve due to hardware limitations. For the purpose of the random number generation in constrained devices, this work proposes a solution based on the least-significant bits concatenation entropy harvesting method. As a potential source of entropy, on-board integrated sensors (i.e., temperature, humidity and two different light sensors) have been analyzed. Additionally, the costs (i.e., time and memory consumption) of the presented approach have been measured. The results obtained from the proposed method with statistical fine tuning achieved a Shannon entropy of around 7.9 bits per byte of data for temperature and humidity sensors. The results showed that sensor-based random number generators are a valuable source of entropy with very small RAM and Flash memory requirements for constrained devices of the Internet of Things.

On cell entropy inequality for discontinuous Galerkin methods

NASA Technical Reports Server (NTRS)

Jiang, Guangshan; Shu, Chi-Wang

1993-01-01

We prove a cell entropy inequality for a class of high order discontinuous Galerkin finite element methods approximating conservation laws, which implies convergence for the one dimensional scalar convex case.

Reliability Modeling Development and Its Applications for Ceramic Capacitors with Base-Metal Electrodes (BMEs)

NASA Technical Reports Server (NTRS)

Liu, Donhang

2014-01-01

This presentation includes a summary of NEPP-funded deliverables for the Base-Metal Electrodes (BMEs) capacitor task, development of a general reliability model for BME capacitors, and a summary and future work.

Nonadditive entropy maximization is inconsistent with Bayesian updating

NASA Astrophysics Data System (ADS)

Pressé, Steve

2014-11-01

The maximum entropy method—used to infer probabilistic models from data—is a special case of Bayes's model inference prescription which, in turn, is grounded in basic propositional logic. By contrast to the maximum entropy method, the compatibility of nonadditive entropy maximization with Bayes's model inference prescription has never been established. Here we demonstrate that nonadditive entropy maximization is incompatible with Bayesian updating and discuss the immediate implications of this finding. We focus our attention on special cases as illustrations.

A method for the fast estimation of a battery entropy-variation high-resolution curve - Application on a commercial LiFePO4/graphite cell

NASA Astrophysics Data System (ADS)

Damay, Nicolas; Forgez, Christophe; Bichat, Marie-Pierre; Friedrich, Guy

2016-11-01

The entropy-variation of a battery is responsible for heat generation or consumption during operation and its prior measurement is mandatory for developing a thermal model. It is generally done through the potentiometric method which is considered as a reference. However, it requires several days or weeks to get a look-up table with a 5 or 10% SoC (State of Charge) resolution. In this study, a calorimetric method based on the inversion of a thermal model is proposed for the fast estimation of a nearly continuous curve of entropy-variation. This is achieved by separating the heats produced while charging and discharging the battery. The entropy-variation is then deduced from the extracted entropic heat. The proposed method is validated by comparing the results obtained with several current rates to measurements made with the potentiometric method.

Computation of entropy and Lyapunov exponent by a shift transform.

PubMed

Matsuoka, Chihiro; Hiraide, Koichi

2015-10-01

We present a novel computational method to estimate the topological entropy and Lyapunov exponent of nonlinear maps using a shift transform. Unlike the computation of periodic orbits or the symbolic dynamical approach by the Markov partition, the method presented here does not require any special techniques in computational and mathematical fields to calculate these quantities. In spite of its simplicity, our method can accurately capture not only the chaotic region but also the non-chaotic region (window region) such that it is important physically but the (Lebesgue) measure zero and usually hard to calculate or observe. Furthermore, it is shown that the Kolmogorov-Sinai entropy of the Sinai-Ruelle-Bowen measure (the physical measure) coincides with the topological entropy.

Computation of entropy and Lyapunov exponent by a shift transform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuoka, Chihiro, E-mail: matsuoka.chihiro.mm@ehime-u.ac.jp; Hiraide, Koichi

2015-10-15

We present a novel computational method to estimate the topological entropy and Lyapunov exponent of nonlinear maps using a shift transform. Unlike the computation of periodic orbits or the symbolic dynamical approach by the Markov partition, the method presented here does not require any special techniques in computational and mathematical fields to calculate these quantities. In spite of its simplicity, our method can accurately capture not only the chaotic region but also the non-chaotic region (window region) such that it is important physically but the (Lebesgue) measure zero and usually hard to calculate or observe. Furthermore, it is shown thatmore » the Kolmogorov-Sinai entropy of the Sinai-Ruelle-Bowen measure (the physical measure) coincides with the topological entropy.« less

Convex Accelerated Maximum Entropy Reconstruction

PubMed Central

Worley, Bradley

2016-01-01

Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm – called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm – is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra. PMID:26894476

Complexity Measures in Magnetoencephalography: Measuring "Disorder" in Schizophrenia

PubMed Central

Brookes, Matthew J.; Hall, Emma L.; Robson, Siân E.; Price, Darren; Palaniyappan, Lena; Liddle, Elizabeth B.; Liddle, Peter F.; Robinson, Stephen E.; Morris, Peter G.

2015-01-01

This paper details a methodology which, when applied to magnetoencephalography (MEG) data, is capable of measuring the spatio-temporal dynamics of ‘disorder’ in the human brain. Our method, which is based upon signal entropy, shows that spatially separate brain regions (or networks) generate temporally independent entropy time-courses. These time-courses are modulated by cognitive tasks, with an increase in local neural processing characterised by localised and transient increases in entropy in the neural signal. We explore the relationship between entropy and the more established time-frequency decomposition methods, which elucidate the temporal evolution of neural oscillations. We observe a direct but complex relationship between entropy and oscillatory amplitude, which suggests that these metrics are complementary. Finally, we provide a demonstration of the clinical utility of our method, using it to shed light on aberrant neurophysiological processing in schizophrenia. We demonstrate significantly increased task induced entropy change in patients (compared to controls) in multiple brain regions, including a cingulo-insula network, bilateral insula cortices and a right fronto-parietal network. These findings demonstrate potential clinical utility for our method and support a recent hypothesis that schizophrenia can be characterised by abnormalities in the salience network (a well characterised distributed network comprising bilateral insula and cingulate cortices). PMID:25886553

Unification of field theory and maximum entropy methods for learning probability densities

NASA Astrophysics Data System (ADS)

Kinney, Justin B.

2015-09-01

The need to estimate smooth probability distributions (a.k.a. probability densities) from finite sampled data is ubiquitous in science. Many approaches to this problem have been described, but none is yet regarded as providing a definitive solution. Maximum entropy estimation and Bayesian field theory are two such approaches. Both have origins in statistical physics, but the relationship between them has remained unclear. Here I unify these two methods by showing that every maximum entropy density estimate can be recovered in the infinite smoothness limit of an appropriate Bayesian field theory. I also show that Bayesian field theory estimation can be performed without imposing any boundary conditions on candidate densities, and that the infinite smoothness limit of these theories recovers the most common types of maximum entropy estimates. Bayesian field theory thus provides a natural test of the maximum entropy null hypothesis and, furthermore, returns an alternative (lower entropy) density estimate when the maximum entropy hypothesis is falsified. The computations necessary for this approach can be performed rapidly for one-dimensional data, and software for doing this is provided.

Unification of field theory and maximum entropy methods for learning probability densities.

PubMed

Kinney, Justin B

2015-09-01

The need to estimate smooth probability distributions (a.k.a. probability densities) from finite sampled data is ubiquitous in science. Many approaches to this problem have been described, but none is yet regarded as providing a definitive solution. Maximum entropy estimation and Bayesian field theory are two such approaches. Both have origins in statistical physics, but the relationship between them has remained unclear. Here I unify these two methods by showing that every maximum entropy density estimate can be recovered in the infinite smoothness limit of an appropriate Bayesian field theory. I also show that Bayesian field theory estimation can be performed without imposing any boundary conditions on candidate densities, and that the infinite smoothness limit of these theories recovers the most common types of maximum entropy estimates. Bayesian field theory thus provides a natural test of the maximum entropy null hypothesis and, furthermore, returns an alternative (lower entropy) density estimate when the maximum entropy hypothesis is falsified. The computations necessary for this approach can be performed rapidly for one-dimensional data, and software for doing this is provided.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosales-Zarate, Laura E. C.; Drummond, P. D.

We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. Themore » preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.« less

A new assessment method for urbanization environmental impact: urban environment entropy model and its application.

PubMed

Ouyang, Tingping; Fu, Shuqing; Zhu, Zhaoyu; Kuang, Yaoqiu; Huang, Ningsheng; Wu, Zhifeng

2008-11-01

The thermodynamic law is one of the most widely used scientific principles. The comparability between the environmental impact of urbanization and the thermodynamic entropy was systematically analyzed. Consequently, the concept "Urban Environment Entropy" was brought forward and the "Urban Environment Entropy" model was established for urbanization environmental impact assessment in this study. The model was then utilized in a case study for the assessment of river water quality in the Pearl River Delta Economic Zone. The results indicated that the assessing results of the model are consistent to that of the equalized synthetic pollution index method. Therefore, it can be concluded that the Urban Environment Entropy model has high reliability and can be applied widely in urbanization environmental assessment research using many different environmental parameters.

Applications of quantum entropy to statistics

NASA Astrophysics Data System (ADS)

Silver, R. N.; Martz, H. F.

This paper develops two generalizations of the maximum entropy (ME) principle. First, Shannon classical entropy is replaced by von Neumann quantum entropy to yield a broader class of information divergences (or penalty functions) for statistics applications. Negative relative quantum entropy enforces convexity, positivity, non-local extensivity and prior correlations such as smoothness. This enables the extension of ME methods from their traditional domain of ill-posed in-verse problems to new applications such as non-parametric density estimation. Second, given a choice of information divergence, a combination of ME and Bayes rule is used to assign both prior and posterior probabilities. Hyperparameters are interpreted as Lagrange multipliers enforcing constraints. Conservation principles are proposed to act statistical regularization and other hyperparameters, such as conservation of information and smoothness. ME provides an alternative to hierarchical Bayes methods.

Fast and Efficient Stochastic Optimization for Analytic Continuation

DOE PAGES

Bao, Feng; Zhang, Guannan; Webster, Clayton G; ...

2016-09-28

In this analytic continuation of imaginary-time quantum Monte Carlo data to extract real-frequency spectra remains a key problem in connecting theory with experiment. Here we present a fast and efficient stochastic optimization method (FESOM) as a more accessible variant of the stochastic optimization method introduced by Mishchenko et al. [Phys. Rev. B 62, 6317 (2000)], and we benchmark the resulting spectra with those obtained by the standard maximum entropy method for three representative test cases, including data taken from studies of the two-dimensional Hubbard model. Genearally, we find that our FESOM approach yields spectra similar to the maximum entropy results.more » In particular, while the maximum entropy method yields superior results when the quality of the data is strong, we find that FESOM is able to resolve fine structure with more detail when the quality of the data is poor. In addition, because of its stochastic nature, the method provides detailed information on the frequency-dependent uncertainty of the resulting spectra, while the maximum entropy method does so only for the spectral weight integrated over a finite frequency region. Therefore, we believe that this variant of the stochastic optimization approach provides a viable alternative to the routinely used maximum entropy method, especially for data of poor quality.« less

An entropy correction method for unsteady full potential flows with strong shocks

NASA Technical Reports Server (NTRS)

Whitlow, W., Jr.; Hafez, M. M.; Osher, S. J.

1986-01-01

An entropy correction method for the unsteady full potential equation is presented. The unsteady potential equation is modified to account for entropy jumps across shock waves. The conservative form of the modified equation is solved in generalized coordinates using an implicit, approximate factorization method. A flux-biasing differencing method, which generates the proper amounts of artificial viscosity in supersonic regions, is used to discretize the flow equations in space. Comparisons between the present method and solutions of the Euler equations and between the present method and experimental data are presented. The comparisons show that the present method more accurately models solutions of the Euler equations and experiment than does the isentropic potential formulation.

Multiwavelet packet entropy and its application in transmission line fault recognition and classification.

PubMed

Liu, Zhigang; Han, Zhiwei; Zhang, Yang; Zhang, Qiaoge

2014-11-01

Multiwavelets possess better properties than traditional wavelets. Multiwavelet packet transformation has more high-frequency information. Spectral entropy can be applied as an analysis index to the complexity or uncertainty of a signal. This paper tries to define four multiwavelet packet entropies to extract the features of different transmission line faults, and uses a radial basis function (RBF) neural network to recognize and classify 10 fault types of power transmission lines. First, the preprocessing and postprocessing problems of multiwavelets are presented. Shannon entropy and Tsallis entropy are introduced, and their difference is discussed. Second, multiwavelet packet energy entropy, time entropy, Shannon singular entropy, and Tsallis singular entropy are defined as the feature extraction methods of transmission line fault signals. Third, the plan of transmission line fault recognition using multiwavelet packet entropies and an RBF neural network is proposed. Finally, the experimental results show that the plan with the four multiwavelet packet energy entropies defined in this paper achieves better performance in fault recognition. The performance with SA4 (symmetric antisymmetric) multiwavelet packet Tsallis singular entropy is the best among the combinations of different multiwavelet packets and the four multiwavelet packet entropies.

An improved method for predicting the evolution of the characteristic parameters of an information system

NASA Astrophysics Data System (ADS)

Dushkin, A. V.; Kasatkina, T. I.; Novoseltsev, V. I.; Ivanov, S. V.

2018-03-01

The article proposes a forecasting method that allows, based on the given values of entropy and error level of the first and second kind, to determine the allowable time for forecasting the development of the characteristic parameters of a complex information system. The main feature of the method under consideration is the determination of changes in the characteristic parameters of the development of the information system in the form of the magnitude of the increment in the ratios of its entropy. When a predetermined value of the prediction error ratio is reached, that is, the entropy of the system, the characteristic parameters of the system and the depth of the prediction in time are estimated. The resulting values of the characteristics and will be optimal, since at that moment the system possessed the best ratio of entropy as a measure of the degree of organization and orderliness of the structure of the system. To construct a method for estimating the depth of prediction, it is expedient to use the maximum principle of the value of entropy.

Information Entropy Analysis of the H1N1 Genetic Code

NASA Astrophysics Data System (ADS)

Martwick, Andy

2010-03-01

During the current H1N1 pandemic, viral samples are being obtained from large numbers of infected people world-wide and are being sequenced on the NCBI Influenza Virus Resource Database. The information entropy of the sequences was computed from the probability of occurrence of each nucleotide base at every position of each set of sequences using Shannon's definition of information entropy, [ H=∑bpb,2( 1pb ) ] where H is the observed information entropy at each nucleotide position and pb is the probability of the base pair of the nucleotides A, C, G, U. Information entropy of the current H1N1 pandemic is compared to reference human and swine H1N1 entropy. As expected, the current H1N1 entropy is in a low entropy state and has a very large mutation potential. Using the entropy method in mature genes we can identify low entropy regions of nucleotides that generally correlate to critical protein function.

Ethnic inequalities in limiting health and self-reported health in later life revisited

PubMed Central

Evandrou, Maria; Falkingham, Jane; Feng, Zhixin; Vlachantoni, Athina

2016-01-01

Background It is well established that there are ethnic inequalities in health in the UK; however, such inequalities in later life remain a relatively under-researched area. This paper explores ethnic inequalities in health among older people in the UK, controlling for social and economic disadvantages. Methods This paper analyses the first wave (2009–2011) of Understanding Society to examine differentials in the health of older persons aged 60 years and over. 2 health outcomes are explored: the extent to which one's health limits the ability to undertake typical activities and self-rated health. Logistic regression models are used to control for a range of other factors, including income and deprivation. Results After controlling for social and economic disadvantage, black and minority ethnic (BME) elders are still more likely than white British elders to report limiting health and poor self-rated health. The ‘health disadvantage’ appears most marked among BME elders of South Asian origin, with Pakistani elders exhibiting the poorest health outcomes. Length of time resident in the UK does not have a direct impact on health in models for both genders, but is marginally significant for women. Conclusions Older people from ethnic minorities report poorer health outcomes even after controlling for social and economic disadvantages. This result reflects the complexity of health inequalities among different ethnic groups in the UK, and the need to develop health policies which take into account differences in social and economic resources between different ethnic groups. PMID:26787199

Infrared image segmentation method based on spatial coherence histogram and maximum entropy

NASA Astrophysics Data System (ADS)

Liu, Songtao; Shen, Tongsheng; Dai, Yao

2014-11-01

In order to segment the target well and suppress background noises effectively, an infrared image segmentation method based on spatial coherence histogram and maximum entropy is proposed. First, spatial coherence histogram is presented by weighting the importance of the different position of these pixels with the same gray-level, which is obtained by computing their local density. Then, after enhancing the image by spatial coherence histogram, 1D maximum entropy method is used to segment the image. The novel method can not only get better segmentation results, but also have a faster computation time than traditional 2D histogram-based segmentation methods.

Bayesian or Laplacien inference, entropy and information theory and information geometry in data and signal processing

NASA Astrophysics Data System (ADS)

Mohammad-Djafari, Ali

2015-01-01

The main object of this tutorial article is first to review the main inference tools using Bayesian approach, Entropy, Information theory and their corresponding geometries. This review is focused mainly on the ways these tools have been used in data, signal and image processing. After a short introduction of the different quantities related to the Bayes rule, the entropy and the Maximum Entropy Principle (MEP), relative entropy and the Kullback-Leibler divergence, Fisher information, we will study their use in different fields of data and signal processing such as: entropy in source separation, Fisher information in model order selection, different Maximum Entropy based methods in time series spectral estimation and finally, general linear inverse problems.

State fusion entropy for continuous and site-specific analysis of landslide stability changing regularities

NASA Astrophysics Data System (ADS)

Liu, Yong; Qin, Zhimeng; Hu, Baodan; Feng, Shuai

2018-04-01

Stability analysis is of great significance to landslide hazard prevention, especially the dynamic stability. However, many existing stability analysis methods are difficult to analyse the continuous landslide stability and its changing regularities in a uniform criterion due to the unique landslide geological conditions. Based on the relationship between displacement monitoring data, deformation states and landslide stability, a state fusion entropy method is herein proposed to derive landslide instability through a comprehensive multi-attribute entropy analysis of deformation states, which are defined by a proposed joint clustering method combining K-means and a cloud model. Taking Xintan landslide as the detailed case study, cumulative state fusion entropy presents an obvious increasing trend after the landslide entered accelerative deformation stage and historical maxima match highly with landslide macroscopic deformation behaviours in key time nodes. Reasonable results are also obtained in its application to several other landslides in the Three Gorges Reservoir in China. Combined with field survey, state fusion entropy may serve for assessing landslide stability and judging landslide evolutionary stages.

Entropy-based artificial viscosity stabilization for non-equilibrium Grey Radiation-Hydrodynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delchini, Marc O., E-mail: delchinm@email.tamu.edu; Ragusa, Jean C., E-mail: jean.ragusa@tamu.edu; Morel, Jim, E-mail: jim.morel@tamu.edu

2015-09-01

The entropy viscosity method is extended to the non-equilibrium Grey Radiation-Hydrodynamic equations. The method employs a viscous regularization to stabilize the numerical solution. The artificial viscosity coefficient is modulated by the entropy production and peaks at shock locations. The added dissipative terms are consistent with the entropy minimum principle. A new functional form of the entropy residual, suitable for the Radiation-Hydrodynamic equations, is derived. We demonstrate that the viscous regularization preserves the equilibrium diffusion limit. The equations are discretized with a standard Continuous Galerkin Finite Element Method and a fully implicit temporal integrator within the MOOSE multiphysics framework. The methodmore » of manufactured solutions is employed to demonstrate second-order accuracy in both the equilibrium diffusion and streaming limits. Several typical 1-D radiation-hydrodynamic test cases with shocks (from Mach 1.05 to Mach 50) are presented to establish the ability of the technique to capture and resolve shocks.« less

Renyi entanglement entropy of interacting fermions calculated using the continuous-time quantum Monte Carlo method.

PubMed

Wang, Lei; Troyer, Matthias

2014-09-12

We present a new algorithm for calculating the Renyi entanglement entropy of interacting fermions using the continuous-time quantum Monte Carlo method. The algorithm only samples the interaction correction of the entanglement entropy, which by design ensures the efficient calculation of weakly interacting systems. Combined with Monte Carlo reweighting, the algorithm also performs well for systems with strong interactions. We demonstrate the potential of this method by studying the quantum entanglement signatures of the charge-density-wave transition of interacting fermions on a square lattice.

Understanding materials behavior from atomistic simulations: Case study of al-containing high entropy alloys and thermally grown aluminum oxide

NASA Astrophysics Data System (ADS)

Yinkai Lei

Atomistic simulation refers to a set of simulation methods that model the materials on the atomistic scale. These simulation methods are faster and cheaper alternative approaches to investigate thermodynamics and kinetics of materials compared to experiments. In this dissertation, atomistic simulation methods have been used to study the thermodynamic and kinetic properties of two material systems, i.e. the entropy of Al-containing high entropy alloys (HEAs) and the vacancy migration energy of thermally grown aluminum oxide. (Abstract shortened by ProQuest.).

Surface entropy of liquids via a direct Monte Carlo approach - Application to liquid Si

NASA Technical Reports Server (NTRS)

Wang, Z. Q.; Stroud, D.

1990-01-01

Two methods are presented for a direct Monte Carlo evaluation of the surface entropy S(s) of a liquid interacting by specified, volume-independent potentials. The first method is based on an application of the approach of Ferrenberg and Swendsen (1988, 1989) to Monte Carlo simulations at two different temperatures; it gives much more reliable results for S(s) in liquid Si than previous calculations based on numerical differentiation. The second method expresses the surface entropy directly as a canonical average at fixed temperature.

Dissecting Protein Configurational Entropy into Conformational and Vibrational Contributions.

PubMed

Chong, Song-Ho; Ham, Sihyun

2015-10-01

Quantifying how the rugged nature of the underlying free-energy landscape determines the entropic cost a protein must incur upon folding and ligand binding is a challenging problem. Here, we present a novel computational approach that dissects the protein configurational entropy on the basis of the classification of protein dynamics on the landscape into two separate components: short-term vibrational dynamics related to individual free-energy wells and long-term conformational dynamics associated with transitions between wells. We apply this method to separate the configurational entropy of the protein villin headpiece subdomain into its conformational and vibrational components. We find that the change in configurational entropy upon folding is dominated by the conformational entropy despite the fact that the magnitude of the vibrational entropy is the significantly larger component in each of the folded and unfolded states, which is in accord with the previous empirical estimations. The straightforward applicability of our method to unfolded proteins promises a wide range of applications, including those related to intrinsically disordered proteins.

Modeling Information Content Via Dirichlet-Multinomial Regression Analysis.

PubMed

Ferrari, Alberto

2017-01-01

Shannon entropy is being increasingly used in biomedical research as an index of complexity and information content in sequences of symbols, e.g. languages, amino acid sequences, DNA methylation patterns and animal vocalizations. Yet, distributional properties of information entropy as a random variable have seldom been the object of study, leading to researchers mainly using linear models or simulation-based analytical approach to assess differences in information content, when entropy is measured repeatedly in different experimental conditions. Here a method to perform inference on entropy in such conditions is proposed. Building on results coming from studies in the field of Bayesian entropy estimation, a symmetric Dirichlet-multinomial regression model, able to deal efficiently with the issue of mean entropy estimation, is formulated. Through a simulation study the model is shown to outperform linear modeling in a vast range of scenarios and to have promising statistical properties. As a practical example, the method is applied to a data set coming from a real experiment on animal communication.

Efficient Transfer Entropy Analysis of Non-Stationary Neural Time Series

PubMed Central

Vicente, Raul; Díaz-Pernas, Francisco J.; Wibral, Michael

2014-01-01

Information theory allows us to investigate information processing in neural systems in terms of information transfer, storage and modification. Especially the measure of information transfer, transfer entropy, has seen a dramatic surge of interest in neuroscience. Estimating transfer entropy from two processes requires the observation of multiple realizations of these processes to estimate associated probability density functions. To obtain these necessary observations, available estimators typically assume stationarity of processes to allow pooling of observations over time. This assumption however, is a major obstacle to the application of these estimators in neuroscience as observed processes are often non-stationary. As a solution, Gomez-Herrero and colleagues theoretically showed that the stationarity assumption may be avoided by estimating transfer entropy from an ensemble of realizations. Such an ensemble of realizations is often readily available in neuroscience experiments in the form of experimental trials. Thus, in this work we combine the ensemble method with a recently proposed transfer entropy estimator to make transfer entropy estimation applicable to non-stationary time series. We present an efficient implementation of the approach that is suitable for the increased computational demand of the ensemble method's practical application. In particular, we use a massively parallel implementation for a graphics processing unit to handle the computationally most heavy aspects of the ensemble method for transfer entropy estimation. We test the performance and robustness of our implementation on data from numerical simulations of stochastic processes. We also demonstrate the applicability of the ensemble method to magnetoencephalographic data. While we mainly evaluate the proposed method for neuroscience data, we expect it to be applicable in a variety of fields that are concerned with the analysis of information transfer in complex biological, social, and artificial systems. PMID:25068489

Application of Bayesian Maximum Entropy Filter in parameter calibration of groundwater flow model in PingTung Plain

NASA Astrophysics Data System (ADS)

Cheung, Shao-Yong; Lee, Chieh-Han; Yu, Hwa-Lung

2017-04-01

Due to the limited hydrogeological observation data and high levels of uncertainty within, parameter estimation of the groundwater model has been an important issue. There are many methods of parameter estimation, for example, Kalman filter provides a real-time calibration of parameters through measurement of groundwater monitoring wells, related methods such as Extended Kalman Filter and Ensemble Kalman Filter are widely applied in groundwater research. However, Kalman Filter method is limited to linearity. This study propose a novel method, Bayesian Maximum Entropy Filtering, which provides a method that can considers the uncertainty of data in parameter estimation. With this two methods, we can estimate parameter by given hard data (certain) and soft data (uncertain) in the same time. In this study, we use Python and QGIS in groundwater model (MODFLOW) and development of Extended Kalman Filter and Bayesian Maximum Entropy Filtering in Python in parameter estimation. This method may provide a conventional filtering method and also consider the uncertainty of data. This study was conducted through numerical model experiment to explore, combine Bayesian maximum entropy filter and a hypothesis for the architecture of MODFLOW groundwater model numerical estimation. Through the virtual observation wells to simulate and observe the groundwater model periodically. The result showed that considering the uncertainty of data, the Bayesian maximum entropy filter will provide an ideal result of real-time parameters estimation.

Entropy-based goodness-of-fit test: Application to the Pareto distribution

NASA Astrophysics Data System (ADS)

Lequesne, Justine

2013-08-01

Goodness-of-fit tests based on entropy have been introduced in [13] for testing normality. The maximum entropy distribution in a class of probability distributions defined by linear constraints induces a Pythagorean equality between the Kullback-Leibler information and an entropy difference. This allows one to propose a goodness-of-fit test for maximum entropy parametric distributions which is based on the Kullback-Leibler information. We will focus on the application of the method to the Pareto distribution. The power of the proposed test is computed through Monte Carlo simulation.

Entropy of nonrotating isolated horizons in Lovelock theory from loop quantum gravity

NASA Astrophysics Data System (ADS)

Wang, Jing-Bo; Huang, Chao-Guang; Li, Lin

2016-08-01

In this paper, the BF theory method is applied to the nonrotating isolated horizons in Lovelock theory. The final entropy matches the Wald entropy formula for this theory. We also confirm the conclusion obtained by Bodendorfer et al. that the entropy is related to the flux operator rather than the area operator in general diffeomorphic-invariant theory. Supported by National Natural Science Foundation of China (11275207)

Path length entropy analysis of diastolic heart sounds.

PubMed

Griffel, Benjamin; Zia, Mohammad K; Fridman, Vladamir; Saponieri, Cesare; Semmlow, John L

2013-09-01

Early detection of coronary artery disease (CAD) using the acoustic approach, a noninvasive and cost-effective method, would greatly improve the outcome of CAD patients. To detect CAD, we analyze diastolic sounds for possible CAD murmurs. We observed diastolic sounds to exhibit 1/f structure and developed a new method, path length entropy (PLE) and a scaled version (SPLE), to characterize this structure to improve CAD detection. We compare SPLE results to Hurst exponent, Sample entropy and Multiscale entropy for distinguishing between normal and CAD patients. SPLE achieved a sensitivity-specificity of 80%-81%, the best of the tested methods. However, PLE and SPLE are not sufficient to prove nonlinearity, and evaluation using surrogate data suggests that our cardiovascular sound recordings do not contain significant nonlinear properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Path Length Entropy Analysis of Diastolic Heart Sounds

PubMed Central

Griffel, B.; Zia, M. K.; Fridman, V.; Saponieri, C.; Semmlow, J. L.

2013-01-01

Early detection of coronary artery disease (CAD) using the acoustic approach, a noninvasive and cost-effective method, would greatly improve the outcome of CAD patients. To detect CAD, we analyze diastolic sounds for possible CAD murmurs. We observed diastolic sounds to exhibit 1/f structure and developed a new method, path length entropy (PLE) and a scaled version (SPLE), to characterize this structure to improve CAD detection. We compare SPLE results to Hurst exponent, Sample entropy and Multi-scale entropy for distinguishing between normal and CAD patients. SPLE achieved a sensitivity-specificity of 80%–81%, the best of the tested methods. However, PLE and SPLE are not sufficient to prove nonlinearity, and evaluation using surrogate data suggests that our cardiovascular sound recordings do not contain significant nonlinear properties. PMID:23930808

On the statistical equivalence of restrained-ensemble simulations with the maximum entropy method

PubMed Central

Roux, Benoît; Weare, Jonathan

2013-01-01

An issue of general interest in computer simulations is to incorporate information from experiments into a structural model. An important caveat in pursuing this goal is to avoid corrupting the resulting model with spurious and arbitrary biases. While the problem of biasing thermodynamic ensembles can be formulated rigorously using the maximum entropy method introduced by Jaynes, the approach can be cumbersome in practical applications with the need to determine multiple unknown coefficients iteratively. A popular alternative strategy to incorporate the information from experiments is to rely on restrained-ensemble molecular dynamics simulations. However, the fundamental validity of this computational strategy remains in question. Here, it is demonstrated that the statistical distribution produced by restrained-ensemble simulations is formally consistent with the maximum entropy method of Jaynes. This clarifies the underlying conditions under which restrained-ensemble simulations will yield results that are consistent with the maximum entropy method. PMID:23464140

Using Rényi parameter to improve the predictive power of singular value decomposition entropy on stock market

NASA Astrophysics Data System (ADS)

Jiang, Jiaqi; Gu, Rongbao

2016-04-01

This paper generalizes the method of traditional singular value decomposition entropy by incorporating orders q of Rényi entropy. We analyze the predictive power of the entropy based on trajectory matrix using Shanghai Composite Index and Dow Jones Index data in both static test and dynamic test. In the static test on SCI, results of global granger causality tests all turn out to be significant regardless of orders selected. But this entropy fails to show much predictability in American stock market. In the dynamic test, we find that the predictive power can be significantly improved in SCI by our generalized method but not in DJI. This suggests that noises and errors affect SCI more frequently than DJI. In the end, results obtained using different length of sliding window also corroborate this finding.

EEG entropy measures in anesthesia

PubMed Central

Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

2015-01-01

Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation efficiency compared with MDFA. Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure. Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA. PMID:25741277

Comparison of Texture Analysis Techniques in Both Frequency and Spatial Domains for Cloud Feature Extraction

DTIC Science & Technology

1992-01-01

entropy , energy. variance, skewness, and object. It can also be applied to an image of a phenomenon. It kurtosis. These parameters are then used as...statistic. The co-occurrence matrix method is used in this study to derive texture values of entropy . Limogeneity. energy (similar to the GLDV angular...from working with the co-occurrence matrix method. Seven convolution sizes were chosen to derive the texture values of entropy , local homogeneity, and

Global sensitivity analysis for fuzzy inputs based on the decomposition of fuzzy output entropy

NASA Astrophysics Data System (ADS)

Shi, Yan; Lu, Zhenzhou; Zhou, Yicheng

2018-06-01

To analyse the component of fuzzy output entropy, a decomposition method of fuzzy output entropy is first presented. After the decomposition of fuzzy output entropy, the total fuzzy output entropy can be expressed as the sum of the component fuzzy entropy contributed by fuzzy inputs. Based on the decomposition of fuzzy output entropy, a new global sensitivity analysis model is established for measuring the effects of uncertainties of fuzzy inputs on the output. The global sensitivity analysis model can not only tell the importance of fuzzy inputs but also simultaneously reflect the structural composition of the response function to a certain degree. Several examples illustrate the validity of the proposed global sensitivity analysis, which is a significant reference in engineering design and optimization of structural systems.

Entropy coders for image compression based on binary forward classification

NASA Astrophysics Data System (ADS)

Yoo, Hoon; Jeong, Jechang

2000-12-01

Entropy coders as a noiseless compression method are widely used as final step compression for images, and there have been many contributions to increase of entropy coder performance and to reduction of entropy coder complexity. In this paper, we propose some entropy coders based on the binary forward classification (BFC). The BFC requires overhead of classification but there is no change between the amount of input information and the total amount of classified output information, which we prove this property in this paper. And using the proved property, we propose entropy coders that are the BFC followed by Golomb-Rice coders (BFC+GR) and the BFC followed by arithmetic coders (BFC+A). The proposed entropy coders introduce negligible additional complexity due to the BFC. Simulation results also show better performance than other entropy coders that have similar complexity to the proposed coders.

Advanced hip osteoarthritis: magnetic resonance imaging aspects and histopathology correlations.

PubMed

Leydet-Quilici, H; Le Corroller, T; Bouvier, C; Giorgi, R; Argenson, J-N; Champsaur, P; Pham, T; de Paula, A Maues; Lafforgue, P

2010-11-01

To correlate magnetic resonance imaging (MRI) aspects of the femoral head with histological findings in advanced hip osteoarthritis (OA), with special emphasis on bone marrow edema (BME). MRI was performed in patients with advanced hip OA scheduled for hip arthroplasty. Coronal T1-, fat-suppressed T2-, T1 with gadolinium intravenous injection sequences were obtained on a 1.5 T MR-scanner within 1 month before surgery. Coronal MR images corresponding to the ligamentum teres plane were analyzed by two independent readers blinded to histological data. Normal bone marrow, subchondral cyst, subchondral fracture, edema-like, necrosis-like, and necrosis MR patterns were reported on a synthesis scheme. After surgery, the femoral heads specimens were cut through the ligamentum teres plane and histologically analyzed for correlations. Twenty-three femoral heads were analyzed (female 56.5%, mean age 64.5 years). Edema-like MR pattern was correlated with histological (H) edema (Kappa (K): 0.77). Necrosis-like MR pattern was correlated with H fibrosis (K: 0.49) and with H necrosis (K: 0.24). Cyst MR pattern was correlated with H bone cysts (K: 0.58). Necrosis MR pattern corresponded to a mixture of histological lesions. Sensitivity and specificity of MRI varied from 26% to 80% and from 86% to 95% respectively. In advanced hip OA, the so-called "BME" MR lesion corresponds to a combination of edema, fibrosis, and necrosis at histopathology. When the classical "BME" is more specifically separated into edema-like and necrosis-like MR patterns, MR Imaging and histological findings show substantial agreement, with edema-like MR pattern mainly corresponding to histological edema. Copyright © 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Equality in sexual health promotion: a systematic review of effective interventions for black and minority ethnic men who have sex with men.

PubMed

Fish, Julie; Papaloukas, Periklis; Jaspal, Rusi; Williamson, Iain

2016-08-17

Over the past decade, new diagnoses of HIV have increased eightfold among men who have sex with men (MSM) of other or of mixed ethnicity in the UK. Yet there is little intervention research on HIV among black and minority ethnic (BME) MSM. This article aimed to identify effective HIV and sexual health prevention strategies for BME MSM. We searched three databases PubMed, Scopus and PsychInfo using a combination of search terms: MSM or men who have sex with men and women (MSMW); Black and Minority Ethnic; HIV or sexual health; and evaluation, intervention, program* or implementation. We identified a total of 19 studies to include in the review including those which used randomised control, pre/post-test and cross-sectional design; in addition, we included intervention development studies. A total of 12 studies reported statistically significant results in at least one of the behavioural outcomes assessed; one study reported significant increases in HIV knowledge and changes in safer sex practices. In 10 studies, reductions were reported in unprotected anal intercourse (UAI), number of sexual partners, or in both of these measures. Six out of the 13 studies reported reductions in UAI; while seven reported reductions in number of sexual partners. Seven were intervention development studies. Research into the mechanisms and underpinnings of future sexual health interventions is urgently needed in order to reduce HIV and other sexually transmitted infection (STI) among UK BME MSM. The design of interventions should be informed by the members of these groups for whom they are targeted to ensure the cultural and linguistic sensitivity of the tools and approaches generated.

Internet and patient empowerment in individuals with symptoms of an eating disorder: a cross-sectional investigation of a pro-recovery focused e-community.

PubMed

Aardoom, Jiska J; Dingemans, Alexandra E; Boogaard, Laura H; Van Furth, Eric F

2014-08-01

Many individuals with eating disorder problems seek information and support online. There are however numerous websites that promote eating disordered behaviors. The website and e-community 'Proud2Bme' was developed as a healthy alternative for pro-eating disorder websites, providing a safe, positive, and pro-recovery focused environment. It offers a wide array of information and personal stories, as well as platforms for interaction such as a forum and chat. The first aim of this study was to investigate whether, and to what extent, empowering processes and outcomes are experienced by participants on Proud2Bme. The second aim was to examine correlates of empowering processes and outcomes. Participants (n=311) were recruited via an online survey on Proud2Bme. Correlations were examined and T-tests and ANOVAs were conducted. Exchanging information, finding recognition, and sharing experiences were the empowering processes most often reported by participants. The most pronounced empowering outcome was feeling better informed. To a smaller degree, increased help-seeking behavior, increased optimism and control over the future, and increased confidence in treatment and the relationship with the therapist were reported. Lower levels of general empowerment, younger age, and more interactive usage patterns of the website were positively associated with the experience of empowering processes and outcomes. Offering a platform where individuals can share their experiences and find recognition might be one of the most important ingredients for successful e-health initiatives aimed at improving patient empowerment. Moreover, in the field of eating disorders specifically, such initiatives offer a healthy alternative to the harmful and negative effects of pro-eating disorder websites. Copyright © 2014 Elsevier Ltd. All rights reserved.

A comparative MRI study of cartilage damage in gout versus rheumatoid arthritis.

PubMed

Popovich, Ivor; Lee, Arier C L; Doyle, Anthony; McHaffie, Alexandra; Clarke, Andrew; Reeves, Quentin; Dalbeth, Nicola; McQueen, Fiona M

2015-08-01

Magnetic resonance imaging (MRI) is useful for detecting joint inflammation and damage in the inflammatory arthropathies. This study aimed to investigate MRI cartilage damage and its associations with joint inflammation in patients with gout compared with a group with rheumatoid arthritis (RA). Forty patients with gout and 38 with seropositive RA underwent 3T-MRI of the wrist with assessment of cartilage damage at six carpal sites, using established scoring systems. Synovitis and bone oedema (BME) were graded according to Rheumatoid Arthritis MRI Scoring System criteria. Cartilage damage was compared between the groups adjusting for synovitis and disease duration using logistic regression analysis. Compared with RA, there were fewer sites of cartilage damage and lower total damage scores in the gout group (P = 0.02 and 0.003), adjusting for their longer disease duration and lesser degree of synovitis. Cartilage damage was strongly associated with synovitis in both conditions (R = 0.59, P < 0.0001 and R = 0.52, P = 0.0045 respectively) and highly correlated with BME in RA (R = 0.69, P < 0.0001) but not in gout (R = 0.095, P = 0.56). Cartilage damage is less severe in gout than in RA, with fewer sites affected and lower overall scores. It is associated with synovitis in both diseases, likely indicating an effect of pro-inflammatory cytokine production on cartilage integrity. However, the strong association between cartilage damage and BME observed in RA was not identified in gout. This emphasizes differences in the underlying pathophysiology of joint damage in these two conditions. © 2015 The Royal Australian and New Zealand College of Radiologists.

Growth of the eye lens: II. Allometric studies.

PubMed

Augusteyn, Robert C

2014-01-01

The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated from wet and dry weights with eye volumes calculated from axial length. Linear allometric relationships were obtained for the comparison of ontogenic lens and bodyweight accumulation. The body mass exponent (BME) decreased with increasing animal size from around 1.0 in small rodents to 0.4 in large ungulates for both wet and dry weights. Compaction constants for the ontogenic growth ranged from 1.00 in birds and reptiles up to 1.30 in mammals. Allometric comparison of maximum lens wet and dry weights with maximum bodyweights also yielded linear plots with a BME of 0.504 for all warm blooded species except primates which had a BME of 0.25. When lens volumes were compared with eye volumes, all species yielded a scaling constant of 0.75 but the proportionality constants for primates and birds were lower. Ontogenic lens growth is fastest, relative to body growth, in small animals and slowest in large animals. Fiber cell compaction takes place throughout life in most species, but not in birds and reptiles. Maximum adult lens size scales with eye size with the same exponent in all species, but birds and primates have smaller lenses relative to eye size than other species. Optical properties of the lens are generated through the combination of variations in the rate of growth, rate of compaction, shape and size.

A practical comparison of algorithms for the measurement of multiscale entropy in neural time series data.

PubMed

Kuntzelman, Karl; Jack Rhodes, L; Harrington, Lillian N; Miskovic, Vladimir

2018-06-01

There is a broad family of statistical methods for capturing time series regularity, with increasingly widespread adoption by the neuroscientific community. A common feature of these methods is that they permit investigators to quantify the entropy of brain signals - an index of unpredictability/complexity. Despite the proliferation of algorithms for computing entropy from neural time series data there is scant evidence concerning their relative stability and efficiency. Here we evaluated several different algorithmic implementations (sample, fuzzy, dispersion and permutation) of multiscale entropy in terms of their stability across sessions, internal consistency and computational speed, accuracy and precision using a combination of electroencephalogram (EEG) and synthetic 1/ƒ noise signals. Overall, we report fair to excellent internal consistency and longitudinal stability over a one-week period for the majority of entropy estimates, with several caveats. Computational timing estimates suggest distinct advantages for dispersion and permutation entropy over other entropy estimates. Considered alongside the psychometric evidence, we suggest several ways in which researchers can maximize computational resources (without sacrificing reliability), especially when working with high-density M/EEG data or multivoxel BOLD time series signals. Copyright © 2018 Elsevier Inc. All rights reserved.

Inability of the entropy vector method to certify nonclassicality in linelike causal structures

NASA Astrophysics Data System (ADS)

Weilenmann, Mirjam; Colbeck, Roger

2016-10-01

Bell's theorem shows that our intuitive understanding of causation must be overturned in light of quantum correlations. Nevertheless, quantum mechanics does not permit signaling and hence a notion of cause remains. Understanding this notion is not only important at a fundamental level, but also for technological applications such as key distribution and randomness expansion. It has recently been shown that a useful way to decide which classical causal structures could give rise to a given set of correlations is to use entropy vectors. These are vectors whose components are the entropies of all subsets of the observed variables in the causal structure. The entropy vector method employs causal relationships among the variables to restrict the set of possible entropy vectors. Here, we consider whether the same approach can lead to useful certificates of nonclassicality within a given causal structure. Surprisingly, we find that for a family of causal structures that includes the usual bipartite Bell structure they do not. For all members of this family, no function of the entropies of the observed variables gives such a certificate, in spite of the existence of nonclassical correlations. It is therefore necessary to look beyond entropy vectors to understand cause from a quantum perspective.

Conditional maximum-entropy method for selecting prior distributions in Bayesian statistics

NASA Astrophysics Data System (ADS)

Abe, Sumiyoshi

2014-11-01

The conditional maximum-entropy method (abbreviated here as C-MaxEnt) is formulated for selecting prior probability distributions in Bayesian statistics for parameter estimation. This method is inspired by a statistical-mechanical approach to systems governed by dynamics with largely separated time scales and is based on three key concepts: conjugate pairs of variables, dimensionless integration measures with coarse-graining factors and partial maximization of the joint entropy. The method enables one to calculate a prior purely from a likelihood in a simple way. It is shown, in particular, how it not only yields Jeffreys's rules but also reveals new structures hidden behind them.

Computing a Non-trivial Lower Bound on the Joint Entropy between Two Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perumalla, Kalyan S.

In this report, a non-trivial lower bound on the joint entropy of two non-identical images is developed, which is greater than the individual entropies of the images. The lower bound is the least joint entropy possible among all pairs of images that have the same histograms as those of the given images. New algorithms are presented to compute the joint entropy lower bound with a computation time proportional to S log S where S is the number of histogram bins of the images. This is faster than the traditional methods of computing the exact joint entropy with a computation timemore » that is quadratic in S .« less

Time-series analysis of multiple foreign exchange rates using time-dependent pattern entropy

NASA Astrophysics Data System (ADS)

Ishizaki, Ryuji; Inoue, Masayoshi

2018-01-01

Time-dependent pattern entropy is a method that reduces variations to binary symbolic dynamics and considers the pattern of symbols in a sliding temporal window. We use this method to analyze the instability of daily variations in multiple foreign exchange rates. The time-dependent pattern entropy of 7 foreign exchange rates (AUD/USD, CAD/USD, CHF/USD, EUR/USD, GBP/USD, JPY/USD, and NZD/USD) was found to be high in the long period after the Lehman shock, and be low in the long period after Mar 2012. We compared the correlation matrix between exchange rates in periods of high and low of the time-dependent pattern entropy.

Autonomous entropy-based intelligent experimental design

NASA Astrophysics Data System (ADS)

Malakar, Nabin Kumar

2011-07-01

The aim of this thesis is to explore the application of probability and information theory in experimental design, and to do so in a way that combines what we know about inference and inquiry in a comprehensive and consistent manner. Present day scientific frontiers involve data collection at an ever-increasing rate. This requires that we find a way to collect the most relevant data in an automated fashion. By following the logic of the scientific method, we couple an inference engine with an inquiry engine to automate the iterative process of scientific learning. The inference engine involves Bayesian machine learning techniques to estimate model parameters based upon both prior information and previously collected data, while the inquiry engine implements data-driven exploration. By choosing an experiment whose distribution of expected results has the maximum entropy, the inquiry engine selects the experiment that maximizes the expected information gain. The coupled inference and inquiry engines constitute an autonomous learning method for scientific exploration. We apply it to a robotic arm to demonstrate the efficacy of the method. Optimizing inquiry involves searching for an experiment that promises, on average, to be maximally informative. If the set of potential experiments is described by many parameters, the search involves a high-dimensional entropy space. In such cases, a brute force search method will be slow and computationally expensive. We develop an entropy-based search algorithm, called nested entropy sampling, to select the most informative experiment. This helps to reduce the number of computations necessary to find the optimal experiment. We also extended the method of maximizing entropy, and developed a method of maximizing joint entropy so that it could be used as a principle of collaboration between two robots. This is a major achievement of this thesis, as it allows the information-based collaboration between two robotic units towards a same goal in an automated fashion.

The coupling analysis between stock market indices based on permutation measures

NASA Astrophysics Data System (ADS)

Shi, Wenbin; Shang, Pengjian; Xia, Jianan; Yeh, Chien-Hung

2016-04-01

Many information-theoretic methods have been proposed for analyzing the coupling dependence between time series. And it is significant to quantify the correlation relationship between financial sequences since the financial market is a complex evolved dynamic system. Recently, we developed a new permutation-based entropy, called cross-permutation entropy (CPE), to detect the coupling structures between two synchronous time series. In this paper, we extend the CPE method to weighted cross-permutation entropy (WCPE), to address some of CPE's limitations, mainly its inability to differentiate between distinct patterns of a certain motif and the sensitivity of patterns close to the noise floor. It shows more stable and reliable results than CPE does when applied it to spiky data and AR(1) processes. Besides, we adapt the CPE method to infer the complexity of short-length time series by freely changing the time delay, and test it with Gaussian random series and random walks. The modified method shows the advantages in reducing deviations of entropy estimation compared with the conventional one. Finally, the weighted cross-permutation entropy of eight important stock indices from the world financial markets is investigated, and some useful and interesting empirical results are obtained.

Maximum entropy PDF projection: A review

NASA Astrophysics Data System (ADS)

Baggenstoss, Paul M.

2017-06-01

We review maximum entropy (MaxEnt) PDF projection, a method with wide potential applications in statistical inference. The method constructs a sampling distribution for a high-dimensional vector x based on knowing the sampling distribution p(z) of a lower-dimensional feature z = T (x). Under mild conditions, the distribution p(x) having highest possible entropy among all distributions consistent with p(z) may be readily found. Furthermore, the MaxEnt p(x) may be sampled, making the approach useful in Monte Carlo methods. We review the theorem and present a case study in model order selection and classification for handwritten character recognition.

Crowd macro state detection using entropy model

NASA Astrophysics Data System (ADS)

Zhao, Ying; Yuan, Mengqi; Su, Guofeng; Chen, Tao

2015-08-01

In the crowd security research area a primary concern is to identify the macro state of crowd behaviors to prevent disasters and to supervise the crowd behaviors. The entropy is used to describe the macro state of a self-organization system in physics. The entropy change indicates the system macro state change. This paper provides a method to construct crowd behavior microstates and the corresponded probability distribution using the individuals' velocity information (magnitude and direction). Then an entropy model was built up to describe the crowd behavior macro state. Simulation experiments and video detection experiments were conducted. It was verified that in the disordered state, the crowd behavior entropy is close to the theoretical maximum entropy; while in ordered state, the entropy is much lower than half of the theoretical maximum entropy. The crowd behavior macro state sudden change leads to the entropy change. The proposed entropy model is more applicable than the order parameter model in crowd behavior detection. By recognizing the entropy mutation, it is possible to detect the crowd behavior macro state automatically by utilizing cameras. Results will provide data support on crowd emergency prevention and on emergency manual intervention.

Tackling racism in the NHS.

PubMed

Dean, Erin

2016-11-30

Essential facts Trade union Unite has developed a policy briefing on a new toolkit to combat racism in the NHS. It can help nurses and other staff tackle racial discrimination in health, with black and minority ethnic (BME) nurses often treated unequally compared with their white colleagues.

Complexity in cognitive assessment of elderly British minority ethnic groups: Cultural perspective.

PubMed

Khan, Farooq; Tadros, George

2014-07-01

To study the influence of cultural believes on the acceptance and accessibility of dementia services by patients from British Minority Ethnic (BME) groups. It is noted that non-White ethnic populations rely more on cultural and religious concepts as coping mechanisms to overcome carer stress. In British Punjabi families, ageing was seen as an accepted reason for withdrawal and isolation, and cognitive impairment was rarely identified. Illiteracy added another complexity, only 35% of older Asians in a UK city could speak English, 21% could read and write English, while 73% could read and write in their first language. False positive results using Mini Mental State Examination was found to be 6% of non-impaired white people and 42% of non-impaired black people. Cognitive assessment tests under-estimate the abilities in BME groups. Wide range of variations among white and non-White population were found, contributors are education, language, literacy and culture-specific references. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

An Italian Education: IEEE Pulse talks with Riccardo Pietrabissa, president of Italy's National Bioengineering Group, about Italian progress and challenges in biomedical engineering education.

PubMed

Pietrabissa, Riccardo; Reynolds, Pamela

2015-01-01

From Leonardo da Vinci's designs for ball bearings to the incredible engineering wizardry behind the Ferrari, the inventive, inquisitive, and ingenious spirit of the engineer has always lived--and thrived--in Italy. From education to research to product development, Italy has always been regarded as an engineering leader. But does this apply to biomedical engineering (BME)? Despite many successes, questions loom, as they do at engineering schools worldwide. Concerns such as whether BME programs are providing students with enough focused, practical, hands-on training remain at the forefront, as does the question of whether graduates will be able to find jobs in industry after university studies are over. Here, IEEE Pulse explores these topics with Riccardo Pietrabissa, president of the Gruppo Nazionale di Bioingegneria (National Bioengineering Group) and a full professor in the Department of Chemistry, Materials, and Chemical Engineering at Politecnico di Milano.

Two aspects of black hole entropy in Lanczos-Lovelock models of gravity

NASA Astrophysics Data System (ADS)

Kolekar, Sanved; Kothawala, Dawood; Padmanabhan, T.

2012-03-01

We consider two specific approaches to evaluate the black hole entropy which are known to produce correct results in the case of Einstein’s theory and generalize them to Lanczos-Lovelock models. In the first approach (which could be called extrinsic), we use a procedure motivated by earlier work by Pretorius, Vollick, and Israel, and by Oppenheim, and evaluate the entropy of a configuration of densely packed gravitating shells on the verge of forming a black hole in Lanczos-Lovelock theories of gravity. We find that this matter entropy is not equal to (it is less than) Wald entropy, except in the case of Einstein theory, where they are equal. The matter entropy is proportional to the Wald entropy if we consider a specific mth-order Lanczos-Lovelock model, with the proportionality constant depending on the spacetime dimensions D and the order m of the Lanczos-Lovelock theory as (D-2m)/(D-2). Since the proportionality constant depends on m, the proportionality between matter entropy and Wald entropy breaks down when we consider a sum of Lanczos-Lovelock actions involving different m. In the second approach (which could be called intrinsic), we generalize a procedure, previously introduced by Padmanabhan in the context of general relativity, to study off-shell entropy of a class of metrics with horizon using a path integral method. We consider the Euclidean action of Lanczos-Lovelock models for a class of metrics off shell and interpret it as a partition function. We show that in the case of spherically symmetric metrics, one can interpret the Euclidean action as the free energy and read off both the entropy and energy of a black hole spacetime. Surprisingly enough, this leads to exactly the Wald entropy and the energy of the spacetime in Lanczos-Lovelock models obtained by other methods. We comment on possible implications of the result.

Dispersion entropy for the analysis of resting-state MEG regularity in Alzheimer's disease.

PubMed

Azami, Hamed; Rostaghi, Mostafa; Fernandez, Alberto; Escudero, Javier

2016-08-01

Alzheimer's disease (AD) is a progressive degenerative brain disorder affecting memory, thinking, behaviour and emotion. It is the most common form of dementia and a big social problem in western societies. The analysis of brain activity may help to diagnose this disease. Changes in entropy methods have been reported useful in research studies to characterize AD. We have recently proposed dispersion entropy (DisEn) as a very fast and powerful tool to quantify the irregularity of time series. The aim of this paper is to evaluate the ability of DisEn, in comparison with fuzzy entropy (FuzEn), sample entropy (SampEn), and permutation entropy (PerEn), to discriminate 36 AD patients from 26 elderly control subjects using resting-state magnetoencephalogram (MEG) signals. The results obtained by DisEn, FuzEn, and SampEn, unlike PerEn, show that the AD patients' signals are more regular than controls' time series. The p-values obtained by DisEn, FuzEn, SampEn, and PerEn based methods demonstrate the superiority of DisEn over PerEn, SampEn, and PerEn. Moreover, the computation time for the newly proposed DisEn-based method is noticeably less than for the FuzEn, SampEn, and PerEn based approaches.

Weighted fractional permutation entropy and fractional sample entropy for nonlinear Potts financial dynamics

NASA Astrophysics Data System (ADS)

Xu, Kaixuan; Wang, Jun

2017-02-01

In this paper, recently introduced permutation entropy and sample entropy are further developed to the fractional cases, weighted fractional permutation entropy (WFPE) and fractional sample entropy (FSE). The fractional order generalization of information entropy is utilized in the above two complexity approaches, to detect the statistical characteristics of fractional order information in complex systems. The effectiveness analysis of proposed methods on the synthetic data and the real-world data reveals that tuning the fractional order allows a high sensitivity and more accurate characterization to the signal evolution, which is useful in describing the dynamics of complex systems. Moreover, the numerical research on nonlinear complexity behaviors is compared between the returns series of Potts financial model and the actual stock markets. And the empirical results confirm the feasibility of the proposed model.

Magnetization and isothermal magnetic entropy change of a mixed spin-1 and spin-2 Heisenberg superlattice

NASA Astrophysics Data System (ADS)

Xu, Ping; Du, An

2017-09-01

A superlattice composed of spin-1 and spin-2 with ABAB … structure was described with Heisenberg model. The magnetizations and magnetic entropy changes under different magnetic fields were calculated by the Green's function method. The magnetization compensation phenomenon could be observed by altering the intralayer exchange interactions and the single-ion anisotropies of spins. Along with the temperature increasing, the system in the absence of magnetization compensation shows normal magnetic entropy change and displays a peak near the critical temperature, and yet the system with magnetization compensation shows normal magnetic entropy change near the compensation temperature but inverse magnetic entropy change near the critical temperature. Finally, we illustrated the reasons of different behaviors of magnetic entropy change by analyzing the contributions of two sublattices to the total magnetic entropy change.

Measuring entanglement entropy of a generic many-body system with a quantum switch.

PubMed

Abanin, Dmitry A; Demler, Eugene

2012-07-13

Entanglement entropy has become an important theoretical concept in condensed matter physics because it provides a unique tool for characterizing quantum mechanical many-body phases and new kinds of quantum order. However, the experimental measurement of entanglement entropy in a many-body system is widely believed to be unfeasible, owing to the nonlocal character of this quantity. Here, we propose a general method to measure the entanglement entropy. The method is based on a quantum switch (a two-level system) coupled to a composite system consisting of several copies of the original many-body system. The state of the switch controls how different parts of the composite system connect to each other. We show that, by studying the dynamics of the quantum switch only, the Rényi entanglement entropy of the many-body system can be extracted. We propose a possible design of the quantum switch, which can be realized in cold atomic systems. Our work provides a route towards testing the scaling of entanglement in critical systems as well as a method for a direct experimental detection of topological order.

Application of the Maximum Entropy Method to Risk Analysis of Mergers and Acquisitions

NASA Astrophysics Data System (ADS)

Xie, Jigang; Song, Wenyun

The maximum entropy (ME) method can be used to analyze the risk of mergers and acquisitions when only pre-acquisition information is available. A practical example of the risk analysis of China listed firms’ mergers and acquisitions is provided to testify the feasibility and practicality of the method.

Binarized cross-approximate entropy in crowdsensing environment.

PubMed

Skoric, Tamara; Mohamoud, Omer; Milovanovic, Branislav; Japundzic-Zigon, Nina; Bajic, Dragana

2017-01-01

Personalised monitoring in health applications has been recognised as part of the mobile crowdsensing concept, where subjects equipped with sensors extract information and share them for personal or common benefit. Limited transmission resources impose the use of local analyses methodology, but this approach is incompatible with analytical tools that require stationary and artefact-free data. This paper proposes a computationally efficient binarised cross-approximate entropy, referred to as (X)BinEn, for unsupervised cardiovascular signal processing in environments where energy and processor resources are limited. The proposed method is a descendant of the cross-approximate entropy ((X)ApEn). It operates on binary, differentially encoded data series split into m-sized vectors. The Hamming distance is used as a distance measure, while a search for similarities is performed on the vector sets. The procedure is tested on rats under shaker and restraint stress, and compared to the existing (X)ApEn results. The number of processing operations is reduced. (X)BinEn captures entropy changes in a similar manner to (X)ApEn. The coding coarseness yields an adverse effect of reduced sensitivity, but it attenuates parameter inconsistency and binary bias. A special case of (X)BinEn is equivalent to Shannon's entropy. A binary conditional entropy for m =1 vectors is embedded into the (X)BinEn procedure. (X)BinEn can be applied to a single time series as an auto-entropy method, or to a pair of time series, as a cross-entropy method. Its low processing requirements makes it suitable for mobile, battery operated, self-attached sensing devices, with limited power and processor resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Event by event analysis and entropy of multiparticle systems

NASA Astrophysics Data System (ADS)

Bialas, A.; Czyz, W.

2000-04-01

The coincidence method of measuring the entropy of a system, proposed some time ago by Ma, is generalized to include systems out of equilibrium. It is suggested that the method can be adapted to analyze multiparticle states produced in high-energy collisions.

Fine structure of the entanglement entropy in the O(2) model.

PubMed

Yang, Li-Ping; Liu, Yuzhi; Zou, Haiyuan; Xie, Z Y; Meurice, Y

2016-01-01

We compare two calculations of the particle density in the superfluid phase of the O(2) model with a chemical potential μ in 1+1 dimensions. The first relies on exact blocking formulas from the Tensor Renormalization Group (TRG) formulation of the transfer matrix. The second is a worm algorithm. We show that the particle number distributions obtained with the two methods agree well. We use the TRG method to calculate the thermal entropy and the entanglement entropy. We describe the particle density, the two entropies and the topology of the world lines as we increase μ to go across the superfluid phase between the first two Mott insulating phases. For a sufficiently large temporal size, this process reveals an interesting fine structure: the average particle number and the winding number of most of the world lines in the Euclidean time direction increase by one unit at a time. At each step, the thermal entropy develops a peak and the entanglement entropy increases until we reach half-filling and then decreases in a way that approximately mirrors the ascent. This suggests an approximate fermionic picture.

Probing the extensive nature of entropy

NASA Astrophysics Data System (ADS)

Salagaram, T.; Chetty, N.

2013-08-01

We have devised a general numerical scheme applied to a system of independent, distinguishable, non-interacting particles, to demonstrate in a direct manner the extensive nature of statistical entropy. Working within the microcanonical ensemble, our methods enable one to directly monitor the approach to the thermodynamic limit (N → ∞) in a manner that has not been known before. We show that (sN - s∞) → N-α where sN is the entropy per particle for N particles and S∞ is the entropy per particle in the thermodynamic limit. We demonstrate universal behaviour by considering a number of different systems each defined by its unique single-particle spectrum. Various thermodynamic quantities as a function of N may be computed using our methods; in this paper, we focus on the entropy, the chemical potential and the temperature. Our results are applicable to systems of finite size, e.g. nano-particle systems. Furthermore, we demonstrate a new phenomenon, referred to as entropic interference, which manifests as a cancellation of terms in the thermodynamic limit and which results in the additive nature of entropy.

Entropy-Based Registration of Point Clouds Using Terrestrial Laser Scanning and Smartphone GPS.

PubMed

Chen, Maolin; Wang, Siying; Wang, Mingwei; Wan, Youchuan; He, Peipei

2017-01-20

Automatic registration of terrestrial laser scanning point clouds is a crucial but unresolved topic that is of great interest in many domains. This study combines terrestrial laser scanner with a smartphone for the coarse registration of leveled point clouds with small roll and pitch angles and height differences, which is a novel sensor combination mode for terrestrial laser scanning. The approximate distance between two neighboring scan positions is firstly calculated with smartphone GPS coordinates. Then, 2D distribution entropy is used to measure the distribution coherence between the two scans and search for the optimal initial transformation parameters. To this end, we propose a method called Iterative Minimum Entropy (IME) to correct initial transformation parameters based on two criteria: the difference between the average and minimum entropy and the deviation from the minimum entropy to the expected entropy. Finally, the presented method is evaluated using two data sets that contain tens of millions of points from panoramic and non-panoramic, vegetation-dominated and building-dominated cases and can achieve high accuracy and efficiency.

Judging The Effectiveness Of Wool Combing By The Entropy Of The Images Of Wool Slivers

NASA Astrophysics Data System (ADS)

Rodrigues, F. Carvalho; Carvalho, Fernando D.; Peixoto, J. Pinto; Silva, M. Santos

1989-04-01

In general it can be said that the textile industry endeavours to render a bunch of fibers chaotically distributed in space into an ordered spatial distribution. This fact is independent of the nature the fibers, i.e., the aim of getting into higher order states in the spatial distribution of the fibers dictates different industrial processes depending on whether the fibers are wool, cotton or man made but the all effect is centred on obtaining at every step of any of the processes a more ordered state regarding the spatial distribution of the fibers. Thinking about the textile processes as a method of getting order out of chaos, the concept of entropy appears as the most appropriate judging parameter on the effectiveness of a step in the chain of an industrial process to produce a regular textile. In fact, entropy is the hidden parameter not only for the textile industry but also for the non woven and paper industrial processes. It happens that in these industries the state of order is linked with the spatial distribution of fibers and to obtain an image of a spatial distribution is an easy matter. To compute the image entropy from the grey level distribution requires only the use of the Shannon formula. In this paper to illustrate the usefulness of employing the entropy of an image concept to textiles the evolution of the entropy of wool slivers along the combing process is matched against the state of parallelization of the fibbers along the seven steps as measured by the existing method. The advantages of the entropy method over the previous method based on diffraction is also demonstrated.

Critical evaluation of methods to incorporate entropy loss upon binding in high-throughput docking.

PubMed

Salaniwal, Sumeet; Manas, Eric S; Alvarez, Juan C; Unwalla, Rayomand J

2007-02-01

Proper accounting of the positional/orientational/conformational entropy loss associated with protein-ligand binding is important to obtain reliable predictions of binding affinity. Herein, we critically examine two simplified statistical mechanics-based approaches, namely a constant penalty per rotor method, and a more rigorous method, referred to here as the partition function-based scoring (PFS) method, to account for such entropy losses in high-throughput docking calculations. Our results on the estrogen receptor beta and dihydrofolate reductase proteins demonstrate that, while the constant penalty method over-penalizes molecules for their conformational flexibility, the PFS method behaves in a more "DeltaG-like" manner by penalizing different rotors differently depending on their residual entropy in the bound state. Furthermore, in contrast to no entropic penalty or the constant penalty approximation, the PFS method does not exhibit any bias towards either rigid or flexible molecules in the hit list. Preliminary enrichment studies using a lead-like random molecular database suggest that an accurate representation of the "true" energy landscape of the protein-ligand complex is critical for reliable predictions of relative binding affinities by the PFS method. Copyright 2006 Wiley-Liss, Inc.

Pregnancy as an ideal time for intervention to address the complex needs of black and minority ethnic women: views of British midwives.

PubMed

Aquino, Maria Raisa Jessica V; Edge, Dawn; Smith, Debbie M

2015-03-01

maternal health inequalities exist across the world. In the United Kingdom, whilst there are variations within and between groups, Black and Minority Ethnic (BME) women tend to have worse maternal health outcomes than White British women. However, there is limited information about BME women's experience of maternity services. Midwives are central to the provision of safe maternity care but little is known about their perceptions of ethnically-based inequalities in maternal healthcare. Therefore, this study explored a cohort of midwives' experiences of providing care for BME women, focussing on their views on the relationship between maternal health inequalities and service delivery. using a specifically-designed topic guide, 20 semi-structured interviews were conducted with qualified midwives in one National Health Service (NHS) Trust in the North West of England over a two-month period. Data were subsequently transcribed and thematically analysed. three main and seven sub-themes were identified. Firstly, 'language' summarised difficulties midwives experienced in engaging with women whose English was limited. Secondly, 'expectations of maternity care' outlined the mismatch between midwives and women's expectations of maternity care. Finally, 'complex needs extending beyond maternity care' highlighted the necessity of inter-agency working to address women's care holistically when their needs transcend the scope of maternity services. Midwives' accounts indicated that they strive to provide equitable care but encountered numerous barriers in doing so. Paradoxically, this might contribute to inequalities in service delivery. In midwives' view, unrestricted access to interpretation and translation services is essential for provision of effective, holistic maternity care. Participants also advocated education for both women and midwives. For the former, this would improve BME women's understanding of health and care systems, potentially leading to more realistic expectations. Improving midwives' cultural competence would better equip them to respond to the needs of an ethnically diverse population. Finally, midwives highlighted that many minority women's complex care needs were identified during pregnancy. Hence, they regarded pregnancy as an ideal time for interventions to improve the health of women and their families and, as such, antenatal care cannot be treated as an isolated event. According to midwives in this study, delivering safe, effective maternity services in the 21st century requires greater collaboration with the women they care for and other health and care agencies (including independent sector providers). Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Shannon information entropy in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Ma, Chun-Wang; Ma, Yu-Gang

2018-03-01

The general idea of information entropy provided by C.E. Shannon "hangs over everything we do" and can be applied to a great variety of problems once the connection between a distribution and the quantities of interest is found. The Shannon information entropy essentially quantify the information of a quantity with its specific distribution, for which the information entropy based methods have been deeply developed in many scientific areas including physics. The dynamical properties of heavy-ion collisions (HICs) process make it difficult and complex to study the nuclear matter and its evolution, for which Shannon information entropy theory can provide new methods and observables to understand the physical phenomena both theoretically and experimentally. To better understand the processes of HICs, the main characteristics of typical models, including the quantum molecular dynamics models, thermodynamics models, and statistical models, etc., are briefly introduced. The typical applications of Shannon information theory in HICs are collected, which cover the chaotic behavior in branching process of hadron collisions, the liquid-gas phase transition in HICs, and the isobaric difference scaling phenomenon for intermediate mass fragments produced in HICs of neutron-rich systems. Even though the present applications in heavy-ion collision physics are still relatively simple, it would shed light on key questions we are seeking for. It is suggested to further develop the information entropy methods in nuclear reactions models, as well as to develop new analysis methods to study the properties of nuclear matters in HICs, especially the evolution of dynamics system.

Entropy Viscosity and L1-based Approximations of PDEs: Exploiting Sparsity

DTIC Science & Technology

2015-10-23

AFRL-AFOSR-VA-TR-2015-0337 Entropy Viscosity and L1-based Approximations of PDEs: Exploiting Sparsity Jean-Luc Guermond TEXAS A & M UNIVERSITY 750...REPORT DATE (DD-MM-YYYY) 09-05-2015 2. REPORT TYPE Final report 3. DATES COVERED (From - To) 01-07-2012 - 30-06-2015 4. TITLE AND SUBTITLE Entropy ...conservation equations can be stabilized by using the so-called entropy viscosity method and we proposed to to investigate this new technique. We

Bayesian framework inspired no-reference region-of-interest quality measure for brain MRI images

PubMed Central

Osadebey, Michael; Pedersen, Marius; Arnold, Douglas; Wendel-Mitoraj, Katrina

2017-01-01

Abstract. We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed. Prior belief in each entropy region is determined from normalized total clique potential (TCP) energy of the slice. For TCP below the predefined threshold, the prior probability for a region is determined by deviation of its percentage composition in the slice from a standard normal distribution built from 250 MRI volume data provided by Alzheimer’s Disease Neuroimaging Initiative. For TCP above the threshold, the prior is computed using a mathematical model that describes the TCP–noise level relationship in brain MRI images. Our proposed method assesses the image quality of each entropy region and the global image. Experimental results demonstrate good correlation with subjective opinions of radiologists for different types and levels of quality distortions. PMID:28630885

The entropy of the life table: A reappraisal.

PubMed

Fernandez, Oscar E; Beltrán-Sánchez, Hiram

2015-09-01

The life table entropy provides useful information for understanding improvements in mortality and survival in a population. In this paper we take a closer look at the life table entropy and use advanced mathematical methods to provide additional insights for understanding how it relates to changes in mortality and survival. By studying the entropy (H) as a functional, we show that changes in the entropy depend on both the relative change in life expectancy lost due to death (e(†)) and in life expectancy at birth (e0). We also show that changes in the entropy can be further linked to improvements in premature and older deaths. We illustrate our methods with empirical data from Latin American countries, which suggests that at high mortality levels declines in H (which are associated with survival increases) linked with larger improvements in e0, whereas at low mortality levels e(†) made larger contributions to H. We additionally show that among countries with low mortality level, contributions of e(†) to changes in the life table entropy resulted from averting early deaths. These findings indicate that future increases in overall survival in low mortality countries will likely result from improvements in e(†). Copyright © 2015 Elsevier Inc. All rights reserved.

Optimization of a Circular Microchannel With Entropy Generation Minimization Method

NASA Astrophysics Data System (ADS)

Jafari, Arash; Ghazali, Normah Mohd

2010-06-01

New advances in micro and nano scales are being realized and the contributions of micro and nano heat dissipation devices are of high importance in this novel technology development. Past studies showed that microchannel design depends on its thermal resistance and pressure drop. However, entropy generation minimization (EGM) as a new optimization theory stated that the rate of entropy generation should be also optimized. Application of EGM in microchannel heat sink design is reviewed and discussed in this paper. Latest principles for deriving the entropy generation relations are discussed to present how this approach can be achieved. An optimization procedure using EGM method with the entropy generation rate is derived for a circular microchannel heat sink based upon thermal resistance and pressure drop. The equations are solved using MATLAB and the obtained results are compared to similar past studies. The effects of channel diameter, number of channels, heat flux, and pumping power on the entropy generation rate and Reynolds number are investigated. Analytical correlations are utilized for heat transfer and friction coefficients. A minimum entropy generation has been observed for N = 40 and channel diameter of 90μm. It is concluded that for N = 40 and channel hydraulic diameter of 90μm, the circular microchannel heat sink is on its optimum operating point based on second law of thermodynamics.

An entropy-based statistic for genomewide association studies.

PubMed

Zhao, Jinying; Boerwinkle, Eric; Xiong, Momiao

2005-07-01

Efficient genotyping methods and the availability of a large collection of single-nucleotide polymorphisms provide valuable tools for genetic studies of human disease. The standard chi2 statistic for case-control studies, which uses a linear function of allele frequencies, has limited power when the number of marker loci is large. We introduce a novel test statistic for genetic association studies that uses Shannon entropy and a nonlinear function of allele frequencies to amplify the differences in allele and haplotype frequencies to maintain statistical power with large numbers of marker loci. We investigate the relationship between the entropy-based test statistic and the standard chi2 statistic and show that, in most cases, the power of the entropy-based statistic is greater than that of the standard chi2 statistic. The distribution of the entropy-based statistic and the type I error rates are validated using simulation studies. Finally, we apply the new entropy-based test statistic to two real data sets, one for the COMT gene and schizophrenia and one for the MMP-2 gene and esophageal carcinoma, to evaluate the performance of the new method for genetic association studies. The results show that the entropy-based statistic obtained smaller P values than did the standard chi2 statistic.

Microscopic insights into the NMR relaxation based protein conformational entropy meter

PubMed Central

Kasinath, Vignesh; Sharp, Kim A.; Wand, A. Joshua

2013-01-01

Conformational entropy is a potentially important thermodynamic parameter contributing to protein function. Quantitative measures of conformational entropy are necessary for an understanding of its role but have been difficult to obtain. An empirical method that utilizes changes in conformational dynamics as a proxy for changes in conformational entropy has recently been introduced. Here we probe the microscopic origins of the link between conformational dynamics and conformational entropy using molecular dynamics simulations. Simulation of seven pro! teins gave an excellent correlation with measures of side-chain motion derived from NMR relaxation. The simulations show that the motion of methyl-bearing side-chains are sufficiently coupled to that of other side chains to serve as excellent reporters of the overall side-chain conformational entropy. These results tend to validate the use of experimentally accessible measures of methyl motion - the NMR-derived generalized order parameters - as a proxy from which to derive changes in protein conformational entropy. PMID:24007504

Secure self-calibrating quantum random-bit generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiorentino, M.; Santori, C.; Spillane, S. M.

2007-03-15

Random-bit generators (RBGs) are key components of a variety of information processing applications ranging from simulations to cryptography. In particular, cryptographic systems require 'strong' RBGs that produce high-entropy bit sequences, but traditional software pseudo-RBGs have very low entropy content and therefore are relatively weak for cryptography. Hardware RBGs yield entropy from chaotic or quantum physical systems and therefore are expected to exhibit high entropy, but in current implementations their exact entropy content is unknown. Here we report a quantum random-bit generator (QRBG) that harvests entropy by measuring single-photon and entangled two-photon polarization states. We introduce and implement a quantum tomographicmore » method to measure a lower bound on the 'min-entropy' of the system, and we employ this value to distill a truly random-bit sequence. This approach is secure: even if an attacker takes control of the source of optical states, a secure random sequence can be distilled.« less

Consistent Application of the Boltzmann Distribution to Residual Entropy in Crystals

ERIC Educational Resources Information Center

Kozliak, Evguenii I.

2007-01-01

Four different approaches to residual entropy (the entropy remaining in crystals comprised of nonsymmetric molecules like CO, N[subscript 2]O, FClO[subscript 3], and H[subscript 2]O as temperatures approach 0 K) are analyzed and a new method of its calculation is developed based on application of the Boltzmann distribution. The inherent connection…

How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems.

PubMed

Hanel, Rudolf; Thurner, Stefan; Gell-Mann, Murray

2014-05-13

The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there has been an ongoing controversy over whether the notion of the maximum entropy principle can be extended in a meaningful way to nonextensive, nonergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for nonergodic and complex statistical systems if their relative entropy can be factored into a generalized multiplicity and a constraint term. The problem of finding such a factorization reduces to finding an appropriate representation of relative entropy in a linear basis. In a particular example we show that path-dependent random processes with memory naturally require specific generalized entropies. The example is to our knowledge the first exact derivation of a generalized entropy from the microscopic properties of a path-dependent random process.

Modeling Loop Entropy

PubMed Central

Chirikjian, Gregory S.

2011-01-01

Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting ‘the’ tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of ‘entropy’ is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice; each of the above with different solvation and solvent models; thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics and information theory. PMID:21187223

Measurement of entanglement entropy in the two-dimensional Potts model using wavelet analysis.

PubMed

Tomita, Yusuke

2018-05-01

A method is introduced to measure the entanglement entropy using a wavelet analysis. Using this method, the two-dimensional Haar wavelet transform of a configuration of Fortuin-Kasteleyn (FK) clusters is performed. The configuration represents a direct snapshot of spin-spin correlations since spin degrees of freedom are traced out in FK representation. A snapshot of FK clusters loses image information at each coarse-graining process by the wavelet transform. It is shown that the loss of image information measures the entanglement entropy in the Potts model.

Nonlinear dynamics applied to the study of cardiovascular effects of stress

NASA Astrophysics Data System (ADS)

Anishchenko, T. G.; Igosheva, N. B.

1998-03-01

We study cardiovascular responses to emotional stresses in humans and rats using traditional physiological parameters and methods of nonlinear dynamics. We found that emotional stress results in significant changes of chaos degree of ECG and blood pressure signals, estimated using a normalized entropy. We demonstrate that the normalized entropy is a more sensitive indicator of the stress-induced changes in cardiovascular systems compared with traditional physiological parameters Using the normalized entropy we discovered the significant individual differences in cardiovascular stress-reactivity that was impossible to obtain by traditional physiological methods.

Time-series analysis of foreign exchange rates using time-dependent pattern entropy

NASA Astrophysics Data System (ADS)

Ishizaki, Ryuji; Inoue, Masayoshi

2013-08-01

Time-dependent pattern entropy is a method that reduces variations to binary symbolic dynamics and considers the pattern of symbols in a sliding temporal window. We use this method to analyze the instability of daily variations in foreign exchange rates, in particular, the dollar-yen rate. The time-dependent pattern entropy of the dollar-yen rate was found to be high in the following periods: before and after the turning points of the yen from strong to weak or from weak to strong, and the period after the Lehman shock.

Inverting ion images without Abel inversion: maximum entropy reconstruction of velocity maps.

PubMed

Dick, Bernhard

2014-01-14

A new method for the reconstruction of velocity maps from ion images is presented, which is based on the maximum entropy concept. In contrast to other methods used for Abel inversion the new method never applies an inversion or smoothing to the data. Instead, it iteratively finds the map which is the most likely cause for the observed data, using the correct likelihood criterion for data sampled from a Poissonian distribution. The entropy criterion minimizes the information content in this map, which hence contains no information for which there is no evidence in the data. Two implementations are proposed, and their performance is demonstrated with simulated and experimental data: Maximum Entropy Velocity Image Reconstruction (MEVIR) obtains a two-dimensional slice through the velocity distribution and can be compared directly to Abel inversion. Maximum Entropy Velocity Legendre Reconstruction (MEVELER) finds one-dimensional distribution functions Q(l)(v) in an expansion of the velocity distribution in Legendre polynomials P((cos θ) for the angular dependence. Both MEVIR and MEVELER can be used for the analysis of ion images with intensities as low as 0.01 counts per pixel, with MEVELER performing significantly better than MEVIR for images with low intensity. Both methods perform better than pBASEX, in particular for images with less than one average count per pixel.

Grounding, Bonding, Shielding, and Lightning Bibliography 1972 to 1979

DTIC Science & Technology

1981-02-01

Transactions on Biomedical Engineering, vol. BME -22, no. 1, 3anuary 1975, pp. 62-65. Several basic facts about the effects of steel conduits in a.c. power...34 Institution of Engineers, Australia, Electrical Engineering Transactions, (Australia), vol. EE- 14, no. 2, 1978, pp. 73-77. Statistics on Australian

Access to cancer services--do culture and ethnicity make a difference?

PubMed

Thompson, Rose; Van Der Molen, Beverley

2009-01-01

This module discusses the diverse cultural needs of people affected by cancer and how those needs can be assessed and met. The UK experience with Black or Minority Ethnic (BME) communities will be used to explore the issues of awareness of and detection of cancer.

Measuring Complexity and Predictability of Time Series with Flexible Multiscale Entropy for Sensor Networks

PubMed Central

Zhou, Renjie; Yang, Chen; Wan, Jian; Zhang, Wei; Guan, Bo; Xiong, Naixue

2017-01-01

Measurement of time series complexity and predictability is sometimes the cornerstone for proposing solutions to topology and congestion control problems in sensor networks. As a method of measuring time series complexity and predictability, multiscale entropy (MSE) has been widely applied in many fields. However, sample entropy, which is the fundamental component of MSE, measures the similarity of two subsequences of a time series with either zero or one, but without in-between values, which causes sudden changes of entropy values even if the time series embraces small changes. This problem becomes especially severe when the length of time series is getting short. For solving such the problem, we propose flexible multiscale entropy (FMSE), which introduces a novel similarity function measuring the similarity of two subsequences with full-range values from zero to one, and thus increases the reliability and stability of measuring time series complexity. The proposed method is evaluated on both synthetic and real time series, including white noise, 1/f noise and real vibration signals. The evaluation results demonstrate that FMSE has a significant improvement in reliability and stability of measuring complexity of time series, especially when the length of time series is short, compared to MSE and composite multiscale entropy (CMSE). The proposed method FMSE is capable of improving the performance of time series analysis based topology and traffic congestion control techniques. PMID:28383496

Measuring Complexity and Predictability of Time Series with Flexible Multiscale Entropy for Sensor Networks.

PubMed

Zhou, Renjie; Yang, Chen; Wan, Jian; Zhang, Wei; Guan, Bo; Xiong, Naixue

2017-04-06

Measurement of time series complexity and predictability is sometimes the cornerstone for proposing solutions to topology and congestion control problems in sensor networks. As a method of measuring time series complexity and predictability, multiscale entropy (MSE) has been widely applied in many fields. However, sample entropy, which is the fundamental component of MSE, measures the similarity of two subsequences of a time series with either zero or one, but without in-between values, which causes sudden changes of entropy values even if the time series embraces small changes. This problem becomes especially severe when the length of time series is getting short. For solving such the problem, we propose flexible multiscale entropy (FMSE), which introduces a novel similarity function measuring the similarity of two subsequences with full-range values from zero to one, and thus increases the reliability and stability of measuring time series complexity. The proposed method is evaluated on both synthetic and real time series, including white noise, 1/f noise and real vibration signals. The evaluation results demonstrate that FMSE has a significant improvement in reliability and stability of measuring complexity of time series, especially when the length of time series is short, compared to MSE and composite multiscale entropy (CMSE). The proposed method FMSE is capable of improving the performance of time series analysis based topology and traffic congestion control techniques.

Radiative entropy generation in a gray absorbing, emitting, and scattering planar medium at radiative equilibrium

NASA Astrophysics Data System (ADS)

Sadeghi, Pegah; Safavinejad, Ali

2017-11-01

Radiative entropy generation through a gray absorbing, emitting, and scattering planar medium at radiative equilibrium with diffuse-gray walls is investigated. The radiative transfer equation and radiative entropy generation equations are solved using discrete ordinates method. Components of the radiative entropy generation are considered for two different boundary conditions: two walls are at a prescribed temperature and mixed boundary conditions, which one wall is at a prescribed temperature and the other is at a prescribed heat flux. The effect of wall emissivities, optical thickness, single scattering albedo, and anisotropic-scattering factor on the entropy generation is attentively investigated. The results reveal that entropy generation in the system mainly arises from irreversible radiative transfer at wall with lower temperature. Total entropy generation rate for the system with prescribed temperature at walls remarkably increases as wall emissivity increases; conversely, for system with mixed boundary conditions, total entropy generation rate slightly decreases. Furthermore, as the optical thickness increases, total entropy generation rate remarkably decreases for the system with prescribed temperature at walls; nevertheless, for the system with mixed boundary conditions, total entropy generation rate increases. The variation of single scattering albedo does not considerably affect total entropy generation rate. This parametric analysis demonstrates that the optical thickness and wall emissivities have a significant effect on the entropy generation in the system at radiative equilibrium. Considering the parameters affecting radiative entropy generation significantly, provides an opportunity to optimally design or increase overall performance and efficiency by applying entropy minimization techniques for the systems at radiative equilibrium.

Simultaneous Multi-Scale Diffusion Estimation and Tractography Guided by Entropy Spectrum Pathways

PubMed Central

Galinsky, Vitaly L.; Frank, Lawrence R.

2015-01-01

We have developed a method for the simultaneous estimation of local diffusion and the global fiber tracts based upon the information entropy flow that computes the maximum entropy trajectories between locations and depends upon the global structure of the multi-dimensional and multi-modal diffusion field. Computation of the entropy spectrum pathways requires only solving a simple eigenvector problem for the probability distribution for which efficient numerical routines exist, and a straight forward integration of the probability conservation through ray tracing of the convective modes guided by a global structure of the entropy spectrum coupled with a small scale local diffusion. The intervoxel diffusion is sampled by multi b-shell multi q-angle DWI data expanded in spherical waves. This novel approach to fiber tracking incorporates global information about multiple fiber crossings in every individual voxel and ranks it in the most scientifically rigorous way. This method has potential significance for a wide range of applications, including studies of brain connectivity. PMID:25532167

Computing the Entropy of Kerr-Newman Black Hole Without Brick Walls Method

NASA Astrophysics Data System (ADS)

Zhang, Li-Chun; Wu, Yue-Qin; Li, Huai-Fan; Ren, Zhao

By using the entanglement entropy method, the statistical entropy of the Bose and Fermi fields in a thin film is calculated and the Bekenstein-Hawking entropy of Kerr-Newman black hole is obtained. Here, the Bose and Fermi fields are entangled with the quantum states in Kerr-Newman black hole and are outside of the horizon. The divergence of brick-wall model is avoided without any cutoff by the new equation of state density obtained with the generalized uncertainty principle. The calculation implies that the high density quantum states near the event horizon are strongly correlated with the quantum states in black hole. The black hole entropy is a quantum effect. It is an intrinsic characteristic of space-time. The ultraviolet cutoff in the brick-wall model is unreasonable. The generalized uncertainty principle should be considered in the high energy quantum field near the event horizon. From the calculation, the constant λ introduced in the generalized uncertainty principle is related to polar angle θ in an axisymmetric space-time.

Entropy and convexity for nonlinear partial differential equations

PubMed Central

Ball, John M.; Chen, Gui-Qiang G.

2013-01-01

Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal processes in a thermodynamic system, while the original notion of convexity is for sets and functions in mathematics. Since then, entropy and convexity have become two of the most important concepts in mathematics. In particular, nonlinear methods via entropy and convexity have been playing an increasingly important role in the analysis of nonlinear partial differential equations in recent decades. This opening article of the Theme Issue is intended to provide an introduction to entropy, convexity and related nonlinear methods for the analysis of nonlinear partial differential equations. We also provide a brief discussion about the content and contributions of the papers that make up this Theme Issue. PMID:24249768

A modified belief entropy in Dempster-Shafer framework.

PubMed

Zhou, Deyun; Tang, Yongchuan; Jiang, Wen

2017-01-01

How to quantify the uncertain information in the framework of Dempster-Shafer evidence theory is still an open issue. Quite a few uncertainty measures have been proposed in Dempster-Shafer framework, however, the existing studies mainly focus on the mass function itself, the available information represented by the scale of the frame of discernment (FOD) in the body of evidence is ignored. Without taking full advantage of the information in the body of evidence, the existing methods are somehow not that efficient. In this paper, a modified belief entropy is proposed by considering the scale of FOD and the relative scale of a focal element with respect to FOD. Inspired by Deng entropy, the new belief entropy is consistent with Shannon entropy in the sense of probability consistency. What's more, with less information loss, the new measure can overcome the shortage of some other uncertainty measures. A few numerical examples and a case study are presented to show the efficiency and superiority of the proposed method.

A modified belief entropy in Dempster-Shafer framework

PubMed Central

Zhou, Deyun; Jiang, Wen

2017-01-01

How to quantify the uncertain information in the framework of Dempster-Shafer evidence theory is still an open issue. Quite a few uncertainty measures have been proposed in Dempster-Shafer framework, however, the existing studies mainly focus on the mass function itself, the available information represented by the scale of the frame of discernment (FOD) in the body of evidence is ignored. Without taking full advantage of the information in the body of evidence, the existing methods are somehow not that efficient. In this paper, a modified belief entropy is proposed by considering the scale of FOD and the relative scale of a focal element with respect to FOD. Inspired by Deng entropy, the new belief entropy is consistent with Shannon entropy in the sense of probability consistency. What’s more, with less information loss, the new measure can overcome the shortage of some other uncertainty measures. A few numerical examples and a case study are presented to show the efficiency and superiority of the proposed method. PMID:28481914

Monitoring of Time-Dependent System Profiles by Multiplex Gas Chromatography with Maximum Entropy Demodulation

NASA Technical Reports Server (NTRS)

Becker, Joseph F.; Valentin, Jose

1996-01-01

The maximum entropy technique was successfully applied to the deconvolution of overlapped chromatographic peaks. An algorithm was written in which the chromatogram was represented as a vector of sample concentrations multiplied by a peak shape matrix. Simulation results demonstrated that there is a trade off between the detector noise and peak resolution in the sense that an increase of the noise level reduced the peak separation that could be recovered by the maximum entropy method. Real data originated from a sample storage column was also deconvoluted using maximum entropy. Deconvolution is useful in this type of system because the conservation of time dependent profiles depends on the band spreading processes in the chromatographic column, which might smooth out the finer details in the concentration profile. The method was also applied to the deconvolution of previously interpretted Pioneer Venus chromatograms. It was found in this case that the correct choice of peak shape function was critical to the sensitivity of maximum entropy in the reconstruction of these chromatograms.

A Discrete Constraint for Entropy Conservation and Sound Waves in Cloud-Resolving Modeling

NASA Technical Reports Server (NTRS)

Zeng, Xi-Ping; Tao, Wei-Kuo; Simpson, Joanne

2003-01-01

Ideal cloud-resolving models contain little-accumulative errors. When their domain is so large that synoptic large-scale circulations are accommodated, they can be used for the simulation of the interaction between convective clouds and the large-scale circulations. This paper sets up a framework for the models, using moist entropy as a prognostic variable and employing conservative numerical schemes. The models possess no accumulative errors of thermodynamic variables when they comply with a discrete constraint on entropy conservation and sound waves. Alternatively speaking, the discrete constraint is related to the correct representation of the large-scale convergence and advection of moist entropy. Since air density is involved in entropy conservation and sound waves, the challenge is how to compute sound waves efficiently under the constraint. To address the challenge, a compensation method is introduced on the basis of a reference isothermal atmosphere whose governing equations are solved analytically. Stability analysis and numerical experiments show that the method allows the models to integrate efficiently with a large time step.

Logarithmic entropy of Kehagias-Sfetsos black hole with self-gravitation in asymptotically flat IR modified Hořava gravity

NASA Astrophysics Data System (ADS)

Liu, Molin; Lu, Junwang

2011-05-01

Motivated by recent logarithmic entropy of Hořava-Lifshitz gravity, we investigate Hawking radiation for Kehagias-Sfetsos black hole from tunneling perspective. After considering the effect of self-gravitation, we calculate the emission rate and entropy of quantum tunneling by using Kraus-Parikh-Wilczek method. Meanwhile, both massless and massive particles are considered in this Letter. Interestingly, two types tunneling particles have the same emission rate Γ and entropy Sb whose analytical formulae are Γ=exp[π(rin2-rout2)/2+π/αln rin/rout] and Sb=A/4+π/αln(A/4), respectively. Here, α is the Hořava-Lifshitz field parameter. The results show that the logarithmic entropy of Hořava-Lifshitz gravity could be explained well by the self-gravitation, which is totally different from other methods. The study of this semiclassical tunneling process may shed light on understanding the Hořava-Lifshitz gravity.

Entropy and convexity for nonlinear partial differential equations.

PubMed

Ball, John M; Chen, Gui-Qiang G

2013-12-28

Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal processes in a thermodynamic system, while the original notion of convexity is for sets and functions in mathematics. Since then, entropy and convexity have become two of the most important concepts in mathematics. In particular, nonlinear methods via entropy and convexity have been playing an increasingly important role in the analysis of nonlinear partial differential equations in recent decades. This opening article of the Theme Issue is intended to provide an introduction to entropy, convexity and related nonlinear methods for the analysis of nonlinear partial differential equations. We also provide a brief discussion about the content and contributions of the papers that make up this Theme Issue.

Viscous regularization of the full set of nonequilibrium-diffusion Grey Radiation-Hydrodynamic equations

DOE PAGES

Delchini, Marc O.; Ragusa, Jean C.; Ferguson, Jim

2017-02-17

A viscous regularization technique, based on the local entropy residual, was proposed by Delchini et al. (2015) to stabilize the nonequilibrium-diffusion Grey Radiation-Hydrodynamic equations using an artificial viscosity technique. This viscous regularization is modulated by the local entropy production and is consistent with the entropy minimum principle. However, Delchini et al. (2015) only based their work on the hyperbolic parts of the Grey Radiation-Hydrodynamic equations and thus omitted the relaxation and diffusion terms present in the material energy and radiation energy equations. Here in this paper, we extend the theoretical grounds for the method and derive an entropy minimum principlemore » for the full set of nonequilibrium-diffusion Grey Radiation-Hydrodynamic equations. This further strengthens the applicability of the entropy viscosity method as a stabilization technique for radiation-hydrodynamic shock simulations. Radiative shock calculations using constant and temperature-dependent opacities are compared against semi-analytical reference solutions, and we present a procedure to perform spatial convergence studies of such simulations.« less

Teaching Entropy Analysis in the First-Year High School Course and Beyond

ERIC Educational Resources Information Center

Bindel, Thomas H.

2004-01-01

A new method is presented, which educates and empowers the teachers and assists them in incorporating entropy analysis in their curricula and also provides an entropy-analysis unit that can be used in classrooms. The topics that the teachers can cover depending on the ability of the students and the comfort level of the teacher are included.

Automatic event detection in low SNR microseismic signals based on multi-scale permutation entropy and a support vector machine

NASA Astrophysics Data System (ADS)

Jia, Rui-Sheng; Sun, Hong-Mei; Peng, Yan-Jun; Liang, Yong-Quan; Lu, Xin-Ming

2017-07-01

Microseismic monitoring is an effective means for providing early warning of rock or coal dynamical disasters, and its first step is microseismic event detection, although low SNR microseismic signals often cannot effectively be detected by routine methods. To solve this problem, this paper presents permutation entropy and a support vector machine to detect low SNR microseismic events. First, an extraction method of signal features based on multi-scale permutation entropy is proposed by studying the influence of the scale factor on the signal permutation entropy. Second, the detection model of low SNR microseismic events based on the least squares support vector machine is built by performing a multi-scale permutation entropy calculation for the collected vibration signals, constructing a feature vector set of signals. Finally, a comparative analysis of the microseismic events and noise signals in the experiment proves that the different characteristics of the two can be fully expressed by using multi-scale permutation entropy. The detection model of microseismic events combined with the support vector machine, which has the features of high classification accuracy and fast real-time algorithms, can meet the requirements of online, real-time extractions of microseismic events.

EEG artifacts reduction by multivariate empirical mode decomposition and multiscale entropy for monitoring depth of anaesthesia during surgery.

PubMed

Liu, Quan; Chen, Yi-Feng; Fan, Shou-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

2017-08-01

Electroencephalography (EEG) has been widely utilized to measure the depth of anaesthesia (DOA) during operation. However, the EEG signals are usually contaminated by artifacts which have a consequence on the measured DOA accuracy. In this study, an effective and useful filtering algorithm based on multivariate empirical mode decomposition and multiscale entropy (MSE) is proposed to measure DOA. Mean entropy of MSE is used as an index to find artifacts-free intrinsic mode functions. The effect of different levels of artifacts on the performances of the proposed filtering is analysed using simulated data. Furthermore, 21 patients' EEG signals are collected and analysed using sample entropy to calculate the complexity for monitoring DOA. The correlation coefficients of entropy and bispectral index (BIS) results show 0.14 ± 0.30 and 0.63 ± 0.09 before and after filtering, respectively. Artificial neural network (ANN) model is used for range mapping in order to correlate the measurements with BIS. The ANN method results show strong correlation coefficient (0.75 ± 0.08). The results in this paper verify that entropy values and BIS have a strong correlation for the purpose of DOA monitoring and the proposed filtering method can effectively filter artifacts from EEG signals. The proposed method performs better than the commonly used wavelet denoising method. This study provides a fully adaptive and automated filter for EEG to measure DOA more accuracy and thus reduce risk related to maintenance of anaesthetic agents.

Foreign exchange rate entropy evolution during financial crises

NASA Astrophysics Data System (ADS)

Stosic, Darko; Stosic, Dusan; Ludermir, Teresa; de Oliveira, Wilson; Stosic, Tatijana

2016-05-01

This paper examines the effects of financial crises on foreign exchange (FX) markets, where entropy evolution is measured for different exchange rates, using the time-dependent block entropy method. Empirical results suggest that financial crises are associated with significant increase of exchange rate entropy, reflecting instability in FX market dynamics. In accordance with phenomenological expectations, it is found that FX markets with large liquidity and large trading volume are more inert - they recover quicker from a crisis than markets with small liquidity and small trading volume. Moreover, our numerical analysis shows that periods of economic uncertainty are preceded by periods of low entropy values, which may serve as a tool for anticipating the onset of financial crises.

Entanglement entropy and mutual information production rates in acoustic black holes.

PubMed

Giovanazzi, Stefano

2011-01-07

A method to investigate acoustic Hawking radiation is proposed, where entanglement entropy and mutual information are measured from the fluctuations of the number of particles. The rate of entropy radiated per one-dimensional (1D) channel is given by S=κ/12, where κ is the sound acceleration on the sonic horizon. This entropy production is accompanied by a corresponding formation of mutual information to ensure the overall conservation of information. The predictions are confirmed using an ab initio analytical approach in transonic flows of 1D degenerate ideal Fermi fluids.

Calculation of Five Thermodynamic Molecular Descriptors by Means of a General Computer Algorithm Based on the Group-Additivity Method: Standard Enthalpies of Vaporization, Sublimation and Solvation, and Entropy of Fusion of Ordinary Organic Molecules and Total Phase-Change Entropy of Liquid Crystals.

PubMed

Naef, Rudolf; Acree, William E

2017-06-25

The calculation of the standard enthalpies of vaporization, sublimation and solvation of organic molecules is presented using a common computer algorithm on the basis of a group-additivity method. The same algorithm is also shown to enable the calculation of their entropy of fusion as well as the total phase-change entropy of liquid crystals. The present method is based on the complete breakdown of the molecules into their constituting atoms and their immediate neighbourhood; the respective calculations of the contribution of the atomic groups by means of the Gauss-Seidel fitting method is based on experimental data collected from literature. The feasibility of the calculations for each of the mentioned descriptors was verified by means of a 10-fold cross-validation procedure proving the good to high quality of the predicted values for the three mentioned enthalpies and for the entropy of fusion, whereas the predictive quality for the total phase-change entropy of liquid crystals was poor. The goodness of fit ( Q ²) and the standard deviation (σ) of the cross-validation calculations for the five descriptors was as follows: 0.9641 and 4.56 kJ/mol ( N = 3386 test molecules) for the enthalpy of vaporization, 0.8657 and 11.39 kJ/mol ( N = 1791) for the enthalpy of sublimation, 0.9546 and 4.34 kJ/mol ( N = 373) for the enthalpy of solvation, 0.8727 and 17.93 J/mol/K ( N = 2637) for the entropy of fusion and 0.5804 and 32.79 J/mol/K ( N = 2643) for the total phase-change entropy of liquid crystals. The large discrepancy between the results of the two closely related entropies is discussed in detail. Molecules for which both the standard enthalpies of vaporization and sublimation were calculable, enabled the estimation of their standard enthalpy of fusion by simple subtraction of the former from the latter enthalpy. For 990 of them the experimental enthalpy-of-fusion values are also known, allowing their comparison with predictions, yielding a correlation coefficient R ² of 0.6066.

Germinal center texture entropy as possible indicator of humoral immune response: immunophysiology viewpoint.

PubMed

Pantic, Igor; Pantic, Senka

2012-10-01

In this article, we present the results indicating that spleen germinal center (GC) texture entropy determined by gray-level co-occurrence matrix (GLCM) method is related to humoral immune response. Spleen tissue was obtained from eight outbred male short-haired guinea pigs previously immunized by sheep red blood cells (SRBC). A total of 312 images from 39 germinal centers (156 GC light zone images and 156 GC dark zone images) were acquired and analyzed by GLCM method. Angular second moment, contrast, correlation, entropy, and inverse difference moment were calculated for each image. Humoral immune response to SRBC was measured using T cell-dependent antibody response (TDAR) assay. Statistically highly significant negative correlation was detected between light zone entropy and the number of TDAR plaque-forming cells (r (s) = -0.86, p < 0.01). The entropy decreased as the plaque-forming cells increased and vice versa. A statistically significant negative correlation was also detected between dark zone entropy values and the number of plaque-forming cells (r (s) = -0.69, p < 0.05). Germinal center texture entropy may be a powerful indicator of humoral immune response. This study is one of the first to point out the potential scientific value of GLCM image texture analysis in lymphoid tissue cytoarchitecture evaluation. Lymphoid tissue texture analysis could become an important and affordable addition to the conventional immunophysiology techniques.

Classic maximum entropy recovery of the average joint distribution of apparent FRET efficiency and fluorescence photons for single-molecule burst measurements.

PubMed

DeVore, Matthew S; Gull, Stephen F; Johnson, Carey K

2012-04-05

We describe a method for analysis of single-molecule Förster resonance energy transfer (FRET) burst measurements using classic maximum entropy. Classic maximum entropy determines the Bayesian inference for the joint probability describing the total fluorescence photons and the apparent FRET efficiency. The method was tested with simulated data and then with DNA labeled with fluorescent dyes. The most probable joint distribution can be marginalized to obtain both the overall distribution of fluorescence photons and the apparent FRET efficiency distribution. This method proves to be ideal for determining the distance distribution of FRET-labeled biomolecules, and it successfully predicts the shape of the recovered distributions.

Research on Sustainable Development Level Evaluation of Resource-based Cities Based on Shapely Entropy and Chouqet Integral

NASA Astrophysics Data System (ADS)

Zhao, Hui; Qu, Weilu; Qiu, Weiting

2018-03-01

In order to evaluate sustainable development level of resource-based cities, an evaluation method with Shapely entropy and Choquet integral is proposed. First of all, a systematic index system is constructed, the importance of each attribute is calculated based on the maximum Shapely entropy principle, and then the Choquet integral is introduced to calculate the comprehensive evaluation value of each city from the bottom up, finally apply this method to 10 typical resource-based cities in China. The empirical results show that the evaluation method is scientific and reasonable, which provides theoretical support for the sustainable development path and reform direction of resource-based cities.

Large Eddy Simulation of Entropy Generation in a Turbulent Mixing Layer

NASA Astrophysics Data System (ADS)

Sheikhi, Reza H.; Safari, Mehdi; Hadi, Fatemeh

2013-11-01

Entropy transport equation is considered in large eddy simulation (LES) of turbulent flows. The irreversible entropy generation in this equation provides a more general description of subgrid scale (SGS) dissipation due to heat conduction, mass diffusion and viscosity effects. A new methodology is developed, termed the entropy filtered density function (En-FDF), to account for all individual entropy generation effects in turbulent flows. The En-FDF represents the joint probability density function of entropy, frequency, velocity and scalar fields within the SGS. An exact transport equation is developed for the En-FDF, which is modeled by a system of stochastic differential equations, incorporating the second law of thermodynamics. The modeled En-FDF transport equation is solved by a Lagrangian Monte Carlo method. The methodology is employed to simulate a turbulent mixing layer involving transport of passive scalars and entropy. Various modes of entropy generation are obtained from the En-FDF and analyzed. Predictions are assessed against data generated by direct numerical simulation (DNS). The En-FDF predictions are in good agreements with the DNS data.

Respiration-Averaged CT for Attenuation Correction of PET Images – Impact on PET Texture Features in Non-Small Cell Lung Cancer Patients

PubMed Central

Cheng, Nai-Ming; Fang, Yu-Hua Dean; Tsan, Din-Li

2016-01-01

Purpose We compared attenuation correction of PET images with helical CT (PET/HCT) and respiration-averaged CT (PET/ACT) in patients with non-small-cell lung cancer (NSCLC) with the goal of investigating the impact of respiration-averaged CT on 18F FDG PET texture parameters. Materials and Methods A total of 56 patients were enrolled. Tumors were segmented on pretreatment PET images using the adaptive threshold. Twelve different texture parameters were computed: standard uptake value (SUV) entropy, uniformity, entropy, dissimilarity, homogeneity, coarseness, busyness, contrast, complexity, grey-level nonuniformity, zone-size nonuniformity, and high grey-level large zone emphasis. Comparisons of PET/HCT and PET/ACT were performed using Wilcoxon signed-rank tests, intraclass correlation coefficients, and Bland-Altman analysis. Receiver operating characteristic (ROC) curves as well as univariate and multivariate Cox regression analyses were used to identify the parameters significantly associated with disease-specific survival (DSS). A fixed threshold at 45% of the maximum SUV (T45) was used for validation. Results SUV maximum and total lesion glycolysis (TLG) were significantly higher in PET/ACT. However, texture parameters obtained with PET/ACT and PET/HCT showed a high degree of agreement. The lowest levels of variation between the two modalities were observed for SUV entropy (9.7%) and entropy (9.8%). SUV entropy, entropy, and coarseness from both PET/ACT and PET/HCT were significantly associated with DSS. Validation analyses using T45 confirmed the usefulness of SUV entropy and entropy in both PET/HCT and PET/ACT for the prediction of DSS, but only coarseness from PET/ACT achieved the statistical significance threshold. Conclusions Our results indicate that 1) texture parameters from PET/ACT are clinically useful in the prediction of survival in NSCLC patients and 2) SUV entropy and entropy are robust to attenuation correction methods. PMID:26930211

Perceptual suppression revealed by adaptive multi-scale entropy analysis of local field potential in monkey visual cortex.

PubMed

Hu, Meng; Liang, Hualou

2013-04-01

Generalized flash suppression (GFS), in which a salient visual stimulus can be rendered invisible despite continuous retinal input, provides a rare opportunity to directly study the neural mechanism of visual perception. Previous work based on linear methods, such as spectral analysis, on local field potential (LFP) during GFS has shown that the LFP power at distinctive frequency bands are differentially modulated by perceptual suppression. Yet, the linear method alone may be insufficient for the full assessment of neural dynamic due to the fundamentally nonlinear nature of neural signals. In this study, we set forth to analyze the LFP data collected from multiple visual areas in V1, V2 and V4 of macaque monkeys while performing the GFS task using a nonlinear method - adaptive multi-scale entropy (AME) - to reveal the neural dynamic of perceptual suppression. In addition, we propose a new cross-entropy measure at multiple scales, namely adaptive multi-scale cross-entropy (AMCE), to assess the nonlinear functional connectivity between two cortical areas. We show that: (1) multi-scale entropy exhibits percept-related changes in all three areas, with higher entropy observed during perceptual suppression; (2) the magnitude of the perception-related entropy changes increases systematically over successive hierarchical stages (i.e. from lower areas V1 to V2, up to higher area V4); and (3) cross-entropy between any two cortical areas reveals higher degree of asynchrony or dissimilarity during perceptual suppression, indicating a decreased functional connectivity between cortical areas. These results, taken together, suggest that perceptual suppression is related to a reduced functional connectivity and increased uncertainty of neural responses, and the modulation of perceptual suppression is more effective at higher visual cortical areas. AME is demonstrated to be a useful technique in revealing the underlying dynamic of nonlinear/nonstationary neural signal.

An Information Transmission Measure for the Analysis of Effective Connectivity among Cortical Neurons

PubMed Central

Law, Andrew J.; Sharma, Gaurav; Schieber, Marc H.

2014-01-01

We present a methodology for detecting effective connections between simultaneously recorded neurons using an information transmission measure to identify the presence and direction of information flow from one neuron to another. Using simulated and experimentally-measured data, we evaluate the performance of our proposed method and compare it to the traditional transfer entropy approach. In simulations, our measure of information transmission outperforms transfer entropy in identifying the effective connectivity structure of a neuron ensemble. For experimentally recorded data, where ground truth is unavailable, the proposed method also yields a more plausible connectivity structure than transfer entropy. PMID:21096617

Minimum entropy density method for the time series analysis

NASA Astrophysics Data System (ADS)

Lee, Jeong Won; Park, Joongwoo Brian; Jo, Hang-Hyun; Yang, Jae-Suk; Moon, Hie-Tae

2009-01-01

The entropy density is an intuitive and powerful concept to study the complicated nonlinear processes derived from physical systems. We develop the minimum entropy density method (MEDM) to detect the structure scale of a given time series, which is defined as the scale in which the uncertainty is minimized, hence the pattern is revealed most. The MEDM is applied to the financial time series of Standard and Poor’s 500 index from February 1983 to April 2006. Then the temporal behavior of structure scale is obtained and analyzed in relation to the information delivery time and efficient market hypothesis.

Random versus maximum entropy models of neural population activity

NASA Astrophysics Data System (ADS)

Ferrari, Ulisse; Obuchi, Tomoyuki; Mora, Thierry

2017-04-01

The principle of maximum entropy provides a useful method for inferring statistical mechanics models from observations in correlated systems, and is widely used in a variety of fields where accurate data are available. While the assumptions underlying maximum entropy are intuitive and appealing, its adequacy for describing complex empirical data has been little studied in comparison to alternative approaches. Here, data from the collective spiking activity of retinal neurons is reanalyzed. The accuracy of the maximum entropy distribution constrained by mean firing rates and pairwise correlations is compared to a random ensemble of distributions constrained by the same observables. For most of the tested networks, maximum entropy approximates the true distribution better than the typical or mean distribution from that ensemble. This advantage improves with population size, with groups as small as eight being almost always better described by maximum entropy. Failure of maximum entropy to outperform random models is found to be associated with strong correlations in the population.

Estimating Temporal Causal Interaction between Spike Trains with Permutation and Transfer Entropy

PubMed Central

Li, Zhaohui; Li, Xiaoli

2013-01-01

Estimating the causal interaction between neurons is very important for better understanding the functional connectivity in neuronal networks. We propose a method called normalized permutation transfer entropy (NPTE) to evaluate the temporal causal interaction between spike trains, which quantifies the fraction of ordinal information in a neuron that has presented in another one. The performance of this method is evaluated with the spike trains generated by an Izhikevich’s neuronal model. Results show that the NPTE method can effectively estimate the causal interaction between two neurons without influence of data length. Considering both the precision of time delay estimated and the robustness of information flow estimated against neuronal firing rate, the NPTE method is superior to other information theoretic method including normalized transfer entropy, symbolic transfer entropy and permutation conditional mutual information. To test the performance of NPTE on analyzing simulated biophysically realistic synapses, an Izhikevich’s cortical network that based on the neuronal model is employed. It is found that the NPTE method is able to characterize mutual interactions and identify spurious causality in a network of three neurons exactly. We conclude that the proposed method can obtain more reliable comparison of interactions between different pairs of neurons and is a promising tool to uncover more details on the neural coding. PMID:23940662

Ladar imaging detection of salient map based on PWVD and Rényi entropy

NASA Astrophysics Data System (ADS)

Xu, Yuannan; Zhao, Yuan; Deng, Rong; Dong, Yanbing

2013-10-01

Spatial-frequency information of a given image can be extracted by associating the grey-level spatial data with one of the well-known spatial/spatial-frequency distributions. The Wigner-Ville distribution (WVD) has a good characteristic that the images can be represented in spatial/spatial-frequency domains. For intensity and range images of ladar, through the pseudo Wigner-Ville distribution (PWVD) using one or two dimension window, the statistical property of Rényi entropy is studied. We also analyzed the change of Rényi entropy's statistical property in the ladar intensity and range images when the man-made objects appear. From this foundation, a novel method for generating saliency map based on PWVD and Rényi entropy is proposed. After that, target detection is completed when the saliency map is segmented using a simple and convenient threshold method. For the ladar intensity and range images, experimental results show the proposed method can effectively detect the military vehicles from complex earth background with low false alarm.

Discrimination of isotrigon textures using the Rényi entropy of Allan variances.

PubMed

Gabarda, Salvador; Cristóbal, Gabriel

2008-09-01

We present a computational algorithm for isotrigon texture discrimination. The aim of this method consists in discriminating isotrigon textures against a binary random background. The extension of the method to the problem of multitexture discrimination is considered as well. The method relies on the fact that the information content of time or space-frequency representations of signals, including images, can be readily analyzed by means of generalized entropy measures. In such a scenario, the Rényi entropy appears as an effective tool, given that Rényi measures can be used to provide information about a local neighborhood within an image. Localization is essential for comparing images on a pixel-by-pixel basis. Discrimination is performed through a local Rényi entropy measurement applied on a spatially oriented 1-D pseudo-Wigner distribution (PWD) of the test image. The PWD is normalized so that it may be interpreted as a probability distribution. Prior to the calculation of the texture's PWD, a preprocessing filtering step replaces the original texture with its localized spatially oriented Allan variances. The anisotropic structure of the textures, as revealed by the Allan variances, turns out to be crucial later to attain a high discrimination by the extraction of Rényi entropy measures. The method has been empirically evaluated with a family of isotrigon textures embedded in a binary random background. The extension to the case of multiple isotrigon mosaics has also been considered. Discrimination results are compared with other existing methods.

A Preliminary Investigation of a Fluid-Filled ECG-Triggered Anti-G Suit.

DTIC Science & Technology

1994-02-01

the abdomen, anterior thighs, and calves. In Australia, Dr. F.S. Cotton of Sydney developed a pneumatic anti-G suit using the Royal Australian Air...Acceleration Stress: Model Studies and Preliminary Experiments. IEEE Transactions on Biomedical Engineering, Feb 1985, Vol BME -32(2):158-165. 10 13. Lambert

Developing Black and Minority Ethnic Leaders: The Case for Customized Programmes

ERIC Educational Resources Information Center

Ogunbawo, Dolapo

2012-01-01

The provision of customized black and minority ethnic (BME) leadership courses and programmes is one of the measures being employed to address the under-representation of teachers and school leaders from minority ethnic backgrounds. This strategy has always attracted controversy as opinions have been divided about its value and benefits. Yet there…

Race and Vocational Education and Training in England

ERIC Educational Resources Information Center

Avis, James; Orr, Kevin; Warmington, Paul

2017-01-01

Black and minority ethnic students (BME) are a significant constituency in vocational education and training (VET) and FE in England. Despite this recent research on race and VET has become a marginal concern. Insofar as current VET research addresses social justice, race appears to be a supplementary concern. Although there is a substantial…

Invisible and Hypervisible Academics: The Experiences of Black and Minority Ethnic Teacher Educators

ERIC Educational Resources Information Center

Lander, Vini; Santoro, Ninetta

2017-01-01

This qualitative study investigated the experiences of Black and Minority Ethnic (BME) teacher educators in England and Australia working within the predominantly white space of the academy. Data analysis was informed by a multidimensional theoretical framework drawing on Critical Race Theory, whiteness and Puwar's concept of the Space Invader.…

"Product Placement" to Widening Participation in Psychology: The Case for Culture

ERIC Educational Resources Information Center

Hylton, Patrick L.

2010-01-01

The case is made that psychology, and the British Psychological Society in particular, should make culture in all its guises (multiculturalism, diversity, ethnicities, gender, sexuality, class) part of the core curriculum of undergraduate degrees. It is suggested that this could increase participation by Black and Minority Ethnic groups (BME)…

Exploring Normative Whiteness: Ensuring Inclusive Pedagogic Practice in Undergraduate Fieldwork Teaching and Learning

ERIC Educational Resources Information Center

Hughes, Annie

2016-01-01

Higher education commentators have become concerned about how learning and teaching praxis across the sector may unwittingly advantage White British (WB) compared to Black and Minority Ethnic (BME) students. Adopting critical race theory, this article explores these issues in relation to field teaching in geography and related subjects. It reports…

Music viewed by its entropy content: A novel window for comparative analysis

PubMed Central

Febres, Gerardo; Jaffe, Klaus

2017-01-01

Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a) a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b) a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c) the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the ‘2nd Order Entropy’. Applying these methods to a variety of musical pieces showed how the space of ‘symbolic specific diversity-entropy’ and that of ‘2nd order entropy’ captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning. PMID:29040288

Optimized Kernel Entropy Components.

PubMed

Izquierdo-Verdiguier, Emma; Laparra, Valero; Jenssen, Robert; Gomez-Chova, Luis; Camps-Valls, Gustau

2017-06-01

This brief addresses two main issues of the standard kernel entropy component analysis (KECA) algorithm: the optimization of the kernel decomposition and the optimization of the Gaussian kernel parameter. KECA roughly reduces to a sorting of the importance of kernel eigenvectors by entropy instead of variance, as in the kernel principal components analysis. In this brief, we propose an extension of the KECA method, named optimized KECA (OKECA), that directly extracts the optimal features retaining most of the data entropy by means of compacting the information in very few features (often in just one or two). The proposed method produces features which have higher expressive power. In particular, it is based on the independent component analysis framework, and introduces an extra rotation to the eigen decomposition, which is optimized via gradient-ascent search. This maximum entropy preservation suggests that OKECA features are more efficient than KECA features for density estimation. In addition, a critical issue in both the methods is the selection of the kernel parameter, since it critically affects the resulting performance. Here, we analyze the most common kernel length-scale selection criteria. The results of both the methods are illustrated in different synthetic and real problems. Results show that OKECA returns projections with more expressive power than KECA, the most successful rule for estimating the kernel parameter is based on maximum likelihood, and OKECA is more robust to the selection of the length-scale parameter in kernel density estimation.

Problematizing Social Justice in Health Pedagogy and Youth Sport: Intersectionality of Race, Ethnicity, and Class.

PubMed

Dagkas, Symeon

2016-09-01

Social justice education recognizes the discrepancies in opportunities among disadvantaged groups in society. The purpose of the articles in this special topic on social justice is to (a) provide a critical reflection on issues of social justice within health pedagogy and youth sport of Black and ethnic-minority (BME) young people; (b) provide a framework for the importance of intersectionality research (mainly the intersection of social class, race, and ethnicity) in youth sport and health pedagogy for social justice; and (c) contextualize the complex intersection and interplay of social issues (i.e., race, ethnicity, social classes) and their influence in shaping physical culture among young people with a BME background. The article argues that there are several social identities in any given pedagogical terrain that need to be heard and legitimized to avoid neglect and "othering." This article suggests that a resurgence of interest in theoretical frameworks such as intersectionality can provide an effective platform to legitimize "non-normative bodies" (diverse bodies) in health pedagogy and physical education and sport by voicing positionalities on agency and practice.

Evidence for a Battle Mountain-Eureka crustal fault zone, north-central Nevada, and its relation to Neoproterozoic-Early Paleozoic continental breakup

USGS Publications Warehouse

Grauch, V.J.S.; Rodriguez, B.D.; Bankey, V.; Wooden, J.L.

2003-01-01

Combined evidence from gravity, radiogenic isotope, and magnetotelluric (MT) data indicates a crustal fault zone that coincides with the northwest-trending Battle Mountain-Eureka (BME) mineral trend in north-central Nevada, USA. The BME crustal fault zone likely originated during Neoproterozoic-Early Paleozoic rifting of the continent and had a large influence on subsequent tectonic events, such as emplacement of allochthons and episodic deformation, magmatism, and mineralization throughout the Phanerozoic. MT models show the fault zone is about 10 km wide, 130-km long, and extends from 1 to 5 km below the surface to deep crustal levels. Isotope data and gravity models imply the fault zone separates crust of fundamentally different character. Geophysical evidence for such a long-lived structure, likely inherited from continental breakup, defies conventional wisdom that structures this old have been destroyed by Cenozoic extensional processes. Moreover, the coincidence with the alignment of mineral deposits supports the assertion by many economic geologists that these alignments are indicators of buried regional structures.

Partial knowledge, entropy, and estimation

PubMed Central

MacQueen, James; Marschak, Jacob

1975-01-01

In a growing body of literature, available partial knowledge is used to estimate the prior probability distribution p≡(p1,...,pn) by maximizing entropy H(p)≡-Σpi log pi, subject to constraints on p which express that partial knowledge. The method has been applied to distributions of income, of traffic, of stock-price changes, and of types of brand-article purchases. We shall respond to two justifications given for the method: (α) It is “conservative,” and therefore good, to maximize “uncertainty,” as (uniquely) represented by the entropy parameter. (β) One should apply the mathematics of statistical thermodynamics, which implies that the most probable distribution has highest entropy. Reason (α) is rejected. Reason (β) is valid when “complete ignorance” is defined in a particular way and both the constraint and the estimator's loss function are of certain kinds. PMID:16578733

Entropic criterion for model selection

NASA Astrophysics Data System (ADS)

Tseng, Chih-Yuan

2006-10-01

Model or variable selection is usually achieved through ranking models according to the increasing order of preference. One of methods is applying Kullback-Leibler distance or relative entropy as a selection criterion. Yet that will raise two questions, why use this criterion and are there any other criteria. Besides, conventional approaches require a reference prior, which is usually difficult to get. Following the logic of inductive inference proposed by Caticha [Relative entropy and inductive inference, in: G. Erickson, Y. Zhai (Eds.), Bayesian Inference and Maximum Entropy Methods in Science and Engineering, AIP Conference Proceedings, vol. 707, 2004 (available from arXiv.org/abs/physics/0311093)], we show relative entropy to be a unique criterion, which requires no prior information and can be applied to different fields. We examine this criterion by considering a physical problem, simple fluids, and results are promising.

Entropy of black holes with multiple horizons

NASA Astrophysics Data System (ADS)

He, Yun; Ma, Meng-Sen; Zhao, Ren

2018-05-01

We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and "quintessence horizon" for the black holes surrounded by quintessence). Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

Studies on entanglement entropy for Hubbard model with hole-doping and external magnetic field [rapid communication

NASA Astrophysics Data System (ADS)

Yao, K. L.; Li, Y. C.; Sun, X. Z.; Liu, Q. M.; Qin, Y.; Fu, H. H.; Gao, G. Y.

2005-10-01

By using the density matrix renormalization group (DMRG) method for the one-dimensional (1D) Hubbard model, we have studied the von Neumann entropy of a quantum system, which describes the entanglement of the system block and the rest of the chain. It is found that there is a close relation between the entanglement entropy and properties of the system. The hole-doping can alter the charge charge and spin spin interactions, resulting in charge polarization along the chain. By comparing the results before and after the doping, we find that doping favors increase of the von Neumann entropy and thus also favors the exchange of information along the chain. Furthermore, we calculated the spin and entropy distribution in external magnetic filed. It is confirmed that both the charge charge and the spin spin interactions affect the exchange of information along the chain, making the entanglement entropy redistribute.

Entropy of finite random binary sequences with weak long-range correlations.

PubMed

Melnik, S S; Usatenko, O V

2014-11-01

We study the N-step binary stationary ergodic Markov chain and analyze its differential entropy. Supposing that the correlations are weak we express the conditional probability function of the chain through the pair correlation function and represent the entropy as a functional of the pair correlator. Since the model uses the two-point correlators instead of the block probability, it makes it possible to calculate the entropy of strings at much longer distances than using standard methods. A fluctuation contribution to the entropy due to finiteness of random chains is examined. This contribution can be of the same order as its regular part even at the relatively short lengths of subsequences. A self-similar structure of entropy with respect to the decimation transformations is revealed for some specific forms of the pair correlation function. Application of the theory to the DNA sequence of the R3 chromosome of Drosophila melanogaster is presented.

Entropy of finite random binary sequences with weak long-range correlations

NASA Astrophysics Data System (ADS)

Melnik, S. S.; Usatenko, O. V.

2014-11-01

We study the N -step binary stationary ergodic Markov chain and analyze its differential entropy. Supposing that the correlations are weak we express the conditional probability function of the chain through the pair correlation function and represent the entropy as a functional of the pair correlator. Since the model uses the two-point correlators instead of the block probability, it makes it possible to calculate the entropy of strings at much longer distances than using standard methods. A fluctuation contribution to the entropy due to finiteness of random chains is examined. This contribution can be of the same order as its regular part even at the relatively short lengths of subsequences. A self-similar structure of entropy with respect to the decimation transformations is revealed for some specific forms of the pair correlation function. Application of the theory to the DNA sequence of the R3 chromosome of Drosophila melanogaster is presented.

Separability of a family of one-parameter W and Greenberger-Horne-Zeilinger multiqubit states using the Abe-Rajagopal q-conditional-entropy approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prabhu, R.; Usha Devi, A. R.; Inspire Institute Inc., McLean, Virginia 22101

2007-10-15

We employ conditional Tsallis q entropies to study the separability of symmetric one parameter W and GHZ multiqubit mixed states. The strongest limitation on separability is realized in the limit q{yields}{infinity}, and is found to be much superior to the condition obtained using the von Neumann conditional entropy (q=1 case). Except for the example of two qubit and three qubit symmetric states of GHZ family, the q-conditional entropy method leads to sufficient--but not necessary--conditions on separability.

Discontinuous Galerkin finite element method for the nonlinear hyperbolic problems with entropy-based artificial viscosity stabilization

NASA Astrophysics Data System (ADS)

Zingan, Valentin Nikolaevich

This work develops a discontinuous Galerkin finite element discretization of non- linear hyperbolic conservation equations with efficient and robust high order stabilization built on an entropy-based artificial viscosity approximation. The solutions of equations are represented by elementwise polynomials of an arbitrary degree p > 0 which are continuous within each element but discontinuous on the boundaries. The discretization of equations in time is done by means of high order explicit Runge-Kutta methods identified with respective Butcher tableaux. To stabilize a numerical solution in the vicinity of shock waves and simultaneously preserve the smooth parts from smearing, we add some reasonable amount of artificial viscosity in accordance with the physical principle of entropy production in the interior of shock waves. The viscosity coefficient is proportional to the local size of the residual of an entropy equation and is bounded from above by the first-order artificial viscosity defined by a local wave speed. Since the residual of an entropy equation is supposed to be vanishingly small in smooth regions (of the order of the Local Truncation Error) and arbitrarily large in shocks, the entropy viscosity is almost zero everywhere except the shocks, where it reaches the first-order upper bound. One- and two-dimensional benchmark test cases are presented for nonlinear hyperbolic scalar conservation laws and the system of compressible Euler equations. These tests demonstrate the satisfactory stability properties of the method and optimal convergence rates as well. All numerical solutions to the test problems agree well with the reference solutions found in the literature. We conclude that the new method developed in the present work is a valuable alternative to currently existing techniques of viscous stabilization.

Multidimensional scaling analysis of financial time series based on modified cross-sample entropy methods

NASA Astrophysics Data System (ADS)

He, Jiayi; Shang, Pengjian; Xiong, Hui

2018-06-01

Stocks, as the concrete manifestation of financial time series with plenty of potential information, are often used in the study of financial time series. In this paper, we utilize the stock data to recognize their patterns through out the dissimilarity matrix based on modified cross-sample entropy, then three-dimensional perceptual maps of the results are provided through multidimensional scaling method. Two modified multidimensional scaling methods are proposed in this paper, that is, multidimensional scaling based on Kronecker-delta cross-sample entropy (MDS-KCSE) and multidimensional scaling based on permutation cross-sample entropy (MDS-PCSE). These two methods use Kronecker-delta based cross-sample entropy and permutation based cross-sample entropy to replace the distance or dissimilarity measurement in classical multidimensional scaling (MDS). Multidimensional scaling based on Chebyshev distance (MDSC) is employed to provide a reference for comparisons. Our analysis reveals a clear clustering both in synthetic data and 18 indices from diverse stock markets. It implies that time series generated by the same model are easier to have similar irregularity than others, and the difference in the stock index, which is caused by the country or region and the different financial policies, can reflect the irregularity in the data. In the synthetic data experiments, not only the time series generated by different models can be distinguished, the one generated under different parameters of the same model can also be detected. In the financial data experiment, the stock indices are clearly divided into five groups. Through analysis, we find that they correspond to five regions, respectively, that is, Europe, North America, South America, Asian-Pacific (with the exception of mainland China), mainland China and Russia. The results also demonstrate that MDS-KCSE and MDS-PCSE provide more effective divisions in experiments than MDSC.

Biomass Smoke Exposure Enhances Rhinovirus-Induced Inflammation in Primary Lung Fibroblasts

PubMed Central

Capistrano, Sarah J.; Zakarya, Razia; Chen, Hui; Oliver, Brian G.

2016-01-01

Biomass smoke is one of the major air pollutants and contributors of household air pollution worldwide. More than 3 billion people use biomass fuels for cooking and heating, while other sources of exposure are from the occurrence of bushfires and occupational conditions. Persistent biomass smoke exposure has been associated with acute lower respiratory infection (ALRI) as a major environmental risk factor. Children under the age of five years are the most susceptible in developing severe ALRI, which accounts for 940,000 deaths globally. Around 90% of cases are attributed to viral infections, such as influenza, adenovirus, and rhinovirus. Although several epidemiological studies have generated substantial evidence of the association of biomass smoke and respiratory infections, the underlying mechanism is still unknown. Using an in vitro model, primary human lung fibroblasts were stimulated with biomass smoke extract (BME), specifically investigating hardwood and softwood types, and human rhinovirus-16 for 24 h. Production of pro-inflammatory mediators, such as IL-6 and IL-8, were measured via ELISA. Firstly, we found that hardwood and softwood smoke extract (1%) up-regulate IL-6 and IL-8 release (p ≤ 0.05). In addition, human rhinovirus-16 further increased biomass smoke-induced IL-8 in fibroblasts, in comparison to the two stimulatory agents alone. We also investigated the effect of biomass smoke on viral susceptibility by measuring viral load, and found no significant changes between BME exposed and non-exposed infected fibroblasts. Activated signaling pathways for IL-6 and IL-8 production by BME stimulation were examined using signaling pathway inhibitors. p38 MAPK inhibitor SB239063 significantly attenuated IL-6 and IL-8 release the most (p ≤ 0.05). This study demonstrated that biomass smoke can modulate rhinovirus-induced inflammation during infection, which can alter the severity of the disease. The mechanism by which biomass smoke exposure increases inflammation in the lungs can be targeted and inhibited via p38 MAP kinase pathway. PMID:27571064

Inflammatory bowel disease in young patients: challenges faced by black and minority ethnic communities in the UK.

PubMed

Alexakis, Christopher; Nash, Avril; Lloyd, Michele; Brooks, Fiona; Lindsay, James O; Poullis, Andrew

2015-11-01

There is strong evidence indicating that inflammatory bowel disease (IBD) is increasing among black and minority ethnic (BME) communities. Despite this rise in prevalence, there is a paucity of research relating to ethnicity and IBD outside the USA. Furthermore, the symptoms of IBD are reported to start during childhood or adolescence in 20-25% of people with the condition. It is therefore important that young people's experiences of diagnosis, treatment and living with IBD are fully understood to ensure effective services and information provision. The study reported on in this paper was commissioned by a UK charity (Crohn's and Colitis UK) with the aim of increasing understanding of the specific issues and service needs of young people with IBD from BME communities. Empirical research entailed in-depth semi-structured interviews with 20 young people from BME groups accessed through gastroenterology departments at three collaborating NHS hospitals in England serving ethnically diverse populations. Interviews were carried out from June to December 2010 and sought to capture young people's views with IBD. A thematic analysis of their experiences identified many commonalities with other young people with IBD, such as the problematic route to formal diagnosis and the impact of IBD on education. The young people also experienced tensions between effective self-management strategies and cultural norms and practices relating to food. Moreover, the ability of parents to provide support was hampered for some young people by the absence of culturally competent services that were responsive to the families' communication needs. The findings highlight the need for more culturally appropriate information concerning IBD, and improved responsiveness to young people with IBD within primary care and the education system, as well as culturally competent messaging relating to the specific nature of the condition among the wider South Asian and black communities. © 2015 John Wiley & Sons Ltd.

Structure/function relationships in ligand-based SO{sub 2}/O{sub 2} conversion to sulfate as promoted by nickel and palladium thiolates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darensbourg, M.Y.; Tuntulani, T.; Reibenspies, J.H.

1995-12-06

The dithiolate complex [1,5-bis(mercaptoethyl)-1,5-diazacyclooctane]Pd(II), (bme-daco)Pd{sup II} or Pd-1 whose structure was determined by X-ray crystallography; has been added to a group of metal thiolates which form sulfur-site SO{sub 2} adducts. Exposure of the Pd-1 complex to SO{sub 2} in methanol results in the precipitation of yellow/orange crystalline Pd-1{center_dot}SO{sub 2}. Analogous thiolate-SO{sub 2} adducts based on (bme-daco), Ni-1{center_dot}SO{sub 2}, (Ph{sub 2}PCH{sub 2}CH{sub 2}S){sub 2}Ni{sup II}, Ni-2{center_dot}SO{sub 2}, and (bme*-daco)Ni{sup II}, Ni-1*{center_dot}SO{sub 2}, also precipitate from methanol. To explore the transformation of SO{sub 2} to SO{sub 4}{sup 2-} in these adducts, the following three factors expected to control the sulfate-forming reaction havemore » been examined: (i) the stability of SO{sub 2} adducts; (ii) the oxidizability of the metal thiolate or its tendency to generate disulfide produces on oxidation; and (iii) the ability of the metal thiolates to react with O{sub 2} and produce sulfur-oxygenated products. The studies indicate that the last factor is the most important influence on SO{sub 2} oxygenation. A possible mechanism involves the transient formation of an SO{sub 2}-stabilized sulfperoxide intermediate, which behaves as a nucleophile and further reacts with SO{sub 2} to produce SO{sub 4}{sup 2-}. The use of the aforementioned metal thiolate complexes as catalysts for SO{sub 2} oxygenation in the presence of a sacrificial electron donor has also been explored; simple salts such as NiCl{sub 2} and NiSO{sub 4} are more efficient than the complexes.« less

Utilizing community and voluntary sector partnerships to survey and compare the health outcomes of hard-to- reach groups to the wider community-the EURO- URHIS 2 Hard-to-Reach Project.

PubMed

Harrison, Annie; Robinson, Christine; Williams, Greg; Clough, Gary; Owusu, Melvina Woode; Verma, Arpana

2017-05-01

This article describes the Hard-to-Reach (HtR) Project that was developed to capture health and lifestyle data from groups who are HtR by postal surveys within the larger EURO-URHIS 2 project. By collaborating with partner organizations, data were collected using standard survey tools, allowing for comparison with the wider population. Following a scoping exercise to determine which groups were HtR in Greater Manchester, black and minority ethnic (BME) groups and students were selected. BME groups were surveyed through partnership with Community and Voluntary Sector Organizations (CVSOs). Language barriers were addressed through the recruitment of volunteer interpreters. Students were surveyed by accessing university premises. Fifteen survey visits took place at nine CVSOs and five visits to University facilities. In total, 144 eligible surveys were collected. There were significant differences for both HtR groups, compared with Greater Manchester and the EURO-URHIS 2 mean. Both HtR groups had worse outcomes than both Greater Manchester and EURO-URHIS 2 for psychological problems. In addition, students had worse outcomes for passive smoking, binge drinking, use of cannabis, lack of access to green spaces, less sense of belonging and social cohesion and damp or mildewed homes, and better outcomes for self-perceived health and overweight and obesity. BME had in addition worse outcomes than both Greater Manchester and EURO-URHIS 2 for long-standing restrictive illness. Despite the limitations of this study, the development of this methodology allowed for the collection of comparable data, showing up statistically significant differences between the HtR populations and the wider population which merits further investigation. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Biomass Smoke Exposure Enhances Rhinovirus-Induced Inflammation in Primary Lung Fibroblasts.

PubMed

Capistrano, Sarah J; Zakarya, Razia; Chen, Hui; Oliver, Brian G

2016-08-25

Biomass smoke is one of the major air pollutants and contributors of household air pollution worldwide. More than 3 billion people use biomass fuels for cooking and heating, while other sources of exposure are from the occurrence of bushfires and occupational conditions. Persistent biomass smoke exposure has been associated with acute lower respiratory infection (ALRI) as a major environmental risk factor. Children under the age of five years are the most susceptible in developing severe ALRI, which accounts for 940,000 deaths globally. Around 90% of cases are attributed to viral infections, such as influenza, adenovirus, and rhinovirus. Although several epidemiological studies have generated substantial evidence of the association of biomass smoke and respiratory infections, the underlying mechanism is still unknown. Using an in vitro model, primary human lung fibroblasts were stimulated with biomass smoke extract (BME), specifically investigating hardwood and softwood types, and human rhinovirus-16 for 24 h. Production of pro-inflammatory mediators, such as IL-6 and IL-8, were measured via ELISA. Firstly, we found that hardwood and softwood smoke extract (1%) up-regulate IL-6 and IL-8 release (p ≤ 0.05). In addition, human rhinovirus-16 further increased biomass smoke-induced IL-8 in fibroblasts, in comparison to the two stimulatory agents alone. We also investigated the effect of biomass smoke on viral susceptibility by measuring viral load, and found no significant changes between BME exposed and non-exposed infected fibroblasts. Activated signaling pathways for IL-6 and IL-8 production by BME stimulation were examined using signaling pathway inhibitors. p38 MAPK inhibitor SB239063 significantly attenuated IL-6 and IL-8 release the most (p ≤ 0.05). This study demonstrated that biomass smoke can modulate rhinovirus-induced inflammation during infection, which can alter the severity of the disease. The mechanism by which biomass smoke exposure increases inflammation in the lungs can be targeted and inhibited via p38 MAP kinase pathway.

Association of biopsychosocial factors with degree of slump in sitting posture and self-report of back pain in adolescents: a cross-sectional study.

PubMed

O'Sullivan, Peter B; Smith, Anne J; Beales, Darren J; Straker, Leon M

2011-04-01

Conflicting evidence exists regarding relationships among sitting posture, factors that influence sitting posture, and back pain. This conflicting evidence may partially be due to the presence of multiple and overlapping factors associated with both sitting posture and back pain. The purpose of this study was to determine whether the degree of slump in sitting was associated with sex and other physical, lifestyle, or psychosocial factors. Additionally, the relationship between the report of back pain made worse by sitting and the degree of slump in sitting and other physical, lifestyle, or psychosocial factors was investigated. This was a cross-sectional study. Adolescents (n=1,596) completed questionnaires to determine lifestyle and psychosocial profiles and the experience of back pain. Sagittal sitting posture, body mass index (BMI), and back muscle endurance (BME) were recorded. Standing posture subgroup categorization was determined. Multivariate analysis revealed that the most significant factor associated with the degree of slump in sitting was male sex, followed by non-neutral standing postures, lower perceived self-efficacy, lower BME, greater television use, and higher BMI. Multivariable analysis indicated poorer Child Behaviour Checklist scores were the strongest correlate of report of back pain made worse by sitting, whereas degree of slump in sitting, female sex, and BME were more weakly related. Causality cannot be determined from this cross-sectional study, and 60% of sitting posture variation was not explained by the measured variables. Slump in sitting was associated with physical correlates, as well as sex, lifestyle, and psychosocial factors, highlighting the complex, multidimensional nature of usual sitting posture in adolescents. Additionally, this study demonstrated that a greater degree of slump in sitting was only weakly associated with adolescent back pain made worse by sitting after adjustment for other physical and psychosocial factors.

An adaptable binary entropy coder

NASA Technical Reports Server (NTRS)

Kiely, A.; Klimesh, M.

2001-01-01

We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

Image Analysis Using Quantum Entropy Scale Space and Diffusion Concepts

DTIC Science & Technology

2009-11-01

images using a combination of analytic methods and prototype Matlab and Mathematica programs. We investigated concepts of generalized entropy and...Schmidt strength from quantum logic gate decomposition. This form of entropy gives a measure of the nonlocal content of an entangling logic gate...11 We recall that the Schmidt number is an indicator of entanglement , but not a measure of entanglement . For instance, let us compare

Classic Maximum Entropy Recovery of the Average Joint Distribution of Apparent FRET Efficiency and Fluorescence Photons for Single-molecule Burst Measurements

PubMed Central

DeVore, Matthew S.; Gull, Stephen F.; Johnson, Carey K.

2012-01-01

We describe a method for analysis of single-molecule Förster resonance energy transfer (FRET) burst measurements using classic maximum entropy. Classic maximum entropy determines the Bayesian inference for the joint probability describing the total fluorescence photons and the apparent FRET efficiency. The method was tested with simulated data and then with DNA labeled with fluorescent dyes. The most probable joint distribution can be marginalized to obtain both the overall distribution of fluorescence photons and the apparent FRET efficiency distribution. This method proves to be ideal for determining the distance distribution of FRET-labeled biomolecules, and it successfully predicts the shape of the recovered distributions. PMID:22338694

Out-of-equilibrium protocol for Rényi entropies via the Jarzynski equality.

PubMed

Alba, Vincenzo

2017-06-01

In recent years entanglement measures, such as the von Neumann and the Rényi entropies, provided a unique opportunity to access elusive features of quantum many-body systems. However, extracting entanglement properties analytically, experimentally, or in numerical simulations can be a formidable task. Here, by combining the replica trick and the Jarzynski equality we devise an alternative effective out-of-equilibrium protocol for measuring the equilibrium Rényi entropies. The key idea is to perform a quench in the geometry of the replicas. The Rényi entropies are obtained as the exponential average of the work performed during the quench. We illustrate an application of the method in classical Monte Carlo simulations, although it could be useful in different contexts, such as in quantum Monte Carlo, or experimentally in cold-atom systems. The method is most effective in the quasistatic regime, i.e., for a slow quench. As a benchmark, we compute the Rényi entropies in the Ising universality class in 1+1 dimensions. We find perfect agreement with the well-known conformal field theory predictions.

Identification of breathing cracks in a beam structure with entropy

NASA Astrophysics Data System (ADS)

Wimarshana, Buddhi; Wu, Nan; Wu, Christine

2016-04-01

A cantilever beam with a breathing crack is studied to detect and evaluate the crack using entropy measures. Closed cracks in engineering structures lead to proportional complexities to their vibration responses due to weak bi-linearity imposed by the crack breathing phenomenon. Entropy is a measure of system complexity and has the potential in quantifying the complexity. The weak bi-linearity in vibration signals can be amplified using wavelet transformation to increase the sensitivity of the measurements. A mathematical model of harmonically excited unit length steel cantilever beam with a breathing crack located near the fixed end is established, and an iterative numerical method is applied to generate accurate time domain dynamic responses. The bi-linearity in time domain signals due to the crack breathing are amplified by wavelet transformation first, and then the complexities due to bi-linearity is quantified using sample entropy to detect the possible crack and estimate the crack depth. It is observed that the method is capable of identifying crack depths even at very early stages of 3% with the increase in the entropy values more than 10% compared with the healthy beam. The current study extends the entropy based damage detection of rotary machines to structural analysis and takes a step further in high-sensitivity structural health monitoring by combining wavelet transformation with entropy calculations. The proposed technique can also be applied to other types of structures, such as plates and shells.

Novel Rickettsia raoultii strain isolated and propagated from Austrian Dermacentor reticulatus ticks.

PubMed

Wijnveld, Michiel; Schötta, Anna-Margarita; Pintér, Adriano; Stockinger, Hannes; Stanek, Gerold

2016-11-03

Continuous culture of tick cell lines has proven a valuable asset in isolating and propagating several different vector-borne pathogens, making it possible to study these microorganisms under laboratory conditions and develop serological tests to benefit public health. We describe a method for effective, cost- and labor-efficient isolation and propagation of Rickettsia raoultii using generally available laboratory equipment and Rhipicephalus microplus cells, further demonstrating the usefulness of continuous tick cell lines. R. raoultii is one of the causative agents of tick-borne lymphadenopathy (TIBOLA) and is, together with its vector Dermacentor reticulatus, emerging in novel regions of Europe, giving rise to an increased threat to general public health. Dermacentor reticulatus ticks were collected in the Donau-Auen (Lobau) national park in Vienna, Austria. The hemolymph of ten collected ticks was screened by PCR-reverse line blot for the presence of rickettsial DNA. A single tick tested positive for R. raoultii DNA and was used to infect Rhipicephalus microplus BME/CTVM2 cells. Sixty-five days after infection of the tick-cell line with an extract from a R. raoultii-infected tick, we observed intracellular bacteria in the cultured cells. On the basis of microscopy we suspected that the intracellular bacteria were a species of Rickettsia; this was confirmed by several PCRs targeting different genes. Subsequent sequencing showed 99-100 % identity with R. raoultii. Cryopreservation and resuscitation of R. raoultii was successful. After 28 days identical intracellular bacteria were microscopically observed. R. raoultii was successfully isolated and propagated from D. reticulatus ticks using R. microplus BME/CTVM2 cells. The isolated strain shows significant molecular variation compared to currently known sequences. Furthermore we show for the first time the successful cryopreservation and resuscitation of R. raoultii.

Investigation of Polyurea-Crosslinked Silica Aerogels as a Neuronal Scaffold: A Pilot Study

PubMed Central

Sabri, Firouzeh; Cole, Judith A.; Scarbrough, Michael C.; Leventis, Nicholas

2012-01-01

Background Polymer crosslinked aerogels are an attractive class of materials for future implant applications particularly as a biomaterial for the support of nerve growth. The low density and nano-porous structure of this material combined with large surface area, high mechanical strength, and tunable surface properties, make aerogels materials with a high potential in aiding repair of injuries of the peripheral nervous system. However, the interaction of neurons with aerogels remains to be investigated. Methodology In this work the attachment and growth of neurons on clear polyurea crosslinked silica aerogels (PCSA) coated with: poly-L-lysine, basement membrane extract (BME), and laminin1 was investigated by means of optical and scanning electron microscopy. After comparing the attachment and growth capability of neurons on these different coatings, laminin1 and BME were chosen for nerve cell attachment and growth on PCSA surfaces. The behavior of neurons on treated petri dish surfaces was used as the control and behavior of neurons on treated PCSA discs was compared against it. Conclusions/Significance This study demonstrates that: 1) untreated PCSA surfaces do not support attachment and growth of nerve cells, 2) a thin application of laminin1 layer onto the PCSA discs adhered well to the PCSA surface while also supporting growth and differentiation of neurons as evidenced by the number of processes extended and b3-tubulin expression, 3) three dimensional porous structure of PCSA remains intact after fixing protocols necessary for preservation of biological samples and 4) laminin1 coating proved to be the most effective method for attaching neurons to the desired regions on PCSA discs. This work provides the basis for potential use of PCSA as a biomaterial scaffold for neural regeneration. PMID:22448239

Rényi entropy of the totally asymmetric exclusion process

NASA Astrophysics Data System (ADS)

Wood, Anthony J.; Blythe, Richard A.; Evans, Martin R.

2017-11-01

The Rényi entropy is a generalisation of the Shannon entropy that is sensitive to the fine details of a probability distribution. We present results for the Rényi entropy of the totally asymmetric exclusion process (TASEP). We calculate explicitly an entropy whereby the squares of configuration probabilities are summed, using the matrix product formalism to map the problem to one involving a six direction lattice walk in the upper quarter plane. We derive the generating function across the whole phase diagram, using an obstinate kernel method. This gives the leading behaviour of the Rényi entropy and corrections in all phases of the TASEP. The leading behaviour is given by the result for a Bernoulli measure and we conjecture that this holds for all Rényi entropies. Within the maximal current phase the correction to the leading behaviour is logarithmic in the system size. Finally, we remark upon a special property of equilibrium systems whereby discontinuities in the Rényi entropy arise away from phase transitions, which we refer to as secondary transitions. We find no such secondary transition for this nonequilibrium system, supporting the notion that these are specific to equilibrium cases.

Entropic Imaging of Cataract Lens: An In Vitro Study

PubMed Central

Shung, K. Kirk; Tsui, Po-Hsiang; Fang, Jui; Ma, Hsiang-Yang; Wu, Shuicai; Lin, Chung-Chih

2014-01-01

Phacoemulsification is a common surgical method for treating advanced cataracts. Determining the optimal phacoemulsification energy depends on the hardness of the lens involved. Previous studies have shown that it is possible to evaluate lens hardness via ultrasound parametric imaging based on statistical models that require data to follow a specific distribution. To make the method more system-adaptive, nonmodel-based imaging approach may be necessary in the visualization of lens hardness. This study investigated the feasibility of applying an information theory derived parameter – Shannon entropy from ultrasound backscatter to quantify lens hardness. To determine the physical significance of entropy, we performed computer simulations to investigate the relationship between the signal-to-noise ratio (SNR) based on the Rayleigh distribution and Shannon entropy. Young's modulus was measured in porcine lenses, in which cataracts had been artificially induced by the immersion in formalin solution in vitro. A 35-MHz ultrasound transducer was used to scan the cataract lenses for entropy imaging. The results showed that the entropy is 4.8 when the backscatter data form a Rayleigh distribution corresponding to an SNR of 1.91. The Young's modulus of the lens increased from approximately 8 to 100 kPa when we increased the immersion time from 40 to 160 min (correlation coefficient r = 0.99). Furthermore, the results indicated that entropy imaging seemed to facilitate visualizing different degrees of lens hardening. The mean entropy value increased from 2.7 to 4.0 as the Young's modulus increased from 8 to 100 kPa (r = 0.85), suggesting that entropy imaging may have greater potential than that of conventional statistical parametric imaging in determining the optimal energy to apply during phacoemulsification. PMID:24760103

Using constrained information entropy to detect rare adverse drug reactions from medical forums.

PubMed

Yi Zheng; Chaowang Lan; Hui Peng; Jinyan Li

2016-08-01

Adverse drug reactions (ADRs) detection is critical to avoid malpractices yet challenging due to its uncertainty in pre-marketing review and the underreporting in post-marketing surveillance. To conquer this predicament, social media based ADRs detection methods have been proposed recently. However, existing researches are mostly co-occurrence based methods and face several issues, in particularly, leaving out the rare ADRs and unable to distinguish irrelevant ADRs. In this work, we introduce a constrained information entropy (CIE) method to solve these problems. CIE first recognizes the drug-related adverse reactions using a predefined keyword dictionary and then captures high- and low-frequency (rare) ADRs by information entropy. Extensive experiments on medical forums dataset demonstrate that CIE outperforms the state-of-the-art co-occurrence based methods, especially in rare ADRs detection.

Spatial-dependence recurrence sample entropy

NASA Astrophysics Data System (ADS)

Pham, Tuan D.; Yan, Hong

2018-03-01

Measuring complexity in terms of the predictability of time series is a major area of research in science and engineering, and its applications are spreading throughout many scientific disciplines, where the analysis of physiological signals is perhaps the most widely reported in literature. Sample entropy is a popular measure for quantifying signal irregularity. However, the sample entropy does not take sequential information, which is inherently useful, into its calculation of sample similarity. Here, we develop a method that is based on the mathematical principle of the sample entropy and enables the capture of sequential information of a time series in the context of spatial dependence provided by the binary-level co-occurrence matrix of a recurrence plot. Experimental results on time-series data of the Lorenz system, physiological signals of gait maturation in healthy children, and gait dynamics in Huntington's disease show the potential of the proposed method.

Entropy production of doubly stochastic quantum channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Müller-Hermes, Alexander, E-mail: muellerh@posteo.net; Department of Mathematical Sciences, University of Copenhagen, 2100 Copenhagen; Stilck França, Daniel, E-mail: dsfranca@mytum.de

2016-02-15

We study the entropy increase of quantum systems evolving under primitive, doubly stochastic Markovian noise and thus converging to the maximally mixed state. This entropy increase can be quantified by a logarithmic-Sobolev constant of the Liouvillian generating the noise. We prove a universal lower bound on this constant that stays invariant under taking tensor-powers. Our methods involve a new comparison method to relate logarithmic-Sobolev constants of different Liouvillians and a technique to compute logarithmic-Sobolev inequalities of Liouvillians with eigenvectors forming a projective representation of a finite abelian group. Our bounds improve upon similar results established before and as an applicationmore » we prove an upper bound on continuous-time quantum capacities. In the last part of this work we study entropy production estimates of discrete-time doubly stochastic quantum channels by extending the framework of discrete-time logarithmic-Sobolev inequalities to the quantum case.« less

Text mining by Tsallis entropy

NASA Astrophysics Data System (ADS)

Jamaati, Maryam; Mehri, Ali

2018-01-01

Long-range correlations between the elements of natural languages enable them to convey very complex information. Complex structure of human language, as a manifestation of natural languages, motivates us to apply nonextensive statistical mechanics in text mining. Tsallis entropy appropriately ranks the terms' relevance to document subject, taking advantage of their spatial correlation length. We apply this statistical concept as a new powerful word ranking metric in order to extract keywords of a single document. We carry out an experimental evaluation, which shows capability of the presented method in keyword extraction. We find that, Tsallis entropy has reliable word ranking performance, at the same level of the best previous ranking methods.

A Multi-level Fuzzy Evaluation Method for Smart Distribution Network Based on Entropy Weight

NASA Astrophysics Data System (ADS)

Li, Jianfang; Song, Xiaohui; Gao, Fei; Zhang, Yu

2017-05-01

Smart distribution network is considered as the future trend of distribution network. In order to comprehensive evaluate smart distribution construction level and give guidance to the practice of smart distribution construction, a multi-level fuzzy evaluation method based on entropy weight is proposed. Firstly, focus on both the conventional characteristics of distribution network and new characteristics of smart distribution network such as self-healing and interaction, a multi-level evaluation index system which contains power supply capability, power quality, economy, reliability and interaction is established. Then, a combination weighting method based on Delphi method and entropy weight method is put forward, which take into account not only the importance of the evaluation index in the experts’ subjective view, but also the objective and different information from the index values. Thirdly, a multi-level evaluation method based on fuzzy theory is put forward. Lastly, an example is conducted based on the statistical data of some cites’ distribution network and the evaluation method is proved effective and rational.

Measuring Ambiguity in HLA Typing Methods

PubMed Central

Madbouly, Abeer; Freeman, John; Maiers, Martin

2012-01-01

In hematopoietic stem cell transplantation, donor selection is based primarily on matching donor and patient HLA genes. These genes are highly polymorphic and their typing can result in exact allele assignment at each gene (the resolution at which patients and donors are matched), but it can also result in a set of ambiguous assignments, depending on the typing methodology used. To facilitate rapid identification of matched donors, registries employ statistical algorithms to infer HLA alleles from ambiguous genotypes. Linkage disequilibrium information encapsulated in haplotype frequencies is used to facilitate prediction of the most likely haplotype assignment. An HLA typing with less ambiguity produces fewer high-probability haplotypes and a more reliable prediction. We estimated ambiguity for several HLA typing methods across four continental populations using an information theory-based measure, Shannon's entropy. We used allele and haplotype frequencies to calculate entropy for different sets of 1,000 subjects with simulated HLA typing. Using allele frequencies we calculated an average entropy in Caucasians of 1.65 for serology, 1.06 for allele family level, 0.49 for a 2002-era SSO kit, and 0.076 for single-pass SBT. When using haplotype frequencies in entropy calculations, we found average entropies of 0.72 for serology, 0.73 for allele family level, 0.05 for SSO, and 0.002 for single-pass SBT. Application of haplotype frequencies further reduces HLA typing ambiguity. We also estimated expected confirmatory typing mismatch rates for simulated subjects. In a hypothetical registry with all donors typed using the same method, the entropy values based on haplotype frequencies correspond to confirmatory typing mismatch rates of 1.31% for SSO versus only 0.08% for SBT. Intermediate-resolution single-pass SBT contains the least ambiguity of the methods we evaluated and therefore the most certainty in allele prediction. The presented measure objectively evaluates HLA typing methods and can help define acceptable HLA typing for donor recruitment. PMID:22952712

The maximum entropy method of moments and Bayesian probability theory

NASA Astrophysics Data System (ADS)

Bretthorst, G. Larry

2013-08-01

The problem of density estimation occurs in many disciplines. For example, in MRI it is often necessary to classify the types of tissues in an image. To perform this classification one must first identify the characteristics of the tissues to be classified. These characteristics might be the intensity of a T1 weighted image and in MRI many other types of characteristic weightings (classifiers) may be generated. In a given tissue type there is no single intensity that characterizes the tissue, rather there is a distribution of intensities. Often this distributions can be characterized by a Gaussian, but just as often it is much more complicated. Either way, estimating the distribution of intensities is an inference problem. In the case of a Gaussian distribution, one must estimate the mean and standard deviation. However, in the Non-Gaussian case the shape of the density function itself must be inferred. Three common techniques for estimating density functions are binned histograms [1, 2], kernel density estimation [3, 4], and the maximum entropy method of moments [5, 6]. In the introduction, the maximum entropy method of moments will be reviewed. Some of its problems and conditions under which it fails will be discussed. Then in later sections, the functional form of the maximum entropy method of moments probability distribution will be incorporated into Bayesian probability theory. It will be shown that Bayesian probability theory solves all of the problems with the maximum entropy method of moments. One gets posterior probabilities for the Lagrange multipliers, and, finally, one can put error bars on the resulting estimated density function.

Entanglement entropy in critical phenomena and analog models of quantum gravity

NASA Astrophysics Data System (ADS)

Fursaev, Dmitri V.

2006-06-01

A general geometrical structure of the entanglement entropy for spatial partition of a relativistic QFT system is established by using methods of the effective gravity action and the spectral geometry. A special attention is payed to the subleading terms in the entropy in different dimensions and to behavior in different states. It is conjectured, on the base of relation between the entropy and the action, that in a fundamental theory the ground state entanglement entropy per unit area equals 1/(4GN), where GN is the Newton constant in the low-energy gravity sector of the theory. The conjecture opens a new avenue in analogue gravity models. For instance, in higher-dimensional condensed matter systems, which near a critical point are described by relativistic QFT’s, the entanglement entropy density defines an effective gravitational coupling. By studying the properties of this constant one can get new insights in quantum gravity phenomena, such as the universality of the low-energy physics, the renormalization group behavior of GN, the statistical meaning of the Bekenstein-Hawking entropy.

Entropy stable high order discontinuous Galerkin methods for ideal compressible MHD on structured meshes

NASA Astrophysics Data System (ADS)

Liu, Yong; Shu, Chi-Wang; Zhang, Mengping

2018-02-01

We present a discontinuous Galerkin (DG) scheme with suitable quadrature rules [15] for ideal compressible magnetohydrodynamic (MHD) equations on structural meshes. The semi-discrete scheme is analyzed to be entropy stable by using the symmetrizable version of the equations as introduced by Godunov [32], the entropy stable DG framework with suitable quadrature rules [15], the entropy conservative flux in [14] inside each cell and the entropy dissipative approximate Godunov type numerical flux at cell interfaces to make the scheme entropy stable. The main difficulty in the generalization of the results in [15] is the appearance of the non-conservative "source terms" added in the modified MHD model introduced by Godunov [32], which do not exist in the general hyperbolic system studied in [15]. Special care must be taken to discretize these "source terms" adequately so that the resulting DG scheme satisfies entropy stability. Total variation diminishing / bounded (TVD/TVB) limiters and bound-preserving limiters are applied to control spurious oscillations. We demonstrate the accuracy and robustness of this new scheme on standard MHD examples.

Entropy stable discontinuous interfaces coupling for the three-dimensional compressible Navier-Stokes equations

NASA Astrophysics Data System (ADS)

Parsani, Matteo; Carpenter, Mark H.; Nielsen, Eric J.

2015-06-01

Non-linear entropy stability and a summation-by-parts (SBP) framework are used to derive entropy stable interior interface coupling for the semi-discretized three-dimensional (3D) compressible Navier-Stokes equations. A complete semi-discrete entropy estimate for the interior domain is achieved combining a discontinuous entropy conservative operator of any order [1,2] with an entropy stable coupling condition for the inviscid terms, and a local discontinuous Galerkin (LDG) approach with an interior penalty (IP) procedure for the viscous terms. The viscous penalty contributions scale with the inverse of the Reynolds number (Re) so that for Re → ∞ their contributions vanish and only the entropy stable inviscid interface penalty term is recovered. This paper extends the interface couplings presented [1,2] and provides a simple and automatic way to compute the magnitude of the viscous IP term. The approach presented herein is compatible with any diagonal norm summation-by-parts (SBP) spatial operator, including finite element, finite volume, finite difference schemes and the class of high-order accurate methods which include the large family of discontinuous Galerkin discretizations and flux reconstruction schemes.

Distribution entropy analysis of epileptic EEG signals.

PubMed

Li, Peng; Yan, Chang; Karmakar, Chandan; Liu, Changchun

2015-01-01

It is an open-ended challenge to accurately detect the epileptic seizures through electroencephalogram (EEG) signals. Recently published studies have made elaborate attempts to distinguish between the normal and epileptic EEG signals by advanced nonlinear entropy methods, such as the approximate entropy, sample entropy, fuzzy entropy, and permutation entropy, etc. Most recently, a novel distribution entropy (DistEn) has been reported to have superior performance compared with the conventional entropy methods for especially short length data. We thus aimed, in the present study, to show the potential of DistEn in the analysis of epileptic EEG signals. The publicly-accessible Bonn database which consisted of normal, interictal, and ictal EEG signals was used in this study. Three different measurement protocols were set for better understanding the performance of DistEn, which are: i) calculate the DistEn of a specific EEG signal using the full recording; ii) calculate the DistEn by averaging the results for all its possible non-overlapped 5 second segments; and iii) calculate it by averaging the DistEn values for all the possible non-overlapped segments of 1 second length, respectively. Results for all three protocols indicated a statistically significantly increased DistEn for the ictal class compared with both the normal and interictal classes. Besides, the results obtained under the third protocol, which only used very short segments (1 s) of EEG recordings showed a significantly (p <; 0.05) increased DistEn for the interictal class in compassion with the normal class, whereas both analyses using relatively long EEG signals failed in tracking this difference between them, which may be due to a nonstationarity effect on entropy algorithm. The capability of discriminating between the normal and interictal EEG signals is of great clinical relevance since it may provide helpful tools for the detection of a seizure onset. Therefore, our study suggests that the DistEn analysis of EEG signals is very promising for clinical and even portable EEG monitoring.

An explorative investigation of functional differences in plantar center of pressure of four foot types using sample entropy method.

PubMed

Mei, Zhanyong; Ivanov, Kamen; Zhao, Guoru; Li, Huihui; Wang, Lei

2017-04-01

In the study of biomechanics of different foot types, temporal or spatial parameters derived from plantar pressure are often used. However, there is no comparative study of complexity and regularity of the center of pressure (CoP) during the stance phase among pes valgus, pes cavus, hallux valgus and normal foot. We aim to analyze whether CoP sample entropy characteristics differ among these four foot types. In our experiment participated 40 subjects with normal feet, 40 with pes cavus, 19 with pes valgus and 36 with hallux valgus. A Footscan ® system was used to collect CoP data. We used sample entropy to quantify several parameters of the investigated four foot types. These are the displacement in medial-lateral (M/L) and anterior-posterior (A/P) directions, as well as the vertical ground reaction force of CoP during the stance phase. To fully examine the potential of the sample entropy method for quantification of CoP components, we provide results for two cases: calculating the sample entropy of normalized CoP components, as well as calculating it using the raw data of CoP components. We also explored what are the optimal values of parameters m (the matching length) and r (the tolerance range) when calculating the sample entropy of CoP data obtained during the stance phases. According to statistical results, some factors significantly influenced the sample entropy of CoP components. The sample entropies of non-normalized A/P values for the left foot, as well as for the right foot, were different between the normal foot and pes valgus, and between the normal foot and hallux valgus. The sample entropy of normalized M/L displacement of the right foot was different between the normal foot and pes cavus. The measured variable for A/P and M/L displacements could serve for the study of foot function.

Learning Difficulties and Ethnicity: Updating a Framework for Action

ERIC Educational Resources Information Center

Poxton, Richard

2012-01-01

This update of the Framework for Action highlights the continuing relevance of its message as well as those raised by Valuing People Now. People with learning difficulties and their families from Black and minority ethnic (BME) communities have been highlighted as a priority group by Valuing People since 2001 and remain a priority for better…

A Case Study on a Capsule Robot in the Gastrointestinal Tract to Teach Robot Programming and Navigation

ERIC Educational Resources Information Center

Guo, Yi; Zhang, Shubo; Ritter, Arthur; Man, Hong

2014-01-01

Despite the increasing importance of robotics, there is a significant challenge involved in teaching this to undergraduate students in biomedical engineering (BME) and other related disciplines in which robotics techniques could be readily applied. This paper addresses this challenge through the development and pilot testing of a bio-microrobotics…

Identifying Research Topic Development in Business and Management Education Research Using Legitimation Code Theory

ERIC Educational Resources Information Center

Arbaugh, J. B.; Fornaciari, Charles J.; Hwang, Alvin

2016-01-01

Although the volume of business and management education (BME) research has expanded substantially, concerns remain about the field's legitimacy and its ability to attract new and dedicated scholars. An obstacle that may impede field development is lack of knowledge about influential works and authors to frame topical areas of inquiry and future…

Modeling Exposure to Electromagnetic Fields with Realistic Anatomical Models: The Brooks Finite Difference Time Domain (FDTD)

DTIC Science & Technology

2008-02-01

1996. [15] Gambrill, C.S. DeAngelis M.L., Lu S-T. Error analysis of a thermometric microwave-dosimetry procedure. In: Blank M, editor. Electricity...Transactions on Biomedical Engineering, Vol. BME-31, No. 7, July 1984, 533-536. [18] Lu S-T, DeAngelis ML, Gambrill CS. Ocular microwave thermometric

Location of Disassociated P Wave in an Electrocardiogram

DTIC Science & Technology

1978-12-01

34’A Computerized, Interactive Coronary Care Un-[t--onitoring System," IEEE Transactions on Biomedical Engineering, BME-24: 63-67--anuary 1977). 42...i02 !GO TO iig •:•102 IIP=PP (!K) -(513-ISTEP) ISTEP=i KNPT=LK+5 J=LK+i Fig. 29. Parameters to find the remaining P waves are set. equations modify

Playing the "Race" Card? Black and Minority Ethnic Students' Experiences of Physical Education Teacher Education

ERIC Educational Resources Information Center

Flintoff, Anne

2015-01-01

This paper reports on a study that explored black and minority ethnic (BME) students' experiences of physical education teacher education (PETE) in England. Widening the ethnic diversity of those choosing to enter the teaching profession has been a key policy objective of the Training and Development Agency--the government agency responsible for…

Two-phase thermodynamic model for efficient and accurate absolute entropy of water from molecular dynamics simulations.

PubMed

Lin, Shiang-Tai; Maiti, Prabal K; Goddard, William A

2010-06-24

Presented here is the two-phase thermodynamic (2PT) model for the calculation of energy and entropy of molecular fluids from the trajectory of molecular dynamics (MD) simulations. In this method, the density of state (DoS) functions (including the normal modes of translation, rotation, and intramolecular vibration motions) are determined from the Fourier transform of the corresponding velocity autocorrelation functions. A fluidicity parameter (f), extracted from the thermodynamic state of the system derived from the same MD, is used to partition the translation and rotation modes into a diffusive, gas-like component (with 3Nf degrees of freedom) and a nondiffusive, solid-like component. The thermodynamic properties, including the absolute value of entropy, are then obtained by applying quantum statistics to the solid component and applying hard sphere/rigid rotor thermodynamics to the gas component. The 2PT method produces exact thermodynamic properties of the system in two limiting states: the nondiffusive solid state (where the fluidicity is zero) and the ideal gas state (where the fluidicity becomes unity). We examine the 2PT entropy for various water models (F3C, SPC, SPC/E, TIP3P, and TIP4P-Ew) at ambient conditions and find good agreement with literature results obtained based on other simulation techniques. We also validate the entropy of water in the liquid and vapor phases along the vapor-liquid equilibrium curve from the triple point to the critical point. We show that this method produces converged liquid phase entropy in tens of picoseconds, making it an efficient means for extracting thermodynamic properties from MD simulations.

Entropic benefit of a cross-link in protein association.

PubMed

Zaman, Muhammad H; Berry, R Stephen; Sosnick, Tobin R

2002-08-01

We introduce a method to estimate the loss of configurational entropy upon insertion of a cross-link to a dimeric system. First, a clear distinction is established between the loss of entropy upon tethering and binding, two quantities that are often considered to be equivalent. By comparing the probability distribution of the center-to-center distances for untethered and cross-linked versions, we are able to calculate the loss of translational entropy upon cross-linking. The distribution function for the untethered helices is calculated from the probability that a given helix is closer to its partner than to all other helices, the "Nearest Neighbor" method. This method requires no assumptions about the nature of the solvent, and hence resolves difficulties normally associated with calculations for systems in liquids. Analysis of the restriction of angular freedom upon tethering indicates that the loss of rotational entropy is negligible. The method is applied in the context of the folding of a ten turn helical coiled coil with the tether modeled as a Gaussian chain or a flexible amino acid chain. After correcting for loop closure entropy in the docked state, we estimate the introduction of a six-residue tether in the coiled coil results in an effective concentration of the chain to be about 4 or 100 mM, depending upon whether the helices are denatured or pre-folded prior to their association. Thus, tethering results in significant stabilization for systems with millimolar or stronger dissociation constants. Copyright 2002 Wiley-Liss, Inc.

Estimation of absolute solvent and solvation shell entropies via permutation reduction

NASA Astrophysics Data System (ADS)

Reinhard, Friedemann; Grubmüller, Helmut

2007-01-01

Despite its prominent contribution to the free energy of solvated macromolecules such as proteins or DNA, and although principally contained within molecular dynamics simulations, the entropy of the solvation shell is inaccessible to straightforward application of established entropy estimation methods. The complication is twofold. First, the configurational space density of such systems is too complex for a sufficiently accurate fit. Second, and in contrast to the internal macromolecular dynamics, the configurational space volume explored by the diffusive motion of the solvent molecules is too large to be exhaustively sampled by current simulation techniques. Here, we develop a method to overcome the second problem and to significantly alleviate the first one. We propose to exploit the permutation symmetry of the solvent by transforming the trajectory in a way that renders established estimation methods applicable, such as the quasiharmonic approximation or principal component analysis. Our permutation-reduced approach involves a combinatorial problem, which is solved through its equivalence with the linear assignment problem, for which O(N3) methods exist. From test simulations of dense Lennard-Jones gases, enhanced convergence and improved entropy estimates are obtained. Moreover, our approach renders diffusive systems accessible to improved fit functions.

Classification of Partial Discharge Signals by Combining Adaptive Local Iterative Filtering and Entropy Features

PubMed Central

Morison, Gordon; Boreham, Philip

2018-01-01

Electromagnetic Interference (EMI) is a technique for capturing Partial Discharge (PD) signals in High-Voltage (HV) power plant apparatus. EMI signals can be non-stationary which makes their analysis difficult, particularly for pattern recognition applications. This paper elaborates upon a previously developed software condition-monitoring model for improved EMI events classification based on time-frequency signal decomposition and entropy features. The idea of the proposed method is to map multiple discharge source signals captured by EMI and labelled by experts, including PD, from the time domain to a feature space, which aids in the interpretation of subsequent fault information. Here, instead of using only one permutation entropy measure, a more robust measure, called Dispersion Entropy (DE), is added to the feature vector. Multi-Class Support Vector Machine (MCSVM) methods are utilized for classification of the different discharge sources. Results show an improved classification accuracy compared to previously proposed methods. This yields to a successful development of an expert’s knowledge-based intelligent system. Since this method is demonstrated to be successful with real field data, it brings the benefit of possible real-world application for EMI condition monitoring. PMID:29385030

Understanding the Thermodynamic Properties of the Elastocaloric Effect Through Experimentation and Modelling

NASA Astrophysics Data System (ADS)

Tušek, Jaka; Engelbrecht, Kurt; Mañosa, Lluis; Vives, Eduard; Pryds, Nini

2016-12-01

This paper presents direct and indirect methods for studying the elastocaloric effect (eCE) in shape memory materials and its comparison. The eCE can be characterized by the adiabatic temperature change or the isothermal entropy change (both as a function of applied stress/strain). To get these quantities, the evaluation of the eCE can be done using either direct methods, where one measures (adiabatic) temperature changes or indirect methods where one can measure the stress-strain-temperature characteristics of the materials and from these deduce the adiabatic temperature and isothermal entropy changes. The former can be done using the basic thermodynamic relations, i.e. Maxwell relation and Clausius-Clapeyron equation. This paper further presents basic thermodynamic properties of shape memory materials, such as the adiabatic temperature change, isothermal entropy change and total entropy-temperature diagrams (all as a function of temperature and applied stress/strain) of two groups of materials (Ni-Ti and Cu-Zn-Al alloys) obtained using indirect methods through phenomenological modelling and Maxwell relation. In the last part of the paper, the basic definition of the efficiency of the elastocaloric thermodynamic cycle (coefficient of performance) is defined and discussed.

Measuring an entropy in heavy ion collisions

NASA Astrophysics Data System (ADS)

Bialas, A.; Czyz, W.; Wosiek, J.

1999-03-01

We propose to use the coincidence method of Ma to measure an entropy of the system created in heavy ion collisions. Moreover we estimate, in a simple model, the values of parameters for which the thermodynamical behaviour sets in.

Continuous time wavelet entropy of auditory evoked potentials.

PubMed

Cek, M Emre; Ozgoren, Murat; Savaci, F Acar

2010-01-01

In this paper, the continuous time wavelet entropy (CTWE) of auditory evoked potentials (AEP) has been characterized by evaluating the relative wavelet energies (RWE) in specified EEG frequency bands. Thus, the rapid variations of CTWE due to the auditory stimulation could be detected in post-stimulus time interval. This approach removes the probability of missing the information hidden in short time intervals. The discrete time and continuous time wavelet based wavelet entropy variations were compared on non-target and target AEP data. It was observed that CTWE can also be an alternative method to analyze entropy as a function of time. 2009 Elsevier Ltd. All rights reserved.

Connecting complexity with spectral entropy using the Laplace transformed solution to the fractional diffusion equation

NASA Astrophysics Data System (ADS)

Liang, Yingjie; Chen, Wen; Magin, Richard L.

2016-07-01

Analytical solutions to the fractional diffusion equation are often obtained by using Laplace and Fourier transforms, which conveniently encode the order of the time and the space derivatives (α and β) as non-integer powers of the conjugate transform variables (s, and k) for the spectral and the spatial frequencies, respectively. This study presents a new solution to the fractional diffusion equation obtained using the Laplace transform and expressed as a Fox's H-function. This result clearly illustrates the kinetics of the underlying stochastic process in terms of the Laplace spectral frequency and entropy. The spectral entropy is numerically calculated by using the direct integration method and the adaptive Gauss-Kronrod quadrature algorithm. Here, the properties of spectral entropy are investigated for the cases of sub-diffusion and super-diffusion. We find that the overall spectral entropy decreases with the increasing α and β, and that the normal or Gaussian case with α = 1 and β = 2, has the lowest spectral entropy (i.e., less information is needed to describe the state of a Gaussian process). In addition, as the neighborhood over which the entropy is calculated increases, the spectral entropy decreases, which implies a spatial averaging or coarse graining of the material properties. Consequently, the spectral entropy is shown to provide a new way to characterize the temporal correlation of anomalous diffusion. Future studies should be designed to examine changes of spectral entropy in physical, chemical and biological systems undergoing phase changes, chemical reactions and tissue regeneration.

Multi-Scale Low-Entropy Method for Optimizing the Processing Parameters during Automated Fiber Placement

PubMed Central

Han, Zhenyu; Sun, Shouzheng; Fu, Hongya; Fu, Yunzhong

2017-01-01

Automated fiber placement (AFP) process includes a variety of energy forms and multi-scale effects. This contribution proposes a novel multi-scale low-entropy method aiming at optimizing processing parameters in an AFP process, where multi-scale effect, energy consumption, energy utilization efficiency and mechanical properties of micro-system could be taken into account synthetically. Taking a carbon fiber/epoxy prepreg as an example, mechanical properties of macro–meso–scale are obtained by Finite Element Method (FEM). A multi-scale energy transfer model is then established to input the macroscopic results into the microscopic system as its boundary condition, which can communicate with different scales. Furthermore, microscopic characteristics, mainly micro-scale adsorption energy, diffusion coefficient entropy–enthalpy values, are calculated under different processing parameters based on molecular dynamics method. Low-entropy region is then obtained in terms of the interrelation among entropy–enthalpy values, microscopic mechanical properties (interface adsorbability and matrix fluidity) and processing parameters to guarantee better fluidity, stronger adsorption, lower energy consumption and higher energy quality collaboratively. Finally, nine groups of experiments are carried out to verify the validity of the simulation results. The results show that the low-entropy optimization method can reduce void content effectively, and further improve the mechanical properties of laminates. PMID:28869520

Low-dimensional approximation searching strategy for transfer entropy from non-uniform embedding

PubMed Central

2018-01-01

Transfer entropy from non-uniform embedding is a popular tool for the inference of causal relationships among dynamical subsystems. In this study we present an approach that makes use of low-dimensional conditional mutual information quantities to decompose the original high-dimensional conditional mutual information in the searching procedure of non-uniform embedding for significant variables at different lags. We perform a series of simulation experiments to assess the sensitivity and specificity of our proposed method to demonstrate its advantage compared to previous algorithms. The results provide concrete evidence that low-dimensional approximations can help to improve the statistical accuracy of transfer entropy in multivariate causality analysis and yield a better performance over other methods. The proposed method is especially efficient as the data length grows. PMID:29547669

Optimal quantum networks and one-shot entropies

NASA Astrophysics Data System (ADS)

Chiribella, Giulio; Ebler, Daniel

2016-09-01

We develop a semidefinite programming method for the optimization of quantum networks, including both causal networks and networks with indefinite causal structure. Our method applies to a broad class of performance measures, defined operationally in terms of interative tests set up by a verifier. We show that the optimal performance is equal to a max relative entropy, which quantifies the informativeness of the test. Building on this result, we extend the notion of conditional min-entropy from quantum states to quantum causal networks. The optimization method is illustrated in a number of applications, including the inversion, charge conjugation, and controlization of an unknown unitary dynamics. In the non-causal setting, we show a proof-of-principle application to the maximization of the winning probability in a non-causal quantum game.

A Maximum Entropy Method for Particle Filtering

NASA Astrophysics Data System (ADS)

Eyink, Gregory L.; Kim, Sangil

2006-06-01

Standard ensemble or particle filtering schemes do not properly represent states of low priori probability when the number of available samples is too small, as is often the case in practical applications. We introduce here a set of parametric resampling methods to solve this problem. Motivated by a general H-theorem for relative entropy, we construct parametric models for the filter distributions as maximum-entropy/minimum-information models consistent with moments of the particle ensemble. When the prior distributions are modeled as mixtures of Gaussians, our method naturally generalizes the ensemble Kalman filter to systems with highly non-Gaussian statistics. We apply the new particle filters presented here to two simple test cases: a one-dimensional diffusion process in a double-well potential and the three-dimensional chaotic dynamical system of Lorenz.

An Extension to Deng's Entropy in the Open World Assumption with an Application in Sensor Data Fusion.

PubMed

Tang, Yongchuan; Zhou, Deyun; Chan, Felix T S

2018-06-11

Quantification of uncertain degree in the Dempster-Shafer evidence theory (DST) framework with belief entropy is still an open issue, even a blank field for the open world assumption. Currently, the existed uncertainty measures in the DST framework are limited to the closed world where the frame of discernment (FOD) is assumed to be complete. To address this issue, this paper focuses on extending a belief entropy to the open world by considering the uncertain information represented as the FOD and the nonzero mass function of the empty set simultaneously. An extension to Deng’s entropy in the open world assumption (EDEOW) is proposed as a generalization of the Deng’s entropy and it can be degenerated to the Deng entropy in the closed world wherever necessary. In order to test the reasonability and effectiveness of the extended belief entropy, an EDEOW-based information fusion approach is proposed and applied to sensor data fusion under uncertainty circumstance. The experimental results verify the usefulness and applicability of the extended measure as well as the modified sensor data fusion method. In addition, a few open issues still exist in the current work: the necessary properties for a belief entropy in the open world assumption, whether there exists a belief entropy that satisfies all the existed properties, and what is the most proper fusion frame for sensor data fusion under uncertainty.

Local statistics adaptive entropy coding method for the improvement of H.26L VLC coding

NASA Astrophysics Data System (ADS)

Yoo, Kook-yeol; Kim, Jong D.; Choi, Byung-Sun; Lee, Yung Lyul

2000-05-01

In this paper, we propose an adaptive entropy coding method to improve the VLC coding efficiency of H.26L TML-1 codec. First of all, we will show that the VLC coding presented in TML-1 does not satisfy the sibling property of entropy coding. Then, we will modify the coding method into the local statistics adaptive one to satisfy the property. The proposed method based on the local symbol statistics dynamically changes the mapping relationship between symbol and bit pattern in the VLC table according to sibling property. Note that the codewords in the VLC table of TML-1 codec is not changed. Since this changed mapping relationship also derived in the decoder side by using the decoded symbols, the proposed VLC coding method does not require any overhead information. The simulation results show that the proposed method gives about 30% and 37% reduction in average bit rate for MB type and CBP information, respectively.

Gender-specific heart rate dynamics in severe intrauterine growth-restricted fetuses.

PubMed

Gonçalves, Hernâni; Bernardes, João; Ayres-de-Campos, Diogo

2013-06-01

Management of intrauterine growth restriction (IUGR) remains a major issue in perinatology. The objective of this paper was the assessment of gender-specific fetal heart rate (FHR) dynamics as a diagnostic tool in severe IUGR. FHR was analyzed in the antepartum period in 15 severe IUGR fetuses and 18 controls, matched for gestational age, in relation to fetal gender. Linear and entropy methods, such as mean FHR (mFHR), low (LF), high (HF) and movement frequency (MF), approximate, sample and multiscale entropy. Sensitivities and specificities were estimated using Fisher linear discriminant analysis and the leave-one-out method. Overall, IUGR fetuses presented significantly lower mFHR and entropy compared with controls. However, gender-specific analysis showed that significantly lower mFHR was only evident in IUGR males and lower entropy in IUGR females. In addition, lower LF/(MF+HF) was patent in IUGR females compared with controls, but not in males. Rather high sensitivities and specificities were achieved in the detection of the FHR recordings related with IUGR male fetuses, when gender-specific analysis was performed at gestational ages less than 34 weeks. Severe IUGR fetuses present gender-specific linear and entropy FHR changes, compared with controls, characterized by a significantly lower entropy and sympathetic-vagal balance in females than in males. These findings need to be considered in order to achieve better diagnostic results. Copyright © 2013 Elsevier Ltd. All rights reserved.

Calculation of Cyclodextrin Binding Affinities: Energy, Entropy, and Implications for Drug Design

PubMed Central

Chen, Wei; Chang, Chia-En; Gilson, Michael K.

2004-01-01

The second generation Mining Minima method yields binding affinities accurate to within 0.8 kcal/mol for the associations of α-, β-, and γ-cyclodextrin with benzene, resorcinol, flurbiprofen, naproxen, and nabumetone. These calculations require hours to a day on a commodity computer. The calculations also indicate that the changes in configurational entropy upon binding oppose association by as much as 24 kcal/mol and result primarily from a narrowing of energy wells in the bound versus the free state, rather than from a drop in the number of distinct low-energy conformations on binding. Also, the configurational entropy is found to vary substantially among the bound conformations of a given cyclodextrin-guest complex. This result suggests that the configurational entropy must be accounted for to reliably rank docked conformations in both host-guest and ligand-protein complexes. In close analogy with the common experimental observation of entropy-enthalpy compensation, the computed entropy changes show a near-linear relationship with the changes in mean potential plus solvation energy. PMID:15339804

A Surrogate Technique for Investigating Deterministic Dynamics in Discrete Human Movement.

PubMed

Taylor, Paul G; Small, Michael; Lee, Kwee-Yum; Landeo, Raul; O'Meara, Damien M; Millett, Emma L

2016-10-01

Entropy is an effective tool for investigation of human movement variability. However, before applying entropy, it can be beneficial to employ analyses to confirm that observed data are not solely the result of stochastic processes. This can be achieved by contrasting observed data with that produced using surrogate methods. Unlike continuous movement, no appropriate method has been applied to discrete human movement. This article proposes a novel surrogate method for discrete movement data, outlining the processes for determining its critical values. The proposed technique reliably generated surrogates for discrete joint angle time series, destroying fine-scale dynamics of the observed signal, while maintaining macro structural characteristics. Comparison of entropy estimates indicated observed signals had greater regularity than surrogates and were not only the result of stochastic but also deterministic processes. The proposed surrogate method is both a valid and reliable technique to investigate determinism in other discrete human movement time series.

Conflict management based on belief function entropy in sensor fusion.

PubMed

Yuan, Kaijuan; Xiao, Fuyuan; Fei, Liguo; Kang, Bingyi; Deng, Yong

2016-01-01

Wireless sensor network plays an important role in intelligent navigation. It incorporates a group of sensors to overcome the limitation of single detection system. Dempster-Shafer evidence theory can combine the sensor data of the wireless sensor network by data fusion, which contributes to the improvement of accuracy and reliability of the detection system. However, due to different sources of sensors, there may be conflict among the sensor data under uncertain environment. Thus, this paper proposes a new method combining Deng entropy and evidence distance to address the issue. First, Deng entropy is adopted to measure the uncertain information. Then, evidence distance is applied to measure the conflict degree. The new method can cope with conflict effectually and improve the accuracy and reliability of the detection system. An example is illustrated to show the efficiency of the new method and the result is compared with that of the existing methods.

Beyond maximum entropy: Fractal pixon-based image reconstruction

NASA Technical Reports Server (NTRS)

Puetter, R. C.; Pina, R. K.

1994-01-01

We have developed a new Bayesian image reconstruction method that has been shown to be superior to the best implementations of other methods, including Goodness-of-Fit (e.g. Least-Squares and Lucy-Richardson) and Maximum Entropy (ME). Our new method is based on the concept of the pixon, the fundamental, indivisible unit of picture information. Use of the pixon concept provides an improved image model, resulting in an image prior which is superior to that of standard ME.

Noise reduction algorithm with the soft thresholding based on the Shannon entropy and bone-conduction speech cross- correlation bands.

PubMed

Na, Sung Dae; Wei, Qun; Seong, Ki Woong; Cho, Jin Ho; Kim, Myoung Nam

2018-01-01

The conventional methods of speech enhancement, noise reduction, and voice activity detection are based on the suppression of noise or non-speech components of the target air-conduction signals. However, air-conduced speech is hard to differentiate from babble or white noise signals. To overcome this problem, the proposed algorithm uses the bone-conduction speech signals and soft thresholding based on the Shannon entropy principle and cross-correlation of air- and bone-conduction signals. A new algorithm for speech detection and noise reduction is proposed, which makes use of the Shannon entropy principle and cross-correlation with the bone-conduction speech signals to threshold the wavelet packet coefficients of the noisy speech. The proposed method can be get efficient result by objective quality measure that are PESQ, RMSE, Correlation, SNR. Each threshold is generated by the entropy and cross-correlation approaches in the decomposed bands using the wavelet packet decomposition. As a result, the noise is reduced by the proposed method using the MATLAB simulation. To verify the method feasibility, we compared the air- and bone-conduction speech signals and their spectra by the proposed method. As a result, high performance of the proposed method is confirmed, which makes it quite instrumental to future applications in communication devices, noisy environment, construction, and military operations.

Entropy from State Probabilities: Hydration Entropy of Cations

PubMed Central

2013-01-01

Entropy is an important energetic quantity determining the progression of chemical processes. We propose a new approach to obtain hydration entropy directly from probability density functions in state space. We demonstrate the validity of our approach for a series of cations in aqueous solution. Extensive validation of simulation results was performed. Our approach does not make prior assumptions about the shape of the potential energy landscape and is capable of calculating accurate hydration entropy values. Sampling times in the low nanosecond range are sufficient for the investigated ionic systems. Although the presented strategy is at the moment limited to systems for which a scalar order parameter can be derived, this is not a principal limitation of the method. The strategy presented is applicable to any chemical system where sufficient sampling of conformational space is accessible, for example, by computer simulations. PMID:23651109

Information entropy to measure the spatial and temporal complexity of solute transport in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Li, Weiyao; Huang, Guanhua; Xiong, Yunwu

2016-04-01

The complexity of the spatial structure of porous media, randomness of groundwater recharge and discharge (rainfall, runoff, etc.) has led to groundwater movement complexity, physical and chemical interaction between groundwater and porous media cause solute transport in the medium more complicated. An appropriate method to describe the complexity of features is essential when study on solute transport and conversion in porous media. Information entropy could measure uncertainty and disorder, therefore we attempted to investigate complexity, explore the contact between the information entropy and complexity of solute transport in heterogeneous porous media using information entropy theory. Based on Markov theory, two-dimensional stochastic field of hydraulic conductivity (K) was generated by transition probability. Flow and solute transport model were established under four conditions (instantaneous point source, continuous point source, instantaneous line source and continuous line source). The spatial and temporal complexity of solute transport process was characterized and evaluated using spatial moment and information entropy. Results indicated that the entropy increased as the increase of complexity of solute transport process. For the point source, the one-dimensional entropy of solute concentration increased at first and then decreased along X and Y directions. As time increased, entropy peak value basically unchanged, peak position migrated along the flow direction (X direction) and approximately coincided with the centroid position. With the increase of time, spatial variability and complexity of solute concentration increase, which result in the increases of the second-order spatial moment and the two-dimensional entropy. Information entropy of line source was higher than point source. Solute entropy obtained from continuous input was higher than instantaneous input. Due to the increase of average length of lithoface, media continuity increased, flow and solute transport complexity weakened, and the corresponding information entropy also decreased. Longitudinal macro dispersivity declined slightly at early time then rose. Solute spatial and temporal distribution had significant impacts on the information entropy. Information entropy could reflect the change of solute distribution. Information entropy appears a tool to characterize the spatial and temporal complexity of solute migration and provides a reference for future research.

Application of the new Cross Recurrence Plots to multivariate data

NASA Astrophysics Data System (ADS)

Thiel, M.; Romano, C.; Kurths, J.

2003-04-01

We extend and then apply the method of the new Cross Recurrence Plots (XRPs) to multivariate data. After introducing the new method we carry out an analysis of spatiotemporal ecological data. We compute not only the Rényi entropies and cross entropies by XRP, that allow to draw conclusions about the coupling of the systems, but also find a prediction horizon for intermediate time scales.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozhdestvensky, Yu V

The possibility is studied for obtaining intense cold atomic beams by using the Renyi entropy to optimise the laser cooling process. It is shown in the case of a Gaussian velocity distribution of atoms, the Renyi entropy coincides with the density of particles in the phase space. The optimisation procedure for cooling atoms by resonance optical radiation is described, which is based on the thermodynamic law of increasing the Renyi entropy in time. Our method is compared with the known methods for increasing the laser cooling efficiency such as the tuning of a laser frequency in time and a changemore » of the atomic transition frequency in an inhomogeneous transverse field of a magnetic solenoid. (laser cooling)« less

Entanglement Entropy of the Six-Dimensional Horowitz-Strominger Black Hole

NASA Astrophysics Data System (ADS)

Li, Huai-Fan; Zhang, Sheng-Li; Wu, Yue-Qin; Ren, Zhao

By using the entanglement entropy method, the statistical entropy of the Bose and Fermi fields in a thin film is calculated and the Bekenstein-Hawking entropy of six-dimensional Horowitz-Strominger black hole is obtained. Here, the Bose and Fermi fields are entangled with the quantum states in six-dimensional Horowitz-Strominger black hole and the fields are outside of the horizon. The divergence of brick-wall model is avoided without any cutoff by the new equation of state density obtained with the generalized uncertainty principle. The calculation implies that the high density quantum states near the event horizon are strongly correlated with the quantum states in black hole. The black hole entropy is a quantum effect. It is an intrinsic characteristic of space-time. The ultraviolet cutoff in the brick-wall model is unreasonable. The generalized uncertainty principle should be considered in the high energy quantum field near the event horizon. Using the quantum statistical method, we directly calculate the partition function of the Bose and Fermi fields under the background of the six-dimensional black hole. The difficulty in solving the wave equations of various particles is overcome.

Analysis of crude oil markets with improved multiscale weighted permutation entropy

NASA Astrophysics Data System (ADS)

Niu, Hongli; Wang, Jun; Liu, Cheng

2018-03-01

Entropy measures are recently extensively used to study the complexity property in nonlinear systems. Weighted permutation entropy (WPE) can overcome the ignorance of the amplitude information of time series compared with PE and shows a distinctive ability to extract complexity information from data having abrupt changes in magnitude. Improved (or sometimes called composite) multi-scale (MS) method possesses the advantage of reducing errors and improving the accuracy when applied to evaluate multiscale entropy values of not enough long time series. In this paper, we combine the merits of WPE and improved MS to propose the improved multiscale weighted permutation entropy (IMWPE) method for complexity investigation of a time series. Then it is validated effective through artificial data: white noise and 1 / f noise, and real market data of Brent and Daqing crude oil. Meanwhile, the complexity properties of crude oil markets are explored respectively of return series, volatility series with multiple exponents and EEMD-produced intrinsic mode functions (IMFs) which represent different frequency components of return series. Moreover, the instantaneous amplitude and frequency of Brent and Daqing crude oil are analyzed by the Hilbert transform utilized to each IMF.

Probabilistic modelling of flood events using the entropy copula

NASA Astrophysics Data System (ADS)

Li, Fan; Zheng, Qian

2016-11-01

The estimation of flood frequency is vital for the flood control strategies and hydraulic structure design. Generating synthetic flood events according to statistical properties of observations is one of plausible methods to analyze the flood frequency. Due to the statistical dependence among the flood event variables (i.e. the flood peak, volume and duration), a multidimensional joint probability estimation is required. Recently, the copula method is widely used for multivariable dependent structure construction, however, the copula family should be chosen before application and the choice process is sometimes rather subjective. The entropy copula, a new copula family, employed in this research proposed a way to avoid the relatively subjective process by combining the theories of copula and entropy. The analysis shows the effectiveness of the entropy copula for probabilistic modelling the flood events of two hydrological gauges, and a comparison of accuracy with the popular copulas was made. The Gibbs sampling technique was applied for trivariate flood events simulation in order to mitigate the calculation difficulties of extending to three dimension directly. The simulation results indicate that the entropy copula is a simple and effective copula family for trivariate flood simulation.

Entropy as a Gene-Like Performance Indicator Promoting Thermoelectric Materials.

PubMed

Liu, Ruiheng; Chen, Hongyi; Zhao, Kunpeng; Qin, Yuting; Jiang, Binbin; Zhang, Tiansong; Sha, Gang; Shi, Xun; Uher, Ctirad; Zhang, Wenqing; Chen, Lidong

2017-10-01

High-throughput explorations of novel thermoelectric materials based on the Materials Genome Initiative paradigm only focus on digging into the structure-property space using nonglobal indicators to design materials with tunable electrical and thermal transport properties. As the genomic units, following the biogene tradition, such indicators include localized crystal structural blocks in real space or band degeneracy at certain points in reciprocal space. However, this nonglobal approach does not consider how real materials differentiate from others. Here, this study successfully develops a strategy of using entropy as the global gene-like performance indicator that shows how multicomponent thermoelectric materials with high entropy can be designed via a high-throughput screening method. Optimizing entropy works as an effective guide to greatly improve the thermoelectric performance through either a significantly depressed lattice thermal conductivity down to its theoretical minimum value and/or via enhancing the crystal structure symmetry to yield large Seebeck coefficients. The entropy engineering using multicomponent crystal structures or other possible techniques provides a new avenue for an improvement of the thermoelectric performance beyond the current methods and approaches. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of Renyi Entropies in Multiparticle Production: a Do-List II

NASA Astrophysics Data System (ADS)

Bialas, A.; Czyz, W.; Zalewski, K.

2006-09-01

Recently suggested method of measuring Renyi entropies of multiparticle systems produced in high-energy collisions is presented in the form of a ``do-list'', explaining explicitely how to perform the measurement and suggesting improvements in the treatment of the data.

A comparison of performance of automatic cloud coverage assessment algorithm for Formosat-2 image using clustering-based and spatial thresholding methods

NASA Astrophysics Data System (ADS)

Hsu, Kuo-Hsien

2012-11-01

Formosat-2 image is a kind of high-spatial-resolution (2 meters GSD) remote sensing satellite data, which includes one panchromatic band and four multispectral bands (Blue, Green, Red, near-infrared). An essential sector in the daily processing of received Formosat-2 image is to estimate the cloud statistic of image using Automatic Cloud Coverage Assessment (ACCA) algorithm. The information of cloud statistic of image is subsequently recorded as an important metadata for image product catalog. In this paper, we propose an ACCA method with two consecutive stages: preprocessing and post-processing analysis. For pre-processing analysis, the un-supervised K-means classification, Sobel's method, thresholding method, non-cloudy pixels reexamination, and cross-band filter method are implemented in sequence for cloud statistic determination. For post-processing analysis, Box-Counting fractal method is implemented. In other words, the cloud statistic is firstly determined via pre-processing analysis, the correctness of cloud statistic of image of different spectral band is eventually cross-examined qualitatively and quantitatively via post-processing analysis. The selection of an appropriate thresholding method is very critical to the result of ACCA method. Therefore, in this work, We firstly conduct a series of experiments of the clustering-based and spatial thresholding methods that include Otsu's, Local Entropy(LE), Joint Entropy(JE), Global Entropy(GE), and Global Relative Entropy(GRE) method, for performance comparison. The result shows that Otsu's and GE methods both perform better than others for Formosat-2 image. Additionally, our proposed ACCA method by selecting Otsu's method as the threshoding method has successfully extracted the cloudy pixels of Formosat-2 image for accurate cloud statistic estimation.