Exposure to motor vehicle emissions: An intake fraction approach
Marshall, Julian D.
2002-05-01
Motor vehicles are a significant source of population exposure to air pollution. Focusing on California's South Coast Air Basin as a case study, the author combines ambient monitoring station data with hourly time-activity patterns to determine the population intake of motor vehicle emissions during 1996-1999. Three microenvironments are considered wherein the exposure to motor vehicle emissions is higher than in ambient air: in and near vehicles, inside a building that is near a freeway, and inside a residence with an attached garage. Total motor vehicle emissions are taken from the EMFAC model. The 15 million people in the South Coast inhale 0.0048% of primary, nonreactive compounds emitted into the basin by motor vehicles. Intake of motor vehicle emissions is 46% higher than the average ambient concentration times the average breathing rate, because of microenvironments and because of temporal and spatial correlation among breathing rates, concentrations, and population densities. Intake fraction (iF) summarizes the emissions-to-intake relationship as the ratio of population intake to total emissions. iF is a population level exposure metric that incorporates spatial, temporal, and interindividual variability in exposures. iFs can facilitate the calculation of population exposures by distilling complex emissions-transport-receptor relationships. The author demonstrates this point by predicting the population intake of various primary gaseous emissions from motor vehicles, based on the intake fraction for benzene and carbon monoxide.
Habilomatis, George; Chaloulakou, Archontoula
2015-10-15
Air quality in street canyons is of major importance, since the highest pollution levels are often encountered in these microenvironments. The canyon effect (reduced natural ventilation) makes them "hot spots" for particulate pollution contributing to adverse health effects for the exposed population. In this study we tried to characterize the influence of UFP (ultrafine particle) emissions from traffic on population exposure in an urban street canyon, by applying the intake fraction (iF) approach. One month long measurements of UFP levels have been monitored and used for the need of this study. We applied a three dimensional computational fluid dynamic (CFD) model based on real measurements for the simulation of UFP levels. We used infiltration factors, evaluated on a daily basis for the under study area, to estimate the indoor UFP levels. As a result the intake fraction for the pedestrians, residents and office workers is in the range of (1E-5)-(1E-4). The street canyon is mostly residential justifying partially the higher value of intake fraction for residents (1E-4). The above iF value is on the same order of magnitude with the corresponding one evaluated in a relative street canyon study. The total iF value in this microenvironment is one order of magnitude higher than ours, explained partially by the different use and activities. Two specific applications of iF to assess prioritization among emission sources and environmental justice issues are also examined. We ran a scenario with diesel and gasoline cars and diesel fueled vehicle seems to be a target source to improve overall iF. Our application focus on a small residential area, typical of urban central Athens, in order to evaluate high resolution iF. The significance of source-exposure relationship study in a micro scale is emphasized by recent research. PMID:26047855
Intake fractions of industrial air pollutants in China: estimation and application.
Wang, Shuxiao; Hao, Jiming; Ho, Mun S; Li, Ji; Lu, Yongqi
2006-02-01
Intake fractions, an emissions-intake relationship for primary pollutants, are defined and are estimated in order to make simple estimates of health damages from air pollution. The sulfur dioxide (SO2) and total suspended particles (TSP) intake fractions for five cities of China are estimated for the four main polluting industries-electric power generation, mineral (mostly cement) products industry, chemical process industry and metallurgical industry (mainly iron and steel smelting). The Industrial Source Complex Long Term (ISTLT3) model is used to simulate the spatial distribution of incremental ambient concentrations due to emissions from a large sample of site-specific sources. Detailed population distribution information is used for each city. The average intake fractions within 50 km of these sources are 4.4x10(-6) for TSP, and 4.2x10(-6) for SO2, with standard deviations of 8.15x10(-6) and 9.16x10(-6), respectively. They vary over a wide range, from 10(-7) to 10(-5). Although the electric power generation has been the focus of much of the air pollution research in China, our results show that it has the lowest average intake fraction for a local range among the four industries, which highlights the importance of pollutant emissions from other industrial sources. Sensitivity analyses show how the intake fractions are affected by the source and pollutant characteristics, the most important parameter being the size of the domain. However, the intake fraction estimates are robust enough to be useful for evaluating the local impacts on human health of primary SO2 and TSP emissions. An application of intake fractions is given to demonstrate how this approach provides a rapid population risk estimate if the dose-response function is linear without threshold, and hence can help in prioritizing pollution control efforts. PMID:16398989
Application of intake fraction to population exposure estimates in Hunan Province of China.
Li, Ji; Hao, Jiming
2003-06-01
This article developed a new method, based on the concept of "intake fraction", to assess population exposure to primary and secondary fine particle matters from site-specific sources. This method was illustrated by a set of 17 power plants (totally 24 stacks) in Hunan Province of China. The CALPUFF long-range atmospheric dispersion model was used to simulate ambient concentrations of fine particles, and the GIS technology was used to generate a population distribution database from county-level population statistical data. An integrated computer program package was developed to carry out numerical integration of dispersion results over the population data, and produce intake fractions. The resulting average intake fractions within 500 km were 9.73 x 10(-6), 2.39 x 10(-6), and 2.47 x 10(-6) for primary fine particles, sulfate and nitrate respectively. Regression analyses were performed to explore the relationships between intake fractions and potential variables. Results showed that the stack height and aggregate populations could be used to predict intake fractions of fine particles. R2 of the regression equations were 0.83, 0.64, and 0.74 for primary fine particles, sulfate and nitrate respectively. Iso-intake fractions presenting geographical distributions of intake fractions in Hunan Province were mapped, showing a factor of about 2 between the highest values in the northeast and the lowest in the southwest of Hunan Province. PMID:12774907
Intake fraction for the indoor environment: a tool for prioritizing indoor chemical sources.
Shin, Hyeong-Moo; McKone, Thomas E; Bennett, Deborah H
2012-09-18
Reliable exposure-based chemical characterization tools are needed to evaluate and prioritize in a rapid and efficient manner the more than tens of thousands of chemicals in current use. This study applies intake fraction (iF), the integrated incremental intake of a chemical per unit of emission, for a suite of indoor released compounds. A fugacity-based indoor mass-balance model was used to simulate the fate and transport of chemicals for three release scenarios: direct emissions to room air and surface applications to carpet and vinyl. Exposure through inhalation, dermal uptake, and nondietary ingestion was estimated. To compute iF, cumulative intake was summed from all exposure pathways for 20 years based on a scenario with two adults and a 1-year-old child who ages through the simulation. Overall iFs vary by application modes: air release (3.1 × 10(-3) to 6.3 × 10(-3)), carpet application (3.8 × 10(-5) to 6.2 × 10(-3)), and vinyl application (9.0 × 10(-5) to 1.8 × 10(-2)). These iF values serve as initial estimates that offer important insights on variations among chemicals and the potential relative contribution of each pathway over a suite of compounds. The approach from this study is intended for exposure-based prioritization of chemicals released inside homes. PMID:22920860
Defining Product Intake Fraction to Quantify and Compare Exposure to Consumer Products.
Jolliet, Olivier; Ernstoff, Alexi S; Csiszar, Susan A; Fantke, Peter
2015-08-01
There is a growing consciousness that exposure studies need to better cover near-field exposure associated with products use. To consistently and quantitatively compare human exposure to chemicals in consumer products, we introduce the concept of product intake fraction, as the fraction of a chemical within a product that is eventually taken in by the human population. This metric enables consistent comparison of exposures during consumer product use for different product-chemical combinations, exposure duration, exposure routes and pathways and for other life cycle stages. We present example applications of the product intake fraction concept, for two chemicals in two personal care products and two chemicals encapsulated in two articles, showing how intakes of these chemicals can primarily occur during product use. We demonstrate the utility of the product intake fraction and its application modalities within life cycle assessment and risk assessment contexts. The product intake fraction helps to provide a clear interface between the life cycle inventory and impact assessment phases, to identify best suited sentinel products and to calculate overall exposure to chemicals in consumer products, or back-calculate maximum allowable concentrations of substances inside products. PMID:26102159
3. APPROACH TO THE ACCESS BRIDGE AND INTAKE PIER, LOOKING ...
3. APPROACH TO THE ACCESS BRIDGE AND INTAKE PIER, LOOKING SOUTHWEST. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA
11. DETAIL VIEW OF APPROACH TO INTAKE PIER FROM ACCESS ...
11. DETAIL VIEW OF APPROACH TO INTAKE PIER FROM ACCESS BRIDGE, SHOWING DOOR TO INTERIOR GATE OPERATOR ROOM, LOOKING WEST. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA
Human intake fraction of toxic pollutants: a model comparison between caltox and uses-lca
Huijbregts, Mark A.J.; Geelen, Loes M.J.; Hertwich, Edgar G.; McKone, Thomas E.; van de Meent, Dik
2004-01-06
In Life Cycle Assessment and Comparative Risk Assessment potential human exposure to toxic pollutants can be expressed as the human intake fraction (iF), representing the fraction of the quantity emitted that enters the human population. To assess model uncertainty in the human intake fraction, ingestion and inhalation iFs of 367 substances emitted to air and freshwater were calculated with two commonly applied multi-media fate and exposure models, CalTOX and USES-LCA. Comparison of the model outcomes reveal that uncertainty in the ingestion iFs was up to a factor of 70. The uncertainty in the inhalation iFs was up to a factor of 865,000. The comparison showed that relatively few model differences account for the uncertainties found. An optimal model structure in the calculation of human intake fractions can be achieved by including (1) rain and no-rain scenarios, (2) a continental sea water compartment, (3) drinking water purification, (4) pH-correction of chemical properties, and (5) aerosol-associated deposition on plants. Finally, vertical stratification of the soil compartment combined with a chemical-dependent soil depth may be considered in future intake fraction calculations.
Estimation of primary and secondary particulate matter intake fractions for power plants in Georgia.
Levy, Jonathan I; Wilson, Andrew M; Evans, John S; Spengler, John D
2003-12-15
Air pollution benefit-cost analyses depend on dispersion models to predict population exposures to pollutants, but it is difficult to determine the reasonableness of the model estimates. This is in part because validation with field measurements is not feasible for marginal concentration changes and because few models can capture the necessary spatial and temporal domains with adequate sophistication. In this study, we use the concept of an intake fraction (the fraction of a pollutant or its precursor emitted that is eventually inhaled) to provide insight about population exposures and model performance. We apply CALPUFF, a regional-scale dispersion model common in health benefits assessments, to seven power plants in northern Georgia, considering both direct emissions of fine particulate matter (PM2.5) and secondarily formed ammonium sulfate and ammonium nitrate particles over a domain within 500 km of Atlanta. We estimate emission-weighted average intake fractions of 6 x 10(-7) for primary PM2.5, 2 x 10(-7) for ammonium sulfate from SO2, and 6 x 10(-8) for ammonium nitrate from NOx, with no effect of SO2 on ammonium nitrate. To provide insight about model strengths and limitations, we compare our findings with those from a frequently applied source-receptor (S-R) matrix. Using S-R matrix over an identical domain, the corresponding intake fractions are 5 x 10(-7), 2 x 10(-7), 3 x 10(-8), and -2 x 10(-8), respectively, with the values approximately doubling if the domain is expanded to cover the continental United States. Evaluation of model assumptions and comparison of past intake fraction estimates using these two models illustrates the importance of assumptions about the relative concentrations of ammonia, sulfate, and nitrate, which significantly influences ammonium nitrate intake fractions. These findings provide a framework for improved understanding of the factors that influence population exposures to particulate matter. PMID:14717160
Bolster, Douglas R; Pikosky, Matthew A; Gaine, P Courtney; Martin, William; Wolfe, Robert R; Tipton, Kevin D; Maclean, David; Maresh, Carl M; Rodriguez, Nancy R
2005-10-01
This investigation evaluated the physiological impact of different dietary protein intakes on skeletal muscle protein synthesis postexercise in endurance runners. Five endurance-trained, male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP)-, moderate (1.8 g/kg; MP)-, or high (3.6 g/kg; HP)-protein diet for 4 wk. Diets were designed to be eucaloric with carbohydrate, fat, and protein approximating 60, 30, and 10%; 55, 30, and 15%; and 40, 30, and 30% for LP, MP, and HP, respectively. Substrate oxidation was assessed via indirect calorimetry at 3 wk of the dietary interventions. Mixed-muscle protein fractional synthetic rate (FSR) was measured after an endurance run (75 min at 70% V(O2 peak)) using a primed, continuous infusion of [(2)H(5)]phenylalanine. Protein oxidation increased with increasing protein intake, with each trial being significantly different from the other (P < 0.01). FSR after exercise was significantly greater for LP (0.083%/h) and MP (0.078%/h) than for HP (0.052%/h; P < 0.05). There was no difference in FSR between LP and MP. This is the first investigation to establish that habitual dietary protein intake in humans modulates skeletal muscle protein synthesis after an endurance exercise bout. Future studies directed at mechanisms by which level of protein intake influences skeletal muscle turnover are needed. PMID:15914508
A novel approach for food intake detection using electroglottography
Farooq, Muhammad; Fontana, Juan M; Sazonov, Edward
2014-01-01
Many methods for monitoring diet and food intake rely on subjects self-reporting their daily intake. These methods are subjective, potentially inaccurate and need to be replaced by more accurate and objective methods. This paper presents a novel approach that uses an Electroglottograph (EGG) device for an objective and automatic detection of food intake. Thirty subjects participated in a 4-visit experiment involving the consumption of meals with self-selected content. Variations in the electrical impedance across the larynx caused by the passage of food during swallowing were captured by the EGG device. To compare performance of the proposed method with a well-established acoustical method, a throat microphone was used for monitoring swallowing sounds. Both signals were segmented into non-overlapping epochs of 30 s and processed to extract wavelet features. Subject-independent classifiers were trained using Artificial Neural Networks, to identify periods of food intake from the wavelet features. Results from leave-one-out cross-validation showed an average per-epoch classification accuracy of 90.1% for the EGG-based method and 83.1% for the acoustic-based method, demonstrating the feasibility of using an EGG for food intake detection. PMID:24671094
New approaches in the derivation of acceptable daily intake (ADI)
Dourson, M.L.
1986-01-01
Current methods for estimating human health risks from exposure to threshold-acting toxicants in water or food, such as those established by the U.S. EPA, the FDA, the NAS, the WHO and the FAO, consider only chronic or lifetime exposure to individual chemicals. These methods generally estimate a single, constant daily intake rate which is low enough to be considered safe or acceptable. The intake rate is termed the acceptable daily intake (ADI). Two problems with the approach have been recognized. The first problem is that the method does not readily account for the number of animals used to determine the appropriate 'no-observed-effect-level' (NOEL). The second problem with the current approach is that the slope of the dose-response curve of the critical toxic effect is generally ignored in estimating the ADI. The report illustrates both a revised approach to estimate ADIs with all toxicity data which includes methods for partial lifetime assessment, and novel methods for ADI estimation with quantal or continuous toxicity data. The latter method addresses to a degree the common problems with the current approach.
Developing intake fraction estimates with limited data: Comparison of methods in Mexico City
NASA Astrophysics Data System (ADS)
Stevens, Gretchen; de Foy, Benjamin; West, J. Jason; Levy, Jonathan I.
In order to estimate the health benefits of reducing mobile source emissions, analysts typically use detailed atmospheric models to estimate the change in population exposure that results from a given change in emissions. However, this may not be feasible in settings where data are limited or policy decisions are needed in the short term. Intake fraction (iF), defined as the fraction of emissions of a pollutant or its precursor that is inhaled by the population, is a metric that can be used to compare exposure assessment methods in a health benefits analysis context. To clarify the utility of rapid-assessment methods, we calculate particulate matter iFs for the Mexico City Metropolitan Area using five methods, some more resource intensive than others. First, we create two simple box models to describe dispersion of primary fine particulate matter (PM 2.5) in the Mexico City basin. Second, we extrapolate iFs for primary PM 2.5, ammonium sulfate, and ammonium nitrate from US values using a regression model. Third, we calculate iFs by assuming a linear relationship between emissions and population-weighted concentrations of primary PM 2.5, ammonium nitrate, and ammonium sulfate (a particle composition method). Finally, we estimate PM iFs from detailed atmospheric dispersion and chemistry models run for only a short period of time. Intake fractions vary by up to a factor of five, from 23 to 120 per million for primary PM 2.5. Estimates of 60, 7, and 0.7 per million for primary PM, secondary ammonium sulfate, and secondary ammonium nitrate, respectively, represent credible central estimates, with an approximate factor of two uncertainty surrounding each estimate. Our results emphasize that multiple rapid-assessment methods can provide meaningful estimates of iFs in resource-limited environments, and that formal uncertainty analysis, with special attention to model biases and uncertainty, would be important for health benefits analyses.
NASA Astrophysics Data System (ADS)
Heath, Garvin A.; Granvold, Patrick W.; Hoats, Abigail S.; W Nazaroff, William
Small-scale, distributed electricity generation (DG) technologies have been promoted for their many benefits as compared to the traditional paradigm of large, centralized power plants. To evaluate the implications for human inhalation exposure resulting from a shift toward DG, we combined Gaussian plume modeling and a GIS-based inhalation exposure assessment of existing and hypothetical power-generation facilities in California. Twenty-five existing central stations (CSs) were analyzed and compared with hypothetical DG technologies deployed in the downtown areas of the 11 most populous cities in California. The intake fraction (iF) for primary pollutants was computed for populations living within 100 km of each source, using meteorological conditions typical of the long-term observational record and population, lifetime-average breathing rates. The iF (a dimensionless term representing the proportion of pollutant mass emitted by a source that is eventually inhaled) concisely expresses the source-to-intake relationship, is independent of the emissions characteristics of the plants assessed, and normalizes for the large scale differences between the two paradigms of electricity generation. The median iF for nonreactive primary pollutants emitted from the 25 CSs is 0.8 per million compared to 16 per million for the 11 DG units. The difference is partly attributable to the closer proximity of DG sources to densely populated areas as compared to typical CS facilities. In addition, the short stacks of DG sources emphasize near-source population exposure more than traditional CSs, and increase exposures during periods of low wind speed, low mixing height and stable atmospheric conditions. Strategies that could reduce the potential increase in air pollutant intake from DG include maximally utilizing waste heat in combined heat and power operations, increasing the release height of DG effluents and deploying DG technologies that do not emit air pollutants.
Intake fraction of PM2.5 and NOX from vehicle emissions in Beijing based on personal exposure data
NASA Astrophysics Data System (ADS)
Du, Xuan; Wu, Ye; Fu, Lixin; Wang, Shuxiao; Zhang, Shaojun; Hao, Jiming
2012-09-01
The intake fraction (iF) is the portion of attributable population intake of a source emissions, and is used to link pollutant emissions and population exposure. This study is the first work that reported individual intake fraction of PM2.5 and NOX from vehicle emissions based on personal exposure data in China. We employed PM2.5 and NOX measurement data from 24-h personal exposure sampling and concentration monitoring in traffic environments in the urban area of Beijing to estimate the individual intake fraction (iFi). iFi distributions are presented in microenvironments (traffic, work, home) for adults and children. The individual results are used to calculate the intake fraction for the children group and the adults group in the urban area of Beijing. The iF of PM2.5 for the whole population of these two groups in Beijing is 153 per million, which is significantly higher than those estimates in the United States (1-50 per million) and Mexico (23-120 per million). The iF of NOX is 70 per million, among which the intake in the traffic micro-environment ranks first compared to the iF in the home and office due to a high accumulation of NOX concentration in vehicles. PM2.5 and NOX intake fraction values from vehicle emissions in this study are from at least several times to one order of magnitude higher than those from other industry sources in China. This strongly suggests the health risk from vehicle emissions is significantly higher. Therefore, to protect human health, especially for the large number of people living in the cities of China, controlling vehicle emissions should be the highest priority.
Multiplication with Fractions: A Constructivist Approach.
ERIC Educational Resources Information Center
Kamii, Constance; Warrington, Mary Ann
1997-01-01
Describes a method for teaching multiplication of fractions based on Piaget's constructivism. Instead of teaching the algorithm of multiplying the numerators and denominators, students are presented with many problems and ask to invent their own ways of solving them. (DDR)
Matrix approach to discrete fractional calculus II: Partial fractional differential equations
NASA Astrophysics Data System (ADS)
Podlubny, Igor; Chechkin, Aleksei; Skovranek, Tomas; Chen, YangQuan; Vinagre Jara, Blas M.
2009-05-01
A new method that enables easy and convenient discretization of partial differential equations with derivatives of arbitrary real order (so-called fractional derivatives) and delays is presented and illustrated on numerical solution of various types of fractional diffusion equation. The suggested method is the development of Podlubny's matrix approach [I. Podlubny, Matrix approach to discrete fractional calculus, Fractional Calculus and Applied Analysis 3 (4) (2000) 359-386]. Four examples of numerical solution of fractional diffusion equation with various combinations of time-/space-fractional derivatives (integer/integer, fractional/integer, integer/fractional, and fractional/fractional) with respect to time and to the spatial variable are provided in order to illustrate how simple and general is the suggested approach. The fifth example illustrates that the method can be equally simply used for fractional differential equations with delays. A set of MATLAB routines for the implementation of the method as well as sample code used to solve the examples have been developed.
Intake fraction variability between air pollution emission sources inside an urban area.
Tainio, Marko; Holnicki, Piotr; Loh, Miranda M; Nahorski, Zbigniew
2014-11-01
The cost-effective mitigation of adverse health effects caused by air pollution requires information on the contribution of different emission sources to exposure. In urban areas the exposure potential of different sources may vary significantly depending on emission height, population density, and other factors. In this study, we quantified this intraurban variability by predicting intake fraction (iF) for 3,066 emission sources in Warsaw, Poland. iF describes the fraction of the pollutant that is inhaled by people in the study area. We considered the following seven pollutants: particulate matter (PM), nitrogen oxides (NOx), sulfur dioxide (SO2), benzo[a] pyrene (BaP), nickel (Ni), cadmium (Cd), and lead (Pb). Emissions for these pollutants were grouped into four emission source categories (Mobile, Area, High Point, and Other Point sources). The dispersion of the pollutants was predicted with the CALPUFF dispersion model using the year 2005 emission rate data and meteorological records. The resulting annual average concentrations were combined with population data to predict the contribution of each individual source to population exposure. The iFs for different pollutant-source category combinations varied between 51 per million (PM from Mobile sources) and 0.013 per million (sulfate PM from High Point sources). The intraurban iF variability for Mobile sources primary PM emission was from 4 per million to 100 per million with the emission-weighted iF of 44 per million. These results propose that exposure due to intraurban air pollution emissions could be decreased more effectively by specifically targeting sources with high exposure potency rather than all sources. PMID:24913007
Complex network approach to fractional time series
NASA Astrophysics Data System (ADS)
Manshour, Pouya
2015-10-01
In order to extract correlation information inherited in stochastic time series, the visibility graph algorithm has been recently proposed, by which a time series can be mapped onto a complex network. We demonstrate that the visibility algorithm is not an appropriate one to study the correlation aspects of a time series. We then employ the horizontal visibility algorithm, as a much simpler one, to map fractional processes onto complex networks. The degree distributions are shown to have parabolic exponential forms with Hurst dependent fitting parameter. Further, we take into account other topological properties such as maximum eigenvalue of the adjacency matrix and the degree assortativity, and show that such topological quantities can also be used to predict the Hurst exponent, with an exception for anti-persistent fractional Gaussian noises. To solve this problem, we take into account the Spearman correlation coefficient between nodes' degrees and their corresponding data values in the original time series.
Complex network approach to fractional time series
Manshour, Pouya
2015-10-15
In order to extract correlation information inherited in stochastic time series, the visibility graph algorithm has been recently proposed, by which a time series can be mapped onto a complex network. We demonstrate that the visibility algorithm is not an appropriate one to study the correlation aspects of a time series. We then employ the horizontal visibility algorithm, as a much simpler one, to map fractional processes onto complex networks. The degree distributions are shown to have parabolic exponential forms with Hurst dependent fitting parameter. Further, we take into account other topological properties such as maximum eigenvalue of the adjacency matrix and the degree assortativity, and show that such topological quantities can also be used to predict the Hurst exponent, with an exception for anti-persistent fractional Gaussian noises. To solve this problem, we take into account the Spearman correlation coefficient between nodes' degrees and their corresponding data values in the original time series.
For airborne toxic particles, the stochastic intake (SI) paradigm involves relativelylow numbers of particles that are presented for inhalation. Each person at risk may inhale adifferent number of particles, including zero particles. For such exposure scenarios, probabilistic d...
NASA Astrophysics Data System (ADS)
Lobscheid, Agnes B.; Nazaroff, William W.; Spears, Michael; Horvath, Arpad; McKone, Thomas E.
2012-12-01
Vehicular air pollutant emissions are characterized by a high degree of spatial variability that is correlated with the distribution of people. The consequences of the spatial association between emissions and exposed populations have not been fully captured in lifecycle and other impact assessments. The intake fraction (iF) quantifies aggregate air-pollutant exposures attributable to sources. Utilizing source-receptor (S-R) relationships derived from the US Environmental Protection Agency's AERMOD steady-state plume model, we quantify the intake fraction of conserved pollutants emitted from on-road mobile sources and report here the first characterization across approximately 65,000 census tracts of the conterminous United States. Considering exposures out to 50 km from the source, the population-weighted mean iF is 8.6 parts per million (ppm). The population-weighted median generally increases with geographic scale, from 3.6 ppm for census tracts to 4.2 ppm for counties, and 5.1 ppm for states, while the population-weighted interquartile range (IQR) progressively narrows as geographic scale increases: 0.85-8.8 ppm for census tracts, 1.5-8.5 ppm for counties, and 3.2-7.5 ppm for states. Across the four US Census regions, the population weighted median iF varies from 2.2 ppm (South) to 7.5 ppm (West), and the census-tract IQR spans an order of magnitude in each region (2.1-17 ppm in the West; 0.55-6.9 ppm in the Midwest; 0.45-5.5 ppm in the South; and 1.8-18 ppm in the Northeast). The population-weighted mean intake fraction for populous urban counties is about two orders of magnitude greater than for sparsely populated rural counties. On a population-weighted average basis and considering the 50 km analysis range, 75% of the intake occurs in the same county as emissions.
NASA Astrophysics Data System (ADS)
Petrov, Olga; Bi, Xiaotao; Lau, Anthony
2015-08-01
This study contributes to the literature by proposing a novel, state-of-the-art approach to estimate incremental air quality and health impacts of proposed or installed district energy systems (DES), such as the growing biomass-based DES, on the immediately surrounding community where population density varies significantly during day as well as the micrometeorological conditions. Spatial and temporal dynamics of pollutant concentrations at sensitive receptors obtained from modeled actual source emissions, inclusion of site-specific terrain, land use and microclimatic characteristics, population density and breathing rates are examined based on their impacts on the exposure potential expressed by the intake fraction (iF). Overall, results revealed that when those parameters are changing, the increase of iF calculated based on average ambient concentrations at each receptor for the UBC campus for the day and night hours for September 2012, ranges from 6.2% to 43.0%: introducing actual spatial receptor distribution led to 43% increase of iF, combined spatial and population dynamics led to 11.3% increase of iF, while introducing temporal dynamics and varying breathing rates resulted in 6.2% and 21.4% increase in iF respectively, compared to the base case box model where receptors and population were treated as static and uniformly distributed across the modeling domain. It is thus essential to take into consideration temporal and spatial variations of atmospheric conditions and dispersion, population density and varying aspiration rates in accurately assessing the health impacts of DES located at densely populated urban communities.
Zhou, Ping; Bai, Rongji
2014-01-01
Based on a new stability result of equilibrium point in nonlinear fractional-order systems for fractional-order lying in 1 < q < 2, one adaptive synchronization approach is established. The adaptive synchronization for the fractional-order Lorenz chaotic system with fractional-order 1 < q < 2 is considered. Numerical simulations show the validity and feasibility of the proposed scheme. PMID:25247207
A Novel Effective Approach for Solving Fractional Nonlinear PDEs
Aminikhah, Hossein; Malekzadeh, Nasrin; Rezazadeh, Hadi
2014-01-01
The present work introduces an effective modification of homotopy perturbation method for the solution of nonlinear time-fractional biological population model and a system of three nonlinear time-fractional partial differential equations. In this approach, the solution is considered a series expansion that converges to the nonlinear problem. The new approximate analytical procedure depends only on two iteratives. The analytical approximations to the solution are reliable and confirm the ability of the new homotopy perturbation method as an easy device for computing the solution of nonlinear equations.
Marinangeli, Christopher P F; Jones, Peter J H
2011-12-01
Effects of dietary fibers on human postprandial energetics remain undefined. The objective of the present study was to explore effects of whole yellow pea flour (WPF) and fractionated pea flour (FPF) on postprandial energy expenditure, substrate utilization, and hepatic triglyceride synthesis rate. Using a crossover-diet controlled design, 23 overweight men and women received muffins containing WPF, FPF, and white wheat flour (WF) for 28 days, followed by 28-day washout periods. Subjects received 50 g/day WPF and WF. Given that FPF is approximately 84% fiber, the amount of FPF administered to volunteers was equivalent to the amount of pea-derived fiber in the WPF treatment. Four weeks of FPF consumption reduced (P=.007) total postprandial energy expenditure (333.0±3.6 kcal/330 minutes) compared with WF (349.3±3.6 kcal/330 minutes). When values were normalized to the level of food energy consumed, FPF (4.6±0.3%) decreased (P=.018) the thermic effect of food (TEF) compared with WF (5.7±0.3%). Carbohydrate oxidation tended to be lower (P=.075) with FPF (44.7±2.1 g/330 minutes) versus WF (51.2±0.1.9 g/330 minutes). WPF had no effect on total energy expenditure, TEF, or carbohydrate oxidation. Only after 370 minutes was cumulative oxidation of [1-(13)C]palmitic acid higher (P=.045) in the WPF group (0.96±0.05%) compared with FPF (0.81±0.05%). Neither treatment had any effect on hepatic triglyceride synthesis rate. In conclusion, chronic ingestion of different fractions of yellow peas imposes distinctive effects on postprandial energy expenditure and substrate utilization. PMID:22145774
NASA Astrophysics Data System (ADS)
Tainio, Marko; Sofiev, Mikhail; Hujo, Mika; Tuomisto, Jouni T.; Loh, Miranda; Jantunen, Matti J.; Karppinen, Ari; Kangas, Leena; Karvosenoja, Niko; Kupiainen, Kaarle; Porvari, Petri; Kukkonen, Jaakko
The intake fraction (iF) has been defined as the integrated incremental intake of a pollutant released from a source category or region summed over all exposed individuals. In this study we evaluated the iFs in the population of Europe for emissions of anthropogenic primary fine particulate matter (PM 2.5) from sources in Europe, with a more detailed analysis of the iF from Finnish sources. Parameters for calculating the iFs include the emission strengths, the predicted atmospheric concentrations, European population data, and the average breathing rate per person. Emissions for the whole of Europe and Finland were based on the inventories of the European Monitoring and Evaluation Programme (EMEP) and the Finnish Regional Emission Scenario (FRES) model, respectively. The atmospheric dispersion of primary PM 2.5 was computed using the regional-scale dispersion model SILAM. The iFs from Finnish sources were also computed separately for six emission source categories. The iFs corresponding to the primary PM 2.5 emissions from the European countries for the whole population of Europe were generally highest for the densely populated Western European countries, second highest for the Eastern and Southern European countries, and lowest for the Northern European and Baltic countries. For the entire European population, the iF values varied from the lowest value of 0.31 per million for emissions from Cyprus, to the highest value of 4.42 per million for emissions from Belgium. These results depend on the regional distribution of the population and the prevailing long-term meteorological conditions. Regarding Finnish primary PM 2.5 emissions, the iF was highest for traffic emissions (0.68 per million) and lowest for major power plant emissions (0.50 per million). The results provide new information that can be used to find the most cost-efficient emission abatement strategies and policies.
NASA Astrophysics Data System (ADS)
Fagerlund, F.; Niemi, A.
2007-01-01
The subsurface spreading behaviour of gasoline, as well as several other common soil- and groundwater pollutants (e.g. diesel, creosote), is complicated by the fact that it is a mixture of hundreds of different constituents, behaving differently with respect to e.g. dissolution, volatilisation, adsorption and biodegradation. Especially for scenarios where the non-aqueous phase liquid (NAPL) phase is highly mobile, such as for sudden spills in connection with accidents, it is necessary to simultaneously analyse the migration of the NAPL and its individual components in order to assess risks and environmental impacts. Although a few fully coupled, multi-phase, multi-constituent models exist, such models are highly complex and may be time consuming to use. A new, somewhat simplified methodology for modelling the subsurface migration of gasoline while taking its multi-constituent nature into account is therefore introduced here. Constituents with similar properties are grouped together into eight fractions. The migration of each fraction in the aqueous and gaseous phases as well as adsorption is modelled separately using a single-constituent multi-phase flow model, while the movement of the free-phase gasoline is essentially the same for all fractions. The modelling is done stepwise to allow updating of the free-phase gasoline composition at certain time intervals. The output is the concentration of the eight different fractions in the aqueous, gaseous, free gasoline and solid phases with time. The approach is evaluated by comparing it to a fully coupled multi-phase, multi-constituent numerical simulator in the modelling of a typical accident-type spill scenario, based on a tanker accident in northern Sweden. Here the PCFF method produces results similar to those of the more sophisticated, fully coupled model. The benefit of the method is that it is easy to use and can be applied to any single-constituent multi-phase numerical simulator, which in turn may have
An Alternative Approach to Understanding the Observed Positron Fraction
NASA Astrophysics Data System (ADS)
Israel, Martin H.
2014-10-01
Space-based observations by PAMELA (Adriani et al., Nature 458, 607, 2009), Fermi-LAT (Ackerman et al., Phys. Rev. Lett. 105, 01103, 2012), and AMS (Aguilar et al., Phys. Rev. Lett. 110, 141102, 2013) have demonstrated that the positron fraction (e+/total-e) increases with increasing energy above about 10 GeV. According to the propagation model for Galactic cosmic rays in widespread use (Moskalenko & Strong, Astrophys. J. 493, 693, 1998), the production of secondary positrons from interaction of cosmic-ray protons and heavier nuclei with the interstellar medium gives a generally falling positron fraction between 10 and 100 GeV, with secondary positrons accounting for only ˜20 % of the observed positron fraction at 100 GeV; so some other physical phenomena have been proposed to explain the data. An alternative approach to interpreting the positron observations is to consider these data as presenting an opportunity for re-examining models of Galactic cosmic-ray propagation. Following release of the PAMELA data, three groups published propagation models (Shaviv, et al., Phys. Rev. Lett. 103, 111302, 2009, Cowsik and Burch, Phys. Rev. D. 82, 023009, 2010, Katz et al., Mon. Not. R. Aston. Soc. 405, 1458 2010) in which the observed positron fraction is explained entirely by secondary positrons produced in the interstellar medium. In May of this year, stimulated by the AMS extension of the positron data to higher energy with excellent statistics, two of those groups presented further development of their calculations (Cowsik et al. 2013, Blum et al. 2013), again concluding that the observed positrons can be understood as secondaries. None of the authors of these five papers was registered for the 33rd International Cosmic Ray Conference (ICRC). Although I am not an author of any of these papers, I have some close familiarity with one of these recent papers, so the conference organizers invited me to bring this alternative approach to the attention of the conference. The
A Fractional Variational Approach to the Fractional Basset-Type Equation
NASA Astrophysics Data System (ADS)
Baleanu, Dumitru; Garra, Roberto; Petras, Ivo
2013-08-01
In this paper we discuss an application of fractional variational calculus to the Basset-type fractional equations. It is well known that the unsteady motion of a sphere immersed in a Stokes fluid is described by an integro-differential equation involving derivative of real order. Here we study the inverse problem, i.e. we consider the problem from a Lagrangian point of view in the framework of fractional variational calculus. In this way we find an application of fractional variational methods to a classical physical model, finding a Basset-type fractional equation starting from a Lagrangian depending on derivatives of fractional order.
Frequency domain system identification methods - Matrix fraction description approach
NASA Technical Reports Server (NTRS)
Horta, Luca G.; Juang, Jer-Nan
1993-01-01
This paper presents the use of matrix fraction descriptions for least-squares curve fitting of the frequency spectra to compute two matrix polynomials. The matrix polynomials are intermediate step to obtain a linearized representation of the experimental transfer function. Two approaches are presented: first, the matrix polynomials are identified using an estimated transfer function; second, the matrix polynomials are identified directly from the cross/auto spectra of the input and output signals. A set of Markov parameters are computed from the polynomials and subsequently realization theory is used to recover a minimum order state space model. Unevenly spaced frequency response functions may be used. Results from a simple numerical example and an experiment are discussed to highlight some of the important aspect of the algorithm.
Hawkes, Corinna; Webster, Jacqui
2012-01-01
Aims There is strong evidence that diets high in salt are bad for health and that salt reduction strategies are cost effective. However, whilst it is clear that most people are eating too much salt, obtaining an accurate assessment of population salt intake is not straightforward, particularly in resource poor settings. The objective of this study is to identify what approaches governments are taking to monitoring salt intake, with the ultimate goal of identifying what actions are needed to address challenges to monitoring salt intake, especially in low and middle-income countries. Methods and Results A written survey was issued to governments to establish the details of their monitoring methods. Of the 30 countries that reported conducting formal government salt monitoring activities, 73% were high income countries. Less than half of the 30 countries, used the most accurate assessment of salt through 24 hour urine, and only two of these were developing countries. The remainder mainly relied on estimates through dietary surveys. Conclusions The study identified a strong need to establish more practical ways of assessing salt intake as well as technical support and advice to ensure that low and middle income countries can implement salt monitoring activities effectively. PMID:23082128
Convergent approaches to determine an ecosystem's transpiration fraction
NASA Astrophysics Data System (ADS)
Berkelhammer, M.; Noone, D. C.; Wong, T. E.; Burns, S. P.; Knowles, J. F.; Kaushik, A.; Blanken, P. D.; Williams, M. W.
2016-06-01
The transpiration (T) fraction of total terrestrial evapotranspiration (ET), T/ET, can vary across ecosystems between 20-95% with a global average of ˜60%. The wide range may either reflect true heterogeneity between ecosystems and/or uncertainties in the techniques used to derive this property. Here we compared independent approaches to estimate T/ET at two needleleaf forested sites with a factor of 3 difference in leaf area index (LAI). The first method utilized water vapor isotope profiles and the second derived transpiration through its functional relationship with gross primary production. We found strong agreement between T/ET values from these two independent approaches although we noted a discrepancy at low vapor pressure deficits (VPD). We hypothesize that this divergence arises because stomatal conductance is independent of humidity at low VPD. Overall, we document significant synoptic-scale T/ET variability but minimal growing season-scale variability. This result indicates a high sensitivity of T/ET to passing weather but convergence toward a stable mean state, which is set by LAI. While changes in T/ET could emerge from a myriad of processes, including aboveground (LAI) or belowground (rooting depth) changes, there was only minimal interannual variability and no secular trend in our analysis of T/ET from the 15 year eddy covariance time series at Niwot Ridge. If the lack of trend observed here is apparent elsewhere, it suggests that the processes controlling the T and E fluxes are coupled in a way to maintain a stable ratio.
A Study of Two-Term Unit Fraction Expansions via Geometric Approach
ERIC Educational Resources Information Center
Man, Yiu-Kwong
2009-01-01
In this article, we report a study of two-term unit fraction expansions using a geometric approach. It provides us insight on how to find all two-term unit fraction expansions and identify the property of the expansions with smallest maximal denominators, for a given unit fraction. These findings will be useful to lecturers or teachers involved in…
New Approach for Fractioning Metal Compounds Studies in Soils
NASA Astrophysics Data System (ADS)
Minkina, Tatiana; Motuzova, Galina; Mandzhieva, Saglara; Bauer, Tatiana; Burachevskaya, Marina; Sushkova, Svetlana; Nevidomskaya, Dina; Kalinitchenko, Valeriy
2016-04-01
A combined approach for fractioning metal compounds in soils on the basis of sequential (Tessier, 1979) and parallel extractions (1 N NH4Ac, pH 8; 1% EDTA in NH4Ac; and 1N HCl) is proposed. Metal compounds in sequential and parallel extracts are grouped according to the strength of their bonds with soil components. A given group includes metal compounds with similar strengths of bonds and, hence, with similar migration capacities. The groups of firmly and loosely bound metal compounds can be distinguished. This approach has been used to assess the group composition of Zn, Cu, and Pb compounds in an ordinary chernozem and its changes upon the soil contamination with metals. Contamination of an ordinary chernozem from Rostov oblast with heavy metals caused a disturbance of the natural ratios between the metal compounds. In the natural soil, firmly bound metals predominate (88-95%of the total content), which is mainly caused by the fixation of metals in lattices of silicate minerals (56-83%of the total content). The mobility of the metals in the natural soil is low (5-12%) and is mainly related to metal compounds loosely bound with the soil carbonates. Upon the soil contamination with metals (application rates of 100-300 mg/kg), the content of all the metal compounds increases, but the ratio between them shifts towards a higher portion of the potentially mobile metal compounds (up to 30-40% of the bulk contents of the metals). Organic substances and non-silicate Fe, Al, and Mn minerals become the main carriers of the firmly and loosely bound metals. The strengths of their bonds with Cu, Pb, and Zn differ. Lead in the studied chernozems is mainly fixed in a loosely bound form with organic matter, whereas copper and zinc are fixed both by the organic matter and by the non-silicate Fe, Al, and Mn compounds. Firm fixation of the applied Cu and Pb is mainly ensured by the soil organic matter and non-silicate minerals, whereas firm fixation of Zn is mainly due to non
Fractional System Identification: An Approach Using Continuous Order-Distributions
NASA Technical Reports Server (NTRS)
Hartley, Tom T.; Lorenzo, Carl F.
1999-01-01
This paper discusses the identification of fractional- and integer-order systems using the concept of continuous order-distribution. Based on the ability to define systems using continuous order-distributions, it is shown that frequency domain system identification can be performed using least squares techniques after discretizing the order-distribution.
Anomalous rotational relaxation: a fractional Fokker-Planck equation approach.
Aydiner, Ekrem
2005-04-01
In this study we have analytically obtained the relaxation function in terms of rotational correlation functions based on Brownian motion for complex disordered systems in a stochastic framework. We found out that the rotational relaxation function has a fractional form for complex disordered systems, which indicates that relaxation has nonexponential character and obeys the Kohlrausch-William-Watts law, following the Mittag-Leffler decay. PMID:15903722
Paradox of enrichment: A fractional differential approach with memory
NASA Astrophysics Data System (ADS)
Rana, Sourav; Bhattacharya, Sabyasachi; Pal, Joydeep; N'Guérékata, Gaston M.; Chattopadhyay, Joydev
2013-09-01
The paradox of enrichment (PoE) proposed by Rosenzweig [M. Rosenzweig, The paradox of enrichment, Science 171 (1971) 385-387] is still a fundamental problem in ecology. Most of the solutions have been proposed at an individual species level of organization and solutions at community level are lacking. Knowledge of how learning and memory modify behavioral responses to species is a key factor in making a crucial link between species and community levels. PoE resolution via these two organizational levels can be interpreted as a microscopic- and macroscopic-level solution. Fractional derivatives provide an excellent tool for describing this memory and the hereditary properties of various materials and processes. The derivatives can be physically interpreted via two time scales that are considered simultaneously: the ideal, equably flowing homogeneous local time, and the cosmic (inhomogeneous) non-local time. Several mechanisms and theories have been proposed to resolve the PoE problem, but a universally accepted theory is still lacking because most studies have focused on local effects and ignored non-local effects, which capture memory. Here we formulate the fractional counterpart of the Rosenzweig model and analyze the stability behavior of a system. We conclude that there is a threshold for the memory effect parameter beyond which the Rosenzweig model is stable and may be used as a potential agent to resolve PoE from a new perspective via fractional differential equations.
Misawa, Takuma; Date, Yasuhiro; Kikuchi, Jun
2015-03-01
Daily intake information is important for an understanding of the metabolic fluctuation of humans exposed to environmental stimuli. However, little investigation has been performed on the variations in dietary intake as an input and the relationship with human fecal, urinary, and salivary metabolic fluctuations as output information triggered by daily dietary intake. In the present study, we describe a data-driven approach for visualizing the daily intake information on a nutritional scale and for evaluating input-output responses under uncontrolled diets in a human study. For the input evaluation of nutritional intake, we collected information about daily dietary intake and converted this information to numeric data of nutritional elements. Furthermore, for the evaluation of output metabolic, mineral, and microbiota responses, we characterized the metabolic, mineral, and microbiota variations of noninvasive human samples of feces, urine, and saliva. The data-driven approach captured significant differences in the fluctuation of intestinal microbiota and some metabolites caused by a high-protein and a high-fat diet in daily life. This approach should contribute to the metabolic assessment of humans affected by environmental and nutritional factors under unlimited and uncontrolled diets. PMID:25626911
A new approach to the Pontryagin maximum principle for nonlinear fractional optimal control problems
NASA Astrophysics Data System (ADS)
Ali, Hegagi M.; Pereira, Fernando Lobo; Gama, Sílvio M. A.
2016-09-01
In this paper, we discuss a new general formulation of fractional optimal control problems whose performance index is in the fractional integral form and the dynamics are given by a set of fractional differential equations in the Caputo sense. We use a new approach to prove necessary conditions of optimality in the form of Pontryagin maximum principle for fractional nonlinear optimal control problems. Moreover, a new method based on a generalization of the Mittag-Leffler function is used to solving this class of fractional optimal control problems. A simple example is provided to illustrate the effectiveness of our main result.
A path integral approach to fractional quantum Hall effect
Kvale, M.N.
1989-01-01
In this paper the author reformulates and further develops the cooperative-ring-exchange (CRE) theory of the fractional quantum Hall effect. Initially, a classical two-dimensional electron gas is considered and a guiding-center approximation is made for strong magnetic fields. The resulting Lagrangian is quantized via path integration and the integral is evaluated using the semiclassical approximation. By considering the CRE processes and a time discretization procedure, the 2DEG is mapped to two different lattice models that bracket the behavior of the system. Analysis of the behavior of the system shows an underlying modular symmetry and allows one to made some new experimental predictions. By interpreting the CRE processes as a loop-space formulation of a lattice gauge field theory, a Landau-Ginzburg action is derived that contains most of the important physics associated with the FQHE and chose ground state can be identified with the Laughlin wave function. Finally, the Laughlin wave function is derived directly from the partition function in the FQHE regime.
An Improved Heaviside Approach to Partial Fraction Expansion and Its Applications
ERIC Educational Resources Information Center
Man, Yiu-Kwong
2009-01-01
In this note, we present an improved Heaviside approach to compute the partial fraction expansions of proper rational functions. This method uses synthetic divisions to determine the unknown partial fraction coefficients successively, without the need to use differentiation or to solve a system of linear equations. Examples of its applications in…
Fractional generalization of Fick's law: a microscopic approach
Calvo, Ivan; Sanchez, Raul; Carreras, Benjamin A; van Milligen, B. Ph.
2007-01-01
In the study of transport in inhomogeneous systems it is common to construct transport equations invoking the inhomogeneous Fick law. The validity of this approach requires that at least two ingredients be present in the system. First, finite characteristic length and time scales associated to the dominant transport process must exist. Secondly, the transport mechanism must satisfy a microscopic symmetry: global reversibility. Global reversibility is often satisfied in nature. However, many complex systems exhibit a lack of finite characteristic scales. In this Letter we show how to construct a generalization of the inhomogeneous Fick law that does not require the existence of characteristic scales while still satisfying global reversibility.
Fractional generalization of Fick's law: a microscopic approach.
Calvo, I; Sánchez, R; Carreras, B A; van Milligen, B Ph
2007-12-01
In the study of transport in inhomogeneous systems it is common to construct transport equations invoking the inhomogeneous Fick law. The validity of this approach requires that at least two ingredients be present in the system. First, finite characteristic length and time scales associated with the dominant transport process must exist. Second, the transport mechanism must satisfy a microscopic symmetry: global reversibility. Global reversibility is often satisfied in nature. However, many complex systems exhibit a lack of finite characteristic scales. In this Letter we show how to construct a generalization of the inhomogeneous Fick law that does not require the existence of characteristic scales while still satisfying global reversibility. PMID:18233351
MacLeod, Matthew; Bennett, Deborah H.; Perem, Merike; Maddalena, Randy L.; M cKone, Thomas E.; Mackay, Don
2003-03-01
The extent of human exposure to persistent anthropogenic environmental contaminants is a complex function of the amount of chemical emitted, its physico-chemical properties and reactivity, the nature of the environment, and the characteristics of the pathways for human exposure, such as inhalation, intake of food and water and dermal contact. For some chemicals, the location of emissions relative to areas of high population density or intense food production may also be an important factor. The relative importance of these variables is explored using the regionally segmented BETR North America contaminant fate model and data for food production patterns and population density for North America. The model is applied to four contaminants emitted to air: benzene, carbon tetrachloride, benzo[a]pyrene and 2,3,7,8-tetrachlorodibenzo dioxin. The total continental intake fraction (iF), relating exposure quantity to emission quantity, is employed as a metric for assessing population exposure to environmental contaminants. The results show that the use of continentally averaged parameters for population density and food production provides an accurate estimate of the median of iF calculated for emissions in individual regions, however iF can range from this median by up to 3 orders of magnitude, especially for chemicals transferred to humans through the food pathway. The location of population relative to food production and emissions of chemicals are important variables that should be considered in assessing the public health implications of chemical emissions.
NASA Astrophysics Data System (ADS)
Ezz-Eldien, S. S.
2016-07-01
This manuscript presents a new numerical approach to approximate the solution of a class of fractional variational problems. The presented approach is consisting of using the shifted Legendre orthonormal polynomials as basis functions of the operational matrix of fractional derivatives (described in the Caputo sense) and that of fractional integrals (described in the sense of Riemann-Liouville) with the help of the Legendre-Gauss quadrature formula together with the Lagrange multipliers method for converting such fractional variational problems into easier problems that consist of solving an algebraic system in the unknown coefficients. The convergence of the proposed method is analyzed. Finally, in order to demonstrate the accuracy of the present method, some test problems are introduced with their approximate solutions and comparisons with other numerical approaches.
Adams, S.M.; Vaughan, D.S.; Hildebrand, S.G.; Kumar, K.D.
1981-04-01
Assessment approaches and strategies useful in addressing important issues in section 316(b) of the 1972 Federal Water Pollution Control Act are illustrated in this report through the analysis and evaluation of the Prairie Island Nuclear Station 316(b) data base. The main issues in 316(b) demonstrations, cooling water intake operation and location, involve determining the impacts of entrainment and impingement. Entrainment impacts were addressed by applying the equivalent adult approach and correcting for inherent biases and by determining the through-plant survival of zooplankton. An assessment of impingement impacts was made by comparing for each of various species the number of fish impinged to estimates of population size. Densities of plankton and fish were compared between the intake area and an alternate area to determine if the location of the present intake minimizes impacts. No definitive conclusion relative to the best location of the intake could be made because of high year to year variability in the data and the differential dominance of trophic groups between areas.
Llorach, Rafael; Medina, Sonia; García-Viguera, Cristina; Zafrilla, Pilar; Abellán, José; Jauregui, Olga; Tomás-Barberán, Francisco A; Gil-Izquierdo, Angel; Andrés-Lacueva, Cristina
2014-06-01
Metabolomics has emerged in the field of food and nutrition sciences as a powerful tool for doing profiling approaches. In this context, HPLC-q-TOF-based metabolomics approach was applied to unveil changes in the urinary metabolome in human subjects (n = 51, 23 men and 28 women) after regular aronia-citrus juice (AC-juice) intake (250 mL/day) during 16 weeks compared to individuals given a placebo beverage. Samples were analyzed by HPLC-q-TOF followed by multivariate data analysis (orthogonal signal filtering-partial least square discriminant analysis) that discriminated relevant mass features related to AC-juice intake. The results showed that biomarkers of AC-juice intake including metabolites coming from metabolism of food components as proline betaine, ferulic acid, and two unknown mercapturate derivatives were identified. Discovery of new biomarkers of food intake will help in the building up of the food metabolome and facilitate future insights into the mechanisms of action of dietary components in population health. PMID:24616048
Gimbert, Frédéric; Geffard, Alain; Guédron, Stéphane; Dominik, Janusz; Ferrari, Benoit J D
2016-02-01
Along with the growing body of evidence that total internal concentration is not a good indicator of toxicity, the Critical Body Residue (CBR) approach recently evolved into the Tissue Residue Approach (TRA) which considers the biologically active portion of metal that is available to contribute to the toxicity at sites of toxic action. For that purpose, we examined total mercury (Hg) bioaccumulation and subcellular fractionation kinetics in fourth stage larvae of the midge Chironomus riparius during a four-day laboratory exposure to Hg-spiked sediments and water. The debris (including exoskeleton, gut contents and cellular debris), granule and organelle fractions accounted only for about 10% of the Hg taken up, whereas Hg concentrations in the entire cytosolic fraction rapidly increased to approach steady-state. Within this fraction, Hg compartmentalization to metallothionein-like proteins (MTLP) and heat-sensitive proteins (HSP), consisting mostly of enzymes, was assessed in a comparative manner by two methodologies based on heat-treatment and centrifugation (HT&C method) or size exclusion chromatography separation (SECS method). The low Hg recoveries obtained with the HT&C method prevented accurate analysis of the cytosolic Hg fractionation by this approach. According to the SECS methodology, the Hg-bound MTLP fraction increased linearly over the exposure duration and sequestered a third of the Hg flux entering the cytosol. In contrast, the HSP fraction progressively saturated leading to Hg excretion and physiological impairments. This work highlights several methodological and biological aspects to improve our understanding of Hg toxicological bioavailability in aquatic invertebrates. PMID:26688328
A matrix approach for partial differential equations with Riesz space fractional derivatives
NASA Astrophysics Data System (ADS)
Popolizio, M.
2013-09-01
Fractional partial differential equations are emerging in many scientific fields and their numerical solution is becoming a fundamental topic. In this paper we consider the Riesz fractional derivative operator and its discretization by fractional centered differences. The resulting matrix is studied, with an interesting result on a connection between the decay behavior of its entries and the short memory principle from fractional calculus. The Shift-and-Invert method is then applied to approximate the solution of the partial differential equation as the action of the matrix exponential on a suitable vector which mimics the given initial conditions. The numerical results confirm the good approximation quality and encourage the use of the proposed approach.
A unified approach for the numerical solution of time fractional Burgers' type equations
NASA Astrophysics Data System (ADS)
Esen, A.; Bulut, F.; Oruç, Ö.
2016-04-01
In this paper, a relatively new approach is devised for obtaining approximate solution of time fractional partial differential equations. Time fractional diffusion equation and time fractional Burgers-Fisher equation are solved with Haar wavelet method where fractional derivatives are Caputo derivative. Time discretization of the problems made by L1 discretization formula and space derivatives discretized by Haar series. L2 and L_{∞} error norms are used for measuring accuracy of the proposed method. Numerical results obtained with proposed method compared with exact solutions as well as with available results from the literature. The numerical results verify the feasibility of Haar wavelet combined with L1 discretization formula for the considered problems.
Cikes, Maja; Solomon, Scott D
2016-06-01
Left ventricular ejection fraction (LVEF) has been the central parameter used for diagnosis and management in patients with heart failure. A good predictor of adverse outcomes in heart failure when below ∼45%, LVEF is less useful as a marker of risk as it approaches normal. As a measure of cardiac function, ejection fraction has several important limitations. Calculated as the stroke volume divided by end-diastolic volume, the estimation of ejection fraction is generally based on geometric assumptions that allow for assessment of volumes based on linear or two-dimensional measurements. Left ventricular ejection fraction is both preload- and afterload-dependent, can change substantially based on loading conditions, is only moderately reproducible, and represents only a single measure of risk in patients with heart failure. Moreover, the relationship between ejection fraction and risk in patients with heart failure is modified by factors such as hypertension, diabetes, and renal function. A more complete evaluation and understanding of left ventricular function in patients with heart failure requires a more comprehensive assessment: we conceptualize an integrative approach that incorporates measures of left and right ventricular function, left ventricular geometry, left atrial size, and valvular function, as well as non-imaging factors (such as clinical parameters and biomarkers), providing a comprehensive and accurate prediction of risk in heart failure. PMID:26417058
CONCEPTUAL BASIS FOR MULTI-ROUTE INTAKE DOSE MODELING USING AN ENERGY EXPENDITURE APPROACH
This paper provides the conceptual basis for a modeling logic that is currently being developed in the National Exposure Research Laboratory (NERL) of the U.S. Environmental Protection Agency ( EPA) for use in intake dose assessments involving substances that can enter the body...
Lu, Jun; Song, Hui-Peng; Li, Ping; Zhou, Ping; Dong, Xin; Chen, Jun
2015-05-10
Thrombin plays a significant role in thromboembolic disease. In this work, a peak fractionation approach combined with an activity assay method was used to screen direct thrombin inhibitors from Radix Salviae Miltiorrhizae (RSM), a famous herbal remedy for the treatment of cardiovascular diseases in China. A total of 91 fractions were collected from the RSM extract, and 19 fractions out of them showed thrombin inhibitory effects with dose-effect relationship. Among them, three compounds were unambiguously identified as 15, 16-dihydrotanshinone I, cryptotanshinone and tanshinone IIA with IC50 values of 29.39, 81.11 and 66.60μM, respectively. The three compounds were reported with direct thrombin inhibition activities for the first time and their ligand-thrombin interactions were explored by a molecular docking research. These results may contribute to explain the medical benefit of RSM for the prevention and treatment of cardiovascular diseases. PMID:25819728
NASA Astrophysics Data System (ADS)
Kim, M.; Ghate, A.; Phillips, M. H.
2009-07-01
The current state of the art in cancer treatment by radiation optimizes beam intensity spatially such that tumors receive high dose radiation whereas damage to nearby healthy tissues is minimized. It is common practice to deliver the radiation over several weeks, where the daily dose is a small constant fraction of the total planned. Such a 'fractionation schedule' is based on traditional models of radiobiological response where normal tissue cells possess the ability to repair sublethal damage done by radiation. This capability is significantly less prominent in tumors. Recent advances in quantitative functional imaging and biological markers are providing new opportunities to measure patient response to radiation over the treatment course. This opens the door for designing fractionation schedules that take into account the patient's cumulative response to radiation up to a particular treatment day in determining the fraction on that day. We propose a novel approach that, for the first time, mathematically explores the benefits of such fractionation schemes. This is achieved by building a stylistic Markov decision process (MDP) model, which incorporates some key features of the problem through intuitive choices of state and action spaces, as well as transition probability and reward functions. The structure of optimal policies for this MDP model is explored through several simple numerical examples.
Chen, Fei; Anderson, William B; Huck, Peter M
2013-01-01
To assist in assessing a potential contaminated sediment threat near a drinking water intake in a large lake, a technique known as the fingerprint analysis of leachate contaminants (FALCON), was investigated and enhanced to help draw more statistically significant definitive conclusions. This represents the first application of this approach, originally developed by the USEPA to characterize and track leachate penetration in groundwater and contaminant migration from waste and landfill sites, in a large lake from the point-of-view of source water protection. FALCON provided valuable information regarding contaminated sediment characterization, source attribution, and transport within a surface water context without the need for knowledge of local hydrodynamic conditions, potentially reducing reliance on complicated hydrodynamic analysis. A t-test to evaluate the significance of correlations was shown to further enhance the FALCON procedure. In this study, the sensitivity of FALCON was found to be improved by using concentration data from both conserved organics and heavy metals in combination. Furthermore, data analysis indicated that it may be possible to indirectly assess the success of remediation efforts (and the corresponding need to plan for a treatment upgrade in the event of escalating contaminant concentrations) by examining the temporal change in correlation between the source and intake sediment fingerprints over time. This method has potential for widespread application in situations where conserved contaminants such as heavy metals and higher molecular weight polycyclic aromatic hydrocarbons (PAHs), are being or have previously been deposited in sediment somewhere in, or within range of, an intake protection zone. PMID:23123114
On a fractional representation approach to closed-loop experiment design
NASA Technical Reports Server (NTRS)
Hansen, Fred R.; Franklin, Gene F.
1988-01-01
A plant model, based on a fractional representation of the loop, which is uniquely suited to the closed-loop experiment design problem, is proposed. The advantage of this model is that it substitutes an open-loop problem (for which there has been extensive work) for the original-closed loop problem. The results of Monte Carlo simulations which support the utility of this approach are included.
Application of fuzzy goal programming approach to multi-objective linear fractional inventory model
NASA Astrophysics Data System (ADS)
Dutta, D.; Kumar, Pavan
2015-09-01
In this paper, we propose a model and solution approach for a multi-item inventory problem without shortages. The proposed model is formulated as a fractional multi-objective optimisation problem along with three constraints: budget constraint, space constraint and budgetary constraint on ordering cost of each item. The proposed inventory model becomes a multiple criteria decision-making (MCDM) problem in fuzzy environment. This model is solved by multi-objective fuzzy goal programming (MOFGP) approach. A numerical example is given to illustrate the proposed model.
Drouillet-Pinard, Peggy; Boisset, Michel; Periquet, Alain; Lecerf, Jean-Michel; Casse, Francine; Catteau, Michel; Barnat, Saida
2011-01-01
The increase of fruit and vegetable (F&V) intake contributes to the prevention of chronic diseases, but could also significantly increase pesticide exposure and may thus be of health concern. Following a previous pesticide exposure assessment study, the present study was carried out to determine actual levels of pesticides within 400 g of F&V intake and to evaluate consumer risk. Forty-three Active Substances (AS) exceeding 10 % of the Acceptable Daily Intake (ADI) in balanced menus established for our previous theoretical study were considered. Fifty-six pooled food samples were analyzed: 28 fruit samples and 28 vegetable samples. Pesticide values were compared to Maximum Residue Levels (MRL) and to the "toxicological credit" derived from ADI. It was observed that 23 out of the 43 retained AS were never detected, 5 were detected both in F&V samples, 12 only in fruits and 3 only in vegetables. The most frequently detected AS were carbendazim, iprodione and dithiocarbamates. When detected, AS were more frequently found in fruit samples (74 %) than in vegetable samples (26 %). A maximum of 3 AS were detected at once in a given sample. Overall, we observed 8 and 14 overruns of the MRL in 1204 measures in pooled vegetable and fruit samples, respectively (0.7 % and 1.2 % of cases, respectively). Chronic exposure for adults was the highest for dithiocarbamates but did not exceed 23.7 % of the ADI in F&V. It was concluded that raising both F&V consumption up to 400 g/day (~5 F&V/day) according to recommendations of the national health and nutrition plan, does not induce pesticide overexposure and should not represent a risk for the consumer. PMID:21191868
Comparison of Flamelet Models with the Transported Mass Fraction Approach for Supersonic Combustion
NASA Astrophysics Data System (ADS)
Li, Wenhai; Alabi, Ken; Ladeinde, Foluso
2015-11-01
In this study, two fully compressible RANS, LES, and combined RANS/LES flow solvers - AEROFLO and VULCAN, both of which were originally developed by the United States Department of Defense but have since been significantly enhanced and commercialized by our organization, are used to investigate the accuracy of flamelet-based approach when employed to model supersonic combustion. The flamelet results from both codes are assessed relative to solutions obtained by solving the transport equations for the mass fractions - which is also supported by one of the codes, and making familiar assumptions about the closure of the reaction rate. The studies are carried out in the flamelet regime, and the numerical procedures are based on high-order schemes, which are also used to solve the level-set and mixture fraction transport equations used to study, respectively, premixed and non-premixed combustion. The effects of supersonic Mach numbers on the results are discussed.
Chaudhary, Naveed Ishtiaq; Raja, Muhammad Asif Zahoor; Khan, Junaid Ali; Aslam, Muhammad Saeed
2013-01-01
A novel algorithm is developed based on fractional signal processing approach for parameter estimation of input nonlinear control autoregressive (INCAR) models. The design scheme consists of parameterization of INCAR systems to obtain linear-in-parameter models and to use fractional least mean square algorithm (FLMS) for adaptation of unknown parameter vectors. The performance analyses of the proposed scheme are carried out with third-order Volterra least mean square (VLMS) and kernel least mean square (KLMS) algorithms based on convergence to the true values of INCAR systems. It is found that the proposed FLMS algorithm provides most accurate and convergent results than those of VLMS and KLMS under different scenarios and by taking the low-to-high signal-to-noise ratio. PMID:23853538
Bruins, Maaike J.; Mugambi, Gladys; Verkaik-Kloosterman, Janneke; Hoekstra, Jeljer; Kraemer, Klaus; Osendarp, Saskia; Melse-Boonstra, Alida; Gallagher, Alison M.; Verhagen, Hans
2015-01-01
Fortification of foods consumed by the general population or specific food products or supplements designed to be consumed by vulnerable target groups is amongst the strategies in developing countries to address micronutrient deficiencies. Any strategy aimed at dietary change needs careful consideration, ensuring the needs of at-risk subgroups are met whilst ensuring safety within the general population. This paper reviews the key principles of two main assessment approaches that may assist developing countries in deciding on effective and safe micronutrient levels in foods or special products designed to address micronutrient deficiencies, that is, the cut-point method and the stepwise approach to risk–benefit assessment. In the first approach, the goal is to shift population intake distributions such that intake prevalences below the Estimated Average Requirement (EAR) and above the Tolerable Upper Intake Level (UL) are both minimized. However, for some micronutrients like vitamin A and zinc, a narrow margin between the EAR and UL exists. Increasing their intakes through mass fortification may pose a dilemma; not permitting the UL to be exceeded provides assurance about the safety within the population but can potentially leave a proportion of the target population with unmet needs, or vice versa. Risk–benefit approaches assist in decision making at different micronutrient intake scenarios by balancing the magnitude of potential health benefits of reducing inadequate intakes against health risks of excessive intakes. Risk–benefit approaches consider different aspects of health risk including severity and number of people affected. This approach reduces the uncertainty for policy makers as compared to classic cut-point methods. PMID:25630617
Bauhoff, Sebastian
2014-01-01
School nutrition policies aim to eliminate ubiquitous unhealthy foods and beverages from schools to improve adolescent dietary behavior and reduce childhood obesity. This paper evaluates the impact of an early nutrition policy, Los Angeles Unified School District's food-and-beverage standards of 2004, using two large datasets on food intake and physical measures. I implement cohort and cross-section estimators using "synthetic" control groups, combinations of unaffected districts that are reweighted to closely resemble the treatment unit in the pre-intervention period. The results indicate that the policy was mostly ineffective at reducing the prevalence of overweight or obesity 8-15 months after the intervention but significantly decreased consumption of two key targets, soda and fried foods. The policy's impact on physical outcomes appears to be mitigated by substitution toward foods that are still (or newly) available in the schools. PMID:23891422
NASA Astrophysics Data System (ADS)
Shech, Elay
2015-09-01
This paper looks at the nature of idealizations and representational structures appealed to in the context of the fractional quantum Hall effect, specifically, with respect to the emergence of anyons and fractional statistics. Drawing on an analogy with the Aharonov-Bohm effect, it is suggested that the standard approach to the effects—(what we may call) the topological approach to fractional statistics—relies essentially on problematic idealizations that need to be revised in order for the theory to be explanatory. An alternative geometric approach is outlined and endorsed. Roles for idealizations in science, as well as consequences for the debate revolving around so-called essential idealizations, are discussed.
SLFP: A stochastic linear fractional programming approach for sustainable waste management
Zhu, H.; Huang, G.H.
2011-12-15
Highlights: > A new fractional programming (SLFP) method is developed for waste management. > SLFP can solve ratio optimization problems associated with random inputs. > A case study of waste flow allocation demonstrates its applicability. > SLFP helps compare objectives of two aspects and reflect system efficiency. > This study supports in-depth analysis of tradeoffs among multiple system criteria. - Abstract: A stochastic linear fractional programming (SLFP) approach is developed for supporting sustainable municipal solid waste management under uncertainty. The SLFP method can solve ratio optimization problems associated with random information, where chance-constrained programming is integrated into a linear fractional programming framework. It has advantages in: (1) comparing objectives of two aspects, (2) reflecting system efficiency, (3) dealing with uncertainty expressed as probability distributions, and (4) providing optimal-ratio solutions under different system-reliability conditions. The method is applied to a case study of waste flow allocation within a municipal solid waste (MSW) management system. The obtained solutions are useful for identifying sustainable MSW management schemes with maximized system efficiency under various constraint-violation risks. The results indicate that SLFP can support in-depth analysis of the interrelationships among system efficiency, system cost and system-failure risk.
ERIC Educational Resources Information Center
Man, Yiu-Kwong
2012-01-01
Partial fraction decomposition is a useful technique often taught at senior secondary or undergraduate levels to handle integrations, inverse Laplace transforms or linear ordinary differential equations, etc. In recent years, an improved Heaviside's approach to partial fraction decomposition was introduced and developed by the author. An important…
NASA Astrophysics Data System (ADS)
Lachhwani, Kailash; Poonia, Mahaveer Prasad
2012-08-01
In this paper, we show a procedure for solving multilevel fractional programming problems in a large hierarchical decentralized organization using fuzzy goal programming approach. In the proposed method, the tolerance membership functions for the fuzzily described numerator and denominator part of the objective functions of all levels as well as the control vectors of the higher level decision makers are respectively defined by determining individual optimal solutions of each of the level decision makers. A possible relaxation of the higher level decision is considered for avoiding decision deadlock due to the conflicting nature of objective functions. Then, fuzzy goal programming approach is used for achieving the highest degree of each of the membership goal by minimizing negative deviational variables. We also provide sensitivity analysis with variation of tolerance values on decision vectors to show how the solution is sensitive to the change of tolerance values with the help of a numerical example.
NASA Astrophysics Data System (ADS)
Zeng, Xiancheng; Hu, Hao; Hu, Xiangqian; Cohen, Aron J.; Yang, Weitao
2008-03-01
Electron transfer (ET) reactions are one of the most important processes in chemistry and biology. Because of the quantum nature of the processes and the complicated roles of the solvent, theoretical study of ET processes is challenging. To simulate ET processes at the electronic level, we have developed an efficient density functional theory (DFT) quantum mechanical (QM)/molecular mechanical (MM) approach that uses the fractional number of electrons as the order parameter to calculate the redox free energy of ET reactions in solution. We applied this method to study the ET reactions of the aqueous metal complexes Fe(H2O)62+/3+ and Ru(H2O)62+/3+. The calculated oxidation potentials, 5.82 eV for Fe(II/III) and 5.14 eV for Ru(II/III), agree well with the experimental data, 5.50 and 4.96 eV, for iron and ruthenium, respectively. Furthermore, we have constructed the diabatic free energy surfaces from histogram analysis based on the molecular dynamics trajectories. The resulting reorganization energy and the diabatic activation energy also show good agreement with experimental data. Our calculations show that using the fractional number of electrons (FNE) as the order parameter in the thermodynamic integration process leads to efficient sampling and validate the ab initio QM/MM approach in the calculation of redox free energies.
A solvent-free approach to extract the lipid fraction from sewer grease for biodiesel production.
Tu, Qingshi; Wang, Jingjing; Lu, Mingming; Brougham, Andrew; Lu, Ting
2016-08-01
Fats, oils and greases (FOG) are the number one cause of sewer pipe blockage and have been mostly disposed of as a waste until recently. This study investigated a low cost and environmentally friendly approach to extract the lipid fraction (fatty acids and glycerides for biodiesel production) from sewer grease (SG), i.e., FOGs obtained from wastewater treatment plants (WWTPs). The lipid fraction of the sewer grease was primarily in the form of free fatty acid (FFA), at 20.7wt%. An innovative solvent-free extraction approach was developed using waste cooking oil (WCO) to overcome the challenges of emulsion, impurities and high moisture content of the sewer grease. A 95% extraction yield of sewer grease was achieved under the optimum operating condition of 3.2:1 WCO-SG ratio (wt/wt), 70°C and 240min. In addition, the reusability of the WCO was also investigated. WCO can be used two to three times for sewer grease extraction with more than 90% extraction efficiency. PMID:27256783
Mendler, Edward Charles
2005-02-01
The volumetric efficiency and power of internal combustion engines is improved with an intake port having an intake nozzle, a venturi, and a surge chamber. The venturi is located almost halfway upstream the intake port between the intake valves and the intake plenum enabling the venturi throat diameter to be exceptionally small for providing an exceptionally high ram velocity and an exceptionally long and in turn high efficiency diffuser flowing into the surge chamber. The intake port includes an exceptionally large surge chamber volume for blow down of the intake air into the working cylinder of the engine.
Huijbregts, Mark A J; Geelen, Loes M J; Hertwich, Edgar G; McKone, Thomas E; van de Meent, Dik
2005-02-01
In life-cycle assessment (LCA) and comparative risk assessment, potential human exposure to toxic pollutants can be expressed as the population intake fraction (iF), which represents the fraction of the quantity emitted that enters the human population. To assess the influence of model differences in the calculation of the population iF ingestion and inhalation iFs of 365 substances emitted to air, freshwater, and soil were calculated with two commonly applied multimedia fate and exposure models, CalTOX and the uniform system for evaluation of substances adapted for life-cycle assessment (USES-LCA). The model comparison showed that differences in the iFs due to model choices were the lowest after emission to air and the highest after emission to soil. Inhalation iFs were more sensitive to model differences compared to ingestion iFs. The choice for a continental seawater compartment, vertical stratification of the soil compartment, rain and no-rain scenarios, and drinking water purification mainly clarify the relevant model differences found in population iFs. Furthermore, pH correction of chemical properties and aerosol-associated deposition on plants appeared to be important for dissociative organics and metals emitted to air, respectively. Finally, it was found that quantitative structure-activity relationship estimates for superhydrophobics may introduce considerable uncertainty in the calculation of population intake fractions. PMID:15720012
NASA Astrophysics Data System (ADS)
Lachhwani, Kailash; Nehra, Suresh
2015-09-01
In this paper, we present modified fuzzy goal programming (FGP) approach and generalized MATLAB program for solving multi-level linear fractional programming problems (ML-LFPPs) based on with some major modifications in earlier FGP algorithms. In proposed modified FGP approach, solution preferences by the decision makers at each level are not considered and fuzzy goal for the decision vectors is defined using individual best solutions. The proposed modified algorithm as well as MATLAB program simplifies the earlier algorithm on ML-LFPP by eliminating solution preferences by the decision makers at each level, thereby avoiding difficulties associate with multi-level programming problems and decision deadlock situation. The proposed modified technique is simple, efficient and requires less computational efforts in comparison of earlier FGP techniques. Also, the proposed coding of generalized MATLAB program based on this modified approach for solving ML-LFPPs is the unique programming tool toward dealing with such complex mathematical problems with MATLAB. This software based program is useful and user can directly obtain compromise optimal solution of ML-LFPPs with it. The aim of this paper is to present modified FGP technique and generalized MATLAB program to obtain compromise optimal solution of ML-LFP problems in simple and efficient manner. A comparative analysis is also carried out with numerical example in order to show efficiency of proposed modified approach and to demonstrate functionality of MATLAB program.
TOPSIS approach to linear fractional bi-level MODM problem based on fuzzy goal programming
NASA Astrophysics Data System (ADS)
Dey, Partha Pratim; Pramanik, Surapati; Giri, Bibhas C.
2014-07-01
The objective of this paper is to present a technique for order preference by similarity to ideal solution (TOPSIS) algorithm to linear fractional bi-level multi-objective decision-making problem. TOPSIS is used to yield most appropriate alternative from a finite set of alternatives based upon simultaneous shortest distance from positive ideal solution (PIS) and furthest distance from negative ideal solution (NIS). In the proposed approach, first, the PIS and NIS for both levels are determined and the membership functions of distance functions from PIS and NIS of both levels are formulated. Linearization technique is used in order to transform the non-linear membership functions into equivalent linear membership functions and then normalize them. A possible relaxation on decision for both levels is considered for avoiding decision deadlock. Then fuzzy goal programming models are developed to achieve compromise solution of the problem by minimizing the negative deviational variables. Distance function is used to identify the optimal compromise solution. The paper presents a hybrid model of TOPSIS and fuzzy goal programming. An illustrative numerical example is solved to clarify the proposed approach. Finally, to demonstrate the efficiency of the proposed approach, the obtained solution is compared with the solution derived from existing methods in the literature.
A theory-based approach to thermal field-flow fractionation of polyacrylates.
Runyon, J Ray; Williams, S Kim Ratanathanawongs
2011-09-28
A theory-based approach is presented for the development of thermal field-flow fractionation (ThFFF) of polyacrylates. The use of ThFFF for polymer analysis has been limited by an incomplete understanding of the thermal diffusion which plays an important role in retention and separation. Hence, a tedious trial-and-error approach to method development has been the normal practice when analyzing new materials. In this work, thermal diffusion theories based on temperature dependent osmotic pressure gradient and polymer-solvent interaction parameters were used to estimate thermal diffusion coefficients (D(T)) and retention times (t(r)) for different polymer-solvent pairs. These calculations identified methyl ethyl ketone as a solvent that would cause significant retention of poly(n-butyl acrylate) (PBA) and poly(methyl acrylate) (PMA). Experiments confirmed retention of these two polymers that have not been previously analyzed by ThFFF. Theoretical and experimental D(T)s and t(r)s for PBA, PMA, and polystyrene in different solvents agreed to within 20% and demonstrate the feasibility of this theory-based approach. PMID:21872869
Gatzoulis, Konstantinos A; Tsiachris, Dimitris; Arsenos, Petros; Tousoulis, Dimitris
2016-01-26
Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators (ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death. PMID:26839662
Podlubny, Igor; Skovranek, Tomas; Vinagre Jara, Blas M; Petras, Ivo; Verbitsky, Viktor; Chen, YangQuan
2013-05-13
In this paper, we further develop Podlubny's matrix approach to discretization of integrals and derivatives of non-integer order. Numerical integration and differentiation on non-equidistant grids is introduced and illustrated by several examples of numerical solution of differential equations with fractional derivatives of constant orders and with distributed-order derivatives. In this paper, for the first time, we present a variable-step-length approach that we call 'the method of large steps', because it is applied in combination with the matrix approach for each 'large step'. This new method is also illustrated by an easy-to-follow example. The presented approach allows fractional-order and distributed-order differentiation and integration of non-uniformly sampled signals, and opens the way to development of variable- and adaptive-step-length techniques for fractional- and distributed-order differential equations. PMID:23547230
Leturque, Armelle; Brot-Laroche, Edith; Le Gall, Maude
2012-01-01
Carbohydrates represent more than 50% of the energy sources present in most human diets. Sugar intake is regulated by metabolic, neuronal, and hedonic factors, and gene polymorphisms are involved in determining sugar preference. Nutrigenomic adaptations to carbohydrate availability have been evidenced in metabolic diseases, in the persistence of lactose digestion, and in amylase gene copy number. Furthermore, dietary oligosaccharides, fermentable by gut flora, can modulate the microbiotal diversity to the benefit of the host. Genetic diseases linked to mutations in the disaccharidase genes (sucrase-isomaltase, lactase) and in sugar transporter genes (sodium/glucose cotransporter 1, glucose transporters 1 and 2) severely impact carbohydrate intake. These diseases are revealed upon exposure to food containing the offending sugar, and withdrawal of this sugar from the diet prevents disease symptoms, failure to thrive, and premature death. Tailoring the sugar composition of diets to optimize wellness and to prevent the chronic occurrence of metabolic diseases is a future goal that may yet be realized through continued development of nutrigenetics and nutrigenomics approaches. PMID:22656375
Burbea, Z H; Luz, B; Lazar, B; Winaver, J; Better, O S
1983-01-01
Two alternative mechanisms have been proposed for tubular reabsorption of bicarbonate: (a) H+ secretion and CO2 reabsorption and (b) direct reabsorption of HCO-3. In an attempt to differentiate between the two mechanisms, the present study utilized the natural abundance of stable carbon isotopes (13C, 12C) in the urinary total CO2. This novel methodology used mass spectrometric analysis of 13C/12C ratios in urinary total CO2 under normal conditions and during acetazolamide treatment. Blood and respiratory CO2 were analyzed to yield reference values. The results demonstrate that alkaline urine is preferentially enriched with 13C relative to the blood. It is suggested that this fractionation results from reaction out of isotopic equilibrium in which HCO-3 converts to CO2 during the reabsorption process in the distal nephron. The presence of carbonic anhydrase in the proximal nephron results in rapid isotopic exchange between CO2 and HCO-3 and keeps them in isotopic equilibrium. The ratio of urinary 13C/12C increases strikingly after acetazolamide administration and consequent inhibition of carbonic anhydrase in the proximal tubule. Although it is possible that in the latter case high HCO-3 generates the CO2 (ampholyte effect), the isotope fractionation indicates that CO2 rather than HCO-3 is reabsorbed. In contrast, at low urinary pH and total CO2 values, the carbon isotope composition approaches that of blood CO2. This indicates rapid CO2 exchange between urine and blood, through luminal membrane highly permeable to CO2. These results could be anticipated by a mathematical model constructed to plot 13C concentration of urinary total CO2. It is concluded that the mechanism of HCO-3 reclamation in man (and, by inference, in other mammals as well) works by conversion of HCO-3 to CO2 and reabsorption of CO2. PMID:6417168
NASA Astrophysics Data System (ADS)
Martelloni, Gianluca; Bagnoli, Franco
2016-04-01
intense or long rain that percolates into the soil causing an increasing of the pore water pressure. In literature two type of models exist for attempting to forecast the landslides triggering: statistical or empirical modeling based on rainfall thresholds derived from the analysis of temporal series of daily rain [34] and geotechnical modeling, i.e., slope stability models that take into account water infiltration by rainfall considering classical Richardson equations [35-39]. Regarding the propagation of landslides, the models follow Eulerian (e.g., finite element methods, [40]) or Lagrangian approach (e.g., particle or molecular dynamics methods [41-46]). In a preliminary work [44], the possibility of the integration between fractional-based infiltration modeling and molecular dynamics approach, to model both the triggering and propagation, has been investigated in order to characterize the granular material varying the order of fractional derivative taking into account the equation -∂δ ∂2θ(z,t) ∂tδθ(z,t)=D ∂z2 , (6) where θ(z,t) represents the water content depending on time t and soil depth z [47], while the parameter δ, with 0.5 ≤ δ < 1, represents the fractional derivative order to consider anomalous sub-diffusion [48]; when δ = 1 we have classical derivative, i.e., normal diffusion, and when δ > 1 super-diffusion [32]. To sum up, in [44], a three-dimensional model is developed, the water content is expressed in term of pore pressure (interpreted as a scalar field acting on the particles), whose increasing induces the shear strength reduction. The latter is taking into account by means of Mohr-Coulomb criterion that represents a failure criterion based on limit equilibrium theory [49, 50]. Moreover, the fluctuations depending on positions, in term of pore pressure, are also considered. Concerning the interaction between particles, a Lennard-Jones potential is taking into account and other active forces as gravity, dynamic friction and viscosity
Quantification of sand fraction from seismic attributes using Neuro-Fuzzy approach
NASA Astrophysics Data System (ADS)
Verma, Akhilesh K.; Chaki, Soumi; Routray, Aurobinda; Mohanty, William K.; Jenamani, Mamata
2014-12-01
In this paper, we illustrate the modeling of a reservoir property (sand fraction) from seismic attributes namely seismic impedance, seismic amplitude, and instantaneous frequency using Neuro-Fuzzy (NF) approach. Input dataset includes 3D post-stacked seismic attributes and six well logs acquired from a hydrocarbon field located in the western coast of India. Presence of thin sand and shale layers in the basin area makes the modeling of reservoir characteristic a challenging task. Though seismic data is helpful in extrapolation of reservoir properties away from boreholes; yet, it could be challenging to delineate thin sand and shale reservoirs using seismic data due to its limited resolvability. Therefore, it is important to develop state-of-art intelligent methods for calibrating a nonlinear mapping between seismic data and target reservoir variables. Neural networks have shown its potential to model such nonlinear mappings; however, uncertainties associated with the model and datasets are still a concern. Hence, introduction of Fuzzy Logic (FL) is beneficial for handling these uncertainties. More specifically, hybrid variants of Artificial Neural Network (ANN) and fuzzy logic, i.e., NF methods, are capable for the modeling reservoir characteristics by integrating the explicit knowledge representation power of FL with the learning ability of neural networks. In this paper, we opt for ANN and three different categories of Adaptive Neuro-Fuzzy Inference System (ANFIS) based on clustering of the available datasets. A comparative analysis of these three different NF models (i.e., Sugeno-type fuzzy inference systems using a grid partition on the data (Model 1), using subtractive clustering (Model 2), and using Fuzzy c-means (FCM) clustering (Model 3)) and ANN suggests that Model 3 has outperformed its counterparts in terms of performance evaluators on the present dataset. Performance of the selected algorithms is evaluated in terms of correlation coefficients (CC), root
Sandoval, Santiago; Bertrand-Krajewski, Jean-Luc
2016-06-01
Total suspended solid (TSS) measurements in urban drainage systems are required for several reasons. Aiming to assess uncertainties in the mean TSS concentration due to the influence of sampling intake vertical position and vertical concentration gradients in a sewer pipe, two methods are proposed: a simplified method based on a theoretical vertical concentration profile (SM) and a time series grouping method (TSM). SM is based on flow rate and water depth time series. TSM requires additional TSS time series as input data. All time series are from the Chassieu urban catchment in Lyon, France (time series from 2007 with 2-min time step, 89 rainfall events). The probability of measuring a TSS value lower than the mean TSS along the vertical cross section (TSS underestimation) is about 0.88 with SM and about 0.64 with TSM. TSM shows more realistic TSS underestimation values (about 39 %) than SM (about 269 %). Interquartile ranges (IQR) over the probability values indicate that SM is more uncertain (IQR = 0.08) than TSM (IQR = 0.02). Differences between the two methods are mainly due to simplifications in SM (absence of TSS measurements). SM assumes a significant asymmetry of the TSS concentration profile along the vertical axis in the cross section. This is compatible with the distribution of TSS measurements found in the TSM approach. The methods provide insights towards an indicator of the measurement performance and representativeness for a TSS sampling protocol. PMID:27178049
NASA Astrophysics Data System (ADS)
Zhang, Xiaofen; Clements, M. A. (Ken); Ellerton, Nerida F.
2015-06-01
This study investigated how fifth-grade children's concept images of the unit fractions represented by the symbols , , and changed as a result of their participation in an instructional intervention based on multiple embodiments of fraction concepts. The participants' concept images were examined through pre- and post-teaching written questions and pre- and post-teaching one-to-one verbal interview questions. Results showed that at the pre-teaching stage, the student concept images of unit fractions were very narrow and mainly linked to area models. However, after the instructional intervention, the fifth graders were able to select and apply a variety of models in response to unit fraction tasks, and their concept images of unit fractions were enriched and linked to capacity, perimeter, linear and discrete models, as well as to area models. Their performances on tests had improved, and their conceptual understandings of unit fractions had developed.
Long-memory and the sea level-temperature relationship: a fractional cointegration approach.
Ventosa-Santaulària, Daniel; Heres, David R; Martínez-Hernández, L Catalina
2014-01-01
Through thermal expansion of oceans and melting of land-based ice, global warming is very likely contributing to the sea level rise observed during the 20th century. The amount by which further increases in global average temperature could affect sea level is only known with large uncertainties due to the limited capacity of physics-based models to predict sea levels from global surface temperatures. Semi-empirical approaches have been implemented to estimate the statistical relationship between these two variables providing an alternative measure on which to base potentially disrupting impacts on coastal communities and ecosystems. However, only a few of these semi-empirical applications had addressed the spurious inference that is likely to be drawn when one nonstationary process is regressed on another. Furthermore, it has been shown that spurious effects are not eliminated by stationary processes when these possess strong long memory. Our results indicate that both global temperature and sea level indeed present the characteristics of long memory processes. Nevertheless, we find that these variables are fractionally cointegrated when sea-ice extent is incorporated as an instrumental variable for temperature which in our estimations has a statistically significant positive impact on global sea level. PMID:25426638
Long-Memory and the Sea Level-Temperature Relationship: A Fractional Cointegration Approach
Ventosa-Santaulària, Daniel; Heres, David R.; Martínez-Hernández, L. Catalina
2014-01-01
Through thermal expansion of oceans and melting of land-based ice, global warming is very likely contributing to the sea level rise observed during the 20th century. The amount by which further increases in global average temperature could affect sea level is only known with large uncertainties due to the limited capacity of physics-based models to predict sea levels from global surface temperatures. Semi-empirical approaches have been implemented to estimate the statistical relationship between these two variables providing an alternative measure on which to base potentially disrupting impacts on coastal communities and ecosystems. However, only a few of these semi-empirical applications had addressed the spurious inference that is likely to be drawn when one nonstationary process is regressed on another. Furthermore, it has been shown that spurious effects are not eliminated by stationary processes when these possess strong long memory. Our results indicate that both global temperature and sea level indeed present the characteristics of long memory processes. Nevertheless, we find that these variables are fractionally cointegrated when sea-ice extent is incorporated as an instrumental variable for temperature which in our estimations has a statistically significant positive impact on global sea level. PMID:25426638
Liu, Y.; Wu, W.; Jensen, M. P.; Toto, T.
2011-07-21
This paper focuses on three interconnected topics: (1) quantitative relationship between surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo; (2) surface-based approach for measuring cloud albedo; (3) multiscale (diurnal, annual and inter-annual) variations and covariations of surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo. An analytical expression is first derived to quantify the relationship between cloud radiative forcing, cloud fraction, and cloud albedo. The analytical expression is then used to deduce a new approach for inferring cloud albedo from concurrent surface-based measurements of downwelling surface shortwave radiation and cloud fraction. High-resolution decade-long data on cloud albedos are obtained by use of this surface-based approach over the US Department of Energy's Atmospheric Radiaton Measurement (ARM) Program at the Great Southern Plains (SGP) site. The surface-based cloud albedos are further compared against those derived from the coincident GOES satellite measurements. The three long-term (1997-2009) sets of hourly data on shortwave cloud radiative forcing, cloud fraction and cloud albedo collected over the SGP site are analyzed to explore the multiscale (diurnal, annual and inter-annual) variations and covariations. The analytical formulation is useful for diagnosing deficiencies of cloud-radiation parameterizations in climate models.
ERIC Educational Resources Information Center
Zhang, Xiaofen; Clements, M. A.; Ellerton, Nerida F.
2015-01-01
This study investigated how fifth-grade children's concept images of the unit fractions represented by the symbols 1/2, 1/3/ and 1/4 changed as a result of their participation in an instructional intervention based on multiple embodiments of fraction concepts. The participants' concept images were examined through pre- and post-teaching written…
NASA Astrophysics Data System (ADS)
Jastrow, J. D.; Swanston, C. W.; O'Brien, S. L.; Moran, K. K.; Porras, R. C.; Torn, M. S.
2008-12-01
Efforts to isolate soil C pools related to the structure, function and turnover of soil organic matter (SOM) often employ physical fractionation methods. Both density-based and particle-size fractionations have been used to examine the role of aggregates in SOM cycling and stabilization. After a 14C pulse labeling of deciduous forest, reciprocal transplants of enriched vs. near-background litter allowed us to track the source and dynamics of SOM pools isolated by both fractionation approaches. Light fraction (LF) and particulate organic matter (POM) were separated into unprotected and aggregate-protected pools by applying different dispersion energies. The mineral-associated pool was characterized either as the dense fraction (DF) or as particles <53 μm (MOM). We used procedural constraints and the distributions of bulk soil C and 14C to compare pools isolated by each method. The uPOM fraction included both free and macroaggregate-associated particulate C pools, whereas the free LF isolated mostly unprotected, interstitial particulate C. Operationally, the mPOM fraction consisted of microaggregate-protected particulate C, but the occluded LF included both macroaggregate-associated and microaggregate-protected C. Overall, POM accounted for 5% more of bulk soil C than LF, with the difference likely due to inclusion of some microaggregate-protected particulate C in the DF. POM/LF-C dynamics associated with root turnover occurred mostly at the macroaggregate rather than the microaggregate scale during the 4-y study. In contrast, the dynamics of litter C sources occurred at both scales suggesting a different mode of incorporation, e.g., sorption of soluble C to exchange sites or assimilation by microbes associated with the POM/LF. Acid hydrolysis of the MOM fraction revealed dynamic components that rapidly incorporated and cycled C inputs from both root and litter sources. Taken together, the results improve our understanding of short-term soil C dynamics and the C
Fractional-order elastic models of cartilage: A multi-scale approach
NASA Astrophysics Data System (ADS)
Magin, Richard L.; Royston, Thomas J.
2010-03-01
The objective of this research is to develop new quantitative methods to describe the elastic properties (e.g., shear modulus, viscosity) of biological tissues such as cartilage. Cartilage is a connective tissue that provides the lining for most of the joints in the body. Tissue histology of cartilage reveals a multi-scale architecture that spans a wide range from individual collagen and proteoglycan molecules to families of twisted macromolecular fibers and fibrils, and finally to a network of cells and extracellular matrix that form layers in the connective tissue. The principal cells in cartilage are chondrocytes that function at the microscopic scale by creating nano-scale networks of proteins whose biomechanical properties are ultimately expressed at the macroscopic scale in the tissue's viscoelasticity. The challenge for the bioengineer is to develop multi-scale modeling tools that predict the three-dimensional macro-scale mechanical performance of cartilage from micro-scale models. Magnetic resonance imaging (MRI) and MR elastography (MRE) provide a basis for developing such models based on the nondestructive biomechanical assessment of cartilage in vitro and in vivo. This approach, for example, uses MRI to visualize developing proto-cartilage structure, MRE to characterize the shear modulus of such structures, and fractional calculus to describe the dynamic behavior. Such models can be extended using hysteresis modeling to account for the non-linear nature of the tissue. These techniques extend the existing computational methods to predict stiffness and strength, to assess short versus long term load response, and to measure static versus dynamic response to mechanical loads over a wide range of frequencies (50-1500 Hz). In the future, such methods can perhaps be used to help identify early changes in regenerative connective tissue at the microscopic scale and to enable more effective diagnostic monitoring of the onset of disease.
Itu, Lucian; Rapaka, Saikiran; Passerini, Tiziano; Georgescu, Bogdan; Schwemmer, Chris; Schoebinger, Max; Flohr, Thomas; Sharma, Puneet; Comaniciu, Dorin
2016-07-01
Fractional flow reserve (FFR) is a functional index quantifying the severity of coronary artery lesions and is clinically obtained using an invasive, catheter-based measurement. Recently, physics-based models have shown great promise in being able to noninvasively estimate FFR from patient-specific anatomical information, e.g., obtained from computed tomography scans of the heart and the coronary arteries. However, these models have high computational demand, limiting their clinical adoption. In this paper, we present a machine-learning-based model for predicting FFR as an alternative to physics-based approaches. The model is trained on a large database of synthetically generated coronary anatomies, where the target values are computed using the physics-based model. The trained model predicts FFR at each point along the centerline of the coronary tree, and its performance was assessed by comparing the predictions against physics-based computations and against invasively measured FFR for 87 patients and 125 lesions in total. Correlation between machine-learning and physics-based predictions was excellent (0.9994, P < 0.001), and no systematic bias was found in Bland-Altman analysis: mean difference was -0.00081 ± 0.0039. Invasive FFR ≤ 0.80 was found in 38 lesions out of 125 and was predicted by the machine-learning algorithm with a sensitivity of 81.6%, a specificity of 83.9%, and an accuracy of 83.2%. The correlation was 0.729 (P < 0.001). Compared with the physics-based computation, average execution time was reduced by more than 80 times, leading to near real-time assessment of FFR. Average execution time went down from 196.3 ± 78.5 s for the CFD model to ∼2.4 ± 0.44 s for the machine-learning model on a workstation with 3.4-GHz Intel i7 8-core processor. PMID:27079692
First-passage time for subdiffusion: The nonadditive entropy approach versus the fractional model
NASA Astrophysics Data System (ADS)
Kosztołowicz, Tadeusz; Lewandowska, Katarzyna D.
2012-08-01
We study the similarities and differences between different models concerning subdiffusion. More particularly, we calculate first passage time (FPT) distributions for subdiffusion, derived from Greens’ functions of nonlinear equations obtained from Sharma-Mittal's, Tsallis's, and Gauss's nonadditive entropies. Then we compare these with FPT distributions calculated from a fractional model using a subdiffusion equation with a fractional time derivative. All of Greens’ functions give us exactly the same standard relation <(Δx)2>=2Dαtα which characterizes subdiffusion (0<α<1), but generally FPT distributions are not equivalent to one another. We will show here that the FPT distribution for the fractional model is asymptotically equal to the Sharma-Mittal model over the long time limit only if in the latter case one of the three parameters describing Sharma-Mittal entropy r depends on α, and satisfies the specific equation derived in this paper, whereas the other two models mentioned above give different FPT distributions with the fractional model. Greens’ functions obtained from the Sharma-Mittal and fractional models, for r obtained from this particular equation, are very similar to each other. We will also discuss the interpretation of subdiffusion models based on nonadditive entropies and the possibilities of the experimental measurement of subdiffusion models’ parameters.
Estimating the hatchery fraction of a natural population: a Bayesian approach
Barber, Jarrett J.; Gerow, Kenneth G.; Connolly, Patrick J.; Singh, Sarabdeep
2011-01-01
There is strong and growing interest in estimating the proportion of hatchery fish that are in a natural population (the hatchery fraction). In a sample of fish from the relevant population, some are observed to be marked, indicating their origin as hatchery fish. The observed proportion of marked fish is usually less than the actual hatchery fraction, since the observed proportion is determined by the proportion originally marked, differential survival (usually lower) of marked fish relative to unmarked hatchery fish, and rates of mark retention and detection. Bayesian methods can work well in a setting such as this, in which empirical data are limited but for which there may be considerable expert judgment regarding these values. We explored a Bayesian estimation of the hatchery fraction using Monte Carlo–Markov chain methods. Based on our findings, we created an interactive Excel tool to implement the algorithm, which we have made available for free.
Giacomino, A; Malandrino, M; Abollino, O; Velayutham, M; Chinnathangavel, T; Mentasti, E
2010-02-01
The fractionation and speciation of As in a contaminated soil were investigated, and a remediation strategy was tested. Regarding speciation, we found that As(V) prevails over As(III) whereas more than 40% of total arsenic is in organic form. The fractionation of As was investigated with two sequential extraction methods: a low mobility was found. Then we tested the possibility of using phosphoric acid to extract As from the soil and cleaning the washing effluents by sorption onto montmorillonite. The efficiency of the extraction and of the adsorption onto the clay were also investigated for Cr, Cu, Fe, Mn, Ni, Pb and Zn, whose total concentrations and fractionation in the soil are reported here. The extraction percentages for As and metals ranged from 30 to 65%; the residual proportions in the soil are presumably in very unreactive forms. Montmorillonite showed a good uptake capacity towards the investigated pollutants. PMID:19783338
Garonzik, Samira M.; Lenhard, Justin R.; Forrest, Alan; Holden, Patricia N.; Bulitta, Jϋrgen B.; Tsuji, Brian T.
2016-01-01
Our objective was to study the pharmacodynamics of daptomycin in the presence of varying concentrations of human serum (HS) in vitro to quantify the fraction of daptomycin that is ‘active’. Time kill experiments were performed with daptomycin (0 to 256 mg/L) against two MRSA strains at log-phase growth, in the presence of HS (0%, 10%, 30%, 50%, 70%) combined with Mueller-Hinton broth. Daptomycin ≥ 2 mg/L achieved 99.9% kill within 8 h at all HS concentrations; early killing activity was slightly attenuated at higher HS concentrations. After 1 h, bacterial reduction of USA300 upon exposure to daptomycin 4 mg/L ranged from -3.1 to -0.5 log10CFU/mL in the presence of 0% to 70% HS, respectively. Bactericidal activity was achieved against both strains at daptomycin ≥ 4 mg/L for all fractions of HS exposure. A mechanism-based mathematical model (MBM) was developed to estimate the active daptomycin fraction at each %HS, comprising 3 bacterial subpopulations differing in daptomycin susceptibility. Time-kill data were fit with this MBM with excellent precision (r2 >0.95). The active fraction of daptomycin was estimated to range from 34.6% to 25.2% at HS fractions of 10% to 70%, respectively. Despite the reported low unbound fraction of daptomycin, the impact of protein binding on the activity of daptomycin was modest. The active fraction approach can be utilized to design in vitro experiments and to optimize therapeutic regimens of daptomycin in humans. PMID:27284923
Technology Transfer Automated Retrieval System (TEKTRAN)
Calorie restriction (CR) is a component of most weight-loss interventions and a potential strategy to slow aging. Accurate determination of energy intake and %CR is critical when interpreting the results of CR interventions; this is best achieved using the doubly labeled water method to quantify tot...
A Predictor-Corrector Approach for the Numerical Solution of Fractional Differential Equations
NASA Technical Reports Server (NTRS)
Diethelm, Kai; Ford, Neville J.; Freed, Alan D.; Gray, Hugh R. (Technical Monitor)
2002-01-01
We discuss an Adams-type predictor-corrector method for the numerical solution of fractional differential equations. The method may be used both for linear and for nonlinear problems, and it may be extended to multi-term equations (involving more than one differential operator) too.
Cook, D E; Bender, R W; Shinners, K J; Combs, D K
2016-07-01
The objective of this trial was to evaluate, in dairy cattle, the effects of calcium hydroxide treatment of whole-plant corn and a treatment applied to the bottom stalk fraction of the corn plant, achieved by harvesting corn in 2 crop streams. The treatments were calcium hydroxide-treated corn silage (TRTCS), toplage supplemented with calcium hydroxide-treated stalklage (TPL), a positive control of brown midrib corn silage (BMR), and a negative control of conventional whole-plant corn silage (WPCS). The toplage was harvested at a height of 82 cm with 2 of the 6 rows set as ear-snapping to incorporate higher tissues into the stalklage. Stalklage was harvested at 12 cm, and other corn silages were harvested at 27 cm. Sixteen pens, each with 8 Holstein cows averaging 70±25 d in milk and 46±11 kg of milk d(-1), were assigned 4 per treatment in a completely randomized design. The diet was approximately 40% corn silage, 20% alfalfa silage, and 40% concentrate on a dry matter basis. A 2-wk covariate period with conventional corn silage was followed by an 8-wk treatment period in which the 4 corn silage treatments were the only effective difference in diets. Cows fed TPL and TRTCS consumed more (1.9 and 1.4 kg of organic matter d(-1), respectively) than did cows fed WPCS. Milk yield was greater for cows fed BMR, TPL, and TRTCS. Cows fed BMR and TPL produced 2.9 and 2.7 kg d(-1), respectively, more energy-corrected milk (ECM) than cows fed WPCS, and cows fed TRTCS had the greatest ECM production (4.8 kg of ECM d(-1) greater than cows fed WPCS). No differences in body weight or body condition scored were observed. Milk fat concentration was similar among treatments and milk protein concentration was reduced for TRTCS. Starch and neutral detergent fiber digestibility were greater for cows fed TRTCS. PMID:27157570
NASA Astrophysics Data System (ADS)
Man, Yiu-Kwong
2012-10-01
Partial fraction decomposition is a useful technique often taught at senior secondary or undergraduate levels to handle integrations, inverse Laplace transforms or linear ordinary differential equations, etc. In recent years, an improved Heaviside's approach to partial fraction decomposition was introduced and developed by the author. An important feature of this approach is that there is no need to solve a system of linear equations or to use differentiations to find the unknown coefficients of the partial fractions. In order to study its potential application in mathematics education at the undergraduate level, a pilot study of tryout at the Hong Kong Institute of Education has been conducted. The data are collected via quizzes, questionnaires and face-to-face interviews. In this article, the results and implications will be discussed. In general, according to the responses and feedbacks from the instructors and students concerned, the improved Heaviside approach is suitable to be introduced at the undergraduate level, as an alternative to the method of undetermined coefficients described in common undergraduate mathematics textbooks.
Study of the regional CO2 mole fractions filtering approach at a WMO/GAW regional station in China
NASA Astrophysics Data System (ADS)
Fang, S. X.; Tans, P. P.; Steinbacher, M.; Zhou, L. X.; Luan, T.
2015-07-01
The identification of atmospheric CO2 observation data which is minimally influenced by very local emissions/removals is essential for the estimation of trend analysis, regional sources and sinks, and for modeling of long-range transport of CO2. In this study, four approaches are used to filter the atmospheric CO2 observation records from 2009 to 2011 at one World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station (Lin'an, LAN) in China. The methods are based on the atmospheric black carbon concentration (BC), on a statistical approach (REBS), on CH4 as auxiliary tracer (AUX) and on meteorological parameters (MET). All approaches do suitably well to capture the seasonal CO2 cycle at LAN. Differences are observed in the average regional mole fractions with annual values in the REBS method at least 1.7 ± 0.2 ppm higher than the other methods. The BC method may underestimate the regional CO2 mole fractions during winter-spring period and should be treated with caution. The REBS method is a purely statistical method and it may also introduce errors on the regional CO2 mole fractions evaluations, as the filtered trend may be deviated by the "noisy" raw data series. Although there are correlations between CH4 and CO2 mole fractions at LAN, the different source/sink regimes may introduce bias on the regional CO2 estimation in the AUX method, typically in summer. Overall, the MET method seems to be the most favorable because it mainly focuses on the influence of potential local sources and sinks and considers diurnal variations, local topography, and meteorological conditions. Using the MET method, the annual growth rate of regional CO2 at LAN is determined to be 3.1 ± 0.01 ppm yr-1 (standard error) from 2009 to 2013.
NASA Astrophysics Data System (ADS)
Fang, S. X.; Tans, P. P.; Steinbacher, M.; Zhou, L. X.; Luan, T.
2015-12-01
The identification of atmospheric CO2 observation data which are minimally influenced by very local emissions/removals is essential for trend analysis, for the estimation of regional sources and sinks, and for the modeling of long-range transport of CO2. In this study, four approaches are used to filter the atmospheric CO2 observation records from 2009 to 2011 at one World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station (Lin'an, LAN) in China. The methods are based on the concentration of atmospheric black carbon (BC), on a statistical approach (robust extraction of baseline signal, REBS), on CH4 as an auxiliary tracer (AUX), and on meteorological parameters (MET). All approaches do suitably well to capture the seasonal CO2 cycle at LAN. Differences are observed in the average regional mole fractions with annual values in the REBS method at least 1.7 ± 0.2 ppm higher than the other methods. The BC method may underestimate the regional CO2 mole fractions during the winter-spring period and should be treated with caution. The REBS method is a purely statistical method and it may also introduce errors on the regional CO2 mole fraction evaluations, as the filtered trend may be influenced by the "noisy" raw data series. Although there are correlations between CH4 and CO2 mole fractions at LAN, the different source/sink regimes may introduce bias on the regional CO2 estimation in the AUX method, typically in summer. Overall, the MET method seems to be the most favorable because it mainly focuses on the influence of potential local sources and sinks, and considers diurnal variations and meteorological conditions. Using the MET method, the annual growth rate of regional CO2 at LAN is determined to be 3.1 ± 0.01 ppm yr-1 (standard error) from 2009 to 2011.
Hoyer, Andrea B; Schladow, S Geoffrey; Rueda, Francisco J
2015-10-15
Pathogen contamination of drinking water lakes and reservoirs is a severe threat to human health worldwide. A major source of pathogens in surface sources of drinking waters is from body-contact recreation in the water body. However, dispersion pathways of human waterborne pathogens from recreational beaches, where body-contact recreation is known to occur to drinking water intakes, and the associated risk of pathogens entering the drinking water supply remain largely undocumented. A high spatial resolution, three-dimensional hydrodynamic and particle tracking modeling approach has been developed to analyze the risk and mechanisms presented by pathogen dispersion. The pathogen model represents the processes of particle release, transport and survival. Here survival is a function of both water temperature and cumulative exposure to ultraviolet (UV) radiation. Pathogen transport is simulated using a novel and computationally efficient technique of tracking particle trajectories backwards, from a drinking water intake toward their source areas. The model has been applied to a large, alpine lake - Lake Tahoe, CA-NV (USA). The dispersion model results reveal that for this particular lake (1) the risk of human waterborne pathogens to enter drinking water intakes is low, but significant; (2) this risk is strongly related to the depth of the thermocline in relation to the depth of the intake; (3) the risk increases with the seasonal deepening of the surface mixed layer; and (4) the risk increases at night when the surface mixed layer deepens through convective mixing and inactivation by UV radiation is eliminated. While these risk factors will quantitatively vary in different lakes, these same mechanisms will govern the process of transport of pathogens. PMID:26162312
Conformational effect of dicyclo-hexano-18-crown-6 on isotopic fractionation of zinc: DFT approach
Boda, A.; Singha Deb, A. K.; Ali, Sk. M.; Shenoy, K. T.; Ghosh, S. K.
2014-04-24
Generalized gradient approximated BP86 density functional employing triple zeta valence plus polarization (TZVP) basis set has been used to compute the reduced partition function ratio and isotopic separation factor for zinc isotopes. The isotopic separation factor was found to be in good agreement with the experimental results. The isotopic separation factor was found to depend on the conformation of the crown ether ligand. The trans-trans conformation shows the highest fractionation compared to cis-cis conformer. The present theoretical results can thus be used to plan the isotope separation experiments.
Mellin transform approach for the solution of coupled systems of fractional differential equations
NASA Astrophysics Data System (ADS)
Butera, Salvatore; Di Paola, Mario
2015-01-01
In this paper, the solution of a multi-order, multi-degree-of-freedom fractional differential equation is addressed by using the Mellin integral transform. By taking advantage of a technique that relates the transformed function, in points of the complex plane differing in the value of their real part, the solution is found in the Mellin domain by solving a linear set of algebraic equations. The approximate solution of the differential (or integral) equation is restored, in the time domain, by using the inverse Mellin transform in its discretized form.
NASA Astrophysics Data System (ADS)
Martelloni, Gianluca; Bagnoli, Franco
2016-04-01
In the past three decades, fractional and fractal calculus (that is, calculus of derivatives and integral of any arbitrary real or complex order) appeared to be an important tool for its applications in many fields of science and engineering. This theory allows to face, analytically and/or numerically, fractional differential equations and fractional partial differential equations. In particular, one of the several applications deals with anomalous diffusion processes. The latter phenomena can be clearly described from the statistical viewpoint. Indeed, in various complex systems, the diffusion processes usually no longer follow Gaussian statistics, and thus Fick's second law fails to describe the related transport behavior. In particular, one observes deviations from the linear time dependence of the mean squared displacement ⟨x2(t)⟩ ∝ t, (1) which is characteristic of Brownian motion, i.e., a direct consequence of the central limit theorem and the Markovian nature of the underlying stochastic process [1-17]. Instead, anomalous diffusion is found in a wide diversity of systems and its feature is the non-linear growth of the mean squared displacement over time. Especially the power-law pattern, with exponent γ different from 1 ⟨ ⟩ x2(t) ∝ tγ, (2) characterizes many systems [18, 19], but a variety of other rules, such as a logarithmic time dependence, exist [20]. The anomalous diffusion, as expressed in Eq. (2) is connected with the breakdown of the central limit theorem, caused by either broad distributions or long-range correlations, e.g., the extreme statistics and the power law distributions, typical of the self-organized criticality [42, 43]. Instead, anomalous diffusion rests on the validity of the Levy-Gnedenko generalized central limit theorem [21-23]. Particularly, broad spatial jumps or waiting time distributions lead to non-Gaussian distribution and non-Markovian time evolution of the system. Anomalous diffusion has been known since
A novel fractionation approach for water constituents – distribution of storm event metals
McKenzie, Erica R.; Young, Thomas M.
2014-01-01
A novel fractionation method, based on both particle size and settling characteristics, was employed to examine metal distributions among five fractions. In-stream and stormwater runoff samples were collected from four land use types: highway, urban, agricultural (storm event and irrigation), and natural. Highway samples contained the highest dissolved concentrations for most metals, and freshwater ambient water quality criteria were exceeded for Cd, Cu, Pb, and Zn in the first storm of the water year. Anthropogenic sources were indicated for Cu, Zn, Cd, and Pb in highway and urban samples, and total metal loadings (mg/km2) were observed to be as follows: highway > urban > agricultural storm event ~ natural > agricultural irrigation. Notably, ~10-fold higher suspended solids concentration was observed in the agricultural storm event sample, and suspended solids-associated metals were correspondingly elevated. Distribution coefficients revealed the following affinities: Zn, Ni, Cd, and Pb to large dense particles; and Cu, Zn, Cr, Ni, and Pb to colloidal organic matter. PMID:23535891
NASA Astrophysics Data System (ADS)
Mukherjee, Sutirtha; Mandal, Sudhansu
The internal structure and topology of the ground states for fractional quantum Hall effect (FQHE) are determined by the relative angular momenta between all the possible pairs of electrons. Laughlin wave function is the only known microscopic wave function for which these relative angular momenta are homogeneous (same) for any pair of electrons and depend solely on the filling factor. Without invoking any microscopic theory, considering only the relationship between number of flux quanta and particles in spherical geometry, and allowing the possibility of inhomogeneous (different) relative angular momenta between any two electrons, we develop a general method for determining a closed-form ground state wave function for any incompressible FQHE state. Our procedure provides variationally obtained very accurate wave functions, yet having simpler structure compared to any other known complex microscopic wave functions for the FQHE states. This method, thus, has potential in predicting a very accurate ground state wave function for the puzzling states such as the state at filling fraction 5/2. We acknowledge support from Department of Science and Technology, India.
Krämer, P; Wincierz, U; Grübler, G; Tschakert, J; Voelter, W; Mayer, H
1995-06-01
Polysaccharides, isolated from the lichen Cetraria islandica, have antimicrobial effectiveness. For pharmaceutical applications the two glucan components lichenan and isolichenan as well as the galactomannan component are of actual interest. Especially the a-glucan isolichenan ist used as an active ingredient in cough lozenges. The conditions for the extraction of the raw material, mainly pH and temperature, have a strong influence on the yield of lichenan, isolichenan, and galactomannan, and also on the amount of tannins in the extract. Target products and also by-products give higher extraction yields with increasing extraction temperatures. Hot water extraction with subsequent fractionation of the extracted polysaccharides by multiple freezing/thawing steps and water removal applying ethanol and ether permitted the isolation of the target polysaccharides in preparative quantities. Tannins were removed by reversed phase chromatography. IR and NMR spectroscopy were used for structural characterization of lichenan and isolichenan. After optimization of the hot water extraction process no significant lower extraction and fractionation yields have been obtained compared to the established tricky DMSO extraction procedure. PMID:7646581
Revisited Fisher's equation in a new outlook: A fractional derivative approach
NASA Astrophysics Data System (ADS)
Alquran, Marwan; Al-Khaled, Kamel; Sardar, Tridip; Chattopadhyay, Joydev
2015-11-01
The well-known Fisher equation with fractional derivative is considered to provide some characteristics of memory embedded into the system. The modified model is analyzed both analytically and numerically. A comparatively new technique residual power series method is used for finding approximate solutions of the modified Fisher model. A new technique combining Sinc-collocation and finite difference method is used for numerical study. The abundance of the bird species Phalacrocorax carbois considered as a test bed to validate the model outcome using estimated parameters. We conjecture non-diffusive and diffusive fractional Fisher equation represents the same dynamics in the interval (memory index, α ∈(0.8384 , 0.9986)). We also observe that when the value of memory index is close to zero, the solutions bifurcate and produce a wave-like pattern. We conclude that the survivability of the species increases for long range memory index. These findings are similar to Fisher observation and act in a similar fashion that advantageous genes do.
FRACTIONAL CRYSTALLIZATION OF HANFORD SINGLE SHELL TANK (SST) WASTES A MODELING APPROACH
HAMILTON, D.W.
2006-12-21
The Hanford site has 149 underground single-shell tanks (SST) storing mostly soluble, multi-salt, mixed wastes resulting from Cold War era weapons material production. These wastes must be retrieved and the salts immobilized before the tanks can be closed to comply with an overall site closure consent order entered into by the U.S. Department of Energy (DOE), the Environmental Protection Agency, and Washington State. Water will be used to retrieve the wastes and the resulting solution will be pumped to the proposed treatment process where a high curie (primarily {sup 137}Cs) waste fraction will be separated from the other waste constituents. The separated waste streams will then be vitrified to allow for safe storage as an immobilized high level waste, or low level waste, borosilicate glass. Fractional crystallization, a common unit operation for production of industrial chemicals and pharmaceuticals, was proposed as the method to separate the salt wastes; it works by evaporating excess water until the solubilities of various species in the solution are exceeded (the solubility of a particular species depends on its concentration, temperature of the solution, and the presence of other ionic species in the solution). By establishing the proper conditions, selected pure salts can be crystallized and separated from the radioactive liquid phase.
Yao, C; Spurlock, D M; Armentano, L E; Page, C D; VandeHaar, M J; Bickhart, D M; Weigel, K A
2013-10-01
Feed efficiency is an economically important trait in the beef and dairy cattle industries. Residual feed intake (RFI) is a measure of partial efficiency that is independent of production level per unit of body weight. The objective of this study was to identify significant associations between single nucleotide polymorphism (SNP) markers and RFI in dairy cattle using the Random Forests (RF) algorithm. Genomic data included 42,275 SNP genotypes for 395 Holstein cows, whereas phenotypic measurements were daily RFI from 50 to 150 d postpartum. Residual feed intake was defined as the difference between an animal's feed intake and the average intake of its cohort, after adjustment for year and season of calving, year and season of measurement, age at calving nested within parity, days in milk, milk yield, body weight, and body weight change. Random Forests is a widely used machine-learning algorithm that has been applied to classification and regression problems. By analyzing the tree structures produced within RF, the 25 most frequent pairwise SNP interactions were reported as possible epistatic interactions. The importance scores that are generated by RF take into account both main effects of variables and interactions between variables, and the most negative value of all importance scores can be used as the cutoff level for declaring SNP effects as significant. Ranking by importance scores, 188 SNP surpassed the threshold, among which 38 SNP were mapped to RFI quantitative trait loci (QTL) regions reported in a previous study in beef cattle, and 2 SNP were also detected by a genome-wide association study in beef cattle. The ratio of number of SNP located in RFI QTL to the total number of SNP in the top 188 SNP chosen by RF was significantly higher than in all 42,275 whole-genome markers. Pathway analysis indicated that many of the top 188 SNP are in genomic regions that contain annotated genes with biological functions that may influence RFI. Frequently occurring
Potential of calcium isotopes to identify fractionations in vegetation: experimental approach
NASA Astrophysics Data System (ADS)
Cobert, F.; Schmitt, A.; Bourgade, P.; Stille, P.; Chabaux, F. J.; Badot, P.; Jaegler, T.
2010-12-01
This study aims to better understand the role of vegetation on the Ca cycle at the level of the critical zone of the Earth, in order to specify the mechanisms controlling the Ca absorption by plants at the rock/plant interface. To do this, we performed experiments using hydroponic plant cultures in a way that we could control the cooccuring geochemical and biological processes and determine the impact of the nutritive solution on the Ca cycle within plants. A dicotyledon and calcicole plant with rapid growth, the French bean (Phaseolus vulgaris L.), has been chosen to have access to one complete growth cycle. Several experiments have been conducted with two Ca concentrations, 5 (L) and 60 (H) ppm and two pH values (4 and 6) in the nutritive solution, for which the Ca concentration was maintained constant, so its Ca content is considered to be infinite. We determined Ca concentrations and isotopic ratios in the nutritive solution and in different organs (main roots, secondary roots, old and young stems, old and young leaves and fruits) at two different growth stages (10 days and 6 weeks). Our results show, in accord with previously published field studies, that the bean organs are all enriched in the light 40Ca isotope compared to the nutritive solution (e.g. Wigand et al., 2005; Page et al., 2008; Cenki-Tok et al., 2009; Holmden and Bélanger, 2010). We identify two fractionation levels. The first occurs during the uptake of the nutrient elements by the lateral roots. This implies that the main mechanisms of light isotope enrichments in the plant are due to electrochemical gradient transport processes taking place at this interface. The second fractionation can be observed within the plant itself and is due to the nature of the considered organ itself. Indeed structural reservoirs (primary roots, stem, reproductive organs) incorporate more the light 40Ca isotope compared to the transfer reservoirs (lateral roots, xylem sap, leaves). This could be linked to ion
NASA Astrophysics Data System (ADS)
Cui, Liang; Li, Yongping; Huang, Guohe
2016-06-01
A double-sided fuzzy chance-constrained fractional programming (DFCFP) method is developed for planning water resources management under uncertainty. In DFCFP the system marginal benefit per unit of input under uncertainty can also be balanced. The DFCFP is applied to a real case of water resources management in the Zhangweinan River Basin, China. The results show that the amounts of water allocated to the two cities (Anyang and Handan) would be different under minimum and maximum reliability degrees. It was found that the marginal benefit of the system solved by DFCFP is bigger than the system benefit under the minimum and maximum reliability degrees, which not only improve economic efficiency in the mass, but also remedy water deficiency. Compared with the traditional double-sided fuzzy chance-constrained programming (DFCP) method, the solutions obtained from DFCFP are significantly higher, and the DFCFP has advantages in water conservation.
Albro, P W; Parker, C E
1980-09-19
Among the "inadvertent" environmental pollutants are polychlorinated biphenyls, terphenyls, quadphenyls, naphthalenes, diphenyl ethers, dibenzofurans, dibenzo-p-dioxins and benzenes. Mixtures of these classes of compounds also occur in commercial products such as transformer fluids. To analyze such mixtures, gas chromatography--mass spectrometry may be combined with pre-fractionation on basic and acidic alumina columns and semi-quantitative perchlorination techniques. These procedures are illustrated for synthetic mixtures as well as for two samples of stored transformer fluid. Although the described procedure is mainly intended to be applied to the characterization of the major class components of such mixtures, it is also applicable to the determination of trace components such as the dibenzofurans in commercial polychlorinated biphenyls. The mass spectral techniques permit the simultaneous patterning, or "fingerprinting", of the compounds comprising each major class of chlorinated aromatics present. PMID:7451593
Condition-based diagnosis of mechatronic systems using a fractional calculus approach
NASA Astrophysics Data System (ADS)
Gutiérrez-Carvajal, Ricardo Enrique; Flávio de Melo, Leonimer; Maurício Rosário, João; Tenreiro Machado, J. A.
2016-07-01
While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model's complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.
NASA Astrophysics Data System (ADS)
Kosztołowicz, Tadeusz; Lewandowska, Katarzyna
2012-06-01
We consider here two different models describing subdiffusion. One of them is derived from Continuous Time Random Walk formalism and utilizes a subdiffusion equation with a fractional time derivative. The second model is based on Sharma-Mittal nonadditive entropy formalism where the subdiffusive process is described by a nonlinear equation with ordinary derivatives. Using these two models we describe the process of a substance released from a thick membrane and we find functions which determine the time evolution of the amount of substance remaining inside this membrane. We then find `the agreement conditions' under which these two models provide the same relation defining subdiffusion and give the same function characterizing the process of the released substance. These agreement conditions enable us to determine the relation between the parameters occuring in both models.
A Physiographic Approach to Downscaling Remotely Sensed Fractional Snow Cover Data
NASA Astrophysics Data System (ADS)
Walters, R. D.; Watson, K. A.; Flores, A. N.
2012-12-01
Improved characterization of hydrologic states like soil moisture and snow water equivalent at scales of individual hillslopes (i.e., 10s to 100s of meters) would substantially benefit applications ranging from flood-forecasting to military trafficability assessment. In seasonally snow-covered mountain watersheds, complex topography influences the evolution of areal snow cover. Various satellite remote sensing data are able to capture the extent of snow covered area with spatial or temporal limitations depending on the particular product. For instance, the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, aboard Terra and Aqua satellites, produces fractional snow covered area (fSCA) grids daily but with 500-m spatial resolution. Conversely, the Landsat system can estimate binary snow cover at 30-m spacing but only on a 16-day return interval. Since variable snow ablation occurs within these spatiotemporal boundaries, it is desirable to estimate the snow cover at higher resolution. Here we propose a simple method to downscale daily MODIS fSCA data to 30-m resolution binary snow cover estimates. The algorithm computes a terrain score as a linear weighted average of two physiographic variables: elevation and relative insolation slope factor. Shuttle Radar Topography Mission (SRTM) data (30-m, co-registered with Landsat) are used to extract the elevation and to compute the radiation data. Under the assumption that low-elevation and high-insolation pixels will have melted first in an ephemeral snowpack, cells within each MODIS window are assigned a binary snow cover classification such that the fSCA observation is satisfied. Terrain score weights are optimized according to historical Landsat scenes within regions of southwestern Idaho. Blind test results in the same regions show good model performance (< 10%) when MODIS and Landsat are in agreement regarding snow cover fraction. The model is thus at the mercy of fSCA accuracy and may not perform as well when
A novel approach to improve operation and performance in flow field-flow fractionation.
Johann, Christoph; Elsenberg, Stephan; Roesch, Ulrich; Rambaldi, Diana C; Zattoni, Andrea; Reschiglian, Pierluigi
2011-07-01
A new system design and setup are proposed for the combined use of asymmetrical flow field-flow fractionation (AF4) and hollow-fiber flow field-flow fractionation (HF5) within the same instrumentation. To this purpose, three innovations are presented: (a) a new flow control scheme where focusing flow rates are measured in real time allowing to adjust the flow rate ratio as desired; (b) a new HF5 channel design consisting of two sets of ferrule, gasket and cap nut used to mount the fiber inside a tube. This design provides a mechanism for effective and straightforward sealing of the fiber; (c) a new AF4 channel design with only two fluid connections on the upper plate. Only one pump is needed to deliver the necessary flow rates. In the focusing/relaxation step the two parts of the focusing flow and a bypass flow flushing the detectors are created with two splits of the flow from the pump. In the elution mode the cross-flow is measured and controlled with a flow controller device. This leads to reduced pressure pulsations in the channel and improves signal to noise ratio in the detectors. Experimental results of the separation of bovine serum albumin (BSA) and of a mix of four proteins demonstrate a significant improvement in the HF5 separation performance, in terms of efficiency, resolution, and run-to-run reproducibility compared to what has been reported in the literature. Separation performance in HF5 mode is shown to be comparable to the performance in AF4 mode using a channel with two connections in the upper plate. PMID:21227436
Tran, Thanh-Nga Trinh; Hoang, Minh Van; Phan, Quynh-Anh Ngoc; Phung, Thuy L; Purschke, Martin; Ferinelli, William A; Sabir, Sameer; Ziegler, Andrew; Nelson, Stuart; Anderson, R Rox
2015-03-01
Radiation injury to the skin is a major source of dysfunction, disfigurement, and complications for thousands of patients undergoing adjunctive treatment for internal cancers. Despite the great potential for affecting quality of life, radiation injury has received little attention from dermatologists and is primarily being managed by radiation oncologists. During our volunteer work in Vietnam, we encountered numerous children with significant scarring and depigmentation of skin from the outdated use of radioactive phosphorus P32 in the treatment of hemangiomas. This dangerous practice has left thousands of children with significant fibrosis and disfigurement. Currently, there is no treatment for radiation dermatitis. Here, we report a case series using the combination of laser treatment, including pulsed-dye laser, fractional CO2 laser, and epidermal grafting to improve the appearance and function of the radiation scars in these young patients. We hope that by improving the appearance and function of these scars, we can improve the quality of life for these young patients and potentially open up a new avenue of treatment for cancer patients affected with chronic radiation dermatitis, potentially improving their range of motion, cosmesis, and reducing their risk of secondary skin malignancies. PMID:25922957
Turner-McGrievy, Gabrielle M; Wirth, Michael D; Shivappa, Nitin; Wingard, Ellen E; Fayad, Raja; Wilcox, Sara; Frongillo, Edward A; Hébert, James R
2015-02-01
Studies have examined nutrient differences among people following different plant-based diets. However, all of these studies have been observational. The aim of the present study was to examine differences in nutrient intake and Dietary Inflammatory Index (DII) scores among overweight and obese (body mass index 25.0-49.9 kg/m(2)) adults randomized to receive dietary instruction on a vegan (n = 12), vegetarian (n = 13), pescovegetarian (n = 13), semivegetarian (n = 13), or omnivorous (n = 12) diet during a 6-month randomized controlled trial. Nutrient intake, nutrient adequacy, and DII score were assessed via two 24-hour dietary recalls (Automated Self-Administered 24-Hour Dietary Recall) at baseline and at 2 and 6 months. Differences in nutrient intake and the DII were examined using general linear models with follow-up tests at each time point. We hypothesized that individuals randomized to the vegan diet would have lower DII scores and greater improvements in fiber, carbohydrate, fat, saturated fat, and cholesterol at both 2 and 6 months as compared with the other 4 diets. Participants randomized to the vegan diet had significantly greater changes in most macronutrients at both time points, including fat and saturated fat, as well as cholesterol and, at 2 months, fiber, as compared with most of the other diet groups (Ps < .05). Vegan, vegetarian, and pescovegetarian participants all saw significant improvements in the DII score as compared with semivegetarian participants at 2 months (Ps < .05) with no differences at 6 months. Given the greater impact on macronutrients and the DII during the short term, finding ways to provide support for adoption and maintenance of plant-based dietary approaches, such as vegan and vegetarian diets, should be given consideration. PMID:25532675
Konno, Sensuke
2009-01-01
Maitake D-fraction or PDF is the bioactive extract of maitake mushroom (Grifola frondosa) and its active constituent is the protein-bound polysaccharide (proteoglucan), or more specifically known as β-glucan. PDF has been extensively studied and a number of its medicinal potentials/properties have been unveiled and demonstrated. Those include various physiological benefits ranging from immunomodulatory and antitumor activities to treatment for hypertension, diabetes, hypercholesterolemia, viral infections (hepatitis B and human immunodeficiency virus), and obesity. Particularly, two major biological activities of PDF, immunomodulatory and antitumor activities, have been the main target for scientific and clinical research. To demonstrate and confirm such biological activities, numerous studies have been performed in vitro and in vivo or in clinical settings. These studies showed that PDF was indeed capable of modulating immunologic and hematologic parameters, inhibiting or regressing the cancer cell growth, and even improving quality of life of cancer patients. Synergistic potentiation of PDF with vitamin C demonstrated in vitro is rather interesting and may have clinical implication, because such combination therapy appears to help improve the efficacy of currently ongoing cancer therapies. Recently, intravenous administration of vitamin C has been often used to increase its physiological concentration and this useful procedure may further make this combination therapy feasible. Therefore, PDF may have great potential, either being used solely or combined with other agents, for cancer therapy. Such relevant and detailed studies will be described and discussed herein with a special focus on the combination of PDF and vitamin C as a viable therapeutic option. PMID:20360893
Numerical Solution of Incompressible Navier-Stokes Equations Using a Fractional-Step Approach
NASA Technical Reports Server (NTRS)
Kiris, Cetin; Kwak, Dochan
1999-01-01
A fractional step method for the solution of steady and unsteady incompressible Navier-Stokes equations is outlined. The method is based on a finite volume formulation and uses the pressure in the cell center and the mass fluxes across the faces of each cell as dependent variables. Implicit treatment of convective and viscous terms in the momentum equations enables the numerical stability restrictions to be relaxed. The linearization error in the implicit solution of momentum equations is reduced by using three subiterations in order to achieve second order temporal accuracy for time-accurate calculations. In spatial discretizations of the momentum equations, a high-order (3rd and 5th) flux-difference splitting for the convective terms and a second-order central difference for the viscous terms are used. The resulting algebraic equations are solved with a line-relaxation scheme which allows the use of large time step. A four color ZEBRA scheme is employed after the line-relaxation procedure in the solution of the Poisson equation for pressure. This procedure is applied to a Couette flow problem using a distorted computational grid to show that the method minimizes grid effects. Additional benchmark cases include the unsteady laminar flow over a circular cylinder for Reynolds Numbers of 200, and a 3-D, steady, turbulent wingtip vortex wake propagation study. The solution algorithm does a very good job in resolving the vortex core when 5th-order upwind differencing and a modified production term in the Baldwin-Barth one-equation turbulence model are used with adequate grid resolution.
Costlow, Heather N.; Zhang, Hualin; Das, Indra J.
2014-10-01
The purpose of this study was to explore the treatment planning methods of spatially fractionated megavoltage grid therapy for treating bulky lung tumors using multileaf collimator (MLC). A total of 5 patients with lung cancer who had gross tumor volumes ranging from 277 to 635 cm{sup 3} were retrospectively chosen for this study. The tumors were from 6.5 to 9.6 cm at shortest dimension. Several techniques using either electronic compensation or intensity-modulated radiation therapy (IMRT) were used to create a variety of grid therapy plans on the Eclipse treatment planning system. The dose prescription point was calculated to the volume, and a dose of 20 Gy with 6-MV/15-MV beams was used in each plan. The dose-volume histogram (DVH) curves were obtained to evaluate dosimetric characteristics. In addition, DVH curves from a commercially available cerrobend grid collimator were also used for comparison. The linear-quadratic radiobiological response model was used to assess therapeutic ratios (TRs) and equivalent uniform doses (EUD) for all generated plans. A total of 6 different grid therapy plans were created for each patient. Overall, 4 plans had different electronic compensation techniques: Ecomps-Tubes, Ecomps-Circles, Ecomps-Squares, and Ecomps-Weave; the other 2 plans used IMRT and IMRT-Weave techniques. The DVH curves and TRs demonstrated that these MLC-based grid therapy plans can achieve dosimetric properties very similar to those of the cerrobend grid collimator. However, the MLC-based plans have larger EUDs than those with the cerrobend grid collimator. In addition, the field shaping can be performed for targets of any shape in MLC-based plans. Thus, they can deliver a more conformal dose to the targets and spare normal structures better than the cerrobend grid collimator can. The plans generated by the MLC technique demonstrated the advantage over the standard cerrobend grid collimator on accommodating targets and sparing normal structures. Overall, 6
Papp, D; Unkelbach, J
2014-06-01
Purpose: Non-uniform fractionation, i.e. delivering distinct dose distributions in two subsequent fractions, can potentially improve outcomes by increasing biological dose to the target without increasing dose to healthy tissues. This is possible if both fractions deliver a similar dose to normal tissues (exploit the fractionation effect) but high single fraction doses to subvolumes of the target (hypofractionation). Optimization of such treatment plans can be formulated using biological equivalent dose (BED), but leads to intractable nonconvex optimization problems. We introduce a novel optimization approach to address this challenge. Methods: We first optimize a reference IMPT plan using standard techniques that delivers a homogeneous target dose in both fractions. The method then divides the pencil beams into two sets, which are assigned to either fraction one or fraction two. The total intensity of each pencil beam, and therefore the physical dose, remains unchanged compared to the reference plan. The objectives are to maximize the mean BED in the target and to minimize the mean BED in normal tissues, which is a quadratic function of the pencil beam weights. The optimal reassignment of pencil beams to one of the two fractions is formulated as a binary quadratic optimization problem. A near-optimal solution to this problem can be obtained by convex relaxation and randomized rounding. Results: The method is demonstrated for a large arteriovenous malformation (AVM) case treated in two fractions. The algorithm yields a treatment plan, which delivers a high dose to parts of the AVM in one of the fractions, but similar doses in both fractions to the normal brain tissue adjacent to the AVM. Using the approach, the mean BED in the target was increased by approximately 10% compared to what would have been possible with a uniform reference plan for the same normal tissue mean BED.
NASA Astrophysics Data System (ADS)
Maltese, Antonino; Capodici, Fulvio; La Loggia, Goffredo; Corbari, Chiara; Mancini, Marco
2013-10-01
The assessment of the spatial distribution of soil water content could improve the effectiveness of agro-hydrological models. Although it is possible to retrieve the spatial distribution of the soil water content using thermal inertia, the main limit is its applicability to bare soils only. Recently, a variation of the thermal inertia approach has been setup also on vegetated soils characterized by low fractional cover. In particular, the methodology proposes to attenuate the solar radiation at the top of the canopy to the one reaching the soil trough an extinction factor. In situ data were acquired in June 2011 and July 2012 over two fields of maize and sunflowers; both were at their early growing stages. An airborneplatform provided images in the visible/near infrared and thermal infrared, both in day and night time. Results of the 2011 experiment demonstrated that the vegetation cover correction is required even with low fractional cover; indeed, not applying this correction would results in strong overestimation. The 2012 experiment (REFLEX) further validates the model on an independent dataset, thus, confirming the reliability of the methodology. Furthermore, a spatial resolution analysis highlighted that retrievals at low spatial resolution best compares with in situsoil water content than those obtained at high-resolution. Finally, the availability of a thermal image acquired after irrigating demonstrated the unreliability of the method when soil water content significantly changes between the two thermal acquisitions.
Oetjen, Janina; Lachmund, Delf; Palmer, Andrew; Alexandrov, Theodore; Becker, Michael; Boskamp, Tobias; Maass, Peter
2016-09-01
A standardized workflow for matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI imaging MS) is a prerequisite for the routine use of this promising technology in clinical applications. We present an approach to develop standard operating procedures for MALDI imaging MS sample preparation of formalin-fixed and paraffin-embedded (FFPE) tissue sections based on a novel quantitative measure of dataset quality. To cover many parts of the complex workflow and simultaneously test several parameters, experiments were planned according to a fractional factorial design of experiments (DoE). The effect of ten different experiment parameters was investigated in two distinct DoE sets, each consisting of eight experiments. FFPE rat brain sections were used as standard material because of low biological variance. The mean peak intensity and a recently proposed spatial complexity measure were calculated for a list of 26 predefined peptides obtained by in silico digestion of five different proteins and served as quality criteria. A five-way analysis of variance (ANOVA) was applied on the final scores to retrieve a ranking of experiment parameters with increasing impact on data variance. Graphical abstract MALDI imaging experiments were planned according to fractional factorial design of experiments for the parameters under study. Selected peptide images were evaluated by the chosen quality metric (structure and intensity for a given peak list), and the calculated values were used as an input for the ANOVA. The parameters with the highest impact on the quality were deduced and SOPs recommended. PMID:27485623
Scherr, D
2015-02-01
Catheter ablation is an established treatment option for patients with atrial fibrillation (AF). In paroxysmal AF ablation, pulmonary vein isolation alone is a well-defined procedural endpoint, leading to success rates of up to 80% with multiple procedures over 5 years of follow-up. The success rate in persistent AF ablation is significantly more limited. This is partly due to the rudimentary understanding of the substrate maintaining persistent AF. Three main pathophysiological concepts for this arrhythmia exist: the multiple wavelet hypothesis, the concept of focal triggers, mainly located in the pulmonary veins and the rotor hypothesis. However, the targets and endpoints of persistent AF ablation are ill-defined and there is no consensus on the optimal ablation strategy in these patients. Based on these concepts, several ablation approaches for persistent AF have emerged: pulmonary vein isolation, the stepwise approach (i.e. pulmonary vein isolation, ablation of fractionated electrograms and linear ablation), magnetic resonance imaging (MRI) and rotor-based approaches. Currently, persistent AF ablation is a second-line therapy option to restore and maintain sinus rhythm. Several factors, such as the presence of structural heart disease, duration of persistent AF and dilatation and possibly also the degree of fibrosis of the left atrium should influence the decision to perform persistent AF ablation. PMID:25687615
Bonizzi, Ivan; Buffoni, Joanna Natalia; Feligini, Maria
2009-01-01
The ability to quantify the casein content by an exact and cost-effective approach represents an issue of crucial importance in the dairy industry as the natural variations in milk protein concentration can markedly affect the yield of the cheesemaking processes, thus causing a direct and significant economic impact on the producers. In this work, the separation and quantification of alpha(s1)-, alpha(s2)-, kappa- and beta-casein was carried out by direct RP-HPLC analysis of milk. The identification of each casein was established by electrospray ionization mass spectrometry. The data show that this method is able to effectively separate the bovine casein fractions, it provides simplified analytical conditions (with special regard to mobile phase composition and gradient profile) and faster separation while ensuring adequate precision to achieve reliable quantifications in milk samples from dairy production. PMID:19062022
Yang, Pengyi; Humphrey, Sean J; Fazakerley, Daniel J; Prior, Matthew J; Yang, Guang; James, David E; Yang, Jean Yee-Hwa
2012-05-01
A key step in the analysis of mass spectrometry (MS)-based proteomics data is the inference of proteins from identified peptide sequences. Here we describe Re-Fraction, a novel machine learning algorithm that enhances deterministic protein identification. Re-Fraction utilizes several protein physical properties to assign proteins to expected protein fractions that comprise large-scale MS-based proteomics data. This information is then used to appropriately assign peptides to specific proteins. This approach is sensitive, highly specific, and computationally efficient. We provide algorithms and source code for the current version of Re-Fraction, which accepts output tables from the MaxQuant environment. Nevertheless, the principles behind Re-Fraction can be applied to other protein identification pipelines where data are generated from samples fractionated at the protein level. We demonstrate the utility of this approach through reanalysis of data from a previously published study and generate lists of proteins deterministically identified by Re-Fraction that were previously only identified as members of a protein group. We find that this approach is particularly useful in resolving protein groups composed of splice variants and homologues, which are frequently expressed in a cell- or tissue-specific manner and may have important biological consequences. PMID:22428558
Zhang, Hui; Luo, Li-Ping; Song, Hui-Peng; Hao, Hai-Ping; Zhou, Ping; Qi, Lian-Wen; Li, Ping; Chen, Jun
2014-01-24
Generation of a high-purity fraction library for efficiently screening active compounds from natural products is challenging because of their chemical diversity and complex matrices. In this work, a strategy combining high-resolution peak fractionation (HRPF) with a cell-based assay was proposed for target screening of bioactive constituents from natural products. In this approach, peak fractionation was conducted under chromatographic conditions optimized for high-resolution separation of the natural product extract. The HRPF approach was automatically performed according to the predefinition of certain peaks based on their retention times from a reference chromatographic profile. The corresponding HRPF database was collected with a parallel mass spectrometer to ensure purity and characterize the structures of compounds in the various fractions. Using this approach, a set of 75 peak fractions on the microgram scale was generated from 4mg of the extract of Salvia miltiorrhiza. After screening by an ARE-luciferase reporter gene assay, 20 diterpene quinones were selected and identified, and 16 of these compounds were reported to possess novel Nrf2 activation activity. Compared with conventional fixed-time interval fractionation, the HRPF approach could significantly improve the efficiency of bioactive compound discovery and facilitate the uncovering of minor active components. PMID:24406141
Akers, Jeremy D; Cornett, Rachel A; Savla, Jyoti S; Davy, Kevin P; Davy, Brenda M
2012-05-01
Maintenance of weight loss remains a challenge for most individuals. Thus, practical and effective weight-loss maintenance (WTLM) strategies are needed. A two-group 12-month WTLM intervention trial was conducted from June 2007 to February 2010 to determine the feasibility and effectiveness of a WTLM intervention for older adults using daily self-monitoring of body weight, step count, fruit/vegetable (F/V) intake, and water consumption. Forty weight-reduced individuals (mean weight lost=6.7±0.6 kg; body mass index [calculated as kg/m²] 29.2±1.1), age 63±1 years, who had previously participated in a 12-week randomized controlled weight-loss intervention trial, were instructed to record daily body weight, step count, and F/V intake (WEV [defined as weight, exercise, and F/V]). Experimental group (WEV+) participants were also instructed to consume 16 fl oz of water before each main meal (ie, three times daily), and to record daily water intake. Outcome measures included weight change, diet/physical activity behaviors, theoretical constructs related to health behaviors, and other clinical measures. Statistical analyses included growth curve analyses and repeated measures analysis of variance. Over 12 months, there was a linear decrease in weight (β=-0.32, P<0.001) and a quadratic trend (β=0.02, P<0.01) over time, but no group difference (β=-0.23, P=0.08). Analysis of the 365 days of self-reported body weight for each participant determined that weight loss was greater over the study period in the WEV+ group than in the WEV group, corresponding to weight changes of -0.67 kg and 1.00 kg, respectively, and an 87% greater weight loss (β=-0.01, P<0.01). Overall compliance to daily tracking was 76%±5%. Daily self-monitoring of weight, physical activity, and F/V consumption is a feasible and effective approach for maintaining weight loss for 12 months, and daily self-monitoring of increased water consumption may provide additional WTLM benefits. PMID:22709772
NASA Astrophysics Data System (ADS)
Girotto, M.; Margulis, S. A.; Durand, M. T.; Molotch, N. P.
2010-12-01
Seasonal snowmelt runoff represents one of the major components of water resources in many regions of the world. Lack of knowledge of its spatial and temporal characteristics limits our ability to monitor and predict this vital source of water. Process understanding stands to benefit from an accurate spatial and temporal characterization of the mountain snow water equivalent (SWE) spatial distribution and evolution. A probabilistic approach that takes into account sources of uncertainty from all input data streams (including remote sensing and models and their inputs) while estimating SWE is desired. This work applied a Bayesian reanalysis data assimilation system, similar to an Ensemble Kalman Smoother, capable of merging remotely sensed Snow Covered Area (SCA) data into prediction models, and at the same time account for the limitations of each. Preliminary analysis has identified and characterized the key factors responsible for SWE estimation accuracy, and developed models able to represent their uncertainties within the probabilistic data assimilation approach. The approach was implemented for the characterization of spatially and temporally continuous SWE over a test domain in the Sequoia National Park region of the Sierra Nevada. To assess the performance of the method, SWE spatial estimates are compared with estimates from intense field campaigns, and existing snow-pillow records. SCA estimates from both the standard fractional MODIS product and the advanced MODSCAG are investigated as they have been derived with different retrieval algorithms. The system is designed to use readily available forcing information from the North American Land Data Assimilation System (NLDAS). Prior estimates of SWE are obtained by forcing a land surface model with prior probability distributions of snowfall obtained from the NLDAS precipitation product. A reanalysis step conditions the prior estimates on SCA measurements. A series of preliminary analyses focus on identifying
Park, Jong-Min; Jeong, Migyeong; Kim, Eun-Hee; Han, Young-Min; Kwon, Sung Hun; Hahm, Ki-Baik
2015-01-01
Omega-3 polyunsaturated fatty acids (n-3 PUFAs), commonly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been acknowledged as essential long-chain fatty acids imposing either optimal health promotion or the rescuing from chronic inflammatory diseases such as atherosclerosis, fatty liver, and various inflammatory gastrointestinal diseases. Recent studies dealing with EPA and DHA have sparked highest interests because detailed molecular mechanisms had been documented with the identification of its receptor, G protein coupled receptor, and GPR120. In this review article, we have described clear evidences showing that n-3 PUFAs could reduce various Helicobacter pylori- (H. pylori-) associated gastric diseases and extended to play even cancer preventive outcomes including H. pylori-associated gastric cancer by influencing multiple targets, including proliferation, survival, angiogenesis, inflammation, and metastasis. Since our previous studies strongly concluded that nonantimicrobial dietary approach for reducing inflammation, for instance, application of phytoceuticals, probiotics, natural products including Korean red ginseng, and walnut plentiful of n-3 PUFAs, might be prerequisite step for preventing H. pylori-associated gastric cancer as well as facilitating the rejuvenation of precancerous atrophic gastritis, these beneficial lipids can restore or modify inflammation-associated lipid distortion and correction of altered lipid rafts to send right signaling to maintain healthy stomach even after chronic H. pylori infection. PMID:26339635
Park, Jong-Min; Jeong, Migyeong; Kim, Eun-Hee; Han, Young-Min; Kwon, Sung Hun; Hahm, Ki-Baik
2015-01-01
Omega-3 polyunsaturated fatty acids (n-3 PUFAs), commonly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been acknowledged as essential long-chain fatty acids imposing either optimal health promotion or the rescuing from chronic inflammatory diseases such as atherosclerosis, fatty liver, and various inflammatory gastrointestinal diseases. Recent studies dealing with EPA and DHA have sparked highest interests because detailed molecular mechanisms had been documented with the identification of its receptor, G protein coupled receptor, and GPR120. In this review article, we have described clear evidences showing that n-3 PUFAs could reduce various Helicobacter pylori- (H. pylori-) associated gastric diseases and extended to play even cancer preventive outcomes including H. pylori-associated gastric cancer by influencing multiple targets, including proliferation, survival, angiogenesis, inflammation, and metastasis. Since our previous studies strongly concluded that nonantimicrobial dietary approach for reducing inflammation, for instance, application of phytoceuticals, probiotics, natural products including Korean red ginseng, and walnut plentiful of n-3 PUFAs, might be prerequisite step for preventing H. pylori-associated gastric cancer as well as facilitating the rejuvenation of precancerous atrophic gastritis, these beneficial lipids can restore or modify inflammation-associated lipid distortion and correction of altered lipid rafts to send right signaling to maintain healthy stomach even after chronic H. pylori infection. PMID:26339635
Twerdok, L E
1999-02-01
The Total Petroleum Hydrocarbon Criteria Working Croup (TPHCWG) was formed in 1993 based on the observation that widely different clean-up requirements were being used by states at sites that were contaminated with hydrocarbon materials such as fuels, lubricating oils, and crude oils. These requirements were usually presented as concentration of total petroleum hydrocarbon (TPH), and ranged from 10 to over 10,000 mg TPH/kg soil. Members of this multi-disciplinary group, consisting of representatives from industry, government and academia, jointly recognized that the numerical standard was not based on a scientific assessment of human health risk and established the following goal for the effort: To develop scientifically defensible information for establishing soil cleanup levels that are protective of human health at hydrocarbon contaminated sites. The approach developed by the TPHCWG for TPH hazard assessment consisted of dividing the petroleum hydrocarbon material into multichemical-containing fractions with similar fate and transport characteristics. These fractions were then assigned fate and transport properties (volatilization factor, soil leaching factor, etc.) and toxicity values (RfDs/RfCs) representative of the fraction. The actual site specific hazard assessment and derivation of cleanup levels is accomplished by analyzing sites to determine which fraction(s) is present and applying the appropriate fate, transport and toxicity factors. The method used by this group to determine TPH Faction specific toxicity criteria is a surrogate approach intended to supplement the indicator approach. Indicators are single, carcinogenic hydrocarbon compounds which are evaluated/regulated individually at either the federal or state level. The TPHCWG surrogate approach utilized all appropriate fraction specific toxicity data (single compound and mixture/product), minus the carcinogenic indicator compounds, to derive the fraction specific RfDs and RfCs. This hazard
Technology Transfer Automated Retrieval System (TEKTRAN)
The 13C natural abundance approach for determining soil organic C (SOC) stability and turnover has been used to determine SOC mineralization kinetics. These calculations often assume that 13C fractionation during relic SOC and non-harvested biomass mineralization is insignificant. The objective of t...
NASA Astrophysics Data System (ADS)
Frierdich, Andrew J.; Beard, Brian L.; Reddy, Thiruchelvi R.; Scherer, Michelle M.; Johnson, Clark M.
2014-08-01
The Fe isotope compositions of naturally occurring Fe oxide minerals provide insights into biogeochemical processes that occur in modern and ancient environments. Key to understanding isotopic variations in such minerals is knowledge of the equilibrium Fe isotope fractionation factors between common minerals and aqueous Fe species. Because experimental measurements of isotopic fractionation may reflect a combination of kinetic and equilibrium fractionations during rapid dissolution and precipitation, even in experiments that employ the three-isotope method, assessment of the attainment of equilibrium is often difficult. Here, we re-examine Fe isotope exchange, via a 57Fe tracer, and natural mass-dependent fractionation, through changes in initial 56Fe/54Fe ratios, between aqueous Fe(II) (Fe(II)aq) and goethite. This approach uses the three-isotope method, but is distinct in its evaluation of kinetic isotope fractionation and the attainment of equilibrium by: (i) employing a multi-direction approach to equilibrium at 22 °C via reaction of three Fe(II)aq solutions that had different initial 56Fe/54Fe ratios, (ii) conducting isotopic exchange experiments at elevated temperature (50 °C), and (iii) modifying the rate of isotopic exchange through a combination of trace-element substitutions and particle coarsening to evaluate corresponding temporal changes in fractionation trajectories that may reflect changing instantaneous fractionation factors. We find that rapid isotopic exchange produces kinetic isotope effects between Fe(II)aq and goethite, which shifts the 56Fe/54Fe ratios of Fe(II)aq early in reactions toward that of goethite, indicating that the instantaneous Fe(II)aq-goethite fractionation factor under kinetic conditions is small. Importantly, however, this kinetic fractionation is “erased” with continued reaction, and this is evident by the congruence for multiple-exchange trajectories of distinct initial Fe(II)aq solutions toward the same final value
Augustsson, Anna; Berger, Tobias
2014-07-01
It is often assumed that water consumption is the major route of exposure for fluoride and analysis of water fluoride content is the most common approach for ensuring that the daily intake is not too high. In the present study, the risk of excess intake was characterized for children in households with private wells in Kalmar County, Sweden, where the natural geology shows local enrichments in fluorine. By comparing water concentrations with the WHO drinking water guideline (1.5 mg/L), it was found that 24% of the ca. 4800 sampled wells had a concentration above this limit, hence providing a figure for the number of children in the households concerned assessed to be at risk using this straightforward approach. The risk of an excess intake could, alternatively, also be characterized based on a tolerable daily intake (in this case the US EPA RfD of 0.06 mg/kg-day). The exposure to be evaluated was calculated using a probabilistic approach, where the variability in all exposure factors was considered, again for the same study population. The proportion of children assessed to be at risk after exposure from drinking water now increased to 48%, and when the probabilistic model was adjusted to also include other possible exposure pathways; beverages and food, ingestion of toothpaste, oral soil intake and dust inhalation, the number increased to 77%. Firstly, these results show how the risk characterization is affected by the basis of comparison. In this example, both of the reference values used are widely acknowledged. Secondly, it illustrates how much of the total exposure may be overlooked when only focusing on one exposure pathway, and thirdly, it shows the importance of considering the variability in all relevant pathways. PMID:24747328
NASA Astrophysics Data System (ADS)
Ahangari, Zahra
2016-02-01
This paper explores the impact of indium mole fraction on the electrical characteristic of In x Ga1- x As double-gate Schottky MOSFET (SBFET) in nanoscale regime. A 20-band sp 3 d 5 s * tight-binding formalism is applied to compute the bandstructure of ultra-thin body structure as a function of indium mole fraction. The injection velocity of carriers is increased as the indium mole fraction approaches to x = 1. Quantum confinement results in an increment of the effective Schottky barrier height especially for the increased values of indium mole fraction. The ultra-scaled In x Ga1- x As SBFET suffers from a low conduction band DOS in the Γ valley that results in serious degradation of the gate capacitance. The electrical characteristic of this device is considered by solving self-consistent 2D Schrődinger-Poisson equations based on non-equilibrium Green's function formalism. For channel thicknesses where the effect of quantum confinement on the gate capacitance is not dominant, shrinking the channel thickness besides increasing the indium mole fraction improves the electrical characteristic of the device. However, for the ultra-scaled structure, the indium mole fraction enhancement degrades the device performance due to the enhanced value of Schottky barrier height and low DOS.
Fractional vector calculus and fractional Maxwell's equations
Tarasov, Vasily E.
2008-11-15
The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.
NASA Astrophysics Data System (ADS)
Wollscheid, D.; Lion, A.
2014-05-01
The dynamic properties of rubber-like materials are characterised by a significant dependence on the predeformation and the frequency. The focus of this paper is to represent the frequency and predeformation dependent dynamic behaviour of a carbon-black filled SBR rubber with 40 phr amount of filler using the concept of fractional derivatives. Thus, we introduce a constitutive approach of finite fractional viscoelasticity which is suitable to approximate the dynamic material properties with respect to the storage and the loss modulus. The constitutive approach is based on a proposal of [18] which was modified by a deformation dependent relaxation function in a previous work [46] to represent the dependence of the dynamic modulus on the predeformation and the frequency. The constitutive approach in [46] is based on the classical theory of finite viscoelasticity and formulated in the frequency domain. In this work, the approach of [46] will be extended by the concept of fractional derivatives and compared to the classical one. Thus, the classical and the extended fractional constitutive models are firstly introduced and the complex modulus tensors of both models are derived. It should be mentioned that both constitutive approaches are firstly formulated in the time domain. This formulation is necessary to satisfy the thermodynamical consistency. In order to conduct vibration analyses of elastomer structures with high computational efficiency, the equations are then transferred to the frequency domain. To this end, the constitutive model is geometrically linearised in the neighbourhood of a large and temporally constant predeformation. The incremental strain tensor varies harmonically and its amplitude has to be small. Furthermore, parameter identification of both approaches is done on the basis of quasi-static and dynamic investigations of the carbon-black filled SBR rubber. The numerical results of the parameter identification of the classical and the fractional
Wu, J.-N.; Huang, C.-H.; Cheng, S.-C.; Hsieh, W.-F.
2010-02-15
Spontaneous emission (SE) from a two-level atom in an anisotropic photonic crystal (PC) is investigated by the fractional calculus. Physical phenomena of the SE are studied analytically by solving the fractional kinetic equations of the SE. There is a dynamical discrepancy between the SE of anisotropic and isotropic PCs. We find that, contrary to the SE phenomenon of the isotropic PC, the SE near the band edge of an anisotropic PC shows no photon-atom bound state. It is consistent with the experimental results of Barth, Schuster, Gruber, and Cichos [Phys. Rev. Lett. 96, 243902 (2006)] that the anisotropic property of the system enhances the SE. We also study effects of dispersion curvatures on the changes of the photonic density of states and the appearance of the diffusion fields in the SE.
Energy and macronutrient intakes of professional football (soccer) players.
Maughan, R J
1997-01-01
OBJECTIVE: To examine the dietary habits of professional soccer players at two Scottish Premier League clubs during the competitive season. METHODS: A study of the dietary intake of 51 professional soccer players with two different clubs was carried out by the seven day weighed intake method. RESULTS: Physical characteristics of the two groups of players were similar, with only small differences in age and body mass but no difference in height and body fat. Mean (SD) daily energy intake for club A was 11.0 (2.6) MJ, and for club B 12.8 (2.2) MJ. The higher energy intake at club B was largely accounted for by a higher (P < 0.005) fat intake (118 v 93 g d-1): there was no difference in the absolute amounts of protein, carbohydrate, or alcohol consumed. When expressed as a fraction of total energy intake, mean protein intake was higher (P < 0.05) and fat intake lower (P < 0.01) at club A. CONCLUSIONS: The mean energy intake of these players was not high compared with athletes in endurance sports. Fractional contribution of the macronutrients to total energy intake was broadly similar to that of the general population. PMID:9132211
Graham, Margaret C; Oliver, Ian W; Mackenzie, Angus B; Ellam, Robert M; Farmer, John G
2008-10-01
Methods for the fractionation of aquatic colloids require careful application to ensure efficient, accurate and reproducible separations. This paper describes the novel combination of mild colloidal fractionation and characterisation methods, namely centrifugal ultrafiltration, gel electrophoresis and gel filtration along with spectroscopic (UV-visible) and elemental (Inductively Coupled Plasma-Optical Emission Spectroscopy, Inductively Coupled Plasma-Mass Spectrometry) analysis, an approach which produced highly consistent results, providing improved confidence in these methods. Application to the study of the colloidal and dissolved components of soil porewaters from one soil at a depleted uranium (DU)-contaminated site revealed uranium (U) associations with both large (100 kDa-0.2 microm) and small (3-30 kDa) humic colloids. For a nearby soil with lower organic matter content, however, association with large (100 kDa-0.2 microm) iron (Fe)-aluminium (Al) colloids in addition to an association with small (3-30 kDa) humic colloids was observed. The integrated colloid fractionation approach presented herein can now be applied with confidence to investigate U and indeed other trace metal migration in soil and aquatic systems. PMID:18635249
NASA Technical Reports Server (NTRS)
Wignarajah, Kanapathipillai; Pisharody, Suresh; Fisher, John W.
2003-01-01
The elemental composition of food consumed by astronauts is well defined. The major elements carbon, hydrogen, oxygen, nitrogen and sulfur are taken up in large amounts and these are often associated with the organic fraction (carbohydrates, proteins, fats etc) of human tissue. On the other hand, a number of the elements are located in the extracellular fluids and can be accounted for in the liquid and solid waste fraction of humans. These elements fall into three major categories - cationic macroelements (e.g. Ca, K, Na, Mg and Si), anionic macroelements (e.g. P, S and Cl and 17 essential microelements, (e.g. Fe, Mn, Cr, Co, Cu, Zn, Se and Sr). When provided in the recommended concentrations to an adult healthy human, these elements should not normally accumulate in humans and will eventually be excreted in the different human wastes. Knowledge of the partitioning of these elements between the different human waste fractions is important in understanding (a) developing waste separation technologies, (b) decision-making on how these elements can be recovered for reuse in space habitats, and (c) to developing the processors for waste management. Though considerable literature exists on these elements, there is a lack of understanding and often conflicting data. Two major reasons for these problems include the lack of controlled experimental protocols and the inherently large variations between human subjects (Parker and Gallagher, 1988). We have used the existing knowledge of human nutrition and waste from the available literature and NASA documentation to build towards a consensus to typify and chemically characterize the various human wastes. It is our belief, that this could be a building block towards integrating a human life support and waste processing in a closed system.
NASA Technical Reports Server (NTRS)
Snyder, Gregory A.; Taylor, Lawrence A.
1992-01-01
It is generally considered that lunar mare basalts were generated by the melting of a cumulate mantle formed in an early Moon-wide magma ocean or magmasphere. However, the nature and chemistry of this cumulate mantle and the logistics of its origin have remained elusive. Extensive studies of terrestrial layered mafic intrusions over the past sixty years have emphasized the imperfection of fractional crystallization and attendant crystal-crystal and crystal-liquid separation in a convecting magma chamber. These separations were similarly inefficient during evolution of the lunar magmasphere, allowing for the trapping of interstitial melt and entrainment of a small proportion of less-dense plagioclase into the more-dense mafic cumulate mush. Indeed, petrography of lunar highlands samples demonstrates this well for anorthosites (with 1-10 percent olivine). Therefore, we propose a 'realistic' model for the evolution of the lunar mantle, which takes these observations into consideration, by the imperfect fractional crystallization of an early lunar magma ocean.
NASA Astrophysics Data System (ADS)
Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich; Qi, Naiming
2013-11-01
A physics-based fractional-order Maxwell resistive capacitor (FOMRC) model is proposed to characterize nonlinear hysteresis and creep behaviors of a piezoelectric actuator (PEA). The Maxwell resistive capacitor (MRC) model is interpreted physically in the electric domain for PEAs. Based on this interpretation, the MRC model is modified to directly describe the relationship between the input voltage and the output displacement of a PEA. Then a procedure is developed to identify the parameters of the MRC model. This procedure is capable of being carried out using the measured input and output of a PEA only. A fractional-order dynamics is integrated into the MRC model to describe the effect of creep, as well as the detachment of hysteresis loops caused by creep. Moreover, the inverse FOMRC model is constructed to compensate for hysteresis and creep in an open-loop positioning application of PEAs. Simulation and experiments are carried out to validate the proposed model. The PEA compensated by the inverse FOMRC model shows an excellent linear behavior.
Lorber, Matthew; Schecter, Arnold; Paepke, Olaf; Shropshire, William; Christensen, Krista; Birnbaum, Linda
2015-04-01
Bisphenol A (BPA) is a high-volume, synthetic compound found in epoxy resins and plastics used in food packaging. Food is believed to be a major source of BPA intake. In this study, we measured the concentration of BPA in convenience samplings of foodstuffs purchased in Dallas, Texas. Sampling entailed collection of 204 samples of fresh, frozen, and canned foods in two rounds in 2010. BPA was positive in 73% of the canned food samples, while it was found in only 7% of non-canned foods at low concentrations. The results of this food sampling program were used to calculate adult dietary intakes of BPA. A pathway approach combined food intakes, a "canned fraction" parameter which described what portion of total intake of that food came from canned products, and measured food concentrations. Dietary intakes were calculated as 12.6 ng/kg-day, of which 12.4 ng/kg-day was from canned foods. Canned vegetable intakes alone were 11.9 ng/kg-day. This dietary intake was compared to total intakes of BPA estimated from urine measurements of the National Health and Nutrition Examination Survey (NHANES). Total adult central tendency intakes ranged from 30 to 70 ng/kg-day for NHANES cycles between 2005 and 2010. Three possibilities were explored to explain the difference between these two approaches for intake estimation. Not all foods which may have been canned, particularly canned beverages such as soft drinks, were sampled in our food sampling program. Second, non-food pathways of exposure may be important for adults, including thermal paper exposures, and dust and air exposures. Finally, our canned food concentrations may not be adequately representative of canned foods in the United States; they were found to be generally lower compared to canned food concentrations measured in six other worldwide food surveys including three in North America. Our finding that canned food concentrations greatly exceeded non-canned concentrations was consistent with other studies, and
Sartorius, B; Sartorius, K; Aldous, C; Madiba, T E; Stefan, C; Noakes, T
2016-01-01
Introduction Linkages between carbohydrates, obesity and cancer continue to demonstrate conflicting results. Evidence suggests inconclusive direct linkages between carbohydrates and specific cancers. Conversely, obesity has been strongly linked to a wide range of cancers. The purpose of the study is to explore linkages between carbohydrate intake and cancer types using a two-step approach. First the study will evaluate the linkages between carbohydrate intake and obesity, potentially stratified by metabolic syndrome status. Second, the estimated attributable fraction of obesity ascribed to carbohydrate intake will be multiplied against obesity attributable fractions for cancer types to give estimated overall attributable fraction for carbohydrate versus cancer type. Methods and analysis We will perform a comprehensive search to identify all possible published and unpublished studies that have assessed risk factors for obesity including dietary carbohydrate intake. Scientific databases, namely PubMed MEDLINE, EMBASE, EBSCOhost and ISI Web of Science will be searched. Following study selection, paper/data acquisition, and data extraction and synthesis, we will appraise the quality of studies and risk of bias, as well as assess heterogeneity. Meta-weighted attributable fractions of obesity due to carbohydrate intake will be estimated after adjusting for other potential confounding factors (eg, physical inactivity, other dietary intake). Furthermore, previously published systematic reviews assessing the cancer-specific risk associated with obesity will also be drawn. These estimates will be linked with the attributability of carbohydrate intake in part 1 to estimate the cancer-specific burden that can be attributed to dietary carbohydrates. This systematic review protocol has been developed according to the ‘Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) 2015’. Ethics and dissemination The current study will be based on
Gu, Sen; Qian, Yiguang; Jiao, Yang; Li, Qingman; Pinay, Gilles; Gruau, Gerard
2016-10-15
Accurate identification of phosphorus (P) forms is crucially important for understanding the geochemical cycle of P; however, until now the role of ferrous iron P (Fe(II)-P) buried in sediments has been completely ignored in nearly all sequential extraction procedures developed. Using sediment cores sampled from Donghu Lake in Wuhan, China, this study explored a modified version of widely used sequential P extraction method (SEDEX; Ruttenberg, 1992) in which Fe(II)-P was identified as an independent fraction. Based on the high selectivity of the extractant (0.2% 2,2'-bipyridine+0.1 M KCl) and the dissolution equilibrium of P, procedures for extracting Fe(II)-P were optimized using a 1:100 solid:liquid ratio and extraction at 50 ± 1 °C for 24 h. The sedimentary P extracted was divided into five fractions: loosely-bound P, Fe(II)-P, CDB-P, Ca-P and O-P. Fe(II)-P was the predominant fraction in fresh sediments in Donghu Lake, accounting for 15.7-49.9% of TP, with a mean of 31.6%. The mean values of Ca-P, O-P, CDB-P and loosely-bound P were 28.4%, 22.7%, 17.1% and 4.3%, respectively. Combined with component analysis of extracts and recovery experiments of standard reference minerals (vivianite, Fe3(PO4)2·8H2O) in natural sediments, extraction of Fe(II)-P with 0.2% 2,2-bipridine and 0.1 M KCl was robust, with a good recovery rate (88.7-100.6%) and little of the Ca-P dissolved. It is possible to use this innovative SEDEX not only to distinguish the contribution of different P matrices in fresh sediments, but also to investigate the transformation of sedimentary P under different redox conditions. Therefore, greater focus on Fe(II)-P is necessary, because it is a major sink for the geochemical process of sedimentary P. PMID:27486948
NASA Astrophysics Data System (ADS)
Ge, J.; Everett, M. E.; Weiss, C. J.
2012-12-01
A 2.5D finite difference (FD) frequency-domain modeling algorithm based on the theory of fractional diffusion of electromagnetic (EM) fields generated by a loop source lying above a fractured geological medium is addressed in this paper. The presence of fractures in the subsurface, usually containing highly conductive pore fluids, gives rise to spatially hierarchical flow paths of induced EM eddy currents. The diffusion of EM eddy currents in such formations is anomalous, generalizing the classical Gaussian process described by the conventional Maxwell equations. Based on the continuous time random walk (CTRW) theory, the diffusion of EM eddy currents in a rough medium is governed by the fractional Maxwell equations. Here, we model the EM response of a 2D subsurface containing fractured zones, with a 3D loop source, which results the so-called 2.5D model geometry. The governing equation in the frequency domain is converted using Fourier transform into k domain along the strike direction (along which the model conductivity doesn't vary). The resulting equation system is solved by the multifrontal massively parallel solver (MUMPS). The data obtained is then converted back to spatial domain and the time domain. We find excellent agreement between the FD and analytic solutions for a rough halfspace model. Then FD solutions are calculated for a 2D fault zone model with variable conductivity and roughness. We compare the results with responses from several classical models and explore the relationship between the roughness and the spatial density of the fracture distribution.
NASA Astrophysics Data System (ADS)
Lods, Gerard; Gouze, Philippe
2004-11-01
The identification of the hydraulic characteristics and transport properties of fractured reservoirs requires the development of specific models that account for (i) the medium heterogeneity, e.g. the presence of major conductive fractures that delimit capacitive matrix blocks, with weakly open, dead end or isolated fractures , and (ii) for the geometrical arrangement of the major conductive fractures network, which dominates the flow at the scale of the well tests. Well Tests in Fractured Media (WTFM) software takes into account these two main features by combining radial flow generalized to fractional dimension, with the theory of double-porosity, including diffusivity in the second porosity, transient inter-porosity flow and inter-porosity skin effect, and with leakance. The implementation of this nD model, with n fractional, extends usefully the domain of application of the usual 1D/2D/3D double-porosity/leakance models for a large range of connection levels of fracture networks. Although the fractures geometry and properties are not considered one by one, or by directional families, they are taken into account by averaged properties and by the impact that the whole network has on the hydrodynamic behaviour. The accuracy of the coupled transient behaviours analysis is augmented by taking into account wellbore storage and skin effects. All together, the use of these different options allows matching a wide range of pumping test curves, characteristics of distinctive behaviours, with a limited number of parameters. Distinctive well test experiments, in both sedimentary and crystalline rocks, are presented for enlightening how the pertinent use of the model options improves predictions.
NASA Astrophysics Data System (ADS)
Leite, Argentina; Paula Rocha, Ana; Eduarda Silva, Maria
2013-06-01
Heart Rate Variability (HRV) series exhibit long memory and time-varying conditional variance. This work considers the Fractionally Integrated AutoRegressive Moving Average (ARFIMA) models with Generalized AutoRegressive Conditional Heteroscedastic (GARCH) errors. ARFIMA-GARCH models may be used to capture and remove long memory and estimate the conditional volatility in 24 h HRV recordings. The ARFIMA-GARCH approach is applied to fifteen long term HRV series available at Physionet, leading to the discrimination among normal individuals, heart failure patients, and patients with atrial fibrillation.
Wang, Qian; Molenaar, Peter; Harsh, Saurabh; Freeman, Kenneth; Xie, Jinyu; Gold, Carol; Rovine, Mike; Ulbrecht, Jan
2014-03-24
An essential component of any artificial pancreas is on the prediction of blood glucose levels as a function of exogenous and endogenous perturbations such as insulin dose, meal intake, and physical activity and emotional tone under natural living conditions. In this article, we present a new data-driven state-space dynamic model with time-varying coefficients that are used to explicitly quantify the time-varying patient-specific effects of insulin dose and meal intake on blood glucose fluctuations. Using the 3-variate time series of glucose level, insulin dose, and meal intake of an individual type 1 diabetic subject, we apply an extended Kalman filter (EKF) to estimate time-varying coefficients of the patient-specific state-space model. We evaluate our empirical modeling using (1) the FDA-approved UVa/Padova simulator with 30 virtual patients and (2) clinical data of 5 type 1 diabetic patients under natural living conditions. Compared to a forgetting-factor-based recursive ARX model of the same order, the EKF model predictions have higher fit, and significantly better temporal gain and J index and thus are superior in early detection of upward and downward trends in glucose. The EKF based state-space model developed in this article is particularly suitable for model-based state-feedback control designs since the Kalman filter estimates the state variable of the glucose dynamics based on the measured glucose time series. In addition, since the model parameters are estimated in real time, this model is also suitable for adaptive control. PMID:24876585
Mehl, Florence; Marti, Guillaume; Boccard, Julien; Debrus, Benjamin; Merle, Philippe; Delort, Estelle; Baroux, Lucie; Raymo, Vilfredo; Velazco, Maria Inés; Sommer, Horst; Wolfender, Jean-Luc; Rudaz, Serge
2014-01-15
Due to the importance of citrus lemon oil for the industry, fast and reliable analytical methods that allow the authentication and/or classification of such oil, using the origin of production or extraction process, are necessary. To evaluate the potential of volatile and non-volatile fractions for classification purposes, volatile compounds of cold-pressed lemon oils were analyzed, using GC-FID/MS and FT-MIR, while the non-volatile residues were studied, using FT-MIR, (1)H-NMR and UHPLC-TOF-MS. 64 Lemon oil samples from Argentina, Spain and Italy were considered. Unsupervised and supervised multivariate analyses were sequentially performed on various data blocks obtained by the above techniques. Successful data treatments led to statistically significant models that discriminated and classified cold-pressed lemon oils according to their geographic origin, as well as their production processes. Studying the loadings allowed highlighting of important classes of discriminant variables that corresponded to putative or identified chemical functions and compounds. PMID:24054247
Bjorgan, Asgeir; Randeberg, Lise Lyngsnes
2015-01-01
Processing line-by-line and in real-time can be convenient for some applications of line-scanning hyperspectral imaging technology. Some types of processing, like inverse modeling and spectral analysis, can be sensitive to noise. The MNF (minimum noise fraction) transform provides suitable denoising performance, but requires full image availability for the estimation of image and noise statistics. In this work, a modified algorithm is proposed. Incrementally-updated statistics enables the algorithm to denoise the image line-by-line. The denoising performance has been compared to conventional MNF and found to be equal. With a satisfying denoising performance and real-time implementation, the developed algorithm can denoise line-scanned hyperspectral images in real-time. The elimination of waiting time before denoised data are available is an important step towards real-time visualization of processed hyperspectral data. The source code can be found at http://www.github.com/ntnu-bioopt/mnf. This includes an implementation of conventional MNF denoising. PMID:25654717
NASA Astrophysics Data System (ADS)
Zhong, Fuli; Li, Hui; Zhong, Shouming; Zhong, Qishui; Yin, Chun
2015-07-01
A state of charge (SOC) estimation approach based on an adaptive sliding mode observer (SMO) and a fractional order equivalent circuit model (FOECM) for lithium-ion batteries is proposed in this paper. In order to design the adaptive sliding mode observer (SMO) for the SOC estimation, the state equations based on a FOECM of battery are derived. A new self-adjusting strategy for the observer gains is presented to adjust the observer in the estimating process, which helps to reduce chattering and convergence time. Furthermore, a continuous and smooth function called hyperbolic tangent function is applied to balance the chattering affection and the disturbance. At last, a battery simulation model is established to test the SOC estimation performance of the designed SMOs, and the results show the proposed approach is feasible and effective.
Technology Transfer Automated Retrieval System (TEKTRAN)
The Dietary Reference Intakes (DRI) are recommendations intended to provide a framework for nutrient intake evaluation, as well as meal planning on the basis of nutrient adequacy. They are nutrient, not food based recommendations, created with chronic disease risk reduction as the primary goal, as ...
de Oliveira, Daniela R.; Zamberlam, Claudia R.; Rêgo, Gizelda M.; Cavalheiro, Alberto; Cerutti, Janete M.; Cerutti, Suzete M.
2016-01-01
The effects of flavonoids have been correlated with their ability to modulate the glutamatergic, serotoninergic, and GABAergic neurotransmission; the major targets of these substances are N-methyl-D-aspartic acid receptor (NMDARs), serotonin type1A receptor (5-HT1ARs), and the gamma-aminobutyric acid type A receptors (GABAARs). Several studies showed that these receptors are involved in the acquisition and extinction of fear memory. This study assessed the effects of treatment prior to conditioning with a flavonoid-rich fraction from the stem bark of Erythrina falcata (FfB) on the acquisition and extinction of the conditioned suppression following pharmacological manipulations and on gene expression in the dorsal hippocampus (DH). Adult male Wistar rats were treated before conditioned fear with FfB, vehicle, an agonist or antagonist of the 5-HT1AR, GABAARs or the GluN2B-NMDAR or one of these antagonists before FfB treatment. The effects of these treatments on fear memory retrieval, extinction training and extinction retrieval were evaluated at 48, 72, and 98 h after conditioning, respectively. We found that activation of GABAARs and inactivation of GluN2B-NMDARs play important roles in the acquisition of lick response suppression. FfB reversed the effect of blocking GluN2B-NMDARs on the conditioned fear and induced the spontaneous recovery. Blocking the 5-HT1AR and the GluN2B-NMDAR before FfB treatment seemed to be associated with weakening of the spontaneous recovery. Expression of analysis of DH samples via qPCR showed that FfB treatment resulted in the overexpression of Htr1a, Grin2a, Gabra5, and Erk2 after the retention test and of Htr1a and Erk2 after the extinction retention test. Moreover, blocking the 5-HT1ARs and the GluN2B-NMDARs before FfB treatment resulted in reduced Htr1a and Grin2b expression after the retention test, but played a distinct role in Grin2a and Erk2 expression, according session evaluated. We show for the first time that the
NASA Astrophysics Data System (ADS)
Graff, Jennifer Whitney
Currently the world energy usage has nearly tripled since 1950 and is projected to grow at a rate of 1.5% per year and predicted to at least double from the beginning of the millennium to 2050. The United States alone is currently consuming more energy than it can produce (≈ 97 Quadrillion BTU's consumed in 2011).(1) Presently, fossil fuels make up over 85% of our energy landscape, including both the stationary grid (like coal and nuclear power plants) and the mobile grid (automobiles using gas and oil). This presents a major demand for developing methods of saving, storing, and renewing energy. Answers to these existing energy demands must come from a variety of renewable sources including: solar, wind, biomass, geothermal and others. But currently, most renewable sources are only a small part of the big energy picture. One approach to this exponentially growing problem, lies within high efficiency (15%-20%) thermoelectric (TE) materials which address small, yet very important and specific, parts of a bigger problem. Specifically, Co4Sb12-based skutterudites, an increasingly favorable thermoelectric material for mid to high temperature applications (currently used in General Motors TE Generator devices). These materials have the ability to be 'tuned' or controlled thermally and electrically through doping and filling mechanisms, as you will see in this dissertation. However, one of the major drawbacks of TE materials is the difficulty in optimizing both electrical and thermal properties simultaneously. Typically, different control parameters are used in order to enhance the electrical and thermal properties individually. It is very rare to observe optimization of both in a TE material via one control parameter. However, the work presented herein successfully augments all TE properties, with one control variable, by using an approach that can be applied to all doped skutterudites and clathrate materials. Skutterudites are novel materials in that they are a binary
Stanislavsky, A A
2004-11-01
We consider a fractional oscillator which is a generalization of the conventional linear oscillator in the framework of fractional calculus. It is interpreted as an ensemble average of ordinary harmonic oscillators governed by a stochastic time arrow. The intrinsic absorption of the fractional oscillator results from the full contribution of the harmonic oscillator ensemble: these oscillators differ a little from each other in frequency so that each response is compensated by an antiphase response of another harmonic oscillator. This allows one to draw a parallel in the dispersion analysis for media described by a fractional oscillator and an ensemble of ordinary harmonic oscillators with damping. The features of this analysis are discussed. PMID:15600586
Kamoun-Essghaier, Sayda; Guizani, Ikram; Strub, Jean Marc; Van Dorsselaer, Alain; Mabrouk, Kamel; Ouelhazi, Lazhar; Dellagi, Koussay
2005-01-01
The aim of the present study was to identify and characterize proteins of a 30- to 36-kDa fraction of Leishmania infantum promastigote membranes previously shown to be an immunodominant antigen(s) in Mediterranean visceral leishmaniasis (MVL) and a consistent and reliable serological marker of this disease. By the first approach, Coomassie-stained protein bands (32- and 33-kDa fractions) that specifically reacted by immunoblotting with sera from MVL patients were excised from the gel and submitted to enzymatic digestion to generate peptides. Four peptides were sequenced, three of which were shown to be definitely associated with MVL-reactive antigens and ascribed to a mitochondrial integral ADP-ATP carrier protein from L. major, a putative NADH cytochrome b5 reductase, and a putative mitochondrial carrier protein, respectively. The second approach combined two-dimensional gel electrophoresis of membrane antigens and mass spectrometry (liquid chromatography-mass spectrometry/mass spectrometry) by using a quadrupole time-of-flight analysis. Six immunoreactive spots that resolved within a molecular mass range of 30 to 36 kDa and a pH range of 6.7 to 7.4 corresponded to four Leishmania products. The sequences derived from two spots were ascribed to a beta subunit-like guanine nucleotide binding protein, known as the activated protein kinase C receptor homolog antigen LACK, and to a probable member of the aldehyde reductase family. One spot was identified as a probable ubiquinol-cytochrome c reductase (EC 1.10.2.2) Rieske iron-sulfur protein precursor. The remaining three spots were identified as truncated forms of elongation factor 1α. These antigens correspond to conserved proteins ubiquitously expressed in eukaryotic cells and represent potential candidates for the design of a reliable tool for the diagnosis of this disease. PMID:15699427
Nutrient Intake in Heart Failure Patients
Grossniklaus, Daurice A.; O’Brien, Marian C.; Clark, Patricia C.; Dunbar, Sandra B.
2009-01-01
Background and Research Objective Approximately 50% of heart failure (HF) patients are thought to be malnourished, and macronutrient and micronutrient deficiencies may potentially aggravate HF symptoms. Thus, concerns have been raised about the overall nutrient composition of diets in HF populations. The purpose of this study was to examine the macronutrient and micronutrient intake by caloric adequacy among community-dwelling adults with HF. Participants and Methods A secondary analysis of baseline data of participants in an HF lifestyle intervention study was conducted. Participants (n = 45) were predominantly male (55.6%), white, and non-Hispanic (64.4%); had a mean age of 61 years (SD, 11 years) and mean body mass index of 31.2 kg/m2 (SD, 7.3 kg/m2); were of New York Heart Association functional classes II and III (77.8%); and had a mean ejection fraction of 31.9% (SD,13.2%); and 69% had a college or higher level of education. The Block Food Habits Questionnaire was used to assess the intake of macronutrients and micronutrients. Analysis included descriptive statistics and Mann-Whitney U tests. Results and Conclusions Individuals reporting inadequate daily caloric intake reported a lower intake of macronutrients and micronutrients as well as other differences in dietary patterns compared with individuals reporting adequate daily caloric intake. More than half of the individuals reporting adequate caloric intake did not meet the recommended dietary allowance for magnesium and vitamin E. Interventions aimed at increasing overall intake and nutrient density are suggested. Further research is needed to better understand the relationship between dietary factors and outcomes in HF. PMID:18596500
Marassi, V; Roda, B; Zattoni, A; Tanase, M; Reschiglian, P
2014-10-30
Monoclonal antibodies (mAbs) are promising reagents both for the manufacture of drug substances and for their employment as a drug themselves, but to be approved for utilization, according to FDA recommendations and WHO guidelines, they have to undergo verifications regarding their purity, stability and percentage of aggregates. Moreover, stability tests of lots have to be performed in order to verify molecular size distribution over time and lot-to-lot consistency. Recent works in literature have highlighted the need for suitable, sensitive and reliable complementary analytical techniques for the characterization of mAbs and quantification of aggregates. Size-exclusion chromatography (SEC) is the reference technique in the biopharmaceutical industry for its robustness, high performance and simple use; however it presents some limitations especially toward the separation and detection of aggregates with high molecular weight. On the other hand, flow field-flow fractionation (F4) in its miniaturized version (hollow fiber flow field-flow fractionation, HF5) shows comparable performances with interesting additional advantages: a broad size range, gentle separation mechanism with low dilution factor and higher sensitivity. To propose HF5 as a complementary technique for evaluating aggregates' content in mAbs samples, a comparative study of both SEC and HF5 performances has been made. In this work, SEC and HF5 were coupled with UV and multi-angle light scattering detection and employed first in separating standard samples of proteins mixture used as a sample model. Then, a screening of mobile phases and an evaluation of separation performances was performed on a therapeutic mAbs formulation, demonstrating the complementarities between SEC and HF5 and their possible use as a separative platform approach for the characterization and quality control of protein drugs. PMID:25468501
Kochunov, Peter; Jahanshad, Neda; Sprooten, Emma; Nichols, Thomas E.; Mandl, René C.; Almasy, Laura; Booth, Tom; Brouwer, Rachel M.; Curran, Joanne E.; de Zubicaray, Greig I.; Dimitrova, Rali; Duggirala, Ravi; Fox, Peter T.; Hong, L. Elliot; Landman, Bennett A.; Lemaitre, Hervé; Lopez, Lorna; Martin, Nicholas G.; McMahon, Katie L.; Mitchell, Braxton D.; Olvera, Rene L.; Peterson, Charles P.; Starr, John M.; Sussmann, Jessika E.; Toga, Arthur W.; Wardlaw, Joanna M.; Wright, Margaret J.; Wright, Susan N.; Bastin, Mark E.; McIntosh, Andrew M.; Boomsma, Dorret I.; Kahn, René S.; den Braber, Anouk; de Geus, Eco JC; Deary, Ian J.; Hulshoff Pol, Hilleke E.; Williamson, Douglas E.; Blangero, John; van ’t Ent, Dennis; Thompson, Paul M.; Glahn, David C.
2014-01-01
Combining datasets across independent studies can boost statistical power by increasing the numbers of observations and can achieve more accurate estimates of effect sizes. This is especially important for genetic studies where a large number of observations are required to obtain sufficient power to detect and replicate genetic effects. There is a need to develop and evaluate methods for joint-analytical analyses of rich datasets collected in imaging genetics studies. The ENIGMA-DTI consortium is developing and evaluating approaches for obtaining pooled estimates of heritability through meta-and mega-genetic analytical approaches, to estimate the general additive genetic contributions to the intersubject variance in fractional anisotropy (FA) measured from diffusion tensor imaging (DTI). We used the ENIGMA-DTI data harmonization protocol for uniform processing of DTI data from multiple sites. We evaluated this protocol in five family-based cohorts providing data from a total of 2248 children and adults (ages: 9–85) collected with various imaging protocols. We used the imaging genetics analysis tool, SOLAR-Eclipse, to combine twin and family data from Dutch, Australian and Mexican-American cohorts into one large “mega-family”. We showed that heritability estimates may vary from one cohort to another. We used two meta-analytical (the sample-size and standard-error weighted) approaches and a mega-genetic analysis to calculate heritability estimates across-population. We performed leave-one-out analysis of the joint estimates of heritability, removing a different cohort each time to understand the estimate variability. Overall, meta- and mega-genetic analyses of heritability produced robust estimates of heritability. PMID:24657781
Kochunov, Peter; Jahanshad, Neda; Sprooten, Emma; Nichols, Thomas E; Mandl, René C; Almasy, Laura; Booth, Tom; Brouwer, Rachel M; Curran, Joanne E; de Zubicaray, Greig I; Dimitrova, Rali; Duggirala, Ravi; Fox, Peter T; Hong, L Elliot; Landman, Bennett A; Lemaitre, Hervé; Lopez, Lorna M; Martin, Nicholas G; McMahon, Katie L; Mitchell, Braxton D; Olvera, Rene L; Peterson, Charles P; Starr, John M; Sussmann, Jessika E; Toga, Arthur W; Wardlaw, Joanna M; Wright, Margaret J; Wright, Susan N; Bastin, Mark E; McIntosh, Andrew M; Boomsma, Dorret I; Kahn, René S; den Braber, Anouk; de Geus, Eco J C; Deary, Ian J; Hulshoff Pol, Hilleke E; Williamson, Douglas E; Blangero, John; van 't Ent, Dennis; Thompson, Paul M; Glahn, David C
2014-07-15
Combining datasets across independent studies can boost statistical power by increasing the numbers of observations and can achieve more accurate estimates of effect sizes. This is especially important for genetic studies where a large number of observations are required to obtain sufficient power to detect and replicate genetic effects. There is a need to develop and evaluate methods for joint-analytical analyses of rich datasets collected in imaging genetics studies. The ENIGMA-DTI consortium is developing and evaluating approaches for obtaining pooled estimates of heritability through meta-and mega-genetic analytical approaches, to estimate the general additive genetic contributions to the intersubject variance in fractional anisotropy (FA) measured from diffusion tensor imaging (DTI). We used the ENIGMA-DTI data harmonization protocol for uniform processing of DTI data from multiple sites. We evaluated this protocol in five family-based cohorts providing data from a total of 2248 children and adults (ages: 9-85) collected with various imaging protocols. We used the imaging genetics analysis tool, SOLAR-Eclipse, to combine twin and family data from Dutch, Australian and Mexican-American cohorts into one large "mega-family". We showed that heritability estimates may vary from one cohort to another. We used two meta-analytical (the sample-size and standard-error weighted) approaches and a mega-genetic analysis to calculate heritability estimates across-population. We performed leave-one-out analysis of the joint estimates of heritability, removing a different cohort each time to understand the estimate variability. Overall, meta- and mega-genetic analyses of heritability produced robust estimates of heritability. PMID:24657781
Peleteiro, Bárbara; Barros, Susana; Castro, Clara; Ferro, Ana; Morais, Samantha; Lunet, Nuno
2016-08-01
Assessing the impact that patterns of Na intake may have on gastric cancer will provide a more comprehensive estimation of Na reduction as a primary prevention approach. We aimed to estimate the proportion of gastric cancer cases that are attributable to Na intake above the recommendation by the WHO (≤2 g/d) throughout the world in 2010, as well as expected values for 2030. Population attributable fractions (PAF) were computed for 187 countries, using Na intakes in 1990 and 2010 and estimates of the association between Na intake and gastric cancer, assuming a time lag of 20 years. Median PAF ranged from 10·1% in low to 22·5 % in very high Human Development Index (HDI) countries in men (P<0·001) and from 7·2 to 16·6 %, respectively, among women (P<0·001). An increase in median PAF until 2030 is expected in most settings, except for countries classified as low HDI, in both sexes. High Na intakes account for a large proportion of gastric cancer cases, and proportions are expected to increase in almost all of the countries. Intensified efforts to diminish Na intake in virtually all populations are needed to further reduce gastric cancer burden. PMID:27358114
Fractional calculus in bioengineering.
Magin, Richard L
2004-01-01
Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub
Garcia-Perez, Isabel; Posma, Joram M; Chambers, Edward S; Nicholson, Jeremy K; C Mathers, John; Beckmann, Manfred; Draper, John; Holmes, Elaine; Frost, Gary
2016-03-23
Lack of accurate dietary assessment in free-living populations requires discovery of new biomarkers reflecting food intake qualitatively and quantitatively to objectively evaluate effects of diet on health. We provide a proof-of-principle for an analytical pipeline to identify quantitative dietary biomarkers. Tartaric acid was identified by nuclear magnetic resonance spectroscopy as a dose-responsive urinary biomarker of grape intake and subsequently quantified in volunteers following a series of 4-day dietary interventions incorporating 0 g/day, 50 g/day, 100 g/day, and 150 g/day of grapes in standardized diets from a randomized controlled clinical trial. Most accurate quantitative predictions of grape intake were obtained in 24 h urine samples which have the strongest linear relationship between grape intake and tartaric acid excretion (r(2) = 0.90). This new methodological pipeline for estimating nutritional intake based on coupling dietary intake information and quantified nutritional biomarkers was developed and validated in a controlled dietary intervention study, showing that this approach can improve the accuracy of estimating nutritional intakes. PMID:26909845
Fraction Reduction through Continued Fractions
ERIC Educational Resources Information Center
Carley, Holly
2011-01-01
This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.
Chekli, L; Roy, M; Tijing, L D; Donner, E; Lombi, E; Shon, H K
2015-08-15
Titanium dioxide nanoparticles (TiO2 NPs) are currently one of the most prolifically used nanomaterials, resulting in an increasing likelihood of release to the environment. This is of concern as the potential toxicity of TiO2 NPs has been investigated in several recent studies. Research into their fate and behaviour once entering the environment is urgently needed to support risk assessment and policy development. In this study, we used a multi-method approach combining light scattering and field-flow fractionation techniques to assess both the aggregation behaviour and aggregate structure of TiO2 NPs in different river waters. Results showed that both the aggregate size and surface-adsorbed dissolved organic matter (DOM) were strongly related to the initial DOM concentration of the tested waters (i.e. R(2) > 0.90) suggesting that aggregation of TiO2 NPs is controlled by the presence and concentration of DOM. The conformation of the formed aggregates was also found to be strongly related to the surface-adsorbed DOM (i.e. R(2) > 0.95) with increasing surface-adsorbed DOM leading to more compact structures. Finally, the concentration of TiO2 NPs remaining in the supernatant after sedimentation of the larger aggregates was found to decrease proportionally with both increasing IS and decreasing DOM concentration, resulting in more than 95% sedimentation in the highest IS sample. PMID:26067894
The report gives results of an evaluation of a porous dike intake. A small-scale test facility was constructed and continuously operated for 2 years under field conditions. Two stone dikes of gabion construction were tested: one consisted of 7.5 cm stones; and the other, 20 cm st...
Sobrino Crespo, Carmen; Perianes Cachero, Aránzazu; Puebla Jiménez, Lilian; Barrios, Vicente; Arilla Ferreiro, Eduardo
2014-01-01
The mechanisms for controlling food intake involve mainly an interplay between gut, brain, and adipose tissue (AT), among the major organs. Parasympathetic, sympathetic, and other systems are required for communication between the brain satiety center, gut, and AT. These neuronal circuits include a variety of peptides and hormones, being ghrelin the only orexigenic molecule known, whereas the plethora of other factors are inhibitors of appetite, suggesting its physiological relevance in the regulation of food intake and energy homeostasis. Nutrients generated by food digestion have been proposed to activate G-protein-coupled receptors on the luminal side of enteroendocrine cells, e.g., the L-cells. This stimulates the release of gut hormones into the circulation such as glucagon-like peptide-1 (GLP-1), oxyntomodulin, pancreatic polypeptides, peptide tyrosine tyrosine, and cholecystokinin, which inhibit appetite. Ghrelin is a peptide secreted from the stomach and, in contrast to other gut hormones, plasma levels decrease after a meal and potently stimulate food intake. Other circulating factors such as insulin and leptin relay information regarding long-term energy stores. Both hormones circulate at proportional levels to body fat content, enter the CNS proportionally to their plasma levels, and reduce food intake. Circulating hormones can influence the activity of the arcuate nucleus (ARC) neurons of the hypothalamus, after passing across the median eminence. Circulating factors such as gut hormones may also influence the nucleus of the tractus solitarius (NTS) through the adjacent circumventricular organ. On the other hand, gastrointestinal vagal afferents converge in the NTS of the brainstem. Neural projections from the NTS, in turn, carry signals to the hypothalamus. The ARC acts as an integrative center, with two major subpopulations of neurons influencing appetite, one of them coexpressing neuropeptide Y and agouti-related protein (AgRP) that increases food
Sobrino Crespo, Carmen; Perianes Cachero, Aránzazu; Puebla Jiménez, Lilian; Barrios, Vicente; Arilla Ferreiro, Eduardo
2014-01-01
The mechanisms for controlling food intake involve mainly an interplay between gut, brain, and adipose tissue (AT), among the major organs. Parasympathetic, sympathetic, and other systems are required for communication between the brain satiety center, gut, and AT. These neuronal circuits include a variety of peptides and hormones, being ghrelin the only orexigenic molecule known, whereas the plethora of other factors are inhibitors of appetite, suggesting its physiological relevance in the regulation of food intake and energy homeostasis. Nutrients generated by food digestion have been proposed to activate G-protein-coupled receptors on the luminal side of enteroendocrine cells, e.g., the L-cells. This stimulates the release of gut hormones into the circulation such as glucagon-like peptide-1 (GLP-1), oxyntomodulin, pancreatic polypeptides, peptide tyrosine tyrosine, and cholecystokinin, which inhibit appetite. Ghrelin is a peptide secreted from the stomach and, in contrast to other gut hormones, plasma levels decrease after a meal and potently stimulate food intake. Other circulating factors such as insulin and leptin relay information regarding long-term energy stores. Both hormones circulate at proportional levels to body fat content, enter the CNS proportionally to their plasma levels, and reduce food intake. Circulating hormones can influence the activity of the arcuate nucleus (ARC) neurons of the hypothalamus, after passing across the median eminence. Circulating factors such as gut hormones may also influence the nucleus of the tractus solitarius (NTS) through the adjacent circumventricular organ. On the other hand, gastrointestinal vagal afferents converge in the NTS of the brainstem. Neural projections from the NTS, in turn, carry signals to the hypothalamus. The ARC acts as an integrative center, with two major subpopulations of neurons influencing appetite, one of them coexpressing neuropeptide Y and agouti-related protein (AgRP) that increases food
Huber, Stefan; Klein, Elise; Willmes, Klaus; Nuerk, Hans-Christoph; Moeller, Korbinian
2014-01-01
Decimal fractions comply with the base-10 notational system of natural Arabic numbers. Nevertheless, recent research suggested that decimal fractions may be represented differently than natural numbers because two number processing effects (i.e., semantic interference and compatibility effects) differed in their size between decimal fractions and natural numbers. In the present study, we examined whether these differences indeed indicate that decimal fractions are represented differently from natural numbers. Therefore, we provided an alternative explanation for the semantic congruity effect, namely a string length congruity effect. Moreover, we suggest that the smaller compatibility effect for decimal fractions compared to natural numbers was driven by differences in processing strategy (sequential vs. parallel). To evaluate this claim, we manipulated the tenth and hundredth digits in a magnitude comparison task with participants’ eye movements recorded, while the unit digits remained identical. In addition, we evaluated whether our empirical findings could be simulated by an extended version of our computational model originally developed to simulate magnitude comparisons of two-digit natural numbers. In the eye-tracking study, we found evidence that participants processed decimal fractions more sequentially than natural numbers because of the identical leading digit. Importantly, our model was able to account for the smaller compatibility effect found for decimal fractions. Moreover, string length congruity was an alternative account for the prolonged reaction times for incongruent decimal pairs. Consequently, we suggest that representations of natural numbers and decimal fractions do not differ. PMID:24744717
Toward lattice fractional vector calculus
NASA Astrophysics Data System (ADS)
Tarasov, Vasily E.
2014-09-01
An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.
Dietary intakes of pesticides based on community duplicate diet samples
The calculation of dietary intake of selected pesticides was accomplished using food samples collected from individual representatives of a defined demographic community using a community duplicate diet approach. A community of nine participants was identified in Apopka, FL from...
Food characteristics, long-term habituation and energy intake. Laboratory and field studies
Technology Transfer Automated Retrieval System (TEKTRAN)
Food variety is related to increased energy intake, and one approach to reduce food intake is to reduce food variety. However characteristics of foods that constitute variety are not known. The effects of varying food characteristics to reduce food variety on laboratory and usual dinner intake was ...
Callister, Stephen J.; Dominguez, Migual; Nicora, Carrie D.; Zeng, Xiaohua; Tavano, Christine; Kaplan, Samuel; Donohue, Timothy; Smith, Richard D.; Lipton, Mary S.
2006-08-04
Abstract The high-throughput accurate mass and time tag (AMT) proteomic approach was utilized to characterize the proteomes for cytoplasm, cytoplasmic membrane, periplasm, and outer membrane fractions from aerobic and photosynthetic cultures of the gram-nagtive bacterium Rhodobacter sphaeroides 2.4.1. In addition, we analyzed the proteins within purified chromatophore fractions that house the photosynthetic apparatus from photosynthetically grown cells. In total, 8300 peptides were identified with high confidence from at least one sub-cellular fraction from either cell culture. These peptides were derived from 1514 genes or 35% percent of proteins predicted to be encoded by the genome. A significant number of these proteins were detected within a single sub-cellular fraction and their localization was compared to in-silico predictions. However, the majority of proteins were observed in multiple sub-cellular fractions, and the most likely sub-cellular localization for these proteins was investigated using a Z-score analysis of peptide abundance along with clustering techniques. Good (81%) agreement was observed between the experimental results and in-silico predictions. The AMT tag approach provides localization evidence for those proteins that have no predicted localization information, those annotated as putative proteins, and/or for those proteins annotated as hypothetical and conserved hypothetical.
Describing dry matter intake and growth patterns in beef steers during the finishing period
Technology Transfer Automated Retrieval System (TEKTRAN)
Feed intake is central to animal production systems, as it impacts efficiency and represents a substantial fraction of the total costs. The objectives of this study were to: (i) assess feed intake, weight gain and feed efficiency in Angus crossbred steers during finishing on a total mixed diet; and...
Biomarker of whole grain wheat intake associated lower BMI in older adults
Technology Transfer Automated Retrieval System (TEKTRAN)
Alkylresorcinols (AR) are phenolic lipids in the bran fraction of some whole grains (wheat, rye and barley). Plasma AR reflect recent intake of these whole grains. We examined the cross-sectional associations between plasma AR (measured by LCMS/ MS), whole wheat intake, and body mass index (BMI) in ...
Landwehr, J.M.; Meier-Augenstein, W.; Kemp, H.F.
2011-01-01
Hair is a keratinous tissue that incorporates hydrogen from material that an animal consumes but it is metabolically inert following synthesis. The stable hydrogen isotope composition of hair has been used in ecological studies to track migrations of mammals as well as for forensic and archaeological purposes to determine the provenance of human remains or the recent geographic life trajectory of living people. Measurement of the total hydrogen isotopic composition of a hair sample yields a composite value comprised of both metabolically informative, non-exchangeable hydrogen and exchangeable hydrogen, with the latter reflecting ambient or sample preparation conditions. Neither of these attributes is directly measurable, and the non-exchangeable hydrogen composition is obtained by estimation using a commonly applied mathematical expression incorporating sample measurements obtained from two distinct equilibration procedures. This commonly used approach treats the fraction of exchangeable hydrogen as a mixing ratio, with a minimal procedural fractionation factor assumed to be close or equal to 1. Instead, we propose to use full molar ratios to derive an expression for the non-exchangeable hydrogen composition explicitly as a function of both the procedural fractionation factor α and the molar hydrogen exchange fraction fE. We apply these derivations in a longitudinal study of a hair sample and demonstrate that the molar hydrogen exchange fraction fE should, like the procedural fractionation factor α, be treated as a process-dependent parameter, i.e. a reaction-specific constant. This is a counter-intuitive notion given that maximum theoretical values for the molar hydrogen exchange fraction fE can be calculated that are arguably protein-type specific and, as such, fE could be regarded as a compound-specific constant. We also make some additional suggestions for future approaches to determine the non-exchangeable hydrogen composition of hair and the use of
Ouldamer, Lobna; Nadal-Desbarats, Lydie; Chevalier, Stephan; Body, Gilles; Goupille, Caroline; Bougnoux, Philippe
2016-03-01
The fatty acids composition of adipose tissue may provide information on the nutritional part of the risk or evolution of breast cancer. To determine whether (1)H NMR of adipose tissue provides information on the nature of the diet consumed, a dietary intervention with increasing percentage of polyunsaturated n-3 docosahexaenoic acid (DHA 22:6n-3, provided as DHASCO oil) was applied to a rat model of N-nitroso-N-methylurea-induced mammary tumors. Spectra of the lipid extracts were obtained from adipose tissues in five groups of Sprague-Dawley rats fed with a diet containing 7% peanut/rapeseed enriched with 8% (w/w) of an oil without (palm oil) or with low (1%), moderate (3%), or high (8%) DHASCO content. A control group received a basal diet with 15% peanut/rapeseed representative of the "Western" diet. After 5 months of those five controlled diets, adipose tissue was collected for analysis of the lipid extract using both (1)H NMR analysis on an 11.7 T spectrometer and gas chromatography considered as gold standard. (1)H NMR analysis showed a dose-dependent increase in DHA in the lipid extract of adipose tissues and a commensurate decrease in n-6 polyunsaturated fatty acids in the three DHA groups, which allowed one to follow n-6/n-3 ratio changes. The highest n-6/n-3 ratio was observed in the control Western diet group compared to the other diet groups. The integrated spectral regions showed separation between groups, thereby documenting a specific NMR lipid profile corresponding to each dietary intervention. Those diet-dependent NMR lipid profiles were consistent with that obtained with gas chromatography analyses of the same samples. This study is a proof of concept highlighting the potential use of the (1)H NMR approach to evaluate dietary intervention in biopsies of adipose tissues. PMID:26754345
The organic fraction of municipal solid waste provides abundant opportunities for industrial ecology-based symbiotic use. Energy production, economics, and environmental aspects are analyzed for four alternatives based on different technologies: incineration with energy recovery...
soil organic matter fractionation
NASA Astrophysics Data System (ADS)
Osat, Maryam; Heidari, Ahmad
2010-05-01
Carbon is essential for plant growth, due to its effects on other soil properties like aggregation. Knowledge of dynamics of organic matter in different locations in the soil matrix can provide valuable information which affects carbon sequestration and soil the other soil properties. Extraction of soil organic matter (SOM) fractions has been a long standing approach to elucidating the roles of soil organic matter in soil processes. Several kind fractionation methods are used and all provide information on soil organic matter function. Physical fractionation capture the effects on SOM dynamics of the spatial arrangement of primary and secondary organomineral particles in soil while chemical fractionation can not consider the spatial arrangement but their organic fractions are suitable for advanced chemical characterization. Three method of physical separation of soil have been used, sieving, sedimentation and densitometry. The distribution of organic matter within physical fractions of the soil can be assessed by sieving. Sieving separates soil particles based strictly on size. The study area is located on north central Iran, between 35° 41'- 36° 01' N and 50° 42'- 51° 14' E. Mean annual precipitation about 243.8 mm and mean annual air temperature is about 14.95 °C. The soil moisture and temperature regime vary between aridic-thermic in lower altitudes to xeric-mesic in upper altitudes. More than 36 surface soil samples (0-20 cm) were collected according to land-use map units. After preliminary analyzing of samples 10 samples were selected for further analyses in five size fractions and three different time intervals in September, January and April 2008. Fractionation carried out by dry sieving in five classes, 1-2 mm, 0.5-1 mm, 270 μm-0.5mm, 53-270 μm and <53 μm. Organic matter and C/N ratio were determined for all fractions at different time intervals. Chemical fractionation of organic matter also carried out according to Tan (2003), also Mineralogical
Young, Andrew
2005-01-01
Over 100 publications, principally from five groups, describe an effect of amylin and amylin analogs in inhibition of food intake in animals and humans. The major groups contributing to this area are those of the following: Chance and Balasubramaniam (Balasubramaniam et al., 1991a,b; Chance et al., 1991a,b, 1992a,b, 1993). Morley, Flood, and Edwards (Edwards and Morley, 1992; Flood and Morley, 1992; Macintosh et al., 2000; Morley and Flood, 1991, 1994; Morley et al., 1992, 1993, 1994, 1995, 1996, 1997). Lutz, Geary, and others (Barth et al., 2003; Del Prete et al., 2002; Lutz et al., 1994, 1995a,b, 1996a,b, 1997a,b, 1998a,b,c, 2000a,b, 2001a,b,c, 2003; Mollet et al., 2001, 2003a,b, 2004; Riediger et al., 2002, 2004; Rushing et al., 2000a,b, 2001, 2002). Workers at Amylin Pharmaceuticals Inc., or their collaborators (Bhavsar et al., 1995, 1996, 1997a, 1998; Birkemo et al., 1995; Chapman et al., 2004a,b; Edwards et al., 1998; Feinle et al., 2002; Mack et al., 2003; Riediger et al., 1999; Roth et al., 2004; Watkins et al., 1996; Weyer et al., 2004; Young, 1997; Young and Bhavsar, 1996). Arnelo, Reidelberger, and others (Arnelo et al., 1996a,b, 1997a,b, 1998, 2000; Fruin et al., 1997; Granqvist et al., 1997; Reidelberger et al., 2001, 2002, 2004). The magnitude of amylin inhibition of food intake, and its potency for this effect when delivered peripherally, suggests a physiological role in satiogenesis. Increases in food intake following disruption of amylin signal-signaling (e.g., with amylin receptor blockade, or with amylin gene knock-out mice) further support a role of endogenous amylin to tonically restrict nutrient intake. In addition, synergies with other endogenous satiety agents may be present, and convey greater physiological importance than is conveyed by single signals. The anorectic effect of amylin is consistent with a classic amylin pharmacology. The anorectic effect of peripheral amylin appears principally due to a direct action at the area postrema
NASA Astrophysics Data System (ADS)
Hashemi, M. S.; Baleanu, D.
2016-07-01
We propose a simple and accurate numerical scheme for solving the time fractional telegraph (TFT) equation within Caputo type fractional derivative. A fictitious coordinate ϑ is imposed onto the problem in order to transform the dependent variable u (x , t) into a new variable with an extra dimension. In the new space with the added fictitious dimension, a combination of method of line and group preserving scheme (GPS) is proposed to find the approximate solutions. This method preserves the geometric structure of the problem. Power and accuracy of this method has been illustrated through some examples of TFT equation.
The medical management of unintentional radionuclide intakes.
Breitenstein, B D
2003-01-01
As a general medical problem, radionuclide intakes that may cause significant health effects are uncommon events. In preparing to manage a radionuclide accident, planning is the key. The medical aspects of such an accident are only one part of the management, and a professional team approach is required. Specific priorities and sequencing are necessary in medically managing a radionuclide intake. As soon as is reasonably practical, promptly remove the victim(s) from further radionuclide, radiation field, or chemical exposure. Life and limb-saving medical aid takes precedence over ionising radiation concerns in nearly all cases. Next are the prevention and/or minimisation of internal intake of radionuclides and evaluation and control of external radionuclide contamination, followed by institution of treatment to minimise the retained radionuclide. Communication with the accident victim, and his or her family, and public affairs/media issues are important. Finally, follow-up treatment for internal intakes that may cause delayed health effects is given. PMID:14527016
Shock Induced Separating Flows in Scramjet Intakes
NASA Astrophysics Data System (ADS)
Yao, Yufeng; Rincon, Daniel; Zheng, Yao
Shock induced separating flows in a scramjet intake has been studied by using a computational fluid dynamics approach. A configuration of scramjet intake geometry consisting of two exterior compression ramps, followed by a subsequent inlet and interior isolator/diffuser assembly, is chosen. The flow conditions are incoming Mach 7 with free-stream static temperature of 46.3K and wall temperature of 300K, respectively. Consequently, oblique shock wave will be formed and its interaction with viscous boundary layers will lead to flow separation that is responsible for the loss of mass flow, total pressure and several other effects. Simulations confirmed that it is necessary to include the cowl wedge in order to predict wall pressure distributions along the lower surface of the intake walls. It is also shown that mesh topology has some influences on prediction results with structured mesh gives better predictions than that of hybrid mesh. A total of eight turbulence models have been applied and results have shown reasonably good agreement with the experimental measurements and other numerical predictions, with small differences occur in localized regions particularly after shock reflection inside the intake channel. Not surprisingly, shock induced flow separation occurs and it correlates well with higher wall pressure and heating downstream. This phenomenon will have significant impact on deteriorating boundary layer property and consequently the engine performance.
Dietary intake of artificial sweeteners by the Belgian population.
Huvaere, Kevin; Vandevijvere, Stefanie; Hasni, Moez; Vinkx, Christine; Van Loco, Joris
2012-01-01
This study investigated whether the Belgian population older than 15 years is at risk of exceeding ADI levels for acesulfame-K, saccharin, cyclamate, aspartame and sucralose through an assessment of usual dietary intake of artificial sweeteners and specific consumption of table-top sweeteners. A conservative Tier 2 approach, for which an extensive label survey was performed, showed that mean usual intake was significantly lower than the respective ADIs for all sweeteners. Even consumers with high intakes were not exposed to excessive levels, as relative intakes at the 95th percentile (p95) were 31% for acesulfame-K, 13% for aspartame, 30% for cyclamate, 17% for saccharin, and 16% for sucralose of the respective ADIs. Assessment of intake using a Tier 3 approach was preceded by optimisation and validation of an analytical method based on liquid chromatography with mass spectrometric detection. Concentrations of sweeteners in various food matrices and table-top sweeteners were determined and mean positive concentration values were included in the Tier 3 approach, leading to relative intakes at p95 of 17% for acesulfame-K, 5% for aspartame, 25% for cyclamate, 11% for saccharin, and 7% for sucralose of the corresponding ADIs. The contribution of table-top sweeteners to the total usual intake (<1% of ADI) was negligible. A comparison of observed intake for the total population with intake for diabetics (acesulfame-K: 3.55 versus 3.75; aspartame: 6.77 versus 6.53; cyclamate: 1.97 versus 2.06; saccharine: 1.14 versus 0.97; sucralose: 3.08 versus 3.03, expressed as mg kg(-1) bodyweight day(-1) at p95) showed that the latter group was not exposed to higher levels. It was concluded that the Belgian population is not at risk of exceeding the established ADIs for sweeteners. PMID:22088137
Selkowitz, David J.; Forster, Richard; Caldwell, Megan K.
2014-01-01
Remote sensing of snow-covered area (SCA) can be binary (indicating the presence/absence of snow cover at each pixel) or fractional (indicating the fraction of each pixel covered by snow). Fractional SCA mapping provides more information than binary SCA, but is more difficult to implement and may not be feasible with all types of remote sensing data. The utility of fractional SCA mapping relative to binary SCA mapping varies with the intended application as well as by spatial resolution, temporal resolution and period of interest, and climate. We quantified the frequency of occurrence of partially snow-covered (mixed) pixels at spatial resolutions between 1 m and 500 m over five dates at two study areas in the western U.S., using 0.5 m binary SCA maps derived from high spatial resolution imagery aggregated to fractional SCA at coarser spatial resolutions. In addition, we used in situ monitoring to estimate the frequency of partially snow-covered conditions for the period September 2013–August 2014 at 10 60-m grid cell footprints at two study areas with continental snow climates. Results from the image analysis indicate that at 40 m, slightly above the nominal spatial resolution of Landsat, mixed pixels accounted for 25%–93% of total pixels, while at 500 m, the nominal spatial resolution of MODIS bands used for snow cover mapping, mixed pixels accounted for 67%–100% of total pixels. Mixed pixels occurred more commonly at the continental snow climate site than at the maritime snow climate site. The in situ data indicate that some snow cover was present between 186 and 303 days, and partial snow cover conditions occurred on 10%–98% of days with snow cover. Four sites remained partially snow-free throughout most of the winter and spring, while six sites were entirely snow covered throughout most or all of the winter and spring. Within 60 m grid cells, the late spring/summer transition from snow-covered to snow-free conditions lasted 17–56 days and averaged 37
Neitzel, D.A.; McKenzie, D.H.
1981-12-01
To minimize adverse impact on aquatic ecosystems resulting from the operation of water intake structures, design engineers must have relevant information on the behavior, physiology and ecology of local fish and shellfish. Identification of stimulus/response relationships and the environmental factors that influence them is the first step in incorporating biological information in the design, location or modification of water intake structures. A procedure is presented in this document for providing biological input to engineers who are designing, locating or modifying a water intake structure. The authors discuss sources of stimuli at water intakes, historical approaches in assessing potential/actual impact and review biological information needed for intake design.
Lavanya, Melcureraj; Meenakshisundaram, Arunachalam; Renganathan, Sahadevan; Chinnasamy, Senthil; Lewis, David Milton; Nallasivam, Jaganathan; Bhaskar, Sailendra
2016-03-01
Biocrude was produced from Tetraselmis sp. - a marine alga and Arthrospira platensis - a fresh water alga using hydrothermal liquefaction (HTL) process. Considering the constraints in cultivating algae for replacing 100% petrocrude, this study evaluated the option of blending and co-processing algal biocrude with petrocrude. Biocrudes obtained from algal strains cultivated in fresh water and sea water were blended with petrocrude at 10% concentration and the characteristics were studied using FT-IR and CNS SIMDIST. True Boiling Point (TBP) distillation was carried out to assess yields and properties of distillates of blended biocrudes. Biocrudes obtained from both algae were light crudes and the blended crudes recorded distillate yields of 76-77 wt%. The yield of light naphtha fraction of biocrude blends was 29-30%; whereas the yield of diesel fraction was about 18%. This study proposes blending and co-processing of algal biocrude with petrocrude to produce drop-in biofuels. PMID:26735877
NASA Astrophysics Data System (ADS)
Zenkour, Ashraf M.; Abouelregal, Ahmed E.
2014-02-01
This paper is concerned with the determination of the thermoelastic displacement, stress, conductive temperature, and thermodynamic temperature in an infinite isotropic elastic body with a spherical cavity. A general solution to the problem based on the two-temperature generalized thermoelasticity theory (2TT) is introduced. The theory of thermal stresses based on the heat conduction equation with Caputo's time-fractional derivative of order α is used. Some special cases of coupled thermoelasticity and generalized thermoelasticity with one relaxation time are obtained. The general solution is provided by using Laplace's transform and state-space techniques. It is applied to a specific problem when the boundary of the cavity is subjected to thermomechanical loading (thermal shock). Some numerical analyses are carried out using Fourier's series expansion techniques. The computed results for thermoelastic stresses, conductive temperature, and thermodynamic temperature are shown graphically and the effects of two-temperature and fractional-order parameters are discussed.
NASA Astrophysics Data System (ADS)
Nagy, Á.
1990-10-01
The density-functional theory for ensembles of fractional occupation formulated by Gross, Oliveira, and Kohn [Phys. Rev. A 37, 2821 (1988)] has been applied. The excitation energies of several atoms have been determined using a parameter-free exchange potential of Gáspár [Acta Phys. Hung. 35, 213 (1974)]. The calculated excitation energies are in good agreement with the experimental values.
Patrier, P.; Papapanagiotou, P.; Beaufort, D.; Traineau, H.; Bril, H.
1992-01-01
We have investigated by X-ray diffraction the very fine grained secondary minerals (< 0.2 {micro}m) developed in geothermal systems, in relation with their present thermal and permeability state. Because the smallest particles are the most reactive part of a rock, they are the youngest mineral phases of the geothermal fields. This study has been performed on two active geothermal fields: Milos field, Greece (130 < T < 320 C) and Chipilapa field, Salvador (90 < T < 215 C). In the Milos field, the mineralogical composition of the < 0.2 {micro}m clay fraction observed in the reservoir strongly differs from the overlying altered metamorphic schists in the presence of abundant quantities of saponite and talc/saponite interstratified minerals at unusually high temperature. These phases are considered to be kinetically control-led ''metastable'' minerals which rapidly evolve towards actinolite and talc for present temperatures higher than 300 C. Their occurrence is a good indicator of discharge in highly permeable zones. In the geothermal field of Chipilapa, the mineralogical composition of the < 0.2 {micro}m clay fractions fairly agrees with the temperatures presently measured in the wells, whereas several discrepancies may be pointed out from the compositions of coarser clay fractions (< 5 {micro}m) which contain minerals inherited from higher temperature stages. Permeable zones may be evidenced from an increase of expandable components in the interstratified minerals and a decrease of the coherent domain of the unexpandable clay particles (chlorite).
Vitamin K Intake and Atherosclerosis
Technology Transfer Automated Retrieval System (TEKTRAN)
It has been hypothesized that insufficient intake of vitamin K may increase soft tissue calcification due to impaired gamma-carboxylation of the vitamin K-dependent protein, matrix gamma-carboxyglutamic acid (MGP). The evidence to support this putative role of vitamin K intake in atherosclerosis is ...
Power plant intake entrainment analysis
Edinger, J.E.; Kolluru, V.S.
2000-04-01
Power plant condenser cooling water intake entrainment of fish eggs and larvae is becoming an issue in evaluating environmental impacts around the plants. Methods are required to evaluate intake entrainment on different types of water bodies. Presented in this paper is a derivation of the basic relationships for evaluating entrainment from the standing crop of fish eggs and larvae for different regions of a water body, and evaluating the rate of entrainment from the standing crop. These relationships are coupled with a 3D hydrodynamic and transport model that provides the currents and flows required to complete the entrainment evaluation. Case examples are presented for a simple river system, and for the more complex Delaware River Estuary with multiple intakes. Example evaluations are made for individual intakes, and for the cumulative impacts of multiple intakes.
Perrichon, Prescilla; Le Menach, Karyn; Akcha, Farida; Cachot, Jérôme; Budzinski, Hélène; Bustamante, Paco
2016-10-15
Petroleum compounds from chronic discharges and oil spills represent an important source of environmental pollution. To better understand the deleterious effects of these compounds, the toxicity of water-accommodated fractions (WAF) from two different oils (brut Arabian Light and Erika heavy fuel oils) were used in this study. Zebrafish embryos (Danio rerio) were exposed during 96h at three WAF concentrations (1, 10 and 100% for Arabian Light and 10, 50 and 100% for Erika) in order to cover a wide range of polycyclic aromatic hydrocarbon (PAH) concentrations, representative of the levels found after environmental oil spills. Several endpoints were recorded at different levels of biological organization, including lethal endpoints, morphological abnormalities, photomotor behavioral responses, cardiac activity, DNA damage and exposure level measurements (EROD activity, cyp1a and PAH metabolites). Neither morphological nor behavioral or physiological alterations were observed after exposure to Arabian Light fractions. In contrast, the Erika fractions led a high degree of toxicity in early life stages of zebrafish. Despite of defense mechanisms induced by oil, acute toxic effects have been recorded including mortality, delayed hatching, high rates of developmental abnormalities, disrupted locomotor activity and cardiac failures at the highest PAH concentrations (∑TPAHs=257,029±47,231ng·L(-1)). Such differences in toxicity are likely related to the oil composition. The use of developing zebrafish is a good tool to identify wide range of detrimental effects and elucidate their underlying foundations. Our work highlights once more, the cardiotoxic action (and potentially neurotoxic) of petroleum-related PAHs. PMID:27312275
Dietary Salt Intake and Hypertension
2014-01-01
Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda. PMID:25061468
McSpadden, Kate E; Patrick, Heather; Oh, April Y; Yaroch, Amy L; Dwyer, Laura A; Nebeling, Linda C
2016-01-01
Despite knowing that fruit and vegetable (FV) intake promotes health and well-being, few U.S. adults meet current guidelines. Thus, understanding people's motivation for FV intake is important for predicting dietary behavior. Applying self-determination theory, the goal of this study was to examine the role of social support as a potential moderator of the link between autonomous and controlled motivations and FV intake. Cross-sectional data from 2959 adults in the United States were analyzed. Autonomous motivation and perceived social support were positively associated with FV intake, while controlled motivation was negatively associated with FV intake. Additionally, there was evidence that the negative association between controlled motivation and FV intake was attenuated by higher levels of perceived social support. Findings suggest the need for a more comprehensive approach to understanding the role of motivation in health behaviors like FV intake and the potential roles played by friends and family in these motivational processes. PMID:26321416
An Introduction to Fractional Diffusion
NASA Astrophysics Data System (ADS)
Henry, B. I.; Langlands, T. A. M.; Straka, P.
The mathematical description of diffusion has a long history with many different formulations including phenomenological models based on conservation of mass and constitutive laws; probabilistic models based on random walks and central limit theorems; microscopic stochastic models based on Brownian motion and Langevin equations; and mesoscopic stochastic models based on master equations and Fokker-Planck equations. A fundamental result common to the different approaches is that the mean square displacement of a diffusing particle scales linearly with time. However there have been numerous experimental measurements in which the mean square displacement of diffusing particles scales as a fractional order power law in time. In recent years a great deal of progress has been made in extending the different models for diffusion to incorporate this fractional diffusion. The tools of fractional calculus have proven very useful in these developments, linking together fractional constitutive laws, continuous time random walks, fractional Langevin equations and fractional Brownian motions. These notes provide a tutorial style overview of standard and fractional diffusion processes.
NASA Astrophysics Data System (ADS)
Roussiez, Vincent; Ludwig, Wolfgang; Radakovitch, Olivier; Probst, Jean-Luc; Monaco, André; Charrière, Bruno; Buscail, Roselyne
2011-05-01
The dynamics of sediment-bound metals (Cs, Cu, Ni, Pb, Ti and Zn) were studied off the Têt River (western Gulf of Lion), a typical Mediterranean coastal river punctuated by short and violent flash-floods. Spatial and temporal sampling strategies were combined to elucidate the fate of these elements in response to both the riverine sediment input and the offshore transport of these sediments through hydrodynamics. Our results show the temporal entrapment of riverborne particles and associated metals, consecutively to a major flood event, in the nearshore sedimentary unit called prodelta. Here, deposition and resuspension mechanisms define a sedimentological cycle that could be followed completely in this study. In terms of speciation between reactive (labile) and residual fractions along the fluvio-deltaic continuum, our results show that Cu, Pb and Zn are the most labile (potentially mobile) metals in the river, in accordance with their contributions from anthropogenic sources. But in the marine surficial sediments, two main behaviours can be discriminated when compared to the riverine suspended particulate matter. While Pb and Zn depict rather a constant labile fraction, Cu is characterized by decreasing levels (up to 50% difference). In terms of environmental impact, these contrasting trends have direct repercussions for the contaminant dispersal in the coastal area. Whereas Pb and Zn conserve their enhanced levels because of their stronger affinity with fine sediments, Cu is marked by the entire loss of its anthropogenic component that is progressively transferred to the dissolved phase, likely mediated by organic ligands. We ascribe these behaviours to different post-depositional partition mechanisms with respect to oxidation of the particulate organic phase at the bottom sediment/water interface. Also, analysis of one sediment core from the prodelta indicates that these early diagenetic processes govern the chemical forms of land-derived contaminants
Power Plant Water Intake Assessment.
ERIC Educational Resources Information Center
Zeitoun, Ibrahim H.; And Others
1980-01-01
In order to adequately assess the impact of power plant cooling water intake on an aquatic ecosystem, total ecosystem effects must be considered, rather than merely numbers of impinged or entrained organisms. (Author/RE)
Fiber Intake and Childhood Appendicitis.
ERIC Educational Resources Information Center
Brender, Jean D.; And Others
1985-01-01
Parents of 135 children with appendicitis and of 212 comparison children were interviewed about their children's diet. Results suggest that a liberal intake of whole-grain breads and cereals may decrease the risk of appendicitis during childhood. (KH)
Ecological study for refrigerator use, salt, vegetable, and fruit intakes, and gastric cancer.
Park, Boyoung; Shin, Aesun; Park, Sue K; Ko, Kwang-Pil; Ma, Seung Hyun; Lee, Eun-Ha; Gwack, Jin; Jung, En-Joo; Cho, Lisa Y; Yang, Jae Jeong; Yoo, Keun-Young
2011-11-01
We used an ecological approach to determine the correlation between vegetable, fruit and salt intakes, refrigerator use, and gastric cancer mortality in Korean population. Information on fruit and vegetable intakes per capita from the National Health and Nutrition Survey, death certificate data from the National Statistical office, refrigerator per household data from Korean Statistical Information Service, and salt/sodium intake data from a cross-sectional survey were utilized. Correlation coefficients were calculated between vegetable and fruit intakes, refrigerator per household, and gastric cancer mortality and between salt and sodium intakes, and gastric cancer mortality and incidence in the four areas. With 5, 10, and 15 years lag time, refrigerator usage and fruit intake were negatively associated with gastric cancer mortality (p < 0.01), but vegetable intake was not associated with gastric cancer mortality. When estimates of salt/sodium intake evaluated by 24-h urine collection in four areas of Korea were compared to the gastric cancer mortality and incidence in these regions, positive correlation was shown between salt/sodium intake, and gastric cancer incidence and mortality. Negative associations between refrigerator use, fruit intake, and gastric cancer mortality and positive associations between salt/sodium intake and gastric cancer mortality and incidence were suggested. PMID:21805052
Initialized Fractional Calculus
NASA Technical Reports Server (NTRS)
Lorenzo, Carl F.; Hartley, Tom T.
2000-01-01
This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.
Jurjanz, S; Germain, K; Juin, H; Jondreville, C
2015-05-01
Free-range birds such as organic broilers may ingest soil and plants during exploration. The estimation of such intakes is of great interest to quantify possible nutritional supplies and also to evaluate the risk of exposure to parasites or to environmental contaminants. Marker-based techniques are now available and would allow to quantify plant and, especially, soil intake in free-range birds, and this quantification was the aim of this study. Methodologically, the proportion of plants in diet intake was determined first using a method based on n-alkanes. Subsequently, the fraction of soil in the total intake was estimated with a second marker, acid-insoluble ash. This approach was carried out to estimate ingested amounts of plants and soil for five successive flocks of organic broilers, exploring grass-covered yards or those under trees, at two time points for each yard: 51 and 64 days of age. Each factor combination (yard type×period=flock number×age) was repeated on two different yards of 750 broilers each. The birds' plant intake varied widely, especially on grass-covered yards. The proportion of plant intake was significantly higher on grass-covered plots than under trees and was also affected, but to a lesser extent, by age or flock number. The ingestion of plants would generally not exceed 11 g of DM daily, except two extreme outliers of nearly 30 g. The daily plant intake under trees tended to be lower and never exceeded 7 g of DM. The amount of ingested plants increased significantly for spring flocks. It increased slightly but significantly with age. The proportion of ingested soil was significantly higher under trees than on grass-covered yards. Dry soil intake was generally low with not more than 3 g per day. Only in adverse conditions - that is, older birds exploring yards under trees in winter - soil intake reached the extreme value of nearly 5 g. Broilers on yards under trees ingested significantly more soil than on grass-covered yards with least
NASA Astrophysics Data System (ADS)
Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua
2015-07-01
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua
2015-07-15
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
Relationship between fractional calculus and fractional Fourier transform
NASA Astrophysics Data System (ADS)
Zhang, Yanshan; Zhang, Feng; Lu, Mingfeng
2015-09-01
The fractional calculus (FC) deals with integrals and derivatives of arbitrary (i.e., non-integer) order, and shares its origins with classical integral and differential calculus. The fractional Fourier transform (FRFT), which has been found having many applications in optics and other areas, is a generalization of the usual Fourier transform. The FC and the FRFT are two of the most interesting and useful fractional areas. In recent years, it appears many papers on the FC and FRFT, however, few of them discuss the connection of the two fractional areas. We study their relationship. The relational expression between them is deduced. The expectation of interdisciplinary cross fertilization is our motivation. For example, we can use the properties of the FC (non-locality, etc.) to solve the problem which is difficult to be solved by the FRFT in optical engineering; we can also through the physical meaning of the FRFT optical implementation to explain the physical meaning of the FC. The FC and FRFT approaches can be transposed each other in the two fractional areas. It makes that the success of the fractional methodology is unquestionable with a lot of applications, namely in nonlinear and complex system dynamics and image processing.
Guerrero, Julien; Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle
2015-03-01
Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion. PMID:25333855
Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle
2015-01-01
Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion. PMID:25333855
Low level alcohol intake, cigarette smoking and risk of breast cancer in Asian-American women.
Brown, Linda Morris; Gridley, Gloria; Wu, Anna H; Falk, Roni T; Hauptmann, Michael; Kolonel, Laurence N; West, Dee W; Nomura, Abraham M Y; Pike, Malcolm C; Hoover, Robert N; Ziegler, Regina G
2010-02-01
Studies have shown that breast cancer incidence rates among Asian migrants to the United States approach US incidence rates over several generations, implicating potentially modifiable exposures such as moderate alcohol use that has been linked to excess breast cancer risk in other populations. The goal of this study was to investigate the effect of alcohol intake, primarily low levels, on breast cancer risk in Asian-American women and explore whether smoking and alcohol contributed to the breast cancer incidence rates observed among Asian migrants to the United States. Study subjects in this population-based case-control study included 597 incident cases of breast cancer of Chinese, Japanese, and Filipino ethnicity living in San Francisco-Oakland, Los Angeles, and Oahu, Hawaii, and 966 population controls frequency matched on age, ethnicity, and area of residence. The fraction of smokers and drinkers was significantly higher in women born in Western compared with Eastern countries. However, breast cancer risk was not significantly associated with smoking (odds ratio (OR) = 1.2, 95% confidence interval (95% CI) = 0.9-1.6) or alcohol drinking (OR = 0.9, 95% CI = 0.7-1.1) in this population of low consumers of alcohol (median intake among drinkers in grams per day was 0.48 for cases and 0.40 for controls). These data suggest that low alcohol intake is not related to increased breast cancer risk in Asian-American women and that neither alcohol nor cigarette use contributed to the elevated risks in Asian-American women associated with migration patterns and Westernization. PMID:19597702
MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA
2014-01-01
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series. PMID:26085690
McKenna, Malachi J; McKenna, Mary Clare S; van der Kamp, Susan
2016-01-01
Adequate calcium intake is essential for bone health. Calcium is obtained from dietary sources and supplementation. Knowing the daily dietary calcium intake is helpful in deciding on the need for supplementation. Dietary calcium intake can be estimated quickly and accurately using an approach recommended by the National Osteoporosis Foundation. We sought to evaluate the usefulness of estimating dietary calcium intake by a technologist at the time of attendance for dual-energy X-ray absorptiometry (DXA) scanning. We conducted a retrospective survey of results on estimated dietary calcium intake in adults attending our DXA unit over 2 years (n=5569). We assessed intake with reference to the specifications of the Institute of Medicine according to sex and age. The average intake was 736 mg daily: Young adults had higher intakes than older adults (p<0.001), and men had higher intakes than women (p=0.017). According to Institute of Medicine's specification, we estimate that nearly 45% of Irish women need supplemental intake of 500 mg daily but <4% need supplemental intake of 1000 mg daily. Younger adults are apt to have intakes within, or higher than, the requirement. Having DXA technologists estimate dietary calcium intake at the time of DXA scanning may provide helpful information to the referring clinicians about the need for supplementation. PMID:25934029
Salt intake and hypertension therapy.
Milan, Alberto; Mulatero, Paolo; Rabbia, Franco; Veglio, Franco
2002-01-01
Hypertension is a risk factor for cardiovascular and renal organ damage. Environmental conditions affect the development of high blood pressure (BP), although genetic influences are also important. Current international guidelines recommend reducing dietary sodium to no more than 100 mmol (about 2.4 g sodium or approximately 6 g salt) per day to prevent BP rising; the current intake of sodium in industrialized countries is approximately double the recommended amount. Clinical trials (DASH and TOHP studies) have shown that dietary factors are fundamental in the prevention and control of BP. Low dietary sodium intake is particularly effective in preventing hypertension in subjects with an increased risk such as the overweight, borderline hypertensives or the elderly. A low-salt diet combined with anti-hypertensive therapies facilitates BP reduction independent of race. The hypotensive effect of calcium channel blockers is less dependent on salt intake than other drugs, such as ACE inhibitors or diuretics. Reduced sodium intake associated with other dietary changes (such as weight loss, and increasing potassium, calcium and magnesium intake) are important instruments for the prevention and therapy of hypertension. PMID:11936420
2011-01-01
Background Enhancement of antimicrobial plant products e.g. pomegranate extract by copper (II) sulphate is known. Such combinations have applications in various settings, including the identification of novel compositions to study, treat and control infection. Methods A combination of white tea (WT) (made allowing 10 minutes infusion time at 100°C) was combined with 4.8 mM copper (II) sulphate and tested for antimicrobial effect on the viability of Staphylococcus aureus NCTC 06571. Comparisons were made with green (GT) and black (BT) teas. A WT sub-fraction (WTF < 1000 Da) was tested with copper (II) sulphate and 4.8 mM vitamin C. pH measurements of samples were taken for controls and to observe any changes due to tea/agent interaction. Catalase was used to investigate hydrogen peroxide release. UV-vis. was used to compare WT and WTF. Results A 30 minute incubation at room temperature of copper (II) sulphate alone and combined with WT reduced the viability of S. aureus NCTC 06571 by c.a 1 log10 cfu mL-1. GT and BT with copper (II) sulphate negated activity to buffer values. Combined with copper (II) sulphate, vitamin C, WTF and, vitamin C plus WTF all reduced the viability of S. aureus NCTC 06571 by c.a. 3.5 log10 cfu mL-1. Independent experiments showed the results were not due to pH effects. Adding WT or WTF to copper (II) sulphate resulted in increased acidity. Copper (II) sulphate alone and combined with WT required c.a 300 μg mL-1 (final concentration) catalase to restore S. aureus viability, WTF with copper (II) sulphate and added vitamin C required c.a 600 μg mL-1. WT and WTF UV-visible spectra were similar. Conclusions WT showed no efficacy in the combinations tested. WTF was enhanced with copper (II) sulphate and further with vitamin C. WT and WTF increased acidity of copper (II) sulphate possibly via the formation of chemical complexes. The difference in WT/WTF absorbance possibly represented substances less concentrated or absent in WTF
Measuring Outdoor Air Intake Rates into Existing Building
Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik
2009-04-16
Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.
FRACTIONAL INTEGRATION TOOLBOX
Marinov, Toma M.; Ramirez, Nelson; Santamaria, Fidel
2014-01-01
The problems formulated in the fractional calculus framework often require numerical fractional integration/differentiation of large data sets. Several existing fractional control toolboxes are capable of performing fractional calculus operations, however, none of them can efficiently perform numerical integration on multiple large data sequences. We developed a Fractional Integration Toolbox (FIT), which efficiently performs fractional numerical integration/differentiation of the Riemann-Liouville type on large data sequences. The toolbox allows parallelization and is designed to be deployed on both CPU and GPU platforms. PMID:24812536
Development of a model to predict forage intake by grazing cattle.
Hyer, J C; Oltjen, J W; Galyean, M L
1991-02-01
A mathematical model to predict daily DMI and account for effects of energy supplementation on forage intake has been developed in several stages. A previously evaluated dynamic rumen model for sheep was adopted as the fermentation component of the intake model. Intake was adjusted to reach a given level of DM fill, which is the sum of the concentrations of each of the dietary fractions within the rumen. Differential equations described the rate of change of each nutrient fraction. Genetic size scaling rules based on mature body size relationships were used to adjust rate and fill parameters of the intake model from sheep to beef cattle. Nutrient fractions were partitioned into those that flow at the particulate passage rate vs the fluid passage rate. Forty-two data points representing perennial ryegrass, wheat pasture and range grasses were used to parameterize and evaluate the model. The model was relatively sensitive to the coefficient relating DMI to particulate rate of passage, the rate constant for the use of the potentially degraded fiber fraction of the forage, and to the composition constants for the amount of carbohydrate and nitrogen in the microbial mass. Relative insensitivity was observed for starch and protein nutrient use rate constants, for the coefficient relating DMI to fluid passage rate, and for constants relating to the growth of the microbial mass in the rumen. Feed intake of grazing cattle may be predicted by mechanistic models describing various nutrients' contribution to ruminal fill. PMID:2016209
Hotz, Christine; Pelto, Gretel; Armar-Klemesu, Margaret; Ferguson, Elaine F; Chege, Peter; Musinguzi, Enock
2015-12-01
Several types of interventions can be used to improve nutrient intake adequacy in infant and young child (IYC) diets, including fortified foods, home fortification, nutrition education and behaviour change communication (BCC) in addition to agricultural and market-based strategies. However, the appropriate selection of interventions depends on the social, cultural, physical and economic context of the population. Derived from two rural Kenyan populations, this analysis combined information from: (1) a quantitative analysis to derive a set of food-based recommendations (FBRs) to fill nutrient intake gaps in IYC diets and identify 'problem nutrients' for which intake gaps require solutions beyond currently available foods and dietary patterns, and (2) an ethnographic qualitative analysis to identify contextual factors posing opportunities or constraints to implementing the FBRs, including perceptions of cost, convenience, accessibility and appropriateness of the recommended foods for IYC diets and other social or physical factors that determine accessibility of those foods. Opportunities identified included BCC to increase the acceptability and utilisation of green leafy vegetables (GLV) and small fish and agronomic interventions to increase the productivity of GLV and millet. Value chains for millet, beans, GLV, milk and small fish should be studied for opportunities to increase their accessibility in local markets. Processor-level interventions, such as partially cooked fortified dry porridge mixes or unfortified cereal mixes incorporating millet and beans, may increase the accessibility of foods that provide increased amounts of the problem nutrients. Multi-sectoral actors and community stakeholders should be engaged to assess the feasibility of implementing these locally appropriate strategies. PMID:26778801
Energy density, energy intake regulation and body weight
Technology Transfer Automated Retrieval System (TEKTRAN)
Obesity is one of the major health crises of our time. The majority of adult Americans are now either overweight or obese, and recent research indicates that obesity is approaching smoking as the major cause of disability and premature death. National improvements in dietary intake, and in particu...
Fractional characteristic times and dissipated energy in fractional linear viscoelasticity
NASA Astrophysics Data System (ADS)
Colinas-Armijo, Natalia; Di Paola, Mario; Pinnola, Francesco P.
2016-08-01
In fractional viscoelasticity the stress-strain relation is a differential equation with non-integer operators (derivative or integral). Such constitutive law is able to describe the mechanical behavior of several materials, but when fractional operators appear, the elastic and the viscous contribution are inseparable and the characteristic times (relaxation and retardation time) cannot be defined. This paper aims to provide an approach to separate the elastic and the viscous phase in the fractional stress-strain relation with the aid of an equivalent classical model (Kelvin-Voigt or Maxwell). For such equivalent model the parameters are selected by an optimization procedure. Once the parameters of the equivalent model are defined, characteristic times of fractional viscoelasticity are readily defined as ratio between viscosity and stiffness. In the numerical applications, three kinds of different excitations are considered, that is, harmonic, periodic, and pseudo-stochastic. It is shown that, for any periodic excitation, the equivalent models have some important features: (i) the dissipated energy per cycle at steady-state coincides with the Staverman-Schwarzl formulation of the fractional model, (ii) the elastic and the viscous coefficients of the equivalent model are strictly related to the storage and the loss modulus, respectively.
Fractionalized gapless quantum vortex liquids
NASA Astrophysics Data System (ADS)
Wang, Chong; Senthil, T.
2015-05-01
The standard theoretical approach to gapless spin liquid phases of two-dimensional frustrated quantum antiferromagnets invokes the concept of fermionic slave particles into which the spin fractionalizes. As an alternate we explore different kinds of gapless spin liquid phases in frustrated quantum magnets with X Y anisotropy where the vortex of the spin fractionalizes into gapless itinerant fermions. The resulting gapless fractionalized vortex liquid phases are studied within a slave particle framework that is dual to the usual one. We demonstrate the stability of some such phases and describe their properties. We give an explicit construction in an X Y -spin-1 system on triangular lattice, and interpret it as a critical phase in the vicinity of spin-nematic states.
ERIC Educational Resources Information Center
Graham, Alan; Graham, Louise
2003-01-01
Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)
[Bone and Nutrition. Bone and phosphorus intake].
Arai, Hidekazu; Sakuma, Masae
2015-07-01
Phosphorus is necessary for bone mineralization. Although adequate phosphorus intake is essential for skeletal mineralization, it is reported that excessive phosphorus intake can induce deleterious effect on bone. Recently, since the Japanese diet has been westernized, phosphorus intake by the meat and dairy products has increased. Furthermore, along with the development of processed foods, excessive intake of inorganic phosphorus from food additives has become a problem. An adverse effect on parathyroid hormone (PTH) secretion from high phosphorus intake was seen only when calcium intake was inadequate. Dietary calcium to phosphorus ratio can be considered as one of the indicators that can predict the health of the bone. PMID:26119308
Sharma, Manisha; Mukhopadhyay, Arundhati; Gupta, Vibha; Pental, Deepak; Pradhan, Akshay K.
2016-01-01
Among the different types of methionine-derived aliphatic glucosinolates (GS), sinigrin (2-propenyl), the final product in 3C GS biosynthetic pathway is considered very important as it has many pharmacological and therapeutic properties. In Brassica species, the candidate gene regulating synthesis of 3C GS remains ambiguous. Earlier reports of GSL-PRO, an ortholog of Arabidopsis thaliana gene At1g18500 as a probable candidate gene responsible for 3C GS biosynthesis in B. napus and B. oleracea could not be validated in B. juncea through genetic analysis. In this communication, we report the isolation and characterization of the gene CYP79F1, an ortholog of A. thaliana gene At1g16410 that is involved in the first step of core GS biosynthesis. The gene CYP79F1 in B. juncea showed presence-absence polymorphism between lines Varuna that synthesizes sinigrin and Heera virtually free from sinigrin. Using this presence-absence polymorphism, CYP79F1 was mapped to the previously mapped 3C GS QTL region (J16Gsl4) in the LG B4 of B. juncea. In Heera, the gene was observed to be truncated due to an insertion of a ~4.7 kb TE like element leading to the loss of function of the gene. Functional validation of the gene was carried out through both genetic and transgenic approaches. An F2 population segregating only for the gene CYP79F1 and the sinigrin phenotype showed perfect co-segregation. Finally, genetic transformation of a B. juncea line (QTL-NIL J16Gsl4) having high seed GS but lacking sinigrin with the wild type CYP79F1 showed the synthesis of sinigrin validating the role of CYP79F1 in regulating the synthesis of 3C GS in B. juncea. PMID:26919200
Calcium Intake: A Lifelong Proposition.
ERIC Educational Resources Information Center
Amschler, Denise H.
1985-01-01
This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)
Federal Register 2010, 2011, 2012, 2013, 2014
2010-01-20
...; ] DEPARTMENT OF JUSTICE Bureau of Prisons 28 CFR Part 522 RIN 1120-AB47 Intake Screening AGENCY: Bureau of Prisons, Justice. ACTION: Proposed rule. SUMMARY: In this document, the Bureau of Prisons (Bureau... to the Rules Unit, Office of General Counsel, Bureau of Prisons, 320 First Street, NW.,...
Protein intake and bone health.
Bonjour, Jean-Philippe
2011-03-01
Adequate nutrition plays an important role in the development and maintenance of bone structures resistant to usual mechanical stresses. In addition to calcium in the presence of an adequate supply of vitamin D, dietary proteins represent key nutrients for bone health and thereby function in the prevention of osteoporosis. Several studies point to a positive effect of high protein intake on bone mineral density or content. This fact is associated with a significant reduction in hip fracture incidence, as recorded in a large prospective study carried out in a homogeneous cohort of postmenopausal women. Low protein intake (< 0.8 g/kg body weight/day) is often observed in patients with hip fractures and an intervention study indicates that following orthopedic management, protein supplementation attenuates post-fracture bone loss, tends to increase muscle strength, and reduces medical complications and rehabilitation hospital stay. There is no evidence that high protein intake per se would be detrimental for bone mass and strength. Nevertheless, it appears reasonable to avoid very high protein diets (i. e. more than 2.0 g/kg body weight/day) when associated with low calcium intake (i. e. less than 600 mg/day). In the elderly, taking into account the attenuated anabolic response to dietary protein with ageing, there is concern that the current dietary protein recommended allowance (RDA), as set at 0.8 g/kg body weight/day, might be too low for the primary and secondary prevention of fragility fractures. PMID:22139564
Pangalos, Constantinos; Hagnefelt, Birgitta; Lilakos, Konstantinos; Konialis, Christopher
2016-01-01
Background. Fetal malformations and other structural abnormalities are relatively frequent findings in the course of routine prenatal ultrasonographic examination. Due to their considerable genetic and clinical heterogeneity, the underlying genetic cause is often elusive and the resulting inability to provide a precise diagnosis precludes proper reproductive and fetal risk assessment. We report the development and first applications of an expanded exome sequencing-based test, coupled to a bioinformatics-driven prioritization algorithm, targeting gene disorders presenting with abnormal prenatal ultrasound findings. Methods. We applied the testing strategy to14 euploid fetuses, from 11 on-going pregnancies and three products of abortion, all with various abnormalities or malformations detected through prenatal ultrasound examination. Whole exome sequencing (WES) was followed by variant prioritization, utilizing a custom analysis pipeline (Fetalis algorithm), targeting 758 genes associated with genetic disorders which may present with abnormal fetal ultrasound findings. Results. A definitive or highly-likely diagnosis was made in 6 of 14 cases (43%), of which 3 were abortuses (Ellis-van Creveld syndrome, Ehlers-Danlos syndrome and Nemaline myopathy 2) and 3 involved on-going pregnancies (Citrullinemia, Noonan syndrome, PROKR2-related Kallmann syndrome). In the remaining eight on-going pregnancy cases (57%), a ZIC1 variant of unknown clinical significance was detected in one case, while in seven cases testing did not reveal any pathogenic variant(s). Pregnancies were followed-up to birth, resulting in one neonate harboring the PROKR2 mutation, presenting with isolated minor structural cardiac abnormalities, and in seven apparently healthy neonates. Discussion. The expanded targeted exome sequencing-based approach described herein (Fetalis), provides strong evidence suggesting a definite and beneficial increase in our diagnostic capabilities in prenatal diagnosis of
Pangalos, Constantinos; Hagnefelt, Birgitta; Lilakos, Konstantinos
2016-01-01
Background. Fetal malformations and other structural abnormalities are relatively frequent findings in the course of routine prenatal ultrasonographic examination. Due to their considerable genetic and clinical heterogeneity, the underlying genetic cause is often elusive and the resulting inability to provide a precise diagnosis precludes proper reproductive and fetal risk assessment. We report the development and first applications of an expanded exome sequencing-based test, coupled to a bioinformatics-driven prioritization algorithm, targeting gene disorders presenting with abnormal prenatal ultrasound findings. Methods. We applied the testing strategy to14 euploid fetuses, from 11 on-going pregnancies and three products of abortion, all with various abnormalities or malformations detected through prenatal ultrasound examination. Whole exome sequencing (WES) was followed by variant prioritization, utilizing a custom analysis pipeline (Fetalis algorithm), targeting 758 genes associated with genetic disorders which may present with abnormal fetal ultrasound findings. Results. A definitive or highly-likely diagnosis was made in 6 of 14 cases (43%), of which 3 were abortuses (Ellis-van Creveld syndrome, Ehlers-Danlos syndrome and Nemaline myopathy 2) and 3 involved on-going pregnancies (Citrullinemia, Noonan syndrome, PROKR2-related Kallmann syndrome). In the remaining eight on-going pregnancy cases (57%), a ZIC1 variant of unknown clinical significance was detected in one case, while in seven cases testing did not reveal any pathogenic variant(s). Pregnancies were followed-up to birth, resulting in one neonate harboring the PROKR2 mutation, presenting with isolated minor structural cardiac abnormalities, and in seven apparently healthy neonates. Discussion. The expanded targeted exome sequencing-based approach described herein (Fetalis), provides strong evidence suggesting a definite and beneficial increase in our diagnostic capabilities in prenatal diagnosis of
Fractional quantum Hall effect revisited
NASA Astrophysics Data System (ADS)
Jacak, J.; Łydżba, P.; Jacak, L.
2015-10-01
The topology-based explanation of the fractional quantum Hall effect (FQHE) is summarized. The cyclotron braid subgroups crucial for this approach are introduced in order to identify the origin of the Laughlin correlations in 2D (two-dimensional) Hall systems. Flux-tubes and vortices for composite fermions in their standard constructions are explained in terms of cyclotron braids. The derivation of the hierarchy of the FQHE is proposed by mapping onto the integer effect within the topology-based approach. The experimental observations of the FQHE supporting the cyclotron braid picture are reviewed with a special attention paid to recent experiments with a suspended graphene. The triggering role of a carrier mobility for organization of the fractional state in Hall configuration is emphasized. The prerequisites for the FQHE are indicated including topological conditions substantially increasing the previously accepted set of physical necessities. The explanation of numerical studies by exact diagonalizations of the fractional Chern insulator states is formulated in terms of the topology condition applied to the Berry field flux quantization. Some new ideas withz regard to the synthetic fractional states in the optical lattices are also formulated.
Yu,P.
2007-01-01
Studying the secondary structure of proteins leads to an understanding of the components that make up a whole protein, and such an understanding of the structure of the whole protein is often vital to understanding its digestive behaviour and nutritive value in animals. The main protein secondary structures are the {alpha}-helix and {beta}-sheet. The percentage of these two structures in protein secondary structures influences protein nutritive value, quality and digestive behaviour. A high percentage of {beta}-sheet structure may partly cause a low access to gastrointestinal digestive enzymes, which results in a low protein value. The objectives of the present study were to use advanced synchrotron-based Fourier transform IR (S-FTIR) microspectroscopy as a new approach to reveal the molecular chemistry of the protein secondary structures of feed tissues affected by heat-processing within intact tissue at a cellular level, and to quantify protein secondary structures using multicomponent peak modelling Gaussian and Lorentzian methods, in relation to protein digestive behaviours and nutritive value in the rumen, which was determined using the Cornell Net Carbohydrate Protein System. The synchrotron-based molecular chemistry research experiment was performed at the National Synchrotron Light Source at Brookhaven National Laboratory, US Department of Energy. The results showed that, with S-FTIR microspectroscopy, the molecular chemistry, ultrastructural chemical make-up and nutritive characteristics could be revealed at a high ultraspatial resolution ({approx}10 {mu}m). S-FTIR microspectroscopy revealed that the secondary structure of protein differed between raw and roasted golden flaxseeds in terms of the percentages and ratio of {alpha}-helixes and {beta}-sheets in the mid-IR range at the cellular level. By using multicomponent peak modelling, the results show that the roasting reduced (P <0.05) the percentage of {alpha}-helixes (from 47.1% to 36.1%: S
Avoidant/Restrictive Food Intake Disorder
... Professional Version Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ... they eat. Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ...
Fractionalized topological defects in optical lattices
NASA Astrophysics Data System (ADS)
Zhang, Xing-Hai; Fan, Wen-Jun; Shi, Jin-Wei; Kou, Su-Peng
2015-10-01
Topological objects are interesting topics in various fields of physics ranging from condensed matter physics to the grand unified and superstring theories. Among those, ultracold atoms provide a playground to study the complex topological objects. In this paper we present a proposal to realize an optical lattice with stable fractionalized topological objects. In particular, we generate the fractionalized topological fluxes and fractionalized skyrmions on two-dimensional optical lattices and fractionalized monopoles on three-dimensional optical lattices. These results offer a new approach to study the quantum many-body systems on optical lattices of ultracold quantum gases with controllable topological defects, including dislocations, topological fluxes and monopoles.
Hlaing, Lwin Mar; Fahmida, Umi; Htet, Min Kyaw; Utomo, Budi; Firmansyah, Agus; Ferguson, Elaine L
2016-07-01
Poor feeding practices result in inadequate nutrient intakes in young children in developing countries. To improve practices, local food-based complementary feeding recommendations (CFR) are needed. This cross-sectional survey aimed to describe current food consumption patterns of 12-23-month-old Myanmar children (n 106) from Ayeyarwady region in order to identify nutrient requirements that are difficult to achieve using local foods and to formulate affordable and realistic CFR to improve dietary adequacy. Weekly food consumption patterns were assessed using a 12-h weighed dietary record, single 24-h recall and a 5-d food record. Food costs were estimated by market surveys. CFR were formulated by linear programming analysis using WHO Optifood software and evaluated among mothers (n 20) using trial of improved practices (TIP). Findings showed that Ca, Zn, niacin, folate and Fe were 'problem nutrients': nutrients that did not achieve 100 % recommended nutrient intake even when the diet was optimised. Chicken liver, anchovy and roselle leaves were locally available nutrient-dense foods that would fill these nutrient gaps. The final set of six CFR would ensure dietary adequacy for five of twelve nutrients at a minimal cost of 271 kyats/d (based on the exchange rate of 900 kyats/USD at the time of data collection: 3rd quarter of 2012), but inadequacies remained for niacin, folate, thiamin, Fe, Zn, Ca and vitamin B6. TIP showed that mothers believed liver and vegetables would cause worms and diarrhoea, but these beliefs could be overcome to successfully promote liver consumption. Therefore, an acceptable set of CFR were developed to improve the dietary practices of 12-23-month-old Myanmar children using locally available foods. Alternative interventions such as fortification, however, are still needed to ensure dietary adequacy of all nutrients. PMID:26696232
Urinary excretion and daily intake rates of diethyl phthalate in the general Canadian population.
Saravanabhavan, Gurusankar; Walker, Mike; Guay, Mireille; Aylward, Lesa
2014-12-01
We have analyzed the trends in the body-weight-adjusted urinary monoethyl phthalate (MEP) concentrations and the diethyl ethyl phthalate (DEP) daily intake estimates in the general Canadian population (aged 6-49 years) using the Canadian Health Measures Survey 2007-2009 dataset. The creatinine correction approach, as well as the urine volume approach in a simple one compartment model were used to calculate the daily urinary MEP excretion rates and DEP intake rates in individual survey participants. Using multiple regression models, we have estimated least square geometric means (LSGMs) of body-weight-adjusted MEP concentration, daily excretion and intake rates among different age groups and sex. We observed that body weight affects the trends in the MEP concentrations significantly among children (aged 6-11 years), adolescents (aged 12-19 years) and adults (aged 20-49 years). The body-weight-adjusted MEP concentrations in children were significantly higher than those in adults. On the other hand the DEP daily intakes in children were significantly lower than those in adults. We did not observe any differences in the DEP daily intake rates between males and females. Although the urinary MEP concentrations are correlated well with DEP daily intake estimates in the overall population, one should be cautious when directly using the urinary concentrations to compare the intake trends in the sub-populations (e.g. children vs. adults) as these trends are governed by additional physiological factors. The DEP daily intake calculated using the creatinine approach and that using the urine volume approach were similar to each other. The estimated geometric mean and 95th percentile of DEP daily intake in the general Canadian population are 2 and 20 μg/kg-bw/day, respectively. These daily intake estimates are significantly lower than the US Environmental Protection Agency's oral reference dose of 800 μg/kg-bw/day. PMID:25217994
Dividing Fractions: A Pedagogical Technique
ERIC Educational Resources Information Center
Lewis, Robert
2016-01-01
When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…
Evaluating fractionated space systems - Status
NASA Astrophysics Data System (ADS)
Cornford, S.; Jenkins, S.; Wall, S.; Cole, B.; Bairstow, B.; Rouquette, N.; Dubos, G.; Ryan, T.; Zarifian, P.; Boutwell, J.
DARPA has funded a number of teams to further refine its Fractionated Spacecraft vision. Several teams, including this team led by JPL, have been tasked to develop a tool for the evaluation of the Business case for a fractionated system architecture. This evaluation is to understand under what conditions and constraints the fractionated architecture make more sense (in a cost/benefit sense) than the traditional monolithic paradigm. Our approach to this evaluation is to generate and evaluate a variety of trade space options. These options include various sets of stimuli, various degrees of fractionation and various subsystem element properties. The stimuli include many not normally modeled such as technology obsolescence, funding profile changes and changes in mission objectives during the mission itself. The degrees of fractionation enable various traditional subsystem elements to be distributed across different free flyers which then act in concert as needed. This will enable key technologies to be updated as need dictates and availability allows. We have described our approach in a previous IEEE Aerospace conference paper but will briefly summarize here. Our approach to generate the Business Case evaluation is to explicitly model both the implementation and operation phases for the life cycle of a fractionated constellation. A variety of models are integrated into the Phoenix ModelCenter framework and are used to generate various intermediate data which is aggregated into the Present Strategic Value (PSV). The PSV is essentially the value (including the value of the embedded real options) minus the cost. These PSVs are calculated for a variety of configurations and scenarios including variations of various stimuli or uncertainties (e.g. supply chain delays, launch vehicle failures and orbital debris events). There are various decision options (e.g. delay, accelerate, cancel) which can now be exercised for each stimulus. We can compute the PSV for the various comb
Intake of total and added sugars and nutrient dilution in Australian children and adolescents.
Louie, Jimmy Chun Yu; Tapsell, Linda C
2015-12-14
This analysis aimed to examine the association between intake of sugars (total or added) and nutrient intake with data from a recent Australian national nutrition survey, the 2007 Australian National Children's Nutrition and Physical Activity Survey (2007ANCNPAS). Data from participants (n 4140; 51 % male) who provided 2×plausible 24-h recalls were included in the analysis. The values on added sugars for foods were estimated using a previously published ten-step systematic methodology. Reported intakes of nutrients and foods defined in the 2007ANCNPAS were analysed by age- and sex-specific quintiles of %energy from added sugars (%EAS) or %energy from total sugars (%ETS) using ANCOVA. Linear trends across the quintiles were examined using multiple linear regression. Logistic regression analysis was used to calculate the OR of not meeting a specified nutrient reference values for Australia and New Zealand per unit in %EAS or %ETS. Analyses were adjusted for age, sex, BMI z-score and total energy intake. Small but significant negative associations were seen between %EAS and the intakes of most nutrient intakes (all P<0·001). For %ETS the associations with nutrient intakes were inconsistent; even then they were smaller than that for %EAS. In general, higher intakes of added sugars were associated with lower intakes of most nutrient-rich, 'core' food groups and higher intakes of energy-dense, nutrient-poor 'extra' foods. In conclusion, assessing intakes of added sugars may be a better approach for addressing issues of diet quality compared with intakes of total sugars. PMID:26411397
Campbell, Ian C.; Coudrillier, Baptiste; Mensah, Johanne; Abel, Richard L.; Ethier, C. Ross
2015-01-01
The lamina cribrosa (LC) is a tissue in the posterior eye with a complex trabecular microstructure. This tissue is of great research interest, as it is likely the initial site of retinal ganglion cell axonal damage in glaucoma. Unfortunately, the LC is difficult to access experimentally, and thus imaging techniques in tandem with image processing have emerged as powerful tools to study the microstructure and biomechanics of this tissue. Here, we present a staining approach to enhance the contrast of the microstructure in micro-computed tomography (micro-CT) imaging as well as a comparison between tissues imaged with micro-CT and second harmonic generation (SHG) microscopy. We then apply a modified version of Frangi's vesselness filter to automatically segment the connective tissue beams of the LC and determine the orientation of each beam. This approach successfully segmented the beams of a porcine optic nerve head from micro-CT in three dimensions and SHG microscopy in two dimensions. As an application of this filter, we present finite-element modelling of the posterior eye that suggests that connective tissue volume fraction is the major driving factor of LC biomechanics. We conclude that segmentation with Frangi's filter is a powerful tool for future image-driven studies of LC biomechanics. PMID:25589572
Campbell, Ian C; Coudrillier, Baptiste; Mensah, Johanne; Abel, Richard L; Ethier, C Ross
2015-03-01
The lamina cribrosa (LC) is a tissue in the posterior eye with a complex trabecular microstructure. This tissue is of great research interest, as it is likely the initial site of retinal ganglion cell axonal damage in glaucoma. Unfortunately, the LC is difficult to access experimentally, and thus imaging techniques in tandem with image processing have emerged as powerful tools to study the microstructure and biomechanics of this tissue. Here, we present a staining approach to enhance the contrast of the microstructure in micro-computed tomography (micro-CT) imaging as well as a comparison between tissues imaged with micro-CT and second harmonic generation (SHG) microscopy. We then apply a modified version of Frangi's vesselness filter to automatically segment the connective tissue beams of the LC and determine the orientation of each beam. This approach successfully segmented the beams of a porcine optic nerve head from micro-CT in three dimensions and SHG microscopy in two dimensions. As an application of this filter, we present finite-element modelling of the posterior eye that suggests that connective tissue volume fraction is the major driving factor of LC biomechanics. We conclude that segmentation with Frangi's filter is a powerful tool for future image-driven studies of LC biomechanics. PMID:25589572
Leonenko, Nikolai N.; Meerschaert, Mark M.
2013-01-01
Pearson diffusions are governed by diffusion equations with polynomial coefficients. Fractional Pearson diffusions are governed by the corresponding time-fractional diffusion equation. They are useful for modeling sub-diffusive phenomena, caused by particle sticking and trapping. This paper provides explicit strong solutions for fractional Pearson diffusions, using spectral methods. It also presents stochastic solutions, using a non-Markovian inverse stable time change. PMID:23626377
A STATE-OF-THE-ART REPORT ON INTAKE TECHNOLOGIES
The report presents an updated evaluation of mechanisms and intake designs for reducing the number of fish entrained and impinged at water intake facilities. These mechanisms consist of intake configurations, behavioral barriers for guiding fish past intake entrances, physical sc...
Role of renal nerves in compensatory adaptation to chronic reductions in sodium intake
Mizelle, H.L.; Hall, J.E.; Woods, L.L.; Montani, J.P.; Dzielak, D.J.; Pan, Y.J.
1987-02-01
The aim of this study was to investigate the importance of the renal nerves in adaptation to chronic reductions in sodium intake. Conscious dogs with unilateral or bilateral renal denervation were studied. Kidney function was determined by the clearance (/sup 125/I)-contrast media. In dogs studied before and after bilateral denervation, there were no differences in urine volume (UO), Na excretion (U/sub Na/V), or fractional reabsorption of Li, between innervated and denervated kidneys on either normal (80 meg/day) or low Na intake (5 meq/day, 15 days). Plasma renin activity (PRA) was attenuated following denervation on both normal and low Na intake. There was no difference in UO between innervated and denervated kidneys on normal or low Na intake. U/sub Na/V averaged 33.6 +/- 1.3 and 37.6 +/- 2.1 meq/day in innervated and denervated kidneys, respectively, on normal Na intake and 3.5 +/- 0.5 and 4.0 +/- 0.4 meq/day in innervated and denervated kidneys on low Na intake. Norepinephrine content was reduced by 99 +/- 1% in denervated kidneys. These results suggest that, although the renal nerves may play a small role in controlling U/sub Na/V during normal Na, the presence of the nerves is not essential for adaptation to chronic reductions in Na intake. However, the renal nerves may play a role in long-term control of renin secretion.
Association Between Low Dairy Intake During Pregnancy and Risk of Small-for-Gestational-Age Infants.
Olmedo-Requena, Rocío; Amezcua-Prieto, Carmen; Luna-Del-Castillo, Juan de Dios; Lewis-Mikhael, Anne-Mary; Mozas-Moreno, Juan; Bueno-Cavanillas, Aurora; Jiménez-Moleón, José Juan
2016-06-01
Background Inadequate maternal nutrition is regarded as one of the most important indicators of fetal growth. The aim of this study was to analyze the associated risk of having a small for gestational age (SGA) infant according to the mother's dairy intake during the first half of pregnancy. Methods A prospective cohort study was performed using 1175 healthy pregnant women selected from the catchment area of Virgen de las Nieves University Hospital, Granada (Spain). SGA was defined as neonates weighing less than the 10th percentile, adjusted for gestational age. Factors associated with SGA were analyzed using logistic regression models. Population attributable fractions of SGA according to dairy intake were estimated. Results Dairy intake among women who gave birth to SGA infants was 513.9, versus 590.3 g/day for women with appropriate size for gestational age infants (P = 0.003). An increased intake of dairy products by 100 g/day during the first half of pregnancy decreased the risk of having a SGA infant by 11.0 %, aOR = 0.89 (0.83, 0.96). A dose-response gradient between dairy intake and SGA was observed. Conclusions An inadequate intake of dairy products is associated with a higher risk of SGA. Our results suggest a possible causal relation between dairy intake during pregnancy and the weight of the newborn, although we cannot discard residual confounding. These results should be further supported by properly designed studies. PMID:26971269
Plasma alkylresorcinois, biomarkers of whole-grain intake, are related to lower BMI in older adults
Technology Transfer Automated Retrieval System (TEKTRAN)
Alkylresorcinols (AR) are phenolic lipids found in the bran fraction of whole-grain wheat, rye, and barley. In intervention studies, plasma AR concentration increased in response to greater intakes of whole grain, wheat, and rye. This study examined the cross-sectional associations between plasma AR...
Are Reductions in Population Sodium Intake Achievable?
Levings, Jessica L.; Cogswell, Mary E.; Gunn, Janelle Peralez
2014-01-01
The vast majority of Americans consume too much sodium, primarily from packaged and restaurant foods. The evidence linking sodium intake with direct health outcomes indicates a positive relationship between higher levels of sodium intake and cardiovascular disease risk, consistent with the relationship between sodium intake and blood pressure. Despite communication and educational efforts focused on lowering sodium intake over the last three decades data suggest average US sodium intake has remained remarkably elevated, leading some to argue that current sodium guidelines are unattainable. The IOM in 2010 recommended gradual reductions in the sodium content of packaged and restaurant foods as a primary strategy to reduce US sodium intake, and research since that time suggests gradual, downward shifts in mean population sodium intake are achievable and can move the population toward current sodium intake guidelines. The current paper reviews recent evidence indicating: (1) significant reductions in mean population sodium intake can be achieved with gradual sodium reduction in the food supply, (2) gradual sodium reduction in certain cases can be achieved without a noticeable change in taste or consumption of specific products, and (3) lowering mean population sodium intake can move us toward meeting the current individual guidelines for sodium intake. PMID:25325254
(Carbon isotope fractionation inplants)
O'Leary, M.H.
1990-01-01
The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.