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

Siranosian, Antranik Antonio; Schembri, Philip Edward; Luscher, Darby Jon

The Los Alamos National Laboratory's Weapon Systems Engineering division's Advanced Engineering Analysis group employs material constitutive models of composites for use in simulations of components and assemblies of interest. Experimental characterization, modeling and prediction of the macro-scale (i.e. continuum) behaviors of these composite materials is generally difficult because they exhibit nonlinear behaviors on the meso- (e.g. micro-) and macro-scales. Furthermore, it can be difficult to measure and model the mechanical responses of the individual constituents and constituent interactions in the composites of interest. Current efforts to model such composite materials rely on semi-empirical models in which meso-scale properties are inferredmore » from continuum level testing and modeling. The proposed approach involves removing the difficulties of interrogating and characterizing micro-scale behaviors by scaling-up the problem to work with macro-scale composites, with the intention of developing testing and modeling capabilities that will be applicable to the mesoscale. This approach assumes that the physical mechanisms governing the responses of the composites on the meso-scale are reproducible on the macro-scale. Working on the macro-scale simplifies the quantification of composite constituents and constituent interactions so that efforts can be focused on developing material models and the testing techniques needed for calibration and validation. Other benefits to working with macro-scale composites include the ability to engineer and manufacture—potentially using additive manufacturing techniques—composites that will support the application of advanced measurement techniques such as digital volume correlation and three-dimensional computed tomography imaging, which would aid in observing and quantifying complex behaviors that are exhibited in the macro-scale composites of interest. Ultimately, the goal of this new approach is to develop a meso-scale composite modeling framework, applicable to many composite materials, and the corresponding macroscale testing and test data interrogation techniques to support model calibration.« less

A polynomial-chaos-expansion-based building block approach for stochastic analysis of photonic circuits

NASA Astrophysics Data System (ADS)

Waqas, Abi; Melati, Daniele; Manfredi, Paolo; Grassi, Flavia; Melloni, Andrea

2018-02-01

The Building Block (BB) approach has recently emerged in photonic as a suitable strategy for the analysis and design of complex circuits. Each BB can be foundry related and contains a mathematical macro-model of its functionality. As well known, statistical variations in fabrication processes can have a strong effect on their functionality and ultimately affect the yield. In order to predict the statistical behavior of the circuit, proper analysis of the uncertainties effects is crucial. This paper presents a method to build a novel class of Stochastic Process Design Kits for the analysis of photonic circuits. The proposed design kits directly store the information on the stochastic behavior of each building block in the form of a generalized-polynomial-chaos-based augmented macro-model obtained by properly exploiting stochastic collocation and Galerkin methods. Using this approach, we demonstrate that the augmented macro-models of the BBs can be calculated once and stored in a BB (foundry dependent) library and then used for the analysis of any desired circuit. The main advantage of this approach, shown here for the first time in photonics, is that the stochastic moments of an arbitrary photonic circuit can be evaluated by a single simulation only, without the need for repeated simulations. The accuracy and the significant speed-up with respect to the classical Monte Carlo analysis are verified by means of classical photonic circuit example with multiple uncertain variables.

CONTINUOUS-ENERGY MONTE CARLO METHODS FOR CALCULATING GENERALIZED RESPONSE SENSITIVITIES USING TSUNAMI-3D

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

Perfetti, Christopher M; Rearden, Bradley T

2014-01-01

This work introduces a new approach for calculating sensitivity coefficients for generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The approach presented in this paper, known as the GEAR-MC method, allows for the calculation of generalized sensitivity coefficients for multiple responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here, and proof of principle is demonstrated by using the GEAR-MC method to calculate sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications.

Social Alienation in Schizophrenia Patients: Association with Insula Responsiveness to Facial Expressions of Disgust

PubMed Central

Lindner, Christian; Dannlowski, Udo; Walhöfer, Kirsten; Rödiger, Maike; Maisch, Birgit; Bauer, Jochen; Ohrmann, Patricia; Lencer, Rebekka; Zwitserlood, Pienie; Kersting, Anette; Heindel, Walter; Arolt, Volker

2014-01-01

Introduction Among the functional neuroimaging studies on emotional face processing in schizophrenia, few have used paradigms with facial expressions of disgust. In this study, we investigated whether schizophrenia patients show less insula activation to macro-expressions (overt, clearly visible expressions) and micro-expressions (covert, very brief expressions) of disgust than healthy controls. Furthermore, departing from the assumption that disgust faces signal social rejection, we examined whether perceptual sensitivity to disgust is related to social alienation in patients and controls. We hypothesized that high insula responsiveness to facial disgust predicts social alienation. Methods We used functional magnetic resonance imaging to measure insula activation in 36 schizophrenia patients and 40 healthy controls. During scanning, subjects passively viewed covert and overt presentations of disgust and neutral faces. To measure social alienation, a social loneliness scale and an agreeableness scale were administered. Results Schizophrenia patients exhibited reduced insula activation in response to covert facial expressions of disgust. With respect to macro-expressions of disgust, no between-group differences emerged. In patients, insula responsiveness to covert faces of disgust was positively correlated with social loneliness. Furthermore, patients' insula responsiveness to covert and overt faces of disgust was negatively correlated with agreeableness. In controls, insula responsiveness to covert expressions of disgust correlated negatively with agreeableness. Discussion Schizophrenia patients show reduced insula responsiveness to micro-expressions but not macro-expressions of disgust compared to healthy controls. In patients, low agreeableness was associated with stronger insula response to micro- and macro-expressions of disgust. Patients with a strong tendency to feel uncomfortable with social interactions appear to be characterized by a high sensitivity for facial expression signaling social rejection. Given the associations of insula responsiveness to covert disgust expression with low agreeableness in healthy individuals, insula responsiveness to expressions of disgust might be in general a neural marker of the personality trait of agreeableness. PMID:24465469

Social alienation in schizophrenia patients: association with insula responsiveness to facial expressions of disgust.

PubMed

Lindner, Christian; Dannlowski, Udo; Walhöfer, Kirsten; Rödiger, Maike; Maisch, Birgit; Bauer, Jochen; Ohrmann, Patricia; Lencer, Rebekka; Zwitserlood, Pienie; Kersting, Anette; Heindel, Walter; Arolt, Volker; Kugel, Harald; Suslow, Thomas

2014-01-01

Among the functional neuroimaging studies on emotional face processing in schizophrenia, few have used paradigms with facial expressions of disgust. In this study, we investigated whether schizophrenia patients show less insula activation to macro-expressions (overt, clearly visible expressions) and micro-expressions (covert, very brief expressions) of disgust than healthy controls. Furthermore, departing from the assumption that disgust faces signal social rejection, we examined whether perceptual sensitivity to disgust is related to social alienation in patients and controls. We hypothesized that high insula responsiveness to facial disgust predicts social alienation. We used functional magnetic resonance imaging to measure insula activation in 36 schizophrenia patients and 40 healthy controls. During scanning, subjects passively viewed covert and overt presentations of disgust and neutral faces. To measure social alienation, a social loneliness scale and an agreeableness scale were administered. Schizophrenia patients exhibited reduced insula activation in response to covert facial expressions of disgust. With respect to macro-expressions of disgust, no between-group differences emerged. In patients, insula responsiveness to covert faces of disgust was positively correlated with social loneliness. Furthermore, patients' insula responsiveness to covert and overt faces of disgust was negatively correlated with agreeableness. In controls, insula responsiveness to covert expressions of disgust correlated negatively with agreeableness. Schizophrenia patients show reduced insula responsiveness to micro-expressions but not macro-expressions of disgust compared to healthy controls. In patients, low agreeableness was associated with stronger insula response to micro- and macro-expressions of disgust. Patients with a strong tendency to feel uncomfortable with social interactions appear to be characterized by a high sensitivity for facial expression signaling social rejection. Given the associations of insula responsiveness to covert disgust expression with low agreeableness in healthy individuals, insula responsiveness to expressions of disgust might be in general a neural marker of the personality trait of agreeableness.

Healthy public policy in poor countries: tackling macro-economic policies.

PubMed

Mohindra, K S

2007-06-01

Large segments of the population in poor countries continue to suffer from a high level of unmet health needs, requiring macro-level, broad-based interventions. Healthy public policy, a key health promotion strategy, aims to put health on the agenda of policy makers across sectors and levels of government. Macro-economic policy in developing countries has thus far not adequately captured the attention of health promotion researchers. This paper argues that healthy public policy should not only be an objective in rich countries, but also in poor countries. This paper takes up this issue by reviewing the main macro-economic aid programs offered by international financial institutions as a response to economic crises and unmanageable debt burdens. Although health promotion researchers were largely absent during a key debate on structural adjustment programs and health during the 1980s and 1990s, the international macro-economic policy tool currently in play offers a new opportunity to participate in assessing these policies, ensuring new forms of macro-economic policy interventions do not simply reproduce patterns of (neoliberal) economics-dominated development policy.

Investigating the interplay between substrate stiffness and ligand chemistry in directing mesenchymal stem cell differentiation within 3D macro-porous substrates.

PubMed

Haugh, Matthew G; Vaughan, Ted J; Madl, Christopher M; Raftery, Rosanne M; McNamara, Laoise M; O'Brien, Fergal J; Heilshorn, Sarah C

2018-07-01

Dimensionality can have a profound impact on stiffness-mediated differentiation of mesenchymal stem cells (MSCs). However, while we have begun to understand cellular response when encapsulated within 3D substrates, the behavior of cells within macro-porous substrates is relatively underexplored. The goal of this study was to determine the influence of macro-porous topographies on stiffness-mediated differentiation of MSCs. We developed macro-porous recombinant elastin-like protein (ELP) substrates that allow independent control of mechanical properties and ligand chemistry. We then used computational modeling to probe the impact of pore topography on the mechanical stimulus that cells are exposed to within these substrates, and finally we investigated stiffness induced biases towards adipogenic and osteogenic differentiation of MSCs within macro-porous substrates. Computational modeling revealed that there is significant heterogeneity in the mechanical stimuli that cells are exposed to within porous substrates and that this heterogeneity is predominantly due to the wide range of possible cellular orientations within the pores. Surprisingly, MSCs grown within 3D porous substrates respond to increasing substrate stiffness by up-regulating both osteogenesis and adipogenesis. These results demonstrate that within porous substrates the behavior of MSCs diverges from previously observed responses to substrate stiffness, emphasizing the importance of topography as a determinant of cellular behavior. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic Modeling of New Technology Succession: Projecting the Impact of Macro Events and Micro Behaviors On Software Market Cycles

NASA Astrophysics Data System (ADS)

Mertz, Sharon A.; Groothuis, Adam; Fellman, Philip Vos

The subject of technology succession and new technology adoption in a generalized sense has been addressed by numerous authors for over one hundred years. Models which accommodate macro-level events as well as micro-level actions are needed to gain insight to future market outcomes. In the ICT industry, macro-level factors affecting technology adoption include global events and shocks, economic factors, and global regulatory trends. Micro-level elements involve individual agent actions and interactions, such as the behaviors of buyers and suppliers in reaction to each other, and to macro events. Projecting technology adoption and software market composition and growth requires evaluating a special set of technology characteristics, buyer behaviors, and supplier issues and responses which make this effort particularly challenging.

Numerical integration of detector response functions via Monte Carlo simulations

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

Kelly, Keegan John; O'Donnell, John M.; Gomez, Jaime A.

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated inmore » this way can be used to create Monte Carlo simulation output spectra a factor of ~1000× faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. Here, this method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.« less

Numerical integration of detector response functions via Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Kelly, K. J.; O'Donnell, J. M.; Gomez, J. A.; Taddeucci, T. N.; Devlin, M.; Haight, R. C.; White, M. C.; Mosby, S. M.; Neudecker, D.; Buckner, M. Q.; Wu, C. Y.; Lee, H. Y.

2017-09-01

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated in this way can be used to create Monte Carlo simulation output spectra a factor of ∼ 1000 × faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. This method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.

Numerical integration of detector response functions via Monte Carlo simulations

DOE PAGES

Kelly, Keegan John; O'Donnell, John M.; Gomez, Jaime A.; ...

2017-06-13

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated inmore » this way can be used to create Monte Carlo simulation output spectra a factor of ~1000× faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. Here, this method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.« less

Generating variable and random schedules of reinforcement using Microsoft Excel macros.

PubMed

Bancroft, Stacie L; Bourret, Jason C

2008-01-01

Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values.

Multi-response permutation procedure as an alternative to the analysis of variance: an SPSS implementation.

PubMed

Cai, Li

2006-02-01

A permutation test typically requires fewer assumptions than does a comparable parametric counterpart. The multi-response permutation procedure (MRPP) is a class of multivariate permutation tests of group difference useful for the analysis of experimental data. However, psychologists seldom make use of the MRPP in data analysis, in part because the MRPP is not implemented in popular statistical packages that psychologists use. A set of SPSS macros implementing the MRPP test is provided in this article. The use of the macros is illustrated by analyzing example data sets.

Statistical Evaluation and Improvement of Methods for Combining Random and Harmonic Loads

NASA Technical Reports Server (NTRS)

Brown, A. M.; McGhee, D. S.

2003-01-01

Structures in many environments experience both random and harmonic excitation. A variety of closed-form techniques has been used in the aerospace industry to combine the loads resulting from the two sources. The resulting combined loads are then used to design for both yield/ultimate strength and high- cycle fatigue capability. This Technical Publication examines the cumulative distribution percentiles obtained using each method by integrating the joint probability density function of the sine and random components. A new Microsoft Excel spreadsheet macro that links with the software program Mathematica to calculate the combined value corresponding to any desired percentile is then presented along with a curve tit to this value. Another Excel macro that calculates the combination using Monte Carlo simulation is shown. Unlike the traditional techniques. these methods quantify the calculated load value with a consistent percentile. Using either of the presented methods can be extremely valuable in probabilistic design, which requires a statistical characterization of the loading. Additionally, since the CDF at high probability levels is very flat, the design value is extremely sensitive to the predetermined percentile; therefore, applying the new techniques can substantially lower the design loading without losing any of the identified structural reliability.

Statistical Comparison and Improvement of Methods for Combining Random and Harmonic Loads

NASA Technical Reports Server (NTRS)

Brown, Andrew M.; McGhee, David S.

2004-01-01

Structures in many environments experience both random and harmonic excitation. A variety of closed-form techniques has been used in the aerospace industry to combine the loads resulting from the two sources. The resulting combined loads are then used to design for both yield ultimate strength and high cycle fatigue capability. This paper examines the cumulative distribution function (CDF) percentiles obtained using each method by integrating the joint probability density function of the sine and random components. A new Microsoft Excel spreadsheet macro that links with the software program Mathematics is then used to calculate the combined value corresponding to any desired percentile along with a curve fit to this value. Another Excel macro is used to calculate the combination using a Monte Carlo simulation. Unlike the traditional techniques, these methods quantify the calculated load value with a Consistent percentile. Using either of the presented methods can be extremely valuable in probabilistic design, which requires a statistical characterization of the loading. Also, since the CDF at high probability levels is very flat, the design value is extremely sensitive to the predetermined percentile; therefore, applying the new techniques can lower the design loading substantially without losing any of the identified structural reliability.

Linking a one-dimensional pesticide fate model to a three-dimensional groundwater model to simulate pollution risks of shallow and deep groundwater underlying fractured till.

PubMed

Stenemo, Fredrik; Jørgensen, Peter R; Jarvis, Nicholas

2005-09-01

The one-dimensional pesticide fate model MACRO was loose-linked to the three-dimensional discrete fracture/matrix diffusion model FRAC3DVS to describe transport of the pesticide mecoprop in a fractured moraine till and local sand aquifer (5-5.5 m depth) overlying a regional limestone aquifer (16 m depth) at Havdrup, Denmark. Alternative approaches to describe the upper boundary in the groundwater model were examined. Field-scale simulations were run to compare a uniform upper boundary condition with a spatially variable upper boundary derived from Monte-Carlo simulations with MACRO. Plot-scale simulations were run to investigate the influence of the temporal resolution of the upper boundary conditions for fluxes in the groundwater model and the effects of different assumptions concerning the macropore/fracture connectivity between the two models. The influence of within-field variability of leaching on simulated mecoprop concentrations in the local aquifer was relatively small. A fully transient simulation with FRAC3DVS gave 20 times larger leaching to the regional aquifer compared to the case with steady-state water flow, assuming full connectivity with respect to macropores/fractures across the boundary between the two models. For fully transient simulations 'disconnecting' the macropores/fractures at the interface between the two models reduced leaching by a factor 24. A fully connected, transient simulation with FRAC3DVS, with spatially uniform upper boundary fluxes derived from a MACRO simulation with 'effective' parameters is therefore recommended for assessing leaching risks to the regional aquifer, at this, and similar sites.

Joint reconstruction of dynamic PET activity and kinetic parametric images using total variation constrained dictionary sparse coding

NASA Astrophysics Data System (ADS)

Yu, Haiqing; Chen, Shuhang; Chen, Yunmei; Liu, Huafeng

2017-05-01

Dynamic positron emission tomography (PET) is capable of providing both spatial and temporal information of radio tracers in vivo. In this paper, we present a novel joint estimation framework to reconstruct temporal sequences of dynamic PET images and the coefficients characterizing the system impulse response function, from which the associated parametric images of the system macro parameters for tracer kinetics can be estimated. The proposed algorithm, which combines statistical data measurement and tracer kinetic models, integrates a dictionary sparse coding (DSC) into a total variational minimization based algorithm for simultaneous reconstruction of the activity distribution and parametric map from measured emission sinograms. DSC, based on the compartmental theory, provides biologically meaningful regularization, and total variation regularization is incorporated to provide edge-preserving guidance. We rely on techniques from minimization algorithms (the alternating direction method of multipliers) to first generate the estimated activity distributions with sub-optimal kinetic parameter estimates, and then recover the parametric maps given these activity estimates. These coupled iterative steps are repeated as necessary until convergence. Experiments with synthetic, Monte Carlo generated data, and real patient data have been conducted, and the results are very promising.

Economic value of big game habitat production from natural and prescribed fire

Treesearch

Armando Gonzalez-Caban; John B. Loomis; Dana Griffin; Elen Wu; Daniel McCollum; Jane McKeever; Diane Freeman

2003-01-01

A macro time-series model and a micro GIS model were used to estimate a production function relating deer harvest response to prescribed fire, holding constant other environmental variables. The macro time-series model showed a marginal increase in deer harvested of 33 for an increase of 1,100 acres of prescribed burn. The marginal deer increase for the micro GIS model...

Load-Unload Response Ratio (LURR), Accelerating Moment/Energy Release (AM/ER) and State Vector Saltation as Precursors to Failure of Rock Specimens

NASA Astrophysics Data System (ADS)

Yin, Xiang-Chu; Yu, Huai-Zhong; Kukshenko, Victor; Xu, Zhao-Yong; Wu, Zhishen; Li, Min; Peng, Keyin; Elizarov, Surgey; Li, Qi

2004-12-01

In order to verify some precursors such as LURR (Load/Unload Response Ratio) and AER (Accelerating Energy Release) before large earthquakes or macro-fracture in heterogeneous brittle media, four acoustic emission experiments involving large rock specimens under tri-axial stress, have been conducted. The specimens were loaded in two ways: monotonous or cycling. The experimental results confirm that LURR and AER are precursors of macro-fracture in brittle media. A new measure called the state vector has been proposed to describe the damage evolution of loaded rock specimens.

Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

PubMed Central

Bancroft, Stacie L; Bourret, Jason C

2008-01-01

Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values. PMID:18595286

Bridging the Gap Between Micro and Macro Practice to Address Homelessness in the U.S.-Mexico Border Region: Implications for Practitioners and Community Stakeholders

PubMed Central

Moya, Eva M.; Chavez-Baray, Silvia Maria; Martinez, Omar; Mattera, Brian; Adcox, Courtney

2018-01-01

Research and scholarship efforts continue to promote the integration of micro and macro practice in social work practice and education. Despite this, scholarship has documented persistent challenges in the fluid integration between the domains of micro-level service provision and macro-level social change efforts in practice and academic programs. This paper outlines a successful bridge between the micro-macro divide in the form of community-engaged practice to address homelessness and social work education in the U.S.-Mexico border region. MSW students enrolled in a macro-level course at the University of Texas at El Paso’s College of Health Sciences successfully partnered with the Opportunity Center for the Homeless, a grassroots community-based organization serving individuals experiencing homelessness. The narrative describes how students were effectively able to apply both micro- and macro-level skills learned in the classroom to an experiential learning environment while providing much-needed assistance to an underfunded community-based organization. A set of challenges and recommendations are also discussed. Research initiatives are needed to evaluate and test clinical and community work initiatives, including the use of photovoice methodology to address homelessness, while being responsive to community needs and challenges. PMID:29809204

Bridging the Gap Between Micro and Macro Practice to Address Homelessness in the U.S.-Mexico Border Region: Implications for Practitioners and Community Stakeholders.

PubMed

Moya, Eva M; Chavez-Baray, Silvia Maria; Martinez, Omar; Mattera, Brian; Adcox, Courtney

2018-01-01

Research and scholarship efforts continue to promote the integration of micro and macro practice in social work practice and education. Despite this, scholarship has documented persistent challenges in the fluid integration between the domains of micro-level service provision and macro-level social change efforts in practice and academic programs. This paper outlines a successful bridge between the micro-macro divide in the form of community-engaged practice to address homelessness and social work education in the U.S.-Mexico border region. MSW students enrolled in a macro-level course at the University of Texas at El Paso's College of Health Sciences successfully partnered with the Opportunity Center for the Homeless, a grassroots community-based organization serving individuals experiencing homelessness. The narrative describes how students were effectively able to apply both micro- and macro-level skills learned in the classroom to an experiential learning environment while providing much-needed assistance to an underfunded community-based organization. A set of challenges and recommendations are also discussed. Research initiatives are needed to evaluate and test clinical and community work initiatives, including the use of photovoice methodology to address homelessness, while being responsive to community needs and challenges.

Controls on atrazine leaching through a soil-unsaturated fractured limestone sequence at Brévilles, France.

PubMed

Roulier, Stéphanie; Baran, Nicole; Mouvet, Christophe; Stenemo, Fredrik; Morvan, Xavier; Albrechtsen, Hans-Jørgen; Clausen, Liselotte; Jarvis, Nicholas

2006-03-01

The objective of this study was to identify the main controls on atrazine leaching through luvisols and calcisols overlying fissured limestone using the dual-permeability model MACRO. The model parameterisation was based on a combination of direct measurements (e.g. hydraulic properties, adsorption and degradation), literature data and calibration against bromide leaching experiments in field plots. A Monte Carlo sensitivity analysis was carried out for a typical application pattern, considering two different depths of unsaturated limestone (15 and 30 m). MACRO calibrations to the field experiments demonstrated the occurrence of strong macropore flow in the luvisol, while transport in the calcisol could be described by the advection-dispersion equation. MACRO simulations of tritium and atrazine leaching qualitatively matched tritium concentration profiles measured in the limestone and atrazine concentrations measured in piezometers and in aquifer discharge via a spring. The sensitivity analysis suggested that the thickness of the limestone, as well as the transport properties and processes occurring in the unsaturated rock (e.g. matrix vs. fissure flow) will have little significant long-term effect on atrazine leaching, mainly because degradation is very slow in the limestone. No mineralization of atrazine was detected in one-year incubations and a mean half-life of 10 years was assumed in the simulations. Instead, processes occurring in the soil exerted the main control on predicted atrazine leaching, especially variations in the degradation rate and the strength of sorption and macropore flow. However, fissure flow in unsaturated rock is expected to exert a much more significant control on groundwater contamination for compounds that degrade more readily in the deep vadose zone.

The use of Monte Carlo simulations for accurate dose determination with thermoluminescence dosemeters in radiation therapy beams.

PubMed

Mobit, P

2002-01-01

The energy responses of LiF-TLDs irradiated in megavoltage electron and photon beams have been determined experimentally by many investigators over the past 35 years but the results vary considerably. General cavity theory has been used to model some of the experimental findings but the predictions of these cavity theories differ from each other and from measurements by more than 13%. Recently, two groups or investigators using Monte Carlo simulations and careful experimental techniques showed that the energy response of 1 mm or 2 mm thick LiF-TLD irradiated by megavoltage photon and electron beams is not more than 5% less than unity for low-Z phantom materials like water or Perspex. However, when the depth of irradiation is significantly different from dmax and the TLD size is more than 5 mm, then the energy response is up to 12% less than unity for incident electron beams. Monte Carlo simulations of some of the experiments reported in the literature showed that some of the contradictory experimental results are reproducible with Monte Carlo simulations. Monte Carlo simulations show that the energy response of LiF-TLDs depends on the size of detector used in electron beams, the depth of irradiation and the incident electron energy. Other differences can be attributed to absolute dose determination and precision of the TL technique. Monte Carlo simulations have also been used to evaluate some of the published general cavity theories. The results show that some of the parameters used to evaluate Burlin's general cavity theory are wrong by factor of 3. Despite this, the estimation of the energy response for most clinical situations using Burlin's cavity equation agrees with Monte Carlo simulations within 1%.

On Fitting a Multivariate Two-Part Latent Growth Model

PubMed Central

Xu, Shu; Blozis, Shelley A.; Vandewater, Elizabeth A.

2017-01-01

A 2-part latent growth model can be used to analyze semicontinuous data to simultaneously study change in the probability that an individual engages in a behavior, and if engaged, change in the behavior. This article uses a Monte Carlo (MC) integration algorithm to study the interrelationships between the growth factors of 2 variables measured longitudinally where each variable can follow a 2-part latent growth model. A SAS macro implementing Mplus is developed to estimate the model to take into account the sampling uncertainty of this simulation-based computational approach. A sample of time-use data is used to show how maximum likelihood estimates can be obtained using a rectangular numerical integration method and an MC integration method. PMID:29333054

A multiscale method for modeling high-aspect-ratio micro/nano flows

NASA Astrophysics Data System (ADS)

Lockerby, Duncan; Borg, Matthew; Reese, Jason

2012-11-01

In this paper we present a new multiscale scheme for simulating micro/nano flows of high aspect ratio in the flow direction, e.g. within long ducts, tubes, or channels, of varying section. The scheme consists of applying a simple hydrodynamic description over the entire domain, and allocating micro sub-domains in very small ``slices'' of the channel. Every micro element is a molecular dynamics simulation (or other appropriate model, e.g., a direct simulation Monte Carlo method for micro-channel gas flows) over the local height of the channel/tube. The number of micro elements as well as their streamwise position is chosen to resolve the geometrical features of the macro channel. While there is no direct communication between individual micro elements, coupling occurs via an iterative imposition of mass and momentum-flux conservation on the macro scale. The greater the streamwise scale of the geometry, the more significant is the computational speed-up when compared to a full MD simulation. We test our new multiscale method on the case of a converging/diverging nanochannel conveying a simple Lennard-Jones liquid. We validate the results from our simulations by comparing them to a full MD simulation of the same test case. Supported by EPSRC Programme Grant, EP/I011927/1.

Recovery of Graded Response Model Parameters: A Comparison of Marginal Maximum Likelihood and Markov Chain Monte Carlo Estimation

ERIC Educational Resources Information Center

Kieftenbeld, Vincent; Natesan, Prathiba

2012-01-01

Markov chain Monte Carlo (MCMC) methods enable a fully Bayesian approach to parameter estimation of item response models. In this simulation study, the authors compared the recovery of graded response model parameters using marginal maximum likelihood (MML) and Gibbs sampling (MCMC) under various latent trait distributions, test lengths, and…

Cell cycle, oncogenic and tumor suppressor pathways regulate numerous long and macro non-protein-coding RNAs

PubMed Central

2014-01-01

Background The genome is pervasively transcribed but most transcripts do not code for proteins, constituting non-protein-coding RNAs. Despite increasing numbers of functional reports of individual long non-coding RNAs (lncRNAs), assessing the extent of functionality among the non-coding transcriptional output of mammalian cells remains intricate. In the protein-coding world, transcripts differentially expressed in the context of processes essential for the survival of multicellular organisms have been instrumental in the discovery of functionally relevant proteins and their deregulation is frequently associated with diseases. We therefore systematically identified lncRNAs expressed differentially in response to oncologically relevant processes and cell-cycle, p53 and STAT3 pathways, using tiling arrays. Results We found that up to 80% of the pathway-triggered transcriptional responses are non-coding. Among these we identified very large macroRNAs with pathway-specific expression patterns and demonstrated that these are likely continuous transcripts. MacroRNAs contain elements conserved in mammals and sauropsids, which in part exhibit conserved RNA secondary structure. Comparing evolutionary rates of a macroRNA to adjacent protein-coding genes suggests a local action of the transcript. Finally, in different grades of astrocytoma, a tumor disease unrelated to the initially used cell lines, macroRNAs are differentially expressed. Conclusions It has been shown previously that the majority of expressed non-ribosomal transcripts are non-coding. We now conclude that differential expression triggered by signaling pathways gives rise to a similar abundance of non-coding content. It is thus unlikely that the prevalence of non-coding transcripts in the cell is a trivial consequence of leaky or random transcription events. PMID:24594072

Response Matrix Monte Carlo for electron transport

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

Ballinger, C.T.; Nielsen, D.E. Jr.; Rathkopf, J.A.

1990-11-01

A Response Matrix Monte Carol (RMMC) method has been developed for solving electron transport problems. This method was born of the need to have a reliable, computationally efficient transport method for low energy electrons (below a few hundred keV) in all materials. Today, condensed history methods are used which reduce the computation time by modeling the combined effect of many collisions but fail at low energy because of the assumptions required to characterize the electron scattering. Analog Monte Carlo simulations are prohibitively expensive since electrons undergo coulombic scattering with little state change after a collision. The RMMC method attempts tomore » combine the accuracy of an analog Monte Carlo simulation with the speed of the condensed history methods. The combined effect of many collisions is modeled, like condensed history, except it is precalculated via an analog Monte Carol simulation. This avoids the scattering kernel assumptions associated with condensed history methods. Results show good agreement between the RMMC method and analog Monte Carlo. 11 refs., 7 figs., 1 tabs.« less

Preparation of thermo-responsive graft copolymer by using a novel macro-RAFT agent and its application for drug delivery.

PubMed

Song, Cunfeng; Yu, Shirong; Liu, Cheng; Deng, Yuanming; Xu, Yiting; Chen, Xiaoling; Dai, Lizong

2016-05-01

A methodology to prepare thermo-responsive graft copolymer by using a novel macro-RAFT agent was proposed. The macro-RAFT agent with pendant dithioester (ZC(S)SR) was facilely prepared via the combination of RAFT polymerization and esterification reaction. By means of ZC(S)SR-initiated RAFT polymerization, the thermo-responsive graft copolymer consisting of poly(methyl methacrylate-co-hydroxylethyl methacrylate) (P(MMA-co-HEMA)) backbone and hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) side chains was constructed through the "grafting from" approach. The chemical compositions and molecular weight distributions of the synthesized polymers were respectively characterized by (1)H nuclear magnetic resonance ((1)H NMR) and gel permeation chromatography (GPC). Self-assembly behavior of the amphiphilic graft copolymers (P(MMA-co-HEMA)-g-PNIPAAm) was studied by transmission electron microscopy (TEM), dynamic light scattering (DLS) and spectrofluorimeter. The critical micelle concentration (CMC) value was 0.052 mg mL(-1). These micelles have thermo-responsibility and a low critical solution temperature (LCST) of 33.5°C. Further investigation indicated that the guest molecule release property of these micelles, which can be well described by a first-order kinetic model, was significantly affected by temperature. Besides, the micelles exhibited excellent biocompatibility and cellular uptake property. Hence, these micelles are considered to have potential application in controlled drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

A hybrid method with deviational particles for spatial inhomogeneous plasma

NASA Astrophysics Data System (ADS)

Yan, Bokai

2016-03-01

In this work we propose a Hybrid method with Deviational Particles (HDP) for a plasma modeled by the inhomogeneous Vlasov-Poisson-Landau system. We split the distribution into a Maxwellian part evolved by a grid based fluid solver and a deviation part simulated by numerical particles. These particles, named deviational particles, could be both positive and negative. We combine the Monte Carlo method proposed in [31], a Particle in Cell method and a Macro-Micro decomposition method [3] to design an efficient hybrid method. Furthermore, coarse particles are employed to accelerate the simulation. A particle resampling technique on both deviational particles and coarse particles is also investigated and improved. This method is applicable in all regimes and significantly more efficient compared to a PIC-DSMC method near the fluid regime.

Probing microstructural information of anisotropic scattering media using rotation-independent polarization parameters.

PubMed

Sun, Minghao; He, Honghui; Zeng, Nan; Du, E; Guo, Yihong; Peng, Cheng; He, Yonghong; Ma, Hui

2014-05-10

Polarization parameters contain rich information on the micro- and macro-structure of scattering media. However, many of these parameters are sensitive to the spatial orientation of anisotropic media, and may not effectively reveal the microstructural information. In this paper, we take polarization images of different textile samples at different azimuth angles. The results demonstrate that the rotation insensitive polarization parameters from rotating linear polarization imaging and Mueller matrix transformation methods can be used to distinguish the characteristic features of different textile samples. Further examinations using both experiments and Monte Carlo simulations reveal that the residue rotation dependence in these polarization parameters is due to the oblique incidence illumination. This study shows that such rotation independent parameters are potentially capable of quantitatively classifying anisotropic samples, such as textiles or biological tissues.

Laser speckle contrast imaging of cerebral autoregulation in rats at a macro- and microcirculation level

NASA Astrophysics Data System (ADS)

Semyachkina-Glushkovskaya, O. V.; Abdurashitov, A. S.; Sindeev, S. S.; Tuchin, V. V.

2016-06-01

Using the method of laser speckle imaging for the simultaneous study of macro- and microcirculation in cerebral vessels of healthy rats, we show that the mechanisms underlying cerebral autoregulation depend on the initial condition of the organism and the sex of individual animals. The pharmacological dose-dependent stimulation of the peripheral arterial pressure increase is not accompanied by the cerebral circulation responses of analogous intensity, but manifests itself as 'compensating' reactions, namely, the redistribution of the blood flow at the level of macro- (in females) and microcirculation (in females and males). The obtained results extend our understanding of the capabilities of laser speckle imaging technique in neurophysiological studies of reserve abilities of cerebral circulation autoregulation under the conditions of hypertensive status formation.

A macro perspective for client-centred practice in curricula: Critique and teaching methods.

PubMed

Fleming-Castaldy, Rita P

2015-07-01

Client-centred practice is often eclipsed by social, economic, and political inequities. Ignoring these realities obstructs clients' goal attainment. The author advocates for the integration of a macro perspective inclusive of participation barriers and supports in occupational therapy curricula and seeks to motivate educators to adopt teaching approaches that develop students' abilities to address the complexities of client-centred practice. This article integrates a critical analysis of the literature on client-centred practice with reflexivity on disability studies and autoethnography. Educational standards require students to learn about the social, economic, and political contexts that impact on client-centred practice and the need for advocacy to enable participation. Theoretical support of a macro perspective for client-centred practice is strongly evident in the literature. Information on methods for teaching students how to actualize these concepts in practice is scant. Thus, strategies to inform the integration of a macro perspective into curricula and concrete activities to develop students' competencies for empowered client-centred practice are required. Educators have an ethical responsibility to critique their pedagogy to determine whether they are adequately preparing students for client-centred practice. The focus must move from teaching a micro perspective of client-centred practice to a macro perspective that enables occupational justice and empowerment.

Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

NASA Astrophysics Data System (ADS)

Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

2017-02-01

Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25-2 mm), and micro- (0.053-0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics.

Climate change and ocean acidification effects on seagrasses and marine macroalgae.

PubMed

Koch, Marguerite; Bowes, George; Ross, Cliff; Zhang, Xing-Hai

2013-01-01

Although seagrasses and marine macroalgae (macro-autotrophs) play critical ecological roles in reef, lagoon, coastal and open-water ecosystems, their response to ocean acidification (OA) and climate change is not well understood. In this review, we examine marine macro-autotroph biochemistry and physiology relevant to their response to elevated dissolved inorganic carbon [DIC], carbon dioxide [CO2 ], and lower carbonate [CO3 (2-) ] and pH. We also explore the effects of increasing temperature under climate change and the interactions of elevated temperature and [CO2 ]. Finally, recommendations are made for future research based on this synthesis. A literature review of >100 species revealed that marine macro-autotroph photosynthesis is overwhelmingly C3 (≥ 85%) with most species capable of utilizing HCO3 (-) ; however, most are not saturated at current ocean [DIC]. These results, and the presence of CO2 -only users, lead us to conclude that photosynthetic and growth rates of marine macro-autotrophs are likely to increase under elevated [CO2 ] similar to terrestrial C3 species. In the tropics, many species live close to their thermal limits and will have to up-regulate stress-response systems to tolerate sublethal temperature exposures with climate change, whereas elevated [CO2 ] effects on thermal acclimation are unknown. Fundamental linkages between elevated [CO2 ] and temperature on photorespiration, enzyme systems, carbohydrate production, and calcification dictate the need to consider these two parameters simultaneously. Relevant to calcifiers, elevated [CO2 ] lowers net calcification and this effect is amplified by high temperature. Although the mechanisms are not clear, OA likely disrupts diffusion and transport systems of H(+) and DIC. These fluxes control micro-environments that promote calcification over dissolution and may be more important than CaCO3 mineralogy in predicting macroalgal responses to OA. Calcareous macroalgae are highly vulnerable to OA, and it is likely that fleshy macroalgae will dominate in a higher CO2 ocean; therefore, it is critical to elucidate the research gaps identified in this review. © 2012 Blackwell Publishing Ltd.

Technique for writing of fiber Bragg gratings over or near preliminary formed macro-structure defects in silica optical fibers

NASA Astrophysics Data System (ADS)

Evtushenko, Alexander S.; Faskhutdinov, Lenar M.; Kafarova, Anastasia M.; Kazakov, Vadim S.; Kuznetzov, Artem A.; Minaeva, Alina Yu.; Sevruk, Nikita L.; Nureev, Ilnur I.; Vasilets, Alexander A.; Andreev, Vladimir A.; Morozov, Oleg G.; Burdin, Vladimir A.; Bourdine, Anton V.

2017-04-01

This work presents method for performing precision macro-structure defects "tapers" and "up-tapers" written in conventional silica telecommunication multimode optical fibers by commercially available field fusion splicer with modified software settings and following writing fiber Bragg gratings over or near them. We developed technique for macrodefect geometry parameters estimation via analysis of photo-image performed after defect writing and displayed on fusion splicer screen. Some research results of defect geometry dependence on fusion current and fusion time values re-set in splicer program are represented that provided ability to choose their "the best" combination. Also experimental statistical researches concerned with "taper" and "up-taper" diameter stability as well as their insertion loss values during their writing under fixed corrected splicer program parameters were performed. We developed technique for FBG writing over or near macro-structure defect. Some results of spectral response measurements produced for short-length samples of multimode optical fiber with fiber Bragg gratings written over and near macro-defects prepared by using proposed technique are presented.

A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications

DOE PAGES

Choi, Sooyoung; Kong, Chidong; Lee, Deokjung; ...

2015-03-09

A new methodology has been developed recently to treat resonance self-shielding in systems for which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. The theoretical development adopts equivalence theory in both micro- and macro-level heterogeneities to provide approximate analytical expressions for the shielded cross sections, which may be interpolated from a table of resonance integrals or Bondarenko factors using a modified background cross section as the interpolation parameter. This paper describes the first implementation of the theoretical equations in a reactor analysis code. In order to reduce discrepancies caused bymore » use of the rational approximation for collision probabilities in the original derivation, a new formulation for a doubly heterogeneous Bell factor is developed in this paper to improve the accuracy of doubly heterogeneous expressions. This methodology is applied to a wide range of pin cell and assembly test problems with varying geometry parameters, material compositions, and temperatures, and the results are compared with continuous-energy Monte Carlo simulations to establish the accuracy and range of applicability of the new approach. It is shown that the new doubly heterogeneous self-shielding method including the Bell factor correction gives good agreement with reference Monte Carlo results.« less

Clinimetrics and clinical psychometrics: macro- and micro-analysis.

PubMed

Tomba, Elena; Bech, Per

2012-01-01

Clinimetrics was introduced three decades ago to specify the domain of clinical markers in clinical medicine (indexes or rating scales). In this perspective, clinical validity is the platform for selecting the various indexes or rating scales (macro-analysis). Psychometric validation of these indexes or rating scales is the measuring aspect (micro-analysis). Clinical judgment analysis by experienced psychiatrists is included in the macro-analysis and the item response theory models are especially preferred in the micro-analysis when using the total score as a sufficient statistic. Clinical assessment tools covering severity of illness scales, prognostic measures, issues of co-morbidity, longitudinal assessments, recovery, stressors, lifestyle, psychological well-being, and illness behavior have been identified. The constructive dialogue in clinimetrics between clinical judgment and psychometric validation procedures is outlined for generating developments of clinical practice in psychiatry. Copyright © 2012 S. Karger AG, Basel.

Multifractal analysis of macro- and microcerebral circulation in rats

NASA Astrophysics Data System (ADS)

Pavlov, Alexey N.; Sindeeva, Olga S.; Sindeev, Sergey S.; Pavlova, Olga N.; Abdurashitov, Arkady S.; Rybalova, Elena V.; Semyachkina-Glushkovskaya, Oxana V.

2016-04-01

Application of noninvasive optical coherent-domain methods and advanced data processing tools such as the wavelet-based multifractal formalism allows revealing effective markers of early stages of functional distortions in the dynamics of cerebral vessels. Based on experiments performed in rats we discuss a possibility to diagnose a hidden stage of the development of intracranial hemorrhage (ICH). We also consider responses of the cerebrovascular dynamics to a pharmacologically induced increase in the peripheral blood pressure. We report distinctions occurring at the levels of macro- and microcerebral circulation.

The effect of micro and macro stressors in the work environment on computer professionals' subjective health status and productive behavior in Japan.

PubMed

Tominaga, Maki; Asakura, Takashi; Akiyama, Tsuyoshi

2007-06-01

To investigate the effect of micro and macro stressors in the work environment on the subjective health status and productive behavior of computer professionals, we conducted a web-based investigation with Japanese IT-related company employees in 53 company unions. The questionnaire consisted of individual attributes, employment characteristics, working hour characteristics, company size and profitability, personal characteristics (i.e., Growth Need Strength), micro and macro stressors scale, and four outcome scales concerning the subjective health status and productive behavior. We obtained 1,049 Japanese IT-related company employees' data (response rate: 66%), and analyzed the data of computer engineers (80%; n=871). The results of hierarchical multiple regressions showed that each full model explained 23% in psychological distress, 20% in cumulative fatigue, 44% in job dissatisfaction, and 35% in intentions to leave, respectively. In micro stressors, "quantitative and qualitative work overload" had the strongest influence on both the subjective health status and intentions to leave. Furthermore, in macro stressors, "career and future ambiguity" was the most important predictor of the subjective health status, and "insufficient evaluation systems" and "poor supervisor's support" were important predictors of productive behavior as well. These findings suggest that improving not only micro stressors but also macro stressors will enhance the subjective health status and increase the productive behavior of computer professionals in Japan.

Response of aquatic macro-invertebrate diversity to environmental factors along the Lower Komati River in Swaziland

NASA Astrophysics Data System (ADS)

Dlamini, Vuyisile; Hoko, Zvikomborero; Murwira, Amon; Magagula, Cebisile

This paper assessed macro-invertebrates diversity as an indicator of aquatic ecosystem health in the Lower Komati River. It also investigated whether this diversity is a function of physico-chemical water quality parameters along an area with major agricultural activities. Bio-assessment of aquatic macro-invertebrates present in the Lower Komati River was carried out at seven sites on the river over 3 months. Water samples were also collected at these sites and analysed for pH, dissolved oxygen, electrical conductivity, turbidity, nitrates, ammonia and ortho-phosphates according to standard methods. It was found out that species diversity along agricultural fields was not significantly different ( p > 0.05) between successive sites. However, nitrate and turbidity among the physico-chemical parameters indicated a significant variation of mean values ( p < 0.05) between sites. With the exception of turbidity, no significant relationship ( p > 0.05) was found between diversity and water quality parameters. Principal Component Analysis also demonstrated the influence of turbidity in the sub-catchments as it was the only parameter that showed a significant loading in all Principal Components. Turbidity seems to be the main parameter influencing aquatic macro-invertebrate diversity in the Lower Komati River at the time of study. The study recommends further studies to determine the seasonal variation of the impact of water quality on macro-invertebrates diversity.

Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

PubMed Central

Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

2017-01-01

Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25–2 mm), and micro- (0.053–0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics. PMID:28211507

Monitoring multi-year macro ocean litter dynamics and backward-tracking simulation of litter origins on a remote island in the South China Sea

NASA Astrophysics Data System (ADS)

Ko, Chia-Ying; Hsin, Yi-Chia; Yu, Teng-Lang; Liu, Kuo-Lieh; Shiah, Fuh-Kwo; Jeng, Ming-Shiou

2018-04-01

Ocean litter has accumulated rapidly and is becoming a major environmental concern, yet quantitative and regular observations and exploration that track litter origins are limited. By implementing monthly sample collections over five years (2012–2016) at Dongsha Island, a remote island in the northern South China Sea (SCS), we assessed macro ocean litter dynamics, identified source countries of individual plastic bottles, and analyzed the origins of the litter by a backward-tracking model simulation considering both the effects of current velocity and windage. The results showed that large amounts of litter, which varied monthly and annually in weight and quantity, reached the island during the study years, and there were spatial differences in accumulation patterns between the north and south coasts. Styrofoam and plastic bottles were the two primary sources of macro ocean litter both annually and monthly, and most of the litter collected on the island originated from China and Vietnam, which were collectively responsible for approximately 47.5%–63.7% per month. The simulation indicated that current advection at the near-surface depths and low windage at the sea surface showed similar patterns, while medium to high windage exhibited comparable expression patterns in response to potential source regions and drifting time experiments. At either the surface with low windage or current advection at depths of 0.5 m and 1 m, macro ocean litter in the Western Philippine Sea, i.e. through the Luzon Strait between Taiwan and the Philippines, was an important contributor to the litter bulk from October to March, whereas the litter was predicted to mainly originate from the southwestern SCS from April to September. With an increasing windage effect, litter in the Taiwan Strait was predicted to be an additional major potential source. Surprisingly, a small proportion of the macro ocean litter was predicted to continuously travel in the northern SCS for a long duration (> 2 years) before drifting onto Dongsha Island. The estimated drifting time of macro ocean litter also showed monthly and directional variability. This study demonstrated that a tremendous quantity of macro ocean litter, which may cause great damage to the marine ecosystem, drifts in the ocean surface layer and is finally pushed onto beaches. Therefore, we proposed an action plan for effective ocean litter management development at regional and global spatial scales, which is vital for improving and restoring the health and sustainability of the oceanic environment.

Propagation of uncertainty in nasal spray in vitro performance models using Monte Carlo simulation: Part II. Error propagation during product performance modeling.

PubMed

Guo, Changning; Doub, William H; Kauffman, John F

2010-08-01

Monte Carlo simulations were applied to investigate the propagation of uncertainty in both input variables and response measurements on model prediction for nasal spray product performance design of experiment (DOE) models in the first part of this study, with an initial assumption that the models perfectly represent the relationship between input variables and the measured responses. In this article, we discard the initial assumption, and extended the Monte Carlo simulation study to examine the influence of both input variable variation and product performance measurement variation on the uncertainty in DOE model coefficients. The Monte Carlo simulations presented in this article illustrate the importance of careful error propagation during product performance modeling. Our results show that the error estimates based on Monte Carlo simulation result in smaller model coefficient standard deviations than those from regression methods. This suggests that the estimated standard deviations from regression may overestimate the uncertainties in the model coefficients. Monte Carlo simulations provide a simple software solution to understand the propagation of uncertainty in complex DOE models so that design space can be specified with statistically meaningful confidence levels. (c) 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Recovery of Item Parameters in the Nominal Response Model: A Comparison of Marginal Maximum Likelihood Estimation and Markov Chain Monte Carlo Estimation.

ERIC Educational Resources Information Center

Wollack, James A.; Bolt, Daniel M.; Cohen, Allan S.; Lee, Young-Sun

2002-01-01

Compared the quality of item parameter estimates for marginal maximum likelihood (MML) and Markov Chain Monte Carlo (MCMC) with the nominal response model using simulation. The quality of item parameter recovery was nearly identical for MML and MCMC, and both methods tended to produce good estimates. (SLD)

An NCME Instructional Module on Estimating Item Response Theory Models Using Markov Chain Monte Carlo Methods

ERIC Educational Resources Information Center

Kim, Jee-Seon; Bolt, Daniel M.

2007-01-01

The purpose of this ITEMS module is to provide an introduction to Markov chain Monte Carlo (MCMC) estimation for item response models. A brief description of Bayesian inference is followed by an overview of the various facets of MCMC algorithms, including discussion of prior specification, sampling procedures, and methods for evaluating chain…

Estimation of genetic variance for macro- and micro-environmental sensitivity using double hierarchical generalized linear models.

PubMed

Mulder, Han A; Rönnegård, Lars; Fikse, W Freddy; Veerkamp, Roel F; Strandberg, Erling

2013-07-04

Genetic variation for environmental sensitivity indicates that animals are genetically different in their response to environmental factors. Environmental factors are either identifiable (e.g. temperature) and called macro-environmental or unknown and called micro-environmental. The objectives of this study were to develop a statistical method to estimate genetic parameters for macro- and micro-environmental sensitivities simultaneously, to investigate bias and precision of resulting estimates of genetic parameters and to develop and evaluate use of Akaike's information criterion using h-likelihood to select the best fitting model. We assumed that genetic variation in macro- and micro-environmental sensitivities is expressed as genetic variance in the slope of a linear reaction norm and environmental variance, respectively. A reaction norm model to estimate genetic variance for macro-environmental sensitivity was combined with a structural model for residual variance to estimate genetic variance for micro-environmental sensitivity using a double hierarchical generalized linear model in ASReml. Akaike's information criterion was constructed as model selection criterion using approximated h-likelihood. Populations of sires with large half-sib offspring groups were simulated to investigate bias and precision of estimated genetic parameters. Designs with 100 sires, each with at least 100 offspring, are required to have standard deviations of estimated variances lower than 50% of the true value. When the number of offspring increased, standard deviations of estimates across replicates decreased substantially, especially for genetic variances of macro- and micro-environmental sensitivities. Standard deviations of estimated genetic correlations across replicates were quite large (between 0.1 and 0.4), especially when sires had few offspring. Practically, no bias was observed for estimates of any of the parameters. Using Akaike's information criterion the true genetic model was selected as the best statistical model in at least 90% of 100 replicates when the number of offspring per sire was 100. Application of the model to lactation milk yield in dairy cattle showed that genetic variance for micro- and macro-environmental sensitivities existed. The algorithm and model selection criterion presented here can contribute to better understand genetic control of macro- and micro-environmental sensitivities. Designs or datasets should have at least 100 sires each with 100 offspring.

On the origin of the visible light responsible for proton dose measurement using plastic optical fibers

NASA Astrophysics Data System (ADS)

Darafsheh, Arash; Taleei, Reza; Kassaee, Alireza; Finlay, Jarod C.

2017-03-01

We experimentally and by means of Monte Carlo simulations investigated the origin of the visible signal responsible for proton therapy dose measurement using bare plastic optical fibers. Experimentally, the fiber optic probe, embedded in tissue-mimicking plastics, was irradiated with a proton beam produced by a proton therapy cyclotron and the luminescence spectroscopy was performed by a CCD-coupled spectrograph to analyze the emission spectrum of the fiber tip. Monte Carlo simulations were performed using FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and optical emission of Čerenkov radiation. The spectroscopic study of proton-irradiated plastic fibers showed a continuous spectrum with shape different from that of Čerenkov radiation. The Monte Carlo simulations confirmed that the amount of the generated Čerenkov light does not follow the radiation absorbed dose in a medium. Our results show that the origin of the optical signal responsible for the proton dose measurement using bare optical fibers is not Čerenkov radiation. Our results point toward a connection between the scintillation of the plastic material of the fiber and the origin of the signal responsible for dose measurement.

Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations

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

Matsui, S., E-mail: smatsui@gpi.ac.jp; Mori, Y.; Nonaka, T.

2016-05-15

For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films andmore » Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management.« less

Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations.

PubMed

Matsui, S; Mori, Y; Nonaka, T; Hattori, T; Kasamatsu, Y; Haraguchi, D; Watanabe, Y; Uchiyama, K; Ishikawa, M

2016-05-01

For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films and Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management.

Monte Carlo simulation of cutaneous absorption and reflectance for clear, matt and dark biological tissue with varicosities: an investigation for dermatological laser

NASA Astrophysics Data System (ADS)

Klouch, Nawel; Riane, Houaria; Hamdache, Fatima; Addi, Djamel

2013-05-01

We are interested in modeling the interaction between light and biological tissue from the Monte Carlo method which is an approach used to solve modeling problems in different physical domains. Through the Monte Carlo approach we are going to try to interpret the spectral response absorption, reflectance, transmittance of normal human tissue under its three dominant tints in the visible range (350-700) nm. Then we will focus on the spectral response of the human tissue with varicosities in order to determinate the optimal conditions of operating the semiconductor laser for esthetic aim.

Monte Carlo Simulations and Generation of the SPI Response

NASA Technical Reports Server (NTRS)

Sturner, S. J.; Shrader, C. R.; Weidenspointner, G.; Teegarden, B. J.; Attie, D.; Diehl, R.; Ferguson, C.; Jean, P.; vonKienlin, A.

2003-01-01

In this paper we discuss the methods developed for the production of the INTEGRAL/SPI instrument response. The response files were produced using a suite of Monte Carlo simulation software developed at NASA/GSFC based on the GEANT-3 package available from CERN. The production of the INTEGRAL/SPI instrument response also required the development of a detailed computer mass model for SPI. We discuss our extensive investigations into methods to reduce both the computation time and storage requirements for the SPI response. We also discuss corrections to the simulated response based on our comparison of ground and inflight calibration data with MGEANT simulation.

Monte Carlo Simulations and Generation of the SPI Response

NASA Technical Reports Server (NTRS)

Sturner, S. J.; Shrader, C. R.; Weidenspointner, G.; Teegarden, B. J.; Attie, D.; Cordier, B.; Diehl, R.; Ferguson, C.; Jean, P.; vonKienlin, A.

2003-01-01

In this paper we discuss the methods developed for the production of the INTEGRAL/SPI instrument response. The response files were produced using a suite of Monte Carlo simulation software developed at NASA/GSFC based on the GEANT-3 package available from CERN. The production of the INTEGRAL/SPI instrument response also required the development of a detailed computer mass model for SPI. We discuss ow extensive investigations into methods to reduce both the computation time and storage requirements for the SPI response. We also discuss corrections to the simulated response based on our comparison of ground and infiight Calibration data with MGEANT simulations.

University community partnerships that promote evidence-based macro practice.

PubMed

Mulroy, Elizabeth A

2008-01-01

This article articulates three dimensions of EBP grounded in theory for macro practice: intention toward social change, planning and decision-making, and civic participation. These dimensions are then applied to university community partnerships that are complex community interventions. The goals of these partnerships are to improve the social environment in low-income neighborhoods through community development and reform the university as a social institution from neighborhood bystander to responsible, engaged citizen. Finally, the article introduces the concept of a planning triangle, a framework linking evidence derived from community assessments and practice-relevant research to decisive and timely action in the field.

A Temperature Sensor Based on a Polymer Optical Fiber Macro-Bend

PubMed Central

Moraleda, Alberto Tapetado; García, Carmen Vázquez; Zaballa, Joseba Zubia; Arrue, Jon

2013-01-01

The design and development of a plastic optical fiber (POF) macrobend temperature sensor is presented. The sensor has a linear response versus temperature at a fixed bend radius, with a sensitivity of 1.92·10−3 (°C)−1. The sensor system used a dummy fiber-optic sensor for reference purposes having a resolution below 0.3 °C. A comprehensive experimental analysis was carried out to provide insight into the effect of different surrounding media on practical macro-bend POF sensor implementation. Experimental results are successfully compared with bend loss calculations. PMID:24077323

Integration of P, S, Fe, and Zn nutrition signals in Arabidopsis thaliana: potential involvement of PHOSPHATE STARVATION RESPONSE 1 (PHR1)

PubMed Central

Briat, Jean-François; Rouached, Hatem; Tissot, Nicolas; Gaymard, Frédéric; Dubos, Christian

2015-01-01

Phosphate and sulfate are essential macro-elements for plant growth and development, and deficiencies in these mineral elements alter many metabolic functions. Nutritional constraints are not restricted to macro-elements. Essential metals such as zinc and iron have their homeostasis strictly genetically controlled, and deficiency or excess of these micro-elements can generate major physiological disorders, also impacting plant growth and development. Phosphate and sulfate on one hand, and zinc and iron on the other hand, are known to interact. These interactions have been partly described at the molecular and physiological levels, and are reviewed here. Furthermore the two macro-elements phosphate and sulfate not only interact between themselves but also influence zinc and iron nutrition. These intricated nutritional cross-talks are presented. The responses of plants to phosphorus, sulfur, zinc, or iron deficiencies have been widely studied considering each element separately, and some molecular actors of these regulations have been characterized in detail. Although some scarce reports have started to examine the interaction of these mineral elements two by two, a more complex analysis of the interactions and cross-talks between the signaling pathways integrating the homeostasis of these various elements is still lacking. However, a MYB-like transcription factor, PHOSPHATE STARVATION RESPONSE 1, emerges as a common regulator of phosphate, sulfate, zinc, and iron homeostasis, and its role as a potential general integrator for the control of mineral nutrition is discussed. PMID:25972885

A Strategic Response to MOOCs: How One European University Is Approaching the Challenge

ERIC Educational Resources Information Center

Brown, Mark; Costello, Eamon; Donlon, Enda; Giolla-Mhichil, Mairead Nic

2015-01-01

This paper briefly outlines some of the macro level claims, counter-claims, and unresolved debates surrounding the rapid growth of Massive Open Online Courses (MOOCs) in Higher Education. It then reports insights, experiences, and perceptions of those charged with developing a strategic institutional response to the challenges and opportunities…

Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

ERIC Educational Resources Information Center

Bancroft, Stacie L.; Bourret, Jason C.

2008-01-01

Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time.…

Online Responses towards Parental Rearing Styles Regarding Hand-Held Devices

ERIC Educational Resources Information Center

Geng, Gretchen; Disney, Leigh

2014-01-01

This article reviewed the literature on parental rearing styles and used responses from an online discussion forum to investigate people's opinions towards parental rearing styles and strategies when children use hand-held devices. Critical discourse analysis (CDA) was used as an analysis method via micro, meso and macro multi-level…

The concerted calculation of the BN-600 reactor for the deterministic and stochastic codes

NASA Astrophysics Data System (ADS)

Bogdanova, E. V.; Kuznetsov, A. N.

2017-01-01

The solution of the problem of increasing the safety of nuclear power plants implies the existence of complete and reliable information about the processes occurring in the core of a working reactor. Nowadays the Monte-Carlo method is the most general-purpose method used to calculate the neutron-physical characteristic of the reactor. But it is characterized by large time of calculation. Therefore, it may be useful to carry out coupled calculations with stochastic and deterministic codes. This article presents the results of research for possibility of combining stochastic and deterministic algorithms in calculation the reactor BN-600. This is only one part of the work, which was carried out in the framework of the graduation project at the NRC “Kurchatov Institute” in cooperation with S. S. Gorodkov and M. A. Kalugin. It is considering the 2-D layer of the BN-600 reactor core from the international benchmark test, published in the report IAEA-TECDOC-1623. Calculations of the reactor were performed with MCU code and then with a standard operative diffusion algorithm with constants taken from the Monte - Carlo computation. Macro cross-section, diffusion coefficients, the effective multiplication factor and the distribution of neutron flux and power were obtained in 15 energy groups. The reasonable agreement between stochastic and deterministic calculations of the BN-600 is observed.

Probabilistic simulation of multi-scale composite behavior

NASA Technical Reports Server (NTRS)

Liaw, D. G.; Shiao, M. C.; Singhal, S. N.; Chamis, Christos C.

1993-01-01

A methodology is developed to computationally assess the probabilistic composite material properties at all composite scale levels due to the uncertainties in the constituent (fiber and matrix) properties and in the fabrication process variables. The methodology is computationally efficient for simulating the probability distributions of material properties. The sensitivity of the probabilistic composite material property to each random variable is determined. This information can be used to reduce undesirable uncertainties in material properties at the macro scale of the composite by reducing the uncertainties in the most influential random variables at the micro scale. This methodology was implemented into the computer code PICAN (Probabilistic Integrated Composite ANalyzer). The accuracy and efficiency of this methodology are demonstrated by simulating the uncertainties in the material properties of a typical laminate and comparing the results with the Monte Carlo simulation method. The experimental data of composite material properties at all scales fall within the scatters predicted by PICAN.

CAST: a new program package for the accurate characterization of large and flexible molecular systems.

PubMed

Grebner, Christoph; Becker, Johannes; Weber, Daniel; Bellinger, Daniel; Tafipolski, Maxim; Brückner, Charlotte; Engels, Bernd

2014-09-15

The presented program package, Conformational Analysis and Search Tool (CAST) allows the accurate treatment of large and flexible (macro) molecular systems. For the determination of thermally accessible minima CAST offers the newly developed TabuSearch algorithm, but algorithms such as Monte Carlo (MC), MC with minimization, and molecular dynamics are implemented as well. For the determination of reaction paths, CAST provides the PathOpt, the Nudge Elastic band, and the umbrella sampling approach. Access to free energies is possible through the free energy perturbation approach. Along with a number of standard force fields, a newly developed symmetry-adapted perturbation theory-based force field is included. Semiempirical computations are possible through DFTB+ and MOPAC interfaces. For calculations based on density functional theory, a Message Passing Interface (MPI) interface to the Graphics Processing Unit (GPU)-accelerated TeraChem program is available. The program is available on request. Copyright © 2014 Wiley Periodicals, Inc.

Evolution: Help for the Confused.

ERIC Educational Resources Information Center

Scheer, Bradley T.

1979-01-01

Written in response to an earlier article questioning certain aspects of evolution theory. Discusses ontogeny and phylogeny, the basis of evolution, chance or purpose in evolution, micro and macro-evolution, reversibility, and the evolution processes today. (MA)

Identifying regional opportunities for accelerated timber managemnet

Treesearch

David A. Gansner; Joseph E. Barnard; Samuel F. Gingrich; Samuel F. Gingrich

1973-01-01

Describes a procedure for identifying regional opportunities for accelerated timber management and demonstrates its application. Results provide a basis for rational choices among alternative management strategies and permit meaningful micro- and macro-evaluations of treatment response.

Accuracy of Monte Carlo photon transport simulation in characterizing brachytherapy dosimeter energy-response artefacts.

PubMed

Das, R K; Li, Z; Perera, H; Williamson, J F

1996-06-01

Practical dosimeters in brachytherapy, such as thermoluminescent dosimeters (TLD) and diodes, are usually calibrated against low-energy megavoltage beams. To measure absolute dose rate near a brachytherapy source, it is necessary to establish the energy response of the detector relative to that of the calibration energy. The purpose of this paper is to assess the accuracy of Monte Carlo photon transport (MCPT) simulation in modelling the absolute detector response as a function of detector geometry and photon energy. We have exposed two different sizes of TLD-100 (LiF chips) and p-type silicon diode detectors to calibrated 60Co, HDR source (192Ir) and superficial x-ray beams. For the Scanditronix electron-field diode, the relative detector response, defined as the measured detector readings per measured unit of air kerma, varied from 38.46 V cGy-1 (40 kVp beam) to 6.22 V cGy-1 (60Co beam). Similarly for the large and small chips the same quantity varied from 2.08-3.02 nC cGy-1 and 0.171-0.244 nC cGy-1, respectively. Monte Carlo simulation was used to calculate the absorbed dose to the active volume of the detector per unit air kerma. If the Monte Carlo simulation is accurate, then the absolute detector response, which is defined as the measured detector reading per unit dose absorbed by the active detector volume, and is calculated by Monte Carlo simulation, should be a constant. For the diode, the absolute response is 5.86 +/- 0.15 (V cGy-1). For TLDs of size 3 x 3 x 1 mm3 the absolute response is 2.47 +/- 0.07 (nC cGy-1) and for TLDs of 1 x 1 x 1 mm3 it is 0.201 +/- 0.008 (nC cGy-1). From the above results we can conclude that the absolute response function of detectors (TLDs and diodes) is directly proportional to absorbed dose by the active volume of the detector and is independent of beam quality.

Estimation of genetic variance for macro- and micro-environmental sensitivity using double hierarchical generalized linear models

PubMed Central

2013-01-01

Background Genetic variation for environmental sensitivity indicates that animals are genetically different in their response to environmental factors. Environmental factors are either identifiable (e.g. temperature) and called macro-environmental or unknown and called micro-environmental. The objectives of this study were to develop a statistical method to estimate genetic parameters for macro- and micro-environmental sensitivities simultaneously, to investigate bias and precision of resulting estimates of genetic parameters and to develop and evaluate use of Akaike’s information criterion using h-likelihood to select the best fitting model. Methods We assumed that genetic variation in macro- and micro-environmental sensitivities is expressed as genetic variance in the slope of a linear reaction norm and environmental variance, respectively. A reaction norm model to estimate genetic variance for macro-environmental sensitivity was combined with a structural model for residual variance to estimate genetic variance for micro-environmental sensitivity using a double hierarchical generalized linear model in ASReml. Akaike’s information criterion was constructed as model selection criterion using approximated h-likelihood. Populations of sires with large half-sib offspring groups were simulated to investigate bias and precision of estimated genetic parameters. Results Designs with 100 sires, each with at least 100 offspring, are required to have standard deviations of estimated variances lower than 50% of the true value. When the number of offspring increased, standard deviations of estimates across replicates decreased substantially, especially for genetic variances of macro- and micro-environmental sensitivities. Standard deviations of estimated genetic correlations across replicates were quite large (between 0.1 and 0.4), especially when sires had few offspring. Practically, no bias was observed for estimates of any of the parameters. Using Akaike’s information criterion the true genetic model was selected as the best statistical model in at least 90% of 100 replicates when the number of offspring per sire was 100. Application of the model to lactation milk yield in dairy cattle showed that genetic variance for micro- and macro-environmental sensitivities existed. Conclusion The algorithm and model selection criterion presented here can contribute to better understand genetic control of macro- and micro-environmental sensitivities. Designs or datasets should have at least 100 sires each with 100 offspring. PMID:23827014

Status of the Monte Carlo library least-squares (MCLLS) approach for non-linear radiation analyzer problems

NASA Astrophysics Data System (ADS)

Gardner, Robin P.; Xu, Libai

2009-10-01

The Center for Engineering Applications of Radioisotopes (CEAR) has been working for over a decade on the Monte Carlo library least-squares (MCLLS) approach for treating non-linear radiation analyzer problems including: (1) prompt gamma-ray neutron activation analysis (PGNAA) for bulk analysis, (2) energy-dispersive X-ray fluorescence (EDXRF) analyzers, and (3) carbon/oxygen tool analysis in oil well logging. This approach essentially consists of using Monte Carlo simulation to generate the libraries of all the elements to be analyzed plus any other required background libraries. These libraries are then used in the linear library least-squares (LLS) approach with unknown sample spectra to analyze for all elements in the sample. Iterations of this are used until the LLS values agree with the composition used to generate the libraries. The current status of the methods (and topics) necessary to implement the MCLLS approach is reported. This includes: (1) the Monte Carlo codes such as CEARXRF, CEARCPG, and CEARCO for forward generation of the necessary elemental library spectra for the LLS calculation for X-ray fluorescence, neutron capture prompt gamma-ray analyzers, and carbon/oxygen tools; (2) the correction of spectral pulse pile-up (PPU) distortion by Monte Carlo simulation with the code CEARIPPU; (3) generation of detector response functions (DRF) for detectors with linear and non-linear responses for Monte Carlo simulation of pulse-height spectra; and (4) the use of the differential operator (DO) technique to make the necessary iterations for non-linear responses practical. In addition to commonly analyzed single spectra, coincidence spectra or even two-dimensional (2-D) coincidence spectra can also be used in the MCLLS approach and may provide more accurate results.

Macro- and micro-designed chitosan-alginate scaffold architecture by three-dimensional printing and directional freezing.

PubMed

Reed, Stephanie; Lau, Grace; Delattre, Benjamin; Lopez, David Don; Tomsia, Antoni P; Wu, Benjamin M

2016-01-07

While many tissue-engineered constructs aim to treat cartilage defects, most involve chondrocyte or stem cell seeding on scaffolds. The clinical application of cell-based techniques is limited due to the cost of maintaining cellular constructs on the shelf, potential immune response to allogeneic cell lines, and autologous chondrocyte sources requiring biopsy from already diseased or injured, scarce tissue. An acellular scaffold that can induce endogenous influx and homogeneous distribution of native stem cells from bone marrow holds great promise for cartilage regeneration. This study aims to develop such an acellular scaffold using designed, channeled architecture that simultaneously models the native zones of articular cartilage and subchondral bone. Highly porous, hydrophilic chitosan-alginate (Ch-Al) scaffolds were fabricated in three-dimensionally printed (3DP) molds designed to create millimeter scale macro-channels. Different polymer preform casting techniques were employed to produce scaffolds from both negative and positive 3DP molds. Macro-channeled scaffolds improved cell suspension distribution and uptake overly randomly porous scaffolds, with a wicking volumetric flow rate of 445.6 ± 30.3 mm(3) s(-1) for aqueous solutions and 177 ± 16 mm(3) s(-1) for blood. Additionally, directional freezing was applied to Ch-Al scaffolds, resulting in lamellar pores measuring 300 μm and 50 μm on the long and short axes, thus creating micrometer scale micro-channels. After directionally freezing Ch-Al solution cast in 3DP molds, the combined macro- and micro-channeled scaffold architecture enhanced cell suspension uptake beyond either macro- or micro-channels alone, reaching a volumetric flow rate of 1782.1 ± 48 mm(3) s(-1) for aqueous solutions and 440.9 ± 0.5 mm(3) s(-1) for blood. By combining 3DP and directional freezing, we can control the micro- and macro-architecture of Ch-Al to drastically improve cell influx into and distribution within the scaffold, while achieving porous zones that mimic articular cartilage zonal architecture. In future applications, precisely controlled micro- and macro-channels have the potential to assist immediate endogenous bone marrow uptake, stimulate chondrogenesis, and encourage vascularization of bone in an osteochondral scaffold.

Monte Carlo study on pulse response of underwater optical channel

NASA Astrophysics Data System (ADS)

Li, Jing; Ma, Yong; Zhou, Qunqun; Zhou, Bo; Wang, Hongyuan

2012-06-01

Pulse response of the underwater wireless optical channel is significant for the analysis of channel capacity and error probability. Traditional vector radiative transfer theory (VRT) is not able to deal with the effect of receiving aperture. On the other hand, general water tank experiments cannot acquire an accurate pulse response due to the limited time resolution of the photo-electronic detector. We present a Monte Carlo simulation model to extract the time-domain pulse response undersea. In comparison with the VRT model, a more accurate pulse response for practical ocean communications could be achieved through statistical analysis of the received photons. The proposed model is more reasonable for the study of the underwater optical channel.

Sense of Community as Construct and Theory: Authors' Response to McMillan

ERIC Educational Resources Information Center

Nowell, Branda; Boyd, Neil

2011-01-01

In this article, we respond to criticisms posed by McMillan (2011) of our recent paper, "Viewing Community as Responsibility as well as a Resource: Deconstructing the Theoretical Roots of Psychological Sense of Community." We clarify that the focus of our article was to explore the macro theoretical frameworks and second-order assumptions that…

Changing household responses to drought in Tharaka, Kenya: vulnerability, persistence and challenge.

PubMed

Smucker, Thomas A; Wisner, Ben

2008-06-01

Drought is a recurring challenge to the livelihoods of those living in Tharaka District, Kenya, situated in the semi-arid zone to the east of Mount Kenya, from the lowest slopes of the mountain to the banks of the Tana River. This part of Kenya has been marginal to the economic and political life of Kenya from the colonial period until the present day. A study of more than 30 years of change in how people in Tharaka cope with drought reveals resilience in the face of major macro-level transformations, which include privatisation of landownership, population growth, political decentralisation, increased conflict over natural resources, different market conditions, and environmental shifts. However, the study also shows troubling signs of increased use of drought responses that are incompatible with long-term agrarian livelihoods. Government policy needs to address the challenge of drought under these new macro conditions if sustainable human development is to be achieved.

Using Stan for Item Response Theory Models

ERIC Educational Resources Information Center

Ames, Allison J.; Au, Chi Hang

2018-01-01

Stan is a flexible probabilistic programming language providing full Bayesian inference through Hamiltonian Monte Carlo algorithms. The benefits of Hamiltonian Monte Carlo include improved efficiency and faster inference, when compared to other MCMC software implementations. Users can interface with Stan through a variety of computing…

Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone?

PubMed

Zerlin, R A; Henry, R

2014-05-01

Benthic macro-invertebrates are important components of freshwater ecosystems which are involved in ecological processes such as energy transfer between detritus and consumers and organic matter recycling. The aim of this work was to investigate the variation in organism richness, diversity and density of benthic fauna during the annual cycle in Camargo Lake, a lake marginal to Paranapanema River, southeast Brazil. The correlation of environmental factors with community attributes of the macro-benthic fauna was assessed. Since Camargo Lake is connected to the river, we tested the hypothesis that water level variation is the main regulating factor of environmental variables and of the composition and abundance of benthic macro-invertebrates. The results indicated that lake depth varied with rainfall, being the highest at the end of the rising water period and the lowest at the beginning of this period. The sediment granulometry was more heterogeneous at the bottom of the lake by the end of the high water period. The benthic macro-invertebrate fauna was composed by 15 taxa. The Diptera order was represented by seven taxa and had greater richness in relation to other taxa. This group was responsible for 60% of the total abundance of organisms, followed by Ephemeroptera (22%) and Anellida (16%). Significant differences were observed over time in total richness and, in density of Narapa bonettoi, Chaoborus, Ablabesmyia gr. annulata, Chironomus gigas, Larsia fittkau, and Procladius sp. 2. Total taxa richness correlated negatively with water pH, transparency, conductivity, and bottom water oxygen. Higher positive correlations were found between the densities of some taxa and bottom water oxygen, conductivity and very fine sand, silt + clay of sediment, while negative correlations were recorded with organic matter, and fine, medium and coarse sand, bottom water temperature, mean temperature and rainfall. The significant temporal difference in water level was associated with changes in abiotic factors and macro-invertebrate community attributes.

[Heavy metal pollution ecology of macro-fungi: research advances and expectation].

PubMed

Zhou, Qi-xing; An, Xin-long; Wei, Shu-he

2008-08-01

Macro-fungi are the main component of biosphere and one of the ecological resources, and play very important roles in matter cycling and in maintaining ecological balances. This paper summarized and reviewed the research advances in the eco-toxicological effects of heavy metals on macro-fungi, the bioaccumulation function of macro-fungi on heavy metals, the ecological adaptation mechanisms of macro-fungi to heavy metal pollution, the role of macro-fungi as a bio-indicator of heavy metal pollution, and the potential of macro-fungi in the ecological remediation of contaminated environment. To strengthen the researches on the heavy metal pollution ecology of macro-fungi would be of practical significance in the reasonable utilization of macro-fungi resources and in the ecological remediation of contaminated environment.

Applying Monte-Carlo simulations to optimize an inelastic neutron scattering system for soil carbon analysis

USDA-ARS?s Scientific Manuscript database

Computer Monte-Carlo (MC) simulations (Geant4) of neutron propagation and acquisition of gamma response from soil samples was applied to evaluate INS system performance characteristic [sensitivity, minimal detectable level (MDL)] for soil carbon measurement. The INS system model with best performanc...

Using Monte Carlo Techniques to Demonstrate the Meaning and Implications of Multicollinearity

ERIC Educational Resources Information Center

Vaughan, Timothy S.; Berry, Kelly E.

2005-01-01

This article presents an in-class Monte Carlo demonstration, designed to demonstrate to students the implications of multicollinearity in a multiple regression study. In the demonstration, students already familiar with multiple regression concepts are presented with a scenario in which the "true" relationship between the response and…

Comparison of the electromagnetic responses of C 12 obtained from the Green's function Monte Carlo and spectral function approaches

DOE PAGES

Rocco, Noemi; Lovato, Alessandro; Benhar, Omar

2016-12-23

Here, the electromagnetic responses of carbon obtained from the Green's function Monte Carlo and spectral function approaches using the same dynamical input are compared in the kinematical region corresponding to momentum transfer in the range 300–570 MeV. The results of our analysis, aimed at pinning down the limits of applicability of the approximations involved in the two schemes, indicate that the factorization ansatz underlying the spectral function formalism provides remarkably accurate results down to momentum transfer as low as 300 MeV. On the other hand, it appears that at 570 MeV relativistic corrections to the electromagnetic current not included inmore » the Monte Carlo calculations may play a significant role in the transverse channel.« less

Comparison of the electromagnetic responses of C 12 obtained from the Green's function Monte Carlo and spectral function approaches

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

Rocco, Noemi; Lovato, Alessandro; Benhar, Omar

Here, the electromagnetic responses of carbon obtained from the Green's function Monte Carlo and spectral function approaches using the same dynamical input are compared in the kinematical region corresponding to momentum transfer in the range 300–570 MeV. The results of our analysis, aimed at pinning down the limits of applicability of the approximations involved in the two schemes, indicate that the factorization ansatz underlying the spectral function formalism provides remarkably accurate results down to momentum transfer as low as 300 MeV. On the other hand, it appears that at 570 MeV relativistic corrections to the electromagnetic current not included inmore » the Monte Carlo calculations may play a significant role in the transverse channel.« less

A Variational Formulation of Macro-Particle Algorithms for Kinetic Plasma Simulations

NASA Astrophysics Data System (ADS)

Shadwick, B. A.

2013-10-01

Macro-particle based simulations methods are in widespread use in plasma physics; their computational efficiency and intuitive nature are largely responsible for their longevity. In the main, these algorithms are formulated by approximating the continuous equations of motion. For systems governed by a variational principle (such as collisionless plasmas), approximations of the equations of motion is known to introduce anomalous behavior, especially in system invariants. We present a variational formulation of particle algorithms for plasma simulation based on a reduction of the distribution function onto a finite collection of macro-particles. As in the usual Particle-In-Cell (PIC) formulation, these macro-particles have a definite momentum and are spatially extended. The primary advantage of this approach is the preservation of the link between symmetries and conservation laws. For example, nothing in the reduction introduces explicit time dependence to the system and, therefore, the continuous-time equations of motion exactly conserve energy; thus, these models are free of grid-heating. In addition, the variational formulation allows for constructing models of arbitrary spatial and temporal order. In contrast, the overall accuracy of the usual PIC algorithm is at most second due to the nature of the force interpolation between the gridded field quantities and the (continuous) particle position. Again in contrast to the usual PIC algorithm, here the macro-particle shape is arbitrary; the spatial extent is completely decoupled from both the grid-size and the ``smoothness'' of the shape; smoother particle shapes are not necessarily larger. For simplicity, we restrict our discussion to one-dimensional, non-relativistic, un-magnetized, electrostatic plasmas. We comment on the extension to the electromagnetic case. Supported by the US DoE under contract numbers DE-FG02-08ER55000 and DE-SC0008382.

Comparison of UWCC MOX fuel measurements to MCNP-REN calculations

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

Abhold, M.; Baker, M.; Jie, R.

1998-12-31

The development of neutron coincidence counting has greatly improved the accuracy and versatility of neutron-based techniques to assay fissile materials. Today, the shift register analyzer connected to either a passive or active neutron detector is widely used by both domestic and international safeguards organizations. The continued development of these techniques and detectors makes extensive use of the predictions of detector response through the use of Monte Carlo techniques in conjunction with the point reactor model. Unfortunately, the point reactor model, as it is currently used, fails to accurately predict detector response in highly multiplying mediums such as mixed-oxide (MOX) lightmore » water reactor fuel assemblies. For this reason, efforts have been made to modify the currently used Monte Carlo codes and to develop new analytical methods so that this model is not required to predict detector response. The authors describe their efforts to modify a widely used Monte Carlo code for this purpose and also compare calculational results with experimental measurements.« less

Nano/macro porous bioactive glass scaffold

NASA Astrophysics Data System (ADS)

Wang, Shaojie

Bioactive glass (BG) and ceramics have been widely studied and developed as implants to replace hard tissues of the musculo-skeletal system, such as bones and teeth. Recently, instead of using bulk materials, which usually do not degrade rapidly enough and may remain in the human body for a long time, the idea of bioscaffold for tissue regeneration has generated much interest. An ideal bioscaffold is a porous material that would not only provide a three-dimensional structure for the regeneration of natural tissue, but also degrade gradually and, eventually be replaced by the natural tissue completely. Among various material choices the nano-macro dual porous BG appears as the most promising candidate for bioscaffold applications. Here macropores facilitate tissue growth while nanopores control degradation and enhance cell response. The surface area, which controls the degradation of scaffold can also be tuned by changing the nanopore size. However, fabrication of such 3D structure with desirable nano and macro pores has remained challenging. In this dissertation, sol-gel process combined with spinodal decomposition or polymer sponge replication method has been developed to fabricate the nano-macro porous BG scaffolds. Macropores up to 100microm are created by freezing polymer induced spinodal structure through sol-gel transition, while larger macropores (>200um) of predetermined size are obtained by the polymer sponge replication technique. The size of nanopores, which are inherent to the sol-gel method of glass fabrication, has been tailored using several approaches: Before gel point, small nanopores are generated using acid catalyst that leads to weakly-branched polymer-like network. On the other hand, larger nanopores are created with the base-catalyzed gel with highly-branched cluster-like structure. After the gel point, the nanostructure can be further modified by manipulating the sintering temperature and/or the ammonia concentration used in the solvent exchange process. Although both techniques lower the surface area of BG scaffolds, the temperature-dependent sintering process closes nanopores through densification, while the concentration-dependent solvent exchange process enlarges nanopores through Ostwald-ripening type coarsening. Therefore, nanopore size and surface area of BG scaffold are independently controlled using these methods. In vitro cell and in vivo animal tissue responses have been investigated to evaluate the performance of the nano-macro porous BG scaffold. The cells are found to migrate and penetrate deep into the 3D nano-macro porous structure, while exhibiting excellent adhesion to the bioscaffold surface. Importantly, the new tissue with both blood vessels and collagen fibers is formed deep inside the implanted scaffolds without obvious inflammatory reaction. Furthermore, our observations show biological benefits of the nanopores in the BG scaffold. In comparison to BG scaffold without nanopores, cells migrate and penetrate into nano-macro dual-porous BG scaffold faster and deeper mainly because of the increase of surface area. To study the effect of nanopore topography, we fabricated BG scaffolds with the same surface area but different nanopore sizes. It is found that the initial cell attachment is significantly enhanced on the BG scaffold with the same surface area but smaller nanopores size, indicating that the nanopore topography strongly influences the performance of BG scaffold. In conclusion, the present results demonstrate most clearly the usefulness of our nano-macro dual-porous BG as a novel and superior 3D bioscaffold for regenerative medicine and hard tissue engineering.

Potential macro-detritivore range expansion into the subarctic stimulates litter decomposition: a new positive feedback mechanism to climate change?

PubMed

van Geffen, Koert G; Berg, Matty P; Aerts, Rien

2011-12-01

As a result of low decomposition rates, high-latitude ecosystems store large amounts of carbon. Litter decomposition in these ecosystems is constrained by harsh abiotic conditions, but also by the absence of macro-detritivores. We have studied the potential effects of their climate change-driven northward range expansion on the decomposition of two contrasting subarctic litter types. Litter of Alnus incana and Betula pubescens was incubated in microcosms together with monocultures and all possible combinations of three functionally different macro-detritivores (the earthworm Lumbricus rubellus, isopod Oniscus asellus, and millipede Julus scandinavius). Our results show that these macro-detritivores stimulated decomposition, especially of the high-quality A. incana litter and that the macro-detritivores tested differed in their decomposition-stimulating effects, with earthworms having the largest influence. Decomposition processes increased with increasing number of macro-detritivore species, and positive net diveristy effects occurred in several macro-detritivore treatments. However, after correction for macro-detritivore biomass, all interspecific differences in macro-detritivore effects, as well as the positive effects of species number on subarctic litter decomposition disappeared. The net diversity effects also appeared to be driven by variation in biomass, with a possible exception of net diversity effects in mass loss. Based on these results, we conclude that the expected climate change-induced range expansion of macro-detritivores into subarctic regions is likely to result in accelerated decomposition rates. Our results also indicate that the magnitude of macro-detritivore effects on subarctic decomposition will mainly depend on macro-detritivore biomass, rather than on macro-detritivore species number or identity.

Monte Carlo Simulation of a Segmented Detector for Low-Energy Electron Antineutrinos

NASA Astrophysics Data System (ADS)

Qomi, H. Akhtari; Safari, M. J.; Davani, F. Abbasi

2017-11-01

Detection of low-energy electron antineutrinos is of importance for several purposes, such as ex-vessel reactor monitoring, neutrino oscillation studies, etc. The inverse beta decay (IBD) is the interaction that is responsible for detection mechanism in (organic) plastic scintillation detectors. Here, a detailed study will be presented dealing with the radiation and optical transport simulation of a typical segmented antineutrino detector withMonte Carlo method using MCNPX and FLUKA codes. This study shows different aspects of the detector, benefiting from inherent capabilities of the Monte Carlo simulation codes.

Tracing the transition of a macro electron shuttle into nonlinear response

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

Kim, Chulki; Prada, Marta; Qin, Hua

We present a study on a macroscopic electron shuttle in the transition from linear to nonlinear response. The shuttle consists of a classical mechanical pendulum situated between two capacitor plates. The metallic pendulum enables mechanical transfer of electrons between the plates, hence allowing to directly trace electron shuttling in the time domain. By applying a high voltage to the plates, we drive the system into a controlled nonlinear response, where we observe period doubling.

Modeling plasticity by non-continuous deformation

NASA Astrophysics Data System (ADS)

Ben-Shmuel, Yaron; Altus, Eli

2017-10-01

Plasticity and failure theories are still subjects of intense research. Engineering constitutive models on the macroscale which are based on micro characteristics are very much in need. This study is motivated by the observation that continuum assumptions in plasticity in which neighbour material elements are inseparable at all-time are physically impossible, since local detachments, slips and neighbour switching must operate, i.e. non-continuous deformation. Material microstructure is modelled herein by a set of point elements (particles) interacting with their neighbours. Each particle can detach from and/or attach with its neighbours during deformation. Simulations on two- dimensional configurations subjected to uniaxial compression cycle are conducted. Stochastic heterogeneity is controlled by a single "disorder" parameter. It was found that (a) macro response resembles typical elasto-plastic behaviour; (b) plastic energy is proportional to the number of detachments; (c) residual plastic strain is proportional to the number of attachments, and (d) volume is preserved, which is consistent with macro plastic deformation. Rigid body displacements of local groups of elements are also observed. Higher disorder decreases the macro elastic moduli and increases plastic energy. Evolution of anisotropic effects is obtained with no additional parameters.

The effects of macro-level interventions on addictive behavior.

PubMed

Pacula, R L; Chaloupka, F J

2001-12-01

Drug addictions are often viewed as compulsive behaviors, not sensitive to the typical rules of self-discipline or market forces. Nonetheless, many governments try to discourage consumption of addictive substances through macro policy tools, such as taxation, regulation and prohibition, in an effort to reduce the harmful consequences that result from their consumption. The government's ability to discourage this type of behavior through these macro policies depends critically on the responsiveness of addictive consumption to market interventions. This paper reviews the growing literature that applies economic principles to the analysis of "substance abuse." Specifically, we review the impact of prices and public policies on the demands for tobacco, alcohol, and illicit drugs. The findings from these studies clearly demonstrate that even addictive behaviors are sensitive to changes in the price of substances being abused. When the full price of the addictive good rises, consumption of that good falls, even among abusers. Therefore, public policies that raise the full price of a drug to a consumer, particularly youth, are likely to result in long run reductions in rates of addiction.

A cross-taxa study using environmental DNA/RNA metabarcoding to measure biological impacts of offshore oil and gas drilling and production operations.

PubMed

Laroche, Olivier; Wood, Susanna A; Tremblay, Louis A; Ellis, Joanne I; Lear, Gavin; Pochon, Xavier

2018-02-01

Standardized ecosystem-based monitoring surveys are critical for providing information on marine ecosystem health. Environmental DNA/RNA (eDNA/eRNA) metabarcoding may facilitate such surveys by quickly and effectively characterizing multi-trophic levels. In this study, we assessed the suitability of eDNA/eRNA metabarcoding to evaluate changes in benthic assemblages of bacteria, Foraminifera and other eukaryotes along transects at three offshore oil and gas (O&G) drilling and production sites, and compared these to morphologically characterized macro-faunal assemblages. Bacterial communities were the most responsive to O&G activities, followed by Foraminifera, and macro-fauna (the latter assessed by morphology). The molecular approach enabled detection of hydrocarbon degrading taxa such as the bacteria Alcanivorax and Microbulbifer at petroleum impacted stations. Most identified indicator taxa, notably among macro-fauna, were highly specific to site conditions. Based on our results we suggest that eDNA/eRNA metabarcoding can be used as a stand-alone method for biodiversity assessment or as a complement to morphology-based monitoring approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

Macro- and meiofaunal community features in the critical environmental system of a tourist harbour (Rapallo, Ligurian Sea, NW Mediterranean).

PubMed

Harriague, Anabella Covazzi; Albertelli, Giancarlo; Misic, Cristina

2012-03-01

Two samplings were carried out in a tourist harbour, during low and high touristic activity periods, to study the macro- and meiofaunal communities in relation to the environmental features. A multivariate analysis showed close relationships: the maritime traffic disturbance and the food quality and availability drive the spatial differences of the assemblages, dividing the area into three sub-areas: the area near the Boate torrent that empties into the harbour, the harbour proper, and the external area (just outside the harbour). Macro- and meiofauna showed notably different temporal trends, indicating competition for the resources and the higher sensitivity of the macrofauna to environmental pressures. The macrofauna strongly decreased as a response to heavier harbour activities, with increasing turbidity also affecting the external station outside the harbour. Finally, comparing the macrofaunal communities to those sampled in the same area 10 years before, we found that their abundance, richness and biomass had notably decreased, highlighting the worsening of the harbour environment due to the increased organic load and turbidity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dielectric response of periodic systems from quantum Monte Carlo calculations.

PubMed

Umari, P; Willamson, A J; Galli, Giulia; Marzari, Nicola

2005-11-11

We present a novel approach that allows us to calculate the dielectric response of periodic systems in the quantum Monte Carlo formalism. We employ a many-body generalization for the electric-enthalpy functional, where the coupling with the field is expressed via the Berry-phase formulation for the macroscopic polarization. A self-consistent local Hamiltonian then determines the ground-state wave function, allowing for accurate diffusion quantum Monte Carlo calculations where the polarization's fixed point is estimated from the average on an iterative sequence, sampled via forward walking. This approach has been validated for the case of an isolated hydrogen atom and then applied to a periodic system, to calculate the dielectric susceptibility of molecular-hydrogen chains. The results found are in excellent agreement with the best estimates obtained from the extrapolation of quantum-chemistry calculations.

Designing PolyHEMA Substrates that Mimic the Viscoelastic Response of Soft Tissue

PubMed Central

Holt, Brian; Tripathi, Anubhav; Morgan, Jeffrey R.

2011-01-01

Matching the mechanical properties of a biomaterial to soft tissue is often overlooked despite the fact that it’s well known that cells respond to and are capable of changing their mechanical environment. In this paper, we used NaCl and alginate beads as porogens to make a series of micro- and macro-porous pHEMA substrates [poly(2-hydroxyethly methacrylate)] and quantified their mechanical behavior under low-magnitude shear loads over physiologically relevant frequencies. Using a stress-controlled rheometer, we performed isothermal (37°C) frequency response experiments between 0.628 and 75.4 rad/s [0.01–12Hz] at 0.1% strain. Both micro- and macro-porous pHEMA substrates were predominately elastic in nature with a narrow range of G′ and G″ values that mimicked the response of human skin. The magnitude of the G′ and G″ values of the macro-porous substrates were designed to closely match human skin. To determine how cell growth might alter their mechanical properties, pHEMA substrates were functionalized and human skin fibroblasts grown on them for fourteen days. As a result of cell growth, the magnitude of G′ and G″ increased at low frequencies while also altering the degree of high frequency dependence, indicating that cellular interactions with the micro-pore infrastructure has a profound effect on the viscoelastic behavior of the substrates. These data could be fit to a mathematical model describing a soft solid. A quantitative understanding of the mechanical behavior of biomaterials in regimes that are physiologically relevant and how these mechanics may change after implantation may aid in the design of new materials. PMID:21496821

Lemons to Lemonade: How Five Challenges in Teaching Macro Practice Helped to Strengthen Our Course

ERIC Educational Resources Information Center

Dooley, Joe; Sellers, Sherril; Gordon-Hempe, Cornelia

2009-01-01

Teaching macro practice can be challenging. While students have some concepts of what macro practice entails, their knowledge may be limited and sometimes inaccurate. Moreover, students may be reluctant to engage in macro change efforts. Given the scarcity of literature regarding teaching macro practice and the growing importance of it in social…

Unexplained high thyroid stimulating hormone: a "BIG" problem.

PubMed

Mendoza, Heidi; Connacher, Alan; Srivastava, Rajeev

2009-01-01

Macro-hormones and macro-enzymes are high molecular weight conjugates of hormones or enzymes, respectively, often with immunoglobulins. These are referred to as macromolecular complexes, and may cause artefactually elevated biochemical tests results. Macro enzymes of the most commonly measured serum enzymes have been identified and are recognised as a source of elevated measurements that may cause diagnostic confusion; macro-creatine kinase and macro-amylase are the two better known macro-enzymes in clinical practice. Literature on macro-hormones is largely restricted to macro-prolactin. We present a case of a clinically euthyroid patient, who had persistently elevated thyroid stimulating hormone (TSH) but free thyroxine within the reference limits. She underwent repeated thyroid investigations and thyroid hormone interference studies, until macro-TSH was identified as the most likely cause of unexplained elevated TSH. Following the identification and characterisation of this biochemical abnormality, she is no longer subject to repeated blood tests for assessment of thyroid function; the patient currently remains clinically euthyroid.

Calculation of response matrix of CaSO 4:Dy based neutron dosimeter using Monte Carlo code FLUKA and measurement of 241Am-Be spectra

NASA Astrophysics Data System (ADS)

Chatterjee, S.; Bakshi, A. K.; Tripathy, S. P.

2010-09-01

Response matrix for CaSO 4:Dy based neutron dosimeter was generated using Monte Carlo code FLUKA in the energy range thermal to 20 MeV for a set of eight Bonner spheres of diameter 3-12″ including the bare one. Response of the neutron dosimeter was measured for the above set of spheres for 241Am-Be neutron source covered with 2 mm lead. An analytical expression for the response function was devised as a function of sphere mass. Using Frascati Unfolding Iteration Tool (FRUIT) unfolding code, the neutron spectrum of 241Am-Be was unfolded and compared with standard IAEA spectrum for the same.

Influence of Tow Architecture on Compaction and Nesting in Textile Preforms

NASA Astrophysics Data System (ADS)

Yousaf, Z.; Potluri, P.; Withers, P. J.

2017-04-01

Transverse compression response of tows during processes such as vacuum infusion or autoclave curing has significant influence on resin permeability in fabrics as well as the laminate thickness, fibre volume fraction and tow orientations in the finished composite. This paper reports macro -scale deformations in dry fibre assemblies due to transverse compaction. In this study, influence of weave geometry and the presence of interlacements or stitches on the ply-level compaction as well as nesting have been investigated. 2D woven fabrics with a variety of interlacement patterns - plain, twill and sateen- as well as stitched Non-crimp (NCF) fabrics have been investigated for macro-level deformations. Compression response of single layer and multilayer stacks has been studied as a function of external pressure in order to establish nesting behaviour. It appears that the degree of individual ply compaction and degree of nesting between the plies are influenced by tow architectures. Inter-tow spacing and stitching thread thickness appears to influence the degree of nesting in non-crimp fabrics.

A Markov Chain Monte Carlo Approach to Confirmatory Item Factor Analysis

ERIC Educational Resources Information Center

Edwards, Michael C.

2010-01-01

Item factor analysis has a rich tradition in both the structural equation modeling and item response theory frameworks. The goal of this paper is to demonstrate a novel combination of various Markov chain Monte Carlo (MCMC) estimation routines to estimate parameters of a wide variety of confirmatory item factor analysis models. Further, I show…

Monte carlo study of MOSFET packaging, optimised for improved energy response: single MOSFET filtration.

PubMed

Othman, M A R; Cutajar, D L; Hardcastle, N; Guatelli, S; Rosenfeld, A B

2010-09-01

Monte Carlo simulations of the energy response of a conventionally packaged single metal-oxide field effect transistors (MOSFET) detector were performed with the goal of improving MOSFET energy dependence for personal accident or military dosimetry. The MOSFET detector packaging was optimised. Two different 'drop-in' design packages for a single MOSFET detector were modelled and optimised using the GEANT4 Monte Carlo toolkit. Absorbed photon dose simulations of the MOSFET dosemeter placed in free-air response, corresponding to the absorbed doses at depths of 0.07 mm (D(w)(0.07)) and 10 mm (D(w)(10)) in a water equivalent phantom of size 30 x 30 x 30 cm(3) for photon energies of 0.015-2 MeV were performed. Energy dependence was reduced to within + or - 60 % for photon energies 0.06-2 MeV for both D(w)(0.07) and D(w)(10). Variations in the response for photon energies of 15-60 keV were 200 and 330 % for D(w)(0.07) and D(w)(10), respectively. The obtained energy dependence was reduced compared with that for conventionally packaged MOSFET detectors, which usually exhibit a 500-700 % over-response when used in free-air geometry.

The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR 1000 plus.

PubMed

Bohm, Tim D; Griffin, Sheridan L; DeLuca, Paul M; DeWerd, Larry A

2005-04-01

The determination of the air kerma strength of a brachytherapy seed is necessary for effective treatment planning. Well ionization chambers are used on site at therapy clinics to determine the air kerma strength of seeds. In this work, the response of the Standard Imaging HDR 1000 Plus well chamber to ambient pressure is examined using Monte Carlo calculations. The experimental work examining the response of this chamber as well as other chambers is presented in a companion paper. The Monte Carlo results show that for low-energy photon sources, the application of the standard temperature pressure PTP correction factor produces an over-response at the reduced air densities/pressures corresponding to high elevations. With photon sources of 20 to 40 keV, the normalized PTP corrected chamber response is as much as 10% to 20% over unity for air densities/pressures corresponding to an elevation of 3048 m (10000 ft) above sea level. At air densities corresponding to an elevation of 1524 m (5000 ft), the normalized PTP-corrected chamber response is 5% to 10% over unity for these photon sources. With higher-energy photon sources (>100 keV), the normalized PTP corrected chamber response is near unity. For low-energy beta sources of 0.25 to 0.50 MeV, the normalized PTP-corrected chamber response is as much as 4% to 12% over unity for air densities/pressures corresponding to an elevation of 3048 m (10000 ft) above sea level. Higher-energy beta sources (>0.75 MeV) have a normalized PTP corrected chamber response near unity. Comparing calculated and measured chamber responses for common 103Pd- and 125I-based brachytherapy seeds show agreement to within 2.7% and 1.9%, respectively. Comparing MCNP calculated chamber responses with EGSnrc calculated chamber responses show agreement to within 3.1% at photon energies of 20 to 40 keV. We conclude that Monte Carlo transport calculations accurately model the response of this well chamber. Further, applying the standard PTP correction factor for this well chamber is insufficient in accounting for the change in chamber response with air pressure for low-energy (<100 keV) photon and low-energy (<0.75 MeV)beta sources.

BROMOC suite: Monte Carlo/Brownian dynamics suite for studies of ion permeation and DNA transport in biological and artificial pores with effective potentials.

PubMed

De Biase, Pablo M; Markosyan, Suren; Noskov, Sergei

2015-02-05

The transport of ions and solutes by biological pores is central for cellular processes and has a variety of applications in modern biotechnology. The time scale involved in the polymer transport across a nanopore is beyond the accessibility of conventional MD simulations. Moreover, experimental studies lack sufficient resolution to provide details on the molecular underpinning of the transport mechanisms. BROMOC, the code presented herein, performs Brownian dynamics simulations, both serial and parallel, up to several milliseconds long. BROMOC can be used to model large biological systems. IMC-MACRO software allows for the development of effective potentials for solute-ion interactions based on radial distribution function from all-atom MD. BROMOC Suite also provides a versatile set of tools to do a wide variety of preprocessing and postsimulation analysis. We illustrate a potential application with ion and ssDNA transport in MspA nanopore. © 2014 Wiley Periodicals, Inc.

Kinetic modeling of streamer penetration into de-ionized water

NASA Astrophysics Data System (ADS)

Levko, Dmitry; Sharma, Ashish; Raja, Laxminarayan L.

2018-03-01

Interest in plasma-liquid interaction phenomena has grown in recent years due to applications in plasma medicine, water purification, and plasma-hydrocarbon reforming. The plasma in contact with liquid is generated, for example, using the plasma jets or streamer discharges. The interaction between the streamer and water can cause both physical and chemical modifications of the liquid. In this paper, the interaction between an anode-directed streamer and the de-ionized water is studied using one-dimensional particle-in-cell Monte Carlo collisions model. In this model, plasma species in both gas and liquid phase are considered as the macro-particles. We find that the penetration of the streamer head into the liquid causes ionization of water molecules by electron impact, a process which is usually ignored in the fluid models. The main charge carriers in the liquid phase are negative water ions which agree with earlier experimental and computational modeling studies. Additionally, we observe an ion-rich sheath in the vicinity of the water surface on the gas side.

Some Interesting Applications of Probabilistic Techiques in Structural Dynamic Analysis of Rocket Engines

NASA Technical Reports Server (NTRS)

Brown, Andrew M.

2014-01-01

Numerical and Analytical methods developed to determine damage accumulation in specific engine components when speed variation included. Dither Life Ratio shown to be well over factor of 2 for specific example. Steady-State assumption shown to be accurate for most turbopump cases, allowing rapid calculation of DLR. If hot-fire speed data unknown, Monte Carlo method developed that uses speed statistics for similar engines. Application of techniques allow analyst to reduce both uncertainty and excess conservatism. High values of DLR could allow previously unacceptable part to pass HCF criteria without redesign. Given benefit and ease of implementation, recommend that any finite life turbomachine component analysis adopt these techniques. Probability Values calculated, compared, and evaluated for several industry-proposed methods for combining random and harmonic loads. Two new excel macros written to calculate combined load for any specific probability level. Closed form Curve fits generated for widely used 3(sigma) and 2(sigma) probability levels. For design of lightweight aerospace components, obtaining accurate, reproducible, statistically meaningful answer critical.

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2013-03-02

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of √s = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K s and Λ particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scalemore » uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2–5 % for central isolated hadrons and 1–3 % for the final calorimeter jet energy scale.« less

Innovation and Entrepreneurship: Trials of Japanese Universities

ERIC Educational Resources Information Center

Shi, Lili; Yonezawa, Akiyoshi

2012-01-01

This article examines the Japanese response in terms of innovation capacity and entrepreneurship enhancement under the ever-changing economic environment. Particular focus would go to the interactions among government, industry and universities in the national innovation system at a macro level, and entrepreneurship education at the institutional…

Restructuring: Imperatives and Opportunities for Academic Leaders.

ERIC Educational Resources Information Center

Gumport, Patricia J.

2001-01-01

Offers critical reflection on higher education's past, describing some macro trends affecting public higher education in the United States and the responses by public research universities in particular. Briefly considers how technological innovations may reshape the academic future, and concludes with suggestions for how campus leaders might…

Interfacing peripheral nerve with macro-sieve electrodes following spinal cord injury.

PubMed

Birenbaum, Nathan K; MacEwan, Matthew R; Ray, Wilson Z

2017-06-01

Macro-sieve electrodes were implanted in the sciatic nerve of five adult male Lewis rats following spinal cord injury to assess the ability of the macro-sieve electrode to interface regenerated peripheral nerve fibers post-spinal cord injury. Each spinal cord injury was performed via right lateral hemisection of the cord at the T 9-10 site. Five months post-implantation, the ability of the macro-sieve electrode to interface the regenerated nerve was assessed by stimulating through the macro-sieve electrode and recording both electromyography signals and evoked muscle force from distal musculature. Electromyography measurements were recorded from the tibialis anterior and gastrocnemius muscles, while evoked muscle force measurements were recorded from the tibialis anterior, extensor digitorum longus, and gastrocnemius muscles. The macro-sieve electrode and regenerated sciatic nerve were then explanted for histological evaluation. Successful sciatic nerve regeneration across the macro-sieve electrode interface following spinal cord injury was seen in all five animals. Recorded electromyography signals and muscle force recordings obtained through macro-sieve electrode stimulation confirm the ability of the macro-sieve electrode to successfully recruit distal musculature in this injury model. Taken together, these results demonstrate the macro-sieve electrode as a viable interface for peripheral nerve stimulation in the context of spinal cord injury.

Breast-implant texturing associated with delamination of capsular layers: A histological analysis of the double capsule phenomenon.

PubMed

Efanov, J I; Giot, J P; Fernandez, J; Danino, M A

2017-06-01

Macro-texturing of breast implants was developed with the double goal of improving implant stabilization within the breast cavity and decreasing the rate of capsular contractures. However, recent evidence suggests that double capsular formation, a potentially worrisome phenomenon associated with late seromas and biofilms, occurs with preponderance in macro-textured implants. Our objective was to analyze histologically different regions of double capsules to determine if they are more prone to mechanical movements. A prospective analysis including patients undergoing second-stage expander to definitive breast-implant reconstruction post-mastectomy was conducted after intraoperative identification of the double capsule phenomenon. Two samples were collected from each capsules around the implant, located centrally and laterally. The specimens were sent for histological analysis by the institution's pathologist. In total, 10 patients were identified intraoperatively with partial double capsule phenomenon. Among samples retrieved from the lateral aspect of the breast implant, all were associated with delamination and fractures in the collagen matrix of the double capsules. This phenomenon was not observed in any sample from the dome of the breast. Breast-implant macro-texturing plays an important role on delamination of capsules on lateral portions of the breast, which may have an etiologic role in double capsule formation. Manufacturing implants with macro-texturing on one side and smooth surface on the other could diminish mechanical shear forces responsible for these findings. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Ectopic osteogenesis and angiogenesis regulated by porous architecture of hydroxyapatite scaffolds with similar interconnecting structure in vivo

PubMed Central

Li, Jinyu; Zhi, Wei; Xu, Taotao; Shi, Feng; Duan, Ke; Wang, Jianxin; Mu, Yandong; Weng, Jie

2016-01-01

The macro-pore sizes of porous scaffold play a key role for regulating ectopic osteogenesis and angiogenesis but many researches ignored the influence of interconnection between macro-pores with different sizes. In order to accurately reveal the relationship between ectopic osteogenesis and macro-pore sizes in dorsal muscle and abdominal cavities of dogs, hydroxyapatite (HA) scaffolds with three different macro-pore sizes of 500–650, 750–900 and 1100–1250 µm were prepared via sugar spheres-leaching process, which also had similar interconnecting structure determined by keeping the d/s ratio of interconnecting window diameter to macro-pore size constant. The permeability test showed that the seepage flow of fluid through the porous scaffolds increased with the increase of macro-pore sizes. The cell growth in three scaffolds was not affected by the macro-pore sizes. The in vivo ectopic implantation results indicated that the macro-pore sizes of HA scaffolds with the similar interconnecting structure have impact not only the speed of osteogenesis and angiogenesis but also the space distribution of newly formed bone. The scaffold with macro-pore sizes of 750–900 µm exhibited much faster angiogenesis and osteogenesis, and much more uniformly distribution of new bone than those with other macro-pore sizes. This work illustrates the importance of a suitable macro-pore sizes in HA scaffolds with the similar interconnecting structure which provides the environment for ectopic osteogenesis and angiogenesis. PMID:27699059

Macro TSH in patients with subclinical hypothyroidism.

PubMed

Hattori, Naoki; Ishihara, Takashi; Yamagami, Keiko; Shimatsu, Akira

2015-12-01

TSH is a sensitive indicator of thyroid function. In subclinical hypothyroidism, however, serum TSH concentrations are elevated despite normal thyroid hormone levels, and macro TSH is one of the causes. This study aimed to clarify the prevalence and nature of macro TSH in patients with subclinical hypothyroidism. We conducted a 2-year cross-sectional observational study. We included 681 patients with subclinical hypothyroidism and 38 patients with overt hypothyroidism (controls). Macro TSH was screened by polyethylene glycol (PEG) method and analysed by gel filtration chromatography and bioassays. Among 681 serum samples, 117 exhibited PEG-precipitable TSH ratios greater than 75% (mean + 1·5 SD in controls) and were subjected to gel filtration chromatography. TSH was eluted at a position greater than 100 kDa in 11 patients with subclinical hypothyroidism (1·62%); these patients were diagnosed with macro TSH. The nature of macro TSH included eight anti-TSH autoantibodies of IgG class, two non-IgG-associated and one human anti-mouse antibody (HAMA). Macro TSH showed low bioactivity. Macro TSH was heterogeneous, but it is mostly comprised of TSH and anti-TSH autoantibodies. When PEG-precipitable TSH exceeds 90% in serum samples with TSH above 10 mU/l, clinicians should strongly suspect the presence of macro TSH and confirm it by gel chromatography. Because macro TSH exhibited low bioactivity, thyroid hormone replacement therapy may not be required in patients with subclinical hypothyroidism due to macro TSH except for those with high serum free TSH levels. © 2014 John Wiley & Sons Ltd.

Fixed forced detection for fast SPECT Monte-Carlo simulation

NASA Astrophysics Data System (ADS)

Cajgfinger, T.; Rit, S.; Létang, J. M.; Halty, A.; Sarrut, D.

2018-03-01

Monte-Carlo simulations of SPECT images are notoriously slow to converge due to the large ratio between the number of photons emitted and detected in the collimator. This work proposes a method to accelerate the simulations based on fixed forced detection (FFD) combined with an analytical response of the detector. FFD is based on a Monte-Carlo simulation but forces the detection of a photon in each detector pixel weighted by the probability of emission (or scattering) and transmission to this pixel. The method was evaluated with numerical phantoms and on patient images. We obtained differences with analog Monte Carlo lower than the statistical uncertainty. The overall computing time gain can reach up to five orders of magnitude. Source code and examples are available in the Gate V8.0 release.

Fixed forced detection for fast SPECT Monte-Carlo simulation.

PubMed

Cajgfinger, T; Rit, S; Létang, J M; Halty, A; Sarrut, D

2018-03-02

Monte-Carlo simulations of SPECT images are notoriously slow to converge due to the large ratio between the number of photons emitted and detected in the collimator. This work proposes a method to accelerate the simulations based on fixed forced detection (FFD) combined with an analytical response of the detector. FFD is based on a Monte-Carlo simulation but forces the detection of a photon in each detector pixel weighted by the probability of emission (or scattering) and transmission to this pixel. The method was evaluated with numerical phantoms and on patient images. We obtained differences with analog Monte Carlo lower than the statistical uncertainty. The overall computing time gain can reach up to five orders of magnitude. Source code and examples are available in the Gate V8.0 release.

Macro creatine kinase: determination and differentiation of two types by their activation energies

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

Stein, W.; Bohner, J.; Steinhart, R.

1982-01-01

Determination of the MB isoenzyme of creatine kinase in patients with acute myocardial infarction may be disturbed by the presence of macro creatine kinase. The relative molecular mass of this form of creatine kinase in human serum is at least threefold that of the ordinary enzyme, and it is more thermostable. Here we describe our method for determination of macro creatine kinases and an easy-to-perform test for differentiating two forms of macro creatine kinase, based on their distinct activation energies. The activation energies of serum enzymes are mostly in the range of 40-65 kJ/mol of substrate. Unlike normal cytoplasmatic creatinemore » kinases and IgG-linked CK-BB (macro creatine kinase type 1) a second form of macro creatine kinase (macro creatine kinase type 2) shows activation energies greater than 80 kJ/mol of substrate. The exact composition of macro creatine kinase type 2 is still unknown, but there is good reason to believe that it is of mitochondrial origin.« less

Response of jatropha on a clay soil to different concentrations of micronutrients

USDA-ARS?s Scientific Manuscript database

In recent years Jatropha curcas L. has emerged as a biofuel crop with potential for its production in marginal land with application of treated sewage water. Since this is a new crop for its profitable cultivation, additional research is needed to develop optimal management programs, including macro...

Subnational Opposition to Globalization

ERIC Educational Resources Information Center

Almeida, Paul

2012-01-01

Using a unique dataset on the geographic distribution of reported protest events from local sources, the study explains the variation in community-level mobilization in response to neoliberal reforms in two countries in the global periphery. Building on insights from macro, cross-national studies of protests related to market reforms, this article…

Teaching Engineering Ethics with Sustainability as Context

ERIC Educational Resources Information Center

Byrne, Edmond P.

2012-01-01

Purpose: The purpose of this paper is to ascertain the engagement and response of students to the teaching of engineering ethics incorporating a macro ethical framework whereby sustainability is viewed as context to professional practice. This involves incorporating a broader conception of engineering than is typically applied in conventional…

Biogenic reefs affect multiple components of intertidal soft-bottom benthic assemblages: the Lanice conchilega case study

NASA Astrophysics Data System (ADS)

De Smet, Bart; D'Hondt, An-Sofie; Verhelst, Pieterjan; Fournier, Jérôme; Godet, Laurent; Desroy, Nicolas; Rabaut, Marijn; Vincx, Magda; Vanaverbeke, Jan

2015-01-01

Biogenic reefs composed of the tube-building polychaete Lanice conchilega are important from a conservation point of view because they noticeably increase the biodiversity in otherwise species poor environments. However, up to now, little or no attention has been paid to the intertidal epi- and hyperbenthic communities associated with the reefs. Therefore, this is the first study which focuses on the effect of L. conchilega reefs on the entire bentho-pelagic community at two different locations. Environmental variables were measured and macro-, epi- and hyperbenthic communities were sampled within a L. conchilega reef and a control area at two locations in France: the bay of the Mont Saint-Michel (BMSM) and Boulogne-sur-Mer (Boulogne). The effect of the reef presence on the benthic community was studied with a 3-factor (Reef, Location and Period) Permanova. In addition, the relationship between the benthic community and the environmental variables was investigated using Distance-based linear models (DistLM). Most collected organisms were sampled in the reef area (macrobenthos: 91%, epibenthos: 81% and hyperbenthos: 78.5%) indicating that, independent of the location, the L. conchilega reefs positively affect all three associated benthic communities. However, the extent of the effect seems to be most pronounced for the macrobenthos and less distinct in case of the hyperbenthos. The macro-, and epibenthos are mainly structured by biotic variables (L. conchilega density and macrobenthic food availability respectively), while the hyperbenthos is rather structured by environmental variables. In general, L. conchilega reefs do not only affect abundances and diversity but they substantially steer the structure of the intertidal benthic sandy beach ecosystem.

Macro Pixel ASIC (MPA): the readout ASIC for the pixel-strip (PS) module of the CMS outer tracker at HL-LHC

NASA Astrophysics Data System (ADS)

Ceresa, D.; Marchioro, A.; Kloukinas, K.; Kaplon, J.; Bialas, W.; Re, V.; Traversi, G.; Gaioni, L.; Ratti, L.

2014-11-01

The CMS tracker at HL-LHC is required to provide prompt information on particles with high transverse momentum to the central Level 1 trigger. For this purpose, the innermost part of the outer tracker is based on a combination of a pixelated sensor with a short strip sensor, the so-called Pixel-Strip module (PS). The readout of these sensors is carried out by distinct ASICs, the Strip Sensor ASIC (SSA), for the strip layer, and the Macro Pixel ASIC (MPA) for the pixel layer. The processing of the data directly on the front-end module represents a design challenge due to the large data volume (30720 pixels and 1920 strips per module) and the limited power budget. This is the reason why several studies have been carried out to find the best compromise between ASICs performance and power consumption. This paper describes the current status of the MPA ASIC development where the logic for generating prompt information on particles with high transverse momentum is implemented. An overview of the readout method is presented with particular attention on the cluster reduction, position encoding and momentum discrimination logic. Concerning the architectural studies, a software test bench capable of reading physics Monte-Carlo generated events has been developed and used to validate the MPA design and to evaluate the MPA performance. The MPA-Light is scheduled to be submitted for fabrication this year and will include the full analog functions and a part of the digital logic of the final version in order to qualify the chosen VLSI technology for the analog front-end, the module assembly and the low voltage digital supply.

Neutron matter with Quantum Monte Carlo: chiral 3N forces and static response

DOE PAGES

Buraczynski, M.; Gandolfi, S.; Gezerlis, A.; ...

2016-03-14

Neutron matter is related to the physics of neutron stars and that of neutron-rich nuclei. Moreover, Quantum Monte Carlo (QMC) methods offer a unique way of solving the many-body problem non-perturbatively, providing feedback on features of nuclear interactions and addressing scenarios that are inaccessible to other approaches. Our contribution goes over two recent accomplishments in the theory of neutron matter: a) the fusing of QMC with chiral effective field theory interactions, focusing on local chiral 3N forces, and b) the first attempt to find an ab initio solution to the problem of static response.

The asymmetric effect of coal price on the China's macro economy using NARDL model

NASA Astrophysics Data System (ADS)

Hou, J. C.; Yang, M. C.

2016-08-01

The present work endeavors to explore the asymmetric effect of coal price on the China's macro economy by applying nonlinear autoregressive distributed lag (NARDL) model for the period of January 2005 to June 2015. The obtained results indicate that the coal price has a strong asymmetric effect on China's macro economy in the long-run. Namely one percent increase in coal price leads to 0.6194 percent of the China's macro economy increase; and while the coal price is reduces by 1 percent, the China's macro economy will decrease by 0.008 percent. These data indicate that when coal price rises, the effect on China's macro economy is far greater than the price decline. In the short-run, coal price fluctuation has a positive effect on the China's macro economy.

Teaching Conversations with the XDS Sigma 7. Systems Description.

ERIC Educational Resources Information Center

Bork, Alfred M.; Mosmann, Charles

Some computers permit conventional programing languages to be extended by the use of macro-instructions, a sophisticated programing tool which is especially useful in writing instructional dialogs. Macro-instructions (or "macro's") are complex commands defined in terms of the machine language or other macro-instructions. Like terms in…

Trade Space Analysis: Rotational Analyst Research Project

DTIC Science & Technology

2015-09-01

POM Program Objective Memoranda PM Program Manager RFP Request for Proposal ROM Rough Order Magnitude RSM Response Surface Method RSE ...response surface method (RSM) / response surface equations ( RSEs ) as surrogate models. It uses the RSEs with Monte Carlo simulation to quantitatively

[Municipal public health spending in the state of Pernambuco, Brazil, from 2000 to 2007].

PubMed

Espírito Santo, Antônio Carlos Gomes do; Fernando, Virgínia Conceição Nascimento; Bezerra, Adriana Falangola Benjamin

2012-04-01

In order to assess the impact of macro-political measures implemented in the latter half of the 1990s on the increase in public spending on health and the possible reduction in allocation inequity, a descriptive, quantitative, cross-sectional study was carried out involving 184 municipalities in the state of Pernambuco, Brazil. Data from the Public Health Budget Information System was used, with the selected indicator being spending on health per inhabitant under the responsibility of the municipality. The correlations of this variable with the municipal Human Development Index, population size and value of the municipal budget per capita were analyzed. It was seen that, although the mean increase in municipal spending on health is 190.76%, the value per capita has remained relatively low - at around R$183.79 - which is below the national and macro-regional averages. Both spending on health per capita and growth percentages are distributed irregularly among health regions as well as among municipalities within a single region. In conclusion, there is marked allocation inequity among municipalities with regard to the distribution of public resources for health, despite the macro-political measures adopted to reduce this inequity.

[Community structure of soil fauna in Eucalyptus grandis plantations at different slope locations].

PubMed

Zhao, Yu; Zhong, Yu; Zhang, Jian; Yang, Wan-qin

2010-09-01

To understand the effects of slope location on the community structure of soil fauna in Eucalyptus grandis plantation, an investigation was made on the soil fauna in 3 E. grandis plantations at different slope locations in the hilly area of Sichuan Province from January to October 2009. A total of 39,2762 individuals were observed, belonging to 146 groups, 7 phyla, 16 classes, and 31 orders. The community composition, trophic group, diversity, and seasonal dynamics of soil fauna in the plantations all varied with slope. The abundance of macro-fauna, xeric meso- and micro-fauna, saprophagous macro-fauna, and omnivorous xeric meso- and micro-fauna increased with the decrease of slope, indicating that soil fauna had sensitive responses to the soil environmental factors affected by slope. Significant differences in the diversity of soil saprophagous macro-fauna and hygrophilous meso- and micro-fauna were observed at different slope locations, suggesting that these two faunal groups could be used as the indicators of the habitat heterogeneity of E. grandis plantations at different slope. Overall, slope location had definite effects on the community structure and distribution of soil fauna in the E. grandis plantations, but the effects were not statistically significant.

Macro policy responses to oil booms and busts in the United Arab Emirates

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

Al-Mutawa, A.K.

1991-01-01

The effects of oil shocks and macro policy changes in the United Arab Emirates are analyzed. A theoretical model is developed within the framework of the Dutch Disease literature. It contains four unique features that are applicable to the United Arab Emirates' economy. There are: (1) the presence of a large foreign labor force; (2) OPEC's oil export quotas; (3) the division of oil profits; and (4) the important role of government expenditures. The model is then used to examine the welfare effects of the above-mentioned shocks. An econometric model is then specified that conforms to the analytical model. Inmore » the econometric model the method of principal components' is applied owing to the undersized sample data. The principal components methodology is used in both the identification testing and the estimation of the structural equations. The oil and macro policy shocks are then simulated. The simulation results show that an oil-quantity boom leads to a higher welfare gain than an oil-price boom. Under certain circumstances, this finding is also confirmed by the comparative statistics that follow from the analytical model.« less

Adjustment Costs, Firm Responses, and Micro vs. Macro Labor Supply Elasticities: Evidence from Danish Tax Records*

PubMed Central

Chetty, Raj; Friedman, John N.; Olsen, Tore; Pistaferri, Luigi

2011-01-01

We show that the effects of taxes on labor supply are shaped by interactions between adjustment costs for workers and hours constraints set by firms. We develop a model in which firms post job offers characterized by an hours requirement and workers pay search costs to find jobs. We present evidence supporting three predictions of this model by analyzing bunching at kinks using Danish tax records. First, larger kinks generate larger taxable income elasticities. Second, kinks that apply to a larger group of workers generate larger elasticities. Third, the distribution of job offers is tailored to match workers' aggregate tax preferences in equilibrium. Our results suggest that macro elasticities may be substantially larger than the estimates obtained using standard microeconometric methods. PMID:21836746

Using Data Augmentation and Markov Chain Monte Carlo for the Estimation of Unfolding Response Models

ERIC Educational Resources Information Center

Johnson, Matthew S.; Junker, Brian W.

2003-01-01

Unfolding response models, a class of item response theory (IRT) models that assume a unimodal item response function (IRF), are often used for the measurement of attitudes. Verhelst and Verstralen (1993)and Andrich and Luo (1993) independently developed unfolding response models by relating the observed responses to a more common monotone IRT…

Challenges to Bridging Field and Classroom Instruction: Exploring Field Instructors' Perspectives on Macro Practice

ERIC Educational Resources Information Center

Mehrotra, Gita R.; Tecle, Aster S.; Ha, An Thi; Ghneim, Staci; Gringeri, Christina

2018-01-01

Field education and macro practice have been highlighted as central educational domains in social work education; however, little scholarship has looked at how macro social work practice competencies have been integrated into field-based learning. This exploratory study aimed to gain perspectives from field instructors regarding macro social work…

Spreadsheet macros for coloring sequence alignments.

PubMed

Haygood, M G

1993-12-01

This article describes a set of Microsoft Excel macros designed to color amino acid and nucleotide sequence alignments for review and preparation of visual aids. The colored alignments can then be modified to emphasize features of interest. Procedures for importing and coloring sequences are described. The macro file adds a new menu to the menu bar containing sequence-related commands to enable users unfamiliar with Excel to use the macros more readily. The macros were designed for use with Macintosh computers but will also run with the DOS version of Excel.

LARCMACS: A TEX macro set for typesetting NASA reports

NASA Technical Reports Server (NTRS)

Woessner, Linda H.; Mccaskill, Mary K.

1988-01-01

This LARCMACS user's manual describes the February 1988 version of LARCMACS, the TEX macro set used by the Technical Editing Branch (TEB) at NASA Langley Research Center. These macros were developed by the authors to facilitate the typesetting of NASA formal reports. They are also useful, however, for informal NASA reports and other technical documents such as meeting papers. LARCMACS are distributed by TEB for the convenience of the Langley TEX user community. LARCMACS contain macros for obtaining the standard double-column format for NASA reports, for typesetting tables in the ruled format traditional in NASA reports, and for typesetting difficult mathematical expressions. Each macro is described and numerous examples are included. Definitions of the LARCMACS macros are also included.

Linking Resilience and Transformation as Micro- and Macro Adaptation

NASA Astrophysics Data System (ADS)

Friedman, E.; Breitzer, R.; Solecki, W. D.

2017-12-01

The concept of resiliency within climate adaptation planning and practice is widespread, but in some ways it has begun to suffer from its own success. While resiliency provides a valuable frame for understanding the conditions and opportunities for localized responses to increasing climate risks, the concept's ubiquitous use leads to it being applied to often conflicting policy agendas, which can mask or limit the capacity to connect efforts focused on near term risk to longer term and emergent climate threats in communities. These challenges are particularly evident in the context of extreme events and in the post extreme event policy windows. To overcome these issues and take advantage of the post-event policy window, the NOAA RISA Climate Change Risk in the Urban Northeast (CCRUN) project has been developing two specific, "boutique", policy tools. These include the PELT (Post-event learning toolkit) and MART (Macro-adaptation Resilience toolkit) toolkits. Embedded in these toolkits are two approaches to small scale strategies often associated with near term action (i.e., micro-adaptation) and large scale strategies associated with broad longer term needs (i.e., macro-adaptation). In this paper, these two approaches - micro and macro adaptation - are theoretically defined and presented in practice through the beta-testing of the PELT and MART toolkits. Most importantly, we illustrate how the theoretical links between resiliency and transformation can be operationalized through the use of these approaches, and how these approaches can be implemented in everyday risk management practice. We present our work through selected case studies in the Northeast US region, specifically in Jamaica Bay, New York, and Eastwick neighborhood in Philadelphia.

Power analysis as a tool to identify statistically informative indicators for monitoring coral reef disturbances.

PubMed

Van Wynsberge, Simon; Gilbert, Antoine; Guillemot, Nicolas; Heintz, Tom; Tremblay-Boyer, Laura

2017-07-01

Extensive biological field surveys are costly and time consuming. To optimize sampling and ensure regular monitoring on the long term, identifying informative indicators of anthropogenic disturbances is a priority. In this study, we used 1800 candidate indicators by combining metrics measured from coral, fish, and macro-invertebrate assemblages surveyed from 2006 to 2012 in the vicinity of an ongoing mining project in the Voh-Koné-Pouembout lagoon, New Caledonia. We performed a power analysis to identify a subset of indicators which would best discriminate temporal changes due to a simulated chronic anthropogenic impact. Only 4% of tested indicators were likely to detect a 10% annual decrease of values with sufficient power (>0.80). Corals generally exerted higher statistical power than macro-invertebrates and fishes because of lower natural variability and higher occurrence. For the same reasons, higher taxonomic ranks provided higher power than lower taxonomic ranks. Nevertheless, a number of families of common sedentary or sessile macro-invertebrates and fishes also performed well in detecting changes: Echinometridae, Isognomidae, Muricidae, Tridacninae, Arcidae, and Turbinidae for macro-invertebrates and Pomacentridae, Labridae, and Chaetodontidae for fishes. Interestingly, these families did not provide high power in all geomorphological strata, suggesting that the ability of indicators in detecting anthropogenic impacts was closely linked to reef geomorphology. This study provides a first operational step toward identifying statistically relevant indicators of anthropogenic disturbances in New Caledonia's coral reefs, which can be useful in similar tropical reef ecosystems where little information is available regarding the responses of ecological indicators to anthropogenic disturbances.

Emergency Planning Guidelines for Campus Health Services: An All-Hazards Approach

ERIC Educational Resources Information Center

Journal of American College Health, 2011

2011-01-01

This document, written collaboratively by members of ACHA's Emerging Public Health Threats and Emergency Response Coalition and Campus Safety and Violence Coalition, is designed to assist members of the college health community in planning for emergencies using an all-hazards approach. Its perspective is both macro and micro, beginning with a…

Fertilizer recommendations for switchgrass: Quantifying economic effects on quality and yield

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum L.) is a native, perennial warm season grass that is suited for biomass production for conversion to renewable fuels as well as feed production on marginal soils. Yield responses to macro nutrients of N, P and K, have shown N to be the major driver for capturing yield p...

Responding to Global Shifts: Meta-Practice as a Relevant Social Work Practice Paradigm

ERIC Educational Resources Information Center

Grise-Owens, Erlene; Miller, J. Jay; Owens, Larry W.

2014-01-01

In response to increasing global changes, this article proposes that social work education add meta-practice to traditional micro-, mezzo-, and macro-practice curriculum areas. Drawing on pertinent literature, the authors conceptualize meta-practice as a necessary paradigm shift for competent and relevant social work practice. Further, the authors…

Linking species richness, biodiversity and ecosystem function in soil system

Treesearch

David C. Coleman; William B. Whitman

2004-01-01

Soils are the central organizing entities in terrestrial ecosystem and possess extremely diverse prokaryotic and eukaryotic biota. They are physically and chemically complex, with micro- and macro-aggregates embedded within a solid, liquid and gaseous matrix that is continually changing in response to natural and human-induced perturbations. Recent advances in...

Mantle displays of freshwater mussels elicit attacks from fish

Treesearch

Wendell R. Haag; Melvin L. Warren

1999-01-01

Gravid females of some North American freshwater mussel species (Bivalvia: Unionidae) display highly modified mantle margins and other reproductive structures which mimic small fish, terrestrial insects, or aquatic macro-invertebrates. The authors report the responses of fish to these lures, based on the results of laboratory encounters between the following pairs of...

Testing Some Notions of the Fact/Opinion Distinction in Libel.

ERIC Educational Resources Information Center

Cohen, Jeremy; And Others

A study of reader response to newspaper articles in a defamatory context tested: (1) the judicial assumption that the macro-environment in which statements appear is important to a reader's distinguishing between fact and opinion; (2) the possibility that a byline may influence a reader's characterization of statements; and (3) the idea that…

Nocturnal insect availability in bottomland hardwood forests managed for wildlife in the Mississippi Alluvial Valley

USGS Publications Warehouse

Loraine Ketzler,; Christopher Comer,; Twedt, Daniel J.

2017-01-01

Silviculture used to alter forest structure and thereby enhance wildlife habitat has been advocated for bottomland hardwood forest management on public conservation lands in the Mississippi Alluvial Valley. Although some songbirds respond positively to these management actions to attain desired forest conditions for wildlife, the response of other species, is largely unknown. Nocturnal insects are a primary prey base for bats, thereby influencing trophic interactions within hardwood forests. To better understand how silviculture influences insect availability for bats, we conducted vegetation surveys and sampled insect biomass within silviculturally treated bottomland hardwood forest stands. We used passive blacklight traps to capture nocturnal flying insects in 64 treated and 64 untreated reference stands, located on 15 public conservation areas in Arkansas, Louisiana, and Mississippi. Dead wood and silvicultural treatments were positively associated with greater biomass of macro-Lepidoptera, macro-Coleoptera, and all insect taxa combined. Biomass of micro-Lepidoptera was negatively associated with silvicultural treatment but comprised only a small proportion of total biomass. Understanding the response of nocturnal insects to wildlife-forestry silviculture provides insight for prescribed silvicultural management affecting bat species.

Micromechanics-Based Inelastic Finite Element Analysis Accomplished Via Seamless Integration of MAC/GMC

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Trowbridge, D.

2001-01-01

A critical issue in the micromechanics-based analysis of composite structures becomes the availability of a computationally efficient homogenization technique: one that is 1) Capable of handling the sophisticated, physically based, viscoelastoplastic constitutive and life models for each constituent; 2) Able to generate accurate displacement and stress fields at both the macro and the micro levels; 3) Compatible with the finite element method. The Generalized Method of Cells (GMC) developed by Paley and Aboudi is one such micromechanical model that has been shown to predict accurately the overall macro behavior of various types of composites given the required constituent properties. Specifically, the method provides "closed-form" expressions for the macroscopic composite response in terms of the properties, size, shape, distribution, and response of the individual constituents or phases that make up the material. Furthermore, expressions relating the internal stress and strain fields in the individual constituents in terms of the macroscopically applied stresses and strains are available through strain or stress concentration matrices. These expressions make possible the investigation of failure processes at the microscopic level at each step of an applied load history.

On the coupling of nonlinear macro-fiber composite piezoelectric cantilever dynamics with hydrodynamic loads

NASA Astrophysics Data System (ADS)

Tan, D.; Erturk, A.

2018-03-01

For bio-inspired, fish-like robotic propulsion, the Macro-Fiber Composite (MFC) piezoelectric technology offers noiseless actuation with a balance between actuation force and velocity response. However, internal nonlinear- ities within the MFCs, such as piezoelectric softening, geometric hardening, inertial softening, and nonlinear dissipation, couple with the hydrodynamic loading on the structure from the surrounding fluid. In the present work, we explore nonlinear actuation of MFC cantilevers underwater and develop a mathematical framework for modeling and analysis. In vacuo resonant actuation experiments are conducted for a set of MFC cantilevers of varying length to width aspect ratios to validate the structural model in the absence of fluid loading. These MFC cantilevers are then subjected to underwater resonant actuation experiments, and model simulations are compared with nonlinear experimental frequency response functions. It is observed that semi-empirical hydro- dynamic loads obtained from quasilinear experiments have to be modified to account for amplitude dependent added mass, and additional nonlinear hydrodynamic effects might be present, yielding qualitative differences in the resulting underwater frequency respones curves with increased excitation amplitude.

SU-E-T-391: Assessment and Elimination of the Angular Dependence of the Response of the NanoDot OSLD System in MV Beams

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

Lehmann, J; University of Sydney, Sydney; RMIT University, Melbourne

2014-06-01

Purpose: Assess the angular dependence of the nanoDot OSLD system in MV X-ray beams at depths and mitigate this dependence for measurements in phantoms. Methods: Measurements for 6 MV photons at 3 cm and 10 cm depth and Monte Carlo simulations were performed. Two special holders were designed which allow a nanoDot dosimeter to be rotated around the center of its sensitive volume (5 mm diameter disk). The first holder positions the dosimeter disk perpendicular to the beam (en-face). It then rotates until the disk is parallel with the beam (edge on). This is referred to as Setup 1. Themore » second holder positions the disk parallel to the beam (edge on) for all angles (Setup 2). Monte Carlo simulations using GEANT4 considered detector and housing in detail based on microCT data. Results: An average drop in response by 1.4±0.7% (measurement) and 2.1±0.3% (Monte Carlo) for the 90° orientation compared to 0° was found for Setup 1. Monte Carlo simulations also showed a strong dependence of the effect on the composition of the sensitive layer. Assuming 100% active material (Al??O??) results in a 7% drop in response for 90° compared to 0°. Assuming the layer to be completely water, results in a flat response (within simulation uncertainty of about 1%). For Setup 2, measurements and Monte Carlo simulations found the angular dependence of the dosimeter to be below 1% and within the measurement uncertainty. Conclusion: The nanoDot dosimeter system exhibits a small angular dependence off approximately 2%. Changing the orientation of the dosimeter so that a coplanar beam arrangement always hits the detector material edge on reduces the angular dependence to within the measurement uncertainty of about 1%. This makes the dosimeter more attractive for phantom based clinical measurements and audits with multiple coplanar beams. The Australian Clinical Dosimetry Service is a joint initiative between the Australian Department of Health and the Australian Radiation Protection and Nuclear Safety Agency.« less

The financial crisis and global health: the International Monetary Fund's (IMF) policy response.

PubMed

Ruckert, Arne; Labonté, Ronald

2013-09-01

In this article, we interrogate the policy response of the International Monetary Fund (IMF) to the global financial crisis, and discuss the likely global health implications, especially in low-income countries. In doing so, we ask if the IMF has meaningfully loosened its fiscal deficit targets in light of the economic challenges posed by the financial crisis and adjusted its macro-economic policy advice to this new reality; or has the rhetoric of counter-cyclical spending failed to translate into additional fiscal space for IMF loan-recipient countries, with negative health consequences? To answer these questions, we assess several post-crisis IMF lending agreements with countries requiring financial assistance, and draw upon recent academic studies and civil society reports examining policy conditionalities still being prescribed by the IMF. We also reference recent studies examining the health impacts of these conditionalities. We demonstrate that while the IMF has been somewhat more flexible in its crisis response than in previous episodes of financial upheaval, there has been no meaningful rethinking in the application of dominant neoliberal macro-economic policies. After showing some flexibility in the initial crisis response, the IMF is pushing for excessive contraction in most low and middle-income countries. We conclude that there remains a wide gap between the rhetoric and the reality of the IMF's policy and programming advice, with negative implications for global health.

Probabilistic Thermal Analysis During Mars Reconnaissance Orbiter Aerobraking

NASA Technical Reports Server (NTRS)

Dec, John A.

2007-01-01

A method for performing a probabilistic thermal analysis during aerobraking has been developed. The analysis is performed on the Mars Reconnaissance Orbiter solar array during aerobraking. The methodology makes use of a response surface model derived from a more complex finite element thermal model of the solar array. The response surface is a quadratic equation which calculates the peak temperature for a given orbit drag pass at a specific location on the solar panel. Five different response surface equations are used, one of which predicts the overall maximum solar panel temperature, and the remaining four predict the temperatures of the solar panel thermal sensors. The variables used to define the response surface can be characterized as either environmental, material property, or modeling variables. Response surface variables are statistically varied in a Monte Carlo simulation. The Monte Carlo simulation produces mean temperatures and 3 sigma bounds as well as the probability of exceeding the designated flight allowable temperature for a given orbit. Response surface temperature predictions are compared with the Mars Reconnaissance Orbiter flight temperature data.

In-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in bearing steels

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

Voothaluru, Rohit; Bedekar, Vikram; Xie, Qingge

This work integrates in-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in high carbon bearing steels. The presence of a kinematically metastable retained austenite in bearing steels can significantly affect the macro-mechanical and micro-mechanical material response. Mechanical characterization of metastable austenite is a critical component in accurately capturing the micro-mechanical behavior under typical application loads. Traditional mechanical characterization techniques are unable to discretely quantify the micro-mechanical response of the austenite, and as a result, the computational predictions rely heavily on trial and error or qualitative descriptions of the austenite phase. Inmore » order to overcome this, in the present work, we use in-situ neutron diffraction of a uniaxial tension test of an A485 Grade 1 bearing steel specimen. The mechanical response determined from the neutron diffraction analysis was incorporated into a hybrid crystal plasticity finite element model that accounts for the martensite's crystal plasticity and the stress-assisted transformation from austenite to martensite in bearing steels. Here, the modeling response was used to estimate the single crystal elastic constants of the austenite and martensite phases. Finally, the results show that using in-situ neutron diffraction, coupled with a crystal plasticity model, can successfully predict both the micro-mechanical and macro-mechanical responses of bearing steels while accounting for the martensitic transformation of the retained austenite.« less

In-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in bearing steels

DOE PAGES

Voothaluru, Rohit; Bedekar, Vikram; Xie, Qingge; ...

2018-11-21

This work integrates in-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in high carbon bearing steels. The presence of a kinematically metastable retained austenite in bearing steels can significantly affect the macro-mechanical and micro-mechanical material response. Mechanical characterization of metastable austenite is a critical component in accurately capturing the micro-mechanical behavior under typical application loads. Traditional mechanical characterization techniques are unable to discretely quantify the micro-mechanical response of the austenite, and as a result, the computational predictions rely heavily on trial and error or qualitative descriptions of the austenite phase. Inmore » order to overcome this, in the present work, we use in-situ neutron diffraction of a uniaxial tension test of an A485 Grade 1 bearing steel specimen. The mechanical response determined from the neutron diffraction analysis was incorporated into a hybrid crystal plasticity finite element model that accounts for the martensite's crystal plasticity and the stress-assisted transformation from austenite to martensite in bearing steels. Here, the modeling response was used to estimate the single crystal elastic constants of the austenite and martensite phases. Finally, the results show that using in-situ neutron diffraction, coupled with a crystal plasticity model, can successfully predict both the micro-mechanical and macro-mechanical responses of bearing steels while accounting for the martensitic transformation of the retained austenite.« less

Studying neighborhood crime across different macro spatial scales: The case of robbery in 4 cities.

PubMed

Hipp, John R; Wo, James C; Kim, Young-An

2017-11-01

Whereas there is a burgeoning literature focusing on the spatial distribution of crime events across neighborhoods or micro-geographic units in a specific city, the present study expands this line of research by selecting four cities that vary across two macro-spatial dimensions: population in the micro-environment, and population in the broader macro-environment. We assess the relationship between measures constructed at different spatial scales and robbery rates in blocks in four cities: 1) San Francisco (high in micro- and macro-environment population); 2) Honolulu (high in micro- but low in macro-environment population); 3) Los Angeles (low in micro- but high in macro-environment population); 4) Sacramento (low in micro- and macro-environment population). Whereas the socio-demographic characteristics of residents further than ½ mile away do not impact robbery rates, the number of people up to 2.5 miles away are related to robbery rates, especially in the two cities with smaller micro-environment population, implying a larger spatial scale than is often considered. The results show that coefficient estimates differ somewhat more between cities differing in micro-environment population compared to those differing based on macro-environment population. It is therefore necessary to consider the broader macro-environment even when focusing on the level of crime across neighborhoods or micro-geographic units within an area. Copyright © 2017 Elsevier Inc. All rights reserved.

Adsorption study of a macro-RAFT agent onto SiO2-coated Gd2O3:Eu3+ nanorods: Requirements and limitations

NASA Astrophysics Data System (ADS)

Zou, Hua; Melro, Liliana; de Camargo Chaparro, Thaissa; de Souza Filho, Isnaldi Rodrigues; Ananias, Duarte; Bourgeat-Lami, Elodie; dos Santos, Amilton Martins; Barros-Timmons, Ana

2017-02-01

The use of a macromolecular RAFT (macro-RAFT) agent to encapsulate anisotropic nano-objects via emulsion polymerization is an emerging route to prepare polymer/inorganic colloidal nanocomposites. However, a number of requirements have to be fulfilled. This work aims at highlighting the effects of the preparative procedure and dispersion method on the amount of macro-RAFT agent adsorbed onto SiO2-coated Gd2O3:Eu3+ nanorods. The adsorption of macro-RAFT agent was studied using the depletion method with UV-vis spectrophotometry. Measurements were performed at a fixed concentration of nanorods and varying concentrations of the macro-RAFT agent in aqueous dispersion at room temperature. The adsorption isotherms showed that for the same initial macro-RAFT agent concentration, the highest adsorption capacity of the macro-RAFT agent on nanorods was usually achieved for non-calcined thin SiO2-coated nanorods under mild bath sonication.

Filtered cathodic arc deposition apparatus and method

DOEpatents

Krauss, Alan R.

1999-01-01

A filtered cathodic arc deposition method and apparatus for the production of highly dense, wear resistant coatings which are free from macro particles. The filtered cathodic arc deposition apparatus includes a cross shaped vacuum chamber which houses a cathode target having an evaporable surface comprised of the coating material, means for generating a stream of plasma, means for generating a transverse magnetic field, and a macro particle deflector. The transverse magnetic field bends the generated stream of plasma in the direction of a substrate. Macro particles are effectively filtered from the stream of plasma by traveling, unaffected by the transverse magnetic field, along the initial path of the plasma stream to a macro particle deflector. The macro particle deflector has a preformed surface which deflects macro particles away from the substrate.

Reduction in soil aggregation in response to dust emission processes

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2016-09-01

Dust emission by aeolian (wind) soil erosion depends on the topsoil properties of the source area, especially on the nature of the aggregates where most dust particles are held. Although the key role of soil aggregates in dust emission, the response of soil aggregation to aeolian processes and its implications for dust emission remain unknown. This study focuses on aggregate size distribution (ASD) analyses before and after in-situ aeolian experiments in semiarid loess soils that are associated with dust emission. Wind tunnel simulations show that particulate matter (PM) emission and saltation rates depend on the initial ASD and shear velocity. Under all initial ASD conditions, the content of saltator-sized aggregates (63-250 μm) increased by 10-34% due to erosion of macro-aggregates (> 500 μm), resulting in a higher size ratio (SR) between the saltators and macro-aggregates following the aeolian erosion. The results revealed that the saltator production increases significantly for soils that are subjected to short-term (anthropogenic) disturbance of the topsoil. The findings highlight a decrease in soil aggregation for all initial ASD's in response to aeolian erosion, and consequently its influence on the dust emission potential. Changes in ASD should be considered as a key parameter in dust emission models of complex surfaces.

Experimental characterization and macro-modeling of mechanical strength of multi-sheets and multi-materials spot welds under pure and mixed modes I and II

NASA Astrophysics Data System (ADS)

Chtourou, Rim; Haugou, Gregory; Leconte, Nicolas; Zouari, Bassem; Chaari, Fahmi; Markiewicz, Eric

2015-09-01

Resistance Spot Welding (RSW) of multiple sheets with multiple materials are increasingly realized in the automotive industry. The mechanical strength of such new generation of spot welded assemblies is not that much dealt with. This is true in particular for experiments dedicated to investigate the mechanical strength of spot weld made by multi sheets of different grades, and their macro modeling in structural computations. Indeed, the most published studies are limited to two sheet assemblies. Therefore, in the first part of this work an advanced experimental set-up with a reduced mass is proposed to characterize the quasi-static and dynamic mechanical behavior and rupture of spot weld made by several sheets of different grades. The proposed device is based on Arcan test, the plates contribution in the global response is, thus, reduced. Loading modes I/II are, therefore, combined and well controlled. In the second part a simplified spot weld connector element (macroscopic modeling) is proposed to describe the nonlinear response and rupture of this new generation of spot welded assemblies. The weld connector model involves several parameters to be set. The remaining parameters are finally identified through a reverse engineering approach using mechanical responses of experimental tests presented in the first part of this work.

Simulation of argon response and light detection in the DarkSide-50 dual phase TPC

NASA Astrophysics Data System (ADS)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Asner, D. M.; Back, H. O.; Biery, K.; Bocci, V.; Bonfini, G.; Bonivento, W.; Bossa, M.; Bottino, B.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Caravati, M.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cataudella, V.; Cavalcante, P.; Chepurnov, A.; Cicalò, C.; Cocco, A. G.; Covone, G.; D'Angelo, D.; D'Incecco, M.; Davini, S.; de Candia, A.; De Cecco, S.; De Deo, M.; De Filippis, G.; De Vincenzi, M.; Derbin, A. V.; De Rosa, G.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Dionisi, C.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Giagu, S.; Giganti, C.; Giovanetti, G. K.; Goretti, A. M.; Granato, F.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K.; Hughes, D.; Humble, P.; Hungerford, E. V.; Ianni, An.; James, I.; Johnson, T. N.; Keeter, K.; Kendziora, C. L.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Loer, B.; Longo, G.; Ma, Y.; Machado, A. A.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Martoff, C. J.; Meyers, P. D.; Milincic, R.; Monte, A.; Mount, B. J.; Muratova, V. N.; Musico, P.; Napolitano, J.; Navrer Agasson, A.; Oleinik, A.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Pelczar, K.; Pelliccia, N.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Razeti, M.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Rescigno, M.; Riffard, Q.; Romani, A.; Rossi, B.; Rossi, N.; Sablone, D.; Sands, W.; Sanfilippo, S.; Savarese, C.; Schlitzer, B.; Segreto, E.; Semenov, D. A.; Singh, P. N.; Skorokhvatov, M. D.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Verducci, M.; Vishneva, A.; Vogelaar, B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Westerdale, S.; Wilhelmi, J.; Wojcik, M. M.; Xiang, X.; Xiao, X.; Yang, C.; Ye, Z.; Zhu, C.; Zuzel, G.

2017-10-01

A Geant4-based Monte Carlo package named G4DS has been developed to simulate the response of DarkSide-50, an experiment operating since 2013 at LNGS, designed to detect WIMP interactions in liquid argon. In the process of WIMP searches, DarkSide-50 has achieved two fundamental milestones: the rejection of electron recoil background with a power of ~107, using the pulse shape discrimination technique, and the measurement of the residual 39Ar contamination in underground argon, ~3 orders of magnitude lower with respect to atmospheric argon. These results rely on the accurate simulation of the detector response to the liquid argon scintillation, its ionization, and electron-ion recombination processes. This work provides a complete overview of the DarkSide Monte Carlo and of its performance, with a particular focus on PARIS, the custom-made liquid argon response model.

A collision history-based approach to Sensitivity/Perturbation calculations in the continuous energy Monte Carlo code SERPENT

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

Giuseppe Palmiotti

In this work, the implementation of a collision history-based approach to sensitivity/perturbation calculations in the Monte Carlo code SERPENT is discussed. The proposed methods allow the calculation of the eects of nuclear data perturbation on several response functions: the eective multiplication factor, reaction rate ratios and bilinear ratios (e.g., eective kinetics parameters). SERPENT results are compared to ERANOS and TSUNAMI Generalized Perturbation Theory calculations for two fast metallic systems and for a PWR pin-cell benchmark. New methods for the calculation of sensitivities to angular scattering distributions are also presented, which adopts fully continuous (in energy and angle) Monte Carlo estimators.

Quantifying causal emergence shows that macro can beat micro.

PubMed

Hoel, Erik P; Albantakis, Larissa; Tononi, Giulio

2013-12-03

Causal interactions within complex systems can be analyzed at multiple spatial and temporal scales. For example, the brain can be analyzed at the level of neurons, neuronal groups, and areas, over tens, hundreds, or thousands of milliseconds. It is widely assumed that, once a micro level is fixed, macro levels are fixed too, a relation called supervenience. It is also assumed that, although macro descriptions may be convenient, only the micro level is causally complete, because it includes every detail, thus leaving no room for causation at the macro level. However, this assumption can only be evaluated under a proper measure of causation. Here, we use a measure [effective information (EI)] that depends on both the effectiveness of a system's mechanisms and the size of its state space: EI is higher the more the mechanisms constrain the system's possible past and future states. By measuring EI at micro and macro levels in simple systems whose micro mechanisms are fixed, we show that for certain causal architectures EI can peak at a macro level in space and/or time. This happens when coarse-grained macro mechanisms are more effective (more deterministic and/or less degenerate) than the underlying micro mechanisms, to an extent that overcomes the smaller state space. Thus, although the macro level supervenes upon the micro, it can supersede it causally, leading to genuine causal emergence--the gain in EI when moving from a micro to a macro level of analysis.

Occurrence and Distribution of Ordinary High Water Mark (OHWM) Indicators in Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States

DTIC Science & Technology

2014-08-01

1 Common hydrogeomorphic units that form in stream systems in response to spatially and temporally varying hydrologic and geomorphic processes... geomorphic , and vegetative indica- tors for use in OHWM delineations in arid streams and categorized their typical landscape positions with respect...the presence of a bed and banks. Hydrogeomorphic units are distinct macro- scale geomorphic features formed within stream systems in response to

Method of producing microchannel and nanochannel articles

DOEpatents

D'Urso, Brian R.

2010-05-04

A method of making an article having channels therethrough includes the steps of: providing a ductile structure defining at least one macro-channel, the macro-channel containing a salt; drawing the ductile structure in the axial direction of the at least one macro-channel to reduce diameter of the macro-channel; and contacting the salt with a solvent to dissolve the salt to produce an article having at least one microchannel.

Dynamic response analysis of structure under time-variant interval process model

NASA Astrophysics Data System (ADS)

Xia, Baizhan; Qin, Yuan; Yu, Dejie; Jiang, Chao

2016-10-01

Due to the aggressiveness of the environmental factor, the variation of the dynamic load, the degeneration of the material property and the wear of the machine surface, parameters related with the structure are distinctly time-variant. Typical model for time-variant uncertainties is the random process model which is constructed on the basis of a large number of samples. In this work, we propose a time-variant interval process model which can be effectively used to deal with time-variant uncertainties with limit information. And then two methods are presented for the dynamic response analysis of the structure under the time-variant interval process model. The first one is the direct Monte Carlo method (DMCM) whose computational burden is relative high. The second one is the Monte Carlo method based on the Chebyshev polynomial expansion (MCM-CPE) whose computational efficiency is high. In MCM-CPE, the dynamic response of the structure is approximated by the Chebyshev polynomials which can be efficiently calculated, and then the variational range of the dynamic response is estimated according to the samples yielded by the Monte Carlo method. To solve the dependency phenomenon of the interval operation, the affine arithmetic is integrated into the Chebyshev polynomial expansion. The computational effectiveness and efficiency of MCM-CPE is verified by two numerical examples, including a spring-mass-damper system and a shell structure.

Macroprolactin, big-prolactin and potential effects on the misdiagnosis of hyperprolactinemia using the Beckman Coulter Access Prolactin assay.

PubMed

Ellis, M Jane; Livesey, John H; Soule, Steven G

2006-10-01

To examine whether use of the Beckman Coulter Access Prolactin (PRL) assay, which has low reactivity with macro-PRL, obviates the need for screening hyperprolactinemic samples. Samples from 1020 hyperprolactinemic individuals and 401 healthy volunteers were treated with polyethylene glycol (PEG). Macro-PRL was assessed from (1) percent PRL recovery, using cut-off values derived by gel filtration chromatography (GFC) and (2) significant (p<0.05) normalisation of PRL following PEG. PRL recovery was similar in volunteer and hyperprolactinemic samples (mean+/-SD 101+/-13% and 101+/-19%, respectively). In hyperprolactinemic samples, macro-PRL was identified from PRL recovery in 9.7%, although levels were moderate to high in only 3.9%. The total PRL normalised following PEG in 7.4%. Correlations of PRL recovery with the proportions of macro-, big- and monomeric PRL following GFC (n=30 samples, range of PRL and macro-PRL levels) were -0.89, -0.20 and 0.92, respectively. The big-PRL content was 0-28%. Regression analysis suggested that PEG precipitated both macro-PRL and big-PRL. Using the Access assay, macro-PRL can cause apparent hyperprolactinemia and big-PRL may cause misclassification of individuals. Screening using PEG is applicable to assays with low macro-PRL reactivity provided specific reference values are derived.

Master standard data quantity food production code. Macro elements for synthesizing production labor time.

PubMed

Matthews, M E; Waldvogel, C F; Mahaffey, M J; Zemel, P C

1978-06-01

Preparation procedures of standardized quantity formulas were analyzed for similarities and differences in production activities, and three entrée classifications were developed, based on these activities. Two formulas from each classification were selected, preparation procedures were divided into elements of production, and the MSD Quantity Food Production Code was applied. Macro elements not included in the existing Code were simulated, coded, assigned associated Time Measurement Units, and added to the MSD Quantity Food Production Code. Repeated occurrence of similar elements within production methods indicated that macro elements could be synthesized for use within one or more entrée classifications. Basic elements were grouped, simulated, and macro elements were derived. Macro elements were applied in the simulated production of 100 portions of each entrée formula. Total production time for each formula and average production time for each entrée classification were calculated. Application of macro elements indicated that this method of predetermining production time was feasible and could be adapted by quantity foodservice managers as a decision technique used to evaluate menu mix, production personnel schedules, and allocation of equipment usage. These macro elements could serve as a basis for further development and refinement of other macro elements which could be applied to a variety of menu item formulas.

A Review of PROC IRT in SAS

ERIC Educational Resources Information Center

Choi, Jinnie

2017-01-01

This article reviews PROC IRT, which was added to Statistical Analysis Software in 2014. We provide an introductory overview of a free version of SAS, describe what PROC IRT offers for item response theory (IRT) analysis and how one can use PROC IRT, and discuss how other SAS macros and procedures may compensate the IRT functionalities of PROC IRT.

"Neoliberal Spatial Technologies": On the Practices of Educational Policy Change

ERIC Educational Resources Information Center

Gulson, Kalervo N.

2007-01-01

This paper explores the spatial dimensions of neoliberalism, in relation to educational policy change in the inner-city of Sydney, Australia. It offers a response to Peck and Tickell's challenge that studies of neoliberalism are often undertaken as discrete macro- or micro-analyses without attention to the links between, and across, these scales.…

The Restructuring of Schooling in England: The Responses of Well-Positioned Headteachers

ERIC Educational Resources Information Center

Coldron, John; Crawford, Megan; Jones, Steve; Simkins, Tim

2014-01-01

Research to date about the English government's policy to make schools independent of local authorities (LAs) has looked at the "macro" level of national policy and at the "micro" level of the institution. The study of which this article is a part, explores changes at the "meso" level--the locality. The article…

Investment in constitutive immune function by north American elk experimentally maintained at two different population densities

Treesearch

Cynthia J. Downs; Kelley M. Stewart; Brian L. Dick; Daniel E Crocker

2015-01-01

Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous...

The Disaggregation of Value-Added Test Scores to Assess Learning Outcomes in Economics Courses

ERIC Educational Resources Information Center

Walstad, William B.; Wagner, Jamie

2016-01-01

This study disaggregates posttest, pretest, and value-added or difference scores in economics into four types of economic learning: positive, retained, negative, and zero. The types are derived from patterns of student responses to individual items on a multiple-choice test. The micro and macro data from the "Test of Understanding in College…

An Excel macro for generating trilinear plots.

PubMed

Shikaze, Steven G; Crowe, Allan S

2007-01-01

This computer note describes a method for creating trilinear plots in Microsoft Excel. Macros have been created in MS Excel's internal language: Visual Basic for Applications (VBA). A simple form has been set up to allow the user to input data from an Excel worksheet. The VBA macro is used to convert the triangular data (which consist of three columns of percentage data) into X-Y data. The macro then generates the axes, labels, and grid for the trilinear plot. The X-Y data are plotted as scatter data in Excel. By providing this macro in Excel, users can create trilinear plots in a quick, inexpensive manner.

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men.

PubMed

Phillips, Bethan E; Atherton, Philip J; Varadhan, Krishna; Limb, Marie C; Williams, John P; Smith, Kenneth

2016-05-01

The anabolic effects of nutrition on skeletal muscle may depend on adequate skeletal muscle perfusion, which is impaired in older people. Cocoa flavanols have been shown to improve flow-mediated dilation, an established measure of endothelial function. However, their effect on muscle microvascular blood flow is currently unknown. Therefore, the objective of this study was to explore links between the consumption of cocoa flavanols, muscle microvascular blood flow, and muscle protein synthesis (MPS) in response to nutrition in older men. To achieve this objective, leg blood flow (LBF), muscle microvascular blood volume (MBV), and MPS were measured under postabsorptive and postprandial (intravenous Glamin (Fresenius Kabi, Germany), dextrose to sustain glucose ∼7.5 mmol·L(-1)) conditions in 20 older men. Ten of these men were studied with no cocoa flavanol intervention and a further 10 were studied with the addition of 350 mg of cocoa flavanols at the same time that nutrition began. Leg (femoral artery) blood flow was measured by Doppler ultrasound, muscle MBV by contrast-enhanced ultrasound using Definity (Lantheus Medical Imaging, Mass., USA) perflutren contrast agent and MPS using [1, 2-(13)C2]leucine tracer techniques. Our results show that although older individuals do not show an increase in LBF or MBV in response to feeding, these absent responses are apparent when cocoa flavanols are given acutely with nutrition. However, this restoration in vascular responsiveness is not associated with improved MPS responses to nutrition. We conclude that acute cocoa flavanol supplementation improves muscle macro- and microvascular responses to nutrition, independently of modifying muscle protein anabolism.

When Corporate Social Responsibility (CSR) Meets Organizational Psychology: New Frontiers in Micro-CSR Research, and Fulfilling a Quid Pro Quo through Multilevel Insights

PubMed Central

Jones, David A.; Willness, Chelsea R.; Glavas, Ante

2017-01-01

Researchers, corporate leaders, and other stakeholders have shown increasing interest in Corporate Social Responsibility (CSR)—a company’s discretionary actions and policies that appear to advance societal well-being beyond its immediate financial interests and legal requirements. Spanning decades of research activity, the scholarly literature on CSR has been dominated by meso- and macro-level perspectives, such as studies within corporate strategy that examine relationships between firm-level indicators of social/environmental performance and corporate financial performance. In recent years, however, there has been an explosion of micro-oriented CSR research conducted at the individual level of analysis, especially with respect to studies on how and why job seekers and employees perceive and react to CSR practices. This micro-level focus is reflected in 12 articles published as a Research Topic collection in Frontiers in Psychology (Organizational Psychology Specialty Section) titled “CSR and organizational psychology: Quid pro quo.” In the present article, the authors summarize and integrate findings from these Research Topic articles. After describing some of the “new frontiers” these articles explore and create, the authors strive to fulfill a “quid pro quo” with some of the meso- and macro-oriented CSR literatures that paved the way for micro-CSR research. Specifically, the authors draw on insights from the Research Topic articles to inform a multilevel model that offers multiple illustrations of how micro-level processes among individual stakeholders can explain variability in meso (firm)-level relationships between CSR practices and corporate performance. The authors also explore an important implication of these multilevel processes for macro-level societal impact. PMID:28439247

When Corporate Social Responsibility (CSR) Meets Organizational Psychology: New Frontiers in Micro-CSR Research, and Fulfilling a Quid Pro Quo through Multilevel Insights.

PubMed

Jones, David A; Willness, Chelsea R; Glavas, Ante

2017-01-01

Researchers, corporate leaders, and other stakeholders have shown increasing interest in Corporate Social Responsibility (CSR)-a company's discretionary actions and policies that appear to advance societal well-being beyond its immediate financial interests and legal requirements. Spanning decades of research activity, the scholarly literature on CSR has been dominated by meso- and macro-level perspectives, such as studies within corporate strategy that examine relationships between firm-level indicators of social/environmental performance and corporate financial performance. In recent years, however, there has been an explosion of micro-oriented CSR research conducted at the individual level of analysis, especially with respect to studies on how and why job seekers and employees perceive and react to CSR practices. This micro-level focus is reflected in 12 articles published as a Research Topic collection in Frontiers in Psychology (Organizational Psychology Specialty Section) titled "CSR and organizational psychology: Quid pro quo." In the present article, the authors summarize and integrate findings from these Research Topic articles. After describing some of the "new frontiers" these articles explore and create, the authors strive to fulfill a "quid pro quo" with some of the meso- and macro-oriented CSR literatures that paved the way for micro-CSR research. Specifically, the authors draw on insights from the Research Topic articles to inform a multilevel model that offers multiple illustrations of how micro-level processes among individual stakeholders can explain variability in meso (firm)-level relationships between CSR practices and corporate performance. The authors also explore an important implication of these multilevel processes for macro-level societal impact.

Relationship between micro-porosity, water permeability and mechanical behavior in scaffolds for cartilage engineering.

PubMed

Vikingsson, L; Claessens, B; Gómez-Tejedor, J A; Gallego Ferrer, G; Gómez Ribelles, J L

2015-08-01

In tissue engineering the design and optimization of biodegradable polymeric scaffolds with a 3D-structure is an important field. The porous scaffold provide the cells with an adequate biomechanical environment that allows mechanotransduction signals for cell differentiation and the scaffolds also protect the cells from initial compressive loading. The scaffold have interconnected macro-pores that host the cells and newly formed tissue, while the pore walls should be micro-porous to transport nutrients and waste products. Polycaprolactone (PCL) scaffolds with a double micro- and macro-pore architecture have been proposed for cartilage regeneration. This work explores the influence of the micro-porosity of the pore walls on water permeability and scaffold compliance. A Poly(Vinyl Alcohol) with tailored mechanical properties has been used to simulate the growing cartilage tissue inside the scaffold pores. Unconfined and confined compression tests were performed to characterize both the water permeability and the mechanical response of scaffolds with varying size of micro-porosity while volume fraction of the macro-pores remains constant. The stress relaxation tests show that the stress response of the scaffold/hydrogel construct is a synergic effect determined by the performance of the both components. This is interesting since it suggests that the in vivo outcome of the scaffold is not only dependent upon the material architecture but also the growing tissue inside the scaffold׳s pores. On the other hand, confined compression results show that compliance of the scaffold is mainly controlled by the micro-porosity of the scaffold and less by hydrogel density in the scaffold pores. These conclusions bring together valuable information for customizing the optimal scaffold and to predict the in vivo mechanical behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

Charting a Future for Epidemiologic Training

PubMed Central

Samet, Jonathan M.; Chavez, Gilbert F.; Davies, Megan M.; Galea, Sandro; Hiatt, Robert A.; Hornung, Carlton A.; Khoury, Muin J.; Koo, Denise; Mays, Vickie M.; Remington, Patrick; Yarber, Laura

2015-01-01

Purpose To identify macro level trends that are changing the needs of epidemiologic research and practice and to develop and disseminate a set of competencies and recommendations for epidemiologic training that will be responsive to these changing needs. Methods There were three stages to the project: 1) assembly of a working group of senior epidemiologists from multiple sectors, 2) Identifying relevant literature, and 3) conducting key informant interviews with 15 experienced epidemiologists. Results Twelve macro trends were identified along with associated actions for the field and educational competencies. The macro trends include: 1) “Big Data”/ informatics, 2) the changing health communication environment, 3) the Affordable Care Act/health care system reform, 4) shifting demographics, 5) globalization, 6) emerging high throughput technologies (“omics”), 7) a greater focus on accountability, 8) privacy changes, 9) a greater focus on “upstream” causes of disease, 10) the emergence of translational sciences, 11) the growing centrality of team and trans-disciplinary science, and 12) the evolving funding environment. Conclusion Addressing these issues through curricular change is needed to allow the field of epidemiology to more fully reach and sustain its full potential to benefit population health and remain a scientific discipline that makes critical contributions to ensuring clinical, social, and population health. PMID:25976024

Macro-economic factors influencing the architectural business model shift in the pharmaceutical industry.

PubMed

Dierks, Raphaela Marie Louisa; Bruyère, Olivier; Reginster, Jean-Yves; Richy, Florent-Frederic

2016-10-01

Technological innovations, new regulations, increasing costs of drug productions and new demands are only few key drivers of a projected alternation in the pharmaceutical industry. The purpose of this review is to understand the macro economic factors responsible for the business model revolution to possess a competitive advantage over market players. Areas covered: Existing literature on macro-economic factors changing the pharmaceutical landscape has been reviewed to present a clear image of the current market environment. Expert commentary: Literature shows that pharmaceutical companies are facing an architectural alteration, however the evidence on the rationale driving the transformation is outstanding. Merger & Acquisitions (M&A) deals and collaborations are headlining the papers. Q1 2016 did show a major slowdown in M&A deals by volume since 2013 (with deal cancellations of Pfizer and Allergan, or the downfall of Valeant), but pharmaceutical analysts remain confident that this shortfall was a consequence of the equity market volatility. It seems likely that the shift to an M&A model will become apparent during the remainder of 2016, with deal announcements of Abbott Laboratories, AbbVie and Sanofi worth USD 45billion showing the appetite of big pharma companies to shift from the fully vertical integrated business model to more horizontal business models.

Solutocapillary Convection Effects on Polymeric Membrane Morphology

NASA Technical Reports Server (NTRS)

Krantz, William B.; Todd, Paul W.; Kinagurthu, Sanjay

1996-01-01

Macro voids are undesirable large pores in membranes used for purification. They form when membranes are cast as thin films on a smooth surface by evaporating solvent (acetone) from a polymer solution. There are two un-tested hypotheses explaining the growth of macro voids. One states that diffusion of the non-solvent (water) is solely responsible, while the other states that solutocapillary convection is the primary cause of macro void growth. Solutocapillary convection is flow-caused by a concentration induced surface-tension gradient. Macrovoid growth in the former hypothesis is gravity independent, while in the latter it is opposed by gravity. To distinguish between these two hypotheses, experiments were designed to cast membranes in zero-gravity. A semi-automated apparatus was designed and built for casting membranes during the 20 secs of zero-g time available in parabolic aircraft flight such as NASA's KC-135. The phase changes were monitored optically, and membrane morphology was evaluated by scanning electron microscopy (SEM). These studies appear to be the first quantitative studies of membrane casting in micro-gravity which incorporate real-time data acquisition. Morphological studies of membranes cast at 0, 1, and 1.8 g revealed the presence of numerous, sparse and no macrovoids respectively. These results are consistent with the predictions of the solutocapillary hypothesis of macrovoid growth.

From single fiber to macro-level mechanics: A structural finite-element model for elastomeric fibrous biomaterials

PubMed Central

D'Amore, Antonio; Amoroso, Nicholas; Gottardi, Riccardo; Hobson, Christopher; Carruthers, Christopher; Watkins, Simon; Wagner, William R.; Sacks, Michael S.

2014-01-01

In the present work, we demonstrate that the mesoscopic in-plane mechanical behavior of membrane elastomeric scaffolds can be simulated by replication of actual quantified fibrous geometries. Elastomeric electrospun polyurethane (ES-PEUU) scaffolds, with and without particulate inclusions, were utilized. Simulations were developed from experimentally-derived fiber network geometries, based on a range of scaffold isotropic and anisotropic behaviors. These were chosen to evaluate the effects on macro-mechanics based on measurable geometric parameters such as fiber intersections, connectivity, orientation, and diameter. Simulations were conducted with only the fiber material model parameters adjusted to match the macro-level mechanical test data. Fiber model validation was performed at the microscopic level by individual fiber mechanical tests using AFM. Results demonstrated very good agreement to the experimental data, and revealed the formation of extended preferential fiber orientations spanning the entire model space. We speculate that these emergent structures may be responsible for the tissue-like macroscale behaviors observed in electrospun scaffolds. To conclude, the modeling approach has implications for (1) gaining insight on the intricate relationship between fabrication variables, structure, and mechanics to manufacture more functional devices/materials, (2) elucidating the effects of cell or particulate inclusions on global construct mechanics, and (3) fabricating better performing tissue surrogates that could recapitulate native tissue mechanics. PMID:25128869

Applying discursive approaches to health psychology.

PubMed

Seymour-Smith, Sarah

2015-04-01

The aim of this paper is to outline the contribution of two strands of discursive research, glossed as 'macro' and 'micro,' to the field of health psychology. A further goal is to highlight some contemporary debates in methodology associated with the use of interview data versus more naturalistic data in qualitative health research. Discursive approaches provide a way of analyzing talk as a social practice that considers how descriptions are put together and what actions they achieve. A selection of recent examples of discursive research from one applied area of health psychology, studies of diet and obesity, are drawn upon in order to illustrate the specifics of both strands. 'Macro' discourse work in psychology incorporates a Foucauldian focus on the way that discourses regulate subjectivities, whereas the concept of interpretative repertoires affords more agency to the individual: both are useful for identifying the cultural context of talk. Both 'macro' and 'micro' strands focus on accountability to varying degrees. 'Micro' Discursive Psychology, however, pays closer attention to the sequential organization of constructions and focuses on naturalistic settings that allow for the inclusion of an analysis of the health professional. Diets are typically depicted as an individual responsibility in mainstream health psychology, but discursive research highlights how discourses are collectively produced and bound up with social practices. (c) 2015 APA, all rights reserved).

Narrative skills in deaf children who use spoken English: Dissociations between macro and microstructural devices.

PubMed

Jones, -A C; Toscano, E; Botting, N; Marshall, C-R; Atkinson, J R; Denmark, T; Herman, -R; Morgan, G

2016-12-01

Previous research has highlighted that deaf children acquiring spoken English have difficulties in narrative development relative to their hearing peers both in terms of macro-structure and with micro-structural devices. The majority of previous research focused on narrative tasks designed for hearing children that depend on good receptive language skills. The current study compared narratives of 6 to 11-year-old deaf children who use spoken English (N=59) with matched for age and non-verbal intelligence hearing peers. To examine the role of general language abilities, single word vocabulary was also assessed. Narratives were elicited by the retelling of a story presented non-verbally in video format. Results showed that deaf and hearing children had equivalent macro-structure skills, but the deaf group showed poorer performance on micro-structural components. Furthermore, the deaf group gave less detailed responses to inferencing probe questions indicating poorer understanding of the story's underlying message. For deaf children, micro-level devices most strongly correlated with the vocabulary measure. These findings suggest that deaf children, despite spoken language delays, are able to convey the main elements of content and structure in narrative but have greater difficulty in using grammatical devices more dependent on finer linguistic and pragmatic skills. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Probabilistic structural analysis using a general purpose finite element program

NASA Astrophysics Data System (ADS)

Riha, D. S.; Millwater, H. R.; Thacker, B. H.

1992-07-01

This paper presents an accurate and efficient method to predict the probabilistic response for structural response quantities, such as stress, displacement, natural frequencies, and buckling loads, by combining the capabilities of MSC/NASTRAN, including design sensitivity analysis and fast probability integration. Two probabilistic structural analysis examples have been performed and verified by comparison with Monte Carlo simulation of the analytical solution. The first example consists of a cantilevered plate with several point loads. The second example is a probabilistic buckling analysis of a simply supported composite plate under in-plane loading. The coupling of MSC/NASTRAN and fast probability integration is shown to be orders of magnitude more efficient than Monte Carlo simulation with excellent accuracy.

Diagnosing Undersampling Biases in Monte Carlo Eigenvalue and Flux Tally Estimates

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

Perfetti, Christopher M.; Rearden, Bradley T.; Marshall, William J.

2017-02-08

Here, this study focuses on understanding the phenomena in Monte Carlo simulations known as undersampling, in which Monte Carlo tally estimates may not encounter a sufficient number of particles during each generation to obtain unbiased tally estimates. Steady-state Monte Carlo simulations were performed using the KENO Monte Carlo tools within the SCALE code system for models of several burnup credit applications with varying degrees of spatial and isotopic complexities, and the incidence and impact of undersampling on eigenvalue and flux estimates were examined. Using an inadequate number of particle histories in each generation was found to produce a maximum bias of ~100 pcm in eigenvalue estimates and biases that exceeded 10% in fuel pin flux tally estimates. Having quantified the potential magnitude of undersampling biases in eigenvalue and flux tally estimates in these systems, this study then investigated whether Markov Chain Monte Carlo convergence metrics could be integrated into Monte Carlo simulations to predict the onset and magnitude of undersampling biases. Five potential metrics for identifying undersampling biases were implemented in the SCALE code system and evaluated for their ability to predict undersampling biases by comparing the test metric scores with the observed undersampling biases. Finally, of the five convergence metrics that were investigated, three (the Heidelberger-Welch relative half-width, the Gelman-Rubin more » $$\\hat{R}_c$$ diagnostic, and tally entropy) showed the potential to accurately predict the behavior of undersampling biases in the responses examined.« less

Final Technical Report: Mathematical Foundations for Uncertainty Quantification in Materials Design

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

Plechac, Petr; Vlachos, Dionisios G.

We developed path-wise information theory-based and goal-oriented sensitivity analysis and parameter identification methods for complex high-dimensional dynamics and in particular of non-equilibrium extended molecular systems. The combination of these novel methodologies provided the first methods in the literature which are capable to handle UQ questions for stochastic complex systems with some or all of the following features: (a) multi-scale stochastic models such as (bio)chemical reaction networks, with a very large number of parameters, (b) spatially distributed systems such as Kinetic Monte Carlo or Langevin Dynamics, (c) non-equilibrium processes typically associated with coupled physico-chemical mechanisms, driven boundary conditions, hybrid micro-macro systems,more » etc. A particular computational challenge arises in simulations of multi-scale reaction networks and molecular systems. Mathematical techniques were applied to in silico prediction of novel materials with emphasis on the effect of microstructure on model uncertainty quantification (UQ). We outline acceleration methods to make calculations of real chemistry feasible followed by two complementary tasks on structure optimization and microstructure-induced UQ.« less

Sequential use of the STICS crop model and of the MACRO pesticide fate model to simulate pesticides leaching in cropping systems.

PubMed

Lammoglia, Sabine-Karen; Moeys, Julien; Barriuso, Enrique; Larsbo, Mats; Marín-Benito, Jesús-María; Justes, Eric; Alletto, Lionel; Ubertosi, Marjorie; Nicolardot, Bernard; Munier-Jolain, Nicolas; Mamy, Laure

2017-03-01

The current challenge in sustainable agriculture is to introduce new cropping systems to reduce pesticides use in order to reduce ground and surface water contamination. However, it is difficult to carry out in situ experiments to assess the environmental impacts of pesticide use for all possible combinations of climate, crop, and soils; therefore, in silico tools are necessary. The objective of this work was to assess pesticides leaching in cropping systems coupling the performances of a crop model (STICS) and of a pesticide fate model (MACRO). STICS-MACRO has the advantage of being able to simulate pesticides fate in complex cropping systems and to consider some agricultural practices such as fertilization, mulch, or crop residues management, which cannot be accounted for with MACRO. The performance of STICS-MACRO was tested, without calibration, from measurements done in two French experimental sites with contrasted soil and climate properties. The prediction of water percolation and pesticides concentrations with STICS-MACRO was satisfactory, but it varied with the pedoclimatic context. The performance of STICS-MACRO was shown to be similar or better than that of MACRO. The improvement of the simulation of crop growth allowed better estimate of crop transpiration therefore of water balance. It also allowed better estimate of pesticide interception by the crop which was found to be crucial for the prediction of pesticides concentrations in water. STICS-MACRO is a new promising tool to improve the assessment of the environmental risks of pesticides used in cropping systems.

A Descriptive Guide to Trade Space Analysis

DTIC Science & Technology

2015-09-01

Development QFD Quality Function Deployment RSM Response Surface Method RSE Response Surface Equation SE Systems Engineering SME Subject Matter...surface equations ( RSEs ) as surrogate models. It uses the RSEs with Monte Carlo simulation to quantitatively explore changes across the surfaces to

Influence of ion chamber response on in-air profile measurements in megavoltage photon beams.

PubMed

Tonkopi, E; McEwen, M R; Walters, B R B; Kawrakow, I

2005-09-01

This article presents an investigation of the influence of the ion chamber response, including buildup caps, on the measurement of in-air off-axis ratio (OAR) profiles in megavoltage photon beams using Monte Carlo simulations with the EGSnrc system. Two new techniques for the calculation of OAR profiles are presented. Results of the Monte Carlo simulations are compared to measurements performed in 6, 10 and 25 MV photon beams produced by an Elekta Precise linac and shown to agree within the experimental and simulation uncertainties. Comparisons with calculated in-air kerma profiles demonstrate that using a plastic mini phantom gives more accurate air-kerma measurements than using high-Z material buildup caps and that the variation of chamber response with distance from the central axis must be taken into account.

Electromagnetic scaling functions within the Green's function Monte Carlo approach

DOE PAGES

Rocco, N.; Alvarez-Ruso, L.; Lovato, A.; ...

2017-07-24

We have studied the scaling properties of the electromagnetic response functions of 4He and 12C nuclei computed by the Green's function Monte Carlo approach, retaining only the one-body current contribution. Longitudinal and transverse scaling functions have been obtained in the relativistic and nonrelativistic cases and compared to experiment for various kinematics. The characteristic asymmetric shape of the scaling function exhibited by data emerges in the calculations in spite of the nonrelativistic nature of the model. The results are mostly consistent with scaling of zeroth, first, and second kinds. Our analysis reveals a direct correspondence between the scaling and the nucleon-densitymore » response functions. In conclusion, the scaling function obtained from the proton-density response displays scaling of the first kind, even more evidently than the longitudinal and transverse scaling functions« less

Electromagnetic scaling functions within the Green's function Monte Carlo approach

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

Rocco, N.; Alvarez-Ruso, L.; Lovato, A.

We have studied the scaling properties of the electromagnetic response functions of 4He and 12C nuclei computed by the Green's function Monte Carlo approach, retaining only the one-body current contribution. Longitudinal and transverse scaling functions have been obtained in the relativistic and nonrelativistic cases and compared to experiment for various kinematics. The characteristic asymmetric shape of the scaling function exhibited by data emerges in the calculations in spite of the nonrelativistic nature of the model. The results are mostly consistent with scaling of zeroth, first, and second kinds. Our analysis reveals a direct correspondence between the scaling and the nucleon-densitymore » response functions. In conclusion, the scaling function obtained from the proton-density response displays scaling of the first kind, even more evidently than the longitudinal and transverse scaling functions« less

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

Agnes, P.; et al.

A Geant4-based Monte Carlo package named G4DS has been developed to simulate the response of DarkSide-50, an experiment operating since 2013 at LNGS, designed to detect WIMP interactions in liquid argon. In the process of WIMP searches, DarkSide-50 has achieved two fundamental milestones: the rejection of electron recoil background with a power of ~10^7, using the pulse shape discrimination technique, and the measurement of the residual 39Ar contamination in underground argon, ~3 orders of magnitude lower with respect to atmospheric argon. These results rely on the accurate simulation of the detector response to the liquid argon scintillation, its ionization, andmore » electron-ion recombination processes. This work provides a complete overview of the DarkSide Monte Carlo and of its performance, with a particular focus on PARIS, the custom-made liquid argon response model.« less

Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

NASA Astrophysics Data System (ADS)

Sunil, C.; Tyagi, Mohit; Biju, K.; Shanbhag, A. A.; Bandyopadhyay, T.

2015-12-01

The scarcity and the high cost of 3He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am-Be neutron source shows promise of being used as rem counter.

Development of the Macro Command Editing Executive System for Factory Workers-Oriented Programless Visual Inspection System

NASA Astrophysics Data System (ADS)

Anezaki, Takashi; Wakitani, Kouichi; Nakamura, Masatoshi; Kubo, Hiroyasu

Because visual inspection systems are difficult to tune, they create many problems for the kaizen process. This results in increased development costs and time to assure that the inspection systems function properly. In order to improve inspection system development, we designed an easy-tuning system called a “Program-less” visual inspection system. The ROI macro command which consisted of eight kinds of shape recognition macro commands and decision, operation, control commands was built. Furthermore, the macro command editing executive system was developed by the operation of only the GUI without editing source program. The validity of the ROI macro command was proved by the application of 488 places.

Primordial 4He constraints on inelastic macro dark matter revisited

NASA Astrophysics Data System (ADS)

Jacobs, David M.; Allwright, Gwyneth; Mafune, Mpho; Manikumar, Samyukta; Weltman, Amanda

2016-11-01

At present, the best model for the evolution of the cosmos requires that dark matter make up approximately 25% of the energy content of the Universe. Most approaches to explain the microscopic nature of dark matter, to date, have assumed its composition to be of intrinsically weakly interacting particles; however, this need not be the case to have consistency with all extant observations. Given decades of inconclusive evidence to support any dark matter candidate, there is strong motivation to consider alternatives to the standard particle scenario. One such example is macro dark matter, a class of candidates (macros) that could interact strongly with the particles of the Standard Model, have large masses and physical sizes, and yet behave as dark matter. Macros that scatter completely inelastically could have altered the primordial production of the elements, and macro charge-dependent constraints have been obtained previously. Here we reconsider the phenomenology of inelastically interacting macros on the abundance of primordially produced 4He and revise previous constraints by also taking into account improved measurements of the primordial 4He abundance. The constraints derived here are limited in applicability to only leptophobic macros that have a surface potential V (RX)≳0.5 MeV . However, an important conclusion from our analysis is that even neutral macros would likely affect the abundance of the light elements. Therefore, constraints on that scenario are possible and are currently an open question.

MCNP-REN - A Monte Carlo Tool for Neutron Detector Design Without Using the Point Model

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

Abhold, M.E.; Baker, M.C.

1999-07-25

The development of neutron detectors makes extensive use of the predictions of detector response through the use of Monte Carlo techniques in conjunction with the point reactor model. Unfortunately, the point reactor model fails to accurately predict detector response in common applications. For this reason, the general Monte Carlo N-Particle code (MCNP) was modified to simulate the pulse streams that would be generated by a neutron detector and normally analyzed by a shift register. This modified code, MCNP - Random Exponentially Distributed Neutron Source (MCNP-REN), along with the Time Analysis Program (TAP) predict neutron detector response without using the pointmore » reactor model, making it unnecessary for the user to decide whether or not the assumptions of the point model are met for their application. MCNP-REN is capable of simulating standard neutron coincidence counting as well as neutron multiplicity counting. Measurements of MOX fresh fuel made using the Underwater Coincidence Counter (UWCC) as well as measurements of HEU reactor fuel using the active neutron Research Reactor Fuel Counter (RRFC) are compared with calculations. The method used in MCNP-REN is demonstrated to be fundamentally sound and shown to eliminate the need to use the point model for detector performance predictions.« less

Monte Carlo source simulation technique for solution of interference reactions in INAA experiments: a preliminary report

NASA Astrophysics Data System (ADS)

Allaf, M. Athari; Shahriari, M.; Sohrabpour, M.

2004-04-01

A new method using Monte Carlo source simulation of interference reactions in neutron activation analysis experiments has been developed. The neutron spectrum at the sample location has been simulated using the Monte Carlo code MCNP and the contributions of different elements to produce a specified gamma line have been determined. The produced response matrix has been used to measure peak areas and the sample masses of the elements of interest. A number of benchmark experiments have been performed and the calculated results verified against known values. The good agreement obtained between the calculated and known values suggests that this technique may be useful for the elimination of interference reactions in neutron activation analysis.

Multi-level damage identification with response reconstruction

NASA Astrophysics Data System (ADS)

Zhang, Chao-Dong; Xu, You-Lin

2017-10-01

Damage identification through finite element (FE) model updating usually forms an inverse problem. Solving the inverse identification problem for complex civil structures is very challenging since the dimension of potential damage parameters in a complex civil structure is often very large. Aside from enormous computation efforts needed in iterative updating, the ill-condition and non-global identifiability features of the inverse problem probably hinder the realization of model updating based damage identification for large civil structures. Following a divide-and-conquer strategy, a multi-level damage identification method is proposed in this paper. The entire structure is decomposed into several manageable substructures and each substructure is further condensed as a macro element using the component mode synthesis (CMS) technique. The damage identification is performed at two levels: the first is at macro element level to locate the potentially damaged region and the second is over the suspicious substructures to further locate as well as quantify the damage severity. In each level's identification, the damage searching space over which model updating is performed is notably narrowed down, not only reducing the computation amount but also increasing the damage identifiability. Besides, the Kalman filter-based response reconstruction is performed at the second level to reconstruct the response of the suspicious substructure for exact damage quantification. Numerical studies and laboratory tests are both conducted on a simply supported overhanging steel beam for conceptual verification. The results demonstrate that the proposed multi-level damage identification via response reconstruction does improve the identification accuracy of damage localization and quantization considerably.

Accounting for uncertainty in pedotransfer functions in vulnerability assessments of pesticide leaching to groundwater.

PubMed

Stenemo, Fredrik; Jarvis, Nicholas

2007-09-01

A simulation tool for site-specific vulnerability assessments of pesticide leaching to groundwater was developed, based on the pesticide fate and transport model MACRO, parameterized using pedotransfer functions and reasonable worst-case parameter values. The effects of uncertainty in the pedotransfer functions on simulation results were examined for 48 combinations of soils, pesticides and application timings, by sampling pedotransfer function regression errors and propagating them through the simulation model in a Monte Carlo analysis. An uncertainty factor, f(u), was derived, defined as the ratio between the concentration simulated with no errors, c(sim), and the 80th percentile concentration for the scenario. The pedotransfer function errors caused a large variation in simulation results, with f(u) ranging from 1.14 to 1440, with a median of 2.8. A non-linear relationship was found between f(u) and c(sim), which can be used to account for parameter uncertainty by correcting the simulated concentration, c(sim), to an estimated 80th percentile value. For fine-textured soils, the predictions were most sensitive to errors in the pedotransfer functions for two parameters regulating macropore flow (the saturated matrix hydraulic conductivity, K(b), and the effective diffusion pathlength, d) and two water retention function parameters (van Genuchten's N and alpha parameters). For coarse-textured soils, the model was also sensitive to errors in the exponent in the degradation water response function and the dispersivity, in addition to K(b), but showed little sensitivity to d. To reduce uncertainty in model predictions, improved pedotransfer functions for K(b), d, N and alpha would therefore be most useful. 2007 Society of Chemical Industry

Accuracy of Monte Carlo photon transport simulation in characterizing brachytherapy dosimeter energy-response artefacts

NASA Astrophysics Data System (ADS)

Das, R. K.; Li, Z.; Perera, H.; Williamson, J. F.

1996-06-01

Practical dosimeters in brachytherapy, such as thermoluminescent dosimeters (TLD) and diodes, are usually calibrated against low-energy megavoltage beams. To measure absolute dose rate near a brachytherapy source, it is necessary to establish the energy response of the detector relative to that of the calibration energy. The purpose of this paper is to assess the accuracy of Monte Carlo photon transport (MCPT) simulation in modelling the absolute detector response as a function of detector geometry and photon energy. We have exposed two different sizes of TLD-100 (LiF chips) and p-type silicon diode detectors to calibrated , HDR source and superficial x-ray beams. For the Scanditronix electron-field diode, the relative detector response, defined as the measured detector readings per measured unit of air kerma, varied from (40 kVp beam) to ( beam). Similarly for the large and small chips the same quantity varied from and , respectively. Monte Carlo simulation was used to calculate the absorbed dose to the active volume of the detector per unit air kerma. If the Monte Carlo simulation is accurate, then the absolute detector response, which is defined as the measured detector reading per unit dose absorbed by the active detector volume, and is calculated by Monte Carlo simulation, should be a constant. For the diode, the absolute response is . For TLDs of size the absolute response is and for TLDs of it is . From the above results we can conclude that the absolute response function of detectors (TLDs and diodes) is directly proportional to absorbed dose by the active volume of the detector and is independent of beam quality.

[Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters].

PubMed

Shan, Xiu-Juan; Zhuang, Zhi-Meng; Jin, Xian-Shi; Dai, Fang-Qun

2011-12-01

Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg x h(-1) and 1800 kg x h(-1) in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5 degrees E, 28.5 degrees N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus, and Acropoma japonicum) and pelagic species (Psenopsis anomala, Octopus variabilis) and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.

Crowd macro state detection using entropy model

NASA Astrophysics Data System (ADS)

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

2015-08-01

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

Improvement of aquaponic performance through micro- and macro-nutrient addition.

PubMed

Ru, Dongyun; Liu, Jikai; Hu, Zhen; Zou, Yina; Jiang, Liping; Cheng, Xiaodian; Lv, Zhenting

2017-07-01

Aquaponics is one of the "zero waste" industry in the twenty-first century, and is considered to be one of the major trends for the future development of agriculture. However, the low nitrogen utilization efficiency (NUE) restricted its widely application. To date, many attempts have been conducted to improve its NUE. In the present study, effect of micro- and macro-nutrient addition on performance of tilapia-pak choi aquaponics was investigated. Results showed that the addition of micro- and macro-nutrients improved the growth of plant directly and facilitated fish physiology indirectly, which subsequently increased NUE of aquaponics from 40.42 to 50.64%. In addition, remarkable lower total phosphorus concentration was obtained in aquaponics with micro- and macro-nutrient addition, which was attributed to the formation of struvite. Most of the added micro-nutrients were enriched in plant root, while macro-nutrients mainly existed in water. Moreover, no enrichment of micro- and macro-nutrients in aquaponic products (i.e., fish and plant leaves) was observed, indicating that it had no influence on food safety. The findings here reported manifest that appropriate addition of micro- and macro-nutrients to aquaponics is necessary, and would improve its economic feasibility.

Linear and Non-Linear Dielectric Response of Periodic Systems from Quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Umari, Paolo

2006-03-01

We present a novel approach that allows to calculate the dielectric response of periodic systems in the quantum Monte Carlo formalism. We employ a many-body generalization for the electric enthalpy functional, where the coupling with the field is expressed via the Berry-phase formulation for the macroscopic polarization. A self-consistent local Hamiltonian then determines the ground-state wavefunction, allowing for accurate diffusion quantum Monte Carlo calculations where the polarization's fixed point is estimated from the average on an iterative sequence. The polarization is sampled through forward-walking. This approach has been validated for the case of the polarizability of an isolated hydrogen atom, and then applied to a periodic system. We then calculate the linear susceptibility and second-order hyper-susceptibility of molecular-hydrogen chains whith different bond-length alternations, and assess the quality of nodal surfaces derived from density-functional theory or from Hartree-Fock. The results found are in excellent agreement with the best estimates obtained from the extrapolation of quantum-chemistry calculations.P. Umari, A.J. Williamson, G. Galli, and N. MarzariPhys. Rev. Lett. 95, 207602 (2005).

Assessing the Macro-Level Correlates of Malware Infections Using a Routine Activities Framework.

PubMed

Holt, Thomas J; Burruss, George W; Bossler, Adam M

2018-05-01

The ability to gain unauthorized access to computer systems to engage in espionage and data theft poses a massive threat to individuals worldwide. There has been minimal focus, however, on the role of malicious software, or malware, which can automate this process. This study examined the macro-correlates of malware infection at the national level by using an open repository of known malware infections and utilizing a routine activities framework. Negative inflated binomial models for counts indicated that nations with greater technological infrastructure, more political freedoms, and with less organized crime financial impact were more likely to report malware infections. The number of Computer Emergency Response Teams (CERTs) in a nation was not significantly related with reported malware infection. The implications of the study for the understanding of malware infection, routine activity theory, and target-hardening strategies are discussed.

The Use of Lotus 1-2-3 Macros in Engineering Calculations.

ERIC Educational Resources Information Center

Rosen, Edward M.

1990-01-01

Described are the use of spreadsheet programs in chemical engineering calculations using Lotus 1-2-3 macros. Discusses the macro commands, subroutine operations, and solution of partial differential equation. Provides examples of the subroutine programs and spreadsheet solution. (YP)

Framing Higher Education: Questions and Responses in the British Social Attitudes Survey, 1983-2010

ERIC Educational Resources Information Center

Mountford-Zimdars, Anna; Jones, Steven; Sullivan, Alice; Heath, Anthony

2013-01-01

This article focuses on questions and attitudes towards higher education in the British Social Attitudes (BSA) survey series. First, we analyse the changing BSA questions (1983-2010) in the context of key policy reports. Our results show that changes in the framing of higher education questions correspond with changes in the macro-discourse of…

Soil CO2 flux in response to elevated atmospheric CO2 and nitrogen fertilization: patterns and methods

Treesearch

James M. Vose; Katherine J. Elliott; D.W. Johnson

1995-01-01

The evolution of carbon dioxide (CO2) from soils is due to the metabolic activity of roots, mycorrhizae, and soil micro- and macro-organisms. Although precise estimates of carbon (C) recycled to the atmosphere from belowground sources are unavailable, Musselman and Fox (1991) propose that the belowground contribution exceeds 100 Pg y-1...

The RAND Change Agent Study Ten Years Later: Macro Perspectives and Micro Realities.

ERIC Educational Resources Information Center

McLaughlin, Milbrey Wallin

From 1973 to 1978, the Rand Corporation conducted a national study of local public schools' responses to various federal programs requiring educational change--Title III of the 1965 Elementary and Secondary Education Act (ESEA), Title VII of the ESEA, programs financed by the 1968 Vocational Education Act, and the Right-to-Read program. This paper…

Explaining Cross-State Differences in Elderly Suicide Rates and Identifying State-Level Public Policy Responses that Reduce Rates

ERIC Educational Resources Information Center

Giles-Sims, Jean; Lockhart, Charles

2006-01-01

Elderly Americans commit suicide at higher rates than other age groups. We contend that macro- and micro-social variables contribute distinct aspects to explanations of this tragic loss: the former focus on circumstances that affect overall rates, the latter reveal why certain individuals succumb to suicide. Our analysis focuses on the…

A Response to "Social Privilege, Social Justice, and Group Counseling: An Inquiry": Social Privilege--Counselors' Competence with Systemically Determined Inequalities

ERIC Educational Resources Information Center

Roysircar, Gargi

2008-01-01

The literature is extensive about explanatory behavioral and social effects with an individual or micro focus. A somewhat less programmatic literature exits in social justice that considers systemic or macro factors: for example, mental health service and its structures that perpetuate inequity and disparity in service delivery. Social privilege…

Downward delegation of implantable cardioverter defibrillator decision-making in a restricted-resource environment: the pitfalls of bedside rationing.

PubMed

Simpson, Christopher S; Hoffmaster, Barry; Dorian, Paul

2005-05-15

Implantable cardioverter defibrillators have been shown to reduce all-cause mortality in some patient populations at risk of sudden death. New Canadian guidelines recommend implantable cardioverter defibrillator therapy for these patients. However, the need for these devices exceeds the funded volumes in many Canadian jurisdictions. As a result, rationing of this resource has been necessary. While rationing at the macro (Ministry of Health) and meso (hospital) levels has achieved some level of acceptance by society, the responsibility for the decisions taken at the micro (individual) patient level actually rests with the physician at the bedside. This 'bedside rationing' creates a moral dilemma for physicians, who are torn between their traditional fiduciary role as 'patient advocate' and the competing role of 'gatekeeper'. This 'downward delegation' of rationing decision-making obscures the reality that rationing occurs, and encourages covert, opaque and inconsistent approaches. The remedy is the development of fair, legitimate procedures for making rationing decisions that include guidelines that structure and constrain those decisions. Macro- and meso-level stakeholders must also recognize and take responsibility for their part in restricting resources in a broadly inclusive and transparent process.

A large-scale, long-term study of scale drift: The micro view and the macro view

NASA Astrophysics Data System (ADS)

He, W.; Li, S.; Kingsbury, G. G.

2016-11-01

The development of measurement scales for use across years and grades in educational settings provides unique challenges, as instructional approaches, instructional materials, and content standards all change periodically. This study examined the measurement stability of a set of Rasch measurement scales that have been in place for almost 40 years. In order to investigate the stability of these scales, item responses were collected from a large set of students who took operational adaptive tests using items calibrated to the measurement scales. For the four scales that were examined, item samples ranged from 2183 to 7923 items. Each item was administered to at least 500 students in each grade level, resulting in approximately 3000 responses per item. Stability was examined at the micro level analysing change in item parameter estimates that have occurred since the items were first calibrated. It was also examined at the macro level, involving groups of items and overall test scores for students. Results indicated that individual items had changes in their parameter estimates, which require further analysis and possible recalibration. At the same time, the results at the total score level indicate substantial stability in the measurement scales over the span of their use.

Angular dependence of the nanoDot OSL dosimeter.

PubMed

Kerns, James R; Kry, Stephen F; Sahoo, Narayan; Followill, David S; Ibbott, Geoffrey S

2011-07-01

Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight/OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system. Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, as well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX. When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found. A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions.

Angular dependence of the nanoDot OSL dosimeter

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

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight/OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system. Methods: Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, asmore » well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX. Results: When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found. Conclusions: A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions.« less

Angular dependence of the nanoDot OSL dosimeter

PubMed Central

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan; Followill, David S.; Ibbott, Geoffrey S.

2011-01-01

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight∕OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system.Methods: Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, as well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX.Results: When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found.Conclusions: A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions. PMID:21858992

Complex fluids with mobile charge-regulating macro-ions

NASA Astrophysics Data System (ADS)

Markovich, Tomer; Andelman, David; Podgornik, Rudi

2017-10-01

We generalize the concept of charge regulation of ionic solutions, and apply it to complex fluids with mobile macro-ions having internal non-electrostatic degrees of freedom. The suggested framework provides a convenient tool for investigating systems where mobile macro-ions can self-regulate their charge (e.g., proteins). We show that even within a simplified charge-regulation model, the charge dissociation equilibrium results in different and notable properties. Consequences of the charge regulation include a positional dependence of the effective charge of the macro-ions, a non-monotonic dependence of the effective Debye screening length on the concentration of the monovalent salt, a modification of the electric double-layer structure, and buffering by the macro-ions of the background electrolyte.

The relationship between venture capital investment and macro economic variables via statistical computation method

NASA Astrophysics Data System (ADS)

Aygunes, Gunes

2017-07-01

The objective of this paper is to survey and determine the macroeconomic factors affecting the level of venture capital (VC) investments in a country. The literary depends on venture capitalists' quality and countries' venture capital investments. The aim of this paper is to give relationship between venture capital investment and macro economic variables via statistical computation method. We investigate the countries and macro economic variables. By using statistical computation method, we derive correlation between venture capital investments and macro economic variables. According to method of logistic regression model (logit regression or logit model), macro economic variables are correlated with each other in three group. Venture capitalists regard correlations as a indicator. Finally, we give correlation matrix of our results.

[The effect of perceived work and organizational chracteristics on psychological distress and intention to quit of information technology professionals].

PubMed

Tominaga, Maki; Asakura, Takashi

2006-03-01

The information technology (IT) and service industry in Japan is known to have many work-related stressors, and requires more effective stress reduction to control an elevated turnover rate and adverse health effects. However, little research has been performed using either individual or organizational outcomes (e.g., psychological distress and intention to quit) to determine micro and macro-level stressors on information technology (IT) professionals. This study aimed to examine the effect of perceived work and organizational characteristics (PWOC) as micro and macro-level stressors on psychological distress and intention to quit, controlling for profitability of the organization and individual characteristics on IT professionals in Japan. We conducted a web-based questionnaire at fifty-three Japanese IT-related companies. From May to June of 2003, ten to thirty people from each company, who were chosen according to quota method indicators through the labor unions, voluntarily participated in this study. Participants accessed our webpage, which was designed with a self-administrated questionnaire and was accessible by password. The data they entered were sent to our database automatically. The questionnaire consisted of items concerning socio-demographic status; office size; employment characteristics; work hour characteristics; profitability of the organization; a novel 29-item scale (PWOC); as well as individual characteristics. The response rate was 66% (n = 1049). For the purpose of this study, we analyzed data on an IT engineers' group separately (n = 871). Hierarchical multiple regression analysis showed that each model explained 23% and 26% of the variance in psychological distress and intention to quit, respectively. PWOC sub-scales, which are related to macro-level stressors (e.g., undeveloped management systems and career and future ambiguity), affect not only psychological distress but also intention to quit. Objective data of macro-level stressors such as increased profitability determine intention to quit, independently controlling for their PWOC. Also, growth need strength was an important personal characteristic for psychological distress. The results allow us to speculate on macro as well as micro-level stressors for ways that organizations might reduce IT professionals' stress and increase their productivity. This study suggests that macro-level stressors are important factors for psychological distress and intention to quit for IT professionals, as well as micro-level stressors. Since occupational stress is costly in terms of organizational outcomes, further research on occupational stress measuring individual and organizational outcomes both within and beyond the Japanese IT industry should prove useful.

Output power fluctuations due to different weights of macro particles used in particle-in-cell simulations of Cerenkov devices

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

Bao, Rong; Li, Yongdong; Liu, Chunliang

2016-07-15

The output power fluctuations caused by weights of macro particles used in particle-in-cell (PIC) simulations of a backward wave oscillator and a travelling wave tube are statistically analyzed. It is found that the velocities of electrons passed a specific slow-wave structure form a specific electron velocity distribution. The electron velocity distribution obtained in PIC simulation with a relative small weight of macro particles is considered as an initial distribution. By analyzing this initial distribution with a statistical method, the estimations of the output power fluctuations caused by different weights of macro particles are obtained. The statistical method is verified bymore » comparing the estimations with the simulation results. The fluctuations become stronger with increasing weight of macro particles, which can also be determined reversely from estimations of the output power fluctuations. With the weights of macro particles optimized by the statistical method, the output power fluctuations in PIC simulations are relatively small and acceptable.« less

MacroH2A1.1 regulates mitochondrial respiration by limiting nuclear NAD+ consumption.

PubMed

Posavec Marjanović, Melanija; Hurtado-Bagès, Sarah; Lassi, Maximilian; Valero, Vanesa; Malinverni, Roberto; Delage, Hélène; Navarro, Miriam; Corujo, David; Guberovic, Iva; Douet, Julien; Gama-Perez, Pau; Garcia-Roves, Pablo M; Ahel, Ivan; Ladurner, Andreas G; Yanes, Oscar; Bouvet, Philippe; Suelves, Mònica; Teperino, Raffaele; Pospisilik, J Andrew; Buschbeck, Marcus

2017-11-01

Histone variants are structural components of eukaryotic chromatin that can replace replication-coupled histones in the nucleosome. The histone variant macroH2A1.1 contains a macrodomain capable of binding NAD + -derived metabolites. Here we report that macroH2A1.1 is rapidly induced during myogenic differentiation through a switch in alternative splicing, and that myotubes that lack macroH2A1.1 have a defect in mitochondrial respiratory capacity. We found that the metabolite-binding macrodomain was essential for sustained optimal mitochondrial function but dispensable for gene regulation. Through direct binding, macroH2A1.1 inhibits basal poly-ADP ribose polymerase 1 (PARP-1) activity and thus reduces nuclear NAD + consumption. The resultant accumulation of the NAD + precursor NMN allows for maintenance of mitochondrial NAD + pools that are critical for respiration. Our data indicate that macroH2A1.1-containing chromatin regulates mitochondrial respiration by limiting nuclear NAD + consumption and establishing a buffer of NAD + precursors in differentiated cells.

Active vertical tail buffeting suppression based on macro fiber composites

NASA Astrophysics Data System (ADS)

Zou, Chengzhe; Li, Bin; Liang, Li; Wang, Wei

2016-04-01

Aerodynamic buffet is unsteady airflow exerting forces onto a surface, which can lead to premature fatigue damage of aircraft vertical tail structures, especially for aircrafts with twin vertical tails at high angles of attack. In this work, Macro Fiber Composite (MFC), which can provide strain actuation, was used as the actuator for the buffet-induced vibration control, and the positioning of the MFC patches was led by the strain energy distribution on the vertical tail. Positive Position Feedback (PPF) control algorithm has been widely used for its robustness and simplicity in practice, and consequently it was developed to suppress the buffet responses of first bending and torsional mode of vertical tail. However, its performance is usually attenuated by the phase contributions from non-collocated sensor/actuator configuration and plants. The phase lag between the input and output signals of the control system was identified experimentally, and the phase compensation was considered in the PPF control algorithm. The simulation results of the amplitude frequency of the closed-loop system showed that the buffet response was alleviated notably around the concerned bandwidth. Then the wind tunnel experiment was conducted to verify the effectiveness of MFC actuators and compensated PPF, and the Root Mean Square (RMS) of the acceleration response was reduced 43.4%, 28.4% and 39.5%, respectively, under three different buffeting conditions.

Strange Bedfellows: The Catholic Church and Brazilian National AIDS Program in the Response to HIV/AIDS in Brazil

PubMed Central

Murray, Laura R.; Garcia, Jonathan; Muñoz-Laboy, Miguel; Parker, Richard G.

2011-01-01

The HIV epidemic has raised important tensions in the relationship between Church and State in many parts of Latin America where government policies frequently negotiate secularity with religious belief and doctrine. Brazil represents a unique country in the region due to the presence of a national religious response to HIV/AIDS articulated through the formal structures of the Catholic Church. As part of an institutional ethnography on religion and HIV/AIDS in Brazil, we conducted an extended, multi-site ethnography from October 2005 through March of 2009 to explore the relationship between the Catholic Church and the Brazilian National AIDS Program. This case study links a national, macro-level response of governmental and religious institutions with the enactment of these politics and dogmas on a local level. Shared values in solidarity and citizenship, similar organizational structures, and complex interests in forming mutually beneficial alliances were the factors that emerged as the bases for the strong partnership between the two institutions. Dichotomies of Church and State and micro and macro forces were often blurred as social actors responded to the epidemic while also upholding the ideologies of the institutions they represented. We argue that the relationship between the Catholic Church and the National AIDS Program was formalized in networks mediated through personal relationships and political opportunity structures that provided incentives for both institutions to collaborate. PMID:21324573

Chain pooling to minimize prediction error in subset regression. [Monte Carlo studies using population models

NASA Technical Reports Server (NTRS)

Holms, A. G.

1974-01-01

Monte Carlo studies using population models intended to represent response surface applications are reported. Simulated experiments were generated by adding pseudo random normally distributed errors to population values to generate observations. Model equations were fitted to the observations and the decision procedure was used to delete terms. Comparison of values predicted by the reduced models with the true population values enabled the identification of deletion strategies that are approximately optimal for minimizing prediction errors.

Intersection crash prediction modeling with macro-level data from various geographic units.

PubMed

Lee, Jaeyoung; Abdel-Aty, Mohamed; Cai, Qing

2017-05-01

There have been great efforts to develop traffic crash prediction models for various types of facilities. The crash models have played a key role to identify crash hotspots and evaluate safety countermeasures. In recent, many macro-level crash prediction models have been developed to incorporate highway safety considerations in the long-term transportation planning process. Although the numerous macro-level studies have found that a variety of demographic and socioeconomic zonal characteristics have substantial effects on traffic safety, few studies have attempted to coalesce micro-level with macro-level data from existing geographic units for estimating crash models. In this study, the authors have developed a series of intersection crash models for total, severe, pedestrian, and bicycle crashes with macro-level data for seven spatial units. The study revealed that the total, severe, and bicycle crash models with ZIP-code tabulation area data performs the best, and the pedestrian crash models with census tract-based data outperforms the competing models. Furthermore, it was uncovered that intersection crash models can be drastically improved by only including random-effects for macro-level entities. Besides, the intersection crash models are even further enhanced by including other macro-level variables. Lastly, the pedestrian and bicycle crash modeling results imply that several macro-level variables (e.g., population density, proportions of specific age group, commuters who walk, or commuters using bicycle, etc.) can be a good surrogate exposure for those crashes. Copyright © 2017 Elsevier Ltd. All rights reserved.

A probabilistic seismic risk assessment procedure for nuclear power plants: (I) Methodology

USGS Publications Warehouse

Huang, Y.-N.; Whittaker, A.S.; Luco, N.

2011-01-01

A new procedure for probabilistic seismic risk assessment of nuclear power plants (NPPs) is proposed. This procedure modifies the current procedures using tools developed recently for performance-based earthquake engineering of buildings. The proposed procedure uses (a) response-based fragility curves to represent the capacity of structural and nonstructural components of NPPs, (b) nonlinear response-history analysis to characterize the demands on those components, and (c) Monte Carlo simulations to determine the damage state of the components. The use of response-rather than ground-motion-based fragility curves enables the curves to be independent of seismic hazard and closely related to component capacity. The use of Monte Carlo procedure enables the correlation in the responses of components to be directly included in the risk assessment. An example of the methodology is presented in a companion paper to demonstrate its use and provide the technical basis for aspects of the methodology. ?? 2011 Published by Elsevier B.V.

Characteristic evaluation of a Lithium-6 loaded neutron coincidence spectrometer.

PubMed

Hayashi, M; Kaku, D; Watanabe, Y; Sagara, K

2007-01-01

Characteristics of a (6)Li-loaded neutron coincidence spectrometer were investigated from both measurements and Monte Carlo simulations. The spectrometer consists of three (6)Li-glass scintillators embedded in a liquid organic scintillator BC-501A, which can detect selectively neutrons that deposit the total energy in the BC-501A using a coincidence signal generated from the capture event of thermalised neutrons in the (6)Li-glass scintillators. The relative efficiency and the energy response were measured using 4.7, 7.2 and 9.0 MeV monoenergetic neutrons. The measured ones were compared with the Monte Carlo calculations performed by combining the neutron transport code PHITS and the scintillator response calculation code SCINFUL. The experimental light output spectra were in good agreement with the calculated ones in shape. The energy dependence of the detection efficiency was reproduced by the calculation. The response matrices for 1-10 MeV neutrons were finally obtained.

The specific purpose Monte Carlo code McENL for simulating the response of epithermal neutron lifetime well logging tools

NASA Astrophysics Data System (ADS)

Prettyman, T. H.; Gardner, R. P.; Verghese, K.

1993-08-01

A new specific purpose Monte Carlo code called McENL for modeling the time response of epithermal neutron lifetime tools is described. The weight windows technique, employing splitting and Russian roulette, is used with an automated importance function based on the solution of an adjoint diffusion model to improve the code efficiency. Complete composition and density correlated sampling is also included in the code, and can be used to study the effect on tool response of small variations in the formation, borehole, or logging tool composition and density. An illustration of the latter application is given for the density of a thermal neutron filter. McENL was benchmarked against test-pit data for the Mobil pulsed neutron porosity tool and was found to be very accurate. Results of the experimental validation and details of code performance are presented.

Usual Dietary Intakes: SAS Macros for Fitting Multivariate Measurement Error Models & Estimating Multivariate Usual Intake Distributions

Cancer.gov

The following SAS macros can be used to create a multivariate usual intake distribution for multiple dietary components that are consumed nearly every day or episodically. A SAS macro for performing balanced repeated replication (BRR) variance estimation is also included.

SPSS Macros for Assessing the Reliability and Agreement of Student Evaluations of Teaching

ERIC Educational Resources Information Center

Morley, Donald D.

2009-01-01

This article reports and demonstrates two SPSS macros for calculating Krippendorff's alpha and intraclass reliability coefficients in repetitive situations where numerous coefficients are needed. Specifically, the reported SPSS macros were used to evaluate the interrater agreement and reliability of student evaluations of teaching in thousands of…

On Language Management in Multinational Companies in the Czech Republic

ERIC Educational Resources Information Center

Nekvapil, Jiri; Nekula, Marek

2006-01-01

In this paper, we demonstrate the dialectical relationship between micro and macro language planning: macro planning influences micro planning and yet macro planning results (or should result) from micro planning. The relation between the two planning perspectives is illustrated within the framework of Language Management Theory (Jernudd &…

Why Macro Practice Matters

ERIC Educational Resources Information Center

Reisch, Michael

2016-01-01

This article asserts that macro practice is increasingly important in today's rapidly changing and complex practice environment. It briefly explores the history of macro practice in U.S. social work, summarizes its major contributions to the profession and to U.S. society, and provides some suggestions for how social work programs can expand…

A zwitterionic macro-crosslinker for durable non-fouling coatings.

PubMed

Wang, Wei; Lu, Yang; Xie, Jinbing; Zhu, Hui; Cao, Zhiqiang

2016-03-28

A novel zwitterionic macro-crosslinker was developed and applied to fabricate durable non-fouling coatings on a polyurethane substrate. The zwitterionic macro-crosslinker coating exhibited superior durability over the traditional brush polymer coating and was able to retain its non-fouling property even after weeks of shearing in flowing liquid.

Computer-Aided Modeling and Analysis of Power Processing Systems (CAMAPPS). Phase 1: Users handbook

NASA Technical Reports Server (NTRS)

Kim, S.; Lee, J.; Cho, B. H.; Lee, F. C.

1986-01-01

The EASY5 macro component models developed for the spacecraft power system simulation are described. A brief explanation about how to use the macro components with the EASY5 Standard Components to build a specific system is given through an example. The macro components are ordered according to the following functional group: converter power stage models, compensator models, current-feedback models, constant frequency control models, load models, solar array models, and shunt regulator models. Major equations, a circuit model, and a program listing are provided for each macro component.

Investigation on growth and macro-defects of Er3+-doped BaY2F8 laser crystal

NASA Astrophysics Data System (ADS)

Wang, Shuai; Ruan, Yongfeng; Tsuboi, Taiju; Zhang, Shouchao; Wang, Youfa; Tong, Hongshuang

2013-08-01

Large BaY2F8 and Er3+-doped BaY2F8 single crystals were grown by the temperature gradient method. Three kinds of macro-defects were found in BaY2F8 single crystals. These macro-defects include cracks, growth striations and straight pipes. The morphologies and distribution regularities of these macro-defects were observed and studied using a solid polarization microscope. The formation mechanisms and the methods of eliminating these defects were discussed.

At the intersection of micro and macro: opportunities and challenges for physician-patient communication research.

PubMed

Cline, Rebecca J Welch

2003-05-01

The health care relationship model is undergoing dramatic change. Micro-level communication patterns yield health care relationship models (e.g. paternalism, mutual participation, consumerism). At the same time, macro-level systems appear increasingly likely to influence the nature of micro-level interaction. The intersections of health care communication micro-level and macro-level phenomena provide important venues for research and interventions. This essay identifies theoretical premises regarding the relationships between communication and health-related behavior; explores three prominent and growing macro-level phenomena that observers argue likely influence the physical-patient relationship and communication therein: complementary and alternative medicine, the Internet, and direct-to-consumer advertising of prescription drugs; and offers a research agenda for exploring macro-level influences on micro-level physician-patient communication.

Electroanalytical sensing of chromium(III) and (VI) utilising gold screen printed macro electrodes.

PubMed

Metters, Jonathan P; Kadara, Rashid O; Banks, Craig E

2012-02-21

We report the fabrication of gold screen printed macro electrodes which are electrochemically characterised and contrasted to polycrystalline gold macroelectrodes with their potential analytical application towards the sensing of chromium(III) and (VI) critically explored. It is found that while these gold screen printed macro electrodes have electrode kinetics typically one order of magnitude lower than polycrystalline gold macroelectrodes as is measured via a standard redox probe, in terms of analytical sensing, these gold screen printed macro electrodes mimic polycrystalline gold in terms of their analytical performance towards the sensing of chromium(III) and (VI), whilst boasting additional advantages over the macro electrode due to their disposable one-shot nature and the ease of mass production. An additional advantage of these gold screen printed macro electrodes compared to polycrystalline gold is the alleviation of the requirement to potential cycle the latter to form the required gold oxide which aids in the simplification of the analytical protocol. We demonstrate that gold screen printed macro electrodes allow the low micro-molar sensing of chromium(VI) in aqueous solutions over the range 10 to 1600 μM with a limit of detection (3σ) of 4.4 μM. The feasibility of the analytical protocol is also tested through chromium(VI) detection in environmental samples.

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

Rohe, Daniel Peter

Sandia National Laboratories has recently purchased a Polytec 3D Scanning Laser Doppler Vibrometer for vibration measurement. This device has proven to be a very nice tool for making vibration measurements, and has a number of advantages over traditional sensors such as accelerometers. The non-contact nature of the laser vibrometer means there is no mass loading due to measuring the response. Additionally, the laser scanning heads can position the laser spot much more quickly and accurately than placing an accelerometer or performing a roving hammer impact. The disadvantage of the system is that a significant amount of time must be investedmore » to align the lasers with each other and the part so that the laser spots can be accurately positioned. The Polytec software includes a number of nice tools to aid in this procedure; however, certain portions are still tedious. Luckily, the Polytec software is readily extensible by programming macros for the system, so tedious portions of the procedure can be made easier by automating the process. The Polytec Software includes a WinWrap (similar to Visual Basic) editor and interface to run macros written in that programming language. The author, however, is much more proficient in Python, and the latter also has a much larger set of libraries that can be used to create very complex macros, while taking advantage of Python’s inherent readability and maintainability.« less

From single fiber to macro-level mechanics: A structural finite-element model for elastomeric fibrous biomaterials.

PubMed

D'Amore, Antonio; Amoroso, Nicholas; Gottardi, Riccardo; Hobson, Christopher; Carruthers, Christopher; Watkins, Simon; Wagner, William R; Sacks, Michael S

2014-11-01

In the present work, we demonstrate that the mesoscopic in-plane mechanical behavior of membrane elastomeric scaffolds can be simulated by replication of actual quantified fibrous geometries. Elastomeric electrospun polyurethane (ES-PEUU) scaffolds, with and without particulate inclusions, were utilized. Simulations were developed from experimentally-derived fiber network geometries, based on a range of scaffold isotropic and anisotropic behaviors. These were chosen to evaluate the effects on macro-mechanics based on measurable geometric parameters such as fiber intersections, connectivity, orientation, and diameter. Simulations were conducted with only the fiber material model parameters adjusted to match the macro-level mechanical test data. Fiber model validation was performed at the microscopic level by individual fiber mechanical tests using AFM. Results demonstrated very good agreement to the experimental data, and revealed the formation of extended preferential fiber orientations spanning the entire model space. We speculate that these emergent structures may be responsible for the tissue-like macroscale behaviors observed in electrospun scaffolds. To conclude, the modeling approach has implications for (1) gaining insight on the intricate relationship between fabrication variables, structure, and mechanics to manufacture more functional devices/materials, (2) elucidating the effects of cell or particulate inclusions on global construct mechanics, and (3) fabricating better performing tissue surrogates that could recapitulate native tissue mechanics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Predict drug permeability to blood–brain-barrier from clinical phenotypes: drug side effects and drug indications

PubMed Central

Gao, Zhen; Chen, Yang; Cai, Xiaoshu; Xu, Rong

2017-01-01

Abstract Motivation: Blood–Brain-Barrier (BBB) is a rigorous permeability barrier for maintaining homeostasis of Central Nervous System (CNS). Determination of compound’s permeability to BBB is prerequisite in CNS drug discovery. Existing computational methods usually predict drug BBB permeability from chemical structure and they generally apply to small compounds passing BBB through passive diffusion. As abundant information on drug side effects and indications has been recorded over time through extensive clinical usage, we aim to explore BBB permeability prediction from a new angle and introduce a novel approach to predict BBB permeability from drug clinical phenotypes (drug side effects and drug indications). This method can apply to both small compounds and macro-molecules penetrating BBB through various mechanisms besides passive diffusion. Results: We composed a training dataset of 213 drugs with known brain and blood steady-state concentrations ratio and extracted their side effects and indications as features. Next, we trained SVM models with polynomial kernel and obtained accuracy of 76.0%, AUC 0.739, and F1 score (macro weighted) 0.760 with Monte Carlo cross validation. The independent test accuracy was 68.3%, AUC 0.692, F1 score 0.676. When both chemical features and clinical phenotypes were available, combining the two types of features achieved significantly better performance than chemical feature based approach (accuracy 85.5% versus 72.9%, AUC 0.854 versus 0.733, F1 score 0.854 versus 0.725; P < e−90). We also conducted de novo prediction and identified 110 drugs in SIDER database having the potential to penetrate BBB, which could serve as start point for CNS drug repositioning research. Availability and Implementation: https://github.com/bioinformatics-gao/CASE-BBB-prediction-Data Contact: rxx@case.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27993785

Regulation of neural macroRNAs by the transcriptional repressor REST

PubMed Central

Johnson, Rory; Teh, Christina Hui-Leng; Jia, Hui; Vanisri, Ravi Raj; Pandey, Tridansh; Lu, Zhong-Hao; Buckley, Noel J.; Stanton, Lawrence W.; Lipovich, Leonard

2009-01-01

The essential transcriptional repressor REST (repressor element 1-silencing transcription factor) plays central roles in development and human disease by regulating a large cohort of neural genes. These have conventionally fallen into the class of known, protein-coding genes; recently, however, several noncoding microRNA genes were identified as REST targets. Given the widespread transcription of messenger RNA-like, noncoding RNAs (“macroRNAs”), some of which are functional and implicated in disease in mammalian genomes, we sought to determine whether this class of noncoding RNAs can also be regulated by REST. By applying a new, unbiased target gene annotation pipeline to computationally discovered REST binding sites, we find that 23% of mammalian REST genomic binding sites are within 10 kb of a macroRNA gene. These putative target genes were overlooked by previous studies. Focusing on a set of 18 candidate macroRNA targets from mouse, we experimentally demonstrate that two are regulated by REST in neural stem cells. Flanking protein-coding genes are, at most, weakly repressed, suggesting specific targeting of the macroRNAs by REST. Similar to the majority of known REST target genes, both of these macroRNAs are induced during nervous system development and have neurally restricted expression profiles in adult mouse. We observe a similar phenomenon in human: the DiGeorge syndrome-associated noncoding RNA, DGCR5, is repressed by REST through a proximal upstream binding site. Therefore neural macroRNAs represent an additional component of the REST regulatory network. These macroRNAs are new candidates for understanding the role of REST in neuronal development, neurodegeneration, and cancer. PMID:19050060

Regulation of neural macroRNAs by the transcriptional repressor REST.

PubMed

Johnson, Rory; Teh, Christina Hui-Leng; Jia, Hui; Vanisri, Ravi Raj; Pandey, Tridansh; Lu, Zhong-Hao; Buckley, Noel J; Stanton, Lawrence W; Lipovich, Leonard

2009-01-01

The essential transcriptional repressor REST (repressor element 1-silencing transcription factor) plays central roles in development and human disease by regulating a large cohort of neural genes. These have conventionally fallen into the class of known, protein-coding genes; recently, however, several noncoding microRNA genes were identified as REST targets. Given the widespread transcription of messenger RNA-like, noncoding RNAs ("macroRNAs"), some of which are functional and implicated in disease in mammalian genomes, we sought to determine whether this class of noncoding RNAs can also be regulated by REST. By applying a new, unbiased target gene annotation pipeline to computationally discovered REST binding sites, we find that 23% of mammalian REST genomic binding sites are within 10 kb of a macroRNA gene. These putative target genes were overlooked by previous studies. Focusing on a set of 18 candidate macroRNA targets from mouse, we experimentally demonstrate that two are regulated by REST in neural stem cells. Flanking protein-coding genes are, at most, weakly repressed, suggesting specific targeting of the macroRNAs by REST. Similar to the majority of known REST target genes, both of these macroRNAs are induced during nervous system development and have neurally restricted expression profiles in adult mouse. We observe a similar phenomenon in human: the DiGeorge syndrome-associated noncoding RNA, DGCR5, is repressed by REST through a proximal upstream binding site. Therefore neural macroRNAs represent an additional component of the REST regulatory network. These macroRNAs are new candidates for understanding the role of REST in neuronal development, neurodegeneration, and cancer.

Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes.

PubMed

Zellmer, Erik R; MacEwan, Matthew R; Moran, Daniel W

2018-04-01

Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. Recruitment thresholds of individual regenerated fibers with diameters  >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90-140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.

Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes

NASA Astrophysics Data System (ADS)

Zellmer, Erik R.; MacEwan, Matthew R.; Moran, Daniel W.

2018-04-01

Objective. Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). Approach. A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. Main results. Recruitment thresholds of individual regenerated fibers with diameters  >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90-140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. Significance. Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.

Systemic Integration and Macro Steering

ERIC Educational Resources Information Center

Bleiklie, Ivar

2007-01-01

The article deals with the development of national higher education systems and the emergence of macro steering in Europe and to some extent in the USA. It is based on the assumption that this process of integration of higher education systems through macro steering will increasingly be felt as a forceful influence on higher education. Integration…

Teaching Note--Incorporating Social Innovation Content into Macro Social Work Education

ERIC Educational Resources Information Center

Pitt-Catsouphes, Marcie; Cosner Berzin, Stephanie

2015-01-01

The practice of social innovation offers promising approaches for addressing social issues. Although many social innovation strategies are congruent with macro social work theory and practice, some of the insights and tactics that have emerged in the social innovation field have the potential to strengthen current macro practice. Based on our…

Micro-Macro Compatibility: When Does a Complex Systems Approach Strongly Benefit Science Learning?

ERIC Educational Resources Information Center

Samon, Sigal; Levy, Sharona T.

2017-01-01

The study explores how a complexity approach empowers science learning. A complexity approach represents systems as many interacting entities. The construct of micro-macro compatibility is introduced, the degree of similarity between behaviors at the micro- and macro-levels of the system. Seventh-grade students' learning about gases was studied…

Food/Hunger Macro-Analysis Seminar. A Do-It-Yourself Manual for College Courses and Action Groups.

ERIC Educational Resources Information Center

Moyer, William; Thorne, Erika

This guide describes a fifteen-week macro-analysis seminar about food production, distribution, and consumption on international, national, and local levels. The macro-analysis approach emphasizes the interrelatedness of all parts of the food/hunger issue; therefore the seminar also addresses escalating military expenditures, widening poverty, and…

Development of Hollow Steel Ball Macro-Encapsulated PCM for Thermal Energy Storage Concrete

PubMed Central

Dong, Zhijun; Cui, Hongzhi; Tang, Waiching; Chen, Dazhu; Wen, Haibo

2016-01-01

The application of thermal energy storage with phase change materials (PCMs) for energy efficiency of buildings grew rapidly in the last few years. In this research, octadecane paraffin was served as a PCM, and a structural concrete with the function of indoor temperature control was developed by using a macro-encapsulated PCM hollow steel ball (HSB). The macro-encapsulated PCM-HSB was prepared by incorporation of octadecane into HSBs through vacuum impregnation. Test results showed that the maximum percentage of octadecane carried by HSBs was 80.3% by mass. The macro-encapsulated PCM-HSB has a latent heat storage capacity as high as 200.5 J/g. The compressive strength of concrete with macro-encapsulated PCM-HSB at 28 days ranged from 22 to 40 MPa. The indoor thermal performance test revealed that concrete with macro-encapsulated octadecane-HSB was capable of reducing the peak indoor air temperature and the fluctuation of indoor temperature. It can be very effective in transferring the heating and cooling loads away from the peak demand times. PMID:28787859

Development of Hollow Steel Ball Macro-Encapsulated PCM for Thermal Energy Storage Concrete.

PubMed

Dong, Zhijun; Cui, Hongzhi; Tang, Waiching; Chen, Dazhu; Wen, Haibo

2016-01-19

The application of thermal energy storage with phase change materials (PCMs) for energy efficiency of buildings grew rapidly in the last few years. In this research, octadecane paraffin was served as a PCM, and a structural concrete with the function of indoor temperature control was developed by using a macro-encapsulated PCM hollow steel ball (HSB). The macro-encapsulated PCM-HSB was prepared by incorporation of octadecane into HSBs through vacuum impregnation. Test results showed that the maximum percentage of octadecane carried by HSBs was 80.3% by mass. The macro-encapsulated PCM-HSB has a latent heat storage capacity as high as 200.5 J/g. The compressive strength of concrete with macro-encapsulated PCM-HSB at 28 days ranged from 22 to 40 MPa. The indoor thermal performance test revealed that concrete with macro-encapsulated octadecane-HSB was capable of reducing the peak indoor air temperature and the fluctuation of indoor temperature. It can be very effective in transferring the heating and cooling loads away from the peak demand times.

[Monitoring "green tide" in the Yellow Sea and the East China Sea using multi-temporal and multi-source remote sensing images].

PubMed

Xing, Qian-Guo; Zheng, Xiang-Yang; Shi, Ping; Hao, Jia-Jia; Yu, Ding-Feng; Liang, Shou-Zhen; Liu, Dong-Yan; Zhang, Yuan-Zhi

2011-06-01

Landsat-TM (Theme Mapper) and EOS (Earth Observing System)-MODIS (MODerate resolution Imaging Spectrora-diometer) Terra/Aqua images were used to monitor the macro-algae (Ulva prolifera) bloom since 2007 at the Yellow Sea and the East China Sea. At the turbid waters of Northern Jiangsu Shoal, there is strong spectral mixing behavior, and satellite images with finer spatical resolution are more effective in detection of macro-algae patches. Macro-algae patches were detected by the Landsat images for the first time at the Sheyang estuary where is dominated by very turbid waters. The MODIS images showed that the macro-algae from the turbid waters near the Northern Jiangsu Shoal drifted southwardly in the early of May and affected the East China Sea waters; with the strengthening east-asian Summer Monsoon, macro-algae patches mainly drifted in a northward path which was mostly observed at the Yellow Sea. Macro-algae patches were also found to drift eastwardly towards the Korea Peninsular, which are supposed to be driven by the sea surface wind.

Structural Characterization of the Histone Variant macroH2A

PubMed Central

Chakravarthy, Srinivas; Gundimella, Sampath Kumar Y.; Caron, Cecile; Perche, Pierre-Yves; Pehrson, John R.; Khochbin, Saadi; Luger, Karolin

2005-01-01

macroH2A is an H2A variant with a highly unusual structural organization. It has a C-terminal domain connected to the N-terminal histone domain by a linker. Crystallographic and biochemical studies show that changes in the L1 loop in the histone fold region of macroH2A impact the structure and potentially the function of nucleosomes. The 1.6-Å X-ray structure of the nonhistone region reveals an α/β fold which has previously been found in a functionally diverse group of proteins. This region associates with histone deacetylases and affects the acetylation status of nucleosomes containing macroH2A. Thus, the unusual domain structure of macroH2A integrates independent functions that are instrumental in establishing a structurally and functionally unique chromatin domain. PMID:16107708

Estimating a Noncompensatory IRT Model Using Metropolis within Gibbs Sampling

ERIC Educational Resources Information Center

Babcock, Ben

2011-01-01

Relatively little research has been conducted with the noncompensatory class of multidimensional item response theory (MIRT) models. A Monte Carlo simulation study was conducted exploring the estimation of a two-parameter noncompensatory item response theory (IRT) model. The estimation method used was a Metropolis-Hastings within Gibbs algorithm…

Reliability of Test Scores in Nonparametric Item Response Theory.

ERIC Educational Resources Information Center

Sijtsma, Klaas; Molenaar, Ivo W.

1987-01-01

Three methods for estimating reliability are studied within the context of nonparametric item response theory. Two were proposed originally by Mokken and a third is developed in this paper. Using a Monte Carlo strategy, these three estimation methods are compared with four "classical" lower bounds to reliability. (Author/JAZ)

Different Approaches to Covariate Inclusion in the Mixture Rasch Model

ERIC Educational Resources Information Center

Li, Tongyun; Jiao, Hong; Macready, George B.

2016-01-01

The present study investigates different approaches to adding covariates and the impact in fitting mixture item response theory models. Mixture item response theory models serve as an important methodology for tackling several psychometric issues in test development, including the detection of latent differential item functioning. A Monte Carlo…

Mentat: An object-oriented macro data flow system

NASA Technical Reports Server (NTRS)

Grimshaw, Andrew S.; Liu, Jane W. S.

1988-01-01

Mentat, an object-oriented macro data flow system designed to facilitate parallelism in distributed systems, is presented. The macro data flow model is a model of computation similar to the data flow model with two principal differences: the computational complexity of the actors is much greater than in traditional data flow systems, and there are persistent actors that maintain state information between executions. Mentat is a system that combines the object-oriented programming paradigm and the macro data flow model of computation. Mentat programs use a dynamic structure called a future list to represent the future of computations.

Consequences of Ignoring Guessing when Estimating the Latent Density in Item Response Theory

ERIC Educational Resources Information Center

Woods, Carol M.

2008-01-01

In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters. In extant Monte Carlo evaluations of RC-IRT, the item response function (IRF) used to fit the data is the same one used to generate the data. The present simulation study examines RC-IRT when the IRF is imperfectly…

Monte Carlo modeling of ion chamber performance using MCNP.

PubMed

Wallace, J D

2012-12-01

Ion Chambers have a generally flat energy response with some deviations at very low (<100 keV) and very high (>2 MeV) energies. Some improvements in the low energy response can be achieved through use of high atomic number gases, such as argon and xenon, and higher chamber pressures. This work looks at the energy response of high pressure xenon-filled ion chambers using the MCNP Monte Carlo package to develop geometric models of a commercially available high pressure ion chamber (HPIC). The use of the F6 tally as an estimator of the energy deposited in a region of interest per unit mass, and the underlying assumptions associated with its use are described. The effect of gas composition, chamber gas pressure, chamber wall thickness, and chamber holder wall thicknesses on energy response are investigated and reported. The predicted energy response curve for the HPIC was found to be similar to that reported by other investigators. These investigations indicate that improvements to flatten the overall energy response of the HPIC down to 70 keV could be achieved through use of 3 mm-thick stainless steel walls for the ion chamber.

Interactions between macro-algal mats and invertebrates in the Ythan estuary, Aberdeenshire, Scotland

NASA Astrophysics Data System (ADS)

Raffaelli, D.

2000-07-01

Blooms of opportunistic green macro-algae are a common feature of coastal areas and their effects on mudflat invertebrates can be dramatic. On the Ythan estuary, Aberdeenshire, Scotland, we have carried out a number of manipulative field experiments designed to evaluate the effects on invertebrates of different species of macro-algae with contrasting ecologies, and the effects of invertebrates on the development of the blooms. Macro-algal mats were found to have dramatic nega- tive effects on the density of the amphipod Corophium volutator, with higher algal biomasses having greater impact. The mechanism for this interaction seems to be interference by the algal filaments with the feeding behaviour of the amphipod. In contrast, the polychaete Capitella spp. increases in abundance under macro-algal mats due to enrichment of the sediment with organic material. These two interactions are seen at all scales, in areas of less than 1 m2 to the scale of the entire estuary, irrespective of the species composition of the macro- algal mats. Bioturbation by Corophium and grazing by the snail Hydrobia ulvae had little effect on macro-algal biomass, but there were less algae when the polychaete Nereis diversicolor was present. The most significant interaction in this system is the pronounced negative impact of algal mats on the abundance of Corophium, probably the most important invertebrate species in the diets of the estuary's shorebirds, fish and epibenthic crustaceans.

Accurate condensed history Monte Carlo simulation of electron transport. II. Application to ion chamber response simulations.

PubMed

Kawrakow, I

2000-03-01

In this report the condensed history Monte Carlo simulation of electron transport and its application to the calculation of ion chamber response is discussed. It is shown that the strong step-size dependencies and lack of convergence to the correct answer previously observed are the combined effect of the following artifacts caused by the EGS4/PRESTA implementation of the condensed history technique: dose underprediction due to PRESTA'S pathlength correction and lateral correlation algorithm; dose overprediction due to the boundary crossing algorithm; dose overprediction due to the breakdown of the fictitious cross section method for sampling distances between discrete interaction and the inaccurate evaluation of energy-dependent quantities. These artifacts are now understood quantitatively and analytical expressions for their effect are given.

Automating the Fireshed Assessment Process with ArcGIS

Treesearch

Alan Ager; Klaus Barber

2006-01-01

A library of macros was developed to automate the Fireshed process within ArcGIS. The macros link a number of vegetation simulation and wildfire behavior models (FVS, SVS, FARSITE, and FlamMap) with ESRI geodatabases, desktop software (Access, Excel), and ArcGIS. The macros provide for (1) an interactive linkage between digital imagery, vegetation data, FVS-FFE, and...

A Macro-Micro-Symbolic Teaching to Promote Relational Understanding of Chemical Reactions

ERIC Educational Resources Information Center

Jaber, Lama Ziad; Boujaoude, Saouma

2012-01-01

The purpose of this research is threefold: (1) to identify the difficulties that Grade 10 students in a Lebanese school have that hinder their conceptual understanding at the micro-macro-symbolic interface in chemistry, (2) to investigate the effect of a macro-micro-symbolic teaching approach on students' relational understanding of chemical…

Verification of unfold error estimates in the UFO code

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

Fehl, D.L.; Biggs, F.

Spectral unfolding is an inverse mathematical operation which attempts to obtain spectral source information from a set of tabulated response functions and data measurements. Several unfold algorithms have appeared over the past 30 years; among them is the UFO (UnFold Operator) code. In addition to an unfolded spectrum, UFO also estimates the unfold uncertainty (error) induced by running the code in a Monte Carlo fashion with prescribed data distributions (Gaussian deviates). In the problem studied, data were simulated from an arbitrarily chosen blackbody spectrum (10 keV) and a set of overlapping response functions. The data were assumed to have anmore » imprecision of 5% (standard deviation). 100 random data sets were generated. The built-in estimate of unfold uncertainty agreed with the Monte Carlo estimate to within the statistical resolution of this relatively small sample size (95% confidence level). A possible 10% bias between the two methods was unresolved. The Monte Carlo technique is also useful in underdetemined problems, for which the error matrix method does not apply. UFO has been applied to the diagnosis of low energy x rays emitted by Z-Pinch and ion-beam driven hohlraums.« less

Monte Carlo track structure for radiation biology and space applications

NASA Technical Reports Server (NTRS)

Nikjoo, H.; Uehara, S.; Khvostunov, I. G.; Cucinotta, F. A.; Wilson, W. E.; Goodhead, D. T.

2001-01-01

Over the past two decades event by event Monte Carlo track structure codes have increasingly been used for biophysical modelling and radiotherapy. Advent of these codes has helped to shed light on many aspects of microdosimetry and mechanism of damage by ionising radiation in the cell. These codes have continuously been modified to include new improved cross sections and computational techniques. This paper provides a summary of input data for ionizations, excitations and elastic scattering cross sections for event by event Monte Carlo track structure simulations for electrons and ions in the form of parametric equations, which makes it easy to reproduce the data. Stopping power and radial distribution of dose are presented for ions and compared with experimental data. A model is described for simulation of full slowing down of proton tracks in water in the range 1 keV to 1 MeV. Modelling and calculations are presented for the response of a TEPC proportional counter irradiated with 5 MeV alpha-particles. Distributions are presented for the wall and wall-less counters. Data shows contribution of indirect effects to the lineal energy distribution for the wall counters responses even at such a low ion energy.

Comparison of Measured Leakage Current Distributions with Calculated Damage Energy Distributions in HgCdTe

NASA Technical Reports Server (NTRS)

Marshall, C. J.; Ladbury, R.; Marshall, P. W.; Reed, R. A.; Howe, C.; Weller, B.; Mendenhall, M.; Waczynski, A.; Jordan, T. M.; Fodness, B.

2006-01-01

This paper presents a combined Monte Carlo and analytic approach to the calculation of the pixel-to-pixel distribution of proton-induced damage in a HgCdTe sensor array and compares the results to measured dark current distributions after damage by 63 MeV protons. The moments of the Coulombic, nuclear elastic and nuclear inelastic damage distribution were extracted from Monte Carlo simulations and combined to form a damage distribution using the analytic techniques first described in [I]. The calculations show that the high energy recoils from the nuclear inelastic reactions (calculated using the Monte Car10 code MCNPX [2]) produce a pronounced skewing of the damage energy distribution. The nuclear elastic component (also calculated using the MCNPX) has a negligible effect on the shape of the damage distribution. The Coulombic contribution was calculated using MRED [3,4], a Geant4 [4,5] application. The comparison with the dark current distribution strongly suggests that mechanisms which are not linearly correlated with nonionizing damage produced according to collision kinematics are responsible for the observed dark current increases. This has important implications for the process of predicting the on-orbit dark current response of the HgCdTe sensor array.

Monte Carlo simulations support non-Cerenkov radioluminescence production in tissue

NASA Astrophysics Data System (ADS)

Ackerman, Nicole L.; Boschi, Federico; Spinelli, Antonello E.

2017-08-01

There is experimental evidence for the production of non-Cerenkov radioluminescence in a variety of materials, including tissue. We constructed a Geant4 Monte Carlo simulation of the radiation from P32 and Tc99m interacting in chicken breast and used experimental imaging data to model a scintillation-like emission. The same radioluminescence spectrum is visible from both isotopes and cannot otherwise be explained through fluorescence or filter miscalibration. We conclude that chicken breast has a near-infrared scintillation-like response with a light yield three orders of magnitude smaller than BGO.

Metrics for Diagnosing Undersampling in Monte Carlo Tally Estimates

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

Perfetti, Christopher M.; Rearden, Bradley T.

This study explored the potential of using Markov chain convergence diagnostics to predict the prevalence and magnitude of biases due to undersampling in Monte Carlo eigenvalue and flux tally estimates. Five metrics were applied to two models of pressurized water reactor fuel assemblies and their potential for identifying undersampling biases was evaluated by comparing the calculated test metrics with known biases in the tallies. Three of the five undersampling metrics showed the potential to accurately predict the behavior of undersampling biases in the responses examined in this study.

Influence of Secondary Cooling Mode on Solidification Structure and Macro-segregation Behavior for High-carbon Continuous Casting Bloom

NASA Astrophysics Data System (ADS)

Dou, Kun; Yang, Zhenguo; Liu, Qing; Huang, Yunhua; Dong, Hongbiao

2017-07-01

A cellular automaton-finite element coupling model for high-carbon continuously cast bloom of GCr15 steel is established to simulate the solidification structure and to investigate the influence of different secondary cooling modes on characteristic parameters such as equiaxed crystal ratio, grain size and secondary dendrite arm spacing, in which the effect of phase transformation and electromagnetic stirring is taken into consideration. On this basis, evolution of carbon macro-segregation for GCr15 steel bloom is researched correspondingly via industrial tests. Based on above analysis, the relationship among secondary cooling modes, characteristic parameters for solidification structure as well as carbon macro-segregation is illustrated to obtain optimum secondary cooling strategy and alleviate carbon macro-segregation degree for GCr15 steel bloom in continuous casting process. The evaluating method for element macro-segregation is applicable in various steel types.

In-Situ Ultra Low Frequency Poroelastic Response of a Natural Macro-Fracture

NASA Astrophysics Data System (ADS)

Guglielmi, Y.; Cappa, F.; Rutqvist, J.; Tsang, C.; Gaffet, S.

2008-12-01

The seismic visibility of macro-fractures filled with fluids is a central problem in the exploration of thermo- hydro-mechanical and chemical processes that occur in Earth' s subsurface. Most studies have been concerned (1) with cracks of a small size relative to the seismic wavelength (2) with "core-sized" samples of single macro-fractures. In comparison, in-situ studies of macro-fractures are very rare and no real estimate is made of the relevance of this convenient "core-sized" data to in-situ reservoirs in general. In this study, we present a new experimental approach to in-situ characterize mechanical and hydraulic properties of fractures using the innovative HPPP protocol. This protocol allows simultaneous high-frequency (120.2 Hz) sampling of normal displacement and fluid pressure in a borehole intersecting the fracture. We show preliminary results conducted in a single fracture vertically embedded in a carbonate reservoir that contains 3 sets of macro-fractures with an average 2m spacing. Two HPPP probes were set, spaced one meter vertically in the fracture. Two types of ULF seismic sources are applied: a fluid pressure pulse injected in the fracture and a hammer hit at a point located 5m far from the fracture plane. There is a highly non-linear variation of fracture normal displacement-versus- fluid pressure as a function of frequency, the higher the frequency, the lower the displacement spectral amplitude is. The pressure pulse and the hammer hit allow exploring the fracture poroelastic response in the [0 - 3Hz] frequency range. The fracture plays the role of a "low-pass" filter for fluid pressure waves; only a quasi-static pressure signal being registered at the receiver. The displacement wave propagation is more complex resulting in uncoupled quasi-static-pressure-2Hz-deformation signals at the receiver. For low magnitude seismic sources (low amplitude pulse and seismic wave), the fracture natural resonance is amplified resulting in separate signals power spectral peaks. When fluid pressure is enough increased, hydraulic diffusion takes place at frequencies lower than 1.2 Hz. Poroelastic effects related to static hydraulic diffusion and to wave propagation were described separately using a linear elastic model where the fracture was treated as a displacement discontinuity across which stresses are continuous but displacement are discontinuous. It appears that the dynamic fracture normal stiffness at 2 to 3 Hz is a factor of 2.8 higher than the static stiffness although the fracture displays a high hydraulic aperture of 10-4 m. This surprising result is related to a high heterogeneity of the fracture channel network with a large porosity/permeability contrast that does not allow fluid displacement under dynamic loading. The HPPP approach appears as a possibility to in-situ characterize such fractures static to seismic poroelastic heterogeneous properties.

Hybrid Monte Carlo/deterministic methods for radiation shielding problems

NASA Astrophysics Data System (ADS)

Becker, Troy L.

For the past few decades, the most common type of deep-penetration (shielding) problem simulated using Monte Carlo methods has been the source-detector problem, in which a response is calculated at a single location in space. Traditionally, the nonanalog Monte Carlo methods used to solve these problems have required significant user input to generate and sufficiently optimize the biasing parameters necessary to obtain a statistically reliable solution. It has been demonstrated that this laborious task can be replaced by automated processes that rely on a deterministic adjoint solution to set the biasing parameters---the so-called hybrid methods. The increase in computational power over recent years has also led to interest in obtaining the solution in a region of space much larger than a point detector. In this thesis, we propose two methods for solving problems ranging from source-detector problems to more global calculations---weight windows and the Transform approach. These techniques employ sonic of the same biasing elements that have been used previously; however, the fundamental difference is that here the biasing techniques are used as elements of a comprehensive tool set to distribute Monte Carlo particles in a user-specified way. The weight window achieves the user-specified Monte Carlo particle distribution by imposing a particular weight window on the system, without altering the particle physics. The Transform approach introduces a transform into the neutron transport equation, which results in a complete modification of the particle physics to produce the user-specified Monte Carlo distribution. These methods are tested in a three-dimensional multigroup Monte Carlo code. For a basic shielding problem and a more realistic one, these methods adequately solved source-detector problems and more global calculations. Furthermore, they confirmed that theoretical Monte Carlo particle distributions correspond to the simulated ones, implying that these methods can be used to achieve user-specified Monte Carlo distributions. Overall, the Transform approach performed more efficiently than the weight window methods, but it performed much more efficiently for source-detector problems than for global problems.

The Elicitor Protein AsES Induces a Systemic Acquired Resistance Response Accompanied by Systemic Microbursts and Micro-Hypersensitive Responses in Fragaria ananassa.

PubMed

Hael-Conrad, Verónica; Perato, Silvia Marisa; Arias, Marta Eugenia; Martínez-Zamora, Martín Gustavo; Di Peto, Pía de Los Ángeles; Martos, Gustavo Gabriel; Castagnaro, Atilio Pedro; Díaz-Ricci, Juan Carlos; Chalfoun, Nadia Regina

2018-01-01

The elicitor AsES (Acremonium strictum elicitor subtilisin) is a 34-kDa subtilisin-like protein secreted by the opportunistic fungus Acremonium strictum. AsES activates innate immunity and confers resistance against anthracnose and gray mold diseases in strawberry plants (Fragaria × ananassa Duch.) and the last disease also in Arabidopsis. In the present work, we show that, upon AsES recognition, a cascade of defense responses is activated, including: calcium influx, biphasic oxidative burst (O 2 ⋅- and H 2 O 2 ), hypersensitive cell-death response (HR), accumulation of autofluorescent compounds, cell-wall reinforcement with callose and lignin deposition, salicylic acid accumulation, and expression of defense-related genes, such as FaPR1, FaPG1, FaMYB30, FaRBOH-D, FaRBOH-F, FaCHI23, and FaFLS. All these responses occurred following a spatial and temporal program, first induced in infiltrated leaflets (local acquired resistance), spreading out to untreated lateral leaflets, and later, to distal leaves (systemic acquired resistance). After AsES treatment, macro-HR and macro-oxidative bursts were localized in infiltrated leaflets, while micro-HRs and microbursts occurred later in untreated leaves, being confined to a single cell or a cluster of a few epidermal cells that differentiated from the surrounding ones. The differentiated cells initiated a time-dependent series of physiological and anatomical changes, evolving to idioblasts accumulating H 2 O 2 and autofluorescent compounds that blast, delivering its content into surrounding cells. This kind of systemic cell-death process in plants is described for the first time in response to a single elicitor. All data presented in this study suggest that AsES has the potential to activate a wide spectrum of biochemical and molecular defense responses in F. ananassa that may explain the induced protection toward pathogens of opposite lifestyle, like hemibiotrophic and necrotrophic fungi.

A homogenized localizing gradient damage model with micro inertia effect

NASA Astrophysics Data System (ADS)

Wang, Zhao; Poh, Leong Hien

2018-07-01

The conventional gradient enhancement regularizes structural responses during material failure. However, it induces a spurious damage growth phenomenon, which is shown here to persist in dynamics. Similar issues were reported with the integral averaging approach. Consequently, the conventional nonlocal enhancement cannot adequately describe the dynamic fracture of quasi-brittle materials, particularly in the high strain rate regime, where a diffused damage profile precludes the development of closely spaced macrocracks. To this end, a homogenization theory is proposed to translate the micro processes onto the macro scale. Starting with simple elementary models at the micro scale to describe the fracture mechanisms, an additional kinematic field is introduced to capture the variations in deformation and velocity within a unit cell. An energetic equivalence between micro and macro is next imposed to ensure consistency at the two scales. The ensuing homogenized microforce balance resembles closely the conventional gradient expression, albeit with an interaction domain that decreases with damage, complemented by a micro inertia effect. Considering a direct single pressure bar example, the homogenized model is shown to resolve the non-physical responses obtained with conventional nonlocal enhancement. The predictive capability of the homogenized model is furthermore demonstrated by considering the spall tests of concrete, with good predictions on failure characteristics such as fragmentation profiles and dynamic tensile strengths, at three different loading rates.

Analysis of the Transitioning Opportunity for Non-Traditional Firms Under Other Transaction Authority

DTIC Science & Technology

2008-06-01

PESTEL Analysis PESTEL Analysis examines the general environment surrounding the defense industry in a macro perspective. Its focus is on six main...legislation (p. 575). C. STRATEGIC ANALYSIS OF THE MACRO ENVIRONMENT 1. Porter’s Five-Forces Model Analysis Porter’s Five-Forces Model is used to analyze...B. PREVIOUS ANALYSES.................................................................................9 C. STRATEGIC ANALYSIS OF THE MACRO

A Force-Controllable Macro-Micro Manipulator and its Application to Medical Robotics

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.; Uecker, Darrin R.; Wang, Yulun

1993-01-01

This paper describes an 8-degrees-of-freedom macro-micro robot. This robot is capable of performing tasks that require accurate force control, such as polishing, finishing, grinding, deburring, and cleaning. The design of the macro-micro mechanism, the control algorithms, and the hardware/sofware implemtation of the algotithms are described in this paper. Initial experimental results are reported.

Inequality in Participation in Adult Learning and Education (ALE): Effects of Micro- and Macro-Level Factors through a Comparative Study

ERIC Educational Resources Information Center

Lee, Jeongwoo

2017-01-01

The objectives of this dissertation include describing and analyzing the patterns of inequality in ALE participation at both the micro and macro levels. Special attention is paid to social origins of individual adults and their association with two groups of macro-level factors, social inequality (income, education, and skill inequality) and…

Why Are Macros Not Used? A Brief Review and an Approach for Improving Training

ERIC Educational Resources Information Center

Yechiam, Eldad

2006-01-01

Macros are programming scripts that can be generated by recording users' actions. It appears that despite their potential for reducing monotonous work, they are under-used by non-programmers. The present paper reviews the literature on the use of macros. Included is an original study that examines the effect of adding the "search and replace"…

The Micro and Macro Analysis of English and Arabic Religious Texts

ERIC Educational Resources Information Center

Al-Araji, Baida Faisal; Al-Azzawi, Sarab Khalil

2016-01-01

Religious discourse has been treated differently in various types of studies. In the present study, the English Biblical and Arabic Prophetic Hadiths will be tackled on two bases namely the micro and macro levels. In other words, the data will be analyzed at both micro and macro levels to maintain the organizational status of the religious texts.…

Modeling air concentration over macro roughness conditions by Artificial Intelligence techniques

NASA Astrophysics Data System (ADS)

Roshni, T.; Pagliara, S.

2018-05-01

Aeration is improved in rivers by the turbulence created in the flow over macro and intermediate roughness conditions. Macro and intermediate roughness flow conditions are generated by flows over block ramps or rock chutes. The measurements are taken in uniform flow region. Efficacy of soft computing methods in modeling hydraulic parameters are not common so far. In this study, modeling efficiencies of MPMR model and FFNN model are found for estimating the air concentration over block ramps under macro roughness conditions. The experimental data are used for training and testing phases. Potential capability of MPMR and FFNN model in estimating air concentration are proved through this study.

Managing protected health information in distributed research network environments: automated review to facilitate collaboration.

PubMed

Bredfeldt, Christine E; Butani, Amy; Padmanabhan, Sandhyasree; Hitz, Paul; Pardee, Roy

2013-03-22

Multi-site health sciences research is becoming more common, as it enables investigation of rare outcomes and diseases and new healthcare innovations. Multi-site research usually involves the transfer of large amounts of research data between collaborators, which increases the potential for accidental disclosures of protected health information (PHI). Standard protocols for preventing release of PHI are extremely vulnerable to human error, particularly when the shared data sets are large. To address this problem, we developed an automated program (SAS macro) to identify possible PHI in research data before it is transferred between research sites. The macro reviews all data in a designated directory to identify suspicious variable names and data patterns. The macro looks for variables that may contain personal identifiers such as medical record numbers and social security numbers. In addition, the macro identifies dates and numbers that may identify people who belong to small groups, who may be identifiable even in the absences of traditional identifiers. Evaluation of the macro on 100 sample research data sets indicated a recall of 0.98 and precision of 0.81. When implemented consistently, the macro has the potential to streamline the PHI review process and significantly reduce accidental PHI disclosures.

Optimization of healthcare supply chain in context of macro-ergonomics factors by a unique mathematical programming approach.

PubMed

Azadeh, A; Motevali Haghighi, S; Gaeini, Z; Shabanpour, N

2016-07-01

This study presents an integrated approach for analyzing the impact of macro-ergonomics factors in healthcare supply chain (HCSC) by data envelopment analysis (DEA). The case of this study is the supply chain (SC) of a real hospital. Thus, healthcare standards and macro-ergonomics factors are considered to be modeled by the mathematical programming approach. Over 28 subsidiary SC divisions with parallel missions and objectives are evaluated by analyzing inputs and outputs through DEA. Each division in this HCSC is considered as decision making unit (DMU). This approach can analyze the impact of macro-ergonomics factors on supply chain management (SCM) in healthcare sector. Also, this method ranks the relevant performance efficiencies of each HCSC. In this study by using proposed method, the most effective macro-ergonomics factor on HCSC is identified as "teamwork" issue. Also, this study would help managers to identify the areas of weaknesses in their SCM system and set improvement target plan for the related SCM system in healthcare industry. To the best of our knowledge, this is the first study for macro-ergonomics optimization of HCSC. Copyright © 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Research on Mechanisms and Controlling Methods of Macro Defects in TC4 Alloy Fabricated by Wire Additive Manufacturing.

PubMed

Ji, Lei; Lu, Jiping; Tang, Shuiyuan; Wu, Qianru; Wang, Jiachen; Ma, Shuyuan; Fan, Hongli; Liu, Changmeng

2018-06-28

Wire feeding additive manufacturing (WFAM) has broad application prospects because of its advantages of low cost and high efficiency. However, with the mode of lateral wire feeding, including wire and laser additive manufacturing, gas tungsten arc additive manufacturing etc., it is easy to generate macro defects on the surface of the components because of the anisotropy of melted wire, which limits the promotion and application of WFAM. In this work, gas tungsten arc additive manufacturing with lateral wire feeding is proposed to investigate the mechanisms of macro defects. The results illustrate that the defect forms mainly include side spatters, collapse, poor flatness, and unmelted wire. It was found that the heat input, layer thickness, tool path, and wire curvature can have an impact on the macro defects. Side spatters are the most serious defects, mainly because the droplets cannot be transferred to the center of the molten pool in the lateral wire feeding mode. This research indicates that the macro defects can be controlled by optimizing the process parameters. Finally, block parts without macro defects were fabricated, which is meaningful for the further application of WFAM.

On analyzing ordinal data when responses and covariates are both missing at random.

PubMed

Rana, Subrata; Roy, Surupa; Das, Kalyan

2016-08-01

In many occasions, particularly in biomedical studies, data are unavailable for some responses and covariates. This leads to biased inference in the analysis when a substantial proportion of responses or a covariate or both are missing. Except a few situations, methods for missing data have earlier been considered either for missing response or for missing covariates, but comparatively little attention has been directed to account for both missing responses and missing covariates, which is partly attributable to complexity in modeling and computation. This seems to be important as the precise impact of substantial missing data depends on the association between two missing data processes as well. The real difficulty arises when the responses are ordinal by nature. We develop a joint model to take into account simultaneously the association between the ordinal response variable and covariates and also that between the missing data indicators. Such a complex model has been analyzed here by using the Markov chain Monte Carlo approach and also by the Monte Carlo relative likelihood approach. Their performance on estimating the model parameters in finite samples have been looked into. We illustrate the application of these two methods using data from an orthodontic study. Analysis of such data provides some interesting information on human habit. © The Author(s) 2013.

Item Response Theory Equating Using Bayesian Informative Priors.

ERIC Educational Resources Information Center

de la Torre, Jimmy; Patz, Richard J.

This paper seeks to extend the application of Markov chain Monte Carlo (MCMC) methods in item response theory (IRT) to include the estimation of equating relationships along with the estimation of test item parameters. A method is proposed that incorporates estimation of the equating relationship in the item calibration phase. Item parameters from…

Evaluating Item Fit for Multidimensional Item Response Models

ERIC Educational Resources Information Center

Zhang, Bo; Stone, Clement A.

2008-01-01

This research examines the utility of the s-x[superscript 2] statistic proposed by Orlando and Thissen (2000) in evaluating item fit for multidimensional item response models. Monte Carlo simulation was conducted to investigate both the Type I error and statistical power of this fit statistic in analyzing two kinds of multidimensional test…

The Cherenkov Telescope Array production system for Monte Carlo simulations and analysis

NASA Astrophysics Data System (ADS)

Arrabito, L.; Bernloehr, K.; Bregeon, J.; Cumani, P.; Hassan, T.; Haupt, A.; Maier, G.; Moralejo, A.; Neyroud, N.; pre="for the"> CTA Consortium, DIRAC Consortium,

2017-10-01

The Cherenkov Telescope Array (CTA), an array of many tens of Imaging Atmospheric Cherenkov Telescopes deployed on an unprecedented scale, is the next-generation instrument in the field of very high energy gamma-ray astronomy. An average data stream of about 0.9 GB/s for about 1300 hours of observation per year is expected, therefore resulting in 4 PB of raw data per year and a total of 27 PB/year, including archive and data processing. The start of CTA operation is foreseen in 2018 and it will last about 30 years. The installation of the first telescopes in the two selected locations (Paranal, Chile and La Palma, Spain) will start in 2017. In order to select the best site candidate to host CTA telescopes (in the Northern and in the Southern hemispheres), massive Monte Carlo simulations have been performed since 2012. Once the two sites have been selected, we have started new Monte Carlo simulations to determine the optimal array layout with respect to the obtained sensitivity. Taking into account that CTA may be finally composed of 7 different telescope types coming in 3 different sizes, many different combinations of telescope position and multiplicity as a function of the telescope type have been proposed. This last Monte Carlo campaign represented a huge computational effort, since several hundreds of telescope positions have been simulated, while for future instrument response function simulations, only the operating telescopes will be considered. In particular, during the last 18 months, about 2 PB of Monte Carlo data have been produced and processed with different analysis chains, with a corresponding overall CPU consumption of about 125 M HS06 hours. In these proceedings, we describe the employed computing model, based on the use of grid resources, as well as the production system setup, which relies on the DIRAC interware. Finally, we present the envisaged evolutions of the CTA production system for the off-line data processing during CTA operations and the instrument response function simulations.

Monte Carlo Modeling of VLWIR HgCdTe Interdigitated Pixel Response

NASA Astrophysics Data System (ADS)

D'Souza, A. I.; Stapelbroek, M. G.; Wijewarnasuriya, P. S.

2010-07-01

Increasing very long-wave infrared (VLWIR, λ c ≈ 15 μm) pixel operability was approached by subdividing each pixel into four interdigitated subpixels. High response is maintained across the pixel, even if one or two interdigitated subpixels are deselected (turned off), because interdigitation provides that the preponderance of minority carriers photogenerated in the pixel are collected by the selected subpixels. Monte Carlo modeling of the photoresponse of the interdigitated subpixel simulates minority-carrier diffusion from carrier creation to recombination. Each carrier generated at an appropriately weighted random location is assigned an exponentially distributed random lifetime τ i, where < τ i> is the bulk minority-carrier lifetime. The minority carrier is allowed to diffuse for a short time d τ, and the fate of the carrier is decided from its present position and the boundary conditions, i.e., whether the carrier is absorbed in a junction, recombined at a surface, reflected from a surface, or recombined in the bulk because it lived for its designated lifetime. If nothing happens, the process is then repeated until one of the boundary conditions is attained. The next step is to go on to the next carrier and repeat the procedure for all the launches of minority carriers. For each minority carrier launched, the original location and boundary condition at fatality are recorded. An example of the results from Monte Carlo modeling is that, for a 20- μm diffusion length, the calculated quantum efficiency (QE) changed from 85% with no subpixels deselected, to 78% with one subpixel deselected, 67% with two subpixels deselected, and 48% with three subpixels deselected. Demonstration of the interdigitated pixel concept and verification of the Monte Carlo modeling utilized λ c(60 K) ≈ 15 μm HgCdTe pixels in a 96 × 96 array format. The measured collection efficiency for one, two, and three subelements selected, divided by the collection efficiency for all four subelements selected, matched that calculated using Monte Carlo modeling.

Monte Carlo method for photon heating using temperature-dependent optical properties.

PubMed

Slade, Adam Broadbent; Aguilar, Guillermo

2015-02-01

The Monte Carlo method for photon transport is often used to predict the volumetric heating that an optical source will induce inside a tissue or material. This method relies on constant (with respect to temperature) optical properties, specifically the coefficients of scattering and absorption. In reality, optical coefficients are typically temperature-dependent, leading to error in simulation results. The purpose of this study is to develop a method that can incorporate variable properties and accurately simulate systems where the temperature will greatly vary, such as in the case of laser-thawing of frozen tissues. A numerical simulation was developed that utilizes the Monte Carlo method for photon transport to simulate the thermal response of a system that allows temperature-dependent optical and thermal properties. This was done by combining traditional Monte Carlo photon transport with a heat transfer simulation to provide a feedback loop that selects local properties based on current temperatures, for each moment in time. Additionally, photon steps are segmented to accurately obtain path lengths within a homogenous (but not isothermal) material. Validation of the simulation was done using comparisons to established Monte Carlo simulations using constant properties, and a comparison to the Beer-Lambert law for temperature-variable properties. The simulation is able to accurately predict the thermal response of a system whose properties can vary with temperature. The difference in results between variable-property and constant property methods for the representative system of laser-heated silicon can become larger than 100K. This simulation will return more accurate results of optical irradiation absorption in a material which undergoes a large change in temperature. This increased accuracy in simulated results leads to better thermal predictions in living tissues and can provide enhanced planning and improved experimental and procedural outcomes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Micro and Macro Segregation in Alloys Solidifying with Equiaxed Morphology

NASA Technical Reports Server (NTRS)

Stefanescu, Doru M.; Curreri, Peter A.; Leon-Torres, Jose; Sen, Subhayu

1996-01-01

To understand macro segregation formation in Al-Cu alloys, experiments were run under terrestrial gravity (1g) and under low gravity during parabolic flights (10(exp -2) g). Alloys of two different compositions (2% and 5% Cu) were solidified at two different cooling rates. Systematic microscopic and SEM observations produced microstructural and segregation maps for all samples. These maps may be used as benchmark experiments for validation of microstructure evolution and segregation models. As expected, the macro segregation maps are very complex. When segregation was measured along the central axis of the sample, the highest macro segregation for samples solidified at 1g was obtained for the lowest cooling rate. This behavior is attributed to the longer time available for natural convection and shrinkage flow to affect solute redistribution. In samples solidified under low-g, the highest macro-segregation was obtained at the highest cooling rate. In general, low-gravity solidification resulted in less segregation. To explain the experimental findings, an analytical (Flemings-Nereo) and a numerical model were used. For the numerical model, the continuum formulation was employed to describe the macroscopic transports of mass, energy, and momentum, associated with the microscopic transport phenomena, for a two-phase system. The model proposed considers that liquid flow is driven by thermal and solutal buoyancy, and by solidification shrinkage. The Flemings-Nereo model explains well macro segregation in the initial stages of low-gravity segregation. The numerical model can describe the complex macro segregation pattern and the differences between low- and high-gravity solidification.

Multidisciplinary acute care research organization (MACRO): if you build it, they will come.

PubMed

Early, Barbara J; Huang, David T; Callaway, Clifton W; Zenati, Mazen; Angus, Derek C; Gunn, Scott R; Yealy, Donald M; Unikel, Daniel; Billiar, Timothy R; Peitzman, Andrew B; Sperry, Jason L

2013-07-01

Clinical research will increasingly play a core role in the evolution and growth of acute care surgery program development across the country. What constitutes an efficient and effective clinical research infrastructure in the current fiscal and academic environment remains obscure. We sought to characterize the effects of implementation of a multidisciplinary acute care research organization (MACRO) at a busy tertiary referral university setting. In 2008, to minimize redundancy and cost as well as to maximize existing resources promoting acute care research, MACRO was created, unifying clinical research infrastructure among the Departments of Critical Care Medicine, Emergency Medicine, and Surgery. During the periods 2008 to 2012, we performed a retrospective analysis and determined volume of clinical studies, patient enrollment for both observational and interventional trials, and staff growth since MACRO's origination and characterized changes over time. From 2008 to 2011, the volume of patients enrolled in clinical studies, which MACRO facilitates has significantly increased more than 300%. The percentage of interventional/observational trials has remained stable during the same period (50-60%). Staff has increased from 6 coordinators to 10, with an additional 15 research associates allowing 24/7 service. With this significant growth, MACRO has become financially self-sufficient, and additional outside departments now seek MACRO's services. Appropriate organization of acute care clinical research infrastructure minimizes redundancy and can promote sustainable, efficient growth in the current academic environment. Further studies are required to determine if similar models can be successful at other acute care surgery programs.

Response of Florida shelf ecosystems to climate change: from macro to micro scales

USGS Publications Warehouse

Robbins, Lisa; Raabe, Ellen

2010-01-01

U.S. Geological Survey (USGS) research in St. Petersburg, Fla., is focusing attention on marine environments of the Florida shelf at three levels, from regional to estuarine to the individual organism. The USGS is partnering on this project with the Florida Department of Agriculture and Consumer Services (DACS), National Oceanic and Atmospheric Administration (NOAA), and the University of South Florida (USF) in marine studies. The specific goals of these combined efforts are an improved understanding of the effects of ocean acidification on regional carbonate processes, changes in individual estuaries, and organism-level response. This understanding will assist in developing appropriate Federal, State, and local management responses to climate change in coastal areas.

Landslide Hazard Probability Derived from Inherent and Dynamic Determinants

NASA Astrophysics Data System (ADS)

Strauch, Ronda; Istanbulluoglu, Erkan

2016-04-01

Landslide hazard research has typically been conducted independently from hydroclimate research. We unify these two lines of research to provide regional scale landslide hazard information for risk assessments and resource management decision-making. Our approach combines an empirical inherent landslide probability with a numerical dynamic probability, generated by combining routed recharge from the Variable Infiltration Capacity (VIC) macro-scale land surface hydrologic model with a finer resolution probabilistic slope stability model run in a Monte Carlo simulation. Landslide hazard mapping is advanced by adjusting the dynamic model of stability with an empirically-based scalar representing the inherent stability of the landscape, creating a probabilistic quantitative measure of geohazard prediction at a 30-m resolution. Climatology, soil, and topography control the dynamic nature of hillslope stability and the empirical information further improves the discriminating ability of the integrated model. This work will aid resource management decision-making in current and future landscape and climatic conditions. The approach is applied as a case study in North Cascade National Park Complex, a rugged terrain with nearly 2,700 m (9,000 ft) of vertical relief, covering 2757 sq km (1064 sq mi) in northern Washington State, U.S.A.

Model based recovery of histological parameters starting from reflectance spectra of the colon

NASA Astrophysics Data System (ADS)

Hidovic-Rowe, Dzena; Claridge, Ela

2005-06-01

Colon cancer alters the tissue macro-architecture. Changes include increase in blood content and distortion of the collagen matrix, which affect the reflectance spectra of the colon and its colouration. We have developed a physics-based model for predicting colon tissue spectra. The colon structure is represented by three layers: mucosa, submucosa and smooth muscle. Each layer is represented by parameters defining its optical properties: molar concentration and absorption coefficients of haemoglobins, describing absorption of light; size and density of collagen fibres; refractive index of the medium and collagen fibres, describing light scattering; and layer thicknesses. Spectra were calculated using the Monte Carlo method. The output of the model was compared to experimental data comprising 50 spectra acquired in vivo from normal tissue. The extracted histological parameters showed good agreement with known values. An experiment was carried out to study the differences between normal and abnormal tissue. These were characterised by increased blood content and decreased collagen density, which is consistent with known differences between normal and abnormal tissue. This suggests that histological quantities of the colon could be computed from its reflectance spectra. The method is likely to have diagnostic value in the early detection of colon cancer.

Reduction in soil aggregate size distribution due to wind erosion

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2017-04-01

Soil erosion process by wind causes emission of fine soil particles, and thus alters the topsoil's properties, fertility, and erodibility. Topsoil resistance to erosion depends on its physicochemical properties, especially on the soil aggregation. Although the key role of aggregates in soil erodibility, quantitative information on the relations between soil aggregate size distribution (ASD) and erosion is still lucking. This study focuses on ASD analyses before and after soil erosion by wind. Wind tunnel experiments and soil analyses were conducted on semiarid loess topsoils with different initial conditions of aggregation. The results show that in all initial soil conditions saltation of sand particles caused the breakdown of macro-aggregates > 500 µm, resulting in increase of micro-aggregates (63-250 µm). The micro-aggregate production increases with the wind shear velocity (up to 0.61 m s-1) for soils with available macro-aggregates. The findings highlight dynamics in soil aggregation in response to erosion process, and therefore the significance of ASD in quantifying soil degradation and soil loss potential.

Coping with seismic vulnerability: small manufacturing firms in western Athens.

PubMed

Sapountzaki, Kalliopi

2005-06-01

This paper attempts to contribute to international discourse on the responsibility of macro structures (economic and political) and private agencies for the production and distribution of vulnerability. It does so by focusing on an individual economic entity, small manufacturing firms (SMFs), in a specific location, western Athens, Greece. By evaluating the losses that SMFs sustained in the earthquake of 7 September 1999, the paper points to variations in vulnerability levels among such firms and highlights the 'sources' of vulnerability they confront. Furthermore, the SMF recovery cycle is systematically monitored in parallel with relevant public policies and state reactions to private recovery methods. The analysis illustrates processes that externalise recovery costs, alter the relationship between physical and socio-economic vulnerability and shift the vulnerability load from macro structures to individual agencies or vice versa. It is based on two methodological approaches: the division of vulnerability into three constituent components (exposure, resistance and resilience); and the conceptual split between producers and carriers of vulnerability.

Computer modelling of cyclic deformation of high-temperature materials. Technical progress report, 16 November 1992-15 February 1993

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

Duesbery, M.S.

1993-02-26

This program aims at improving current methods of lifetime assessment by building in the characteristics of the micro-mechanisms known to be responsible for damage and failure. The broad approach entails the integration and, where necessary, augmentation of the micro-scale research results currently available in the literature into a macro-scale model with predictive capability. In more detail, the program will develop a set of hierarchically structured models at different length scales, from atomic to macroscopic, at each level taking as parametric input the results of the model at the next smaller scale. In this way the known microscopic properties can bemore » transported by systematic procedures to the unknown macro-scale region. It may not be possible to eliminate empiricism completely, because some of the quantities involved cannot yet be estimated to the required degree of precision. In this case the aim will be at least to eliminate functional empiricism.« less

Macro-grazer herbivory regulates seagrass response to pulse and press nutrient loading.

PubMed

Ravaglioli, Chiara; Capocchi, Antonella; Fontanini, Debora; Mori, Giovanna; Nuccio, Caterina; Bulleri, Fabio

2018-05-01

Coastal ecosystems are exposed to multiple stressors. Predicting their outcomes is complicated by variations in their temporal regimes. Here, by means of a 16-month experiment, we investigated tolerance and resistance traits of Posidonia oceanica to herbivore damage under different regimes of nutrient loading. Chronic and pulse nutrient supply were combined with simulated fish herbivory, treated as a pulse stressor. At ambient nutrient levels, P. oceanica could cope with severe herbivory, likely through an increase in photosynthetic activity. Elevated nutrient levels, regardless of the temporal regime, negatively affected plant growth and increased leaf nutritional quality. This ultimately resulted in a reduction of plant biomass that was particularly severe under chronic fertilization. Our results suggest that both chronic and pulse nutrient loadings increase plant palatability to macro-grazers. Strategies for seagrass management should not be exclusively applied in areas exposed to chronic fertilization since even short-term nutrient pulses could alter seagrass meadows. Copyright © 2018 Elsevier Ltd. All rights reserved.

Photoactive Self-Shaping Hydrogels as Noncontact 3D Macro/Microscopic Photoprinting Platforms.

PubMed

Liao, Yue; An, Ning; Wang, Ning; Zhang, Yinyu; Song, Junfei; Zhou, Jinxiong; Liu, Wenguang

2015-12-01

A photocleavable terpolymer hydrogel cross-linked with o-nitrobenzyl derivative cross-linker is shown to be capable of self-shaping without losing its physical integrity and robustness due to spontaneous asymmetric swelling of network caused by UV-light-induced gradient cleavage of chemical cross-linkages. The continuum model and finite element method are used to elucidate the curling mechanism underlying. Remarkably, based on the self-changing principle, the photosensitive hydrogels can be developed as photoprinting soft and wet platforms onto which specific 3D characters and images are faithfully duplicated in macro/microscale without contact by UV light irradiation under the cover of customized photomasks. Importantly, a quick response (QR) code is accurately printed on the photoactive hydrogel for the first time. Scanning QR code with a smartphone can quickly connect to a web page. This photoactive hydrogel is promising to be a new printing or recording material. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and simulation of Macro-Fiber composite based serrated microflap for wind turbine blade fatigue load reduction

NASA Astrophysics Data System (ADS)

Sun, Xiao; Dai, Qingli; Bilgen, Onur

2018-05-01

A Macro-Fiber Composite (MFC) based active serrated microflap is designed in this research for wind turbine blades. Its fatigue load reduction potential is evaluated in normal operating conditions. The force and displacement output of the MFC-based actuator are simulated using a bimorph beam model. The work done by the aerodynamic, centripetal and gravitational forces acting on the microflap were calculated to determine the required capacity of the MFC-based actuator. MFC-based actuators with a lever mechanical linkage are designed to achieve the required force and displacement to activate the microflap. A feedback control scheme is designed to control the microflap during operation. Through an aerodynamic-aeroelastic time marching simulation with the designed control scheme, the time responses of the wind turbine blades are obtained. The fatigue analysis shows that the serrated microflap can reduce the standard deviation of the blade root flapwise bending moment and the fatigue damage equivalent loads.

2D convolution kernels of ionization chambers used for photon-beam dosimetry in magnetic fields: the advantage of small over large chamber dimensions

NASA Astrophysics Data System (ADS)

Khee Looe, Hui; Delfs, Björn; Poppinga, Daniela; Harder, Dietrich; Poppe, Björn

2018-04-01

This study aims at developing an optimization strategy for photon-beam dosimetry in magnetic fields using ionization chambers. Similar to the familiar case in the absence of a magnetic field, detectors should be selected under the criterion that their measured 2D signal profiles M(x,y) approximate the absorbed dose to water profiles D(x,y) as closely as possible. Since the conversion of D(x,y) into M(x,y) is known as the convolution with the ‘lateral dose response function’ K(x-ξ, y-η) of the detector, the ideal detector would be characterized by a vanishing magnetic field dependence of this convolution kernel (Looe et al 2017b Phys. Med. Biol. 62 5131–48). The idea of the present study is to find out, by Monte Carlo simulation of two commercial ionization chambers of different size, whether the smaller chamber dimensions would be instrumental to approach this aim. As typical examples, the lateral dose response functions in the presence and absence of a magnetic field have been Monte-Carlo modeled for the new commercial ionization chambers PTW 31021 (‘Semiflex 3D’, internal radius 2.4 mm) and PTW 31022 (‘PinPoint 3D’, internal radius 1.45 mm), which are both available with calibration factors. The Monte-Carlo model of the ionization chambers has been adjusted to account for the presence of the non-collecting part of the air volume near the guard ring. The Monte-Carlo results allow a comparison between the widths of the magnetic field dependent photon fluence response function K M(x-ξ, y-η) and of the lateral dose response function K(x-ξ, y-η) of the two chambers with the width of the dose deposition kernel K D(x-ξ, y-η). The simulated dose and chamber signal profiles show that in small photon fields and in the presence of a 1.5 T field the distortion of the chamber signal profile compared with the true dose profile is weakest for the smaller chamber. The dose responses of both chambers at large field size are shown to be altered by not more than 2% in magnetic fields up to 1.5 T for all three investigated chamber orientations.

Simulation of the Mg(Ar) ionization chamber currents by different Monte Carlo codes in benchmark gamma fields

NASA Astrophysics Data System (ADS)

Lin, Yi-Chun; Liu, Yuan-Hao; Nievaart, Sander; Chen, Yen-Fu; Wu, Shu-Wei; Chou, Wen-Tsae; Jiang, Shiang-Huei

2011-10-01

High energy photon (over 10 MeV) and neutron beams adopted in radiobiology and radiotherapy always produce mixed neutron/gamma-ray fields. The Mg(Ar) ionization chambers are commonly applied to determine the gamma-ray dose because of its neutron insensitive characteristic. Nowadays, many perturbation corrections for accurate dose estimation and lots of treatment planning systems are based on Monte Carlo technique. The Monte Carlo codes EGSnrc, FLUKA, GEANT4, MCNP5, and MCNPX were used to evaluate energy dependent response functions of the Exradin M2 Mg(Ar) ionization chamber to a parallel photon beam with mono-energies from 20 keV to 20 MeV. For the sake of validation, measurements were carefully performed in well-defined (a) primary M-100 X-ray calibration field, (b) primary 60Co calibration beam, (c) 6-MV, and (d) 10-MV therapeutic beams in hospital. At energy region below 100 keV, MCNP5 and MCNPX both had lower responses than other codes. For energies above 1 MeV, the MCNP ITS-mode greatly resembled other three codes and the differences were within 5%. Comparing to the measured currents, MCNP5 and MCNPX using ITS-mode had perfect agreement with the 60Co, and 10-MV beams. But at X-ray energy region, the derivations reached 17%. This work shows us a better insight into the performance of different Monte Carlo codes in photon-electron transport calculation. Regarding the application of the mixed field dosimetry like BNCT, MCNP with ITS-mode is recognized as the most suitable tool by this work.

Pattern Recognition Control Design

NASA Technical Reports Server (NTRS)

Gambone, Elisabeth A.

2018-01-01

Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

Method of Fabricating NASA-Standard Macro-Fiber Composite Piezoelectric Actuators

NASA Technical Reports Server (NTRS)

High, James W.; Wilkie, W. Keats

2003-01-01

The NASA Macro-Fiber Composite actuator is a flexible piezoelectric composite device designed for controlling vibrations and shape deformations in high performance aerospace structures. A complete method for fabricating the standard NASA Macro-Fiber Composite actuator is presented in this document. When followed precisely, these procedures will yield devices with electromechanical properties identical to the standard actuator manufactured by NASA Langley Research Center.

Proposal of a method for evaluating tsunami risk using response-surface methodology

NASA Astrophysics Data System (ADS)

Fukutani, Y.

2017-12-01

Information on probabilistic tsunami inundation hazards is needed to define and evaluate tsunami risk. Several methods for calculating these hazards have been proposed (e.g. Løvholt et al. (2012), Thio (2012), Fukutani et al. (2014), Goda et al. (2015)). However, these methods are inefficient, and their calculation cost is high, since they require multiple tsunami numerical simulations, therefore lacking versatility. In this study, we proposed a simpler method for tsunami risk evaluation using response-surface methodology. Kotani et al. (2016) proposed an evaluation method for the probabilistic distribution of tsunami wave-height using a response-surface methodology. We expanded their study and developed a probabilistic distribution of tsunami inundation depth. We set the depth (x1) and the slip (x2) of an earthquake fault as explanatory variables and tsunami inundation depth (y) as an object variable. Subsequently, tsunami risk could be evaluated by conducting a Monte Carlo simulation, assuming that the generation probability of an earthquake follows a Poisson distribution, the probability distribution of tsunami inundation depth follows the distribution derived from a response-surface, and the damage probability of a target follows a log normal distribution. We applied the proposed method to a wood building located on the coast of Tokyo Bay. We implemented a regression analysis based on the results of 25 tsunami numerical calculations and developed a response-surface, which was defined as y=ax1+bx2+c (a:0.2615, b:3.1763, c=-1.1802). We assumed proper probabilistic distribution for earthquake generation, inundation height, and vulnerability. Based on these probabilistic distributions, we conducted Monte Carlo simulations of 1,000,000 years. We clarified that the expected damage probability of the studied wood building is 22.5%, assuming that an earthquake occurs. The proposed method is therefore a useful and simple way to evaluate tsunami risk using a response-surface and Monte Carlo simulation without conducting multiple tsunami numerical simulations.

Wet-based glaciation in Phlegra Montes, Mars.

NASA Astrophysics Data System (ADS)

Gallagher, Colman; Balme, Matt

2016-04-01

Eskers are sinuous landforms composed of sediments deposited from meltwaters in ice-contact glacial conduits. This presentation describes the first definitive identification of eskers on Mars still physically linked with their parent system (1), a Late Amazonian-age glacier (~150 Ma) in Phlegra Montes. Previously described Amazonian-age glaciers on Mars are generally considered to have been dry based, having moved by creep in the absence of subglacial water required for sliding, but our observations indicate significant sub-glacial meltwater routing. The confinement of the Phlegra Montes glacial system to a regionally extensive graben is evidence that the esker formed due to sub-glacial melting in response to an elevated, but spatially restricted, geothermal heat flux rather than climate-induced warming. Now, however, new observations reveal the presence of many assemblages of glacial abrasion forms and associated channels that could be evidence of more widespread wet-based glaciation in Phlegra Montes, including the collapse of several distinct ice domes. This landform assemblage has not been described in other glaciated, mid-latitude regions of the martian northern hemisphere. Moreover, Phlegra Montes are flanked by lowlands displaying evidence of extensive volcanism, including contact between plains lava and piedmont glacial ice. These observations provide a rationale for investigating non-climatic forcing of glacial melting and associated landscape development on Mars, and can build on insights from Earth into the importance of geothermally-induced destabilisation of glaciers as a key amplifier of climate change. (1) Gallagher, C. and Balme, M. (2015). Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars, Earth and Planetary Science Letters, 431, 96-109.

Macro-Climatic Distribution Limits Show Both Niche Expansion and Niche Specialization among C4 Panicoids.

PubMed

Aagesen, Lone; Biganzoli, Fernando; Bena, Julia; Godoy-Bürki, Ana C; Reinheimer, Renata; Zuloaga, Fernando O

2016-01-01

Grasses are ancestrally tropical understory species whose current dominance in warm open habitats is linked to the evolution of C4 photosynthesis. C4 grasses maintain high rates of photosynthesis in warm and water stressed environments, and the syndrome is considered to induce niche shifts into these habitats while adaptation to cold ones may be compromised. Global biogeographic analyses of C4 grasses have, however, concentrated on diversity patterns, while paying little attention to distributional limits. Using phylogenetic contrast analyses, we compared macro-climatic distribution limits among ~1300 grasses from the subfamily Panicoideae, which includes 4/5 of the known photosynthetic transitions in grasses. We explored whether evolution of C4 photosynthesis correlates with niche expansions, niche changes, or stasis at subfamily level and within the two tribes Paniceae and Paspaleae. We compared the climatic extremes of growing season temperatures, aridity, and mean temperatures of the coldest months. We found support for all the known biogeographic distribution patterns of C4 species, these patterns were, however, formed both by niche expansion and niche changes. The only ubiquitous response to a change in the photosynthetic pathway within Panicoideae was a niche expansion of the C4 species into regions with higher growing season temperatures, but without a withdrawal from the inherited climate niche. Other patterns varied among the tribes, as macro-climatic niche evolution in the American tribe Paspaleae differed from the pattern supported in the globally distributed tribe Paniceae and at family level.

Studying policy implementation using a macro, meso and micro frame analysis: the case of the Collaboration for Leadership in Applied Health Research & Care (CLAHRC) programme nationally and in North West London.

PubMed

Caldwell, Sarah E M; Mays, Nicholas

2012-10-15

The publication of Best research for best health in 2006 and the "ring-fencing" of health research funding in England marked the start of a period of change for health research governance and the structure of research funding in England. One response to bridging the 'second translational gap' between research knowledge and clinical practice was the establishment of nine Collaborations for Leadership in Applied Health Research and Care (CLAHRCs). The goal of this paper is to assess how national-level understanding of the aims and objectives of the CLAHRCs translated into local implementation and practice in North West London. This study uses a variation of Goffman's frame analysis to trace the development of the initial national CLAHRC policy to its implementation at three levels. Data collection and analysis were qualitative through interviews, document analysis and embedded research. Analysis at the macro (national policy), meso (national programme) and micro (North West London) levels shows a significant common understanding of the aims and objectives of the policy and programme. Local level implementation in North West London was also consistent with these. The macro-meso-micro frame analysis is a useful way of studying the transition of a policy from high-level idea to programme in action. It could be used to identify differences at a local (micro) level in the implementation of multi-site programmes that would help understand differences in programme effectiveness.

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

Lessard, Francois; Archambault, Louis; Plamondon, Mathieu

Purpose: Photon dosimetry in the kilovolt (kV) energy range represents a major challenge for diagnostic and interventional radiology and superficial therapy. Plastic scintillation detectors (PSDs) are potentially good candidates for this task. This study proposes a simple way to obtain accurate correction factors to compensate for the response of PSDs to photon energies between 80 and 150 kVp. The performance of PSDs is also investigated to determine their potential usefulness in the diagnostic energy range. Methods: A 1-mm-diameter, 10-mm-long PSD was irradiated by a Therapax SXT 150 unit using five different beam qualities made of tube potentials ranging from 80more » to 150 kVp and filtration thickness ranging from 0.8 to 0.2 mmAl + 1.0 mmCu. The light emitted by the detector was collected using an 8-m-long optical fiber and a polychromatic photodiode, which converted the scintillation photons to an electrical current. The PSD response was compared with the reference free air dose rate measured with a calibrated Farmer NE2571 ionization chamber. PSD measurements were corrected using spectra-weighted corrections, accounting for mass energy-absorption coefficient differences between the sensitive volumes of the ionization chamber and the PSD, as suggested by large cavity theory (LCT). Beam spectra were obtained from x-ray simulation software and validated experimentally using a CdTe spectrometer. Correction factors were also obtained using Monte Carlo (MC) simulations. Percent depth dose (PDD) measurements were compensated for beam hardening using the LCT correction method. These PDD measurements were compared with uncorrected PSD data, PDD measurements obtained using Gafchromic films, Monte Carlo simulations, and previous data. Results: For each beam quality used, the authors observed an increase of the energy response with effective energy when no correction was applied to the PSD response. Using the LCT correction, the PSD response was almost energy independent, with a residual 2.1% coefficient of variation (COV) over the 80-150-kVp energy range. Monte Carlo corrections reduced the COV to 1.4% over this energy range. All PDD measurements were in good agreement with one another except for the uncorrected PSD data, in which an over-response was observed with depth (13% at 10 cm with a 100 kVp beam), showing that beam hardening had a non-negligible effect on the PSD response. A correction based on LCT compensated very well for this effect, reducing the over-response to 3%.Conclusion: In the diagnostic energy range, PSDs show high-energy dependence, which can be corrected using spectra-weighted mass energy-absorption coefficients, showing no considerable sign of quenching between these energies. Correction factors obtained by Monte Carlo simulations confirm that the approximations made by LCT corrections are valid. Thus, PSDs could be useful for real-time dosimetry in radiology applications.« less

Limited protection of macro-aggregate-occluded organic carbon in Siberian steppe soils

NASA Astrophysics Data System (ADS)

Bischoff, Norbert; Mikutta, Robert; Shibistova, Olga; Puzanov, Alexander; Silanteva, Marina; Grebennikova, Anna; Fuß, Roland; Guggenberger, Georg

2017-05-01

Macro-aggregates especially in agricultural steppe soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in steppes focused on North American prairie soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian steppe soils, we determined OC mineralization rates of intact (250-2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda steppe. Additionally, we incubated bulk soil (< 2000 µm) to determine the effect of LUC and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential-decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land use intensity and time since LUC increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land use regimes. Macro-aggregate-protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to a maximum of 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by land use intensity and time since LUC. However, at one chronosequence mean residence times of the fast and slow OC pool tended to decrease with increasing time since establishment of arable use. We conclude that the tillage-induced breakdown of macro-aggregates has not reduced the OC contents in the soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.

Signal pulse emulation for scintillation detectors using Geant4 Monte Carlo with light tracking simulation.

PubMed

Ogawara, R; Ishikawa, M

2016-07-01

The anode pulse of a photomultiplier tube (PMT) coupled with a scintillator is used for pulse shape discrimination (PSD) analysis. We have developed a novel emulation technique for the PMT anode pulse based on optical photon transport and a PMT response function. The photon transport was calculated using Geant4 Monte Carlo code and the response function with a BC408 organic scintillator. The obtained percentage RMS value of the difference between the measured and simulated pulse with suitable scintillation properties using GSO:Ce (0.4, 1.0, 1.5 mol%), LaBr3:Ce and BGO scintillators were 2.41%, 2.58%, 2.16%, 2.01%, and 3.32%, respectively. The proposed technique demonstrates high reproducibility of the measured pulse and can be applied to simulation studies of various radiation measurements.

Monte Carlo investigation of transient acoustic fields in partially or completely bounded medium. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Thanedar, B. D.

1972-01-01

A simple repetitive calculation was used to investigate what happens to the field in terms of the signal paths of disturbances originating from the energy source. The computation allowed the field to be reconstructed as a function of space and time on a statistical basis. The suggested Monte Carlo method is in response to the need for a numerical method to supplement analytical methods of solution which are only valid when the boundaries have simple shapes, rather than for a medium that is bounded. For the analysis, a suitable model was created from which was developed an algorithm for the estimation of acoustic pressure variations in the region under investigation. The validity of the technique was demonstrated by analysis of simple physical models with the aid of a digital computer. The Monte Carlo method is applicable to a medium which is homogeneous and is enclosed by either rectangular or curved boundaries.

Finite Macro-Element Mesh Deformation in a Structured Multi-Block Navier-Stokes Code

NASA Technical Reports Server (NTRS)

Bartels, Robert E.

2005-01-01

A mesh deformation scheme is developed for a structured multi-block Navier-Stokes code consisting of two steps. The first step is a finite element solution of either user defined or automatically generated macro-elements. Macro-elements are hexagonal finite elements created from a subset of points from the full mesh. When assembled, the finite element system spans the complete flow domain. Macro-element moduli vary according to the distance to the nearest surface, resulting in extremely stiff elements near a moving surface and very pliable elements away from boundaries. Solution of the finite element system for the imposed boundary deflections generally produces smoothly varying nodal deflections. The manner in which distance to the nearest surface has been found to critically influence the quality of the element deformation. The second step is a transfinite interpolation which distributes the macro-element nodal deflections to the remaining fluid mesh points. The scheme is demonstrated for several two-dimensional applications.

Time to death and the forecasting of macro-level health care expenditures: some further considerations.

PubMed

van Baal, Pieter H; Wong, Albert

2012-12-01

Although the effect of time to death (TTD) on health care expenditures (HCE) has been investigated using individual level data, the most profound implications of TTD have been for the forecasting of macro-level HCE. Here we estimate the TTD model using macro-level data from the Netherlands consisting of mortality rates and age- and gender-specific per capita health expenditures for the years 1981-2007. Forecasts for the years 2008-2020 of this macro-level TTD model were compared to forecasts that excluded TTD. Results revealed that the effect of TTD on HCE in our macro model was similar to those found in micro-econometric studies. As the inclusion of TTD pushed growth rate estimates from unidentified causes upwards, however, the two models' forecasts of HCE for the 2008-2020 were similar. We argue that including TTD, if modeled correctly, does not lower forecasts of HCE. Copyright © 2012 Elsevier B.V. All rights reserved.

Are biotic indices sensitive to river toxicants? A comparison of metrics based on diatoms and macro-invertebrates.

PubMed

Blanco, S; Bécares, E

2010-03-01

Biotic indices based on macro-invertebrates and diatoms are frequently used to diagnose ecological quality in watercourses, but few published works have assessed their effectiveness as biomonitors of the concentration of micropollutants. A biological survey performed at 188 sites in the basin of the River Duero in north-western Spain. Nineteen diatom and six macro-invertebrate indices were calculated and compared with the concentrations of 37 different toxicants by means of a correlation analysis. Several chemical variables analysed correlated significantly with at least one biotic index. Sládecek's diatom index and the number of macro-invertebrate families exhibited particularly high correlation coefficients. Methods based on macro-invertebrates performed better in detecting biocides, while diatom indices showed stronger correlations with potentially toxic elements such as heavy metals. All biotic indices, and particularly diatom indices, were especially sensitive to the concentration of fats and oils and trichloroethene. Copyright 2010 Elsevier Ltd. All rights reserved.

Macro-Level Approaches to HIV Prevention Among Ethnic Minority Youth

PubMed Central

Prado, Guillermo; Lightfoot, Marguerita; Brown, C. Hendricks

2013-01-01

The HIV epidemic continues to disproportionately affect ethnic minority youth. These disconcerting health disparities indicate that although existing HIV preventive strategies for ethnic minority youth have been efficacious, they have not significantly reduced the impact of the epidemic in this population. Macro-level interventions, such as structural or policy interventions, have the potential to impact the HIV epidemic at a population level, and thus reduce the HIV health disparities that exist among ethnic minority youth and other segments of the U.S. population. This article calls for a paradigm shift to develop, evaluate, and disseminate interventions that target upstream/macro-level factors or that, at a minimum, integrate both a macro and individual level perspective. The article also discusses the challenges in developing and evaluating such interventions. Psychologists and other behavioral scientists can play a critical role in reducing the impact of HIV on ethnic minority youth by integrating macro-level approaches to future HIV prevention strategies. PMID:23688095

Intelligent Learning System using cognitive science theory and artificial intelligence methods

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

Cristensen, D.L.

1986-01-01

This dissertation is a presentation of a theoretical model of an intelligent Learning System (ILS). The approach view intelligent computer-based instruction on a curricular-level and educational-theory base, instead of the conventional instructional-only level. The ILS is divided into two components: (1) macro-level, curricular; and (2) micro-level (MAIS), instructional. The primary purpose of the ILS macro level is to establish the initial conditions of learning by considering individual difference variables within specification of the curriculum content domain. Second, the ILS macro-level will iteratively update the conditions of learning as the individual student progresses through the given curriculum. The term dynamic ismore » used to describe the expert tutor that establishes and monitors the conditions of instruction between the ILS macro level and the micro level. As the student progresses through the instruction, appropriate information is sent back continuously to the macro level to constantly improve decision making for succeeding conditions of instruction.« less

Sustaining anti-littering behavior within coastal and marine environments: Through the macro-micro level lenses.

PubMed

Beeharry, Yashna Devi; Bekaroo, Girish; Bokhoree, Chandradeo; Phillips, Michael Robert; Jory, Neelakshi

2017-06-30

Being regarded as a problem of global dimensions, marine litter has been a growing concern that affects human beings, wildlife and the economic health of coastal communities to varying degrees. Due to its involvement with human behavior, marine littering has been regarded as a cultural matter encompassing macro and micro level aspects. At the micro or individual level, behavior and behavioral motivation of an individual are driven by perception of that person while at the macro or societal level, aspects including policies and legislations influence behavior. This paper investigates marine littering through the macro-micro level lenses in order to analyze and recommend how anti-littering behavior can be improved and sustained. Using Coleman's model of micro-macro relations, research questions are formulated and investigated through a social survey. Results showed important differences in perceptions among participating groups and to address key issues, potential actions are proposed along with a framework to sustain anti-littering behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation and comparison of absorbed dose for electron beams by LiF and diamond dosimeters

NASA Astrophysics Data System (ADS)

Mosia, G. J.; Chamberlain, A. C.

2007-09-01

The absorbed dose response of LiF and diamond thermoluminescent dosimeters (TLDs), calibrated in 60Co γ-rays, has been determined using the MCNP4B Monte Carlo code system in mono-energetic megavoltage electron beams from 5 to 20 MeV. Evaluation of the dose responses was done against the dose responses of published works by other investigators. Dose responses of both dosimeters were compared to establish if any relation exists between them. The dosimeters were irradiated in a water phantom with the centre of their top surfaces (0.32×0.32 cm 2), placed at dmax perpendicular to the radiation beam on the central axis. For LiF TLD, dose responses ranged from 0.945±0.017 to 0.997±0.011. For the diamond TLD, the dose response ranged from 0.940±0.017 to 1.018±0.011. To correct for dose responses by both dosimeters, energy correction factors were generated from dose response results of both TLDs. For LiF TLD, these correction factors ranged from 1.003 up to 1.058 and for diamond TLD the factors ranged from 0.982 up to 1.064. The results show that diamond TLDs can be used in the place of the well-established LiF TLDs and that Monte Carlo code systems can be used in dose determinations for radiotherapy treatment planning.

The Development of Louis MACRO (Mother and Child Risk Observation) Forms: Assessing Parent-Infant-Child Risk in the Presence of Maternal Mental Illness.

ERIC Educational Resources Information Center

Louis, Andrea; And Others

1997-01-01

An Australian study of 110 mother-infant dyads and 85 mother-toddler dyads in which the mothers were mentally ill evaluated the effectiveness of the Mother and Child Risk Observation (MACRO). Results found that MACRO offers a convenient framework for assessing risk and interpreting the impact of maternal mental illness upon children. (Author/CR)

[A global view of population health in Colombia: role of social macro-determinants].

PubMed

Idrovo, Alvaro J; Ruiz-Rodríguez, Myriam

2007-09-01

The social environment is an important determinant of population and individual health. However, its impact is often not considered in national health policies and generally its attributes are considered as constants. For this reason, contemporary health policies place greater emphasis on individual risk factors. Colombias position in the world ranking is described with respect to several social macro-determinants of health, previously characterized as components of class/welfare regime model. The exploratory study included all countries with comparable data including the following: (1) economic development [gross domestic product per capita adjusted for purchasing power parity], (2) income inequality [Gini coefficient], (3) social capital corruption perceptions index and generalized trust, and (4) political regime index of freedom. First, correlations between these macro-determinants were estimated, and second, the relationship between them and life expectancy at birth was explored. Finally, the position of Colombia in global context was determined. Important correlations occurred among the macro-determinants. Colombia tended to have intermediate to low positions in the global context in all macro-determinants, with the exception of gross domestic product per capita adjusted for purchasing power parity. The macro-determinant of population health with the highest potential of effecting improvement in health conditions is to modify income inequality.

Macro- and micro-level predictors of age categorization: results from the European Social Survey.

PubMed

Ayalon, Liat; Doron, Israel; Bodner, Ehud; Inbar, Noit

2014-03-01

This study evaluated macro- and micro-level variables associated with individuals' perception of the ending of youth, the beginning of old age, and the length of the middle age period. The European Social Survey is a biennial multi-country, cross-sectional survey. Our analysis is based on the fourth wave, which included a rotating module on ageism. The source sample consisted of 28 countries and a total of 54,988 respondents. Whereas macro-level variability accounted for 14 % of the variance associated with the perception of the ending of youth, only 5.7 % of the variance associated with the perception of the beginning of old age was accounted for by macro-level variability. Almost 10 % of the variance associated with the perception of the middle age period was associated with macro-level variability. Different patterns of macro- and micro-level correlates emerged for the ending of youth, beginning of old age, and the period of middle age. Overall, results demonstrate that individual differences in the perception of the ending of youth, the beginning of old age, and the length of the middle age period are more pronounced than contextual differences. Results also suggest that individuals' mental maps regarding the timing of these events are not necessarily concordant.

Managing protected health information in distributed research network environments: automated review to facilitate collaboration

PubMed Central

2013-01-01

Background Multi-site health sciences research is becoming more common, as it enables investigation of rare outcomes and diseases and new healthcare innovations. Multi-site research usually involves the transfer of large amounts of research data between collaborators, which increases the potential for accidental disclosures of protected health information (PHI). Standard protocols for preventing release of PHI are extremely vulnerable to human error, particularly when the shared data sets are large. Methods To address this problem, we developed an automated program (SAS macro) to identify possible PHI in research data before it is transferred between research sites. The macro reviews all data in a designated directory to identify suspicious variable names and data patterns. The macro looks for variables that may contain personal identifiers such as medical record numbers and social security numbers. In addition, the macro identifies dates and numbers that may identify people who belong to small groups, who may be identifiable even in the absences of traditional identifiers. Results Evaluation of the macro on 100 sample research data sets indicated a recall of 0.98 and precision of 0.81. Conclusions When implemented consistently, the macro has the potential to streamline the PHI review process and significantly reduce accidental PHI disclosures. PMID:23521861

Efficient radiologic reading environment by using an open-source macro program as connection software.

PubMed

Lee, Young Han

2012-01-01

The objectives are (1) to introduce an easy open-source macro program as connection software and (2) to illustrate the practical usages in radiologic reading environment by simulating the radiologic reading process. The simulation is a set of radiologic reading process to do a practical task in the radiologic reading room. The principal processes are: (1) to view radiologic images on the Picture Archiving and Communicating System (PACS), (2) to connect the HIS/EMR (Hospital Information System/Electronic Medical Record) system, (3) to make an automatic radiologic reporting system, and (4) to record and recall information of interesting cases. This simulation environment was designed by using open-source macro program as connection software. The simulation performed well on the Window-based PACS workstation. Radiologists practiced the steps of the simulation comfortably by utilizing the macro-powered radiologic environment. This macro program could automate several manual cumbersome steps in the radiologic reading process. This program successfully acts as connection software for the PACS software, EMR/HIS, spreadsheet, and other various input devices in the radiologic reading environment. A user-friendly efficient radiologic reading environment could be established by utilizing open-source macro program as connection software. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

GPS Radiation Measurements: Instrument Modeling and Simulation (Project w14_gpsradiation)

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

Sullivan, John P.

The following topics are covered: electron response simulations and typical calculated response. Monte Carlo calculations of the response of future charged particle instruments (dosimeters) intended to measure the flux of charged particles in space were performed. The electron channels are called E1- E11 – each of which is intended to detect a different range of electron energies. These instruments are on current and future GPS satellites.

Charge-transfer excited states: Seeking a balanced and efficient wave function ansatz in variational Monte Carlo

DOE PAGES

Blunt, Nick S.; Neuscamman, Eric

2017-11-16

We present a simple and efficient wave function ansatz for the treatment of excited charge-transfer states in real-space quantum Monte Carlo methods. Using the recently-introduced variation-after-response method, this ansatz allows a crucial orbital optimization step to be performed beyond a configuration interaction singles expansion, while only requiring calculation of two Slater determinant objects. As a result, we demonstrate this ansatz for the illustrative example of the stretched LiF molecule, for a range of excited states of formaldehyde, and finally for the more challenging ethylene-tetrafluoroethylene molecule.

Plant litter functional diversity effects on litter mass loss depend on the macro-detritivore community.

PubMed

Patoine, Guillaume; Thakur, Madhav P; Friese, Julia; Nock, Charles; Hönig, Lydia; Haase, Josephine; Scherer-Lorenzen, Michael; Eisenhauer, Nico

2017-11-01

A better understanding of the mechanisms driving litter diversity effects on decomposition is needed to predict how biodiversity losses affect this crucial ecosystem process. In a microcosm study, we investigated the effects of litter functional diversity and two major groups of soil macro-detritivores on the mass loss of tree leaf litter mixtures. Furthermore, we tested the effects of litter trait community means and dissimilarity on litter mass loss for seven traits relevant to decomposition. We expected macro-detritivore effects on litter mass loss to be most pronounced in litter mixtures of high functional diversity. We used 24 leaf mixtures differing in functional diversity, which were composed of litter from four species from a pool of 16 common European tree species. Earthworms, isopods, or a combination of both were added to each litter combination for two months. Litter mass loss was significantly higher in the presence of earthworms than in that of isopods, whereas no synergistic effects of macro-detritivore mixtures were found. The effect of functional diversity of the litter material was highest in the presence of both macro-detritivore groups, supporting the notion that litter diversity effects are most pronounced in the presence of different detritivore species. Species-specific litter mass loss was explained by nutrient content, secondary compound concentration, and structural components. Moreover, dissimilarity in N concentrations increased litter mass loss, probably because detritivores having access to nutritionally diverse food sources. Furthermore, strong competition between the two macro-detritivores for soil surface litter resulted in a decrease of survival of both macro-detritivores. These results show that the effects of litter functional diversity on decomposition are contingent upon the macro-detritivore community and composition. We conclude that the temporal dynamics of litter trait diversity effects and their interaction with detritivore diversity are key to advancing our understanding of litter mass loss in nature.

Plant litter functional diversity effects on litter mass loss depend on the macro-detritivore community

PubMed Central

Patoine, Guillaume; Thakur, Madhav P.; Friese, Julia; Nock, Charles; Hönig, Lydia; Haase, Josephine; Scherer-Lorenzen, Michael; Eisenhauer, Nico

2017-01-01

A better understanding of the mechanisms driving litter diversity effects on decomposition is needed to predict how biodiversity losses affect this crucial ecosystem process. In a microcosm study, we investigated the effects of litter functional diversity and two major groups of soil macro-detritivores on the mass loss of tree leaf litter mixtures. Furthermore, we tested the effects of litter trait community means and dissimilarity on litter mass loss for seven traits relevant to decomposition. We expected macro-detritivore effects on litter mass loss to be most pronounced in litter mixtures of high functional diversity. We used 24 leaf mixtures differing in functional diversity, which were composed of litter from four species from a pool of 16 common European tree species. Earthworms, isopods, or a combination of both were added to each litter combination for two months. Litter mass loss was significantly higher in the presence of earthworms than in that of isopods, whereas no synergistic effects of macro-detritivore mixtures were found. The effect of functional diversity of the litter material was highest in the presence of both macro-detritivore groups, supporting the notion that litter diversity effects are most pronounced in the presence of different detritivore species. Species-specific litter mass loss was explained by nutrient content, secondary compound concentration, and structural components. Moreover, dissimilarity in N concentrations increased litter mass loss, probably because detritivores having access to nutritionally diverse food sources. Furthermore, strong competition between the two macro-detritivores for soil surface litter resulted in a decrease of survival of both macro-detritivores. These results show that the effects of litter functional diversity on decomposition are contingent upon the macro-detritivore community and composition. We conclude that the temporal dynamics of litter trait diversity effects and their interaction with detritivore diversity are key to advancing our understanding of litter mass loss in nature. PMID:29180828

A structuration framework for bridging the macro-micro divide in health-care governance.

PubMed

Bodolica, Virginia; Spraggon, Martin; Tofan, Gabriela

2016-08-01

Extant studies demonstrate that macro (hierarchical) and micro (relational) governance initiatives in health-care settings continue to be developed in isolation rather than interactively. Government-driven hierarchical governance endeavours that guide health-care reforms and medical practice are disconnected from micro-level physician-patient interactions being unable to account for patient preferences in the macro-level policymaking. We undertake a review of the recent literature to couch our argument for a unified governance framework for bridging the macro-micro divide in medical contexts. Adopting an interdisciplinary approach to health-care delivery, we maintain that the (strong) structuration theory provides a fruitful opportunity for narrowing the gap between hierarchical and relational governance. Emphasizing the coexistence of institutional structures and human agency, the (strong) structuration theory elucidates how macro and micro governance devices shape each other's structure via mutually reinforcing cycles of influence. Micro-level encounters between patients and physicians give rise to social structures that constitute the constraining and enabling forces through which macro-level health-care infrastructures are altered and reproduced over time. Permitting to illustrate how patients' agency can effectively emerge from complex networks of clinical trajectories, the advanced structuration framework for macro-micro governance integration avoids the extremes of paternalism and autonomy through a balanced consideration of professional judgement and patient preferences. The macro-micro integration of governance efforts is a critical issue in both high-income states, where medical institutions attempt to deploy substantial realignment efforts, and developing nations, which are lagging behind due to leadership weaknesses and lower levels of governmental investment. A key priority for regulators is the identification of relevant systems to support this holistic governance by providing clinicians with needed resources for focusing on patient advocacy and installing enabling mechanisms for incorporating patients' inputs in health-care reforms and policymaking. © 2015 John Wiley & Sons Ltd.

The Consequences of Ignoring Item Parameter Drift in Longitudinal Item Response Models

ERIC Educational Resources Information Center

Lee, Wooyeol; Cho, Sun-Joo

2017-01-01

Utilizing a longitudinal item response model, this study investigated the effect of item parameter drift (IPD) on item parameters and person scores via a Monte Carlo study. Item parameter recovery was investigated for various IPD patterns in terms of bias and root mean-square error (RMSE), and percentage of time the 95% confidence interval covered…

A Mixture Rasch Model with a Covariate: A Simulation Study via Bayesian Markov Chain Monte Carlo Estimation

ERIC Educational Resources Information Center

Dai, Yunyun

2013-01-01

Mixtures of item response theory (IRT) models have been proposed as a technique to explore response patterns in test data related to cognitive strategies, instructional sensitivity, and differential item functioning (DIF). Estimation proves challenging due to difficulties in identification and questions of effect size needed to recover underlying…

Direct Estimation of Correlation as a Measure of Association Strength Using Multidimensional Item Response Models

ERIC Educational Resources Information Center

Wang, Wen-Chung

2004-01-01

The Pearson correlation is used to depict effect sizes in the context of item response theory. Amultidimensional Rasch model is used to directly estimate the correlation between latent traits. Monte Carlo simulations were conducted to investigate whether the population correlation could be accurately estimated and whether the bootstrap method…

Influence of the individual or combined application of biochar and slurry on soil macro-aggregate formation under varying moisture conditions

NASA Astrophysics Data System (ADS)

Kaiser, Michael; Grunwald, Dennis; Koch, Heinz-Josef; Rauber, Rolf; Ludwig, Bernard

2017-04-01

The formation of aggregates is of large importance for the structure and the storage of organic matter (OM) in soil. Although positive effects of organic soil additives on the formation of macro-aggregates (> 250 µm) have been reported, the influence of biochar especially applied in combination with other organic amendments remains unclear. Furthermore, studies on the effect of varying soil moisture conditions in form of drying-rewetting cycles on soil aggregate dynamics in the presence of biochar are almost missing. The objectives of this study were to analyze the effects of biochar and slurry applied to the soil individually or in combination on the formation of macro-aggregates under constant and under varying moisture conditions. We sampled four silty loam soils, carefully crushed the soil macro-aggregates, and incubated the soil at 15 °C for 60 days with the following additions: (i) none (control), (ii) biochar (12 % of dry soil mass), (iii) slurry (150 kg N ha-1), (iv) biochar (6 %) + slurry (75 kg N ha-1), (v) biochar (12 %) + slurry (75 kg N ha-1), (vi) biochar (6 %) + slurry (150 kg N ha-1) and (vii) biochar (12 %) + slurry (150 kg N ha-1). The samples were further subdivided into two groups that were incubated under conditions of constant soil moisture and of three drying-rewetting cycles. The CO2 fluxes were continuously measured during the incubation period and the samples were analyzed for microbial biomass C, macro-aggregate yields and macro-aggregate-associated C after finishing the experiment. We found the application of biochar to result in lower macro-aggregate yields with or without slurry compared to the control or the individual slurry application. In contrast, similar or higher C contents in the macro-aggregate fraction of the biochar treatments as compared to the control or slurry treatments were found indicating an occlusion of biochar in macro-aggregates. Due to the sorption characteristics of biochar, we assume the aggregate formation to be partially abiotic with direct interactions between biochar, (adsorbed) slurry, and the mineral phase of the soil. Therefore, in the presence of slurry, a prolonged period of microbial processing does not seem to be necessary to render the biochar suitable to form aggregates. Drying and rewetting of the samples resulted in significantly lower aggregate yields especially for the biochar/slurry mixtures. The drying of slurry as thought to be the most important macro-aggregate binding agent in these treatments might irreversibly disrupt large amounts of the macro-aggregates formed. Additionally, the general lower microbial biomass C and CO2 emissions for the samples experiencing drying-rewetting cycles compared to the constantly moist soils point toward less microbial activity under varying moisture conditions. This might have led to less microbial derived aggregate binding agents contributing to the lower aggregate yields found for the samples from the drying-rewetting treatments. Beside the amount and type of binding agents derived from organic soil additives, the formation and stability of soil macro-aggregate seem also to be controlled by climatically controlled soil moisture conditions.

Comparison of Measured Dark Current Distributions with Calculated Damage Energy Distributions in HgCdTe

NASA Technical Reports Server (NTRS)

Marshall, C. J.; Marshall, P. W.; Howe, C. L.; Reed, R. A.; Weller, R. A.; Mendenhall, M.; Waczynski, A.; Ladbury, R.; Jordan, T. M.

2007-01-01

This paper presents a combined Monte Carlo and analytic approach to the calculation of the pixel-to-pixel distribution of proton-induced damage in a HgCdTe sensor array and compares the results to measured dark current distributions after damage by 63 MeV protons. The moments of the Coulombic, nuclear elastic and nuclear inelastic damage distributions were extracted from Monte Carlo simulations and combined to form a damage distribution using the analytic techniques first described in [1]. The calculations show that the high energy recoils from the nuclear inelastic reactions (calculated using the Monte Carlo code MCNPX [2]) produce a pronounced skewing of the damage energy distribution. While the nuclear elastic component (also calculated using the MCNPX) contributes only a small fraction of the total nonionizing damage energy, its inclusion in the shape of the damage across the array is significant. The Coulombic contribution was calculated using MRED [3-5], a Geant4 [4,6] application. The comparison with the dark current distribution strongly suggests that mechanisms which are not linearly correlated with nonionizing damage produced according to collision kinematics are responsible for the observed dark current increases. This has important implications for the process of predicting the on-orbit dark current response of the HgCdTe sensor array.

Individualized Human CAD Models: Anthropmetric Morphing and Body Tissue Layering

DTIC Science & Technology

2014-07-31

Part Flow Chart of the Interaction among VBA Macros, Excel® Spreadsheet, and SolidWorks Front View of the Male and Female Soldier CAD Model...yellow highlighting. The spreadsheet is linked to the CAD model by macros created with the Visual Basic for Application ( VBA ) editor in Microsoft Excel...basically three working parts to the anthropometric morphing that are all interconnected ( VBA macros, Excel spreadsheet, and SolidWorks). The flow

Learning to Solve Problems by Searching for Macro-Operators

DTIC Science & Technology

1983-07-01

executing generalized robot plans. Aritificial Intelligence 3:25 1-288, 1972. [Frey 821 Frey, Alexander Ii. Jr., and David Singmaster. Handbook of Cubik...and that searching for macros may be a useful general learning paradigm. 1.1. Introduction One view of die die field of artificial intelligence is that... intelligence literature [Schofield 67, Gaschnig 79, Ericsson 761 and provides one of the simplest examples of the operation of the Macro Problem Solver. It

Macro-level social forces and micro-level consequences: poverty, alternate occupations, and drug dealing.

PubMed

Dunlap, Eloise; Johnson, Bruce D; Kotarba, Joseph A; Fackler, Jennifer L

2010-01-01

This article is an empirical examination of the ways in which macro-level social forces have had micro-level consequences in the New Orleans drug market. The article illustrates a clear connection between poverty and entrance into the drug market, as mitigated by race, lack of societal opportunity, lack of social capital, distressed families, and closed neighborhoods. Specifically, the research illustrates the mechanisms by which macro-level social forces intersect to legitimize drug dealing as a viable alternative method of acquiring money and social capital. These intersecting macro-level social forces, such as poverty, race, family structure, and neighborhood characteristics, ultimately constrain the life chances of those living in the inner city irrespective of personal traits, individual motivations, or private achievements.

PETRO.CALC.PLOT, Microsoft Excel macros to aid petrologic interpretation

USGS Publications Warehouse

Sidder, G.B.

1994-01-01

PETRO.CALC.PLOT is a package of macros which normalizes whole-rock oxide data to 100%, calculates the cation percentages and molecular proportions used for normative mineral calculations, computes the apices for ternary diagrams, determines sums and ratios of specific elements of petrologic interest, and plots 33 X-Y graphs and five ternary diagrams. PETRO.CALC.PLOT also may be used to create other diagrams as desired by the user. The macros run in Microsoft Excel 3.0 and 4.0 for Macintosh computers and in Microsoft Excel 3.0 and 4.0 for Windows. Macros provided in PETRO.CALC.PLOT minimize repetition and time required to recalculate and plot whole-rock oxide data for petrologic analysis. ?? 1994.

Ordered macro-microporous metal-organic framework single crystals

NASA Astrophysics Data System (ADS)

Shen, Kui; Zhang, Lei; Chen, Xiaodong; Liu, Lingmei; Zhang, Daliang; Han, Yu; Chen, Junying; Long, Jilan; Luque, Rafael; Li, Yingwei; Chen, Banglin

2018-01-01

We constructed highly oriented and ordered macropores within metal-organic framework (MOF) single crystals, opening up the area of three-dimensional–ordered macro-microporous materials (that is, materials containing both macro- and micropores) in single-crystalline form. Our methodology relies on the strong shaping effects of a polystyrene nanosphere monolith template and a double-solvent–induced heterogeneous nucleation approach. This process synergistically enabled the in situ growth of MOFs within ordered voids, rendering a single crystal with oriented and ordered macro-microporous structure. The improved mass diffusion properties of such hierarchical frameworks, together with their robust single-crystalline nature, endow them with superior catalytic activity and recyclability for bulky-molecule reactions, as compared with conventional, polycrystalline hollow, and disordered macroporous ZIF-8.

On the predictivity of pore-scale simulations: Estimating uncertainties with multilevel Monte Carlo

NASA Astrophysics Data System (ADS)

Icardi, Matteo; Boccardo, Gianluca; Tempone, Raúl

2016-09-01

A fast method with tunable accuracy is proposed to estimate errors and uncertainties in pore-scale and Digital Rock Physics (DRP) problems. The overall predictivity of these studies can be, in fact, hindered by many factors including sample heterogeneity, computational and imaging limitations, model inadequacy and not perfectly known physical parameters. The typical objective of pore-scale studies is the estimation of macroscopic effective parameters such as permeability, effective diffusivity and hydrodynamic dispersion. However, these are often non-deterministic quantities (i.e., results obtained for specific pore-scale sample and setup are not totally reproducible by another ;equivalent; sample and setup). The stochastic nature can arise due to the multi-scale heterogeneity, the computational and experimental limitations in considering large samples, and the complexity of the physical models. These approximations, in fact, introduce an error that, being dependent on a large number of complex factors, can be modeled as random. We propose a general simulation tool, based on multilevel Monte Carlo, that can reduce drastically the computational cost needed for computing accurate statistics of effective parameters and other quantities of interest, under any of these random errors. This is, to our knowledge, the first attempt to include Uncertainty Quantification (UQ) in pore-scale physics and simulation. The method can also provide estimates of the discretization error and it is tested on three-dimensional transport problems in heterogeneous materials, where the sampling procedure is done by generation algorithms able to reproduce realistic consolidated and unconsolidated random sphere and ellipsoid packings and arrangements. A totally automatic workflow is developed in an open-source code [1], that include rigid body physics and random packing algorithms, unstructured mesh discretization, finite volume solvers, extrapolation and post-processing techniques. The proposed method can be efficiently used in many porous media applications for problems such as stochastic homogenization/upscaling, propagation of uncertainty from microscopic fluid and rock properties to macro-scale parameters, robust estimation of Representative Elementary Volume size for arbitrary physics.

Autophagy and Cancer

PubMed Central

Mah, Li Yen; Ryan, Kevin M.

2012-01-01

(Macro)autophagy is a cellular membrane trafficking process that serves to deliver cytoplasmic constituents to lysosomes for degradation. At basal levels, it is critical for maintaining cytoplasmic as well as genomic integrity and is therefore key to maintaining cellular homeostasis. Autophagy is also highly adaptable and can be modified to digest specific cargoes to bring about selective effects in response to numerous forms of intracellular and extracellular stress. It is not a surprise, therefore, that autophagy has a fundamental role in cancer and that perturbations in autophagy can contribute to malignant disease. We review here the roles of autophagy in various aspects of tumor suppression including the response of cells to nutrient and hypoxic stress, the control of programmed cell death, and the connection to tumor-associated immune responses. PMID:22166310

Impact of reconstruction parameters on quantitative I-131 SPECT

NASA Astrophysics Data System (ADS)

van Gils, C. A. J.; Beijst, C.; van Rooij, R.; de Jong, H. W. A. M.

2016-07-01

Radioiodine therapy using I-131 is widely used for treatment of thyroid disease or neuroendocrine tumors. Monitoring treatment by accurate dosimetry requires quantitative imaging. The high energy photons however render quantitative SPECT reconstruction challenging, potentially requiring accurate correction for scatter and collimator effects. The goal of this work is to assess the effectiveness of various correction methods on these effects using phantom studies. A SPECT/CT acquisition of the NEMA IEC body phantom was performed. Images were reconstructed using the following parameters: (1) without scatter correction, (2) with triple energy window (TEW) scatter correction and (3) with Monte Carlo-based scatter correction. For modelling the collimator-detector response (CDR), both (a) geometric Gaussian CDRs as well as (b) Monte Carlo simulated CDRs were compared. Quantitative accuracy, contrast to noise ratios and recovery coefficients were calculated, as well as the background variability and the residual count error in the lung insert. The Monte Carlo scatter corrected reconstruction method was shown to be intrinsically quantitative, requiring no experimentally acquired calibration factor. It resulted in a more accurate quantification of the background compartment activity density compared with TEW or no scatter correction. The quantification error relative to a dose calibrator derived measurement was found to be  <1%,-26% and 33%, respectively. The adverse effects of partial volume were significantly smaller with the Monte Carlo simulated CDR correction compared with geometric Gaussian or no CDR modelling. Scatter correction showed a small effect on quantification of small volumes. When using a weighting factor, TEW correction was comparable to Monte Carlo reconstruction in all measured parameters, although this approach is clinically impractical since this factor may be patient dependent. Monte Carlo based scatter correction including accurately simulated CDR modelling is the most robust and reliable method to reconstruct accurate quantitative iodine-131 SPECT images.

FW-CADIS Method for Global and Semi-Global Variance Reduction of Monte Carlo Radiation Transport Calculations

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

Wagner, John C; Peplow, Douglas E.; Mosher, Scott W

2014-01-01

This paper presents a new hybrid (Monte Carlo/deterministic) method for increasing the efficiency of Monte Carlo calculations of distributions, such as flux or dose rate distributions (e.g., mesh tallies), as well as responses at multiple localized detectors and spectra. This method, referred to as Forward-Weighted CADIS (FW-CADIS), is an extension of the Consistent Adjoint Driven Importance Sampling (CADIS) method, which has been used for more than a decade to very effectively improve the efficiency of Monte Carlo calculations of localized quantities, e.g., flux, dose, or reaction rate at a specific location. The basis of this method is the development ofmore » an importance function that represents the importance of particles to the objective of uniform Monte Carlo particle density in the desired tally regions. Implementation of this method utilizes the results from a forward deterministic calculation to develop a forward-weighted source for a deterministic adjoint calculation. The resulting adjoint function is then used to generate consistent space- and energy-dependent source biasing parameters and weight windows that are used in a forward Monte Carlo calculation to obtain more uniform statistical uncertainties in the desired tally regions. The FW-CADIS method has been implemented and demonstrated within the MAVRIC sequence of SCALE and the ADVANTG/MCNP framework. Application of the method to representative, real-world problems, including calculation of dose rate and energy dependent flux throughout the problem space, dose rates in specific areas, and energy spectra at multiple detectors, is presented and discussed. Results of the FW-CADIS method and other recently developed global variance reduction approaches are also compared, and the FW-CADIS method outperformed the other methods in all cases considered.« less

Reusable Space Vehicle Ground Operations Baseline Conceptual Model

DTIC Science & Technology

2004-03-01

Micro .........................................................................129 Figure B-91. Lower Forward Fuselage Macro...129 Figure B-92. Lower Forward Fuselage Micro ...Fuselage Micro ................................................................130 Figure B-95. Lower Wing Macro

Monte Carlo simulation of energy-dispersive x-ray fluorescence and applications

NASA Astrophysics Data System (ADS)

Li, Fusheng

Four key components with regards to Monte Carlo Library Least Squares (MCLLS) have been developed by the author. These include: a comprehensive and accurate Monte Carlo simulation code - CEARXRF5 with Differential Operators (DO) and coincidence sampling, Detector Response Function (DRF), an integrated Monte Carlo - Library Least-Squares (MCLLS) Graphical User Interface (GUI) visualization System (MCLLSPro) and a new reproducible and flexible benchmark experiment setup. All these developments or upgrades enable the MCLLS approach to be a useful and powerful tool for a tremendous variety of elemental analysis applications. CEARXRF, a comprehensive and accurate Monte Carlo code for simulating the total and individual library spectral responses of all elements, has been recently upgraded to version 5 by the author. The new version has several key improvements: input file format fully compatible with MCNP5, a new efficient general geometry tracking code, versatile source definitions, various variance reduction techniques (e.g. weight window mesh and splitting, stratifying sampling, etc.), a new cross section data storage and accessing method which improves the simulation speed by a factor of four and new cross section data, upgraded differential operators (DO) calculation capability, and also an updated coincidence sampling scheme which including K-L and L-L coincidence X-Rays, while keeping all the capabilities of the previous version. The new Differential Operators method is powerful for measurement sensitivity study and system optimization. For our Monte Carlo EDXRF elemental analysis system, it becomes an important technique for quantifying the matrix effect in near real time when combined with the MCLLS approach. An integrated visualization GUI system has been developed by the author to perform elemental analysis using iterated Library Least-Squares method for various samples when an initial guess is provided. This software was built on the Borland C++ Builder platform and has a user-friendly interface to accomplish all qualitative and quantitative tasks easily. That is to say, the software enables users to run the forward Monte Carlo simulation (if necessary) or use previously calculated Monte Carlo library spectra to obtain the sample elemental composition estimation within a minute. The GUI software is easy to use with user-friendly features and has the capability to accomplish all related tasks in a visualization environment. It can be a powerful tool for EDXRF analysts. A reproducible experiment setup has been built and experiments have been performed to benchmark the system. Two types of Standard Reference Materials (SRM), stainless steel samples from National Institute of Standards and Technology (NIST) and aluminum alloy samples from Alcoa Inc., with certified elemental compositions, are tested with this reproducible prototype system using a 109Cd radioisotope source (20mCi) and a liquid nitrogen cooled Si(Li) detector. The results show excellent agreement between the calculated sample compositions and their reference values and the approach is very fast.

Signal pulse emulation for scintillation detectors using Geant4 Monte Carlo with light tracking simulation

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

Ogawara, R.; Ishikawa, M., E-mail: masayori@med.hokudai.ac.jp

The anode pulse of a photomultiplier tube (PMT) coupled with a scintillator is used for pulse shape discrimination (PSD) analysis. We have developed a novel emulation technique for the PMT anode pulse based on optical photon transport and a PMT response function. The photon transport was calculated using Geant4 Monte Carlo code and the response function with a BC408 organic scintillator. The obtained percentage RMS value of the difference between the measured and simulated pulse with suitable scintillation properties using GSO:Ce (0.4, 1.0, 1.5 mol%), LaBr{sub 3}:Ce and BGO scintillators were 2.41%, 2.58%, 2.16%, 2.01%, and 3.32%, respectively. The proposedmore » technique demonstrates high reproducibility of the measured pulse and can be applied to simulation studies of various radiation measurements.« less

Thermo-Oxidative Induced Damage in Polymer Composites: Microstructure Image-Based Multi-Scale Modeling and Experimental Validation

NASA Astrophysics Data System (ADS)

Hussein, Rafid M.; Chandrashekhara, K.

2017-11-01

A multi-scale modeling approach is presented to simulate and validate thermo-oxidation shrinkage and cracking damage of a high temperature polymer composite. The multi-scale approach investigates coupled transient diffusion-reaction and static structural at macro- to micro-scale. The micro-scale shrinkage deformation and cracking damage are simulated and validated using 2D and 3D simulations. Localized shrinkage displacement boundary conditions for the micro-scale simulations are determined from the respective meso- and macro-scale simulations, conducted for a cross-ply laminate. The meso-scale geometrical domain and the micro-scale geometry and mesh are developed using the object oriented finite element (OOF). The macro-scale shrinkage and weight loss are measured using unidirectional coupons and used to build the macro-shrinkage model. The cross-ply coupons are used to validate the macro-shrinkage model by the shrinkage profiles acquired using scanning electron images at the cracked surface. The macro-shrinkage model deformation shows a discrepancy when the micro-scale image-based cracking is computed. The local maximum shrinkage strain is assumed to be 13 times the maximum macro-shrinkage strain of 2.5 × 10-5, upon which the discrepancy is minimized. The microcrack damage of the composite is modeled using a static elastic analysis with extended finite element and cohesive surfaces by considering the modulus spatial evolution. The 3D shrinkage displacements are fed to the model using node-wise boundary/domain conditions of the respective oxidized region. Microcrack simulation results: length, meander, and opening are closely matched to the crack in the area of interest for the scanning electron images.

The BBN Knowledge Acquisition Project

DTIC Science & Technology

1988-09-01

Optation 17 S . Large-Scale Revisions of Knowledge Bases 19 5.1 The Macro and Structure Editor 19 5.2 Developing Macro Editing Procedre 20 5.2.1 Macro...consistency checking foreach style of representaton easier and mote efficient, so that knowledge engineers and subject matter expert s can work together to... s ~Ta OIM-iJC ~Va Coetnin: MILECSXCT 8.1.3.1 Local Comumand Menus Anytime ICREM ais~laying a view of a particular kind of knowledge , the State Winsdow

MacroH2A1 associates with nuclear lamina and maintains chromatin architecture in mouse liver cells.

PubMed

Fu, Yuhua; Lv, Pin; Yan, Guoquan; Fan, Hui; Cheng, Lu; Zhang, Feng; Dang, Yongjun; Wu, Hao; Wen, Bo

2015-11-25

In the interphase nucleus, chromatin is organized into three-dimensional conformation to coordinate genome functions. The lamina-chromatin association is important to facilitate higher-order chromatin in mammalian cells, but its biological significances and molecular mechanisms remain poorly understood. One obstacle is that the list of lamina-associated proteins remains limited, presumably due to the inherent insolubility of lamina proteins. In this report, we identified 182 proteins associated with lamin B1 (a constitutive component of lamina) in mouse hepatocytes, by adopting virus-based proximity-dependent biotin identification. These proteins are functionally related to biological processes such as chromatin organization. As an example, we validated the association between lamin B1 and core histone macroH2A1, a histone associated with repressive chromatin. Furthermore, we mapped Lamina-associated domains (LADs) in mouse liver cells and found that boundaries of LADs are enriched for macroH2A. More interestingly, knocking-down of macroH2A1 resulted in the release of heterochromatin foci marked by histone lysine 9 trimethylation (H3K9me3) and the decondensation of global chromatin structure. However, down-regulation of lamin B1 led to redistribution of macroH2A1. Taken together, our data indicated that macroH2A1 is associated with lamina and is required to maintain chromatin architecture in mouse liver cells.

The role of collaboration in facilitating policy change in youth violence prevention: a review of the literature.

PubMed

Sugimoto-Matsuda, Jeanelle J; Braun, Kathryn L

2014-04-01

Youth violence remains a serious public health issue nationally and internationally. The social ecological model has been recommended as a framework to design youth violence prevention initiatives, requiring interventions at the micro-, meso-, exo-, and macro-levels. However, documentation of interventions at the macro-level, particularly those that address policy issues, is limited. This study examines a recommendation in the literature that formalized collaborations play a vital role in stimulating macro-level policy change. The purpose of this systematic literature review is to examine existing youth violence prevention collaborations and evaluate their policy-related outcomes. The search found 23 unique collaborations focused on youth violence prevention. These were organized into three groups based on the "catalyst" for action for the collaboration-internal (momentum began within the community), external (sparked by an external agency), or policy (mandated by law). Findings suggest that internally catalyzed collaborations were most successful at changing laws to address youth violence, while both internally and externally catalyzed collaborations successfully attained policy change at the organizational level. A conceptual model is proposed, describing a potential pathway for achieving macro-level change via collaboration. Recommendations for future research and practice are suggested, including expansion of this study to capture additional collaborations, investigation of macro-level changes with a primary prevention focus, and improvement of evaluation, dissemination, and translation of macro-level initiatives.

The Role of Collaboration in Facilitating Policy Change in Youth Violence Prevention: a Review of the Literature

PubMed Central

Braun, Kathryn L.

2015-01-01

Youth violence remains a serious public health issue nationally and internationally. The social ecological model has been recommended as a framework to design youth violence prevention initiatives, requiring interventions at the micro-, meso-, exo-, and macro-levels. However, documentation of interventions at the macro-level, particularly those that address policy issues, is limited. This study examines a recommendation in the literature that formalized collaborations play a vital role in stimulating macro-level policy change. The purpose of this systematic literature review is to examine existing youth violence prevention collaborations and evaluate their policy-related outcomes. The search found 23 unique collaborations focused on youth violence prevention. These were organized into three groups based on the “catalyst” for action for the collaboration—internal (momentum began with-in the community), external (sparked by an external agency), or policy (mandated by law). Findings suggest that internally catalyzed collaborations were most successful at changing laws to address youth violence, while both internally and externally catalyzed collaborations successfully attained policy change at the organizational level. A conceptual model is proposed, describing a potential pathway for achieving macro-level change via collaboration. Recommendations for future research and practice are suggested, including expansion of this study to capture additional collaborations, investigation of macro-level changes with a primary prevention focus, and improvement of evaluation, dissemination, and translation of macro-level initiatives. PMID:23430580

Permeability of Granite Including Macro-Fracture Naturally Filled with Fine-Grained Minerals

NASA Astrophysics Data System (ADS)

Nara, Yoshitaka; Kato, Masaji; Niri, Ryuhei; Kohno, Masanori; Sato, Toshinori; Fukuda, Daisuke; Sato, Tsutomu; Takahashi, Manabu

2018-03-01

Information on the permeability of rock is essential for various geoengineering projects, such as geological disposal of radioactive wastes, hydrocarbon extraction, and natural hazard risk mitigation. It is especially important to investigate how fractures and pores influence the physical and transport properties of rock. Infiltration of groundwater through the damage zone fills fractures in granite with fine-grained minerals. However, the permeability of rock possessing a fracture naturally filled with fine-grained mineral grains has yet to be investigated. In this study, the permeabilities of granite samples, including a macro-fracture filled with clay and a mineral vein, are investigated. The permeability of granite with a fine-grained mineral vein agrees well with that of the intact sample, whereas the permeability of granite possessing a macro-fracture filled with clay is lower than that of the macro-fractured sample. The decrease in the permeability is due to the filling of fine-grained minerals and clay in the macro-fracture. It is concluded that the permeability of granite increases due to the existence of the fractures, but decreases upon filling them with fine-grained minerals.

Data-Science Analysis of the Macro-scale Features Governing the Corrosion to Crack Transition in AA7050-T7451

NASA Astrophysics Data System (ADS)

Co, Noelle Easter C.; Brown, Donald E.; Burns, James T.

2018-05-01

This study applies data science approaches (random forest and logistic regression) to determine the extent to which macro-scale corrosion damage features govern the crack formation behavior in AA7050-T7451. Each corrosion morphology has a set of corresponding predictor variables (pit depth, volume, area, diameter, pit density, total fissure length, surface roughness metrics, etc.) describing the shape of the corrosion damage. The values of the predictor variables are obtained from white light interferometry, x-ray tomography, and scanning electron microscope imaging of the corrosion damage. A permutation test is employed to assess the significance of the logistic and random forest model predictions. Results indicate minimal relationship between the macro-scale corrosion feature predictor variables and fatigue crack initiation. These findings suggest that the macro-scale corrosion features and their interactions do not solely govern the crack formation behavior. While these results do not imply that the macro-features have no impact, they do suggest that additional parameters must be considered to rigorously inform the crack formation location.

An new MHD/kinetic model for exploring energetic particle production in macro-scale systems

NASA Astrophysics Data System (ADS)

Drake, J. F.; Swisdak, M.; Dahlin, J. T.

2017-12-01

A novel MHD/kinetic model is being developed to explore magneticreconnection and particle energization in macro-scale systems such asthe solar corona and the outer heliosphere. The model blends the MHDdescription with a macro-particle description. The rationale for thismodel is based on the recent discovery that energetic particleproduction during magnetic reconnection is controlled by Fermireflection and Betatron acceleration and not parallel electricfields. Since the former mechanisms are not dependent on kineticscales such as the Debye length and the electron and ion inertialscales, a model that sheds these scales is sufficient for describingparticle acceleration in macro-systems. Our MHD/kinetic model includesmacroparticles laid out on an MHD grid that are evolved with the MHDfields. Crucially, the feedback of the energetic component on the MHDfluid is included in the dynamics. Thus, energy of the total system,the MHD fluid plus the energetic component, is conserved. The systemhas no kinetic scales and therefore can be implemented to modelenergetic particle production in macro-systems with none of theconstraints associated with a PIC model. Tests of the new model insimple geometries will be presented and potential applications will bediscussed.

SAS macro programs for geographically weighted generalized linear modeling with spatial point data: applications to health research.

PubMed

Chen, Vivian Yi-Ju; Yang, Tse-Chuan

2012-08-01

An increasing interest in exploring spatial non-stationarity has generated several specialized analytic software programs; however, few of these programs can be integrated natively into a well-developed statistical environment such as SAS. We not only developed a set of SAS macro programs to fill this gap, but also expanded the geographically weighted generalized linear modeling (GWGLM) by integrating the strengths of SAS into the GWGLM framework. Three features distinguish our work. First, the macro programs of this study provide more kernel weighting functions than the existing programs. Second, with our codes the users are able to better specify the bandwidth selection process compared to the capabilities of existing programs. Third, the development of the macro programs is fully embedded in the SAS environment, providing great potential for future exploration of complicated spatially varying coefficient models in other disciplines. We provided three empirical examples to illustrate the use of the SAS macro programs and demonstrated the advantages explained above. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Sulfonated macro-RAFT agents for the surfactant-free synthesis of cerium oxide-based hybrid latexes.

PubMed

Garnier, Jérôme; Warnant, Jérôme; Lacroix-Desmazes, Patrick; Dufils, Pierre-Emmanuel; Vinas, Jérôme; van Herk, Alex

2013-10-01

Three types of amphiphatic macro-RAFT agents were employed as compatibilizers to promote the polymerization reaction at the surface of nanoceria for the synthesis of CeO2-based hybrid latexes. Macro-RAFT copolymers and terpolymers were first synthesized employing various combinations of butyl acrylate as a hydrophobic monomer and acrylic acid (AA) and/or 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as hydrophilic monomers. After characterizing the adsorption of these macro-RAFT agents at the cerium oxide surface by UV-visible spectrometry, emulsion copolymerization reactions of styrene and methyl acrylate were then carried out in the presence of the surface-modified nanoceria. Dynamic Light Scattering and cryo-Transmission Electron Microscopy were employed to confirm the hybrid structure of the final CeO2/polymer latexes, and proved that the presence of acrylic acid units in amphiphatic macro-RAFT agents enabled an efficient formation of hybrid structures, while the presence of AMPS units, when combined with AA units, resulted in a better distribution of cerium oxide nanoclusters between latex particles. Copyright © 2013 Elsevier Inc. All rights reserved.

A Bayesian Approach to Person Fit Analysis in Item Response Theory Models. Research Report.

ERIC Educational Resources Information Center

Glas, Cees A. W.; Meijer, Rob R.

A Bayesian approach to the evaluation of person fit in item response theory (IRT) models is presented. In a posterior predictive check, the observed value on a discrepancy variable is positioned in its posterior distribution. In a Bayesian framework, a Markov Chain Monte Carlo procedure can be used to generate samples of the posterior distribution…

Signal-transfer Modeling for Regional Assessment of Forest Responses to Environmental Changes in the Southeastern United States

Treesearch

Robert J. Luxmoore; William W. Hargrove; M. Lynn Tharp; Wilfred M. Post; Michael W. Berry; Karen S. Minser; Wendell P. Cropper; Dale W. Johnson; Boris Zeide; Ralph L. Amateis; Harold E. Burkhart; V. Clark Baldwin; Kelly D. Peterson

2000-01-01

Stochastic transfer of information in a hierarchy of simulators is offered as a conceptual approach for assessing forest responses to changing climate and air quality across 13 southeastern states of the USA. This assessment approach combines geographic information system and Monte Carlo capabilities with several scales of computer modeling for southern pine species...

Asymmetric information and macroeconomic dynamics

NASA Astrophysics Data System (ADS)

Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

2010-09-01

We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

EGRET High Energy Capability and Multiwavelength Flare Studies and Solar Flare Proton Spectra

NASA Technical Reports Server (NTRS)

Chupp, Edward L.

1997-01-01

UNH was assigned the responsibility to use their accelerator neutron measurements to verify the TASC response function and to modify the TASC fitting program to include a high energy neutron contribution. Direct accelerator-based measurements by UNH of the energy-dependent efficiencies for detecting neutrons with energies from 36 to 720 MeV in NaI were compared with Monte Carlo TASC calculations. The calculated TASC efficiencies are somewhat lower (by about 20%) than the accelerator results in the energy range 70-300 MeV. The measured energy-loss spectrum for 207 MeV neutron interactions in NaI were compared with the Monte Carlo response for 200 MeV neutrons in the TASC indicating good agreement. Based on this agreement, the simulation was considered to be sufficiently accurate to generate a neutron response library to be used by UNH in modifying the TASC fitting program to include a neutron component in the flare spectrum modeling. TASC energy-loss data on the 1991 June 11 flare was transferred to UNH. Also included appendix: Gamma-rays and neutrons as a probe of flare proton spectra: the solar flare of 11 June 1991.

Dose response evaluation of a low-density normoxic polymer gel dosimeter using MRI

NASA Astrophysics Data System (ADS)

Haraldsson, P.; Karlsson, A.; Wieslander, E.; Gustavsson, H.; Bäck, S. Å. J.

2006-02-01

A low-density (~0.6 g cm-3) normoxic polymer gel, containing the antioxidant tetrakis (hydroxymethyl) phosponium (THP), has been investigated with respect to basic absorbed dose response characteristics. The low density was obtained by mixing the gel with expanded polystyrene spheres. The depth dose data for 6 and 18 MV photons were compared with Monte Carlo calculations. A large volume phantom was irradiated in order to study the 3D dose distribution from a 6 MV field. Evaluation of the gel was carried out using magnetic resonance imaging. An approximately linear response was obtained for 1/T2 versus dose in the dose range of 2 to 8 Gy. A small decrease in the dose response was observed for increasing concentrations of THP. A good agreement between measured and Monte Carlo calculated data was obained, both for test tubes and the larger 3D phantom. It was shown that a normoxic polymer gel with a reduced density could be obtained by adding expanded polystyrene spheres. In order to get reliable results, it is very important to have a uniform distribution of the gel and expanded polystyrene spheres in the phantom volume.

Dose response of alanine detectors irradiated with carbon ion beams

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

Herrmann, Rochus; Jaekel, Oliver; Palmans, Hugo

Purpose: The dose response of the alanine detector shows a dependence on particle energy and type when irradiated with ion beams. The purpose of this study is to investigate the response behavior of the alanine detector in clinical carbon ion beams and compare the results to model predictions. Methods: Alanine detectors have been irradiated with carbon ions with an energy range of 89-400 MeV/u. The relative effectiveness of alanine has been measured in this regime. Pristine and spread out Bragg peak depth-dose curves have been measured with alanine dosimeters. The track structure based alanine response model developed by Hansen andmore » Olsen has been implemented in the Monte Carlo code FLUKA and calculations were compared to experimental results. Results: Calculations of the relative effectiveness deviate less than 5% from the measured values for monoenergetic beams. Measured depth-dose curves deviate from predictions in the peak region, most pronounced at the distal edge of the peak. Conclusions: The used model and its implementation show a good overall agreement for quasimonoenergetic measurements. Deviations in depth-dose measurements are mainly attributed to uncertainties of the detector geometry implemented in the Monte Carlo simulations.« less

Promoting change through political consciousness: a South African speech-language pathology response to the World Report on Disability.

PubMed

Kathard, Harsha; Pillay, Mershen

2013-02-01

In the context of the World Report on Disability, Wylie, McAllister, Davidson, and Marshall (2013) question how speech-language pathologists (SLPs) change practices to benefit under-served people with communication disability. This commentary provides a South African response premised on Political Consciousness. In South Africa, a grossly unequal society, the under-served population is not only those with communication disability but also include those who are at a communication disadvantage due to disabling conditions. As a consequence of the combined effects of a severe shortage of SLPs as well as maldistribution in service provision, the under-served are mainly poor Black South Africans who are the majority population. Political Consciousness allows one to examine how selected forces at the macro-level, meso-level, and micro-level may enable or limit services to the under-served majority. At a macro-level, this study appraises policies and actions advancing and impeding service delivery. At the meso-level it is argued that hegemonic professional knowledge is limiting and an equity-driven population-based approach is advocated. At a micro-level, the Relationship of Labouring Affinities is offered as a conceptual tool for critical engagement. In conclusion, it is suggested that the speech-language pathology profession must collectively become political actors at all levels to effect change.

Abuse of disabled parking: Reforming public's attitude through persuasive multimedia strategy

NASA Astrophysics Data System (ADS)

Yahaya, W. A. J. W.; Zain, M. Z. M.

2014-02-01

Attitude is one of the factors that contribute to the abuse of disabled parking. The attitude's components are affective, cognitive and behavioral and may be formed in various ways including learning and persuasion. Using learning and persuasion approach, this study has produced a persuasive multimedia aiming to form a positive attitude toward disabled persons in order to minimize the rate of disabled parking abuse. The persuasive multimedia was developed using Principle of Social Learning draws from Persuasive Technology as learning strategy at macro persuasion level, and modality and redundancy principles draw from Multimedia Learning Principles as design strategy at micro persuasion level. In order to measure the effectiveness of the persuasive multimedia, 93 respondents were selected in a 2 × 2 quasi experimental research design for experiment. Attitude components of affective, cognitive and behavioral were measured using adapted instrument from the Multi Dimensional Attitudes Scale toward Persons With Disabilities (MAS). Result of the study shows that the persuasive multimedia which designed based on Social Learning Theory at macro persuasion level is capable of forming positive attitude toward disabled person. The cognitive component of the attitude found to be the most responsive component. In term of design strategy at the micro persuasion level, modality found to be the most significant strategy compare to redundancy. While males are more responsive to the persuasive multimedia compare to females.

Filtered cathodic arc source

DOEpatents

Falabella, S.; Sanders, D.M.

1994-01-18

A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge is described. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45[degree] to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles. 3 figures.

Filtered cathodic arc source

DOEpatents

Falabella, Steven; Sanders, David M.

1994-01-01

A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

Pattern Recognition Control Design

NASA Technical Reports Server (NTRS)

Gambone, Elisabeth

2016-01-01

Spacecraft control algorithms must know the expected spacecraft response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach can be used to investigate the relationship between the control effector commands and the spacecraft responses. Instead of supplying the approximated vehicle properties and the effector performance characteristics, a database of information relating the effector commands and the desired vehicle response can be used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands can be analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center (Ref. 1) to analyze flight dynamics Monte Carlo data sets through pattern recognition methods can be used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands is established, it can be used in place of traditional control laws and gains set. This pattern recognition approach can be compared with traditional control algorithms to determine the potential benefits and uses.

Monte Carlo study for physiological interference reduction in near-infrared spectroscopy based on empirical mode decomposition

NASA Astrophysics Data System (ADS)

Zhang, Yan; Sun, JinWei; Rolfe, Peter

2010-12-01

Near-infrared spectroscopy (NIRS) can be used as the basis of non-invasive neuroimaging that may allow the measurement of haemodynamic changes in the human brain evoked by applied stimuli. Since this technique is very sensitive, physiological interference arising from the cardiac cycle and breathing can significantly affect the signal quality. Such interference is difficult to remove by conventional techniques because it occurs not only in the extracerebral layer but also in the brain tissue itself. Previous work on this problem employing temporal filtering, spatial filtering, and adaptive filtering have exhibited good performance for recovering brain activity data in evoked response studies. However, in this study, we present a time-frequency adaptive method for physiological interference reduction based on the combination of empirical mode decomposition (EMD) and Hilbert spectral analysis (HSA). Monte Carlo simulations based on a five-layered slab model of a human adult head were implemented to evaluate our methodology. We applied an EMD algorithm to decompose the NIRS time series derived from Monte Carlo simulations into a series of intrinsic mode functions (IMFs). In order to identify the IMFs associated with symmetric interference, the extracted components were then Hilbert transformed from which the instantaneous frequencies could be acquired. By reconstructing the NIRS signal by properly selecting IMFs, we determined that the evoked brain response is effectively filtered out with even higher signal-to-noise ratio (SNR). The results obtained demonstrated that EMD, combined with HSA, can effectively separate, identify and remove the contamination from the evoked brain response obtained with NIRS using a simple single source-detector pair.

Log-normal frailty models fitted as Poisson generalized linear mixed models.

PubMed

Hirsch, Katharina; Wienke, Andreas; Kuss, Oliver

2016-12-01

The equivalence of a survival model with a piecewise constant baseline hazard function and a Poisson regression model has been known since decades. As shown in recent studies, this equivalence carries over to clustered survival data: A frailty model with a log-normal frailty term can be interpreted and estimated as a generalized linear mixed model with a binary response, a Poisson likelihood, and a specific offset. Proceeding this way, statistical theory and software for generalized linear mixed models are readily available for fitting frailty models. This gain in flexibility comes at the small price of (1) having to fix the number of pieces for the baseline hazard in advance and (2) having to "explode" the data set by the number of pieces. In this paper we extend the simulations of former studies by using a more realistic baseline hazard (Gompertz) and by comparing the model under consideration with competing models. Furthermore, the SAS macro %PCFrailty is introduced to apply the Poisson generalized linear mixed approach to frailty models. The simulations show good results for the shared frailty model. Our new %PCFrailty macro provides proper estimates, especially in case of 4 events per piece. The suggested Poisson generalized linear mixed approach for log-normal frailty models based on the %PCFrailty macro provides several advantages in the analysis of clustered survival data with respect to more flexible modelling of fixed and random effects, exact (in the sense of non-approximate) maximum likelihood estimation, and standard errors and different types of confidence intervals for all variance parameters. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Studying policy implementation using a macro, meso and micro frame analysis: the case of the Collaboration for Leadership in Applied Health Research & Care (CLAHRC) programme nationally and in North West London

PubMed Central

2012-01-01

Background The publication of Best research for best health in 2006 and the “ring-fencing” of health research funding in England marked the start of a period of change for health research governance and the structure of research funding in England. One response to bridging the ‘second translational gap’ between research knowledge and clinical practice was the establishment of nine Collaborations for Leadership in Applied Health Research and Care (CLAHRCs). The goal of this paper is to assess how national-level understanding of the aims and objectives of the CLAHRCs translated into local implementation and practice in North West London. Methods This study uses a variation of Goffman’s frame analysis to trace the development of the initial national CLAHRC policy to its implementation at three levels. Data collection and analysis were qualitative through interviews, document analysis and embedded research. Results Analysis at the macro (national policy), meso (national programme) and micro (North West London) levels shows a significant common understanding of the aims and objectives of the policy and programme. Local level implementation in North West London was also consistent with these. Conclusions The macro-meso-micro frame analysis is a useful way of studying the transition of a policy from high-level idea to programme in action. It could be used to identify differences at a local (micro) level in the implementation of multi-site programmes that would help understand differences in programme effectiveness. PMID:23067208

Effect of Irregularity in Shape and Boundary of a Macro-Texture Region in Titanium (Postprint)

DTIC Science & Technology

2015-10-15

AFRL-RX-WP-JA-2016-0328 EFFECT OF IRREGULARITY IN SHAPE AND BOUNDARY OF A MACRO-TEXTURE REGION IN TITANIUM (POSTPRINT) James L...2 October 2014 – 15 September 2015 4. TITLE AND SUBTITLE EFFECT OF IRREGULARITY IN SHAPE AND BOUNDARY OF A MACRO-TEXTURE REGION IN TITANIUM ...aerospace grade titanium alloy material are measured to be about the same level as corner trapped shear wave signals. In addition to the abnormally high

Immobilization of enzymes by bioaffinity layering.

PubMed

Singh, Veena; Sardar, Meryam; Gupta, Munishwar Nath

2013-01-01

Bioaffinity immobilization exploits the affinity of the enzyme to a macro-(affinity ligand). Such a macro-(affinity ligand) could be a lectin, a water-soluble polymer, or a bioconjugate of a water-soluble polymer and the appropriate affinity ligand. Successive layering of the enzyme and the macro-(affinity ligand) on a matrix allows deposition of a large amount of enzyme activity on a small surface. Illustrative protocols show affinity layering of a pectinase and horseradish peroxidase on Concanavalin A-agarose and Concanavalin A-Sephadex matrices, respectively.

Dynamic stereotypic responses of Basal Ganglia neurons to subthalamic nucleus high-frequency stimulation in the parkinsonian primate.

PubMed

Moran, Anan; Stein, Edward; Tischler, Hadass; Belelovsky, Katya; Bar-Gad, Izhar

2011-01-01

Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is a well-established therapy for patients with severe Parkinson's disease (PD); however, its mechanism of action is still unclear. In this study we explored static and dynamic activation patterns in the basal ganglia (BG) during high-frequency macro-stimulation of the STN. Extracellular multi-electrode recordings were performed in primates rendered parkinsonian using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Recordings were preformed simultaneously in the STN and the globus pallidus externus and internus. Single units were recorded preceding and during the stimulation. During the stimulation, STN mean firing rate dropped significantly, while pallidal mean firing rates did not change significantly. The vast majority of neurons across all three nuclei displayed stimulation driven modulations, which were stereotypic within each nucleus but differed across nuclei. The predominant response pattern of STN neurons was somatic inhibition. However, most pallidal neurons demonstrated synaptic activation patterns. A minority of neurons across all nuclei displayed axonal activation. Temporal dynamics were observed in the response to stimulation over the first 10 seconds in the STN and over the first 30 seconds in the pallidum. In both pallidal segments, the synaptic activation response patterns underwent delay and decay of the magnitude of the peak response due to short term synaptic depression. We suggest that during STN macro-stimulation the STN goes through a functional ablation as its upper bound on information transmission drops significantly. This notion is further supported by the evident dissociation between the stimulation driven pre-synaptic STN somatic inhibition and the post-synaptic axonal activation of its downstream targets. Thus, BG output maintains its firing rate while losing the deleterious effect of the STN. This may be a part of the mechanism leading to the beneficial effect of DBS in PD.

In situ calibration of neutron activation system on the large helical device

NASA Astrophysics Data System (ADS)

Pu, N.; Nishitani, T.; Isobe, M.; Ogawa, K.; Kawase, H.; Tanaka, T.; Li, S. Y.; Yoshihashi, S.; Uritani, A.

2017-11-01

In situ calibration of the neutron activation system on the Large Helical Device (LHD) was performed by using an intense 252Cf neutron source. To simulate a ring-shaped neutron source, we installed a railway inside the LHD vacuum vessel and made a train loaded with the 252Cf source run along a typical magnetic axis position. Three activation capsules loaded with thirty pieces of indium foils stacked with total mass of approximately 18 g were prepared. Each capsule was irradiated over 15 h while the train was circulating. The activation response coefficient (9.4 ± 1.2) × 10-8 of 115In(n, n')115mIn reaction obtained from the experiment is in good agreement with results from three-dimensional neutron transport calculations using the Monte Carlo neutron transport simulation code 6. The activation response coefficients of 2.45 MeV birth neutron and secondary 14.1 MeV neutron from deuterium plasma were evaluated from the activation response coefficient obtained in this calibration experiment with results from three-dimensional neutron calculations using the Monte Carlo neutron transport simulation code 6.

A probabilistic sizing tool and Monte Carlo analysis for entry vehicle ablative thermal protection systems

NASA Astrophysics Data System (ADS)

Mazzaracchio, Antonio; Marchetti, Mario

2010-03-01

Implicit ablation and thermal response software was developed to analyse and size charring ablative thermal protection systems for entry vehicles. A statistical monitor integrated into the tool, which uses the Monte Carlo technique, allows a simulation to run over stochastic series. This performs an uncertainty and sensitivity analysis, which estimates the probability of maintaining the temperature of the underlying material within specified requirements. This approach and the associated software are primarily helpful during the preliminary design phases of spacecraft thermal protection systems. They are proposed as an alternative to traditional approaches, such as the Root-Sum-Square method. The developed tool was verified by comparing the results with those from previous work on thermal protection system probabilistic sizing methodologies, which are based on an industry standard high-fidelity ablation and thermal response program. New case studies were analysed to establish thickness margins on sizing heat shields that are currently proposed for vehicles using rigid aeroshells for future aerocapture missions at Neptune, and identifying the major sources of uncertainty in the material response.

[Characteristics of ground-dwelling soil macro-arthropod communities in a biodiversity monitoring plot of black soil cropland, northeastern China].

PubMed

Liu, Jie; Gao, Mie Xiang; Wu, Dong Hui

2017-12-01

Agro-ecosystem is an important component of terrestrial ecosystems and it is one of the key areas of global ecological and environmental studies. A 16 hm 2 permanent plot in black soil cropland was built to study the community structure of soil biodiversity in typical black soil region in Northeast China. Pitfall trap was used to investigate the ground-dwelling soil macro-arthropods from August to October 2015 in accordance with the three crop growth stages: whirling stage, silking stage, and milk stage. A total of 5284 ground-dwelling soil macro-arthropods belonging to 47 species were captured sorted into 3 classes, 12 orders, 32 families. 3 dominant groups and 11 common groups were found. Phytophages and Omnivores were dominant groups. The individuals and species numbers of ground-dwelling soil macro-arthropods had significant changes with the vegetative growth period. The maximum values of the Shannon index, Margalef index, Pielou index of soil macro-arthropods all appeared in September, but the maximum dominant index appeared in August. From the variation coefficient (CV) and spatial interpolation of different species, it could be seen that there was heterogeneity in the horizontal direction of the ground-dwelling soil macro-arthropod communities. Regarding the relationships between the ground-dwelling soil macro-arthropod communities and soil environmental factors including soil pH, soil organic matter, total nitrogen and soil water content, the bivariate correlation analysis showed there was no significant correlation between them. Results of canonical correspondence analysis (CCA) further indicated that the dominant and common groups were adaptable to environmental factors and widely distributed in the study area. The results showed that the species richness of ground-dwelling soil macro-arthropods was very high in cropland, and the dynamic of soil arthropod's composition and spatial distribution pattern in diffe-rent crop growth stages were significantly changed. It was indicated that biodiversity plot monitoring of black soil cropland had become important means to solve the formation and maintenance mechanism of soil fauna community through large-scale and long-term investigation.

Molecular mechanisms in response to phosphate starvation in rice.

PubMed

Panigrahy, Madhusmita; Rao, D Nageswara; Sarla, N

2009-01-01

Phosphorus is one of the most important elements that significantly affect plant growth and metabolism. Among the macro-nutrients, phosphorus is the least available to the plants as major phosphorus content of the fertiliser is sorbed by soil particles. An increased knowledge of the regulatory mechanisms controlling plant's phosphorus status is vital for improving phosphorus uptake and P-use efficiency and for reducing excessive input of fertilisers, while maintaining an acceptable yield. Phosphorus use efficiency has been studied using forward and reverse genetic analyses of mutants, quantitative genomic approaches and whole plant physiology but all these studies need to be integrated for a clearer understanding. We provide a critical overview on the molecular mechanisms and the components involved in the plant during phosphorus starvation. Then we summarize the information available on the genes and QTLs involved in phosphorus signalling and also the methods to estimate total phosphate in plant tissue. Also, an effort is made to build a comprehensive picture of phosphorus uptake, homeostasis, assimilation, remobilization, its deposition in the grain and its interaction with other micro- and macro-nutrients as well as phytohormones.

Meso-scopic Densification in Brittle Granular Materials

NASA Astrophysics Data System (ADS)

Neal, William; Appleby-Thomas, Gareth; Collins, Gareth

2013-06-01

Particulate materials are ideally suited to shock absorbing applications due to the large amounts of energy required to deform their inherently complex meso-structure. Significant effort is being made to improve macro-scale material models to represent these atypical materials. On the long road towards achieving this capability, an important milestone would be to understand how particle densification mechanisms are affected by loading rate. In brittle particulate materials, the majority of densification is caused by particle fracture. Macro-scale quasi-static and dynamic compaction curves have been measured that show good qualitative agreement. There are, however, some differences that appear to be dependent on the loading rate that require further investigation. This study aims to investigate the difference in grain-fracture behavior between the quasi-static and shock loading response of brittle glass microsphere beds using a combination of quasi-static and dynamic loading techniques. Results from pressure-density measurements, sample recovery, and meso-scale hydrocode models (iSALE, an in-house simulation package) are discussed to explain the differences in particle densification mechanisms between the two loading rate regimes. Gratefully funded by AWE.plc.

The Modulatable Stem Cell Niche: Tissue Interactions during Hair and Feather Follicle Regeneration.

PubMed

Chen, Chih-Chiang; Plikus, Maksim V; Tang, Pin-Chi; Widelitz, Randall B; Chuong, Cheng Ming

2016-04-10

Hair and feathers are unique because (1) their stem cells are contained within a follicle structure, (2) they undergo cyclic regeneration repetitively throughout life, (3) regeneration occurs physiologically in healthy individuals and (4) regeneration is also induced in response to injury. Precise control of this cyclic regeneration process is essential for maintaining the homeostasis of living organisms. While stem cells are regulated by the intra-follicle-adjacent micro-environmental niche, this niche is also modulated dynamically by extra-follicular macro-environmental signals, allowing stem cells to adapt to a larger changing environment and physiological needs. Here we review several examples of macro-environments that communicate with the follicles: intradermal adipose tissue, innate immune system, sex hormones, aging, circadian rhythm and seasonal rhythms. Related diseases are also discussed. Unveiling the mechanisms of how stem cell niches are modulated provides clues for regenerative medicine. Given that stem cells are hard to manipulate, focusing translational therapeutic applications at the environments appears to be a more practical approach. Copyright © 2015 Elsevier Ltd. All rights reserved.

Confined Floodplain Dynamics on Semi-Arid Systems

NASA Astrophysics Data System (ADS)

Entwistle, N. S.

2017-12-01

Many watercourses across southern Africa are characterised by a bedrock influenced `macro-channel' created as a result of geologically recent fluvial incision into ancient planation surfaces. The rivers of the Kruger National Park in Mpumalanga Province, South Africa are no exception, displaying a varied set of channel types within a bedrock template. Contemporary flows are largely contained within the confines of this `macro-channel' and a diverse valley bottom morphology and ecology has developed in response to this flow regime coupled with intermittent fine sediment delivery from the catchment. Aerial imagery and field monitoring of the impact of two cyclone driven extreme flows and subsequent recovery phases suggests that flood impact is spatially variable with bedrock exposure greatest along watercourses already severely impacted by previous events. Subsequent system development has been characterised by the redistribution and vegetative colonisation of unconsolidated sandy sediment over bedrock. On less impacted systems vegetative induced recovery has, in contrast, been rapid with many of the species present displaying significant resilience to extreme flows forming residual pockets which are subsequently developing alongside embryonic morphologic recovery. Using these observations a model of valley bottom recovery is presented.

Macro Scale Independently Homogenized Subcells for Modeling Braided Composites

NASA Technical Reports Server (NTRS)

Blinzler, Brina J.; Goldberg, Robert K.; Binienda, Wieslaw K.

2012-01-01

An analytical method has been developed to analyze the impact response of triaxially braided carbon fiber composites, including the penetration velocity and impact damage patterns. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. Currently, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. To determine the stiffness and strength properties required for the constitutive model, a top-down approach for determining the strength properties is merged with a bottom-up approach for determining the stiffness properties. The top-down portion uses global strengths obtained from macro-scale coupon level testing to characterize the material strengths for each subcell. The bottom-up portion uses micro-scale fiber and matrix stiffness properties to characterize the material stiffness for each subcell. Simulations of quasi-static coupon level tests for several representative composites are conducted along with impact simulations.

Self-powered integrated systems-on-chip (energy chip)

NASA Astrophysics Data System (ADS)

Hussain, M. M.; Fahad, H.; Rojas, J.; Hasan, M.; Talukdar, A.; Oommen, J.; Mink, J.

2010-04-01

In today's world, consumer driven technology wants more portable electronic gadgets to be developed, and the next big thing in line is self-powered handheld devices. Therefore to reduce the power consumption as well as to supply sufficient power to run those devices, several critical technical challenges need to be overcome: a. Nanofabrication of macro/micro systems which incorporates the direct benefit of light weight (thus portability), low power consumption, faster response, higher sensitivity and batch production (low cost). b. Integration of advanced nano-materials to meet the performance/cost benefit trend. Nano-materials may offer new functionalities that were previously underutilized in the macro/micro dimension. c. Energy efficiency to reduce power consumption and to supply enough power to meet that low power demand. We present a pragmatic perspective on a self-powered integrated System on Chip (SoC). We envision the integrated device will have two objectives: low power consumption/dissipation and on-chip power generation for implementation into handheld or remote technologies for defense, space, harsh environments and medical applications. This paper provides insight on materials choices, intelligent circuit design, and CMOS compatible integration.

Design-based modeling of magnetically actuated soft diaphragm materials

NASA Astrophysics Data System (ADS)

Jayaneththi, V. R.; Aw, K. C.; McDaid, A. J.

2018-04-01

Magnetic polymer composites (MPC) have shown promise for emerging biomedical applications such as lab-on-a-chip and implantable drug delivery. These soft material actuators are capable of fast response, large deformation and wireless actuation. Existing MPC modeling approaches are computationally expensive and unsuitable for rapid design prototyping and real-time control applications. This paper proposes a macro-scale 1-DOF model capable of predicting force and displacement of an MPC diaphragm actuator. Model validation confirmed both blocked force and displacement can be accurately predicted in a variety of working conditions i.e. different magnetic field strengths, static/dynamic fields, and gap distances. The contribution of this work includes a comprehensive experimental investigation of a macro-scale diaphragm actuator; the derivation and validation of a new phenomenological model to describe MPC actuation; and insights into the proposed model’s design-based functionality i.e. scalability and generalizability in terms of magnetic filler concentration and diaphragm diameter. Due to the lumped element modeling approach, the proposed model can also be adapted to alternative actuator configurations, and thus presents a useful tool for design, control and simulation of novel MPC applications.

SCINFUL: A Monte Carlo based computer program to determine a scintillator full energy response to neutron detection for E/sub n/ between 0. 1 and 80 MeV: Program development and comparisons of program predictions with experimental data

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

Dickens, J.K.

1988-04-01

This document provides a discussion of the development of the FORTRAN Monte Carlo program SCINFUL (for scintillator full response), a program designed to provide a calculated full response anticipated for either an NE-213 (liquid) scintillator or an NE-110 (solid) scintillator. The program may also be used to compute angle-integrated spectra of charged particles (p, d, t, /sup 3/He, and ..cap alpha..) following neutron interactions with /sup 12/C. Extensive comparisons with a variety of experimental data are given. There is generally overall good agreement (<10% differences) of results from SCINFUL calculations with measured detector responses, i.e., N(E/sub r/) vs E/sub r/more » where E/sub r/ is the response pulse height, reproduce measured detector responses with an accuracy which, at least partly, depends upon how well the experimental configuration is known. For E/sub n/ < 16 MeV and for E/sub r/ > 15% of the maximum pulse height response, calculated spectra are within +-5% of experiment on the average. For E/sub n/ up to 50 MeV similar good agreement is obtained with experiment for E/sub r/ > 30% of maximum response. For E/sub n/ up to 75 MeV the calculated shape of the response agrees with measurements, but the calculations underpredicts the measured response by up to 30%. 65 refs., 64 figs., 3 tabs.« less

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain.

PubMed

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn.

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain

PubMed Central

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn. PMID:26771517

A macro-micro robot for precise force applications

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.; Wang, Yulun

1993-01-01

This paper describes an 8 degree-of-freedom macro-micro robot capable of performing tasks which require accurate force control. Applications such as polishing, finishing, grinding, deburring, and cleaning are a few examples of tasks which need this capability. Currently these tasks are either performed manually or with dedicated machinery because of the lack of a flexible and cost effective tool, such as a programmable force-controlled robot. The basic design and control of the macro-micro robot is described in this paper. A modular high-performance multiprocessor control system was designed to provide sufficient compute power for executing advanced control methods. An 8 degree of freedom macro-micro mechanism was constructed to enable accurate tip forces. Control algorithms based on the impedance control method were derived, coded, and load balanced for maximum execution speed on the multiprocessor system.

Two-phase mixed media dielectric with macro dielectric beads for enhancing resistivity and breakdown strength

DOEpatents

Falabella, Steven; Meyer, Glenn A; Tang, Vincent; Guethlein, Gary

2014-06-10

A two-phase mixed media insulator having a dielectric fluid filling the interstices between macro-sized dielectric beads packed into a confined volume, so that the packed dielectric beads inhibit electro-hydrodynamically driven current flows of the dielectric liquid and thereby increase the resistivity and breakdown strength of the two-phase insulator over the dielectric liquid alone. In addition, an electrical apparatus incorporates the two-phase mixed media insulator to insulate between electrical components of different electrical potentials. And a method of electrically insulating between electrical components of different electrical potentials fills a confined volume between the electrical components with the two-phase dielectric composite, so that the macro dielectric beads are packed in the confined volume and interstices formed between the macro dielectric beads are filled with the dielectric liquid.

Three-dimensional macro-structures of two-dimensional nanomaterials.

PubMed

Shehzad, Khurram; Xu, Yang; Gao, Chao; Duan, Xiangfeng

2016-10-21

If two-dimensional (2D) nanomaterials are ever to be utilized as components of practical, macroscopic devices on a large scale, there is a complementary need to controllably assemble these 2D building blocks into more sophisticated and hierarchical three-dimensional (3D) architectures. Such a capability is key to design and build complex, functional devices with tailored properties. This review provides a comprehensive overview of the various experimental strategies currently used to fabricate the 3D macro-structures of 2D nanomaterials. Additionally, various approaches for the decoration of the 3D macro-structures with organic molecules, polymers, and inorganic materials are reviewed. Finally, we discuss the applications of 3D macro-structures, especially in the areas of energy, environment, sensing, and electronics, and describe the existing challenges and the outlook for this fast emerging field.

ETA-MACRO: A user's guide

NASA Astrophysics Data System (ADS)

Manne, A. S.

1981-02-01

The ETA-MACRO model is designed to estimate the extent of two way linkage between the energy sector and the balance of the economy. It represents a merger between ETA (a process analysis for energy technology assessment) together with a macroeconomic growth model providing for substitution between capital, labor, and energy inputs. The ETA-MACRO allows explicitly for: (1) energy economy interactions; (2) cost effective conservation; (3) interfuel substitution, and (4) new supply technologies, each with its own difficulties and uncertainties on dates and rates of introduction. This user's guide includes an overview of the model, an illustrative application to long term US energy projections, and technical descriptions of the macro and ETA submodels. It also includes an analysis of how market penetration rates may be related to the profitability of new technologies. Finally, the appendices provide a detailed guide to the computer implementation.

Identification of critical residues in Hepatitis E virus macro domain involved in its interaction with viral methyltransferase and ORF3 proteins

PubMed Central

Anang, Saumya; Subramani, Chandru; Nair, Vidya P.; Kaul, Sheetal; Kaushik, Nidhi; Sharma, Chandresh; Tiwari, Ashutosh; Ranjith-Kumar, CT; Surjit, Milan

2016-01-01

Hepatitis E virus (HEV) is a major cause of hepatitis in normal and organ transplant individuals. HEV open reading frame-1 encodes a polypeptide comprising of the viral nonstructural proteins as well as domains of unknown function such as the macro domain (X-domain), V, DUF3729 and Y. The macro domain proteins are ubiquitously present from prokaryotes to human and in many positive-strand RNA viruses, playing important roles in multiple cellular processes. Towards understanding the function of the HEV macro domain, we characterized its interaction partners among other HEV encoded proteins. Here, we report that the HEV X-domain directly interacts with the viral methyltransferase and the ORF3 proteins. ORF3 association with the X-domain was mediated through two independent motifs, located within its N-terminal 35aa (amino acids) and C-terminal 63-123aa. Methyltransferase interaction domain was mapped to N-terminal 30-90aa. The X-domain interacted with both ORF3 and methyltransferase through its C-terminal region, involving 66th,67th isoleucine and 101st,102nd leucine, conserved across HEV genotypes. Furthermore, ORF3 and methyltransferase competed with each other for associating with the X-domain. These findings provide molecular understanding of the interaction between the HEV macro domain, methyltransferase and ORF3, suggesting an important role of the macro domain in the life cycle of HEV. PMID:27113483

MacroBac: New Technologies for Robust and Efficient Large-Scale Production of Recombinant Multiprotein Complexes.

PubMed

Gradia, Scott D; Ishida, Justin P; Tsai, Miaw-Sheue; Jeans, Chris; Tainer, John A; Fuss, Jill O

2017-01-01

Recombinant expression of large, multiprotein complexes is essential and often rate limiting for determining structural, biophysical, and biochemical properties of DNA repair, replication, transcription, and other key cellular processes. Baculovirus-infected insect cell expression systems are especially well suited for producing large, human proteins recombinantly, and multigene baculovirus systems have facilitated studies of multiprotein complexes. In this chapter, we describe a multigene baculovirus system called MacroBac that uses a Biobricks-type assembly method based on restriction and ligation (Series 11) or ligation-independent cloning (Series 438). MacroBac cloning and assembly is efficient and equally well suited for either single subcloning reactions or high-throughput cloning using 96-well plates and liquid handling robotics. MacroBac vectors are polypromoter with each gene flanked by a strong polyhedrin promoter and an SV40 poly(A) termination signal that minimize gene order expression level effects seen in many polycistronic assemblies. Large assemblies are robustly achievable, and we have successfully assembled as many as 10 genes into a single MacroBac vector. Importantly, we have observed significant increases in expression levels and quality of large, multiprotein complexes using a single, multigene, polypromoter virus rather than coinfection with multiple, single-gene viruses. Given the importance of characterizing functional complexes, we believe that MacroBac provides a critical enabling technology that may change the way that structural, biophysical, and biochemical research is done. © 2017 Elsevier Inc. All rights reserved.

Calibrating and training of neutron based NSA techniques with less SNM standards

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

Geist, William H; Swinhoe, Martyn T; Bracken, David S

2010-01-01

Accessing special nuclear material (SNM) standards for the calibration of and training on nondestructive assay (NDA) instruments has become increasingly difficult in light of enhanced safeguards and security regulations. Limited or nonexistent access to SNM has affected neutron based NDA techniques more than gamma ray techniques because the effects of multiplication require a range of masses to accurately measure the detector response. Neutron based NDA techniques can also be greatly affected by the matrix and impurity characteristics of the item. The safeguards community has been developing techniques for calibrating instrumentation and training personnel with dwindling numbers of SNM standards. Montemore » Carlo methods have become increasingly important for design and calibration of instrumentation. Monte Carlo techniques have the ability to accurately predict the detector response for passive techniques. The Monte Carlo results are usually benchmarked to neutron source measurements such as californium. For active techniques, the modeling becomes more difficult because of the interaction of the interrogation source with the detector and nuclear material; and the results cannot be simply benchmarked with neutron sources. A Monte Carlo calculated calibration curve for a training course in Indonesia of material test reactor (MTR) fuel elements assayed with an active well coincidence counter (AWCC) will be presented as an example. Performing training activities with reduced amounts of nuclear material makes it difficult to demonstrate how the multiplication and matrix properties of the item affects the detector response and limits the knowledge that can be obtained with hands-on training. A neutron pulse simulator (NPS) has been developed that can produce a pulse stream representative of a real pulse stream output from a detector measuring SNM. The NPS has been used by the International Atomic Energy Agency (IAEA) for detector testing and training applications at the Agency due to the lack of appropriate SNM standards. This paper will address the effect of reduced access to SNM for calibration and training of neutron NDA applications along with the advantages and disadvantages of some solutions that do not use standards, such as the Monte Carlo techniques and the NPS.« less

Monte Carlo calculation of the sensitivity of a commercial dose calibrator to gamma and beta radiation.

PubMed

Laedermann, Jean-Pascal; Valley, Jean-François; Bulling, Shelley; Bochud, François O

2004-06-01

The detection process used in a commercial dose calibrator was modeled using the GEANT 3 Monte Carlo code. Dose calibrator efficiency for gamma and beta emitters, and the response to monoenergetic photons and electrons was calculated. The model shows that beta emitters below 2.5 MeV deposit energy indirectly in the detector through bremsstrahlung produced in the chamber wall or in the source itself. Higher energy beta emitters (E > 2.5 MeV) deposit energy directly in the chamber sensitive volume, and dose calibrator sensitivity increases abruptly for these radionuclides. The Monte Carlo calculations were compared with gamma and beta emitter measurements. The calculations show that the variation in dose calibrator efficiency with measuring conditions (source volume, container diameter, container wall thickness and material, position of the source within the calibrator) is relatively small and can be considered insignificant for routine measurement applications. However, dose calibrator efficiency depends strongly on the inner-wall thickness of the detector.

A Monte Carlo Simulation Investigating the Validity and Reliability of Ability Estimation in Item Response Theory with Speeded Computer Adaptive Tests

ERIC Educational Resources Information Center

Schmitt, T. A.; Sass, D. A.; Sullivan, J. R.; Walker, C. M.

2010-01-01

Imposed time limits on computer adaptive tests (CATs) can result in examinees having difficulty completing all items, thus compromising the validity and reliability of ability estimates. In this study, the effects of speededness were explored in a simulated CAT environment by varying examinee response patterns to end-of-test items. Expectedly,…

Adjusting the Adjusted X[superscript 2]/df Ratio Statistic for Dichotomous Item Response Theory Analyses: Does the Model Fit?

ERIC Educational Resources Information Center

Tay, Louis; Drasgow, Fritz

2012-01-01

Two Monte Carlo simulation studies investigated the effectiveness of the mean adjusted X[superscript 2]/df statistic proposed by Drasgow and colleagues and, because of problems with the method, a new approach for assessing the goodness of fit of an item response theory model was developed. It has been previously recommended that mean adjusted…

Monte Carlo calculated microdosimetric spread for cell nucleus-sized targets exposed to brachytherapy 125I and 192Ir sources and 60Co cell irradiation.

PubMed

Villegas, Fernanda; Tilly, Nina; Ahnesjö, Anders

2013-09-07

The stochastic nature of ionizing radiation interactions causes a microdosimetric spread in energy depositions for cell or cell nucleus-sized volumes. The magnitude of the spread may be a confounding factor in dose response analysis. The aim of this work is to give values for the microdosimetric spread for a range of doses imparted by (125)I and (192)Ir brachytherapy radionuclides, and for a (60)Co source. An upgraded version of the Monte Carlo code PENELOPE was used to obtain frequency distributions of specific energy for each of these radiation qualities and for four different cell nucleus-sized volumes. The results demonstrate that the magnitude of the microdosimetric spread increases when the target size decreases or when the energy of the radiation quality is reduced. Frequency distributions calculated according to the formalism of Kellerer and Chmelevsky using full convolution of the Monte Carlo calculated single track frequency distributions confirm that at doses exceeding 0.08 Gy for (125)I, 0.1 Gy for (192)Ir, and 0.2 Gy for (60)Co, the resulting distribution can be accurately approximated with a normal distribution. A parameterization of the width of the distribution as a function of dose and target volume of interest is presented as a convenient form for the use in response modelling or similar contexts.

Identification of Thyroid Receptor Ant/Agonists in Water Sources Using Mass Balance Analysis and Monte Carlo Simulation

PubMed Central

Shi, Wei; Wei, Si; Hu, Xin-xin; Hu, Guan-jiu; Chen, Cu-lan; Wang, Xin-ru; Giesy, John P.; Yu, Hong-xia

2013-01-01

Some synthetic chemicals, which have been shown to disrupt thyroid hormone (TH) function, have been detected in surface waters and people have the potential to be exposed through water-drinking. Here, the presence of thyroid-active chemicals and their toxic potential in drinking water sources in Yangtze River Delta were investigated by use of instrumental analysis combined with cell-based reporter gene assay. A novel approach was developed to use Monte Carlo simulation, for evaluation of the potential risks of measured concentrations of TH agonists and antagonists and to determine the major contributors to observed thyroid receptor (TR) antagonist potency. None of the extracts exhibited TR agonist potency, while 12 of 14 water samples exhibited TR antagonistic potency. The most probable observed antagonist equivalents ranged from 1.4 to 5.6 µg di-n-butyl phthalate (DNBP)/L, which posed potential risk in water sources. Based on Monte Carlo simulation related mass balance analysis, DNBP accounted for 64.4% for the entire observed antagonist toxic unit in water sources, while diisobutyl phthalate (DIBP), di-n-octyl phthalate (DNOP) and di-2-ethylhexyl phthalate (DEHP) also contributed. The most probable observed equivalent and most probable relative potency (REP) derived from Monte Carlo simulation is useful for potency comparison and responsible chemicals screening. PMID:24204563

In vitro LED and laser light photoinactivation of Propionibacterium acnes

NASA Astrophysics Data System (ADS)

Tuchina, Elena S.; Tuchin, Valery V.

2008-06-01

Acne is a genetic, hormonal disease characterized by overproduction of oil by the sebaceous glands, plugging of the sebaceous glands to form micro- and macro- comedons and, finally, action of skin bacteria on oil trapped underneath the skin to red inflammatory cystic lesions. It was shown, that Propionibacterium acnes, the bacteria responsible for acne, was rather subjected to action of red and infrared radiation. The effect of the given radiation amplified at this bacteria by various solutions of photosensitizes.

Macro-level determinants of young people's subjective health and health inequalities: a multilevel analysis in 27 welfare states.

PubMed

Rathmann, Katharina; Ottova, Veronika; Hurrelmann, Klaus; de Looze, Margarethe; Levin, Kate; Molcho, Michal; Elgar, Frank; Gabhainn, Saoirse Nic; van Dijk, Jitse P; Richter, Matthias

2015-04-01

Cross-national studies have rarely focused on young people. The aim of this study is to investigate whether macro-level determinants are associated with health and socioeconomic inequalities in young people's health. Data were collected from the Health Behaviour in School-aged Children (HBSC) study in 2006, which included 11- to 15-year old adolescents from 27 European and North American countries (n=134,632). This study includes national income, health expenditure, income inequality, and welfare regime dummy-variables as macro-level determinants, using hierarchical regression modelling. Psychosomatic health complaints and socioeconomic inequalities in psychosomatic health complaints. Adolescents in countries with higher income inequality and with liberal welfare tradition were associated with more health complaints and a stronger relationship between socioeconomic status and macro-level determinants compared to adolescents from countries with lower income inequality or the Social Democratic regime. National income and health expenditure were not related to health complaints. Countries with higher national income, public health expenditure and income inequality showed stronger associations between socioeconomic status and psychosomatic health complaints. Results showed that macro-level characteristics are relevant determinants of health and health inequalities in adolescence. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Controllable growth of polyaniline nanowire arrays on hierarchical macro/mesoporous graphene foams for high-performance flexible supercapacitors

NASA Astrophysics Data System (ADS)

Yu, Pingping; Zhao, Xin; Li, Yingzhi; Zhang, Qinghua

2017-01-01

Free-standing hierarchical macro/mesoporous flexible graphene foam have been constructed by rational intergration ofwell dispersed graphene oxide sheets and amino-modified polystyrene (PS) spheres through a facile ;templating and embossing; technique. The three dimensional (3D) macro/mesoporous flexible graphene foam not only inherits the uniform porous structures of graphene foam, but also contains hierarchical macro/mesopores on the struts by sacrificing PS spheres and the activation of KOH, which could providing rapid pathways for ionic and electronic transport to high specific capacitance. Vertically polyaniline (PANI) nanowire arrays are then uniformly deposited onto the hierarchical macro/mesoporous graphene foam(fRGO-F/PANI) by a simple in situ polymerization, which show a high specific capacitance of 939 F g-1. Thanks to the synergistic function of 3D bicontinuous hierarchical porous structure of graphene foam and effective immobilization of PANI nanowires on the struts, the assembled symmetric supercapctior with fRGO-F/PANI as electrodes exhibits a maximum energy density and power density of 20.9 Wh kg-1 and 103.2 kW kg-1, respectively. Moreover, it also displays an excellent cyclic stability with a 88.7% retention after 5000 cycles.

Automated a complex computer aided design concept generated using macros programming

NASA Astrophysics Data System (ADS)

Rizal Ramly, Mohammad; Asrokin, Azharrudin; Abd Rahman, Safura; Zulkifly, Nurul Ain Md

2013-12-01

Changing a complex Computer Aided design profile such as car and aircraft surfaces has always been difficult and challenging. The capability of CAD software such as AutoCAD and CATIA show that a simple configuration of a CAD design can be easily modified without hassle, but it is not the case with complex design configuration. Design changes help users to test and explore various configurations of the design concept before the production of a model. The purpose of this study is to look into macros programming as parametric method of the commercial aircraft design. Macros programming is a method where the configurations of the design are done by recording a script of commands, editing the data value and adding a certain new command line to create an element of parametric design. The steps and the procedure to create a macro programming are discussed, besides looking into some difficulties during the process of creation and advantage of its usage. Generally, the advantages of macros programming as a method of parametric design are; allowing flexibility for design exploration, increasing the usability of the design solution, allowing proper contained by the model while restricting others and real time feedback changes.

MACRO: a combined microchip-PCR and microarray system for high-throughput monitoring of genetically modified organisms.

PubMed

Shao, Ning; Jiang, Shi-Meng; Zhang, Miao; Wang, Jing; Guo, Shu-Juan; Li, Yang; Jiang, He-Wei; Liu, Cheng-Xi; Zhang, Da-Bing; Yang, Li-Tao; Tao, Sheng-Ce

2014-01-21

The monitoring of genetically modified organisms (GMOs) is a primary step of GMO regulation. However, there is presently a lack of effective and high-throughput methodologies for specifically and sensitively monitoring most of the commercialized GMOs. Herein, we developed a multiplex amplification on a chip with readout on an oligo microarray (MACRO) system specifically for convenient GMO monitoring. This system is composed of a microchip for multiplex amplification and an oligo microarray for the readout of multiple amplicons, containing a total of 91 targets (18 universal elements, 20 exogenous genes, 45 events, and 8 endogenous reference genes) that covers 97.1% of all GM events that have been commercialized up to 2012. We demonstrate that the specificity of MACRO is ~100%, with a limit of detection (LOD) that is suitable for real-world applications. Moreover, the results obtained of simulated complex samples and blind samples with MACRO were 100% consistent with expectations and the results of independently performed real-time PCRs, respectively. Thus, we believe MACRO is the first system that can be applied for effectively monitoring the majority of the commercialized GMOs in a single test.

Shaping electromagnetic waves using software-automatically-designed metasurfaces.

PubMed

Zhang, Qian; Wan, Xiang; Liu, Shuo; Yuan Yin, Jia; Zhang, Lei; Jun Cui, Tie

2017-06-15

We present a fully digital procedure of designing reflective coding metasurfaces to shape reflected electromagnetic waves. The design procedure is completely automatic, controlled by a personal computer. In details, the macro coding units of metasurface are automatically divided into several types (e.g. two types for 1-bit coding, four types for 2-bit coding, etc.), and each type of the macro coding units is formed by discretely random arrangement of micro coding units. By combining an optimization algorithm and commercial electromagnetic software, the digital patterns of the macro coding units are optimized to possess constant phase difference for the reflected waves. The apertures of the designed reflective metasurfaces are formed by arranging the macro coding units with certain coding sequence. To experimentally verify the performance, a coding metasurface is fabricated by automatically designing two digital 1-bit unit cells, which are arranged in array to constitute a periodic coding metasurface to generate the required four-beam radiations with specific directions. Two complicated functional metasurfaces with circularly- and elliptically-shaped radiation beams are realized by automatically designing 4-bit macro coding units, showing excellent performance of the automatic designs by software. The proposed method provides a smart tool to realize various functional devices and systems automatically.

The permeability of fractured rocks in pressurised volcanic and geothermal systems.

PubMed

Lamur, A; Kendrick, J E; Eggertsson, G H; Wall, R J; Ashworth, J D; Lavallée, Y

2017-07-21

The connectivity of rocks' porous structure and the presence of fractures influence the transfer of fluids in the Earth's crust. Here, we employed laboratory experiments to measure the influence of macro-fractures and effective pressure on the permeability of volcanic rocks with a wide range of initial porosities (1-41 vol. %) comprised of both vesicles and micro-cracks. We used a hand-held permeameter and hydrostatic cell to measure the permeability of intact rock cores at effective pressures up to 30 MPa; we then induced a macro-fracture to each sample using Brazilian tensile tests and measured the permeability of these macro-fractured rocks again. We show that intact rock permeability increases non-linearly with increasing porosity and decreases with increasing effective pressure due to compactional closure of micro-fractures. Imparting a macro-fracture both increases the permeability of rocks and their sensitivity to effective pressure. The magnitude of permeability increase induced by the macro-fracture is more significant for dense rocks. We finally provide a general equation to estimate the permeability of intact and fractured rocks, forming a basis to constrain fluid flow in volcanic and geothermal systems.

Motor unit size estimation: confrontation of surface EMG with macro EMG.

PubMed

Roeleveld, K; Stegeman, D F; Falck, B; Stålberg, E V

1997-06-01

Surface EMG (SEMG) is little used for diagnostic purposes in clinical neurophysiology, mainly because it provides little direct information on individual motor units (MUs). One of the techniques to estimate the MU size is intra-muscular Macro EMG. The present study compares SEMG with Macro EMG. Fifty-eight channel SEMG was recorded simultaneously with Macro EMG. Individual MUPs were obtained by single fiber triggered averaging. All recordings were made from the biceps brachii of healthy subjects during voluntary contraction at low force. High positive correlations were found between all Macro and Surface motor unit potential (MUP) parameters: area, peak-to-peak amplitude, negative peak amplitude and positive peak amplitude. The MUPs recorded with SEMG were dependent on the distance between the MU and the skin surface. Normalizing the SEMG parameters for MU location did not improve the correlation coefficient between the parameters of both techniques. The two measurement techniques had almost the same relative range in MUP parameters in any individual subject compared to the others, especially after normalizing the surface MUP parameters for MU location. MUPs recorded with this type of SEMG provide useful information about the MU size.

Race and Space in the 1990s: Changes in the Geographic Scale of Racial Residential Segregation, 1990-2000

PubMed Central

Reardon, Sean F.; Farrell, Chad R.; Matthews, Stephen A.; O'Sullivan, David; Bischoff, Kendra; Firebaugh, Glenn

2014-01-01

We use newly developed methods of measuring spatial segregation across a range of spatial scales to assess changes in racial residential segregation patterns in the 100 largest U.S. metropolitan areas from 1990 to 2000. Our results point to three notable trends in segregation from 1990 to 2000: 1) Hispanic-white and Asian-white segregation levels increased at both micro- and macro-scales; 2) black-white segregation declined at a micro-scale, but was unchanged at a macro-scale; and 3) for all three racial groups and for almost all metropolitan areas, macro-scale segregation accounted for more of the total metropolitan area segregation in 2000 than in 1990. Our examination of the variation in these trends among the metropolitan areas suggests that Hispanic-white and Asian-white segregation changes have been driven largely by increases in macro-scale segregation resulting from the rapid growth of the Hispanic and Asian populations in central cities. The changes in black-white segregation, in contrast, appear to be driven by the continuation of a 30-year trend in declining micro-segregation, coupled with persistent and largely stable patterns of macro-segregation. PMID:19569292

Macro scale models for freight railroad terminals.

DOT National Transportation Integrated Search

2016-03-02

The project has developed a yard capacity model for macro-level analysis. The study considers the detailed sequence and scheduling in classification yards and their impacts on yard capacities simulate typical freight railroad terminals, and statistic...

Using complexity theory to analyse the organisational response to resurgent tuberculosis across London.

PubMed

Trenholm, Susan; Ferlie, Ewan

2013-09-01

We employ complexity theory to analyse the English National Health Service (NHS)'s organisational response to resurgent tuberculosis across London. Tennison (2002) suggests that complexity theory could fruitfully explore a healthcare system's response to this complex and emergent phenomenon: we explore this claim here. We also bring in established New Public Management principles to enhance our empirical analysis, which is based on data collected between late 2009 and mid-2011. We find that the operation of complexity theory based features, especially self-organisation, are significantly impacted by the macro context of a New Public Management-based regime which values control, measurement and risk management more than innovation, flexibility and lateral system building. We finally explore limitations and suggest perspectives for further research. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fertility transitions and schooling: from micro- to macro-level associations.

PubMed

Eloundou-Enyegue, Parfait M; Giroux, Sarah C

2012-11-01

Research on the schooling implications of fertility transitions often faces an aggregation problem: despite policy interest in macro-level outcomes, empirical studies usually focus on the micro-level effects of sibsize on schooling. This article proposes an aggregation framework for moving from micro- to macro-level associations between fertility and schooling. The proposed framework is an improvement over previous aggregation methods in that it considers concurrent changes in the effects of sibsize, socioeconomic context, and family structure. The framework is illustrated with data from six sub-Saharan countries. Possible extensions are discussed.

Fast and accurate modeling of stray light in optical systems

NASA Astrophysics Data System (ADS)

Perrin, Jean-Claude

2017-11-01

The first problem to be solved in most optical designs with respect to stray light is that of internal reflections on the several surfaces of individual lenses and mirrors, and on the detector itself. The level of stray light ratio can be considerably reduced by taking into account the stray light during the optimization to determine solutions in which the irradiance due to these ghosts is kept to the minimum possible value. Unhappily, the routines available in most optical design software's, for example CODE V, do not permit all alone to make exact quantitative calculations of the stray light due to these ghosts. Therefore, the engineer in charge of the optical design is confronted to the problem of using two different software's, one for the design and optimization, for example CODE V, one for stray light analysis, for example ASAP. This makes a complete optimization very complex . Nevertheless, using special techniques and combinations of the routines available in CODE V, it is possible to have at its disposal a software macro tool to do such an analysis quickly and accurately, including Monte-Carlo ray tracing, or taking into account diffraction effects. This analysis can be done in a few minutes, to be compared to hours with other software's.

Four applications of permutation methods to testing a single-mediator model.

PubMed

Taylor, Aaron B; MacKinnon, David P

2012-09-01

Four applications of permutation tests to the single-mediator model are described and evaluated in this study. Permutation tests work by rearranging data in many possible ways in order to estimate the sampling distribution for the test statistic. The four applications to mediation evaluated here are the permutation test of ab, the permutation joint significance test, and the noniterative and iterative permutation confidence intervals for ab. A Monte Carlo simulation study was used to compare these four tests with the four best available tests for mediation found in previous research: the joint significance test, the distribution of the product test, and the percentile and bias-corrected bootstrap tests. We compared the different methods on Type I error, power, and confidence interval coverage. The noniterative permutation confidence interval for ab was the best performer among the new methods. It successfully controlled Type I error, had power nearly as good as the most powerful existing methods, and had better coverage than any existing method. The iterative permutation confidence interval for ab had lower power than do some existing methods, but it performed better than any other method in terms of coverage. The permutation confidence interval methods are recommended when estimating a confidence interval is a primary concern. SPSS and SAS macros that estimate these confidence intervals are provided.

An initial event in the insect innate immune response: structural and biological studies of interactions between β-1,3-glucan and the N-terminal domain of β-1,3-glucan recognition protein.

PubMed

Dai, Huaien; Hiromasa, Yasuaki; Takahashi, Daisuke; VanderVelde, David; Fabrick, Jeffrey A; Kanost, Michael R; Krishnamoorthi, Ramaswamy

2013-01-08

In response to invading microorganisms, insect β-1,3-glucan recognition protein (βGRP), a soluble receptor in the hemolymph, binds to the surfaces of bacteria and fungi and activates serine protease cascades that promote destruction of pathogens by means of melanization or expression of antimicrobial peptides. Here we report on the nuclear magnetic resonance (NMR) solution structure of the N-terminal domain of βGRP (N-βGRP) from Indian meal moth (Plodia interpunctella), which is sufficient to activate the prophenoloxidase (proPO) pathway resulting in melanin formation. NMR and isothermal calorimetric titrations of N-βGRP with laminarihexaose, a glucose hexamer containing β-1,3 links, suggest a weak binding of the ligand. However, addition of laminarin, a glucose polysaccharide (~6 kDa) containing β-1,3 and β-1,6 links that activates the proPO pathway, to N-βGRP results in the loss of NMR cross-peaks from the backbone (15)N-(1)H groups of the protein, suggesting the formation of a large complex. Analytical ultracentrifugation (AUC) studies of formation of the N-βGRP-laminarin complex show that ligand binding induces self-association of the protein-carbohydrate complex into a macro structure, likely containing six protein and three laminarin molecules (~102 kDa). The macro complex is quite stable, as it does not undergo dissociation upon dilution to submicromolar concentrations. The structural model thus derived from this study for the N-βGRP-laminarin complex in solution differs from the one in which a single N-βGRP molecule has been proposed to bind to a triple-helical form of laminarin on the basis of an X-ray crystallographic structure of the N-βGRP-laminarihexaose complex [Kanagawa, M., Satoh, T., Ikeda, A., Adachi, Y., Ohno, N., and Yamaguchi, Y. (2011) J. Biol. Chem. 286, 29158-29165]. AUC studies and phenoloxidase activation measurements conducted with the designed mutants of N-βGRP indicate that electrostatic interactions involving Asp45, Arg54, and Asp68 between the ligand-bound protein molecules contribute in part to the stability of the N-βGRP-laminarin macro complex and that a decreased stability is accompanied by a reduced level of activation of the proPO pathway. An increased level of β-1,6 branching in laminarin also results in destabilization of the macro complex. These novel findings suggest that ligand-induced self-association of the βGRP-β-1,3-glucan complex may form a platform on a microbial surface for recruitment of downstream proteases, as a means of amplification of the initial signal of pathogen recognition for the activation of the proPO pathway.

Does the Effect of Micro-Environmental Factors on a Street's Appeal for Adults' Bicycle Transport Vary across Different Macro-Environments? An Experimental Study.

PubMed

Mertens, Lieze; Van Cauwenberg, Jelle; Ghekiere, Ariane; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien

2015-01-01

Characteristics of the physical environment can be classified into two broad categories: macro- ("raw" urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street's appeal for adults' bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street). In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data. Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path. Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street's appeal for bicycle transport. The controlled environment simulations in the experimental choice task have the potential to inform real life environmental interventions and suggest that micro-environmental changes can have similar results in different macro-environments.

Automated toxicological screening reports of modified Agilent MSD Chemstation combined with Microsoft Visual Basic application programs.

PubMed

Choe, Sanggil; Kim, Suncheun; Choi, Hyeyoung; Choi, Hwakyoung; Chung, Heesun; Hwang, Bangyeon

2010-06-15

Agilent GC-MS MSD Chemstation offers automated library search report for toxicological screening using total ion chromatogram (TIC) and mass spectroscopy in normal mode. Numerous peaks appear in the chromatogram of biological specimen such as blood or urine and often large migrating peaks obscure small target peaks, in addition, any target peaks of low abundance regularly give wrong library search result or low matching score. As a result, retention time and mass spectrum of all the peaks in the chromatogram have to be checked to see if they are relevant. These repeated actions are very tedious and time-consuming to toxicologists. MSD Chemstation software operates using a number of macro files which give commands and instructions on how to work on and extract data from the chromatogram and spectroscopy. These macro files are developed by the own compiler of the software. All the original macro files can be modified and new macro files can be added to the original software by users. To get more accurate results with more convenient method and to save time for data analysis, we developed new macro files for reports generation and inserted new menus in the Enhanced Data Analysis program. Toxicological screening reports generated by these new macro files are in text mode or graphic mode and these reports can be generated with three different automated subtraction options. Text reports have Brief mode and Full mode and graphic reports have the option with or without mass spectrum mode. Matched mass spectrum and matching score for detected compounds are printed in reports by modified library searching modules. We have also developed an independent application program named DrugMan. This program manages drug groups, lists and parameters that are in use in MSD Chemstation. The incorporation of DrugMan with modified macro modules provides a powerful tool for toxicological screening and save a lot of valuable time on toxicological work. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Light transport feature for SCINFUL.

PubMed

Etaati, G R; Ghal-Eh, N

2008-03-01

An extended version of the scintillator response function prediction code SCINFUL has been developed by incorporating PHOTRACK, a Monte Carlo light transport code. Comparisons of calculated and experimental results for organic scintillators exposed to neutrons show that the extended code improves the predictive capability of SCINFUL.

Multicategorical Spline Model for Item Response Theory.

ERIC Educational Resources Information Center

Abrahamowicz, Michal; Ramsay, James O.

1992-01-01

A nonparametric multicategorical model for multiple-choice data is proposed as an extension of the binary spline model of J. O. Ramsay and M. Abrahamowicz (1989). Results of two Monte Carlo studies illustrate the model, which approximates probability functions by rational splines. (SLD)

Breast Cancer Risk Assessment SAS Macro (Gail Model)

Cancer.gov

A SAS macro (commonly referred to as the Gail Model) that projects absolute risk of invasive breast cancer according to NCI’s Breast Cancer Risk Assessment Tool (BCRAT) algorithm for specified race/ethnic groups and age intervals.

Some methodological issues in the longitudinal analysis of demographic data.

PubMed

Krishinan, P

1982-12-01

Most demographic data are macro (or aggregate) in nature. Some relevant methodological issues are presented here in a time series study using aggregate data. The micro-macro distinction is relative. Time enters into the micro and macro variables in different ways. A simple micro model of rural-urban migration is given. Method 1 is to assume homogeneity in behavior. Method 2 is a Bayesian estimation. A discusssion of the results follows. Time series models of aggregate data are given. The nature of the model--predictive or explanatory--must be decided on. Explanatory models in longitudinal studies have been developed. Ways to go to the micro level from the macro are discussed. The aggregation-disaggregation problem in demography is not similar to that in econometrics. To understand small populations, separate micro level data have to be collected and analyzed and appropriate models developed. Both types of models have their uses.

Exploring the links between macro-level contextual factors and their influence on nursing workforce composition.

PubMed

Squires, Allison; Beltrán-Sánchez, Hiram

2011-11-01

Research that links macro-level socioeconomic development variables to health care human resources workforce composition is scarce at best. The purpose of this study was to explore the links between nonnursing factors and nursing workforce composition through a secondary, descriptive analysis of year 2000, publicly available national nursing human resources data from Mexico. Building on previous research, the authors conducted multiple robust regression analysis by federal typing of nursing human resources from 31 Mexican states against macro-level socioeconomic development variables. Average education in a state was significantly associated in predicting all types of formally educated nurses in Mexico. Other results suggest that macro-level indicators have a different association with each type of nurse. Context may play a greater role in determining nursing workforce composition than previously thought. Further studies may help to explain differences both within and between countries.

Exploring the Links Between Macro-Level Contextual Factors and Their Influence on Nursing Workforce Composition

PubMed Central

Squires, Allison; Beltrán-Sánchez, Hiram

2012-01-01

Research that links macro-level socioeconomic development variables to healthcare human resources workforce composition is scarce at best. The purpose of this study was to explore the links between non-nursing factors and nursing workforce composition through a secondary, descriptive analysis of year 2000, publicly available national nursing human resources data from Mexico. Building on previous research, the authors conducted multiple robust regression analysis by federal typing of nursing human resources from 31 Mexican states against macro-level socioeconomic development variables. Average education in a state was significantly associated in predicting all types of formally educated nurses in Mexico. Other results suggest that macro level indicators have a different association with each type of nurse. Context may play a greater role in determining nursing workforce composition than previously thought. Further studies may help to explain differences both within and between countries. PMID:22513839

An Introduction to Macro- Level Spatial Nonstationarity: a Geographically Weighted Regression Analysis of Diabetes and Poverty

PubMed Central

Siordia, Carlos; Saenz, Joseph; Tom, Sarah E.

2014-01-01

Type II diabetes is a growing health problem in the United States. Understanding geographic variation in diabetes prevalence will inform where resources for management and prevention should be allocated. Investigations of the correlates of diabetes prevalence have largely ignored how spatial nonstationarity might play a role in the macro-level distribution of diabetes. This paper introduces the reader to the concept of spatial nonstationarity—variance in statistical relationships as a function of geographical location. Since spatial nonstationarity means different predictors can have varying effects on model outcomes, we make use of a geographically weighed regression to calculate correlates of diabetes as a function of geographic location. By doing so, we demonstrate an exploratory example in which the diabetes-poverty macro-level statistical relationship varies as a function of location. In particular, we provide evidence that when predicting macro-level diabetes prevalence, poverty is not always positively associated with diabetes PMID:25414731

Political democracy, economic liberalization, and macro-sociological models of intergenerational mobility.

PubMed

Gugushvili, Alexi

2017-08-01

Building on the previously investigated macro-sociological models which analyze the consequences of economic development, income inequality, and international migration on social mobility, this article studies the specific contextual covariates of intergenerational reproduction of occupational status in post-communist societies. It is theorized that social mobility is higher in societies with democratic political regimes and less liberalized economies. The outlined hypotheses are tested by using micro- and macro-level datasets for 21 post-communist societies which are fitted into multilevel mixed-effects linear regressions. The derived findings suggest that factors specific to transition societies, conventional macro-level variables, and the legacy of the Soviet Union explain variation in intergenerational social mobility, but the results vary depending which birth cohorts survey participants belong to and whether or not they stem from advantaged or disadvantaged social origins. These findings are robust to various alternative data, sample, and method specifications. Copyright © 2017 Elsevier Inc. All rights reserved.

Macro-/Micro-Controlled 3D Lithium-Ion Batteries via Additive Manufacturing and Electric Field Processing.

PubMed

Li, Jie; Liang, Xinhua; Liou, Frank; Park, Jonghyun

2018-01-30

This paper presents a new concept for making battery electrodes that can simultaneously control macro-/micro-structures and help address current energy storage technology gaps and future energy storage requirements. Modern batteries are fabricated in the form of laminated structures that are composed of randomly mixed constituent materials. This randomness in conventional methods can provide a possibility of developing new breakthrough processing techniques to build well-organized structures that can improve battery performance. In the proposed processing, an electric field (EF) controls the microstructures of manganese-based electrodes, while additive manufacturing controls macro-3D structures and the integration of both scales. The synergistic control of micro-/macro-structures is a novel concept in energy material processing that has considerable potential for providing unprecedented control of electrode structures, thereby enhancing performance. Electrochemical tests have shown that these new electrodes exhibit superior performance in their specific capacity, areal capacity, and life cycle.

Determination of macro-scale soil properties from pore-scale structures: model derivation.

PubMed

Daly, K R; Roose, T

2018-01-01

In this paper, we use homogenization to derive a set of macro-scale poro-elastic equations for soils composed of rigid solid particles, air-filled pore space and a poro-elastic mixed phase. We consider the derivation in the limit of large deformation and show that by solving representative problems on the micro-scale we can parametrize the macro-scale equations. To validate the homogenization procedure, we compare the predictions of the homogenized equations with those of the full equations for a range of different geometries and material properties. We show that the results differ by [Formula: see text] for all cases considered. The success of the homogenization scheme means that it can be used to determine the macro-scale poro-elastic properties of soils from the underlying structure. Hence, it will prove a valuable tool in both characterization and optimization.

Interspecies scaling and prediction of human clearance: comparison of small- and macro-molecule drugs

PubMed Central

Huh, Yeamin; Smith, David E.; Feng, Meihau Rose

2014-01-01

Human clearance prediction for small- and macro-molecule drugs was evaluated and compared using various scaling methods and statistical analysis.Human clearance is generally well predicted using single or multiple species simple allometry for macro- and small-molecule drugs excreted renally.The prediction error is higher for hepatically eliminated small-molecules using single or multiple species simple allometry scaling, and it appears that the prediction error is mainly associated with drugs with low hepatic extraction ratio (Eh). The error in human clearance prediction for hepatically eliminated small-molecules was reduced using scaling methods with a correction of maximum life span (MLP) or brain weight (BRW).Human clearance of both small- and macro-molecule drugs is well predicted using the monkey liver blood flow method. Predictions using liver blood flow from other species did not work as well, especially for the small-molecule drugs. PMID:21892879

The effect of the length of macro synthetic fibres on their performance in concrete

NASA Astrophysics Data System (ADS)

Juhász, K. P.; Kis, V.

2017-09-01

Nowadays macro synthetic fibres are able to compete with steel fibres despite their low Youngs Modulus. This is due to their different pull-out mechanism and a larger number of individual fibres per kilo compared to steel fibres. Macro synthetic fibres bond to the concrete along their full length, usually with an embossed surface, while steel fibres are mostly anchored by their hooked ends. If the bond is defined by the length of the embossed surface, logically the longer the synthetic fibre the higher post-crack capacity. In this paper the same type of macro synthetic fibre was researched with different lengths but at the same dosage. The consistency of the fresh concrete together with the quality of the distribution of the fibres have been analysed and compared with the residual strength. After analysing these data the optimum fibre length was able to be determined.

An Introduction to Macro- Level Spatial Nonstationarity: a Geographically Weighted Regression Analysis of Diabetes and Poverty.

PubMed

Siordia, Carlos; Saenz, Joseph; Tom, Sarah E

2012-01-01

Type II diabetes is a growing health problem in the United States. Understanding geographic variation in diabetes prevalence will inform where resources for management and prevention should be allocated. Investigations of the correlates of diabetes prevalence have largely ignored how spatial nonstationarity might play a role in the macro-level distribution of diabetes. This paper introduces the reader to the concept of spatial nonstationarity-variance in statistical relationships as a function of geographical location. Since spatial nonstationarity means different predictors can have varying effects on model outcomes, we make use of a geographically weighed regression to calculate correlates of diabetes as a function of geographic location. By doing so, we demonstrate an exploratory example in which the diabetes-poverty macro-level statistical relationship varies as a function of location. In particular, we provide evidence that when predicting macro-level diabetes prevalence, poverty is not always positively associated with diabetes.

Macro-level gender equality and depression in men and women in Europe.

PubMed

Van de Velde, Sarah; Huijts, Tim; Bracke, Piet; Bambra, Clare

2013-06-01

A recurrent finding in international literature is a greater prevalence of depression in women than in men. While explanations for this gender gap have been studied extensively at the individual level, few researchers have studied macro-level determinants of depression in men and women. In the current study we aim to examine the micro-macro linkage of the relationship between gender equality and depression by gender in Europe, using data from the European Social Survey, 2006-2007 (N=39,891). Using a multilevel framework we find that a high degree of macro-level gender equality is related to lower levels of depression in both women and men. It is also related to a smaller gender difference in depression, but only for certain social subgroups and only for specific dimensions of gender equality. © 2013 The Authors. Sociology of Health & Illness © 2013 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

Full complex spatial filtering with a phase mostly DMD. [Deformable Mirror Device

NASA Technical Reports Server (NTRS)

Florence, James M.; Juday, Richard D.

1991-01-01

A new technique for implementing fully complex spatial filters with a phase mostly deformable mirror device (DMD) light modulator is described. The technique combines two or more phase-modulating flexure-beam mirror elements into a single macro-pixel. By manipulating the relative phases of the individual sub-pixels within the macro-pixel, the amplitude and the phase can be independently set for this filtering element. The combination of DMD sub-pixels into a macro-pixel is accomplished by adjusting the optical system resolution, thereby trading off system space bandwidth product for increased filtering flexibility. Volume in the larger dimensioned space, space bandwidth-complex axes count, is conserved. Experimental results are presented mapping out the coupled amplitude and phase characteristics of the individual flexure-beam DMD elements and demonstrating the independent control of amplitude and phase in a combined macro-pixel. This technique is generally applicable for implementation with any type of phase modulating light modulator.

Efficient Monte Carlo sampling of inverse problems using a neural network-based forward—applied to GPR crosshole traveltime inversion

NASA Astrophysics Data System (ADS)

Hansen, T. M.; Cordua, K. S.

2017-12-01

Probabilistically formulated inverse problems can be solved using Monte Carlo-based sampling methods. In principle, both advanced prior information, based on for example, complex geostatistical models and non-linear forward models can be considered using such methods. However, Monte Carlo methods may be associated with huge computational costs that, in practice, limit their application. This is not least due to the computational requirements related to solving the forward problem, where the physical forward response of some earth model has to be evaluated. Here, it is suggested to replace a numerical complex evaluation of the forward problem, with a trained neural network that can be evaluated very fast. This will introduce a modeling error that is quantified probabilistically such that it can be accounted for during inversion. This allows a very fast and efficient Monte Carlo sampling of the solution to an inverse problem. We demonstrate the methodology for first arrival traveltime inversion of crosshole ground penetrating radar data. An accurate forward model, based on 2-D full-waveform modeling followed by automatic traveltime picking, is replaced by a fast neural network. This provides a sampling algorithm three orders of magnitude faster than using the accurate and computationally expensive forward model, and also considerably faster and more accurate (i.e. with better resolution), than commonly used approximate forward models. The methodology has the potential to dramatically change the complexity of non-linear and non-Gaussian inverse problems that have to be solved using Monte Carlo sampling techniques.

Probabilistic treatment of the uncertainty from the finite size of weighted Monte Carlo data

NASA Astrophysics Data System (ADS)

Glüsenkamp, Thorsten

2018-06-01

Parameter estimation in HEP experiments often involves Monte Carlo simulation to model the experimental response function. A typical application are forward-folding likelihood analyses with re-weighting, or time-consuming minimization schemes with a new simulation set for each parameter value. Problematically, the finite size of such Monte Carlo samples carries intrinsic uncertainty that can lead to a substantial bias in parameter estimation if it is neglected and the sample size is small. We introduce a probabilistic treatment of this problem by replacing the usual likelihood functions with novel generalized probability distributions that incorporate the finite statistics via suitable marginalization. These new PDFs are analytic, and can be used to replace the Poisson, multinomial, and sample-based unbinned likelihoods, which covers many use cases in high-energy physics. In the limit of infinite statistics, they reduce to the respective standard probability distributions. In the general case of arbitrary Monte Carlo weights, the expressions involve the fourth Lauricella function FD, for which we find a new finite-sum representation in a certain parameter setting. The result also represents an exact form for Carlson's Dirichlet average Rn with n > 0, and thereby an efficient way to calculate the probability generating function of the Dirichlet-multinomial distribution, the extended divided difference of a monomial, or arbitrary moments of univariate B-splines. We demonstrate the bias reduction of our approach with a typical toy Monte Carlo problem, estimating the normalization of a peak in a falling energy spectrum, and compare the results with previously published methods from the literature.

Human Responses to Climate Variability: The Case of South Africa

NASA Astrophysics Data System (ADS)

Oppenheimer, M.; Licker, R.; Mastrorillo, M.; Bohra-Mishra, P.; Estes, L. D.; Cai, R.

2014-12-01

Climate variability has been associated with a range of societal and individual outcomes including migration, violent conflict, changes in labor productivity, and health impacts. Some of these may be direct responses to changes in mean temperature or precipitation or extreme events, such as displacement of human populations by tropical cyclones. Others may be mediated by a variety of biological, social, or ecological factors such as migration in response to long-term changes in crops yields. Research is beginning to elucidate and distinguish the many channels through which climate variability may influence human behavior (ranging from the individual to the collective, societal level) in order to better understand how to improve resilience in the face of current variability as well as future climate change. Using a variety of data sets from South Africa, we show how climate variability has influenced internal (within country) migration in recent history. We focus on South Africa as it is a country with high levels of internal migration and dramatic temperature and precipitation changes projected for the 21st century. High poverty rates and significant levels of rain-fed, smallholder agriculture leave large portions of South Africa's population base vulnerable to future climate change. In this study, we utilize two complementary statistical models - one micro-level model, driven by individual and household level survey data, and one macro-level model, driven by national census statistics. In both models, we consider the effect of climate on migration both directly (with gridded climate reanalysis data) and indirectly (with agricultural production statistics). With our historical analyses of climate variability, we gain insights into how the migration decisions of South Africans may be influenced by future climate change. We also offer perspective on the utility of micro and macro level approaches in the study of climate change and human migration.

TU-H-CAMPUS-IeP1-01: Bias and Computational Efficiency of Variance Reduction Methods for the Monte Carlo Simulation of Imaging Detectors

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

Sharma, D; Badano, A; Sempau, J

Purpose: Variance reduction techniques (VRTs) are employed in Monte Carlo simulations to obtain estimates with reduced statistical uncertainty for a given simulation time. In this work, we study the bias and efficiency of a VRT for estimating the response of imaging detectors. Methods: We implemented Directed Sampling (DS), preferentially directing a fraction of emitted optical photons directly towards the detector by altering the isotropic model. The weight of each optical photon is appropriately modified to maintain simulation estimates unbiased. We use a Monte Carlo tool called fastDETECT2 (part of the hybridMANTIS open-source package) for optical transport, modified for VRT. Themore » weight of each photon is calculated as the ratio of original probability (no VRT) and the new probability for a particular direction. For our analysis of bias and efficiency, we use pulse height spectra, point response functions, and Swank factors. We obtain results for a variety of cases including analog (no VRT, isotropic distribution), and DS with 0.2 and 0.8 optical photons directed towards the sensor plane. We used 10,000, 25-keV primaries. Results: The Swank factor for all cases in our simplified model converged fast (within the first 100 primaries) to a stable value of 0.9. The root mean square error per pixel for DS VRT for the point response function between analog and VRT cases was approximately 5e-4. Conclusion: Our preliminary results suggest that DS VRT does not affect the estimate of the mean for the Swank factor. Our findings indicate that it may be possible to design VRTs for imaging detector simulations to increase computational efficiency without introducing bias.« less

The visible signal responsible for proton therapy dosimetry using bare optical fibers is not Čerenkov radiation.

PubMed

Darafsheh, Arash; Taleei, Reza; Kassaee, Alireza; Finlay, Jarod C

2016-11-01

Proton beam dosimetry using bare plastic optical fibers has emerged as a simple approach to proton beam dosimetry. The source of the signal in this method has been attributed to Čerenkov radiation. The aim of this work was a phenomenological study of the nature of the visible light responsible for the signal in bare fiber optic dosimetry of proton therapy beams. Plastic fiber optic probes embedded in solid water phantoms were irradiated with proton beams of energies 100, 180, and 225 MeV produced by a proton therapy cyclotron. Luminescence spectroscopy was performed by a CCD-coupled spectrometer. The spectra were acquired at various depths in phantom to measure the percentage depth dose (PDD) for each beam energy. For comparison, the PDD curves were acquired using a standard multilayer ion chamber device. In order to further analyze the contribution of the Čerenkov radiation in the spectra, Monte Carlo simulation was performed using fluka Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and optical emission of Čerenkov radiation. The measured depth doses using the bare fiber are in agreement with measurements performed by the multilayer ion chamber device, indicating the feasibility of using bare fiber probes for proton beam dosimetry. The spectroscopic study of proton-irradiated fibers showed a continuous spectrum with a shape different from that of Čerenkov radiation. The Monte Carlo simulations confirmed that the amount of the generated Čerenkov light does not follow the radiation absorbed dose in a medium. The source of the optical signal responsible for the proton dose measurement using bare optical fibers is not Čerenkov radiation. It is fluorescence of the plastic material of the fiber.

Application of a color scanner for 60Co high dose rate brachytherapy dosimetry with EBT radiochromic film

PubMed Central

Ghorbani, Mahdi; Toossi, Mohammad Taghi Bahreyni; Mowlavi, Ali Asghar; Roodi, Shahram Bayani; Meigooni, Ali Soleimani

2012-01-01

Background. The aim of this study is to evaluate the performance of a color scanner as a radiochromic film reader in two dimensional dosimetry around a high dose rate brachytherapy source. Materials and methods A Microtek ScanMaker 1000XL film scanner was utilized for the measurement of dose distribution around a high dose rate GZP6 60Co brachytherapy source with GafChromic® EBT radiochromic films. In these investigations, the non-uniformity of the film and scanner response, combined, as well as the films sensitivity to scanner’s light source was evaluated using multiple samples of films, prior to the source dosimetry. The results of these measurements were compared with the Monte Carlo simulated data using MCNPX code. In addition, isodose curves acquired by radiochromic films and Monte Carlo simulation were compared with those provided by the GZP6 treatment planning system. Results Scanning of samples of uniformly irradiated films demonstrated approximately 2.85% and 4.97% nonuniformity of the response, respectively in the longitudinal and transverse directions of the film. Our findings have also indicated that the film response is not affected by the exposure to the scanner’s light source, particularly in multiple scanning of film. The results of radiochromic film measurements are in good agreement with the Monte Carlo calculations (4%) and the corresponding dose values presented by the GZP6 treatment planning system (5%). Conclusions The results of these investigations indicate that the Microtek ScanMaker 1000XL color scanner in conjunction with GafChromic EBT film is a reliable system for dosimetric evaluation of a high dose rate brachytherapy source. PMID:23411947

A Novel ImageJ Macro for Automated Cell Death Quantitation in the Retina

PubMed Central

Maidana, Daniel E.; Tsoka, Pavlina; Tian, Bo; Dib, Bernard; Matsumoto, Hidetaka; Kataoka, Keiko; Lin, Haijiang; Miller, Joan W.; Vavvas, Demetrios G.

2015-01-01

Purpose TUNEL assay is widely used to evaluate cell death. Quantification of TUNEL-positive (TUNEL+) cells in tissue sections is usually performed manually, ideally by two masked observers. This process is time consuming, prone to measurement errors, and not entirely reproducible. In this paper, we describe an automated quantification approach to address these difficulties. Methods We developed an ImageJ macro to quantitate cell death by TUNEL assay in retinal cross-section images. The script was coded using IJ1 programming language. To validate this tool, we selected a dataset of TUNEL assay digital images, calculated layer area and cell count manually (done by two observers), and compared measurements between observers and macro results. Results The automated macro segmented outer nuclear layer (ONL) and inner nuclear layer (INL) successfully. Automated TUNEL+ cell counts were in-between counts of inexperienced and experienced observers. The intraobserver coefficient of variation (COV) ranged from 13.09% to 25.20%. The COV between both observers was 51.11 ± 25.83% for the ONL and 56.07 ± 24.03% for the INL. Comparing observers' results with macro results, COV was 23.37 ± 15.97% for the ONL and 23.44 ± 18.56% for the INL. Conclusions We developed and validated an ImageJ macro that can be used as an accurate and precise quantitative tool for retina researchers to achieve repeatable, unbiased, fast, and accurate cell death quantitation. We believe that this standardized measurement tool could be advantageous to compare results across different research groups, as it is freely available as open source. PMID:26469755

Inter-level Scaffolding and Sequences of Representational Activities in Teaching a Chemical System with Graphical Simulations

NASA Astrophysics Data System (ADS)

Li, Na; Black, John B.

2016-10-01

Chemistry knowledge can be represented at macro-, micro- and symbolic levels, and learning a chemistry topic requires students to engage in multiple representational activities. This study focused on scaffolding for inter-level connection-making in learning chemistry knowledge with graphical simulations. We also tested whether different sequences of representational activities produced different student learning outcomes in learning a chemistry topic. A sample of 129 seventh graders participated in this study. In a simulation-based environment, participants completed three representational activities to learn several ideal gas law concepts. We conducted a 2 × 3 factorial design experiment. We compared two scaffolding conditions: (1) the inter- level scaffolding condition in which participants received inter-level questions and experienced the dynamic link function in the simulation-based environment and (2) the intra- level scaffolding condition in which participants received intra-level questions and did not experience the dynamic link function. We also compared three different sequences of representational activities: macro-symbolic-micro, micro-symbolic-macro and symbolic-micro-macro. For the scaffolding variable, we found that the inter- level scaffolding condition produced significantly better performance in both knowledge comprehension and application, compared to the intra- level scaffolding condition. For the sequence variable, we found that the macro-symbolic-micro sequence produced significantly better knowledge comprehension performance than the other two sequences; however, it did not benefit knowledge application performance. There was a trend that the treatment group who experienced inter- level scaffolding and the micro-symbolic-macro sequence achieved the best knowledge application performance.

Bringing consistency to simulation of population models--Poisson simulation as a bridge between micro and macro simulation.

PubMed

Gustafsson, Leif; Sternad, Mikael

2007-10-01

Population models concern collections of discrete entities such as atoms, cells, humans, animals, etc., where the focus is on the number of entities in a population. Because of the complexity of such models, simulation is usually needed to reproduce their complete dynamic and stochastic behaviour. Two main types of simulation models are used for different purposes, namely micro-simulation models, where each individual is described with its particular attributes and behaviour, and macro-simulation models based on stochastic differential equations, where the population is described in aggregated terms by the number of individuals in different states. Consistency between micro- and macro-models is a crucial but often neglected aspect. This paper demonstrates how the Poisson Simulation technique can be used to produce a population macro-model consistent with the corresponding micro-model. This is accomplished by defining Poisson Simulation in strictly mathematical terms as a series of Poisson processes that generate sequences of Poisson distributions with dynamically varying parameters. The method can be applied to any population model. It provides the unique stochastic and dynamic macro-model consistent with a correct micro-model. The paper also presents a general macro form for stochastic and dynamic population models. In an appendix Poisson Simulation is compared with Markov Simulation showing a number of advantages. Especially aggregation into state variables and aggregation of many events per time-step makes Poisson Simulation orders of magnitude faster than Markov Simulation. Furthermore, you can build and execute much larger and more complicated models with Poisson Simulation than is possible with the Markov approach.

Time-resolved diode dosimetry calibration through Monte Carlo modeling for in vivo passive scattered proton therapy range verification.

PubMed

Toltz, Allison; Hoesl, Michaela; Schuemann, Jan; Seuntjens, Jan; Lu, Hsiao-Ming; Paganetti, Harald

2017-11-01

Our group previously introduced an in vivo proton range verification methodology in which a silicon diode array system is used to correlate the dose rate profile per range modulation wheel cycle of the detector signal to the water-equivalent path length (WEPL) for passively scattered proton beam delivery. The implementation of this system requires a set of calibration data to establish a beam-specific response to WEPL fit for the selected 'scout' beam (a 1 cm overshoot of the predicted detector depth with a dose of 4 cGy) in water-equivalent plastic. This necessitates a separate set of measurements for every 'scout' beam that may be appropriate to the clinical case. The current study demonstrates the use of Monte Carlo simulations for calibration of the time-resolved diode dosimetry technique. Measurements for three 'scout' beams were compared against simulated detector response with Monte Carlo methods using the Tool for Particle Simulation (TOPAS). The 'scout' beams were then applied in the simulation environment to simulated water-equivalent plastic, a CT of water-equivalent plastic, and a patient CT data set to assess uncertainty. Simulated detector response in water-equivalent plastic was validated against measurements for 'scout' spread out Bragg peaks of range 10 cm, 15 cm, and 21 cm (168 MeV, 177 MeV, and 210 MeV) to within 3.4 mm for all beams, and to within 1 mm in the region where the detector is expected to lie. Feasibility has been shown for performing the calibration of the detector response for three 'scout' beams through simulation for the time-resolved diode dosimetry technique in passive scattered proton delivery. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Impact of Uncertainties in Exposure Assessment on Thyroid Cancer Risk among Persons in Belarus Exposed as Children or Adolescents Due to the Chernobyl Accident.

PubMed

Little, Mark P; Kwon, Deukwoo; Zablotska, Lydia B; Brenner, Alina V; Cahoon, Elizabeth K; Rozhko, Alexander V; Polyanskaya, Olga N; Minenko, Victor F; Golovanov, Ivan; Bouville, André; Drozdovitch, Vladimir

2015-01-01

The excess incidence of thyroid cancer in Ukraine and Belarus observed a few years after the Chernobyl accident is considered to be largely the result of 131I released from the reactor. Although the Belarus thyroid cancer prevalence data has been previously analyzed, no account was taken of dose measurement error. We examined dose-response patterns in a thyroid screening prevalence cohort of 11,732 persons aged under 18 at the time of the accident, diagnosed during 1996-2004, who had direct thyroid 131I activity measurement, and were resident in the most radio-actively contaminated regions of Belarus. Three methods of dose-error correction (regression calibration, Monte Carlo maximum likelihood, Bayesian Markov Chain Monte Carlo) were applied. There was a statistically significant (p<0.001) increasing dose-response for prevalent thyroid cancer, irrespective of regression-adjustment method used. Without adjustment for dose errors the excess odds ratio was 1.51 Gy- (95% CI 0.53, 3.86), which was reduced by 13% when regression-calibration adjustment was used, 1.31 Gy- (95% CI 0.47, 3.31). A Monte Carlo maximum likelihood method yielded an excess odds ratio of 1.48 Gy- (95% CI 0.53, 3.87), about 2% lower than the unadjusted analysis. The Bayesian method yielded a maximum posterior excess odds ratio of 1.16 Gy- (95% BCI 0.20, 4.32), 23% lower than the unadjusted analysis. There were borderline significant (p = 0.053-0.078) indications of downward curvature in the dose response, depending on the adjustment methods used. There were also borderline significant (p = 0.102) modifying effects of gender on the radiation dose trend, but no significant modifying effects of age at time of accident, or age at screening as modifiers of dose response (p>0.2). In summary, the relatively small contribution of unshared classical dose error in the current study results in comparatively modest effects on the regression parameters.

Usual Dietary Intakes: SAS Macros for the NCI Method

Cancer.gov

SAS macros are currently available to facilitate modeling of a single dietary component, whether consumed daily or episodically; ratios of two dietary components that are consumed nearly every day; multiple dietary components, whether consumed daily or episodically.

Organizational Responsibility for Age-Friendly Social Participation: Views of Australian Rural Community Stakeholders.

PubMed

Winterton, Rachel

2016-01-01

This qualitative study critically explores the barriers experienced by diverse rural community stakeholders in facilitating environments that enable age-friendly social participation. Twenty-six semi-structured interviews were conducted across two rural Australian communities with stakeholders from local government, health, social care, and community organizations. Findings identify that rural community stakeholders face significant difficulties in securing resources for groups and activities catering to older adults, which subsequently impacts their capacity to undertake outreach to older adults. However, in discussing these issues, questions were raised in relation to whose responsibility it is to provide resources for community groups and organizations providing social initiatives and whose responsibility it is to engage isolated seniors. These findings provide a much-needed critical perspective on current age-friendly research by acknowledging the responsibilities of various macro-level social structures-different community-level organizations, local government, and policy in fostering environments to enable participation of diverse rural older adults.

Secondary students' views about scientific inquiry

NASA Astrophysics Data System (ADS)

Galano, Silvia; Zappia, Alessandro; Smaldone, Luigi; Testa, Italo

2016-05-01

In this study we investigated the views about Scientific Inquiry (SI) of about 300 students at the beginning of the secondary school course (14-15years old). An adapted version of the Views On Scientific Inquiry (VOSI) questionnaire was used as research instrument. The questionnaire, focused on six specific aspects of SI, was submitted before and after a six-hours in-classroom delivery of a teaching-learning sequence (TLS) that targeted explicitly the six SI aspects. We first analyzed responses using a five-level categorization: a) informed view; b) mixed or partially correct view; c) naıve view; d) unclear; e) not given. Two independent researchers iteratively analyzed the data with a final inter-rater reliability of about 90%. Then, we collapsed the initial categories into three macro-categories: C1) informed/partial view; C2) naıve view; C3) unclear or not given; and calculated the shift in the macro-categorization between pre- and post-test. Finally, we investigated a possible relationship between how the TLSs were enacted and the students' achievements. Data show that the percentage of students' informed responses only slightly increased between pre- and post-test in the majority of the targeted aspects. Moreover, students' achievements seem to depend on how the teachers enacted the TLSs. Our results suggest that short inquiry-based teaching interventions are not sufficient to effectively teach SI aspects. Moreover, our results suggest to develop specific training courses aimed at improving teachers' own beliefs and practices about SI.

Can agent based models effectively reduce fisheries management implementation uncertainty?

NASA Astrophysics Data System (ADS)

Drexler, M.

2016-02-01

Uncertainty is an inherent feature of fisheries management. Implementation uncertainty remains a challenge to quantify often due to unintended responses of users to management interventions. This problem will continue to plague both single species and ecosystem based fisheries management advice unless the mechanisms driving these behaviors are properly understood. Equilibrium models, where each actor in the system is treated as uniform and predictable, are not well suited to forecast the unintended behaviors of individual fishers. Alternatively, agent based models (AMBs) can simulate the behaviors of each individual actor driven by differing incentives and constraints. This study evaluated the feasibility of using AMBs to capture macro scale behaviors of the US West Coast Groundfish fleet. Agent behavior was specified at the vessel level. Agents made daily fishing decisions using knowledge of their own cost structure, catch history, and the histories of catch and quota markets. By adding only a relatively small number of incentives, the model was able to reproduce highly realistic macro patterns of expected outcomes in response to management policies (catch restrictions, MPAs, ITQs) while preserving vessel heterogeneity. These simulations indicate that agent based modeling approaches hold much promise for simulating fisher behaviors and reducing implementation uncertainty. Additional processes affecting behavior, informed by surveys, are continually being added to the fisher behavior model. Further coupling of the fisher behavior model to a spatial ecosystem model will provide a fully integrated social, ecological, and economic model capable of performing management strategy evaluations to properly consider implementation uncertainty in fisheries management.

[Horizon scanning in preparation for future health threats: a pilot exercise conducted by the French Institute for Public Health Surveillance in 2014].

PubMed

Eilstein, Daniel; Xerri, Bertrand; Viso, Anne-Catherine; Therre, Hélène; Gorza, Maud; Fuchs, Doriane; Pozuelos, Jérôme; Ioos, Sophie; Che, Didier; Bertrand, Edwige; El Yamani, Mounia; Empereur-Bissonnet, Pascal; Duport, Nicolas; Desenclos, Jean-Claude

2016-01-01

Background: Health surveillance is a reactive process, with no real hindsight for dealing with signals and alerts. It may fail to detect more radical changes with a major medium-term or long-term impact on public health. To increase proactivity, the French Institute for Public Health Surveillance has opted for a prospective monitoring approach.Methods: Several steps were necessary: 1) Identification of public health determinants. 2) Identification of key variables based on a combination of determinants. Variables were classified into three groups (health event trigger factors, dissemination factors and response factors) and were submitted to future development assumptions. 3) Identification, in each of the three groups, of micro-scenarios derived from variable trends. 4) Identification of macro-scenarios, each built from the three micro-scenarios for each of the three groups. 5) Identification of issues for the future of public health.Results: The exercise identified 22 key variables, 17 micro-scenarios and 5 macro-scenarios. The topics retained relate to issues on social and territorial health inequalities, health burden, individual and collective responsibilities in terms of health, ethical aspects, emerging phenomena, ‘Big data’, data mining, new health technologies, interlocking of analysis scales.Conclusions: The approach presented here guides the programming of activities of a health safety agency, particularly for monitoring and surveillance. By describing possible future scenarios, health surveillance can help decision-makers to influence the context towards one or more favourable futures.

The double burden of neoliberalism? Noncommunicable disease policies and the global political economy of risk.

PubMed

Glasgow, Sara; Schrecker, Ted

2016-05-01

The growing prevalence of NCDs in low- and middle-income countries (LMICs) is now recognized as one of the major global health policy issues of the early 21st century. Current official approaches reflect ambivalence about how health policy should approach the social determinants of health identified by the WHO Commission on the topic that released its report in 2008, and in particular the role of macro-scale economic and social processes. Authoritative framing of options for NCD prevention in advance of the September, 2011 UN high-level meeting on NCDs arguably relied on a selective reading of the scientific (including social scientific) evidence, and foregrounded a limited number of risk factors defined in terms of individual behavior: tobacco use, unhealthy diet, alcohol (ab)use and physical inactivity. The effect was to reproduce at a transnational level the individualization of responsibility for health that characterizes most health promotion initiatives in high-income countries, ignoring both the limited control that many people have over their exposure to these risk factors and the contribution of macro-scale processes like trade liberalization and the marketing activities of transnational corporations to the global burden of NCDs. An alternative perspective focuses on "the inequitable distribution of power, money, and resources" described by the WHO Commission, and the ways in which policies that address those inequities can avoid unintentional incorporation of neoliberal constructions of risk and responsibility. Copyright © 2016. Published by Elsevier Ltd.

The double burden of neoliberalism? Noncommunicable disease policies and the global political economy of risk.

PubMed

Glasgow, Sara; Schrecker, Ted

2015-07-01

The growing prevalence of NCDs in low- and middle-income countries (LMICs) is now recognized as one of the major global health policy issues of the early 21st century. Current official approaches reflect ambivalence about how health policy should approach the social determinants of health identified by the WHO Commission on the topic that released its report in 2008, and in particular the role of macro-scale economic and social processes. Authoritative framing of options for NCD prevention in advance of the September, 2011 UN high-level meeting on NCDs arguably relied on a selective reading of the scientific (including social scientific) evidence, and foregrounded a limited number of risk factors defined in terms of individual behavior: tobacco use, unhealthy diet, alcohol (ab)use and physical inactivity. The effect was to reproduce at a transnational level the individualization of responsibility for health that characterizes most health promotion initiatives in high-income countries, ignoring both the limited control that many people have over their exposure to these risk factors and the contribution of macro-scale processes like trade liberalization and the marketing activities of transnational corporations to the global burden of NCDs. An alternative perspective focuses on "the inequitable distribution of power, money, and resources" described by the WHO Commission, and the ways in which policies that address those inequities can avoid unintentional incorporation of neoliberal constructions of risk and responsibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Common functional targets of adaptive micro- and macro-evolutionary divergence in killifish.

PubMed

Whitehead, Andrew; Zhang, Shujun; Roach, Jennifer L; Galvez, Fernando

2013-07-01

Environmental salinity presents a key barrier to dispersal for most aquatic organisms, and adaptation to alternate osmotic environments likely enables species diversification. Little is known of the functional basis for derived tolerance to environmental salinity. We integrate comparative physiology and functional genomics to explore the mechanistic underpinnings of evolved variation in osmotic plasticity within and among two species of killifish; Fundulus majalis harbours the ancestral mainly salt-tolerant phenotype, whereas Fundulus heteroclitus harbours a derived physiology that retains extreme salt tolerance but with expanded osmotic plasticity towards the freshwater end of the osmotic continuum. Common-garden comparative hypo-osmotic challenge experiments show that F. heteroclitus is capable of remodelling gill epithelia more quickly and at more extreme osmotic challenge than F. majalis. We detect an unusual pattern of baseline transcriptome divergence, where neutral evolutionary processes appear to govern expression divergence within species, but patterns of divergence for these genes between species do not follow neutral expectations. During acclimation, genome expression profiling identifies mechanisms of acclimation-associated response that are conserved within the genus including regulation of paracellular permeability. In contrast, several responses vary among species including those putatively associated with cell volume regulation, and these same mechanisms are targets for adaptive physiological divergence along osmotic gradients within F. heteroclitus. As such, the genomic and physiological mechanisms that are associated with adaptive fine-tuning within species also contribute to macro-evolutionary divergence as species diversify across osmotic niches. © 2013 John Wiley & Sons Ltd.

Assessing combined impacts of agrochemicals: Aquatic macroinvertebrate population responses in outdoor mesocosms.

PubMed

Barmentlo, S Henrik; Schrama, Maarten; Hunting, Ellard R; Heutink, Roel; van Bodegom, Peter M; de Snoo, Geert R; Vijver, Martina G

2018-08-01

Agricultural ditches host a diverse community of species. These species often are unwarrantedly exposed to fertilizers and a wide-array of pesticides (hereafter: agrochemicals). Standardized ecotoxicological research provides valuable information to predict whether these pesticides possibly pose a threat to the organisms living within these ditches, in particular macro-invertebrates. However, knowledge on how mixtures of these agrochemicals affect macro-invertebrates under realistic abiotic conditions and with population and community complexity is mostly lacking. Therefore we examined here, using a full factorial design, the population responses of macroinvertebrate species assemblages exposed to environmentally relevant concentrations of three commonly used agrochemicals (for 35days) in an outdoor experiment. The agrochemicals selected were an insecticide (imidacloprid), herbicide (terbuthylazine) and nutrients (NPK), all having a widespread usage and often detected together in watersheds. Effects on species abundance and body length caused by binary mixture combinations could be described from single substance exposure. However, when agrochemicals were applied as tertiary mixtures, as they are commonly found in agricultural waters, species' abundance often deviated from expectations made based on the three single treatments. This indicates that pesticide-mixture induced toxicity to population relevant endpoints are difficult to extrapolate to field conditions. As in agricultural ditches often a multitude (approx. up to 7) of agrochemicals residues are detected, we call other scientist to verify the ecological complexity of non-additive induced shifts in natural aquatic invertebrate populations and aquatic species assemblages. Copyright © 2018 Elsevier B.V. All rights reserved.

Potential Effects of Climate Change on the Water Level, Flora and Macro-fauna of a Large Neotropical Wetland

PubMed Central

Úbeda, Bárbara; Di Giacomo, Adrian S.; Neiff, Juan José; Loiselle, Steven A.; Guadalupe Poi, Alicia S.; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

Possible consequences of climate change in one of the world’s largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

An integrated analysis of micro- and macro-habitat features as a tool to detect weather-driven constraints: A case study with cavity nesters.

PubMed

Campobello, D; Lindström, J; Di Maggio, R; Sarà, M

2017-01-01

The effects of climate change on animal populations may be shaped by habitat characteristics at both micro- and macro-habitat level, however, empirical studies integrating these two scales of observation are lacking. As analyses of the effects of climate change commonly rely on data from a much larger scale than the microhabitat level organisms are affected at, this mismatch risks hampering progress in developing understanding of the details of the ecological and evolutionary responses of organisms and, ultimately, effective actions to preserve their populations. Cavity nesters, often with a conservation status of concern, are an ideal model because the cavity is a microenvironment potentially different from the macroenvironment but nonetheless inevitably interacting with it. The lesser kestrel (Falco naumanni) is a cavity nester which was until recently classified by as Vulnerable species. Since 2004, for nine years, we collected detailed biotic and abiotic data at both micro- and macro-scales of observation in a kestrel population breeding in the Gela Plain (Italy), a Mediterranean area where high temperatures may reach lethal values for the nest content. We show that macroclimatic features needed to be integrated with both abiotic and biotic factors recorded at a microscale before reliably predicting nest temperatures. Among the nest types used by lesser kestrels, we detected a preferential occupation of the cooler nest types, roof tiles, by early breeders whereas, paradoxically, late breeders nesting with hotter temperatures occupied the overheated nest holes. Not consistent with such a suggested nest selection, the coolest nest type did not host a higher reproductive success than the overheated nests. We discussed our findings in the light of cavity temperatures and nest types deployed within conservation actions assessed by integrating selected factors at different observation scales.

The institutional logic of integrated care: an ethnography of patient transitions.

PubMed

Shaw, James A; Kontos, Pia; Martin, Wendy; Victor, Christina

2017-03-20

Purpose The purpose of this paper is to use theories of institutional logics and institutional entrepreneurship to examine how and why macro-, meso-, and micro-level influences inter-relate in the implementation of integrated transitional care out of hospital in the English National Health Service. Design/methodology/approach The authors conducted an ethnographic case study of a hospital and surrounding services within a large urban centre in England. Specific methods included qualitative interviews with patients/caregivers, health/social care providers, and organizational leaders; observations of hospital transition planning meetings, community "hub" meetings, and other instances of transition planning; reviews of patient records; and analysis of key policy documents. Analysis was iterative and informed by theory on institutional logics and institutional entrepreneurship. Findings Organizational leaders at the meso-level of health and social care promoted a partnership logic of integrated care in response to conflicting institutional ideas found within a key macro-level policy enacted in 2003 (The Community Care (Delayed Discharges) Act). Through institutional entrepreneurship at the micro-level, the partnership logic became manifest in the form of relationship work among health and social care providers; they sought to build strong interpersonal relationships to enact more integrated transitional care. Originality/value This study has three key implications. First, efforts to promote integrated care should strategically include institutional entrepreneurs at the organizational and clinical levels. Second, integrated care initiatives should emphasize relationship-building among health and social care providers. Finally, theoretical development on institutional logics should further examine the role of interpersonal relationships in facilitating the "spread" of logics between macro-, meso-, and micro-level influences on inter-organizational change.

Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.

PubMed

Úbeda, Bárbara; Di Giacomo, Adrian S; Neiff, Juan José; Loiselle, Steven A; Poi, Alicia S Guadalupe; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades.

Drought-Tolerant Corn Hybrids Yield More in Drought-Stressed Environments with No Penalty in Non-stressed Environments

PubMed Central

Adee, Eric; Roozeboom, Kraig; Balboa, Guillermo R.; Schlegel, Alan; Ciampitti, Ignacio A.

2016-01-01

The potential benefit of drought-tolerant (DT) corn (Zea mays L.) hybrids may depend on drought intensity, duration, crop growth stage (timing), and the array of drought tolerance mechanisms present in selected hybrids. We hypothesized that corn hybrids containing DT traits would produce more consistent yields compared to non-DT hybrids in the presence of drought stress. The objective of this study was to define types of production environments where DT hybrids have a yield advantage compared to non-DT hybrids. Drought tolerant and non-DT hybrid pairs of similar maturity were planted in six site-years with different soil types, seasonal evapotranspiration (ET), and vapor pressure deficit (VPD), representing a range of macro-environments. Irrigation regimes and seeding rates were used to create several micro-environments within each macro-environment. Hybrid response to the range of macro and micro-environmental stresses were characterized in terms of water use efficiency, grain yield, and environmental index. Yield advantage of DT hybrids was positively correlated with environment ET and VPD. Drought tolerant hybrids yielded 5 to 7% more than non-DT hybrids in high and medium ET environments (>430 mm ET), corresponding to seasonal VPD greater than 1200 Pa. Environmental index analysis confirmed that DT hybrids were superior in stressful environments. Yield advantage for DT hybrids appeared as yield dropped below 10.8 Mg ha-1 and averaged as much as 0.6–1 Mg ha-1 at the low yield range. Hybrids with DT technology can offer a degree of buffering against drought stress by minimizing yield reduction, but also maintaining a comparable yield potential in high yielding environments. Further studies should focus on the physiological mechanisms presented in the commercially available corn drought tolerant hybrids. PMID:27790237

An integrated analysis of micro- and macro-habitat features as a tool to detect weather-driven constraints: A case study with cavity nesters

PubMed Central

Campobello, D.; Lindström, J.; Di Maggio, R.; Sarà, M.

2017-01-01

The effects of climate change on animal populations may be shaped by habitat characteristics at both micro- and macro-habitat level, however, empirical studies integrating these two scales of observation are lacking. As analyses of the effects of climate change commonly rely on data from a much larger scale than the microhabitat level organisms are affected at, this mismatch risks hampering progress in developing understanding of the details of the ecological and evolutionary responses of organisms and, ultimately, effective actions to preserve their populations. Cavity nesters, often with a conservation status of concern, are an ideal model because the cavity is a microenvironment potentially different from the macroenvironment but nonetheless inevitably interacting with it. The lesser kestrel (Falco naumanni) is a cavity nester which was until recently classified by as Vulnerable species. Since 2004, for nine years, we collected detailed biotic and abiotic data at both micro- and macro-scales of observation in a kestrel population breeding in the Gela Plain (Italy), a Mediterranean area where high temperatures may reach lethal values for the nest content. We show that macroclimatic features needed to be integrated with both abiotic and biotic factors recorded at a microscale before reliably predicting nest temperatures. Among the nest types used by lesser kestrels, we detected a preferential occupation of the cooler nest types, roof tiles, by early breeders whereas, paradoxically, late breeders nesting with hotter temperatures occupied the overheated nest holes. Not consistent with such a suggested nest selection, the coolest nest type did not host a higher reproductive success than the overheated nests. We discussed our findings in the light of cavity temperatures and nest types deployed within conservation actions assessed by integrating selected factors at different observation scales. PMID:28319183

Using Monte Carlo Ray tracing to Understand the Vibrational Response of UN as Measured by Neutron Spectroscopy

NASA Astrophysics Data System (ADS)

Lin, J. Y. Y.; Aczel, A. A.; Abernathy, D. L.; Nagler, S. E.; Buyers, W. J. L.; Granroth, G. E.

2014-03-01

Recently neutron spectroscopy measurements, using the ARCS and SEQUOIA time-of-flight chopper spectrometers, observed an extended series of equally spaced modes in UN that are well described by quantum harmonic oscillator behavior of the N atoms. Additional contributions to the scattering are also observed. Monte Carlo ray tracing simulations with various sample kernels have allowed us to distinguish between the response from the N oscillator scattering, contributions that arise from the U partial phonon density of states (PDOS), and all forms of multiple scattering. These simulations confirm that multiple scattering contributes an ~ Q -independent background to the spectrum at the oscillator mode positions. All three of the aforementioned contributions are necessary to accurately model the experimental data. These simulations were also used to compare the T dependence of the oscillator modes in SEQUOIA data to that predicted by the binary solid model. This work was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

Investigating the response of Micromegas detector to low-energy neutrons using Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Khezripour, S.; Negarestani, A.; Rezaie, M. R.

2017-08-01

Micromegas detector has recently been used for high-energy neutron (HEN) detection, but the aim of this research is to investigate the response of the Micromegas detector to low-energy neutron (LEN). For this purpose, a Micromegas detector (with air, P10, BF3, 3He and Ar/BF3 mixture) was optimized for the detection of 60 keV neutrons using the MCNP (Monte Carlo N Particle) code. The simulation results show that the optimum thickness of the cathode is 1 mm and the optimum of microgrid location is 100 μm above the anode. The output current of this detector for Ar (3%) + BF3 (97%) mixture is greater than the other ones. This mixture is considered as the appropriate gas for the Micromegas neutron detector providing the output current for 60 keV neutrons at the level of 97.8 nA per neutron. Consecuently, this detector can be introduced as LEN detector.

Electromagnetic and neutral-weak response functions of light nuclei

NASA Astrophysics Data System (ADS)

Lovato, Alessandro

2015-10-01

A major goal of nuclear theory is to understand the strong interaction in nuclei as it manifests itself in terms of two- and many-body forces among the nuclear constituents, the protons and neutrons, and the interactions of these constituents with external electroweak probes via one- and many-body currents. Using imaginary-time projection technique, quantum Monte Carlo allows for solving the time-independent Schrödinger equation even for Hamiltonians including highly spin-isospin dependent two- and three- body forces. I will present a recent Green's function Monte Carlo calculation of the quasi-elastic electroweak response functions in light nuclei, needed to describe electron and neutrino scattering. We found that meson-exchange two-body currents generate excess transverse strength from threshold to the quasielastic to the dip region and beyond. These results challenge the conventional picture of quasi elastic inclusive scattering as being largely dominated by single-nucleon knockout processes. These findings are of particular interest for the interpretation of neutrino oscillation signals.

Monte Carlo modelling of large scale NORM sources using MCNP.

PubMed

Wallace, J D

2013-12-01

The representative Monte Carlo modelling of large scale planar sources (for comparison to external environmental radiation fields) is undertaken using substantial diameter and thin profile planar cylindrical sources. The relative impact of source extent, soil thickness and sky-shine are investigated to guide decisions relating to representative geometries. In addition, the impact of source to detector distance on the nature of the detector response, for a range of source sizes, has been investigated. These investigations, using an MCNP based model, indicate a soil cylinder of greater than 20 m diameter and of no less than 50 cm depth/height, combined with a 20 m deep sky section above the soil cylinder, are needed to representatively model the semi-infinite plane of uniformly distributed NORM sources. Initial investigation of the effect of detector placement indicate that smaller source sizes may be used to achieve a representative response at shorter source to detector distances. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Critical Analysis of Dual-Probe Heat-Pulse Technique Applied to Measuring Thermal Diffusivity

NASA Astrophysics Data System (ADS)

Bovesecchi, G.; Coppa, P.; Corasaniti, S.; Potenza, M.

2018-07-01

The paper presents an analysis of the experimental parameters involved in application of the dual-probe heat pulse technique, followed by a critical review of methods for processing thermal response data (e.g., maximum detection and nonlinear least square regression) and the consequent obtainable uncertainty. Glycerol was selected as testing liquid, and its thermal diffusivity was evaluated over the temperature range from - 20 °C to 60 °C. In addition, Monte Carlo simulation was used to assess the uncertainty propagation for maximum detection. It was concluded that maximum detection approach to process thermal response data gives the closest results to the reference data inasmuch nonlinear regression results are affected by major uncertainties due to partial correlation between the evaluated parameters. Besides, the interpolation of temperature data with a polynomial to find the maximum leads to a systematic difference between measured and reference data, as put into evidence by the Monte Carlo simulations; through its correction, this systematic error can be reduced to a negligible value, about 0.8 %.

A Monte Carlo method using octree structure in photon and electron transport

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

Ogawa, K.; Maeda, S.

Most of the early Monte Carlo calculations in medical physics were used to calculate absorbed dose distributions, and detector responses and efficiencies. Recently, data acquisition in Single Photon Emission CT (SPECT) has been simulated by a Monte Carlo method to evaluate scatter photons generated in a human body and a collimator. Monte Carlo simulations in SPECT data acquisition are generally based on the transport of photons only because the photons being simulated are low energy, and therefore the bremsstrahlung productions by the electrons generated are negligible. Since the transport calculation of photons without electrons is much simpler than that withmore » electrons, it is possible to accomplish the high-speed simulation in a simple object with one medium. Here, object description is important in performing the photon and/or electron transport using a Monte Carlo method efficiently. The authors propose a new description method using an octree representation of an object. Thus even if the boundaries of each medium are represented accurately, high-speed calculation of photon transport can be accomplished because the number of voxels is much fewer than that of the voxel-based approach which represents an object by a union of the voxels of the same size. This Monte Carlo code using the octree representation of an object first establishes the simulation geometry by reading octree string, which is produced by forming an octree structure from a set of serial sections for the object before the simulation; then it transports photons in the geometry. Using the code, if the user just prepares a set of serial sections for the object in which he or she wants to simulate photon trajectories, he or she can perform the simulation automatically using the suboptimal geometry simplified by the octree representation without forming the optimal geometry by handwriting.« less

Eskers and other evidence of wet-based glaciation in Phlegra Montes, Mars.

NASA Astrophysics Data System (ADS)

Gallagher, Colman; Balme, Matt

2016-04-01

Although glacial landsystems produced under warm/wet based conditions are very common on Earth, glaciological and landform evidence indicates that glaciation on Mars during the Amazonian period (3 Ga to present) has been characterised by cold/dry based glaciers, consistent with the prevailing cold, hyperarid conditions. However, this presentation describes a system of sinuous ridges, interpreted as eskers (1), emerging from the degraded piedmont terminus of a Late Amazonian (˜150 Ma) glacier in the southern Phlegra Montes region of Mars. This is probably the first identification of martian eskers that can be directly linked to their parent glacier. Together with their contextual landform assemblage, the eskers are indicative of glacial melting and subglacial meltwater routing but the confinement of the system to a well-defined, regionally significant graben, and the absence of eskers elsewhere in the region, suggests that melting was a response to locally enhanced geothermal heat flux, rather than regional, climate-induced warming. Now, however, new observations reveal the presence of many assemblages of glacial abrasion forms and associated channels that could be evidence of more widespread wet-based glaciation in Phlegra Montes, including the collapse of several distinct ice domes. This landform assemblage has not been described in other glaciated, mid-latitude regions of the martian northern hemisphere. Moreover, Phlegra Montes are flanked by lowlands displaying evidence of extensive volcanism, including contact between plains lava and piedmont glacial ice. These observations suggest that the glaciation of Phlegra Montes might have been strongly conditioned by both volcanism and more restricted forms of ground-heating. These are important new insights both to the forcing of glacial dynamic and melting behaviour on Mars by factors other than climate and to the production of liquid water on Mars during the Late Amazonian. (1) Gallagher, C. and Balme, M. (2015). Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars, Earth and Planetary Science Letters, 431, 96-109.

INVASIVE GRASS ALTERS LITTER DECOMPOSITION BY INFLUENCING MACRO-DETRITIVORES

EPA Science Inventory

Nitrogen fertilization experiments have produced results with inconsistent rates of plant litter decomposition, a phenomenon that may be explained if the influence of animal detritivores (macro-detritivores) on litter mass loss is greater than that of microbial decomposers whose ...

Macro Analysis Tool - MAT

EPA Science Inventory

This product is an easy-to-use Excel-based macro analysis tool (MAT) for performing comparisons of air sensor data with reference data and interpreting the results. This tool tackles one of the biggest hurdles in citizen-led community air monitoring projects – working with ...

Results Of Initial Analyses Of The Salt (Macro) Batch 9 Tank 21H Qualification Samples

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

Peters, T.

2015-10-08

Savannah River National Laboratory (SRNL) analyzed samples from Tank 21H in support of qualification of Interim Salt Disposition Project (ISDP) Salt (Macro) Batch 9 for processing through the Actinide Removal Process (ARP) and the Modular Caustic-Side Solvent Extraction Unit (MCU). This document reports the initial results of the analyses of samples of Tank 21H. Analysis of the Tank 21H Salt (Macro) Batch 9 composite sample indicates that the material does not display any unusual characteristics. Further results on the chemistry and other tests will be issued in the future.

Financing health development projects: some macro-economic considerations.

PubMed

Sorkin, A L

1986-01-01

The paper briefly discusses the importance of macro-economic policy in health sector financing. The ways in which monetary and fiscal policy (macro-economic policy) affect interest rates, price levels and aggregate output are presented. The main portion of the paper considers a variety of methods for public financing of health and development projects. These approaches are analyzed in light of distributional and efficiency considerations. One way of increasing health sector resources is through reallocation from other sectors of the economy. The potential for redistribution from the defense to the health service industry is briefly considered.

Condition assessment of reinforced concrete beams using dynamic data measured with distributed long-gage macro-strain sensors

NASA Astrophysics Data System (ADS)

Hong, W.; Wu, Z. S.; Yang, C. Q.; Wan, C. F.; Wu, G.; Zhang, Y. F.

2012-06-01

A new condition assessment strategy of reinforced concrete (RC) beams is proposed in this paper. This strategy is based on frequency analysis of the dynamic data measured with distributed long-gage macro-stain sensors. After extracting modal macro-strain, the reference-based damage index is theoretically deducted in which the variations of modal flexural rigidity and modal neutral axis height are considered. The reference-free damage index is also presented for comparison. Both finite element simulation and experiment investigations were carried out to verify the proposed method. The manufacturing procedure of long-gage fiber Bragg grating (FBG) sensor chosen in the experiment is firstly presented, followed by an experimental study on the essential sensing properties of the long-gage macro-strain sensors and the results verify the excellent sensing properties, in particular the measurement accuracy and dynamic measuring capacity. Modal analysis results of a concrete beam show that the damage appearing in the beam can be well identified by the damage index while the vibration testing results of a RC beam show that the proposed method can not only capture small crack initiation but its propagation. It can be concluded that distributed long-gage dynamic macro-strain sensing technique has great potential for the condition assessment of RC structures subjected to dynamic loading.

Constraints on genes shape long-term conservation of macro-synteny in metazoan genomes.

PubMed

Lv, Jie; Havlak, Paul; Putnam, Nicholas H

2011-10-05

Many metazoan genomes conserve chromosome-scale gene linkage relationships ("macro-synteny") from the common ancestor of multicellular animal life 1234, but the biological explanation for this conservation is still unknown. Double cut and join (DCJ) is a simple, well-studied model of neutral genome evolution amenable to both simulation and mathematical analysis 5, but as we show here, it is not sufficent to explain long-term macro-synteny conservation. We examine a family of simple (one-parameter) extensions of DCJ to identify models and choices of parameters consistent with the levels of macro- and micro-synteny conservation observed among animal genomes. Our software implements a flexible strategy for incorporating genomic context into the DCJ model to incorporate various types of genomic context ("DCJ-[C]"), and is available as open source software from http://github.com/putnamlab/dcj-c. A simple model of genome evolution, in which DCJ moves are allowed only if they maintain chromosomal linkage among a set of constrained genes, can simultaneously account for the level of macro-synteny conservation and for correlated conservation among multiple pairs of species. Simulations under this model indicate that a constraint on approximately 7% of metazoan genes is sufficient to constrain genome rearrangement to an average rate of 25 inversions and 1.7 translocations per million years.

Intercalation and structural aspects of macroRAFT agents into MgAl layered double hydroxides.

PubMed

Kostadinova, Dessislava; Cenacchi Pereira, Ana; Lansalot, Muriel; D'Agosto, Franck; Bourgeat-Lami, Elodie; Leroux, Fabrice; Taviot-Guého, Christine; Cadars, Sylvian; Prevot, Vanessa

2016-01-01

Increasing attention has been devoted to the design of layered double hydroxide (LDH)-based hybrid materials. In this work, we demonstrate the intercalation by anion exchange process of poly(acrylic acid) (PAA) and three different hydrophilic random copolymers of acrylic acid (AA) and n -butyl acrylate (BA) with molar masses ranging from 2000 to 4200 g mol -1 synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, into LDH containing magnesium(II) and aluminium(III) intralayer cations and nitrates as counterions (MgAl-NO 3 LDH). At basic pH, the copolymer chains (macroRAFT agents) carry negative charges which allowed the establishment of electrostatic interactions with the LDH interlayer and their intercalation. The resulting hybrid macroRAFT/LDH materials displayed an expanded interlamellar domain compared to pristine MgAl-NO 3 LDH from 1.36 nm to 2.33 nm. Depending on the nature of the units involved into the macroRAFT copolymer (only AA or AA and BA), the intercalation led to monolayer or bilayer arrangements within the interlayer space. The macroRAFT intercalation and the molecular structure of the hybrid phases were further characterized by Fourier transform infrared (FTIR) and solid-state 13 C, 1 H and 27 Al nuclear magnetic resonance (NMR) spectroscopies to get a better description of the local structure.

Nano- and Macro-wear of Bio-carbo-nitrided AISI 8620 Steel Surfaces

NASA Astrophysics Data System (ADS)

Arthur, Emmanuel Kwesi; Ampaw, Edward; Zebaze Kana, M. G.; Adetunji, A. R.; Olusunle, S. O. O.; Adewoye, O. O.; Soboyejo, W. O.

2015-12-01

This paper presents the results of an experimental study of nano- and macro-scale wear in a carbo-nitrided AISI 8620 steel. Carbo-nitriding is carried out using a novel method that involves the use of dried, cyanide-containing cassava leaves, as sources of carbon and nitrogen. These are used in a pack cementation that is used to diffuse carbon and nitrogen into case layers at intermediate temperatures [673.15 K, 723.15 K, 773.15 K, and 823.15 K (400 °C, 450 °C, 500 °C, and 550 °C)]. Nano- and macro-scale wear properties are studied in the case-hardened surfaces, using a combination of nano-scratch and pin-on-disk experiments. The measured wear volumes (at both nano- and macro-length scales) are shown to increase with decreasing pack cyaniding temperature. The nano- and macro-wear resistances are also shown to be enhanced by the in situ diffusion of carbon and nitrogen from cyanide-containing bio-processed waste. The underlying wear mechanisms are also elucidated via atomic force microscopy and scanning electron microscopy observations of the wear tracks. The implications of the results are discussed for the design of hardened carbo-nitrided steel surfaces with improved wear resistance.

Design of refrigeration system using refrigerant R134a for macro compartment

NASA Astrophysics Data System (ADS)

Rani, M. F. H.; Razlan, Z. M.; Shahriman, A. B.; Yong, C. K.; Harun, A.; Hashim, M. S. M.; Faizi, M. K.; Ibrahim, I.; Kamarrudin, N. S.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

The main objective of this study is to analyse and design an optimum cooling system for macro compartment. Current product of the refrigerator is not specified for single function and not compact in size. Hence, a refrigeration system using refrigerant R134a is aimed to provide instant cooling in a macro compartment with sizing about 150 × 150 × 250 mm. The macro compartment is purposely designed to fit a bottle or drink can, which is then cooled to a desired drinking temperature of about 8°C within a period of 1 minute. The study is not only concerned with analysing of heat load of the macro compartment containing drink can, but also focused on determining suitable heat exchanger volume for both evaporator and condenser, calculating compressor displacement value and computing suitable resistance value of the expansion valve. Method of optimization is used to obtain the best solution of the problem. Mollier diagram is necessary in the process of developing the refrigeration system. Selection of blower is made properly to allow air circulation and to increase the flow rate for higher heat transfer rate. Property data are taken precisely from thermodynamic property tables. As the main four components, namely condenser, compressor, evaporator and expansion valve are fully developed, the refrigeration system is complete.

Synchronized motion control and precision positioning compensation of a 3-DOFs macro-micro parallel manipulator fully actuated by piezoelectric actuators

NASA Astrophysics Data System (ADS)

Zhang, Quan; Li, Chaodong; Zhang, Jiantao; Zhang, Xu

2017-11-01

The macro-micro combined approach, as an effective way to realize trans-scale nano-precision positioning with multi-dimensions and high velocity, plays a significant role in integrated circuit manufacturing field. A 3-degree-of-freedoms (3-DOFs) macro-micro manipulator is designed and analyzed to compromise the conflictions among the large stroke, high precision and multi-DOFs. The macro manipulator is a 3-Prismatic-Revolute-Revolute (3-PRR) structure parallel manipulator which is driven by three linear ultrasonic motors. The dynamic model and the cross-coupling error based synchronized motion controller of the 3-PRR parallel manipulator are theoretical analyzed and experimental tested. To further improve the positioning accuracy, a 3-DOFs monolithic compliant manipulator actuated by three piezoelectric stack actuators is designed. Then a multilayer BP neural network based inverse kinematic model identifier is developed to perform the positioning control. Finally, by forming the macro-micro structure, the dual stage manipulator successfully achieved the positioning task from the point (2 mm, 2 mm, 0 rad) back to the original point (0 mm, 0 mm, 0 rad) with the translation errors in X and Y directions less than ±50 nm and the rotation error around Z axis less than ±1 μrad, respectively.

Some surprising manifestations of charged particle dynamics in a magnetic field

NASA Astrophysics Data System (ADS)

Varma, Ram K.

2010-08-01

We present here some very unusual experimental results on the dynamics of charged particle in a magnetic field which cannot be comprehended in terms of the Lorentz dynamics regarded, as per the current conceptual framework, as the appropriate one for the macro-scale description. Astonishingly, these results have been shown to be manifestations of a novel macro-scale quantum structure, designated as ‘transition amplitude wave’ (TAW), riding with the guiding centre trajectory, which is generated in the latter trajectory in consequence of the scattering of the particle with a fixed scattering centre. One set of observed results is thus identified as matter wave interference effects on the macro-scale attributable to this entity. The other enigmatic observation demonstrates the detection of a curl-free magnetic vector potential on the macro-scale, which is also shown to be a consequence of the TAW embedded in the Lorentz trajectory. These enigmatic results thus point to the unravelling of a new concept of a ‘dressed’ Lorentz trajectory—dressed with the TAW—accountable for these results, as against the ‘bare’ trajectory. These results and the formalism which enables one to comprehend them have led to the emergence of a new class of phenomena which display quantum properties on the macro-scale.

Large motor units are selectively affected following a stroke.

PubMed

Lukács, M; Vécsei, L; Beniczky, S

2008-11-01

Previous studies have revealed a loss of functioning motor units in stroke patients. However, it remained unclear whether the motor units are affected randomly or in some specific pattern. We assessed whether there is a selective loss of the large (high recruitment threshold) or the small (low recruitment threshold) motor units following a stroke. Forty-five stroke patients and 40 healthy controls participated in the study. Macro-EMG was recorded from the abductor digiti minimi muscle at two levels of force output (low and high). The median macro motor unit potential (macro-MUP) amplitude on the paretic side was compared with those on the unaffected side and in the controls. In the control group and on the unaffected side, the macro-MUPs were significantly larger at the high force output than at the low one. However, on the paretic side the macro-MUPs at the high force output had the same amplitude as those recorded at the low force output. These changes correlated with the severity of the paresis. Following a stroke, there is a selective functional loss of the large, high-threshold motor units. These changes are related to the severity of the symptoms. Our findings furnish further insight into the pathophysiology of the motor deficit following a stroke.

Assessment of the Brain's Macro- and Micro-Circulatory Blood Flow Responses to CO2 via Transfer Function Analysis.

PubMed

Müller, Martin W-D; Österreich, Mareike; Müller, Andreas; Lygeros, John

2016-01-01

At present, there is no standard bedside method for assessing cerebral autoregulation (CA) with high temporal resolution. We combined the two methods most commonly used for this purpose, transcranial Doppler sonography (TCD, macro-circulation level), and near-infrared spectroscopy (NIRS, micro-circulation level), in an attempt to identify the most promising approach. In eight healthy subjects (5 women; mean age, 38 ± 10 years), CA disturbance was achieved by adding carbon dioxide (CO2) to the breathing air. We simultaneously recorded end-tidal CO2 (ETCO2), blood pressure (BP; non-invasively at the fingertip), and cerebral blood flow velocity (CBFV) in both middle cerebral arteries using TCD and determined oxygenated and deoxygenated hemoglobin levels using NIRS. For the analysis, we used transfer function calculations in the low-frequency band (0.07-0.15 Hz) to compare BP-CBFV, BP-oxygenated hemoglobin (OxHb), BP-tissue oxygenation index (TOI), CBFV-OxHb, and CBFV-TOI. ETCO2 increased from 37 ± 2 to 44 ± 3 mmHg. The CO2-induced CBFV increase significantly correlated with the OxHb increase (R (2) = 0.526, p < 0.001). Compared with baseline, the mean CO2 administration phase shift (in radians) significantly increased (p < 0.005) from -0.67 ± 0.20 to -0.51 ± 0.25 in the BP-CBFV system, and decreased from 1.21 ± 0.81 to -0.05 ± 0.91 in the CBFV-OxHb system, and from 0.94 ± 1.22 to -0.24 ± 1.0 in the CBFV-TOI system; no change was observed for BP-OxHb (0.38 ± 1.17 to 0.41 ± 1.42). Gain changed significantly only in the BP-CBFV system. The correlation between the ETCO2 change and phase change was higher in the CBFV-OxHb system [r = -0.60; 95% confidence interval (CI): -0.16, -0.84; p < 0.01] than in the BP-CBFV system (r = 0.52; 95% CI: 0.03, 0.08; p < 0.05). The transfer function characterizes the blood flow transition from macro- to micro-circulation by time delay only. The CBFV-OxHb system response with a broader phase shift distribution offers the prospect of a more detailed grading of CA responses. Whether this is of clinical relevance needs further studies in different patient populations.

Probalistic Finite Elements (PFEM) structural dynamics and fracture mechanics

NASA Technical Reports Server (NTRS)

Liu, Wing-Kam; Belytschko, Ted; Mani, A.; Besterfield, G.

1989-01-01

The purpose of this work is to develop computationally efficient methodologies for assessing the effects of randomness in loads, material properties, and other aspects of a problem by a finite element analysis. The resulting group of methods is called probabilistic finite elements (PFEM). The overall objective of this work is to develop methodologies whereby the lifetime of a component can be predicted, accounting for the variability in the material and geometry of the component, the loads, and other aspects of the environment; and the range of response expected in a particular scenario can be presented to the analyst in addition to the response itself. Emphasis has been placed on methods which are not statistical in character; that is, they do not involve Monte Carlo simulations. The reason for this choice of direction is that Monte Carlo simulations of complex nonlinear response require a tremendous amount of computation. The focus of efforts so far has been on nonlinear structural dynamics. However, in the continuation of this project, emphasis will be shifted to probabilistic fracture mechanics so that the effect of randomness in crack geometry and material properties can be studied interactively with the effect of random load and environment.

Implementation of GPU accelerated SPECT reconstruction with Monte Carlo-based scatter correction.

PubMed

Bexelius, Tobias; Sohlberg, Antti

2018-06-01

Statistical SPECT reconstruction can be very time-consuming especially when compensations for collimator and detector response, attenuation, and scatter are included in the reconstruction. This work proposes an accelerated SPECT reconstruction algorithm based on graphics processing unit (GPU) processing. Ordered subset expectation maximization (OSEM) algorithm with CT-based attenuation modelling, depth-dependent Gaussian convolution-based collimator-detector response modelling, and Monte Carlo-based scatter compensation was implemented using OpenCL. The OpenCL implementation was compared against the existing multi-threaded OSEM implementation running on a central processing unit (CPU) in terms of scatter-to-primary ratios, standardized uptake values (SUVs), and processing speed using mathematical phantoms and clinical multi-bed bone SPECT/CT studies. The difference in scatter-to-primary ratios, visual appearance, and SUVs between GPU and CPU implementations was minor. On the other hand, at its best, the GPU implementation was noticed to be 24 times faster than the multi-threaded CPU version on a normal 128 × 128 matrix size 3 bed bone SPECT/CT data set when compensations for collimator and detector response, attenuation, and scatter were included. GPU SPECT reconstructions show great promise as an every day clinical reconstruction tool.

MAGIC with formaldehyde applied to dosimetry of HDR brachytherapy source

NASA Astrophysics Data System (ADS)

Marques; T; Fernandes; J; Barbi; G; Nicolucci; P; Baffa; O

2009-05-01

The use of polymer gel dosimeters in brachytherapy can allow the determination of three-dimensional dose distributions in large volumes and with high spatial resolution if an adequate calibration process is performed. One of the major issues in these experiments is the polymer gel response dependence on dose rate when high dose rate sources are used and the doses in the vicinity of the sources are to be determinated. In this study, the response of a modified MAGIC polymer gel with formaldehyde around an Iridium-192 HDR brachytherapy source is presented. Experimental results obtained with this polymer gel were compared with ionization chamber measurements and with Monte Carlo simulation with PENELOPE. A maximum difference of 3.10% was found between gel dose measurements and Monte Carlo simulation at a radial distance of 18 mm from the source. The results obtained show that the gel's response is strongly influenced by dose rate and that a different calibration should be used for the vicinity of the source and for regions of lower dose rates. The results obtained in this study show that, provided the proper calibration is performed, MAGIC with formaldehyde can be successfully used to accurate determinate dose distributions form high dose rate brachytherapy sources.

Colloidal origin of colloform-banded textures in the Paleogene low-sulfidation Khan Krum gold deposit, SE Bulgaria

NASA Astrophysics Data System (ADS)

Marinova, Irina; Ganev, Valentin; Titorenkova, Rositsa

2014-01-01

We studied both colloform-banded macro- and micro-textures as well as the composition of electrum from the epithermal Khan Krum (or Ada Tepe) gold deposit, Bulgaria (5 Mt at 5.1 g/t Au + 2.7 g/t Ag) using optical and electron scanning microscopy, vibration spectroscopy, electron micro-probe analysis, and LA-ICP-MS. The individual textural bands differ in grain size, porosity, quartz-to-adularia ratio, and abundance of electrum, pyrite, and scattered dusty opaque micro-inclusions. The individual macro-bands have formed successively via intermittent fault dilation from episodic hydrothermal pulses, as a result of regional extension and most likely originated from colloidal solutions formed by vigorous boiling during rapid pressure drop and supersaturation with respect to amorphous silica in a closed or quasi-closed hydrothermal system. Electrum is highly concentrated in the finest quartz-adularia colloform micro-bands, which fill joints with widths up to 1-2 mm. We presume that the joints have filled in with more concentrated colloidal solutions than those in the macro-bands, most likely due to extreme boiling of fluids in open or quasi-open hydrothermal system. Electrum in the micro-bands forms transverse dendrite- and chain-like aggregates as well as oval clots along the banding, all of globular morphology. We explain these locations of electrum with reorientation of aggregated electrum globules during plastic deformation of a mixed electrum-silicate gel and in result from the consequent crystallization of silicates. At the same time, electrum is not present in pores and cracks of syneresis, which indicates that it had not been a soluble phase at the time of syneresis, rather colloidal particles. Electrum also forms dense sprinkles of globular morphology deposited in open space on the surfaces of some quartz-adularia bands, due to a condensation of gaseous phase, separated during the boiling of fluids. We found that the electrum-rich quartz-adularia micro-banding is enriched (in descending order) in Bi, Te, Cu, Fe, Pb, Au, As, U, Ba, Zn, Mg, Cr, Al, Tl, Na, K, and Th, and is slightly depleted in Si, Ti, Se, Ag, and Sb in comparison with the electrum-poor macro-bands. Ca displayed equal abundances in both macro- and micro-bands. The highest grades of electrum correspond to the highest abundances of Fe, As, Cu, Pb, Zn, Bi, and Te, which have deposited as sulfides and tellurides, thus revealing the voluminous electrum deposition in response to a significant decrease of sulfur and tellurium activities, and transport of gold and silver in the paleofluids in the form of sulfuric and telluric complexes. The epithermal Khan Krum deposit is Au dominant, Bi and Te rich, thus indicating its relationship to an igneous source.

Micro vs Macro Planning: Achieving a Balance.

ERIC Educational Resources Information Center

Slate, Judith J.; Gallagher, Jo D.

1994-01-01

The process of developing program evaluation models for Florida International University's college of education is described. One lesson learned was that a combination of macro- and microlevel planning is necessary for purposeful evaluation. A grid to aid decision making is also presented. (Author/MSE)

Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte Carlo-GEANT4 simulations for IORT mobile dedicate accelerator

NASA Astrophysics Data System (ADS)

Marrale, Maurizio; Longo, Anna; Russo, Giorgio; Casarino, Carlo; Candiano, Giuliana; Gallo, Salvatore; Carlino, Antonio; Brai, Maria

2015-09-01

In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncertainties in dosimetric determinations. The high dose per pulse could lead to an inaccuracy in dose measurements with ionization chamber, due to overestimation of ks recombination factor. Furthermore, the electron fields obtained with IORT-dedicated applicators have a wider energy spectrum and a wider angular distribution than the conventional fields, due to the presence of electrons scattered by the applicator's wall. For this reason, a dosimetry system should be characterized by a minimum dependence from the beam energy and from angle of incidence of electrons. This become particularly critical for small and bevelled applicators. All of these reasons lead to investigate the use of detectors different from the ionization chamber for measuring the OFs. Furthermore, the complete characterization of the radiation field could be accomplished also by the use of Monte Carlo simulations which allows to obtain detailed information on dose distributions. In this work we compare the output factors obtained by means of alanine dosimeters and Markus ionization chamber. The comparison is completed by the Monte Carlo calculations of OFs determined through the use of the Geant4 application "iort _ therapy" . The results are characterized by a good agreement of response of alanine pellets and Markus ionization chamber and Monte Carlo results (within about 3%) for both flat and bevelled applicators.

SU-E-T-469: A Practical Approach for the Determination of Small Field Output Factors Using Published Monte Carlo Derived Correction Factors

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

Calderon, E; Siergiej, D

2014-06-01

Purpose: Output factor determination for small fields (less than 20 mm) presents significant challenges due to ion chamber volume averaging and diode over-response. Measured output factor values between detectors are known to have large deviations as field sizes are decreased. No set standard to resolve this difference in measurement exists. We observed differences between measured output factors of up to 14% using two different detectors. Published Monte Carlo derived correction factors were used to address this challenge and decrease the output factor deviation between detectors. Methods: Output factors for Elekta's linac-based stereotactic cone system were measured using the EDGE detectormore » (Sun Nuclear) and the A16 ion chamber (Standard Imaging). Measurements conditions were 100 cm SSD (source to surface distance) and 1.5 cm depth. Output factors were first normalized to a 10.4 cm × 10.4 cm field size using a daisy-chaining technique to minimize the dependence of field size on detector response. An equation expressing the relation between published Monte Carlo correction factors as a function of field size for each detector was derived. The measured output factors were then multiplied by the calculated correction factors. EBT3 gafchromic film dosimetry was used to independently validate the corrected output factors. Results: Without correction, the deviation in output factors between the EDGE and A16 detectors ranged from 1.3 to 14.8%, depending on cone size. After applying the calculated correction factors, this deviation fell to 0 to 3.4%. Output factors determined with film agree within 3.5% of the corrected output factors. Conclusion: We present a practical approach to applying published Monte Carlo derived correction factors to measured small field output factors for the EDGE and A16 detectors. Using this method, we were able to decrease the percent deviation between both detectors from 14.8% to 3.4% agreement.« less

SENSITIVITY OF THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION MULTILAYER MODEL TO INSTRUMENT ERROR AND PARAMETERIZATION UNCERTAINTY

EPA Science Inventory

The response of the National Oceanic and Atmospheric Administration multilayer inferential dry deposition velocity model (NOAA-MLM) to error in meteorological inputs and model parameterization is reported. Monte Carlo simulations were performed to assess the uncertainty in NOA...

Comparing Three Estimation Methods for the Three-Parameter Logistic IRT Model

ERIC Educational Resources Information Center

Lamsal, Sunil

2015-01-01

Different estimation procedures have been developed for the unidimensional three-parameter item response theory (IRT) model. These techniques include the marginal maximum likelihood estimation, the fully Bayesian estimation using Markov chain Monte Carlo simulation techniques, and the Metropolis-Hastings Robbin-Monro estimation. With each…

Climate Change and Macro-Economic Cycles in Pre-Industrial Europe

PubMed Central

Pei, Qing; Zhang, David D.; Lee, Harry F.; Li, Guodong

2014-01-01

Climate change has been proven to be the ultimate cause of social crisis in pre-industrial Europe at a large scale. However, detailed analyses on climate change and macro-economic cycles in the pre-industrial era remain lacking, especially within different temporal scales. Therefore, fine-grained, paleo-climate, and economic data were employed with statistical methods to quantitatively assess the relations between climate change and agrarian economy in Europe during AD 1500 to 1800. In the study, the Butterworth filter was adopted to filter the data series into a long-term trend (low-frequency) and short-term fluctuations (high-frequency). Granger Causality Analysis was conducted to scrutinize the associations between climate change and macro-economic cycle at different frequency bands. Based on quantitative results, climate change can only show significant effects on the macro-economic cycle within the long-term. In terms of the short-term effects, society can relieve the influences from climate variations by social adaptation methods and self-adjustment mechanism. On a large spatial scale, temperature holds higher importance for the European agrarian economy than precipitation. By examining the supply-demand mechanism in the grain market, population during the study period acted as the producer in the long term, whereas as the consumer in the short term. These findings merely reflect the general interactions between climate change and macro-economic cycles at the large spatial region with a long-term study period. The findings neither illustrate individual incidents that can temporarily distort the agrarian economy nor explain some specific cases. In the study, the scale thinking in the analysis is raised as an essential methodological issue for the first time to interpret the associations between climatic impact and macro-economy in the past agrarian society within different temporal scales. PMID:24516601

Climate change and macro-economic cycles in pre-industrial europe.

PubMed

Pei, Qing; Zhang, David D; Lee, Harry F; Li, Guodong

2014-01-01

Climate change has been proven to be the ultimate cause of social crisis in pre-industrial Europe at a large scale. However, detailed analyses on climate change and macro-economic cycles in the pre-industrial era remain lacking, especially within different temporal scales. Therefore, fine-grained, paleo-climate, and economic data were employed with statistical methods to quantitatively assess the relations between climate change and agrarian economy in Europe during AD 1500 to 1800. In the study, the Butterworth filter was adopted to filter the data series into a long-term trend (low-frequency) and short-term fluctuations (high-frequency). Granger Causality Analysis was conducted to scrutinize the associations between climate change and macro-economic cycle at different frequency bands. Based on quantitative results, climate change can only show significant effects on the macro-economic cycle within the long-term. In terms of the short-term effects, society can relieve the influences from climate variations by social adaptation methods and self-adjustment mechanism. On a large spatial scale, temperature holds higher importance for the European agrarian economy than precipitation. By examining the supply-demand mechanism in the grain market, population during the study period acted as the producer in the long term, whereas as the consumer in the short term. These findings merely reflect the general interactions between climate change and macro-economic cycles at the large spatial region with a long-term study period. The findings neither illustrate individual incidents that can temporarily distort the agrarian economy nor explain some specific cases. In the study, the scale thinking in the analysis is raised as an essential methodological issue for the first time to interpret the associations between climatic impact and macro-economy in the past agrarian society within different temporal scales.

Selective ablation of rabbit atherosclerotic plaque with less thermal effect by the control of pulse structure of a quantum cascade laser in the 5.7 μm wavelength range

NASA Astrophysics Data System (ADS)

Hashimura, Keisuke; Ishii, Katsunori; Awazu, Kunio

2016-03-01

Cholesteryl esters are main components of atherosclerotic plaques and have an absorption peak at the wavelength of 5.75 μm originated from C=O stretching vibration mode of ester bond. Our group achieved the selective ablation of atherosclerotic lesions using a quantum cascade laser (QCL) in the 5.7 μm wavelength range. QCLs are relatively new types of semiconductor lasers that can emit mid-infrared range. They are sufficiently compact and considered to be useful for clinical application. However, large thermal effects were observed because the QCL worked as quasicontinuous wave (CW) lasers due to its short pulse interval. Then we tried macro pulse irradiation (irradiation of pulses at intervals) of the QCL and achieved effective ablation with less-thermal effects than conventional quasi-CW irradiation. However, lesion selectivity might be changed by changing pulse structure. Therefore, in this study, irradiation effects of the macro pulse irradiation to rabbit atherosclerotic plaque and normal vessel were compared. The macro pulse width and the macro pulse interval were set to 0.5 and 12 ms, respectively, because the thermal relaxation time of rabbit normal and atherosclerotic aortas in the oscillation wavelength of the QCL was 0.5-12 ms. As a result, cutting difference was achieved between rabbit atherosclerotic and normal aortas by the macro pulse irradiation. Therefore, macro pulse irradiation of a QCL in the 5.7 μm wavelength range is effective for reducing thermal effects and selective ablation of the atherosclerotic plaque. QCLs have the potential of realizing less-invasive laser angioplasty.

Trend in coral-algal phase shift in the Mandapam group of islands, Gulf of Mannar Marine Biosphere Reserve, India

NASA Astrophysics Data System (ADS)

Machendiranathan, M.; Senthilnathan, L.; Ranith, R.; Saravanakumar, A.; Thangaradjou, T.; Choudhry, S. B.; Sasamal, S. K.

2016-12-01

The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys were conducted with major attack of seven coral reefs diseases with high sedimentation rate, nine species of fleshy macro-algae ( Turbinaria ornata, Turbinaria conaides, Caulerpa scalpelliformis, Caulerpa racemosa, Kappaphycus alvarezii, Padina gymnosphora, Sargassum wightii, Ulva reticulata and Calurpa lentillifera) proliferation against major corals life forms (Acropora branching, Acropora digitate, Acropora tabulate, coral massive, coral submassive, coral foliose and coral encrusting). The results confirm that diseased corals most favor to macro-algae growth (15.27%) rather than the sedimentation covered corals (8.24 %). In the degradation of coral life forms, massive corals were more highly damaged (7.05%) than any other forms. Within a short period of time (May to September), coral coverage shrank to 17.4% from 21.9%, macro-algae increased 23.51% and the average sedimentation rate attained 77.52 mg cm-2d-1 with persisting coral reef diseases of 17.59%. The Pearson correlation showed that the coral cover decreased with increasing macro-algae growth, which was statistically significant ( r = -0.774, n = 100, P < 0.0005). The proliferation of the various macro-algae C. scalpellifrmis, T. ornata, C. racemosa, T. conaides, U. reticulata, S. wightii, K. alvarezii, P. gymnosphora and C. lentillifera increased with percentages of 6.0, 5.8, 5.7, 4.9, 4.2, 3.7, 2.7 and 1.9, respectively. If this trend continues, the next generation of new recruit corals will undoubtedly lead to a phase shift in Gulf of Mannar corals.

Multilevel Monte Carlo and improved timestepping methods in atmospheric dispersion modelling

NASA Astrophysics Data System (ADS)

Katsiolides, Grigoris; Müller, Eike H.; Scheichl, Robert; Shardlow, Tony; Giles, Michael B.; Thomson, David J.

2018-02-01

A common way to simulate the transport and spread of pollutants in the atmosphere is via stochastic Lagrangian dispersion models. Mathematically, these models describe turbulent transport processes with stochastic differential equations (SDEs). The computational bottleneck is the Monte Carlo algorithm, which simulates the motion of a large number of model particles in a turbulent velocity field; for each particle, a trajectory is calculated with a numerical timestepping method. Choosing an efficient numerical method is particularly important in operational emergency-response applications, such as tracking radioactive clouds from nuclear accidents or predicting the impact of volcanic ash clouds on international aviation, where accurate and timely predictions are essential. In this paper, we investigate the application of the Multilevel Monte Carlo (MLMC) method to simulate the propagation of particles in a representative one-dimensional dispersion scenario in the atmospheric boundary layer. MLMC can be shown to result in asymptotically superior computational complexity and reduced computational cost when compared to the Standard Monte Carlo (StMC) method, which is currently used in atmospheric dispersion modelling. To reduce the absolute cost of the method also in the non-asymptotic regime, it is equally important to choose the best possible numerical timestepping method on each level. To investigate this, we also compare the standard symplectic Euler method, which is used in many operational models, with two improved timestepping algorithms based on SDE splitting methods.

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

PubMed Central

da Rosa, L.A.R.; Campos, L.T.; Alves, V.G.L.; Batista, D.V.S.; Facure, A.

2010-01-01

The purpose of this study is to investigate the influence of lung heterogeneity inside a soft tissue phantom on percentage depth dose (PDD). PDD curves were obtained experimentally using LiF:Mg,Ti (TLD‐100) thermoluminescent detectors and applying Eclipse treatment planning system algorithms Batho, modified Batho (M‐Batho or BMod), equivalent TAR (E‐TAR or EQTAR), and anisotropic analytical algorithm (AAA) for a 15 MV photon beam and field sizes of 1×1,2×2,5×5, and 10×10cm2. Monte Carlo simulations were performed using the DOSRZnrc user code of EGSnrc. The experimental results agree with Monte Carlo simulations for all irradiation field sizes. Comparisons with Monte Carlo calculations show that the AAA algorithm provides the best simulations of PDD curves for all field sizes investigated. However, even this algorithm cannot accurately predict PDD values in the lung for field sizes of 1×1 and 2×2cm2. An overdosage in the lung of about 40% and 20% is calculated by the AAA algorithm close to the interface soft tissue/lung for 1×1 and 2×2cm2 field sizes, respectively. It was demonstrated that differences of 100% between Monte Carlo results and the algorithms Batho, modified Batho, and equivalent TAR responses may exist inside the lung region for the 1×1cm2 field. PACS number: 87.55.kd

Verification of unfold error estimates in the unfold operator code

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

Fehl, D.L.; Biggs, F.

Spectral unfolding is an inverse mathematical operation that attempts to obtain spectral source information from a set of response functions and data measurements. Several unfold algorithms have appeared over the past 30 years; among them is the unfold operator (UFO) code written at Sandia National Laboratories. In addition to an unfolded spectrum, the UFO code also estimates the unfold uncertainty (error) induced by estimated random uncertainties in the data. In UFO the unfold uncertainty is obtained from the error matrix. This built-in estimate has now been compared to error estimates obtained by running the code in a Monte Carlo fashionmore » with prescribed data distributions (Gaussian deviates). In the test problem studied, data were simulated from an arbitrarily chosen blackbody spectrum (10 keV) and a set of overlapping response functions. The data were assumed to have an imprecision of 5{percent} (standard deviation). One hundred random data sets were generated. The built-in estimate of unfold uncertainty agreed with the Monte Carlo estimate to within the statistical resolution of this relatively small sample size (95{percent} confidence level). A possible 10{percent} bias between the two methods was unresolved. The Monte Carlo technique is also useful in underdetermined problems, for which the error matrix method does not apply. UFO has been applied to the diagnosis of low energy x rays emitted by Z-pinch and ion-beam driven hohlraums. {copyright} {ital 1997 American Institute of Physics.}« less