Science.gov

Sample records for integrated bst-based variable

  1. Wireless Temperature Sensing with BST-Based Chipless Transponder Utilizing a Passive Phase Modulation Scheme

    NASA Astrophysics Data System (ADS)

    Mandel, Christian; Maune, Holger; Maasch, Matthias; Sazegar, Mohsen; Kubina, Bernd; Schüßler, Martin; Jakoby, Rolf

    2011-08-01

    A passive wireless temperature sensor with identification capabilities based on a phase modulation scheme is discussed in this paper. The approach presented utilizes a pulse backscatter technique based on slow wave (metamaterial) transmission lines. The focus of the work are the material engineering for the temperature-sensitive element and the integration of this element into a passive phase modulation circuit and the entire sensor tag. The approach makes use of temperature-sensitive bariumstrontium-titanate thick film capacitances. The discussed principle has been experimentally verified with a prototype.

  2. Review of Variable Generation Integration Charges

    SciTech Connect

    Porter, K.; Fink, S.; Buckley, M.; Rogers, J.; Hodge, B. M.

    2013-03-01

    The growth of wind and solar generation in the United States, and the expectation of continued growth of these technologies, dictates that the future power system will be operated in a somewhat different manner because of increased variability and uncertainty. A small number of balancing authorities have attempted to determine an 'integration cost' to account for these changes to their current operating practices. Some balancing authorities directly charge wind and solar generators for integration charges, whereas others add integration charges to projected costs of wind and solar in integrated resource plans or in competitive solicitations for generation. This report reviews the balancing authorities that have calculated variable generation integration charges and broadly compares and contrasts the methodologies they used to determine their specific integration charges. The report also profiles each balancing authority and how they derived wind and solar integration charges.

  3. Integrating Variable Renewable Energy: Challenges and Solutions

    SciTech Connect

    Bird, L.; Milligan, M.; Lew, D.

    2013-09-01

    In the U.S., a number of utilities are adopting higher penetrations of renewables, driven in part by state policies. While power systems have been designed to handle the variable nature of loads, the additional supply-side variability and uncertainty can pose new challenges for utilities and system operators. However, a variety of operational and technical solutions exist to help integrate higher penetrations of wind and solar generation. This paper explores renewable energy integration challenges and mitigation strategies that have been implemented in the U.S. and internationally, including forecasting, demand response, flexible generation, larger balancing areas or balancing area cooperation, and operational practices such as fast scheduling and dispatch.

  4. Role of Smarter Grids in Variable Renewable Resource Integration (Presentation)

    SciTech Connect

    Miller, M.

    2012-07-01

    This presentation discusses the role of smarter grids in variable renewable resource integration and references material from a forthcoming ISGAN issue paper: Smart Grid Contributions to Variable Renewable Resource Integration, co-written by the presenter and currently in review.

  5. Variables affecting the academic and social integration of nursing students.

    PubMed

    Zeitlin-Ophir, Iris; Melitz, Osnat; Miller, Rina; Podoshin, Pia; Mesh, Gustavo

    2004-07-01

    This study attempted to analyze the variables that influence the academic integration of nursing students. The theoretical model presented by Leigler was adapted to the existing conditions in a school of nursing in northern Israel. The independent variables included the student's background; amount of support received in the course of studies; extent of outside family and social commitments; satisfaction with the school's facilities and services; and level of social integration. The dependent variable was the student's level of academic integration. The findings substantiated four central hypotheses, with the study model explaining approximately 45% of the variance in the dependent variable. Academic integration is influenced by a number of variables, the most prominent of which is the social integration of the student with colleagues and educational staff. Among the background variables, country of origin was found to be significant to both social and academic integration for two main groups in the sample: Israeli-born students (both Jewish and Arab) and immigrant students.

  6. When Can Information from Ordinal Scale Variables Be Integrated?

    ERIC Educational Resources Information Center

    Kemp, Simon; Grace, Randolph C.

    2010-01-01

    Many theoretical constructs of interest to psychologists are multidimensional and derive from the integration of several input variables. We show that input variables that are measured on ordinal scales cannot be combined to produce a stable weakly ordered output variable that allows trading off the input variables. Instead a partial order is…

  7. When Can Information from Ordinal Scale Variables Be Integrated?

    ERIC Educational Resources Information Center

    Kemp, Simon; Grace, Randolph C.

    2010-01-01

    Many theoretical constructs of interest to psychologists are multidimensional and derive from the integration of several input variables. We show that input variables that are measured on ordinal scales cannot be combined to produce a stable weakly ordered output variable that allows trading off the input variables. Instead a partial order is…

  8. Integrating models that depend on variable data

    NASA Astrophysics Data System (ADS)

    Banks, A. T.; Hill, M. C.

    2016-12-01

    Models of human-Earth systems are often developed with the goal of predicting the behavior of one or more dependent variables from multiple independent variables, processes, and parameters. Often dependent variable values range over many orders of magnitude, which complicates evaluation of the fit of the dependent variable values to observations. Many metrics and optimization methods have been proposed to address dependent variable variability, with little consensus being achieved. In this work, we evaluate two such methods: log transformation (based on the dependent variable being log-normally distributed with a constant variance) and error-based weighting (based on a multi-normal distribution with variances that tend to increase as the dependent variable value increases). Error-based weighting has the advantage of encouraging model users to carefully consider data errors, such as measurement and epistemic errors, while log-transformations can be a black box for typical users. Placing the log-transformation into the statistical perspective of error-based weighting has not formerly been considered, to the best of our knowledge. To make the evaluation as clear and reproducible as possible, we use multiple linear regression (MLR). Simulations are conducted with MatLab. The example represents stream transport of nitrogen with up to eight independent variables. The single dependent variable in our example has values that range over 4 orders of magnitude. Results are applicable to any problem for which individual or multiple data types produce a large range of dependent variable values. For this problem, the log transformation produced good model fit, while some formulations of error-based weighting worked poorly. Results support previous suggestions fthat error-based weighting derived from a constant coefficient of variation overemphasizes low values and degrades model fit to high values. Applying larger weights to the high values is inconsistent with the log

  9. 75 FR 75335 - Integration of Variable Energy Resources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-02

    ... Energy Federal Energy Regulatory Commission 18 CFR Part 35 Integration of Variable Energy Resources...; ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission 18 CFR Part 35 Integration of Variable Energy Resources November 18, 2010. AGENCY: Federal Energy Regulatory Commission. ACTION: Notice of...

  10. Ubiquitous time variability of integrated stellar populations.

    PubMed

    Conroy, Charlie; van Dokkum, Pieter G; Choi, Jieun

    2015-11-26

    Long-period variable stars arise in the final stages of the asymptotic giant branch phase of stellar evolution. They have periods of up to about 1,000 days and amplitudes that can exceed a factor of three in the I-band flux. These stars pulsate predominantly in their fundamental mode, which is a function of mass and radius, and so the pulsation periods are sensitive to the age of the underlying stellar population. The overall number of long-period variables in a population is directly related to their lifetimes, which is difficult to predict from first principles because of uncertainties associated with stellar mass-loss and convective mixing. The time variability of these stars has not previously been taken into account when modelling the spectral energy distributions of galaxies. Here we construct time-dependent stellar population models that include the effects of long-period variable stars, and report the ubiquitous detection of this expected 'pixel shimmer' in the massive metal-rich galaxy M87. The pixel light curves display a variety of behaviours. The observed variation of 0.1 to 1 per cent is very well matched to the predictions of our models. The data provide a strong constraint on the properties of variable stars in an old and metal-rich stellar population, and we infer that the lifetime of long-period variables in M87 is shorter by approximately 30 per cent compared to predictions from the latest stellar evolution models.

  11. VARIABLE SPEED INTEGRATED INTELLIGENT HVAC BLOWER

    SciTech Connect

    Shixiao Wang; Herman Wiegman; Wilson Wu; John Down; Luana Iorio; Asha Devarajan; Jing Wang; Ralph Carl; Charlie Stephens; Jeannine Jones; Paul Szczesny

    2001-11-14

    This comprehensive topical report discusses the key findings in the development of a intelligent integrated blower for HVAC applications. The benefits of rearward inclined blades over that of traditional forward inclined blades is well documented and a prototype blower design is presented. A comparison of the proposed blower to that of three typical units from the industry is presented. The design of the blower housing is also addressed and the impact of size limitations on static efficiency is discussed. Issues of air flow controllability in the rearward inclined blower is addressed and a solution to this problem is proposed. Several motor design options are discussed including inside-out radial flux designs and novel axial flux designs, all are focused on the various blower needs. The control of the motor-blower and airflow through the use of a high density inverter stage and modern digital signal processor is presented. The key technical challenges of the approach are discussed. The use of the motor as a sensor in the larger heating/ventilating system is also discussed. Diagnostic results for both the motor itself and the blower system are presented.

  12. 77 FR 41481 - Integration of Variable Energy Resources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... July 13, 2012 Part II Department of Energy Federal Energy Regulatory Commission 18 CFR Part 35 Integration of Variable Energy Resources; Final Rule #0;#0;Federal Register / Vol. 77 , No. 135 / Friday, July 13, 2012 / Rules and Regulations#0;#0; ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission...

  13. How to Integrate Variable Power Source into a Power Grid

    NASA Astrophysics Data System (ADS)

    Asano, Hiroshi

    This paper discusses how to integrate variable power source such as wind power and photovoltaic generation into a power grid. The intermittent renewable generation is expected to penetrate for less carbon intensive power supply system, but it causes voltage control problem in the distribution system, and supply-demand imbalance problem in a whole power system. Cooperative control of customers' energy storage equipment such as water heater with storage tank for reducing inverse power flow from the roof-top PV system, the operation technique using a battery system and the solar radiation forecast for stabilizing output of variable generation, smart charging of plug-in hybrid electric vehicles for load frequency control (LFC), and other methods to integrate variable power source with improving social benefits are surveyed.

  14. Quantum integrals of motion for variable quadratic Hamiltonians

    SciTech Connect

    Cordero-Soto, Ricardo; Suazo, Erwin; Suslov, Sergei K.

    2010-09-15

    We construct integrals of motion for several models of the quantum damped oscillators in a framework of a general approach to the time-dependent Schroedinger equation with variable quadratic Hamiltonians. An extension of the Lewis-Riesenfeld dynamical invariant is given. The time-evolution of the expectation values of the energy-related positive operators is determined for the oscillators under consideration. A proof of uniqueness of the corresponding Cauchy initial value problem is discussed as an application.

  15. Integration of Variable Generation and Cost-Causation (Fact Sheet)

    SciTech Connect

    Not Available

    2012-09-01

    Variable renewable energy generation sources, such as wind and solar energy, provide benefits such as reduced environmental impact, zero fuel consumption, and low and stable costs. Advances in both technologies can reduce capital costs and provide significant control capabilities. However, their variability and uncertainty - which change with weather conditions, time of day, and season - can cause an increase in power system operating costs compared to a fully controllable power plant. Although a number of studies have assessed integration costs, calculating them correctly is challenging because it is difficult to accurately develop a baseline scenario without variable generation that properly accounts for the energy value. It is also difficult to appropriately allocate costs given the complex, nonlinear interactions between resources and loads.

  16. Time series Analysis of Integrateds Building System Variables

    NASA Astrophysics Data System (ADS)

    Georgiev, Tz.; Jonkov, T.; Yonchev, E.

    2010-10-01

    This article deals with time series analysis of indoor and outdoor variables of the integrated building system. The kernel of these systems is heating, ventilation and air conditioning (HVAC) problems. Important outdoor and indoor variables are: air temperature, global and diffuse radiations, wind speed and direction, temperature, relative humidity, mean radiant temperature, and so on. The aim of this article is TO select the structure and investigation of a linear auto—regressive (AR) and auto—regressive with external inputs (ARX) models. The investigation of obtained models is based on real—live data. All researches are derived in MATLAB environment. The further research will focus on synthesis of robust energy saving control algorithms.

  17. Local Discontinuous Galerkin Approximations And Variable Step Size, Variable Order Time Integration For Richards' Equation

    NASA Astrophysics Data System (ADS)

    Li, H.; Farthing, M. W.; Dawson, C. N.; Miller, C. T.

    2004-12-01

    Numerical simulation of Richards' equation continues to be difficult. It is highly nonlinear under common constitutive relations and exhibits sharp fronts in both the pressure head and volume fraction for many problems of interest. For a number of multiphase flow problems, the use of variable order and variable step size temporal discretizations has shown some advantages. However, the spatial discretizations commonly used for variably saturated flow are dominated by nonadaptive, low-order finite difference and finite element methods. Discontinuous Galerkin (DG) finite element methods have received significant attention in a number of fields for hyperbolic PDE's and, more recently, for elliptic and parabolic problems. DG approaches like the local discontinuous Galerkin (LDG) method are appealing for modeling subsurface flow since they can lead to velocity fields that are locally mass-conservative without the need for auxiliary variables or alternative meshes. DG discretizations are also inherently local and so better-suited for unstructured meshes and h-p adaption strategies than traditional methods. While some work has been done recently for multiphase subsurface flow, there are a range of issues related to the performance of DG methods for highly nonlinear parabolic problems like Richards' equation that have not been investigated fully. In this work, we consider the combination of higher order adaptive time integration with an LDG spatial discretization for Richards' equation. We compare this approach to standard low-order methods for a series of test problems and consider a number of issues including the methods' relative accuracy and computational efficiency.

  18. Planning for Variable Generation Integration through Balancing Authorities Consolidation

    SciTech Connect

    Diao, Ruisheng; Samaan, Nader A.; Makarov, Yuri V.; Hafen, Ryan P.; Ma, Jian

    2012-11-10

    As more and more variable generation is integrated into power grids, many challenges and concerns arise for an individual balancing authority (BA) to balance the system with limited resources. Consolidating balancing authorities provides a promising method to mitigate these problems by enabling the sharing of resources through operating different BAs as a single BA. The diversity in load and renewable generation over a wide area can be effectively leveraged, which makes it possible to achieve significant savings in balancing requirements. This paper develops a detailed procedure to compute savings in load following and regulation service requirements due to BAs consolidation. It proposes several evaluation metrics for demonstrating the benefits of BA consolidation. Several study scenarios are designed for a set of BAs in the western United States to test the proposed procedure. Results have shown significant savings in the capacity, ramp rate, and energy of balancing service requirements. Important factors affecting the savings, such as forecast accuracy and cross correlation between forecast errors, are also discussed.

  19. Cognitive Intraindividual Variability and White Matter Integrity in Aging

    PubMed Central

    2013-01-01

    The intraindividual variability (IIV) of cognitive performance has been shown to increase with aging. While brain research has generally focused on mean performance, little is known about neural correlates of cognitive IIV. Nevertheless, some studies suggest that IIV relates more strongly than mean level of performance to the quality of white matter (WM). Our study aims to explore the relation between WM integrity and cognitive IIV by combining functional (fMRI) and structural (diffusion tensor imaging, DTI) imaging. Twelve young adults (aged 18–30 years) and thirteen older adults (61–82 years) underwent a battery of neuropsychological tasks, along with fMRI and DTI imaging. Their behavioral data were analyzed and correlated with the imaging data at WM regions of interest defined on the basis of (1) the fMRI-activated areas and (2) the Johns Hopkins University (JHU) WM tractography atlas. For both methods, fractional anisotropy, along with the mean, radial, and axial diffusivity parameters, was computed. In accord with previous studies, our results showed that the DTI parameters were more related to IIV than to mean performance. Results also indicated that age differences in the DTI parameters were more pronounced in the regions activated primarily by young adults during a choice reaction-time task than in those also activated in older adults. PMID:24174913

  20. Cost-Causation and Integration Cost Analysis for Variable Generation

    SciTech Connect

    Milligan, M.; Ela, E.; Hodge, B. M.; Kirby, B.; Lew, D.; Clark, C.; DeCesaro, J.; Lynn, K.

    2011-06-01

    This report examines how wind and solar integration studies have evolved, what analysis techniques work, what common mistakes are still made, what improvements are likely to be made in the near future, and why calculating integration costs is such a difficult problem and should be undertaken carefully, if at all.

  1. 78 FR 72878 - Integration of Variable Energy Resources; Notice Of Filing Procedures for Order No. 764...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Integration of Variable Energy Resources; Notice Of Filing Procedures for... to compliance obligations in Integration of Variable Energy Resources, Order No. 764, FERC Stats...

  2. Variable Structure PID Control to Prevent Integrator Windup

    NASA Technical Reports Server (NTRS)

    Hall, C. E.; Hodel, A. S.; Hung, J. Y.

    1999-01-01

    PID controllers are frequently used to control systems requiring zero steady-state error while maintaining requirements for settling time and robustness (gain/phase margins). PID controllers suffer significant loss of performance due to short-term integrator wind-up when used in systems with actuator saturation. We examine several existing and proposed methods for the prevention of integrator wind-up in both continuous and discrete time implementations.

  3. Mindfulness and integrative self-knowledge: relationships with health-related variables.

    PubMed

    Ghasemipour, Yadollah; Robinson, Julie Ann; Ghorbani, Nima

    2013-01-01

    This study examined how mindfulness and integrative self-knowledge were related to health-related issues. Men in general population (n = 103) and coronary heart disease samples (n = 101) completed the Mindful Attention Awareness Scale, the Integrative Self-knowledge Scale, the Type 2 subscale of the Interpersonal Reactions Inventory, the Perceived Stress Scale, and the Anxiety and Depression Scales. In both samples, there was a moderate positive correlation between mindfulness and integrative self-knowledge and they were negatively correlated with all health-related variables. However, only integrative self-knowledge explained independent variance in health-related variables. Specifically, in both samples, the relationship between mindfulness and health-related variables was mediated by integrative self-knowledge. Mindfulness and integrative self-knowledge are related domains of self-awareness that are associated with a range of health-related variables. These relationships are robust across samples drawn from general population and patients with coronary heart disease. The finding that integrative self-knowledge explained additional variance in the health-related variables after the contribution of mindfulness had been accounted for suggests that reflective self-awareness in integrative self-knowledge may make a unique contribution to the explanation of individual differences in health variables.

  4. Bionic intraocular lens with variable focus and integrated structure

    NASA Astrophysics Data System (ADS)

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei; Xiang, Ke

    2015-10-01

    This paper proposes a bionic accommodating intraocular lens (IOL) for ophthalmic surgery. The designed lens has a solid-liquid mixed integrated structure, which mainly consists of a support ring, elastic membrane, rigid lens, and optical liquid. The lens focus can be adjusted through the deformation of the lens front surface when compressed. The integrated structure of the IOL is presented, as well as a detailed description of the lens materials and fabrication process. Images under different radial pressures are captured, and the lens deformation process, accommodating range, density, and optical property are analyzed. The designed lens achieves a 14.6 D accommodating range under a radial pressure of 51.4 mN and a 0.24 mm alteration of the lens outer radius. The deformation property of the lens matches well with the characteristic of the eye and shows the potential to help patients fully recover their vision accommodation ability after the cataract surgery.

  5. A new explicit variable time-integration self-starting methodology for computational structural dynamics

    NASA Technical Reports Server (NTRS)

    Tamma, Kumar K.; D'Costa, Joseph F.

    1992-01-01

    A new explicit variable time-integration methodology and architecture which possesses self-starting attributes, eliminates the need to involve acceleration computations, and which has improved accuracy characteristics in comparison to the traditional central-difference-type formulations customarily advocated is described for applicability to computational structural dynamics. To sharpen the focus of the present study, an explicit variable time-integration architecture which is relatively simple, yet effective, is described. Unlike variable explicit time-integration formulations adopted in the past, the present self-starting variable time-integration architecture and implementation aspects facilitate a simplified representation and a straightforward and effective approach for combining finite element meshes requiring different time steps in a single analysis. Numerical test cases are provided which demonstrate the applicability of the proposed formulations.

  6. Variable Step-Size Selection Methods for Implicit Integration Schemes

    DTIC Science & Technology

    2005-10-01

    for ρk numerically. 23 4 Examples In this section we explore this variable step-size selection method for two problems, the Lotka - Volterra model and...the Kepler problem. 4.1 The Lotka - Volterra Model For this example we consider the Lotka - Volterra model of a simple predator- prey system from...problems. Consider this variation to the Lotka - Volterra problem:   u̇ v̇   =   u2v(v − 2) v2u(1− u)   = f(u, v); t ∈ [0, 50

  7. Some Problems of Movement of Bodies with Variable Masses and Cases of Their Integration

    NASA Astrophysics Data System (ADS)

    Mammadli, A. H.

    2009-12-01

    Problems of movement of bodies with variable masses within the framework of the two-body problem are considered. It is shown, that under certain conditions by the method of spatial-time transformation the differential equations of movement with variable coefficients suppose autonomization, i.e. are transformed to the differential equations with constant coefficients, integrated in quadrature. The analogue of the Jacobi integral is found, surfaces of zero velocity and possible regions of motion are determined. As an example the problem of the motion of a star with a variable mass inside a globular cluster with a variable mass is considered. It has turned out, that the solution of differential equations in new variables represents elliptical epicycloids, and in initial variables it is a very complex trajectory. At the research of motion in the gravitating and resisting medium it is shown, that in the law change of Jeans mass the change of a body mass sign is admissible.

  8. Investigating Variables Predicting Turkish Pre-service Teachers' Integration of ICT into Teaching Practices

    ERIC Educational Resources Information Center

    Aslan, Aydin; Zhu, Chang

    2017-01-01

    Pre-service teachers need to acquire information and communications technology (ICT) competency in order to integrate ICT into their teaching practices. This research was conducted to investigate to what extent ICT-related variables--such as perceived ICT competence, perceived competence in ICT integration, attitudes toward ICT, anxiety around ICT…

  9. Investigating Variables Predicting Turkish Pre-service Teachers' Integration of ICT into Teaching Practices

    ERIC Educational Resources Information Center

    Aslan, Aydin; Zhu, Chang

    2017-01-01

    Pre-service teachers need to acquire information and communications technology (ICT) competency in order to integrate ICT into their teaching practices. This research was conducted to investigate to what extent ICT-related variables--such as perceived ICT competence, perceived competence in ICT integration, attitudes toward ICT, anxiety around ICT…

  10. Multi-symplectic variational integrators for nonlinear Schrödinger equations with variable coefficients

    NASA Astrophysics Data System (ADS)

    Cui-Cui, Liao; Jin-Chao, Cui; Jiu-Zhen, Liang; Xiao-Hua, Ding

    2016-01-01

    In this paper, we propose a variational integrator for nonlinear Schrödinger equations with variable coefficients. It is shown that our variational integrator is naturally multi-symplectic. The discrete multi-symplectic structure of the integrator is presented by a multi-symplectic form formula that can be derived from the discrete Lagrangian boundary function. As two examples of nonlinear Schrödinger equations with variable coefficients, cubic nonlinear Schrödinger equations and Gross-Pitaevskii equations are extensively studied by the proposed integrator. Our numerical simulations demonstrate that the integrator is capable of preserving the mass, momentum, and energy conservation during time evolutions. Convergence tests are presented to verify that our integrator has second-order accuracy both in time and space. Project supported by the National Natural Science Foundation of China (Grant No. 11401259) and the Fundamental Research Funds for the Central Universities, China (Grant No. JUSRR11407).

  11. On the Variability of the Solar Integral Radiation Constituents

    NASA Technical Reports Server (NTRS)

    Nikolsky, G. A.

    1990-01-01

    The results of spectral analysis of series of observations of the equatorial and polar diameters, as well as of series of satellite observations of the S sub O variations during 1975 to 1987 presented in papers by Laclare (1987), Delache (1988) and Delache et al. (1988) confirm with confidence the presence of an 11-year modulation in the Sun's radiation and diameter, and consequently, in the effective temperature of the photosphere. The same conclusion has been drawn with regard to the 1000th and 320th daily periodicities. In combination with the results of other research, several obvious conclusions can be drawn from the data presented. The 76-year variation in the period from 1967 to 1987 is not revealed in the data of observations; the data of the middle series will doubtless be made more precise after the facsimile from the initial information is obtained. The basic and comparable contributions to the radius variability yield the 11- and 22-year variations. The presence can easily be seen of harmonics with periods of 2 and 4 years; the 4-year period is revealed up to 1979 only, and the 2-year one, after 1980 only. This is possibly due to the combined contribution of the 11- and 22-year variations (to be more precise, 10.8 and 21.2 years) forming a certain mean 16-year periodicity. In this case, the 4- and 2-year variations can be regarded as the 4th and 8th harmonics of such a mean variation. Measurements of the horizontal diameter made at Greenwich Observatory have not lost their significance for the analysis of phenomena on the Sun, since they contain data having precision characteristics conforming to the level of the latest ground-based diameter measurements.

  12. Integrating Variable Renewable Energy in Electric Power Markets: Best Practices from International Experience (Fact Sheet)

    SciTech Connect

    Not Available

    2014-10-01

    Many countries--reflecting very different geographies, markets, and power systems--are successfully managing high levels of variable renewable energy (RE) on the grid. Australia (South Australia), Denmark, Germany, Ireland, Spain, and the United States (Colorado and Texas), for example, have effectively integrated variable RE utilizing diverse approaches. Analysis of the results from these case studies reveals a wide range of mechanisms that can be used to accommodate high penetrations of variable RE (e.g., from new market designs to centralized planning). Nevertheless, the myriad approaches collectively suggest that governments can best enable variable RE grid integration by implementing best practices in five areas of intervention: lead public engagement, particularly for new transmission; coordinate and integrate planning; develop rules for market evolution that enable system flexibility; expand access to diverse resources and geographic footprint of operations; and improve system operations.

  13. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2014-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  14. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  15. Integrating Variable Renewable Energy into the Grid: Key Issues, Greening the Grid (Spanish Version)

    SciTech Connect

    2016-04-01

    This is the Spanish version of 'Greening the Grid - Integrating Variable Renewable Energy into the Grid: Key Issues'. To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost-effectiveness of incorporating VRE into the power system while maintaining or increasing system stability and reliability. When considering grid integration, policy makers, regulators, and system operators consider a variety of issues, which can be organized into four broad topics: New Renewable Energy Generation, New Transmission, Increased System Flexibility, and Planning for a High RE Future.

  16. Design of a multivariable integrated control for a supersonic propulsion system. [variable stream control engine

    NASA Technical Reports Server (NTRS)

    Beattie, E. C.

    1980-01-01

    An inlet/engine/nozzle integrated control mode for the propulsion system of an advanced supersonic commercial aircraft was studied. Results show that integration of these control functions can result in both operational and performance benefits for the propulsion system. For example, this integrated control mode may make it possible to minimize the use of inlet bypass doors for shock position control. This may be of benefit to the aircraft as a result of minimizing: (1) bypass bleed drag effects; (2) perturbations to the aircraft resulting from the side thrust effect of the bypass bleeds; and (3) potential unstarts of the inlet. A conceptual integrated control mode was developed which makes use of many cross coupling paths between inlet and engine control variables and inlet and engine sensed variables. A multivariable control design technique based upon linear quadratic regulator theory was applied to designing the feedback gains for this control to allow a simulation evaluation of the benefits of the integrated control mode.

  17. A New Integrated Weighted Model in SNOW-V10: Verification of Categorical Variables

    NASA Astrophysics Data System (ADS)

    Huang, Laura X.; Isaac, George A.; Sheng, Grant

    2014-01-01

    This paper presents the verification results for nowcasts of seven categorical variables from an integrated weighted model (INTW) and the underlying numerical weather prediction (NWP) models. Nowcasting, or short range forecasting (0-6 h), over complex terrain with sufficient accuracy is highly desirable but a very challenging task. A weighting, evaluation, bias correction and integration system (WEBIS) for generating nowcasts by integrating NWP forecasts and high frequency observations was used during the Vancouver 2010 Olympic and Paralympic Winter Games as part of the Science of Nowcasting Olympic Weather for Vancouver 2010 (SNOW-V10) project. Forecast data from Canadian high-resolution deterministic NWP system with three nested grids (at 15-, 2.5- and 1-km horizontal grid-spacing) were selected as background gridded data for generating the integrated nowcasts. Seven forecast variables of temperature, relative humidity, wind speed, wind gust, visibility, ceiling and precipitation rate are treated as categorical variables for verifying the integrated weighted forecasts. By analyzing the verification of forecasts from INTW and the NWP models among 15 sites, the integrated weighted model was found to produce more accurate forecasts for the 7 selected forecast variables, regardless of location. This is based on the multi-categorical Heidke skill scores for the test period 12 February to 21 March 2010.

  18. Identifying Discriminating Variables between Teachers Who Fully Integrate Computers and Teachers with Limited Integration

    ERIC Educational Resources Information Center

    Mueller, Julie; Wood, Eileen; Willoughby, Teena; Ross, Craig; Specht, Jacqueline

    2008-01-01

    Given the prevalence of computers in education today, it is critical to understand teachers' perspectives regarding computer integration in their classrooms. The current study surveyed a random sample of a heterogeneous group of 185 elementary and 204 secondary teachers in order to provide a comprehensive summary of teacher characteristics and…

  19. Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant

    DOEpatents

    Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

    2013-09-17

    System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

  20. 75 FR 11164 - Integration of Variable Energy Resources; Notice Extending Comment Period

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-10

    ... Energy Regulatory Commission Integration of Variable Energy Resources; Notice Extending Comment Period... extension of the period in which to file comments in response to the Commission's January 21, 2010 Notice of Inquiry (NOI) in this proceeding.\\1\\ EEI requests a fourteen-day extension of the comment period, which...

  1. CHARACTERIZATION OF DATA VARIABILITY AND UNCERTAINTY: HEALTH EFFECTS ASSESSMENTS IN THE INTEGRATED RISK INFORMATION SYSTEM (IRIS)

    EPA Science Inventory

    In response to a Congressional directive contained in HR 106-379 regarding EPA's appropriations for FY2000, EPA has undertaken an evaluation of the characterization of data variability and uncertainty in its Integrated Risk Information System (IRIS) health effects information dat...

  2. CHARACTERIZATION OF DATA VARIABILITY AND UNCERTAINTY: HEALTH EFFECTS ASSESSMENTS IN THE INTEGRATED RISK INFORMATION SYSTEM (IRIS)

    EPA Science Inventory

    In response to a Congressional directive contained in HR 106-379 regarding EPA's appropriations for FY2000, EPA has undertaken an evaluation of the characterization of data variability and uncertainty in its Integrated Risk Information System (IRIS) health effects information dat...

  3. Integration of aerial imaging and variable-rate technology for site-specific aerial herbicide application

    USDA-ARS?s Scientific Manuscript database

    As remote sensing and variable rate technology are becoming more available for aerial applicators, practical methodologies on effective integration of these technologies are needed for site-specific aerial applications of crop production and protection materials. The objectives of this study were to...

  4. Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study

    SciTech Connect

    Cappers, Peter; Mills, Andrew; Goldman, Charles; Wiser, Ryan; Eto, Joseph H.

    2011-09-10

    This scoping study focuses on the policy issues inherent in the claims made by some Smart Grid proponents that the demand response potential of mass market customers which is enabled by widespread implementation of Advanced Metering Infrastructure (AMI) through the Smart Grid could be the “silver bullet” for mitigating variable generation integration issues. In terms of approach, we will: identify key issues associated with integrating large amounts of variable generation into the bulk power system; identify demand response opportunities made more readily available to mass market customers through widespread deployment of AMI systems and how they can affect the bulk power system; assess the extent to which these mass market Demand Response (DR) opportunities can mitigate Variable Generation (VG) integration issues in the near-term and what electricity market structures and regulatory practices could be changed to further expand the ability for DR to mitigate VG integration issues over the long term; and provide a qualitative comparison of DR and other approaches to mitigate VG integration issues.

  5. Integrating Variable Renewable Energy into the Grid: Key Issues, Greening the Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin

    2015-05-01

    To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost-effectiveness of incorporating VRE into the power system while maintaining or increasing system stability and reliability. When considering grid integration, policy makers, regulators, and system operators consider a variety of issues, which can be organized into four broad topics: New Renewable Energy Generation, New Transmission, Increased System Flexibility, Planning for a High RE Future.

  6. A New Integrated Weighted Model in SNOW-V10: Verification of Continuous Variables

    NASA Astrophysics Data System (ADS)

    Huang, Laura X.; Isaac, George A.; Sheng, Grant

    2014-01-01

    This paper presents the verification results of nowcasts of four continuous variables generated from an integrated weighted model and underlying Numerical Weather Prediction (NWP) models. Real-time monitoring of fast changing weather conditions and the provision of short term forecasts, or nowcasts, in complex terrain within coastal regions is challenging to do with sufficient accuracy. A recently developed weighting, evaluation, bias correction and integration system was used in the Science of Nowcasting Olympic Weather for Vancouver 2010 project to generate integrated weighted forecasts (INTW) out to 6 h. INTW forecasts were generated with in situ observation data and background gridded forecasting data from Canadian high-resolution deterministic NWP system with three nested grids at 15-, 2.5- and 1-km horizontal grid-spacing configurations. In this paper, the four variables of temperature, relative humidity, wind speed and wind gust are treated as continuous variables for verifying the INTW forecasts. Fifteen sites were selected for the comparison of the model performances. The results of the study show that integrating surface observation data with the NWP forecasts produce better statistical scores than using either the NWP forecasts or an objective analysis of observed data alone. Overall, integrated observation and NWP forecasts improved forecast accuracy for the four continuous variables. The mean absolute errors from the INTW forecasts for the entire test period (12 February to 21 March 2010) are smaller than those from NWP forecasts with three configurations. The INTW is the best and most consistent performer among all models regardless of location and variable analyzed.

  7. An adolescent weight-loss program integrating family variables reduces energy intake.

    PubMed

    Kitzman-Ulrich, Heather; Hampson, Robert; Wilson, Dawn K; Presnell, Katherine; Brown, Alan; O'Boyle, Mary

    2009-03-01

    Family variables such as cohesion and nurturance have been associated with adolescent weight-related health behaviors. Integrating family variables that improve family functioning into traditional weight-loss programs can provide health-related benefits. The current study evaluated a family-based psychoeducational and behavioral skill-building weight-loss program for adolescent girls that integrated Family Systems and Social Cognitive Theories. Forty-two overweight (> or = 95th percentile) female adolescent participants and parents participated in a 16-week randomized controlled trial comparing three groups: multifamily therapy plus psychoeducation (n=15), psychoeducation-only (n=16), or wait list (control; n=11) group. Body mass index, energy intake, and family measures were assessed at baseline and posttreatment. Adolescents in the psychoeducation-only group demonstrated a greater decrease in energy intake compared to the multifamily therapy plus psychoeducation and control groups (P<0.01). Positive changes in family nurturance were associated with lower levels of adolescent energy intake (P<0.05). No significant effects were found for body mass index. Results provide preliminary support for a psychoeducational program that integrates family variables to reduce energy intake in overweight adolescent girls. Results indicate that nurturance can be an important family variable to target in future adolescent weight-loss and dietary programs.

  8. [Evaluation of the quality of the human spermatozoon: comparison between spermatic DNA integrity and semen variables].

    PubMed

    Cruz, Ibis; Colmenares, Melisa; Berrueta-Carrillo, Leidith; Gomez-Perez, Roald; Montes, Henry; Berrueta, Lisbeth; Salmen, Siham; Osuna, Jesús Alfonso

    2010-03-01

    Semen analysis does not have an absolute predictive value on fertility, however it is a reflection of male fertility potential, which is related to its spermatozoa quality and other semen variables. Great variability in human semen parameters has been demonstrated within a single individual, an observation that could explain why a male with low semen quality can successfully fertilize an egg. Although conventional semen analysis, such as sperm concentration, motility and morphology, provide important information about the clinical status of male fertility, new procedures to predict the sperm functional capability have been developed in the last decade, such as analysis of nuclear DNA integrity, which have improved considerably the clinical diagnosis of male infertility, and increased the knowledge about spermatozoa function. DNA fragmentation consist in interruptions, both in single and double DNA strains, that frequently occur in sperm samples from infertile patients. We have conducted a clinical study in semen samples from patients who have attended the Andrology laboratory of the University of Los Andes, between March 2007 and March 2009. The aim of this study was to compare sperm DNA integrity, analyzed by flow cytometry, with traditional semen parameters. Our results show remarkable correlations between conventional human semen variables and sperm chromatin integrity, contributing to asses an integral evaluation of sperm quality allowing the analysis of its fertilizing potential in clinical studies.

  9. The performance of integrated transconductance amplifiers as variable current sources for bio-electric impedance measurements.

    PubMed

    Smith, D N

    1992-01-01

    Multiple applied current impedance measurement systems require numbers of current sources which operate simultaneously at the same frequency and within the same phase but at variable amplitudes. Investigations into the performance of some integrated operational transconductance amplifiers as variable current sources are described. Measurements of breakthrough, non-linearity and common-mode output levels for LM13600, NE5517 and CA3280 were carried out. The effects of such errors on the overall performance and stability of multiple current systems when driving floating loads are considered.

  10. Variable Temporal Integration of Stimulus Patterns in the Mouse Barrel Cortex.

    PubMed

    Pitas, Anna; Albarracín, Ana Lía; Molano-Mazón, Manuel; Maravall, Miguel

    2016-02-01

    Making sense of the world requires distinguishing temporal patterns and sequences lasting hundreds of milliseconds or more. How cortical circuits integrate over time to represent specific sensory sequences remains elusive. Here we assessed whether neurons in the barrel cortex (BC) integrate information about temporal patterns of whisker movements. We performed cell-attached recordings in anesthetized mice while delivering whisker deflections at variable intervals and compared the information carried by neurons about the latest interstimulus interval (reflecting sensitivity to instantaneous frequency) and earlier intervals (reflecting integration over timescales up to several hundred milliseconds). Neurons carried more information about the latest interval than earlier ones. The amount of temporal integration varied with neuronal responsiveness and with the cortical depth of the recording site, that is, with laminar location. A subset of neurons in the upper layers displayed the strongest integration. Highly responsive neurons in the deeper layers encoded the latest interval but integrated particularly weakly. Under these conditions, BC neurons act primarily as encoders of current stimulation parameters; however, our results suggest that temporal integration over hundreds of milliseconds can emerge in some neurons within BC.

  11. Integrable equations of the infinite nonlinear Schrödinger equation hierarchy with time variable coefficients.

    PubMed

    Kedziora, D J; Ankiewicz, A; Chowdury, A; Akhmediev, N

    2015-10-01

    We present an infinite nonlinear Schrödinger equation hierarchy of integrable equations, together with the recurrence relations defining it. To demonstrate integrability, we present the Lax pairs for the whole hierarchy, specify its Darboux transformations and provide several examples of solutions. These resulting wavefunctions are given in exact analytical form. We then show that the Lax pair and Darboux transformation formalisms still apply in this scheme when the coefficients in the hierarchy depend on the propagation variable (e.g., time). This extension thus allows for the construction of complicated solutions within a greatly diversified domain of generalised nonlinear systems.

  12. The Effects of Basic Gymnastics Training Integrated with Physical Education Courses on Selected Motor Performance Variables

    ERIC Educational Resources Information Center

    Alpkaya, Ufuk

    2013-01-01

    The purpose of this study is to determine the influence of gymnastics training integrated with physical education courses on selected motor performance variables in seven year old girls. Subjects were divided into two groups: (1) control group (N=15, X=7.56 plus or minus 0.46 year old); (2) gymnastics group (N=16, X=7.60 plus or minus 0.50 year…

  13. The Effects of Basic Gymnastics Training Integrated with Physical Education Courses on Selected Motor Performance Variables

    ERIC Educational Resources Information Center

    Alpkaya, Ufuk

    2013-01-01

    The purpose of this study is to determine the influence of gymnastics training integrated with physical education courses on selected motor performance variables in seven year old girls. Subjects were divided into two groups: (1) control group (N=15, X=7.56 plus or minus 0.46 year old); (2) gymnastics group (N=16, X=7.60 plus or minus 0.50 year…

  14. Shape Changing and Accelerating Solitons in the Integrable Variable Mass Sine-Gordon Model

    SciTech Connect

    Kundu, Anjan

    2007-10-12

    The sine-Gordon model with a variable mass (VMSG) appears in many physical systems, ranging from the current through a nonuniform Josephson junction to DNA-promoter dynamics. Such models are usually nonintegrable with solutions found numerically or perturbatively. We construct a class of VMSG models, integrable at both the classical and the quantum levels with exact soliton solutions, which can accelerate and change their shape, width, and amplitude simulating realistic inhomogeneous systems at certain limits.

  15. VizieR Online Data Catalog: Variable sources detected by INTEGRAL (Telezhinsky+, 2010)

    NASA Astrophysics Data System (ADS)

    Telezhinsky, I.; Eckert, D.; Savchenko, V.; Neronov, A.; Produit, N.; Courvoisier, T. J.-L.

    2010-08-01

    The catalog gives the values of fractional variability, the flux, and the corresponding 2σ errors of the sources from the INTEGRAL Reference Catalog (Cat. J/A+A/411/L59) version 30. The data is given for 3 energy bands: 20-40, 40-100, and 100-200keV. The exposure times of the sources are given for each energy band only if the source was detected in the given band. The last column gives the source type according to the reference catalog. If the source is localized in more then one map then the weighted mean values of the flux and variability are given. The sources active during specific time periods and not detected at the total variability map are indicated with "b" letter in the Flag column. The sources detected only at the total variability map are indicated with "i" letter respectively. Letter "g" indicates that the source was affected by the "ghost". The numbers after the variability columns show the time period map where the source is visible and asterix means that the source is not detected at the respective significance map. Lower limit for fractional variability is given in such a case. (1 data file).

  16. Multi-taxa integrated landscape genetics for zoonotic infectious diseases: deciphering variables influencing disease emergence.

    PubMed

    Leo, Sarah S T; Gonzalez, Andrew; Millien, Virginie

    2016-05-01

    Zoonotic disease transmission systems involve sets of species interacting with each other and their environment. This complexity impedes development of disease monitoring and control programs that require reliable identification of spatial and biotic variables and mechanisms facilitating disease emergence. To overcome this difficulty, we propose a framework that simultaneously examines all species involved in disease emergence by integrating concepts and methods from population genetics, landscape ecology, and spatial statistics. Multi-taxa integrated landscape genetics (MTILG) can reveal how interspecific interactions and landscape variables influence disease emergence patterns. We test the potential of our MTILG-based framework by modelling the emergence of a disease system across multiple species dispersal, interspecific interaction, and landscape scenarios. Our simulations showed that both interspecific-dependent dispersal patterns and landscape characteristics significantly influenced disease spread. Using our framework, we were able to detect statistically similar inter-population genetic differences and highly correlated spatial genetic patterns that imply species-dependent dispersal. Additionally, species that were assigned coupled-dispersal patterns were affected to the same degree by similar landscape variables. This study underlines the importance of an integrated approach to investigating emergence of disease systems. MTILG is a robust approach for such studies and can identify potential avenues for targeted disease management strategies.

  17. Integrating Variable Renewable Energy in Electric Power Markets: Best Practices from International Experience

    SciTech Connect

    Cochran, J.; Bird, L.; Heeter, J.; Arent, D. A.

    2012-04-01

    Many countries -- reflecting very different geographies, markets, and power systems -- are successfully managing high levels of variable renewable energy on the electric grid, including that from wind and solar energy. This study documents the diverse approaches to effective integration of variable renewable energy among six countries -- Australia (South Australia), Denmark, Germany, Ireland, Spain, and the United States (Western region-Colorado and Texas)-- and summarizes policy best practices that energy ministers and other stakeholders can pursue to ensure that electricity markets and power systems can effectively coevolve with increasing penetrations of variable renewable energy. Each country has crafted its own combination of policies, market designs, and system operations to achieve the system reliability and flexibility needed to successfully integrate renewables. Notwithstanding this diversity, the approaches taken by the countries studied all coalesce around five strategic areas: lead public engagement, particularly for new transmission; coordinate and integrate planning; develop rules for market evolution that enable system flexibility; expand access to diverse resources and geographic footprint of operations; and improve system operations. The ability to maintain a broad ecosystem perspective, to organize and make available the wealth of experiences, and to ensure a clear path from analysis to enactment should be the primary focus going forward.

  18. Inferring brain variability from diffeomorphic deformations of currents: an integrative approach

    PubMed Central

    Durrleman, Stanley; Pennec, Xavier; Trouvé, Alain; Thompson, Paul; Ayache, Nicholas

    2008-01-01

    In the context of computational anatomy, one aims at understanding and modelling the anatomy of the brain and its variations across a population. This geometrical variability is often measured from precisely defined anatomical landmarks such as sulcal lines or meshes of brain structures. This requires (1) to compare geometrical objects without introducing too many non realistic priors and (2) to retrieve the variability of the whole brain from the variability of the landmarks. We propose, in this paper, to infer a statistical brain model from the consistent integration of variability of sulcal lines. The similarity between two sets of lines is measured by a distance on currents that does not assume any type of point correspondences and it is not sensitive to the sampling of lines. This shape similarity measure is used in a diffeomorphic registrations which retrieves a single deformation of the whole 3D space. This diffeomorphism integrates the variability of all lines in a as spatially consistent manner as possible. Based on repeated pairwise registrations on a large database, we learn how the mean anatomy varies in a population by computing statistics on diffeomorphisms. Whereas usual methods lead to descriptive measures of variability, such as variability maps or statistical tests, our model is generative: we can simulate new observations according to the learned probability law on deformations. In practice, this variability captured by the model is synthesized in the principal modes of deformations. As a deformation is dense, we can also apply it to other anatomical structures defined in the template space. This is illustrated the action of the principal modes of deformations to a mean cortical surface. Eventually, our current-based diffeomorphic registration (CDR) approach is carefully compared to a pointwise line correspondences (PLC) method. Variability measures are computed with both methods on the same dataset of sulcal lines. The results suggest that we

  19. Identification of shear buildings using an instrumental variable method and linear integral filters

    NASA Astrophysics Data System (ADS)

    Concha, Antonio; Garrido, Rubén; Alvarez-Icaza, Luis

    2016-12-01

    This paper develops a method for estimating the parameters of a seismically excited building. Acceleration measurements of the ground and of the building floors, containing offsets and noise, are used for identification purposes. The proposed scheme estimates the complete model of the building if all the floors are equipped with accelerometers. Moreover, it also estimates a reduced model of the structure if only some floors are instrumented. The methodology is based on the combined use of the Instrumental Variable method and Linear Integral Filters. The Instrumental Variable method employs as instrument an auxiliary model of the structure, and it is able to directly identify the continuous-time structure model using discrete-time data without resorting on model transformations from continuous-time to discrete-time, and vice-versa. Using Linear Integral Filters allows obtaining a linear in the parameters expression that depends only on acceleration measurements suitable for parameter identification purposes. These filters eliminate measurement offsets and attenuate high-frequency measurement noise. The above features together with the use of the Instrumental variable method reduce the likelihood of biased parameter estimates. Experiments on a testbed employing a reduced-scale five-story structure allow comparing the results obtained using the Instrumental Variable method and those produced by the standard Least Squares method.

  20. A fully Bayesian latent variable model for integrative clustering analysis of multi-type omics data.

    PubMed

    Mo, Qianxing; Shen, Ronglai; Guo, Cui; Vannucci, Marina; Chan, Keith S; Hilsenbeck, Susan G

    2017-05-24

    Identification of clinically relevant tumor subtypes and omics signatures is an important task in cancer translational research for precision medicine. Large-scale genomic profiling studies such as The Cancer Genome Atlas (TCGA) Research Network have generated vast amounts of genomic, transcriptomic, epigenomic, and proteomic data. While these studies have provided great resources for researchers to discover clinically relevant tumor subtypes and driver molecular alterations, there are few computationally efficient methods and tools for integrative clustering analysis of these multi-type omics data. Therefore, the aim of this article is to develop a fully Bayesian latent variable method (called iClusterBayes) that can jointly model omics data of continuous and discrete data types for identification of tumor subtypes and relevant omics features. Specifically, the proposed method uses a few latent variables to capture the inherent structure of multiple omics data sets to achieve joint dimension reduction. As a result, the tumor samples can be clustered in the latent variable space and relevant omics features that drive the sample clustering are identified through Bayesian variable selection. This method significantly improve on the existing integrative clustering method iClusterPlus in terms of statistical inference and computational speed. By analyzing TCGA and simulated data sets, we demonstrate the excellent performance of the proposed method in revealing clinically meaningful tumor subtypes and driver omics features. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Comparison of Fixed and Variable Time Step Trajectory Integration Methods for Cislunar Trajectories

    NASA Technical Reports Server (NTRS)

    Weeks, ichael W.; Thrasher, Stephen W.

    2007-01-01

    Due to the nonlinear nature of the Earth-Moon-Sun three-body problem and non-spherical gravity, CEV cislunar targeting algorithms will require many propagations in their search for a desired trajectory. For on-board targeting especially, the algorithm must have a simple, fast, and accurate propagator to calculate a trajectory with reasonable computation time, and still be robust enough to remain stable in the various flight regimes that the CEV will experience. This paper compares Cowell s method with a fourth-order Runge- Kutta integrator (RK4), Encke s method with a fourth-order Runge-Kutta- Nystr m integrator (RKN4), and a method known as Multi-Conic. Additionally, the study includes the Bond-Gottlieb 14-element method (BG14) and extends the investigation of Encke-Nystrom methods to integrators of higher order and with variable step size.

  2. Effect of integral yoga on psychological and health variables and their correlations.

    PubMed

    Khemka, Sushil S; Ramarao, Nagendra Hongasandra; Hankey, Alex

    2011-07-01

    Certain psychological and health variables are commonly measured in India. This study evaluates the effects of integral yoga practices on these variables and also the consistency of correlations observed between them. The study was a pre-post intervention study. The variables were measured at the beginning and the end of a one-month yoga course. There was no control group.The study was carried out at Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) University, in its rural campus south of Bangalore. Based on health criteria, 108 subjects were selected out of 198 volunteers to form the experimental yoga group. Ages ranged from 17 to 63 years. The yogasanas (postures), pranayama (breathing exercises), relaxation techniques, meditation, chanting and lectures were the components of yoga intervention. The variables measured were sustained attention, emotional intelligence - EQ, general health - GHQ, guna personality - sattva, rajas and tamas. Significant pre-post changes were found in all variables. Significant correlations were found between the following pairs: The two sustained attention variables; emotional intelligence and general health; GHQ and tamas; sattva and tamas; and rajas and tamas. The study shows that there were significant changes in all variables (P< 0.001) except in sattva. It also confirms that EQ and general health variables correlate significantly with each other and negatively with tamas. EQ and tamas form positive and negative predictors of health respectively. Sattva correlates positively with EQ suggesting that a sattvic personality indicates better self-control. This suggests that, by improving guna personality, long-term yoga practice may stabilize EQ.

  3. Effect of integral yoga on psychological and health variables and their correlations

    PubMed Central

    Khemka, Sushil S; Ramarao, Nagendra Hongasandra; Hankey, Alex

    2011-01-01

    Objective: Certain psychological and health variables are commonly measured in India. This study evaluates the effects of integral yoga practices on these variables and also the consistency of correlations observed between them. Materials and Methods: The study was a pre-post intervention study. The variables were measured at the beginning and the end of a one-month yoga course. There was no control group.The study was carried out at Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) University, in its rural campus south of Bangalore. Based on health criteria, 108 subjects were selected out of 198 volunteers to form the experimental yoga group. Ages ranged from 17 to 63 years. The yogasanas (postures), pranayama (breathing exercises), relaxation techniques, meditation, chanting and lectures were the components of yoga intervention. The variables measured were sustained attention, emotional intelligence – EQ, general health – GHQ, guna personality – sattva, rajas and tamas. Results: Significant pre-post changes were found in all variables. Significant correlations were found between the following pairs: The two sustained attention variables; emotional intelligence and general health; GHQ and tamas; sattva and tamas; and rajas and tamas. Conclusion: The study shows that there were significant changes in all variables (P< 0.001) except in sattva. It also confirms that EQ and general health variables correlate significantly with each other and negatively with tamas. EQ and tamas form positive and negative predictors of health respectively. Sattva correlates positively with EQ suggesting that a sattvic personality indicates better self-control. This suggests that, by improving guna personality, long-term yoga practice may stabilize EQ. PMID:22022128

  4. White matter integrity supports BOLD signal variability and cognitive performance in the aging human brain.

    PubMed

    Burzynska, Agnieszka Z; Wong, Chelsea N; Voss, Michelle W; Cooke, Gillian E; McAuley, Edward; Kramer, Arthur F

    2015-01-01

    Decline in cognitive performance in old age is linked to both suboptimal neural processing in grey matter (GM) and reduced integrity of white matter (WM), but the whole-brain structure-function-cognition associations remain poorly understood. Here we apply a novel measure of GM processing-moment-to-moment variability in the blood oxygenation level-dependent signal (SDBOLD)-to study the associations between GM function during resting state, performance on four main cognitive domains (i.e., fluid intelligence, perceptual speed, episodic memory, vocabulary), and WM microstructural integrity in 91 healthy older adults (aged 60-80 years). We modeled the relations between whole-GM SDBOLD with cognitive performance using multivariate partial least squares analysis. We found that greater SDBOLD was associated with better fluid abilities and memory. Most of regions showing behaviorally relevant SDBOLD (e.g., precuneus and insula) were localized to inter- or intra-network "hubs" that connect and integrate segregated functional domains in the brain. Our results suggest that optimal dynamic range of neural processing in hub regions may support cognitive operations that specifically rely on the most flexible neural processing and complex cross-talk between different brain networks. Finally, we demonstrated that older adults with greater WM integrity in all major WM tracts had also greater SDBOLD and better performance on tests of memory and fluid abilities. We conclude that SDBOLD is a promising functional neural correlate of individual differences in cognition in healthy older adults and is supported by overall WM integrity.

  5. Modeling Sea-Level Change using Errors-in-Variables Integrated Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Cahill, Niamh; Parnell, Andrew; Kemp, Andrew; Horton, Benjamin

    2014-05-01

    We perform Bayesian inference on historical and late Holocene (last 2000 years) rates of sea-level change. The data that form the input to our model are tide-gauge measurements and proxy reconstructions from cores of coastal sediment. To accurately estimate rates of sea-level change and reliably compare tide-gauge compilations with proxy reconstructions it is necessary to account for the uncertainties that characterize each dataset. Many previous studies used simple linear regression models (most commonly polynomial regression) resulting in overly precise rate estimates. The model we propose uses an integrated Gaussian process approach, where a Gaussian process prior is placed on the rate of sea-level change and the data itself is modeled as the integral of this rate process. The non-parametric Gaussian process model is known to be well suited to modeling time series data. The advantage of using an integrated Gaussian process is that it allows for the direct estimation of the derivative of a one dimensional curve. The derivative at a particular time point will be representative of the rate of sea level change at that time point. The tide gauge and proxy data are complicated by multiple sources of uncertainty, some of which arise as part of the data collection exercise. Most notably, the proxy reconstructions include temporal uncertainty from dating of the sediment core using techniques such as radiocarbon. As a result of this, the integrated Gaussian process model is set in an errors-in-variables (EIV) framework so as to take account of this temporal uncertainty. The data must be corrected for land-level change known as glacio-isostatic adjustment (GIA) as it is important to isolate the climate-related sea-level signal. The correction for GIA introduces covariance between individual age and sea level observations into the model. The proposed integrated Gaussian process model allows for the estimation of instantaneous rates of sea-level change and accounts for all

  6. An integrated crop- and soil-based strategy for variable-rate nitrogen management in corn

    NASA Astrophysics Data System (ADS)

    Roberts, Darrin F.

    Nitrogen (N) management in cereal crops has been the subject of considerable research and debate for several decades. Historic N management practices have contributed to low nitrogen use efficiency (NUE). Low NUE can be caused by such things as poor synchronization between soil N supply and crop demand, uniform application rates of fertilizer N to spatially variable landscapes, and failure to account for temporally variable influences on soil N supply and crop N need. Active canopy reflectance sensors and management zones (MZ) have been studied separately as possible plant- and soil-based N management tools to increase NUE. Recently, some have suggested that the integration of these two approaches would provide a more robust N management strategy that could more effectively account for soil and plant effects on crop N need. For this reason, the goal of this research was to develop an N application strategy that would account for spatial variability in soil properties and use active canopy reflectance sensors to determine in-season, on-the-go N fertilizer rates, thereby increasing NUE and economic return for producers over current N management practices. To address this overall goal, a series of studies were conducted to better understand active canopy sensor use and explore the possibility of integrating spatial soil data with active canopy sensors. Sensor placement to assess crop N status was first examined. It was found that the greatest reduction in error over sensing each individual row for a hypothetical 24-row applicator was obtained with 2-3 sensors estimating an average chlorophyll index for the entire boom width. Next, use of active sensor-based soil organic matter (OM) estimation was compared to more conventional aerial image-based soil OM estimation. By adjusting regression intercept values for each field, OM could be predicted using either a single sensor or image data layer. The final study consisted of validation of the active sensor algorithm

  7. Climate Variability and Ponderosa Pine Colonizations in Central Wyoming: Integrating Dendroecology and Dendroclimatology

    NASA Astrophysics Data System (ADS)

    Lesser, M.; Wentzel, C.; Gray, S.; Jackson, S.

    2007-12-01

    Many tree species are predicted to expand into new territory over the coming decades in response to changing climate. By studying tree expansions over the last several centuries we can begin to understand the mechanisms underlying these changes and anticipate their consequences for forest management. Woody-plant demographics and decadal to multidecadal climate variability are often closely linked in semi-arid regions. Integrated tree-ring analysis, combining dendroecology and dendroclimatology to document, respectively, the demographic history of the population and the climatic history of the region, can reveal ecological dynamics in response to climate variability. We studied four small, disjunct populations of Pinus ponderosa in the Bighorn Basin of north-central Wyoming. These populations are located 30 to 100 kilometers from the nearest core populations of ponderosa pine in the western Bighorn Mountains. Packrat midden studies have shown that ponderosa pine colonized the western slopes of the Bighorn Range 1500 years ago, so the disjunct populations in the basin must be younger. All trees (living and dead) at each of the four disjunct populations were mapped, cored, and then aged using tree-ring based techniques. We obtained records of hydroclimatic variability from the Bighorn Basin using four tree-ring series from Pinus flexilis (3 sites) and Pseudotsuga menziesii (1 site). The four disjunct populations were all established within the past 500 years. Initially, the populations grew slowly with low recruitment rates until the early 19th century, when they experienced one or more large recruitment pulses. These pulses coincided with extended wet periods in the climate reconstruction. However, similar wet periods before the 19th Century were not accompanied by recruitment pulses, indicating that other factors (e.g., population density, genetic variability) are also important in colonization and expansion. We are currently obtaining genetic data and carrying out

  8. Benefits of variable rotor speed in integrated helicopter/engine control

    NASA Technical Reports Server (NTRS)

    Iwata, Takanori; Rock, Stephen M.

    1993-01-01

    Current helicopter flight and propulsion controls are typically designed with the assumption that rotor speed will be held to a constant setpoint. A new flight and propulsion control system using a continuously variable rotor speed command is proposed to improve the maneuverability and agility of helicopter systems. In this new approach, the flight control system generates an optimal variable rotor speed command in addition to conventional control commands in a framework of integrated flight/propulsion control. The benefits (i.e. improved maneuverability and agility) of varying rotor speed during transient maneuvers are demonstrated using a bob-up maneuver as an example. In particular, two types of benefits are identified in different maneuver conditions. One comes from a thrust augmentation, while the other comes from an exchange of rotational and translational energy. In the example, a simple linear dynamic hover model is used with an optimal control design method to generate the optimal rotor speed command.

  9. Mapping variable ring polymer molecular dynamics: A path-integral based method for nonadiabatic processes

    NASA Astrophysics Data System (ADS)

    Ananth, Nandini

    2013-09-01

    We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a model dynamics for the direct simulation of multi-electron processes. An extension of the RPMD idea, this method is based on an exact, imaginary time path-integral representation of the quantum Boltzmann operator using continuous Cartesian variables for both electronic states and nuclear degrees of freedom. We demonstrate the accuracy of the MV-RPMD approach in calculations of real-time, thermal correlation functions for a range of two-state single-mode model systems with different coupling strengths and asymmetries. Further, we show that the ensemble of classical trajectories employed in these simulations preserves the Boltzmann distribution and provides a direct probe into real-time coupling between electronic state transitions and nuclear dynamics.

  10. Path integral centroid variables and the formulation of their exact real time dynamics

    NASA Astrophysics Data System (ADS)

    Jang, Seogjoo; Voth, Gregory A.

    1999-08-01

    A formalism is presented in this paper which, for the first time, establishes the theoretical basis for the quantum time evolution of path integral centroid variables and also provides clear motivation for using these variables to study condensed phase quantum dynamics. The equilibrium centroid distribution is first shown to be a well-defined distribution function which is specific to the canonical density operator. A quantum mechanical quasi-density operator (QDO) is associated with each value of the distribution so that, upon application of the standard quantum mechanical formalism, the QDO can be used to provide a rigorous definition of both static and dynamical centroid variables. Various properties of the dynamical centroid variables are derived, including the perspective that the centroid constraint on the imaginary time paths introduces a nonstationarity in the equilibrium ensemble which, in turn, can be shown to yield information on the correlations of spontaneous fluctuations. The analytic solution for the harmonic oscillator and a numerical solution for a double well system are provided which illustrate the various aspects of the theory. The theory contained herein provides the basis for a derivation of Centroid Molecular Dynamics, as well as the systematic improvements of that theory.

  11. A novel integrated spatial filtering detector chip with variable multi-valued weighting functions

    NASA Astrophysics Data System (ADS)

    Go, H. M.; Ohyama, S.

    2006-04-01

    A novel integrated spatial filtering detector chip was introduced in this paper through the comparison with the conventional spatial filtering detectors. We designed and fabricated a novel integrated spatial filtering detector chip with variable multi-valued weighting function using CMOS 0.35µm process. This chip has 7-bit signed weight values and a weighting control circuit though the external interface with the PC. The multiplication of the frequencies is available from the dividing the weighting function of the chip. In order to con.rm the validity of this chip, a simple velocity measurement was achieved. Experimental results show multiplied frequency ratio regarding to the reference frequency which are in proportion to the velocity of the measuring object.

  12. Solar Reserve Methodology for Renewable Energy Integration Studies Based on Sub-Hourly Variability Analysis: Preprint

    SciTech Connect

    Ibanez, E.; Brinkman, G.; Hummon, M.; Lew, D.

    2012-08-01

    Increasing penetrations of wind a solar energy are raising concerns among electric system operators because of the variability and uncertainty associated with power sources. Previous work focused on the quantification of reserves for systems with wind power. This paper presents a new methodology that allows the determination of necessary reserves for high penetrations of photovoltaic (PV) power and compares it to the wind-based methodology. The solar reserve methodology is applied to Phase 2 of the Western Wind and Solar Integration Study. A summary of the results is included.

  13. Integrity of head and tail plasmalemma is associated with different kinetic variables in boar sperm.

    PubMed

    Grieblová, Adéla; Pintus, Eliana; Ros-Santaella, José Luis

    2017-09-01

    An intact and functional sperm plasmalemma has a major role in sperm motility and fertilizing capacity. Several techniques have been developed to evaluate the integrity of the sperm plasma membrane, but there are still some inconsistencies concerning the methods that are more closely associated with sperm function. In this study, the aim was to: i) evaluate the integrity of the boar sperm plasmalemma during 72h of semen storage at 17°C using four techniques: eosin/nigrosin (E/N), propidium iodide/carboxyfluorescein diacetate (PI/CFDA), hypo-osmotic swelling test (HOST), and combined HOST with eosin staining (HOST/E), ii) assess the correlations and the limits of consistency among these techniques, iii) and estimate the relationships with the acrosomal status and sperm kinetics. Results indicate that the integrity of the sperm plasmalemma decreases during 72h of storage, although significant differences were found only using the HOST and HOST/E techniques. Moreover, use of E/N and PI/CFDA results in greater values relative to the undamaged sperm membrane than use of HOST and HOST/E at any incubation time. Overall, results using all techniques were consistent and correlate except for findings with PI/CFDA and HOST, which was slightly below 95%. Moreover, values using the techniques for the evaluation of the integrity of the sperm head and tail membranes are positively associated with the acrosomal status and different kinetic variables with the tail integrity being related to rapid linear trajectories and the head integrity to rapid curvilinear trajectories. The results of this study provide new insights into the relevance of evaluating the boar sperm plasmalemma in the routine spermiogram. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Criterion of the boundedness of a fractional integration type operator with variable upper limit in weighted Lebesgue spaces

    NASA Astrophysics Data System (ADS)

    Abylayeva, Akbota

    2016-08-01

    In this paper, the necessary and sufficient conditions of the boundedness of a fractional integration type operator with variable upper limit are obtained under different parameters in weighted Lebesgue spaces.

  15. Fossil fleet transition with fuel changes and large scale variable renewable integration

    SciTech Connect

    James, Revis; Hesler, Stephen; Bistline, John

    2015-03-31

    Variability in demand as seen by grid-connected dispatchable generators can increase due to factors such as greater production from variable generation assets (for example, wind and solar), increased reliance on demand response or customer-driven automation, and aggregation of loads. This variability results a need for these generators to operate in a range of different modes, collectively referred to as “flexible operations.” This study is designed to inform power companies, researchers, and policymakers of the scope and trends in increasing levels of flexible operations as well as reliability challenges and impacts for dispatchable assets. Background Because there is rarely a direct monetization of the value of operational flexibility, the decision to provide such flexibility is typically dependent on unit- and region-specific decisions made by asset owners. It is very likely that much greater and more widespread flexible operations capabilities will be needed due to increased variability in demand seen by grid-connected generators, uncertainty regarding investment in new units to provide adequate operational flexibility, and the retirement of older, uncontrolled sub-critical pulverized coal units. Objective To enhance understanding of the technical challenges and operational impacts associated with dispatchable assets needed to increase operational flexibility and support variable demand. Approach The study approach consists of three elements: a literature review of relevant prior studies, analysis of detailed scenarios for evolution of the future fleet over the next 35 years, and engineering assessment of the degree and scope of technical challenges associated with transformation to the future fleet. The study approach integrated two key elements rarely brought together in a single analysis—1) long-term capacity planning, which enables modeling of unit retirements and new asset investments, and 2) unit commitment analysis, which permits examination of

  16. A comparison of two multi-variable integrator windup protection schemes

    NASA Technical Reports Server (NTRS)

    Mattern, Duane

    1993-01-01

    Two methods are examined for limit and integrator wind-up protection for multi-input, multi-output linear controllers subject to actuator constraints. The methods begin with an existing linear controller that satisfies the specifications for the nominal, small perturbation, linear model of the plant. The controllers are formulated to include an additional contribution to the state derivative calculations. The first method to be examined is the multi-variable version of the single-input, single-output, high gain, Conventional Anti-Windup (CAW) scheme. Except for the actuator limits, the CAW scheme is linear. The second scheme to be examined, denoted the Modified Anti-Windup (MAW) scheme, uses a scalar to modify the magnitude of the controller output vector while maintaining the vector direction. The calculation of the scalar modifier is a nonlinear function of the controller outputs and the actuator limits. In both cases the constrained actuator is tracked. These two integrator windup protection methods are demonstrated on a turbofan engine control system with five measurements, four control variables, and four actuators. The closed-loop responses of the two schemes are compared and contrasted during limit operation. The issue of maintaining the direction of the controller output vector using the Modified Anti-Windup scheme is discussed and the advantages and disadvantages of both of the IWP methods are presented.

  17. Integrating Variable Renewable Energy in Electric Power Markets. Best Practices from International Experience, Summary for Policymakers

    SciTech Connect

    Cochran, Jaquelin; Bird, Lori; Heeter, Jenny; Arent, Douglas J.

    2012-04-30

    Many countries - reflecting very different geographies, markets, and power systems - are successfully managing high levels of variable renewable energy on the electric grid, including that from wind and solar energy. This document summarizes policy best practices that energy ministers and other stakeholders can pursue to ensure that electricity markets and power systems can effectively coevolve with increasing penetrations of variable renewable energy. There is no one-size-fits-all approach; each country studied has crafted its own combination of policies, market designs, and system operations to achieve the system reliability and flexibility needed to successfully integrate renewables. Notwithstanding this diversity, the approaches taken by the countries studied all coalesce around five strategic areas: lead public engagement, particularly for new transmission; coordinate and integrate planning; develop rules for market evolution that enable system flexibility; expand access to diverse resources and geographic footprint of operations; and improve system operations. This study also emphatically underscores the value of countries sharing their experiences. The more diverse and robust the experience base from which a country can draw, the more likely that it will be able to implement an appropriate, optimized, and system-wide approach.

  18. Integrating Variable Renewable Energy in Electric Power Markets: Best Practices from International Experience, Summary for Policymakers

    SciTech Connect

    Cochran, J.; Bird, L.; Heeter, J.; Arent, D. A.

    2012-04-01

    Many countries -- reflecting very different geographies, markets, and power systems -- are successfully managing high levels of variable renewable energy on the electric grid, including that from wind and solar energy. This document summarizes policy best practices that energy ministers and other stakeholders can pursue to ensure that electricity markets and power systems can effectively coevolve with increasing penetrations of variable renewable energy. There is no one-size-fits-all approach; each country studied has crafted its own combination of policies, market designs, and system operations to achieve the system reliability and flexibility needed to successfully integrate renewables. Notwithstanding this diversity, the approaches taken by the countries studied all coalesce around five strategic areas: lead public engagement, particularly for new transmission; coordinate and integrate planning; develop rules for market evolution that enable system flexibility; expand access to diverse resources and geographic footprint of operations; and improve system operations. This study also emphatically underscores the value of countries sharing their experiences. The more diverse and robust the experience base from which a country can draw, the more likely that it will be able to implement an appropriate, optimized, and system-wide approach.

  19. Integrating Variable Renewable Energy in Electric Power Markets. Best Practices from International Experience

    SciTech Connect

    Cochran, Jaquelin; Bird, Lori; Heeter, Jenny; Arent, Douglas J.

    2012-04-30

    Many countries—reflecting very different geographies, markets, and power systems—are successfully managing high levels of variable renewable energy on the electric grid, including that from wind and solar energy. This document summarizes policy best practices that energy ministers and other stakeholders can pursue to ensure that electricity markets and power systems can effectively coevolve with increasing penetrations of variable renewable energy. There is no one-size-fits-all approach; each country studied has crafted its own combination of policies, market designs, and system operations to achieve the system reliability and flexibility needed to successfully integrate renewables. Notwithstanding this diversity, the approaches taken by the countries studied all coalesce around five strategic areas: lead public engagement, particularly for new transmission; coordinate and integrate planning; develop rules for market evolution that enable system flexibility; expand access to diverse resources and geographic footprint of operations; and improve system operations. This study also emphatically underscores the value of countries sharing their experiences. The more diverse and robust the experience base from which a country can draw, the more likely that it will be able to implement an appropriate, optimized, and system-wide approach.

  20. White Matter Integrity Supports BOLD Signal Variability and Cognitive Performance in the Aging Human Brain

    PubMed Central

    Burzynska, Agnieszka Z.; Wong, Chelsea N.; Voss, Michelle W.; Cooke, Gillian E.; McAuley, Edward; Kramer, Arthur F.

    2015-01-01

    Decline in cognitive performance in old age is linked to both suboptimal neural processing in grey matter (GM) and reduced integrity of white matter (WM), but the whole-brain structure-function-cognition associations remain poorly understood. Here we apply a novel measure of GM processing–moment-to-moment variability in the blood oxygenation level-dependent signal (SDBOLD)—to study the associations between GM function during resting state, performance on four main cognitive domains (i.e., fluid intelligence, perceptual speed, episodic memory, vocabulary), and WM microstructural integrity in 91 healthy older adults (aged 60-80 years). We modeled the relations between whole-GM SDBOLD with cognitive performance using multivariate partial least squares analysis. We found that greater SDBOLD was associated with better fluid abilities and memory. Most of regions showing behaviorally relevant SDBOLD (e.g., precuneus and insula) were localized to inter- or intra-network “hubs” that connect and integrate segregated functional domains in the brain. Our results suggest that optimal dynamic range of neural processing in hub regions may support cognitive operations that specifically rely on the most flexible neural processing and complex cross-talk between different brain networks. Finally, we demonstrated that older adults with greater WM integrity in all major WM tracts had also greater SDBOLD and better performance on tests of memory and fluid abilities. We conclude that SDBOLD is a promising functional neural correlate of individual differences in cognition in healthy older adults and is supported by overall WM integrity. PMID:25853882

  1. Evaluating the Impacts of Climate variability on Agriculture: an integrated modeling approach

    NASA Astrophysics Data System (ADS)

    Ahmad, S.; Miralles-Wilhelm, F. R.; Podestá, G. P.; Broad, K.; Letson, D.

    2005-05-01

    Climate variability is just one factor that affects agriculture, other factors such as socio-economic conditions, demographic changes, land use and land cover changes, and water allocation policies also have significant impacts. In this research, the exposure of Florida agriculture to multiple stresses is analyzed using an integrated modeling approach, based on system dynamics modeling principles. The model consists of five interacting sectors of population, land use, water use, pollution and economy. Land use is further divided into urban/industrial, farmland, commercial forest, and state forest. Water use consists of demand for domestic, industrial, agricultural, environmental, and recreational purposes. The framework of the model is described, and the results of alternate policy runs and a sensitivity analysis are presented. The integrated model is used to explore three policy scenarios. First, we explore if current trends of demographic change, water use and land use continue, what will happen under different climate variability scenarios (i.e., change in temperature and precipitation, both in time and space). Second, we explore scenarios with changes in water demand and supply through adding desalinization plants, reducing water losses, preserving water through efficient use, changing crop variety and pattern, and importing virtual water. Third, we explore scenarios based on land use changes considering land allocation for alternate uses (e.g., changing commercial forest to agricultural use) and changing land use within certain category (e.g., different crops within agricultural land use). The research advances work on estimating the impacts of climate variability on agriculture by considering dynamic interaction among multiple influencing factors. The results should help agencies involved in management of agriculture and water resources in Florida to develop policies for sustainable management of these resources.

  2. Operational constraints and hydrologic variability limit hydropower in supporting wind integration

    NASA Astrophysics Data System (ADS)

    Fernandez, Alisha R.; Blumsack, Seth A.; Reed, Patrick M.

    2013-06-01

    Climate change mitigation will require rapid adoption of low-carbon energy resources. The integration of large-scale wind energy in the United States (US) will require controllable assets to balance the variability of wind energy production. Previous work has identified hydropower as an advantageous asset, due to its flexibility and low-carbon emissions production. While many dams currently provide energy and environmental services in the US and globally, we find that multi-use hydropower facilities would face significant policy conflicts if asked to store and release water to accommodate wind integration. Specifically, we develop a model simulating hydroelectric operational decisions when the electric facility is able to provide wind integration services through a mechanism that we term ‘flex reserves’. We use Kerr Dam in North Carolina as a case study, simulating operations under two alternative reservoir policies, one reflecting current policies and the other regulating flow levels to promote downstream ecosystem conservation. Even under perfect information and significant pricing incentives, Kerr Dam faces operational conflicts when providing any substantial levels of flex reserves while also maintaining releases consistent with other river management requirements. These operational conflicts are severely exacerbated during periods of drought. Increase of payments for flex reserves does not resolve these operational and policy conflicts.

  3. Study of time-accurate integration of the variable-density Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Lu, Xiaoyi; Pantano, Carlos

    2015-11-01

    We present several theoretical elements that affect time-consistent integration of the low-Mach number approximation of variable-density Navier-Stokes equations. The goal is for velocity, pressure, density, and scalars to achieve uniform order of accuracy, consistent with the time integrator being used. We show examples of second-order (using Crank-Nicolson and Adams-Bashforth) and third-order (using additive semi-implicit Runge-Kutta) uniform convergence with the proposed conceptual framework. Furthermore, the consistent approach can be extended to other time integrators. In addition, the method is formulated using approximate/incomplete factorization methods for easy incorporation in existing solvers. One of the observed benefits of the proposed approach is improved stability, even for large density difference, in comparison with other existing formulations. A linearized stability analysis is also carried out for some test problems to better understand the behavior of the approach. This work was supported in part by the Department of Energy, National Nuclear Security Administration, under award no. DE-NA0002382 and the California Institute of Technology.

  4. Some new retarded nonlinear Volterra-Fredholm type integral inequalities with maxima in two variables and their applications.

    PubMed

    Xu, Run; Ma, Xiangting

    2017-01-01

    In this paper, we establish some new retarded nonlinear Volterra-Fredholm type integral inequalities with maxima in two independent variables, and we present the applications to research the boundedness of solutions to retarded nonlinear Volterra-Fredholm type integral equations.

  5. Time Series Analyses of Hand, Foot and Mouth Disease Integrating Weather Variables

    PubMed Central

    Song, Yuanbin; Wang, Fan; Wang, Bin; Tao, Shaohua; Zhang, Huiping; Liu, Sai; Ramirez, Oscar; Zeng, Qiyi

    2015-01-01

    Background The past decade witnessed an increment in the incidence of hand foot mouth disease (HFMD) in the Pacific Asian region; specifically, in Guangzhou China. This emphasized the requirement of an early warning system designed to allow the medical community to better prepare for outbreaks and thus minimize the number of fatalities. Methods Samples from 1,556 inpatients (hospitalized) and 11,004 outpatients (non-admitted) diagnosed with HFMD were collected in this study from January 2009 to October 2013. Seasonal Autoregressive Integrated Moving Average (SARIMA) model was applied to establish high predictive model for inpatients and outpatient as well as three viral serotypes (EV71, Pan-EV and CA16). To integrate climate variables in the data analyses, data from eight climate variables were simultaneously obtained during this period. Significant climate variable identified by correlation analyses was executed to improve time series modeling as external repressors. Results Among inpatients with HFMD, 248 (15.9%) were affected by EV71, 137 (8.8%) were affected by Pan-EV+, and 436 (28.0%) were affected by CA16. Optimal Univariate SARIMA model was identified: (2,0,3)(1,0,0)52 for inpatients, (0,1,0)(0,0,2)52 for outpatients as well as three serotypes (EV71, (1,0,1)(0,0,1)52; CA16, (1,0,1)(0,0,0)52; Pan-EV, (1,0,1)(0,0,0)52). Using climate as our independent variable, precipitation (PP) was first identified to be associated with inpatients (r = 0.211, P = 0.001), CA16-serotype (r = 0.171, P = 0.007) and outpatients (r = 0.214, P = 0.01) in partial correlation analyses, and was then shown a significant lag in cross-autocorrelation analyses. However, inclusion of PP [lag -3 week] as external repressor showed a moderate impact on the predictive performance of the SARIMA model described here-in. Conclusion Climate patterns and HFMD incidences have been shown to be strongly correlated. The SARIMA model developed here can be a helpful tool in developing an early warning

  6. Integral variable structure control of nonlinear system using a CMAC neural network learning approach.

    PubMed

    Hung, Chin-Pao

    2004-02-01

    This work presents a novel integral variable structure control (IVSC) that combines a cerebellar model articulation controller (CMAC) neural network and a soft supervisor controller for use in designing single-input single-output (SISO) nonlinear system. Based on the Lyapunov theorem, the soft supervisor controller is designed to guarantee the global stability of the system. The CMAC neural network is used to perform the equivalent control on IVSC, using a real-time learning algorithm. The proposed IVSC control scheme alleviates the dependency on system parameters and eliminates the chattering of the control signal through an efficient learning scheme. The CMAC-based IVSC (CIVSC) scheme is proven to be globally stable inasmuch all signals involved are bounded and the tracking error converges to zero. A numerical simulation demonstrates the effectiveness and robustness of the proposed controller.

  7. Diffusion tensor imaging of corpus callosum integrity in multiple sclerosis: correlation with disease variables.

    PubMed

    Sigal, Tal; Shmuel, Miron; Mark, Dolev; Gil, Harari; Anat, Achiron

    2012-01-01

    Corpus callosum (CC) is frequently involved in multiple sclerosis (MS). We aimed to investigate the relations between CC microstructure integrity as measured by diffusion tensor imaging (DTI) in relapsing-remitting MS patients with low neurological disability in comparison with age-matched healthy subjects and further to identify correlations between DTI-CC parameters and clinical variables of MS disease activity. CC volume was measured on 3.0T brain MRI by MS Analyze software. DTI metrics acquired along 31 independent directions were obtained and fractional anisotropy (FA), apparent diffusion coefficient (ADC), longitudinal (λ1) and transverse (λ 2, λ 3) diffusivities were measured in MS patients and healthy subjects. Disease activity was assessed by relapse rate and neurolgical disability by the Extended Disability Status Scale (EDSS). Thirty relapsing-remitting MS patients and 30 age- and sex-matched healthy subjects were studied. CC volume and DTI metrics differed significantly between MS patients and healthy subjects. In MS patients, all DTI parameters correlated with neurological disability. ADC, longitudinal and transverse diffusivity correlated with disease duration. ADC and the transverse diffusivity correlated with relapse rate. CC DTI parameters, especially ADC and transverse diffusivity correlated with disease variables especially with those associated with clinical activity. Copyright © 2010 by the American Society of Neuroimaging.

  8. Energy Simulation of Integrated Multiple-Zone Variable Refrigerant Flow System

    SciTech Connect

    Shen, Bo; Rice, C Keith; Baxter, Van D

    2013-01-01

    We developed a detailed steady-state system model, to simulate the performance of an integrated five-zone variable refrigerant flow (VRF)heat pump system. The system is multi-functional, capable of space cooling, space heating, combined space cooling and water heating, and dedicated water heating. Methods were developed to map the VRF performance in each mode, based on the abundant data produced by the equipment system model. The performance maps were used in TRNSYS annual energy simulations. Using TRNSYS, we have successfully setup and run cases for a multiple-split, VRF heat pump and dehumidifier combination in 5-zone houses in 5 climates that control indoor dry-bulb temperature and relative humidity. We compared the calculated energy consumptions for the VRF heat pump against that of a baseline central air source heat pump, coupled with electric water heating and the standalone dehumidifiers. In addition, we investigated multiple control scenarios for the VRF heat pump, i.e. on/off control, variable indoor air flow rate, and using different zone temperature setting schedules, etc. The energy savings for the multiple scenarios were assessed.

  9. [Integration of demographic variables in development planning: the case of Central African Republic].

    PubMed

    Bm'niyat Bangamboulou-te-niya, D

    1989-06-01

    maternal-child health project created in 1978, and the 2nd national population census is underway. These positive actions have not been integrated into a framework for population and development planning. 4 phases are viewed as necessary if integration of population and development planning is to be achieved in the Central African Republic. These phases are provision of population education to all sectors; research on population variables and links between population and development especially in employment, education, and population distribution; training and integration of skills between political authorities, planners, and researchers; and development of data bases and modelling capabilities.

  10. Numerical integration of the extended variable generalized Langevin equation with a positive Prony representable memory kernel

    SciTech Connect

    Baczewski, Andrew D.; Bond, Stephen D.

    2013-01-01

    Generalized Langevin dynamics (GLD) arise in the modeling of a number of systems, ranging from structured fluids that exhibit a viscoelastic mechanical response, to biological systems, and other media that exhibit anomalous diffusive phenomena. Molecular dynamics (MD) simulations that include GLD in conjunction with external and/or pairwise forces require the development of numerical integrators that are efficient, stable, and have known convergence properties. In this article, we derive a family of extended variable integrators for the Generalized Langevin equation with a positive Prony series memory kernel. Using stability and error analysis, we identify a superlative choice of parameters and implement the corresponding numerical algorithm in the LAMMPS MD software package. Salient features of the algorithm include exact conservation of the first and second moments of the equilibrium velocity distribution in some important cases, stable behavior in the limit of conventional Langevin dynamics, and the use of a convolution-free formalism that obviates the need for explicit storage of the time history of particle velocities. Capability is demonstrated with respect to accuracy in numerous canonical examples, stability in certain limits, and an exemplary application in which the effect of a harmonic confining potential is mapped onto a memory kernel.

  11. VARIABILITY OF WATER AND OXYGEN ABSORPTION BANDS IN THE DISK-INTEGRATED SPECTRA OF EARTH

    SciTech Connect

    Fujii, Yuka; Suto, Yasushi; Turner, Edwin L.

    2013-03-10

    We study the variability of major atmospheric absorption features in the disk-integrated spectra of Earth with future application to Earth-analogs in mind, concentrating on the diurnal timescale. We first analyze observations of Earth provided by the EPOXI mission, and find 5%-20% fractional variation of the absorption depths of H{sub 2}O and O{sub 2} bands, two molecules that have major signatures in the observed range. From a correlation analysis with the cloud map data from the Earth Observing Satellite (EOS), we find that their variation pattern is primarily due to the uneven cloud cover distribution. In order to account for the observed variation quantitatively, we consider a simple opaque cloud model, which assumes that the clouds totally block the spectral influence of the atmosphere below the cloud layer, equivalent to assuming that the incident light is completely scattered at the cloud top level. The model is reasonably successful, and reproduces the EPOXI data from the pixel-level EOS cloud/water vapor data. A difference in the diurnal variability patterns of H{sub 2}O and O{sub 2} bands is ascribed to the differing vertical and horizontal distribution of those molecular species in the atmosphere. On Earth, the inhomogeneous distribution of atmospheric water vapor is due to the existence of its exchange with liquid and solid phases of H{sub 2}O on the planet's surface on a timescale short compared with atmospheric mixing times. If such differences in variability patterns were detected in spectra of Earth-analogs, it would provide the information on the inhomogeneous composition of their atmospheres.

  12. Toward an integrated physiological theory of microbial growth: from subcellular variables to population dynamics.

    PubMed

    Narang, Atul; Pilyugin, Sergei S

    2005-01-01

    The dynamics of microbial growth is a problem of fundamental interest in microbiology, microbial ecology, and biotechnology. The pioneering work of Jacob Monod served as a starting point for developing a wealth of mathematical models that address diferent aspects of microbial growth in batch and continuous cultures. A number of phenomenological models have appeared in the literature over the last half century. These models can capture the steady-state behavior of pure and mixed cultures, but fall short of explaining most of the complex dynamic phenomena. This is because the onset of these complex dynamics is invariably driven by one or more intracellular variables not accounted for by phenomenological models. In this paper, we provide an overview of the experimental data, and introduce a diferent class of mathematical models that can be used to understand microbial growth dynamics. In addition to the standard variables such as the cell and substrate concentrations, these models explicitly include the dynamics of the physiological variables responsible for adaptation of the cells to environmental variations. We present these physiological models in the order of increasing complexity. Thus, we begin with models of single-species growth in environments containing a single growth-limiting substrate, then advance to models of single-species growth in mixed-substrate media, and conclude with models of multiple-species growth in mixed-substrate environments. Throughout the paper, we discuss both the analytical and simulation techniques to illustrate how these models capture and explain various experimental phenomena. Finally, we also present open questions and possible directions for future research that would integrate these models into a global physiological theory of microbial growth.

  13. Variability of Water and Oxygen Absorption Bands in the Disk-integrated Spectra of Earth

    NASA Astrophysics Data System (ADS)

    Fujii, Yuka; Turner, Edwin L.; Suto, Yasushi

    2013-03-01

    We study the variability of major atmospheric absorption features in the disk-integrated spectra of Earth with future application to Earth-analogs in mind, concentrating on the diurnal timescale. We first analyze observations of Earth provided by the EPOXI mission, and find 5%-20% fractional variation of the absorption depths of H2O and O2 bands, two molecules that have major signatures in the observed range. From a correlation analysis with the cloud map data from the Earth Observing Satellite (EOS), we find that their variation pattern is primarily due to the uneven cloud cover distribution. In order to account for the observed variation quantitatively, we consider a simple opaque cloud model, which assumes that the clouds totally block the spectral influence of the atmosphere below the cloud layer, equivalent to assuming that the incident light is completely scattered at the cloud top level. The model is reasonably successful, and reproduces the EPOXI data from the pixel-level EOS cloud/water vapor data. A difference in the diurnal variability patterns of H2O and O2 bands is ascribed to the differing vertical and horizontal distribution of those molecular species in the atmosphere. On Earth, the inhomogeneous distribution of atmospheric water vapor is due to the existence of its exchange with liquid and solid phases of H2O on the planet's surface on a timescale short compared with atmospheric mixing times. If such differences in variability patterns were detected in spectra of Earth-analogs, it would provide the information on the inhomogeneous composition of their atmospheres.

  14. Higher step length variability indicates lower gray matter integrity of selected regions in older adults.

    PubMed

    Rosso, Andrea L; Olson Hunt, Megan J; Yang, Mei; Brach, Jennifer S; Harris, Tamara B; Newman, Anne B; Satterfield, Suzanne; Studenski, Stephanie A; Yaffe, Kristine; Aizenstein, Howard J; Rosano, Caterina

    2014-01-01

    Step length variability (SLV) increases with age in those without overt neurologic disease, is higher in neurologic patients, is associated with falls, and predicts dementia. Whether higher SLV in older adults without neurologic disease indicates presence of neurologic abnormalities is unknown. Our objective was to identify whether SLV in older adults without overt disease is associated with findings from multimodal neuroimaging. A well-characterized cohort of 265 adults (79-90 years) was concurrently assessed by gait mat, magnetic resonance imaging with diffusion tensor, and neurological exam. Linear regression models adjusted for gait speed, demographic, health, and functional covariates assessed associations of MRI measures (gray matter volume, white matter hyperintensity volume, mean diffusivity, fractional anisotropy) with SLV. Regional distribution of associations was assessed by sparse partial least squares analyses. Higher SLV (mean: 8.4, SD: 3.3) was significantly associated with older age, slower gait speed, and poorer executive function and also with lower gray matter integrity measured by mean diffusivity (standardized beta=0.16; p=0.02). Associations between SLV and gray matter integrity were strongest for the hippocampus and anterior cingulate gyrus (both β=0.18) as compared to other regions. Associations of SLV with other neuroimaging markers were not significant. Lower integrity of normal-appearing gray matter may underlie higher SLV in older adults. Our results highlighted the hippocampus and anterior cingulate gyrus, regions involved in memory and executive function. These findings support previous research indicating a role for cognitive function in motor control. Higher SLV may indicate focal neuropathology in those without diagnosed neurologic disease.

  15. Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration

    SciTech Connect

    Phadke, Amol; Abhyankar, NIkit; Rao, Poorvi

    2014-06-17

    We analyze variability in load and wind generation in India to assess its implications for grid integration of large scale wind projects using actual wind generation and load data from two states in India, Karnataka and Tamil Nadu. We compare the largest variations in load and net load (load ?wind, i.e., load after integrating wind) that the generation fleet has to meet. In Tamil Nadu, where wind capacity is about 53percent of the peak demand, we find that the additional variation added due to wind over the current variation in load is modest; if wind penetration reaches 15percent and 30percent by energy, the additional hourly variation is less than 0.5percent and 4.5percent of the peak demand respectively for 99percent of the time. For wind penetration of 15percent by energy, Tamil Nadu system is found to be capable of meeting the additional ramping requirement for 98.8percent of the time. Potential higher uncertainty in net load compared to load is found to have limited impact on ramping capability requirements of the system if coal plants can me ramped down to 50percent of their capacity. Load and wind aggregation in Tamil Nadu and Karnataka is found to lower the variation by at least 20percent indicating the benefits geographic diversification. These findings suggest modest additional flexible capacity requirements and costs for absorbing variation in wind power and indicate that the potential capacity support (if wind does not generate enough during peak periods) may be the issue that has more bearing on the economics of integrating wind

  16. Assessment of small-scale integrated water vapour variability during HOPE

    NASA Astrophysics Data System (ADS)

    Steinke, S.; Eikenberg, S.; Löhnert, U.; Dick, G.; Klocke, D.; Di Girolamo, P.; Crewell, S.

    2014-09-01

    The spatio-temporal variability of integrated water vapour (IWV) on small-scales of less than 10 km and hours is assessed with data from the two months of the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE). The statistical intercomparison of the unique set of observations during HOPE (microwave radiometer (MWR), Global Positioning System (GPS), sunphotometer, radiosondes, Raman Lidar, infrared and near infrared Moderate Resolution Imaging Spectroradiometer (MODIS) on the satellites Aqua and Terra) measuring close together reveals a good agreement in terms of standard deviation (≤ 1 kg m-2) and correlation coefficient (≥ 0.98). The exception is MODIS, which appears to suffer from insufficient cloud filtering. For a case study during HOPE featuring a typical boundary layer development, the IWV variability in time and space on scales of less than 10 km and less than 1 h is investigated in detail. For this purpose, the measurements are complemented by simulations with the novel ICOsahedral Non-hydrostatic modelling framework (ICON) which for this study has a horizontal resolution of 156 m. These runs show that differences in space of 3-4 km or time of 10-15 min induce IWV variabilities in the order of 4 kg m-2. This model finding is confirmed by observed time series from two MWRs approximately 3 km apart with a comparable temporal resolution of a few seconds. Standard deviations of IWV derived from MWR measurements reveal a high variability (> 1 kg m-2) even at very short time scales of a few minutes. These cannot be captured by the temporally lower resolved instruments and by operational numerical weather prediction models such as COSMO-DE (an application of the Consortium for Small-scale Modelling covering Germany) of Deutscher Wetterdienst, which is included in the comparison. However, for time scales larger than 1 h, a sampling resolution of 15 min is sufficient to capture the

  17. Assessment of small-scale integrated water vapour variability during HOPE

    NASA Astrophysics Data System (ADS)

    Steinke, S.; Eikenberg, S.; Löhnert, U.; Dick, G.; Klocke, D.; Di Girolamo, P.; Crewell, S.

    2015-03-01

    The spatio-temporal variability of integrated water vapour (IWV) on small scales of less than 10 km and hours is assessed with data from the 2 months of the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE). The statistical intercomparison of the unique set of observations during HOPE (microwave radiometer (MWR), Global Positioning System (GPS), sun photometer, radiosondes, Raman lidar, infrared and near-infrared Moderate Resolution Imaging Spectroradiometer (MODIS) on the satellites Aqua and Terra) measuring close together reveals a good agreement in terms of random differences (standard deviation ≤1 kg m-2) and correlation coefficient (≥ 0.98). The exception is MODIS, which appears to suffer from insufficient cloud filtering. For a case study during HOPE featuring a typical boundary layer development, the IWV variability in time and space on scales of less than 10 km and less than 1 h is investigated in detail. For this purpose, the measurements are complemented by simulations with the novel ICOsahedral Nonhydrostatic modelling framework (ICON), which for this study has a horizontal resolution of 156 m. These runs show that differences in space of 3-4 km or time of 10-15 min induce IWV variabilities on the order of 0.4 kg m-2. This model finding is confirmed by observed time series from two MWRs approximately 3 km apart with a comparable temporal resolution of a few seconds. Standard deviations of IWV derived from MWR measurements reveal a high variability (> 1 kg m-2) even at very short time scales of a few minutes. These cannot be captured by the temporally lower-resolved instruments and by operational numerical weather prediction models such as COSMO-DE (an application of the Consortium for Small-scale Modelling covering Germany) of Deutscher Wetterdienst, which is included in the comparison. However, for time scales larger than 1 h, a sampling resolution of 15 min is

  18. Event triggered state estimation techniques for power systems with integrated variable energy resources.

    PubMed

    Francy, Reshma C; Farid, Amro M; Youcef-Toumi, Kamal

    2015-05-01

    For many decades, state estimation (SE) has been a critical technology for energy management systems utilized by power system operators. Over time, it has become a mature technology that provides an accurate representation of system state under fairly stable and well understood system operation. The integration of variable energy resources (VERs) such as wind and solar generation, however, introduces new fast frequency dynamics and uncertainties into the system. Furthermore, such renewable energy is often integrated into the distribution system thus requiring real-time monitoring all the way to the periphery of the power grid topology and not just the (central) transmission system. The conventional solution is two fold: solve the SE problem (1) at a faster rate in accordance with the newly added VER dynamics and (2) for the entire power grid topology including the transmission and distribution systems. Such an approach results in exponentially growing problem sets which need to be solver at faster rates. This work seeks to address these two simultaneous requirements and builds upon two recent SE methods which incorporate event-triggering such that the state estimator is only called in the case of considerable novelty in the evolution of the system state. The first method incorporates only event-triggering while the second adds the concept of tracking. Both SE methods are demonstrated on the standard IEEE 14-bus system and the results are observed for a specific bus for two difference scenarios: (1) a spike in the wind power injection and (2) ramp events with higher variability. Relative to traditional state estimation, the numerical case studies showed that the proposed methods can result in computational time reductions of 90%. These results were supported by a theoretical discussion of the computational complexity of three SE techniques. The work concludes that the proposed SE techniques demonstrate practical improvements to the computational complexity of

  19. Evaluating Depth-Integrated Steric Contributions to Sea-Level Trends and Variability in Earth System Model Ensembles

    NASA Astrophysics Data System (ADS)

    Hogan, E.; Sriver, R. L.

    2015-12-01

    Earth system model ensembles exhibit considerable uncertainties surrounding trends and magnitude of steric sea-level variations, due in part to structural model differences, internal model variability, and parameterizations that influence ocean heat uptake. Here we analyze depth-integrated steric sea-level changes using the CMIP5 models and a new CESM ensemble that samples internal variability of the coupled Earth system. The CESM ensemble contains 50 members, with historical and future projections (1850-2100) initialized from unique model states sampled from a ~10,000 year fully coupled unforced equilibrium simulation. The CESM ensemble enables us to examine how initial conditions uncertainty (internal variability) within the full-ocean can influence depth-integrated steric sea-level variability. The second ensemble is comprised of runs from 32 different CMIP5 models. We performed grid-level drift correction for each model using the pre-industrial control simulations, which enables us to examine depth-integrated variability and trends due to different model structures. We compare and contrast our results with published observational datasets, and we analyze the effect of different sources of uncertainty on simulated sea-level variability and trends for different ocean depths. Results point to the importance of the deep ocean in attempting to attribute and predict temporal patterns of steric sea-level on a global scale.

  20. Development of a Variable-Speed Residential Air-Source Integrated Heat Pump

    SciTech Connect

    Rice, C Keith; Shen, Bo; Munk, Jeffrey D; Ally, Moonis Raza; Baxter, Van D

    2014-01-01

    A residential air-source integrated heat pump (AS-IHP) is under development in partnership with a U.S. manufacturer. A nominal 10.6 kW (3-ton) cooling capacity variable-speed unit, the system provides both space conditioning and water heating. This multi-functional unit can provide domestic water heating (DWH) in either full condensing (FC) (dedicated water heating or simultaneous space cooling and water heating) or desuperheating (DS) operation modes. Laboratory test data were used to calibrate a vapor-compression simulation model for each mode of operation. The model was used to optimize the internal control options for efficiency while maintaining acceptable comfort conditions and refrigerant-side pressures and temperatures within allowable operating envelopes. Annual simulations were performed with the AS-IHP installed in a well-insulated house in five U.S. climate zones. The AS-IHP is predicted to use 45 to 60% less energy than a DOE minimum efficiency baseline system while meeting total annual space conditioning and water heating loads. Water heating energy use is lowered by 60 to 75% in cold to warmer climates, respectively. Plans are to field test the unit in Knoxville, TN.

  1. Food safety objectives should integrate the variability of the concentration of pathogen.

    PubMed

    Rieu, Emilie; Duhem, Koenraad; Vindel, Elisabeth; Sanaa, Moez

    2007-04-01

    The World Trade Organization introduced the concept of appropriate level of protection (ALOP) as a public health target. For this public health objective to be interpretable by the actors in the food chain, the concept of food safety objective (FSO) was proposed by the International Commission on Microbiological Specifications for Foods and adopted later by the Codex Alimentarius Food Hygiene Committee. The way to translate an ALOP into a FSO is still in debate. The purpose of this article is to develop a methodological tool to derive a FSO from an ALOP being expressed as a maximal annual marginal risk. We explore the different models relating the annual marginal risk to the parameters of the FSO depending on whether the variability in the survival probability and in the concentration of the pathogen are considered or not. If they are not, determination of the FSO is straightforward. If they are, we propose to use stochastic Monte Carlo simulation models and logistic discriminant analysis in order to determine which sets of parameters are compatible with the ALOP. The logistic discriminant function was chosen such that the kappa coefficient is maximized. We illustrate this method by the example of the risks of listeriosis and salmonellosis in one type of soft cheese. We conclude that the definition of the FSO should integrate three dimensions: the prevalence of contamination, the average concentration per contaminated typical serving, and the dispersion of the concentration among those servings.

  2. PHOTOMETRIC VARIABILITY OF THE DISK-INTEGRATED THERMAL EMISSION OF THE EARTH

    SciTech Connect

    Gomez-Leal, I.; Selsis, F.; Palle, E. E-mail: selsis@obs.u-bordeaux1.fr

    2012-06-10

    Here we present an analysis of the global-integrated mid-infrared emission flux of the Earth based on data derived from satellite measurements. We have studied the photometric annual, seasonal, and rotational variability of the thermal emission of the Earth to determine which properties can be inferred from the point-like signal. We find that the analysis of the time series allows us to determine the 24 hr rotational period of the planet for most observing geometries, due to large warm and cold areas, identified with geographic features, which appear consecutively in the observer's planetary view. However, the effects of global-scale meteorology can effectively mask the rotation for several days at a time. We also find that orbital time series exhibit a seasonal modulation, whose amplitude depends strongly on the latitude of the observer but weakly on its ecliptic longitude. As no systematic difference of brightness temperature is found between the dayside and the nightside, the phase variations of the Earth in the infrared range are negligible. Finally, we also conclude that the phase variation of a spatially unresolved Earth-Moon system is dominated by the lunar signal.

  3. Direct Reduction and Exact Solutions for Generalized Variable Coefficients 2D KdV Equation under Some Integrability Conditions

    NASA Astrophysics Data System (ADS)

    M. H. M., Moussa; Rehab, M. El-Shiekh

    2011-04-01

    Based on the closed connections among the homogeneous balance (HB) method and Clarkson—Kruskal (CK) method, we study the similarity reductions of the generalized variable coefficients 2D KdV equation. In the meantime it is shown that this leads to a direct reduction in the form of ordinary differential equation under some integrability conditions between the variable coefficients. Two different cases have been discussed, the search for solutions of those ordinary differential equations yielded many exact travelling and solitonic wave solutions in the form of hyperbolic and trigonometric functions under some constraints between the variable coefficients.

  4. Predicting ICT Integration into Classroom Teaching in Chinese Primary Schools: Exploring the Complex Interplay of Teacher-Related Variables

    ERIC Educational Resources Information Center

    Sang, Guoyuan; Valcke, Martin; van Braak, Johan; Tondeur, Jo; Zhu, Chang

    2011-01-01

    Available research has explored a wide variety of factors influencing information and communication technologies (ICT) adoption and integration in classroom teaching; however, existing research seldom centre on the combined impact of these variables. In addition, the little research available is set up in the Chinese context. The latter is…

  5. Integrating Spray Plane-Based Remote Sensing and Rapid Image Processing with Variable-Rate Aerial Application.

    USDA-ARS?s Scientific Manuscript database

    A remote sensing and variable rate application system was configured for agricultural aircraft. This combination system has the potential of providing a completely integrated solution for all aspects of aerial site-specific application and includes remote sensing, image processing and georegistratio...

  6. Predicting ICT Integration into Classroom Teaching in Chinese Primary Schools: Exploring the Complex Interplay of Teacher-Related Variables

    ERIC Educational Resources Information Center

    Sang, Guoyuan; Valcke, Martin; van Braak, Johan; Tondeur, Jo; Zhu, Chang

    2011-01-01

    Available research has explored a wide variety of factors influencing information and communication technologies (ICT) adoption and integration in classroom teaching; however, existing research seldom centre on the combined impact of these variables. In addition, the little research available is set up in the Chinese context. The latter is…

  7. Integrated approach to estimate the ocean's time variable dynamic topography including its covariance matrix

    NASA Astrophysics Data System (ADS)

    Müller, Silvia; Brockmann, Jan Martin; Schuh, Wolf-Dieter

    2015-04-01

    final product is accomplished. In conclusion, the developed integrated approach allows for estimating the dynamic topography and its inverse covariance matrix on arbitrary grids in space and time. The inverse covariance matrix contains the appropriate weights for model-data misfits in least-squares ocean model inversions. The focus of this study is on the North Atlantic Ocean. We will present the conceptual design and dynamic topography estimates based on time variable data from seven satellite altimeter missions (Jason-1, Jason-2, Topex/Poseidon, Envisat, ERS-2, GFO, Cryosat2) in combination with the latest GOCE gravity field model and in-situ data from the Argo floats and near-surface drifting buoys.

  8. An Integrative Framework for Bayesian Variable Selection with Informative Priors for Identifying Genes and Pathways

    PubMed Central

    Ander, Bradley P.; Zhang, Xiaoshuai; Xue, Fuzhong; Sharp, Frank R.; Yang, Xiaowei

    2013-01-01

    The discovery of genetic or genomic markers plays a central role in the development of personalized medicine. A notable challenge exists when dealing with the high dimensionality of the data sets, as thousands of genes or millions of genetic variants are collected on a relatively small number of subjects. Traditional gene-wise selection methods using univariate analyses face difficulty to incorporate correlational, structural, or functional structures amongst the molecular measures. For microarray gene expression data, we first summarize solutions in dealing with ‘large p, small n’ problems, and then propose an integrative Bayesian variable selection (iBVS) framework for simultaneously identifying causal or marker genes and regulatory pathways. A novel partial least squares (PLS) g-prior for iBVS is developed to allow the incorporation of prior knowledge on gene-gene interactions or functional relationships. From the point view of systems biology, iBVS enables user to directly target the joint effects of multiple genes and pathways in a hierarchical modeling diagram to predict disease status or phenotype. The estimated posterior selection probabilities offer probabilitic and biological interpretations. Both simulated data and a set of microarray data in predicting stroke status are used in validating the performance of iBVS in a Probit model with binary outcomes. iBVS offers a general framework for effective discovery of various molecular biomarkers by combining data-based statistics and knowledge-based priors. Guidelines on making posterior inferences, determining Bayesian significance levels, and improving computational efficiencies are also discussed. PMID:23844055

  9. Integrated MEMS-based variable optical attenuator and 10Gb/s receiver

    NASA Astrophysics Data System (ADS)

    Aberson, James; Cusin, Pierre; Fettig, H.; Hickey, Ryan; Wylde, James

    2005-03-01

    MEMS devices can be successfully commercialized in favour of competing technologies only if they offer an advantage to the customer in terms of lower cost or increased functionality. There are limited markets where MEMS can be manufactured cheaper than similar technologies due to large volumes: automotive, printing technology, wireless communications, etc. However, success in the marketplace can also be realized by adding significant value to a system at minimal cost or leverging MEMS technology when other solutions simply will not work. This paper describes a thermally actuated, MEMS based, variable optical attenuator that is co-packaged with existing opto-electronic devices to develop an integrated 10Gb/s SONET/SDH receiver. The configuration of the receiver opto-electronics and relatively low voltage availability (12V max) in optical systems bar the use of LCD, EO, and electro-chromic style attenuators. The device was designed and fabricated using a silicon-on-insulator (SOI) starting material. The design and performance of the device (displacement, power consumption, reliability, physical geometry) was defined by the receiver parameters geometry. This paper will describe how these design parameters (hence final device geometry) were determined in light of both the MEMS device fabrication process and the receiver performance. Reference will be made to the design tools used and the design flow which was a joint effort between the MEMS vendor and the end customer. The SOI technology offered a robust, manufacturable solution that gave the required performance in a cost-effective process. However, the singulation of the devices required the development of a new singulation technique that allowed large volumes of silicon to be removed during fabrication yet still offer high singulation yields.

  10. Variability in Clinical Integration Achieved by Athletic Training Students across Different Clinical Sport Assignments

    ERIC Educational Resources Information Center

    Dodge, Thomas M.; Mazerolle, Stephanie M.; Bowman, Thomas G.

    2015-01-01

    Context: Clinical integration impacts athletic training students' (ATSs) motivation and persistence. Research has yet to elucidate the manner in which different clinical placements can influence clinical integration. Objective: To examine differences in the levels of clinical integration achieved by ATSs across various clinical sport assignments.…

  11. Variability in Clinical Integration Achieved by Athletic Training Students across Different Clinical Sport Assignments

    ERIC Educational Resources Information Center

    Dodge, Thomas M.; Mazerolle, Stephanie M.; Bowman, Thomas G.

    2015-01-01

    Context: Clinical integration impacts athletic training students' (ATSs) motivation and persistence. Research has yet to elucidate the manner in which different clinical placements can influence clinical integration. Objective: To examine differences in the levels of clinical integration achieved by ATSs across various clinical sport assignments.…

  12. Prolonged exposure to high and variable phenylalanine levels over the lifetime predicts brain white matter integrity in children with phenylketonuria.

    PubMed

    Hood, Anna; Antenor-Dorsey, Jo Ann V; Rutlin, Jerrel; Hershey, Tamara; Shimony, Joshua S; McKinstry, Robert C; Grange, Dorothy K; Christ, Shawn E; Steiner, Robert; White, Desiree A

    2015-01-01

    In this study, we retrospectively examined the microstructural white matter integrity of children with early- and continuously-treated PKU (N=36) in relation to multiple indices of phenylalanine (Phe) control over the lifetime. White matter integrity was assessed using mean diffusivity (MD) from diffusion tensor imaging (DTI). Eight lifetime indices of Phe control were computed to reflect average Phe (mean, index of dietary control), variability in Phe (standard deviation, standard error of estimate, % spikes), change in Phe with age (slope), and prolonged exposure to Phe (mean exposure, standard deviation exposure). Of these indices, mean Phe, mean exposure, and standard deviation exposure were the most powerful predictors of widespread microstructural white matter integrity compromise. Findings from the two previously unexamined exposure indices reflected the accumulative effects of elevations and variability in Phe. Given that prolonged exposure to elevated and variable Phe was particularly detrimental to white matter integrity, Phe should be carefully monitored and controlled throughout childhood, without liberalization of Phe control as children with PKU age.

  13. Variables influencing the integrity of lower uterine segment in post-cesarean pregnancy.

    PubMed

    Brahmalakshmy, B L; Kushtagi, Pralhad

    2015-04-01

    There is significant increase in proportion of cases with previous cesarean delivery requiring obstetric care. The available literature fails to provide uniform opinion on each woman's characteristics to identify risk of uterine rupture while planning trial of labor after cesarean. To study the association of abnormal lower uterine segment with some of the present and previous obstetric variables including patient characteristics and surgical techniques at previous cesarean operation. Consenting consecutive 96 post-cesarean singleton pregnancies admitting after 36 weeks gestation at the same facility from July 2011 to December 2012 for repeat cesarean, were studied. Only the cases with cephalic presentation and vertex as presenting part, having no placenta previa, polyhydramnios, uterine anomaly or fibroid and those who had previous one lower segment cesarean were recruited. Based on the intra-operative finding the lower uterine segment (LUS) was categorized into those having a normal and abnormal (grades 2-4) LUS. Sonographic assessment of LUS thickness and any abnormalities if any were noted. The findings of abnormal LUS (direct observation at surgery and sonographic impression within a week before surgery) were looked for association with some of the present and previous obstetric variables including patient characteristics and surgical techniques at previous cesarean operation using Student t, Chi square or Fisher's exact test for analysis as appropriate. Receiver operating curve analysis was used to determine the optimal cut off value for prediction of LUS integrity by ultrasound. Of the women recruited for the study, 36 were admitted in early labor and ultrasound evaluation of LUS was performed in 48 of the remaining 60 women admitted antenatal for elective cesarean delivery. There were 38 abnormal LUS (39.6%) with 22 of them (57.9%) graded as 'thinned out LUS'. The incidence of scar dehiscence (grade 3, cases 5) was 5.2% of 96 cases and there were no cases

  14. Robust Integration Schemes for Generalized Viscoplasticity with Internal-State Variables

    NASA Technical Reports Server (NTRS)

    Saleeb, Atef F.; Li, W.; Wilt, Thomas E.

    1997-01-01

    The scope of the work in this presentation focuses on the development of algorithms for the integration of rate dependent constitutive equations. In view of their robustness; i.e., their superior stability and convergence properties for isotropic and anisotropic coupled viscoplastic-damage models, implicit integration schemes have been selected. This is the simplest in its class and is one of the most widely used implicit integrators at present.

  15. A comparison of surface air temperature variability in three 1000-Yr. coupled ocean-atmosphere model integrations

    SciTech Connect

    Stouffer, R.J.; Hegerl, G.; Tett, S.

    2000-02-01

    This study compares the variability of surface air temperature in three long coupled ocean-atmosphere general circulation model integrations. It is shown that the annual mean climatology of the surface air temperatures (SAT) in all three models is realistic and the linear trends over the 1,000-yr integrations are small over most areas of the globe. Second, although there are notable differences among the models, the models' SAT variability is fairly realistic on annual to decadal timescales, both in terms of the geographical distribution and of the global mean values. A notable exception is the poor simulation of observed tropical Pacific variability. In the HadCM2 model, the tropical variability is overestimated, while in the GFDL and HAM3L models, it is underestimated. Also, the ENSO-related spectral peak in the globally averaged observed SAT differs from that in any of the models. The relatively low resolution required to integrate models for long time periods inhibits the successful simulation of the variability in this region. On timescales longer than a few decades, the largest variance in the models is generally located near sea ice margins in high latitudes, which are also regions of deep oceanic convection and variability related to variations in the thermohaline circulation. However, the exact geographical location of these maxima varies from model to model. The preferred patterns of interdecadal variability that are common to all three coupled models can be isolated by computing empirical orthogonal functions (EOFs) of all model data simultaneously using the common EOF technique. A comparison of the variance each model associated with these common EOF patterns shows that the models generally agree on the most prominent patterns of variability. However, the amplitudes of the dominant models of variability differ to some extent between the models and between the models and observations. For example, two of the models have a mode with relatively large

  16. Nursing strategies to reduce length of stay for persons undergoing total knee replacement: integrative review of key variables.

    PubMed

    Hass, Shelly; Jaekel, Camilla; Nesbitt, Bonnie

    2015-01-01

    Decreasing the length of stay for persons undergoing total knee replacement surgery can improve patient and organizational outcomes while reducing health care costs. This integrative review examined selected nurse-driven variables that assist the interdisciplinary team to reduce length of stay. Findings suggest that a targeted clinical pathway including comprehensive preoperative patient education, physical therapy on the day of surgery, multimodal pain control, and proactive discharge planning may provide the best practice with this patient population.

  17. Grid Integration and the Carrying Capacity of the U.S. Grid to Incorporate Variable Renewable Energy

    SciTech Connect

    Cochran, Jaquelin; Denholm, Paul; Speer, Bethany; Miller, Mackay

    2015-04-23

    In the United States and elsewhere, renewable energy (RE) generation supplies an increasingly large percentage of annual demand, including nine U.S. states where wind comprised over 10% of in-state generation in 2013. This white paper summarizes the challenges to integrating increasing amounts of variable RE, identifies emerging practices in power system planning and operation that can facilitate grid integration, and proposes a unifying concept—economic carrying capacity—that can provide a framework for evaluating actions to accommodate higher penetrations of RE. There is growing recognition that while technical challenges to variable RE integration are real, they can generally be addressed via a variety of solutions that vary in implementation cost. As a result, limits to RE penetration are primarily economic, driven by factors that include transmission and the flexibility of the power grid to balance supply and demand. This limit can be expressed as economic carrying capacity, or the point at which variable RE is no longer economically competitive or desirable to the system or society.

  18. Silica-based, compact and variable-optical-attenuator integrated coherent receiver with stable optoelectronic coupling system.

    PubMed

    Tsunashima, Satoshi; Nakajima, Fumito; Nasu, Yusuke; Kasahara, Ryoichi; Nakanishi, Yasuhiko; Saida, Takashi; Yamada, Takashi; Sano, Kimikazu; Hashimoto, Toshikazu; Fukuyama, Hiroyuki; Nosaka, Hideaki; Murata, Koichi

    2012-11-19

    We demonstrate a compact and variable-optical-attenuator (VOA) integrated coherent receiver with a silica-based planar lightwave circuit (PLC). To realize the compact receiver, we integrate a VOA in a single PLC chip with polarization beam splitters and optical 90-degree hybrids, and employ a stable optoelectronic coupling system consisting of micro lens arrays and photodiode (PD) subcarriers with high-speed right-angled signal lines. We integrate a VOA and a coherent receiver in a 27x40x6 mm package, and successfully demodulate a 128-Gbit/s polarization division multiplexed (PDM) quadrature phase shift keying (QPSK) signal with a VOA-assisted wide dynamic range of more than 30 dB.

  19. Neural dynamics of audiovisual speech integration under variable listening conditions: an individual participant analysis

    PubMed Central

    Altieri, Nicholas; Wenger, Michael J.

    2013-01-01

    Speech perception engages both auditory and visual modalities. Limitations of traditional accuracy-only approaches in the investigation of audiovisual speech perception have motivated the use of new methodologies. In an audiovisual speech identification task, we utilized capacity (Townsend and Nozawa, 1995), a dynamic measure of efficiency, to quantify audiovisual integration. Capacity was used to compare RT distributions from audiovisual trials to RT distributions from auditory-only and visual-only trials across three listening conditions: clear auditory signal, S/N ratio of −12 dB, and S/N ratio of −18 dB. The purpose was to obtain EEG recordings in conjunction with capacity to investigate how a late ERP co-varies with integration efficiency. Results showed efficient audiovisual integration for low auditory S/N ratios, but inefficient audiovisual integration when the auditory signal was clear. The ERP analyses showed evidence for greater audiovisual amplitude compared to the unisensory signals for lower auditory S/N ratios (higher capacity/efficiency) compared to the high S/N ratio (low capacity/inefficient integration). The data are consistent with an interactive framework of integration, where auditory recognition is influenced by speech-reading as a function of signal clarity. PMID:24058358

  20. Implementation of a Variable Stepsize Variable Formula Method in the Time-Integration Part of a Code for Treatment of Long-Range Transport of Air Pollutants

    NASA Astrophysics Data System (ADS)

    Zlatev, Zahari; Berkowicz, Ruwim; Prahm, Lars P.

    1984-08-01

    A mathematical model consisting of two partial differential equations is used to study the long-range transport of sulphur di-oxide and sulphate over Europe. The discretization of the first-order space derivatives ( the advection terms) is carried out by a pseudospectral (Fourier) algorithm. A special technique is applied in the discretization of the second-order space derivatives ( the diffusion terms). Two large systems of ordinary differential equations are solved at each time-step. It is shown that these systems can efficiently be treated by a variable stepsize variable formula method (VSVFM) based on the use of predictor-corrector schemes. The stepsize selection strategy and the formula selection strategy are discussed in detail. An attempt to carry out both an accuracy control and a stability control is made at each time-step. The great efficiency of the VSVFM implemented in our software as well as the reliability of the results are illustrated by numerical experiments, in which real meteorological data (for 1979) at the grid-points of a space domain covering the whole of Europe were used. The main ideas, implemented in the time-integration part, might be applied in many other situations, where the systems of ordinary differential equations arising after the space discretization are only moderately stiff (so that the stability requirements are dominant over the accuracy requirements on a large part of the time-interval but the use of implicit time-integration algorithms that require solving systems of algebraic equations at each time-step is not justified). As an illustration only it should be mentioned that such an application has been carried out in connection with models describing long-range transport of nitrogen pollutants over Europe.

  1. Integrating biological knowledge into variable selection: an empirical Bayes approach with an application in cancer biology

    PubMed Central

    2012-01-01

    Background An important question in the analysis of biochemical data is that of identifying subsets of molecular variables that may jointly influence a biological response. Statistical variable selection methods have been widely used for this purpose. In many settings, it may be important to incorporate ancillary biological information concerning the variables of interest. Pathway and network maps are one example of a source of such information. However, although ancillary information is increasingly available, it is not always clear how it should be used nor how it should be weighted in relation to primary data. Results We put forward an approach in which biological knowledge is incorporated using informative prior distributions over variable subsets, with prior information selected and weighted in an automated, objective manner using an empirical Bayes formulation. We employ continuous, linear models with interaction terms and exploit biochemically-motivated sparsity constraints to permit exact inference. We show an example of priors for pathway- and network-based information and illustrate our proposed method on both synthetic response data and by an application to cancer drug response data. Comparisons are also made to alternative Bayesian and frequentist penalised-likelihood methods for incorporating network-based information. Conclusions The empirical Bayes method proposed here can aid prior elicitation for Bayesian variable selection studies and help to guard against mis-specification of priors. Empirical Bayes, together with the proposed pathway-based priors, results in an approach with a competitive variable selection performance. In addition, the overall procedure is fast, deterministic, and has very few user-set parameters, yet is capable of capturing interplay between molecular players. The approach presented is general and readily applicable in any setting with multiple sources of biological prior knowledge. PMID:22578440

  2. Integrating biological knowledge into variable selection: an empirical Bayes approach with an application in cancer biology.

    PubMed

    Hill, Steven M; Neve, Richard M; Bayani, Nora; Kuo, Wen-Lin; Ziyad, Safiyyah; Spellman, Paul T; Gray, Joe W; Mukherjee, Sach

    2012-05-11

    An important question in the analysis of biochemical data is that of identifying subsets of molecular variables that may jointly influence a biological response. Statistical variable selection methods have been widely used for this purpose. In many settings, it may be important to incorporate ancillary biological information concerning the variables of interest. Pathway and network maps are one example of a source of such information. However, although ancillary information is increasingly available, it is not always clear how it should be used nor how it should be weighted in relation to primary data. We put forward an approach in which biological knowledge is incorporated using informative prior distributions over variable subsets, with prior information selected and weighted in an automated, objective manner using an empirical Bayes formulation. We employ continuous, linear models with interaction terms and exploit biochemically-motivated sparsity constraints to permit exact inference. We show an example of priors for pathway- and network-based information and illustrate our proposed method on both synthetic response data and by an application to cancer drug response data. Comparisons are also made to alternative Bayesian and frequentist penalised-likelihood methods for incorporating network-based information. The empirical Bayes method proposed here can aid prior elicitation for Bayesian variable selection studies and help to guard against mis-specification of priors. Empirical Bayes, together with the proposed pathway-based priors, results in an approach with a competitive variable selection performance. In addition, the overall procedure is fast, deterministic, and has very few user-set parameters, yet is capable of capturing interplay between molecular players. The approach presented is general and readily applicable in any setting with multiple sources of biological prior knowledge.

  3. Effect of Integrated Yoga Module on Selected Psychological Variables among Women with Anxiety Problem.

    PubMed

    Parthasarathy, S; Jaiganesh, K; Duraisamy

    2014-01-01

    The implementation of yogic practices has proven benefits in both organic and psychological diseases. Forty-five women with anxiety selected by a random sampling method were divided into three groups. Experimental group I was subjected to asanas, relaxation and pranayama while Experimental group II was subjected to an integrated yoga module. The control group did not receive any intervention. Anxiety was measured by Taylor's Manifest Anxiety Scale before and after treatment. Frustration was measured through Reaction to Frustration Scale. All data were spread in an Excel sheet to be analysed with SPSS 16 software using analysis of covariance (ANCOVA). Selected yoga and asanas decreased anxiety and frustration scores but treatment with an integrated yoga module resulted in significant reduction of anxiety and frustration. To conclude, the practice of asanas and yoga decreased anxiety in women, and yoga as an integrated module significantly improved anxiety scores in young women with proven anxiety without any ill effects.

  4. Understanding Variability and Uncertainty of Photovoltaics for Integration with the Electric Power System

    SciTech Connect

    Mills, Andrew; Ahlstrom, Mark; Brower, Michael; Ellis, Abraham; George, Ray; Hoff, Tom; Kroposki, Benjamin; Lenox, Carl; Miller, Nicholas; Stein, Joshua; Wan, Yih-huei

    2009-12-07

    Data and analysis are needed to understand the variability of photovoltaic (PV) plants to avoid unnecessary barriers to the interconnection of PV. Several datasets show clouds can cause rapid changes in solar insolation. Smoothing of rapid ramps, however, occurs within PV plants. The degree of smoothing depends on plant size. Smoothing occurs on even longer time-scales between separate plants.

  5. Students, Teachers, and Schools as Sources of Variability, Integrity, and Sustainability in Implementing Progress Monitoring

    ERIC Educational Resources Information Center

    Bolt, Daniel M.; Ysseldyke, Jim; Patterson, Michael J.

    2010-01-01

    A three-level variance decomposition analysis was used to examine the sources of variability in implementation of a technology-enhanced progress monitoring system within each year of a 2-year study using a randomized-controlled design. We show that results of technology-enhanced progress monitoring are not necessarily a measure of student…

  6. Integration of variable-rate OWC with OFDM-PON for hybrid optical access based on adaptive envelope modulation

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Zhong, Wen-De; Wu, Dehao

    2016-12-01

    In this paper, we investigate an integrated optical wireless communication (OWC) and orthogonal frequency division multiplexing based passive optical network (OFDM-PON) system for hybrid wired and wireless optical access, based on an adaptive envelope modulation technique. Both the outdoor and indoor wireless communications are considered in the integrated system. The data for wired access is carried by a conventional OFDM signal, while the data for wireless access is carried by an M-ary pulse amplitude modulation (M-PAM) signal which is modulated onto the envelope of a phase-modulated OFDM signal. By adaptively modulating the wireless M-PAM signal onto the envelope of the wired phase-modulated constant envelope OFDM (CE-OFDM) signal, hybrid wired and wireless optical access can be seamlessly integrated and variable-rate optical wireless transmission can also be achieved. Analytical bit-error-rate (BER) expressions are derived for both the CE-OFDM signal with M-PAM overlay and the overlaid unipolar M-PAM signal, which are verified by Monte Carlo simulations. The BER performances of wired access, indoor OWC wireless access and outdoor OWC wireless access are evaluated. Moreover, variable-rate indoor and outdoor optical wireless access based on the adaptive envelope modulation technique is also discussed.

  7. Variables that Affect Math Teacher Candidates' Intentions to Integrate Computer-Assisted Mathematics Education (CAME)

    ERIC Educational Resources Information Center

    Erdogan, Ahmet

    2010-01-01

    Based on Social Cognitive Carier Theory (SCCT) (Lent, Brown, & Hackett, 1994, 2002), this study tested the effects of mathematics teacher candidates' self-efficacy in, outcome expectations from, and interest in CAME on their intentions to integrate Computer-Assisted Mathematics Education (CAME). While mathematics teacher candidates' outcome…

  8. Mean convergence theorems and weak laws of large numbers for weighted sums of random variables under a condition of weighted integrability

    NASA Astrophysics Data System (ADS)

    Ordóñez Cabrera, Manuel; Volodin, Andrei I.

    2005-05-01

    From the classical notion of uniform integrability of a sequence of random variables, a new concept of integrability (called h-integrability) is introduced for an array of random variables, concerning an array of constantsE We prove that this concept is weaker than other previous related notions of integrability, such as Cesàro uniform integrability [Chandra, Sankhya Ser. A 51 (1989) 309-317], uniform integrability concerning the weights [Ordóñez Cabrera, Collect. Math. 45 (1994) 121-132] and Cesàro [alpha]-integrability [Chandra and Goswami, J. Theoret. ProbabE 16 (2003) 655-669]. Under this condition of integrability and appropriate conditions on the array of weights, mean convergence theorems and weak laws of large numbers for weighted sums of an array of random variables are obtained when the random variables are subject to some special kinds of dependence: (a) rowwise pairwise negative dependence, (b) rowwise pairwise non-positive correlation, (c) when the sequence of random variables in every row is [phi]-mixing. Finally, we consider the general weak law of large numbers in the sense of Gut [Statist. Probab. Lett. 14 (1992) 49-52] under this new condition of integrability for a Banach space setting.

  9. An Integrated Method to Analyze Farm Vulnerability to Climatic and Economic Variability According to Farm Configurations and Farmers' Adaptations.

    PubMed

    Martin, Guillaume; Magne, Marie-Angélina; Cristobal, Magali San

    2017-01-01

    The need to adapt to decrease farm vulnerability to adverse contextual events has been extensively discussed on a theoretical basis. We developed an integrated and operational method to assess farm vulnerability to multiple and interacting contextual changes and explain how this vulnerability can best be reduced according to farm configurations and farmers' technical adaptations over time. Our method considers farm vulnerability as a function of the raw measurements of vulnerability variables (e.g., economic efficiency of production), the slope of the linear regression of these measurements over time, and the residuals of this linear regression. The last two are extracted from linear mixed models considering a random regression coefficient (an intercept common to all farms), a global trend (a slope common to all farms), a random deviation from the general mean for each farm, and a random deviation from the general trend for each farm. Among all possible combinations, the lowest farm vulnerability is obtained through a combination of high values of measurements, a stable or increasing trend and low variability for all vulnerability variables considered. Our method enables relating the measurements, trends and residuals of vulnerability variables to explanatory variables that illustrate farm exposure to climatic and economic variability, initial farm configurations and farmers' technical adaptations over time. We applied our method to 19 cattle (beef, dairy, and mixed) farms over the period 2008-2013. Selected vulnerability variables, i.e., farm productivity and economic efficiency, varied greatly among cattle farms and across years, with means ranging from 43.0 to 270.0 kg protein/ha and 29.4-66.0% efficiency, respectively. No farm had a high level, stable or increasing trend and low residuals for both farm productivity and economic efficiency of production. Thus, the least vulnerable farms represented a compromise among measurement value, trend, and variability of

  10. An Integrated Method to Analyze Farm Vulnerability to Climatic and Economic Variability According to Farm Configurations and Farmers’ Adaptations

    PubMed Central

    Martin, Guillaume; Magne, Marie-Angélina; Cristobal, Magali San

    2017-01-01

    The need to adapt to decrease farm vulnerability to adverse contextual events has been extensively discussed on a theoretical basis. We developed an integrated and operational method to assess farm vulnerability to multiple and interacting contextual changes and explain how this vulnerability can best be reduced according to farm configurations and farmers’ technical adaptations over time. Our method considers farm vulnerability as a function of the raw measurements of vulnerability variables (e.g., economic efficiency of production), the slope of the linear regression of these measurements over time, and the residuals of this linear regression. The last two are extracted from linear mixed models considering a random regression coefficient (an intercept common to all farms), a global trend (a slope common to all farms), a random deviation from the general mean for each farm, and a random deviation from the general trend for each farm. Among all possible combinations, the lowest farm vulnerability is obtained through a combination of high values of measurements, a stable or increasing trend and low variability for all vulnerability variables considered. Our method enables relating the measurements, trends and residuals of vulnerability variables to explanatory variables that illustrate farm exposure to climatic and economic variability, initial farm configurations and farmers’ technical adaptations over time. We applied our method to 19 cattle (beef, dairy, and mixed) farms over the period 2008–2013. Selected vulnerability variables, i.e., farm productivity and economic efficiency, varied greatly among cattle farms and across years, with means ranging from 43.0 to 270.0 kg protein/ha and 29.4–66.0% efficiency, respectively. No farm had a high level, stable or increasing trend and low residuals for both farm productivity and economic efficiency of production. Thus, the least vulnerable farms represented a compromise among measurement value, trend, and

  11. Solitons and integrability for a (2+1)-dimensional generalized variable-coefficient shallow water wave equation

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Le; Gao, Yi-Tian; Jia, Shu-Liang; Lan, Zhong-Zhou; Deng, Gao-Fu; Su, Jing-Jing

    2017-01-01

    Under investigation in this paper is a (2+1)-dimensional generalized variable-coefficient shallow water wave equation which can be reduced to several integrable equations, such as the Korteweg-de Vries (KdV) equation and the Calogero-Bogoyavlenskii-Schiff (CBS) equation. Bilinear forms, Bäcklund transformation, Lax pair and infinite conservation laws are derived based on the binary Bell polynomials. N-soliton solutions are constructed via the Hirota method. Propagation and interaction of the solitons are illustrated graphically: (i) variable coefficients affect the shape of the N-soliton interaction in the scaled space and time coordinates; (ii) positions of the solitons depend on the sign of wave numbers after each interaction; (iii) interaction of the solitons is elastic, i.e. the amplitude, velocity and shape of each soliton remain invariant after each interaction except for a phase shift.

  12. Application of the time-delay integration method: Survey observations of geosynchronous orbit objects and short-term variability observations

    NASA Astrophysics Data System (ADS)

    Okumura, Shin-ichiro; Yanagisawa, Toshifumi; Nakaya, Hidehiko; Tanaka, Wataru; Nishiyama, Kota; Takahashi, Noritsugu; Yoshikawa, Makoto

    2014-12-01

    "Time-Delay Integration (TDI)" readout technique has been adopted to a mosaic CCD camera equipped with four fully-depleted CCDs. Optical distortion and image deformation due to the TDI operation are discussed. The manner and advantages of the TDI method in survey observations of geosynchronous orbit objects are summarized. We propose a new TDI application method of getting short-term light curves of artificial space objects. This method of detecting a short-term variability can be applied for a variety of objects, ranging from satellites to stars. It can also be used for the light-curve observations of transient objects which might show short-term variability and of which the precise time information is needed.

  13. Global Variability of Light Use Efficiency: a Model Data Integration Approach

    NASA Astrophysics Data System (ADS)

    Tomelleri, E.; Reichstein, M.; Papale, D.; Beer, C.

    2007-12-01

    Estimating the present global gross primary production (GPP) and giving reliable future predictions is one of the major challenges of carbon cycle research. Light-use efficiency (LUE) algorithms are a potentially effective approach for monitoring global primary production (GPP) using satellite-borne sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS). Their advantage is that all the drivers can be easily derived from remote sensed data or from existing climate observation networks offering a number of opportunities for up- scaling approaches. These algorithms are applied at relatively wide geographical areas, which may subsume significant heterogeneity in vegetation LUEmax and, hence, introduce error. However, data on the variability of the LUEmax coefficient, are scarce, often derived from leaf-level or NPP measurements and sometimes conflicting. A solution to this problem is to estimate the this physiological parameter inverting the algorithm against eddy covariance derived measurements of GPP, that are now globally available in a consistent format. Hence, the objective of this study is to fill this gap by means of quantifying and compare the variability of LUEmax and its sensitivity to environmental conditions among plant vegetation types. For this purpose, we optimized the MOD17 algorithm against the GPP time series from the FLUXNET measurement network. In doing this, we made a Bayesian data model synthesis by means of the Metropolis-Hastings algorithm. The LUEmax values from the BPLUT lookup table in the MOD17 user's manual were used as prior. The uncertainties in flux data were characterized specifically site by site. The parameter estimation considerably increased LUEmax for vegetation types with a short leaf-life while for evergreen vegetation types a posteriori parameter values were lower than the a priori ones. These optimized a posteriori values open different research questions regarding the uses of this model at wide geographical

  14. Integrating spatial and temporal variability into the analysis of fish food web linkages in Tijuana Estuary.

    SciTech Connect

    West, Janelle M.; Williams, Greg D.; Madon, Sharook P.; Zedler, Joy B.

    2003-05-14

    Our understanding of fish feeding interactions at Tijuana Estuary was improved by incorporating estimates of spatial and temporal variability into diet analyses. We examined the stomach contents of 7 dominant species (n=579 total fish) collected between 1994 and 1999. General feeding patterns pooled over time produced a basic food web consisting of 3 major trophic levels: (1) primary consumers (Atherinops affinis, Mugil cephalus) that ingested substantial amounts of plant material and detritus; (2) benthic carnivores (Clevelandia ios, Hypsopsetta guttulata, Gillichthys mirabilis, and Fundulus parvipinnis) that ingested high numbers of calanoid copepods and exotic amphipods (Grandidierella japonica); and (3) piscivores (Paralichthys californicus and Leptocottus armatus) that often preyed on smaller gobiids. Similarity-based groupings of individual species' diets were identified using nonmetric multidimensional scaling to characterize their variability within and between species, and in s pace and time. This allowed us to identify major shifts and recognize events (i.e., modified prey abundance during 1997-98 El Nino floods) that likely caused these shifts.

  15. Interarea Power System Oscillations Damping via AI-based Referential Integrity Variable-Structure Control

    NASA Astrophysics Data System (ADS)

    Ebrahim, M. A.; Ramadan, H. S.

    2016-10-01

    The design of power system stabilizer (PSS) is load-dependent and needs continuous adjustment at each operating condition. This paper aims at introducing a robust non-fragile PSS for interconnected power systems. The proposed controller has the capability of adaptively tuning online its rule-base through a variable-structure direct adaptive control algorithm in order to rigorously attain the desired objectives. The PSS controller acts on damping the electromechanical modes of oscillations not only through a wide range of operating conditions but also in presence of different disturbances. Using MATLABTM-Simulink, simulation results significantly verify that the proposed controller provides favorable performance and efficiently contributes towards enhancing the system dynamic behavior when applied to the four machines two-area power system that mimics the typical system behavior in actual operation. The interaction between the variable-structure adaptive fuzzy-based power system stabilizer (VS-AFPSS) and the existed typical ones inside the interconnected power systems has been explicitly discussed. Compared to other conventional controllers, VS-AFPSS enables better damping characteristics to both local and inter-area oscillation modes considering different operating conditions and sever disturbances.

  16. Integration of Variable Speed Pumped Hydro Storage in Automatic Generation Control Systems

    NASA Astrophysics Data System (ADS)

    Fulgêncio, N.; Moreira, C.; Silva, B.

    2017-04-01

    Pumped storage power (PSP) plants are expected to be an important player in modern electrical power systems when dealing with increasing shares of new renewable energies (NRE) such as solar or wind power. The massive penetration of NRE and consequent replacement of conventional synchronous units will significantly affect the controllability of the system. In order to evaluate the capability of variable speed PSP plants participation in the frequency restoration reserve (FRR) provision, taking into account the expected performance in terms of improved ramp response capability, a comparison with conventional hydro units is presented. In order to address this issue, a three area test network was considered, as well as the corresponding automatic generation control (AGC) systems, being responsible for re-dispatching the generation units to re-establish power interchange between areas as well as the system nominal frequency. The main issue under analysis in this paper is related to the benefits of the fast response of variable speed PSP with respect to its capability of providing fast power balancing in a control area.

  17. Glucocorticoid assessment in the domestic horse: the impact of time and climatic variables on sample integrity.

    PubMed

    Yarnell, K; Walker, S L

    2017-07-20

    Assessment of faecal glucocorticoid metabolites (FGM) offers a non-invasive method of monitoring adrenal activity in domestic horses. Sample collection is on an opportunistic basis, and if samples are not fresh or have been exposed to the elements before they are identified, then they may not accurately reflect FGM concentration. To explore the impact of a range of environmental conditions upon the integrity of FGM levels in equine faeces. In vitro experiment. Equine faeces were exposed to six controlled environmental conditions meant to simulate a range of weather and seasonal patterns (temperate climate, high heat, high heat and rainfall, temperate climate and rainfall, high heat/temperate climate and freeze/thaw) over a period of five days. FGM were quantified using an enzyme linked immunoassay. Faecal samples exposed to room temperature and high heat demonstrated a significant increase in FGM over time. Changes in FGM were not observed in the remaining treatments. The study should be repeated in field conditions and with known high and low levels of FGM to further inform sampling regimes. Adrenal monitoring in the domestic horse should be performed with consideration of the impact of climate on integrity of faecal samples to further inform sampling schedules and improve reliability of results. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. The association between higher order abilities, processing speed, and age are variably mediated by white matter integrity during typical aging

    PubMed Central

    Borghesani, Paul R.; Madhyastha, Tara M; Aylward, Elizabeth H.; Reiter, Maya A.; Swarny, Bruce R.; Schaie, K. Warner; Willis, Sherry L

    2013-01-01

    Although aging is associated with changes in brain structure and cognition it remains unclear which specific structural changes mediate individual cognitive changes. Several studies have reported that white matter (WM) integrity, as assessed by diffusion tensor imaging (DTI), mediates, in part, age-related differences in processing speed (PS). There is less evidence for WM integrity mediating age-related differences in higher order abilities (e.g., memory and executive functions). In 165 typically aging adults (age range 54–89) we show that WM integrity in select cerebral regions is associated with higher cognitive abilities and accounts variance not accounted for by PS or age. Specifically, voxel-wise analyses using tract-based spatial statistics (TBSS) revealed that WM integrity was associated with reasoning, cognitive flexibility and PS, but not memory or word fluency, after accounting for age and gender. While cerebral fractional anisotropy (FA) was only associated with PS; mean (MD), axial (AD) and radial (RD) diffusivity were associated with reasoning and flexibility. Reasoning was selectively associated with left prefrontal AD, while cognitive flexibility was associated with MD, AD and RD throughout the cerebrum. Average WM metrics within select WM regions of interest accounted for 18% and 29% of the variance in reasoning and flexibility, respectively, similar to the amount of variance accounted for by age. WM metrics mediated ~50% of the age-related variance in reasoning and flexibility and different proportions, 11% for reasoning and 44% for flexibility, of the variance accounted for by PS. In sum, i) WM integrity is significantly, but variably, related to specific higher cognitive abilities and can account for a similar proportion of variance as age, and ii) while FA is selectively associated with PS; while MD, AD and RD are associated with reasoning, flexibility and PS. This illustrates both the anatomical and cognitive selectivity of structure

  19. Understanding the Longitudinal Variability of Equatorial Electrodynamics using integrated Ground- and Space-based Observations

    NASA Astrophysics Data System (ADS)

    Yizengaw, E.; Moldwin, M.; Zesta, E.

    2015-12-01

    The currently funded African Meridian B-Field Education and Research (AMBER) magnetometer array comprises more than thirteen magnetometers stationed globally in the vicinity of geomagnetic equator. One of the main objectives of AMBER network is to understand the longitudinal variability of equatorial electrodynamics as function of local time, magnetic activity, and season. While providing complete meridian observation in the region and filling the largest land-based gap in global magnetometer coverage, the AMBER array addresses two fundamental areas of space physics: first, the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and second, ULF pulsation strength at low/mid-latitude regions and its connection with equatorial electrojet and density fluctuation. The global AMBER network can also be used to augment observations from space-based instruments, such us the triplet SWARM mission and the upcoming ICON missions. Thus, in coordination with space-based and other ground-based observations, the AMBER magnetometer network provides a great opportunity to understand the electrodynamics that governs equatorial ionosphere motions. In this paper we present the longitudinal variability of the equatorial electrodynamics using the combination of instruments onboard SWARM and C/NOFS satellites and ground-based AMBER network. Both ground- and pace-based observations show stronger dayside and evening sector equatorial electrodynamics in the American and Asian sectors compared to the African sector. On the other hand, the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This raises the question if the evening sector equatorial electrodynamics (vertical drift), which is believed to be the main cause for the enhancement of Rayleigh-Taylor (RT) instability growth rate, is stronger in the

  20. Integrated assessment of the spatial variability of ozone impacts from emissions of nitrogen oxides.

    PubMed

    Tong, Daniel Q; Muller, Nicholas Z; Mauzerall, Denise L; Mendelsohn, Robert O

    2006-03-01

    This paper examines the ozone (O3) damages caused by nitrogen oxides (NO(x)) emissions in different locations around the Atlanta metropolitan area during a summer month. We calculate O3 impacts using a new integrated assessment model that links pollution emissions to their chemical transformation, transport, population exposures, and effects on human health. We find that increased NO(x) emissions in rural areas around Atlanta increase human exposure to ambient O3 twice as much as suburban emissions. However, increased NO(x) emissions in central city Atlanta actually reduce O3 exposures. For downtown emissions, the reduction in human exposures to O3 from titration by NO in the central city outweighs the effects from increased downwind O3. The results indicate that the marginal damage from NO(x) emissions varies greatly across a metropolitan area. The results raise concerns if cap and trade regulations cause emissions to migrate toward higher marginal damage locations.

  1. Integrated Central-Autonomic Multifractal Complexity in the Heart Rate Variability of Healthy Humans

    PubMed Central

    Lin, D. C.; Sharif, A.

    2012-01-01

    Purpose of Study: The aim of this study was to characterize the central-autonomic interaction underlying the multifractality in heart rate variability (HRV) of healthy humans. Materials and Methods: Eleven young healthy subjects participated in two separate ~40 min experimental sessions, one in supine (SUP) and one in, head-up-tilt (HUT), upright (UPR) body positions. Surface scalp electroencephalography (EEG) and electrocardiogram (ECG) were collected and fractal correlation of brain and heart rate data was analyzed based on the idea of relative multifractality. The fractal correlation was further examined with the EEG, HRV spectral measures using linear regression of two variables and principal component analysis (PCA) to find clues for the physiological processing underlying the central influence in fractal HRV. Results: We report evidence of a central-autonomic fractal correlation (CAFC) where the HRV multifractal complexity varies significantly with the fractal correlation between the heart rate and brain data (P = 0.003). The linear regression shows significant correlation between CAFC measure and EEG Beta band spectral component (P = 0.01 for SUP and P = 0.002 for UPR positions). There is significant correlation between CAFC measure and HRV LF component in the SUP position (P = 0.04), whereas the correlation with the HRV HF component approaches significance (P = 0.07). The correlation between CAFC measure and HRV spectral measures in the UPR position is weak. The PCA results confirm these findings and further imply multiple physiological processes underlying CAFC, highlighting the importance of the EEG Alpha, Beta band, and the HRV LF, HF spectral measures in the supine position. Discussion and Conclusion: The findings of this work can be summarized into three points: (i) Similar fractal characteristics exist in the brain and heart rate fluctuation and the change toward stronger fractal correlation implies the change toward more complex

  2. Active flow control integrated diffuser (afcid) for increased energy efficiency in variable air volume systems

    NASA Astrophysics Data System (ADS)

    Van Der Schijff, Hermanus P.

    Variable air volume (VAV) air terminals are designed to save energy by reducing airflow into a given space based on occupancy and required load. Systems are typically designed to operate at peak load, however as load is reduced, performance is compromised due to inadequate throw. As a result, fans are installed to adjust for the losses, negating many of the energy savings. Additionally flow is vectored by the use of vanes, a basic passive type of flow control. An experimental investigation was performed to study the application of flow control on that of a HVAC diffuser using synthetic jets distributed evenly along the diffuser edge parallel to the flow field. The study was conducted on a 1:3 scale typical office space (150 ft2), which included a simulated scale HVAC system supplied by compressed air. Two different jet blowing ratios were investigated for system loads of 60% and 90%. The flow field was established using hot wire anemometry and Particle Image Velocimetry (PIV). This study demonstrates the effectiveness of synthetic jet based active flow control at controlling airflow, showing ability to affect throw parameters for changing flow rates within the test chamber. Vectoring of up to 20% and improvement in jet spread of 200% was demonstrated. The use of such devices has the potential to improve air quality and air distribution in building while simultaneously lowering energy demands of HVAC systems.

  3. Using Conventional Hydropower to Help Alleviate Variable Resource Grid Integration Challenges in the Western U.S

    NASA Astrophysics Data System (ADS)

    Veselka, T. D.; Poch, L.

    2011-12-01

    Integrating high penetration levels of wind and solar energy resources into the power grid is a formidable challenge in virtually all interconnected systems due to the fact that supply and demand must remain in balance at all times. Since large scale electricity storage is currently not economically viable, generation must exactly match electricity demand plus energy losses in the system as time unfolds. Therefore, as generation from variable resources such as wind and solar fluctuate, production from generating resources that are easier to control and dispatch need to compensate for these fluctuations while at the same time respond to both instantaneous change in load and follow daily load profiles. The grid in the Western U.S. is not exempt to grid integration challenges associated with variable resources. However, one advantage that the power system in the Western U.S. has over many other regional power systems is that its footprint contains an abundance of hydropower resources. Hydropower plants, especially those that have reservoir water storage, can physically change electricity production levels very quickly both via a dispatcher and through automatic generation control. Since hydropower response time is typically much faster than other dispatchable resources such as steam or gas turbines, it is well suited to alleviate variable resource grid integration issues. However, despite an abundance of hydropower resources and the current low penetration of variable resources in the Western U.S., problems have already surfaced. This spring in the Pacific Northwest, wetter than normal hydropower conditions in combination with transmission constraints resulted in controversial wind resource shedding. This action was taken since water spilling would have increased dissolved oxygen levels downstream of dams thereby significantly degrading fish habitats. The extent to which hydropower resources will be able to contribute toward a stable and reliable Western grid is

  4. The surface temperatures of Earth: steps towards integrated understanding of variability and change

    NASA Astrophysics Data System (ADS)

    Merchant, C. J.; Matthiesen, S.; Rayner, N. A.; Remedios, J. J.; Jones, P. D.; Olesen, F.; Trewin, B.; Thorne, P. W.; Auchmann, R.; Corlett, G. K.; Guillevic, P. C.; Hulley, G. C.

    2013-12-01

    Surface temperature is a key aspect of weather and climate, but the term may refer to different quantities that play interconnected roles and are observed by different means. In a community-based activity in June 2012, the EarthTemp Network brought together 55 researchers from five continents to improve the interaction between scientific communities who focus on surface temperature in particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities. The workshop identified key needs for progress towards meeting scientific and societal requirements for surface temperature understanding and information, which are presented in this community paper. A "whole-Earth" perspective is required with more integrated, collaborative approaches to observing and understanding Earth's various surface temperatures. It is necessary to build understanding of the relationships between different surface temperatures, where presently inadequate, and undertake large-scale systematic intercomparisons. Datasets need to be easier to obtain and exploit for a wide constituency of users, with the differences and complementarities communicated in readily understood terms, and realistic and consistent uncertainty information provided. Steps were also recommended to curate and make available data that are presently inaccessible, develop new observing systems and build capacities to accelerate progress in the accuracy and usability of surface temperature datasets.

  5. The surface temperatures of the earth: steps towards integrated understanding of variability and change

    NASA Astrophysics Data System (ADS)

    Merchant, C. J.; Matthiesen, S.; Rayner, N. A.; Remedios, J. J.; Jones, P. D.; Olesen, F.; Trewin, B.; Thorne, P. W.; Auchmann, R.; Corlett, G. K.; Guillevic, P. C.; Hulley, G. C.

    2013-06-01

    Surface temperature is a key aspect of weather and climate, but the term may refer to different quantities that play interconnected roles and are observed by different means. In a community-based activity in June 2012, the EarthTemp Network brought together 55 researchers from five continents to improve the interaction between scientific communities who focus on surface temperature in particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities. The workshop identified key needs for progress towards meeting scientific and societal requirements for surface temperature understanding and information which are presented in this community paper. A "whole-Earth" perspective is required with more integrated, collaborative approaches to observing and understanding Earth's various surface temperatures. It is necessary to build understanding of the relationships between different surface temperatures, where presently inadequate, and undertake large-scale systematic intercomparisons. Datasets need to be easier to obtain and exploit for a wide constituency of users, with the differences and complementarities communicated in readily understood terms, and realistic and consistent uncertainty information provided. Steps were also recommended to curate and make available data that are presently inaccessible, develop new observing systems and build capacities to accelerate progress in the accuracy and usability of surface temperature datasets.

  6. The Surface Temperatures of the Earth: Steps towards Integrated Understanding of Variability and Change

    NASA Astrophysics Data System (ADS)

    Matthiesen, Stephan; Merchant, Chris; Rayner, Nick; Remedios, John; Høyer, Jacob L.; Jones, Phil; Olesen, Folke; Roquet, Hervé; Sobrino, José; Thorne, Peter

    2013-04-01

    Surface temperature is a key aspect of weather and climate, relevant to human health, agriculture and leisure, ecosystem services, infrastructure development and economic activity. In a community-based activity, the EarthTemp Network brought together 55 researchers from 5 continents to improve the interaction between scientific communities who focus on particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities. The Network idenitified key needs for progress towards meeting societal needs for surface temperature understanding and information, which will be reviewed and discussed in this contribution. A "whole-Earth" perspective is required with more integrated, collaborative approaches to observing and understanding Earth's various surface temperatures. It is necessary to build understanding of the relationships of different surface temperatures, where presently inadequate, and undertake large-scale systematic intercomparisons. Datasets need to be easier to obtain and exploit for a wide constituency of users, with the differences and complementarities communicated in readily understood terms, and realistic and consistent uncertainty information. Steps are also recommended to curate and make available data that are presently inaccessible, develop new observing systems and build capacities to accelerate progress in the accuracy and usability of surface temperature datasets.

  7. Integrated assessment of the spatial variability of ozone impacts from emissions of nitrogen oxides

    SciTech Connect

    Daniel Q. Tong; Nicholas Z. Muller; Denise L. Mauzerall; Robert O. Mendelsohn

    2006-03-01

    This paper examines the ozone (O{sub 3}) damages caused by nitrogen oxides (NOx) emissions in different locations around the Atlanta metropolitan area during a summer month. Ozone impacts are calculated using a new integrated assessment model that links pollution emissions to their chemical transformation, transport, population exposures, and effects on human health. It was found that increased NOx emissions in rural areas around Atlanta increase human exposure to ambient O{sub 3} twice as much as suburban emissions. However, increased NOx emissions in central city Atlanta actually reduce O{sub 3} exposures. For downtown emissions, the reduction in human exposures to O{sub 3} from titration by NO in the central city outweighs the effects from increased downwind O{sub 3}. The results indicate that the marginal damage from NOx emissions varies greatly across a metropolitan area. The results raise concerns if cap and trade regulations cause emissions to migrate toward higher marginal damage locations. 22 refs., 4 figs., 2 tabs.

  8. Integrating affective and cognitive correlates of heart rate variability: A structural equation modeling approach.

    PubMed

    Mann, Sarah L; Selby, Edward A; Bates, Marsha E; Contrada, Richard J

    2015-10-01

    High frequency heart rate variability (HRV) is a measure of neurocardiac communication thought to reflect predominantly parasympathetic cardiac regulation. Low HRV has been associated empirically with clinical and subclinical levels of anxiety and depression and, more recently, high levels of HRV have been associated with better performance on some measures of executive functioning (EF). These findings have offered support for theories proposing HRV as an index measure of a broad, self-regulatory capacity underlying aspects of emotion regulation and executive control. This study sought to test that proposition by using a structural equation modeling approach to examine the relationships of HRV to negative affect (NA) and EF in a large sample of U.S. adults ages 30s-80s. HRV was modeled as a predictor of an NA factor (self-reported trait anxiety and depression symptoms) and an EF factor (performance on three neuropsychological tests tapping facets of executive abilities). Alternative models also were tested to determine the utility of HRV for predicting NA and EF, with and without statistical control of demographic and health-related covariates. In the initial structural model, HRV showed a significant positive relationship to EF and a nonsignificant relationship to NA. In a covariate-adjusted model, HRV's associations with both constructs were nonsignificant. Age emerged as the only significant predictor of NA and EF in the final model, showing inverse relationships to both. Findings may reflect population and methodological differences from prior research; they also suggest refinements to the interpretations of earlier findings and theoretical claims regarding HRV.

  9. Understanding variability in posaconazole exposure using an integrated population pharmacokinetic analysis.

    PubMed

    Dolton, Michael J; Brüggemann, Roger J M; Burger, David M; McLachlan, Andrew J

    2014-11-01

    Posaconazole oral suspension is widely used for antifungal prophylaxis and treatment in immunocompromised patients, with highly variable pharmacokinetics reported in patients due to inconsistent oral absorption. This study aimed to characterize the pharmacokinetics of posaconazole in adults and investigate factors that influence posaconazole pharmacokinetics byusing a population pharmacokinetic approach. Nonlinear mixed-effects modeling was undertaken for two posaconazole studies in patients and healthy volunteers. The influences of demographic and clinical characteristics, such as mucositis, diarrhea, and drug-drug interactions, on posaconazole pharmacokinetics were investigated using a stepwise forward inclusion/backwards deletion procedure. A total of 905 posaconazole concentration measurements from 102 participants were analyzed. A one-compartment pharmacokinetic model with first-order oral absorption with lag time and first-order elimination best described posaconazole pharmacokinetics. Posaconazole relative bioavailability was 55% lower in patients who received posaconazole than in healthy volunteers. Coadministration of proton pump inhibitors (PPIs) or metoclopramide, as well as the occurrence of mucositis or diarrhea, reduced posaconazole relative bioavailability by 45%, 35%, 58%, and 45%, respectively, whereas concomitant ingestion of a nutritional supplement significantly increased bioavailability (129% relative increase). Coadministration of rifampin or phenytoin increased apparent posaconazole clearance by more than 600%, with a smaller increase observed with fosamprenavir (34%). Participant age, weight, or sex did not significantly affect posaconazole pharmacokinetics. Posaconazole absorption was reduced by a range of commonly coadministered medicines and clinical complications, such as mucositis and diarrhea. Avoidance of PPIs and metoclopramide and administration with food or a nutritional supplement are effective strategies to increase posaconazole

  10. A complete record of Holocene glacier variability at Austre Okstindbreen, northern Norway: an integrated approach

    NASA Astrophysics Data System (ADS)

    Bakke, Jostein; Dahl, Svein Olaf; Paasche, Øyvind; Riis Simonsen, Joachim; Kvisvik, Bjørn; Bakke, Kristina; Nesje, Atle

    2010-05-01

    Arctic glaciers are currently undergoing major changes, but accurate knowledge about how they varied during the entire Holocene is still scarce. Here we present a new complete glacier record from Austre Okstindbreen in Nordland, northern Norway. This reconstruction is based on a number of short and long cores retrieved from several downstream basins, which have been analyzed by a suite of methods including geochemical elements (XRF), rock magnetic properties, dry bulk density (DBD) and Loss-on-ignition (LOI). Lake sediment distribution was surveyed and mapped prior to coring by the use of ground penetrating radar (GPR). Independently lichen-dated marginal moraines and historical information about the glacier frontal positions from old photographs and maps have made it possible to link the moraine sequence to the 210Pb dated lake sediment chronology. This integrated approach reveals that Austre Okstindbreen is the first known glacier in Scandinavia to possibly have survived the "Holocene Thermal Optimum". It also brackets the four largest glacier advances to c 7400-7000, 1400-1200, 900-700 and 300-150 years before AD 2000 (b2k). In contrast to most reconstructed glaciers in Scandinavia, the largest glacier advance was not associated with the "Little Ice Age", but rather to an earlier period centred at 1300 b2k. Both the moraine chronology and the lacustrine records document this Neoglacial advance. Compared to other glacier reconstructions from the Northern Hemisphere, we identify near-synchronous glacier advances occurring roughly at 4000 b2k; 2700 b2k; 1300 b2k and during the "Little Ice Age". These correlative advances across the Northern Hemisphere suggest that these observed centennial-scale events are a shared feature regardless of the large geographical distances separating them. Some minor discrepancies between different geographical areas may be caused by lack of precise dating, but local climatic conditions may play a role as well.

  11. Mapping a near surface variable geologic regime using an integrated geophysical approach

    SciTech Connect

    Rogers, N.T.; Sandberg, S.K.; Miller, P.; Powell, G.

    1997-10-01

    An integrated geophysical approach involving seismic, electromagnetic, and electrical methods was employed to map fluvial, colluvial and bedrock geology, to delineate bedrock channels, and to determine fracture and joint orientations that may influence migration of petroleum hydrocarbons at the Glenrock Oil Seep. Both P (primary)-wave and S (shear)-wave seismic refraction techniques were used to map the bedrock surface topography, bedrock minima, stratigraphic boundaries, and possible structure. S-wave data were preferred because of better vertical resolution due to the combination of slower velocities and lower frequency wave train. Azimuthal resistivity/EP (induced polarization) and azimuthal electromagnetics were used to determine fracture orientations and groundwater flow directions. Terrain conductivity was used to map the fluvial sedimentary sequences (e.g., paleochannel and overbank deposits) in the North Platte River floodplain. Conductivity measurements were also used to estimate bedrock depth and to assist in the placement and recording parameters of the azimuthal soundings. The geophysical investigation indicated that groundwater flow pathways were controlled by the fluvial paleochannels and bedrock erosional features. Primary groundwater flow direction in the bedrock and colluvial sediments was determined from the azimuthal measurements and confirmed by drilling to be N20-40W along the measured strike of the bedrock and joint orientations. Joint/fracture orientations were measured at N20-40W and N10-30E from the azimuthal data and confirmed from measurements at a bedrock outcrop south of the site. The bedrock has an apparent N10E anisotropy in the seismic velocity profiles on the old refinery property that closely match that of measured joint/fracture orientations and may have a minor effect on groundwater flow.

  12. Integrating small mammal community variables into aircraft-wildlife collision management plans at Namibian airports.

    PubMed

    Hauptfleisch, Morgan L; Avenant, Nico L

    2015-11-01

    Understanding ecosystems within and around airports can help to determine the causes and possible mitigation measures for collisions between aircraft and wildlife. Small mammal communities are an important component of the semi-arid savanna ecosystems of Namibia, its productivity and its ecosystem integrity. They are also a major direct attractant for raptors at airports. The present study compared the abundance and diversity of small mammals between Namibia's 2 main airport properties (Hosea Kutako International Airport and Eros Airport), and among areas of land used for various purposes surrounding the airports. A total of 2150 small mammals (3 orders, 11 species) were captured over 4 trapping seasons. Small mammal abundance was significantly higher at the end of the growing season than during the non-growing season. The grass mowing regimen in current management plans at the airports resulted in a significant reduction of small mammal abundance at Hosea Kutako during the non-growing season only, thus indicating that annual mowing is effective but insufficient to reduce the overall abundance of mammal prey species for raptors. Small mammal numbers were significantly higher at Hosea Kutako Airport compared to the cattle and game farming land surrounding the airport, while no differences in small mammal densities or diversity were found for areas with different land uses at and surrounding Eros. The study suggests that the fence around Hosea Kutako provides a refuge for small mammals, resulting in higher densities. It also indicates that different surrounding land use practices result in altered ecosystem function and productivity, an important consideration when identifying wildlife attractants at airports. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  13. Advanced variable speed air source integrated heat pump (AS-IHP) development - CRADA final report

    SciTech Connect

    Baxter, Van D.; Rice, C. Keith; Munk, Jeffrey D.; Ally, Moonis Raza; Shen, Bo

    2015-09-30

    Between August 2011 and September 2015, Oak Ridge National Laboratory (ORNL) and Nordyne, LLC (now Nortek Global HVAC LLC, NGHVAC) engaged in a Cooperative Research and Development Agreement (CRADA) to develop an air-source integrated heat pump (AS-IHP) system for the US residential market. Two generations of laboratory prototype systems were designed, fabricated, and lab-tested during 2011-2013. Performance maps for the system were developed using the latest research version of the DOE/ORNL Heat Pump Design Model, or HPDM, (Rice 1991; Rice and Jackson 2005; Shen et al 2012) as calibrated against the lab test data. These maps were the input to the TRNSYS (SOLAR Energy Laboratory, et al, 2010) system to predict annual performance relative to a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (combination of 13 SEER air-source heat pump (ASHP) and resistance water heater with Energy Factor (EF) of 0.9). Predicted total annual energy savings, while providing space conditioning and water heating for a tight, well insulated 2600 ft2 (242 m2) house at 5 U.S. locations, ranged from 46 to 61%, averaging 52%, relative to the baseline system (lowest savings at the cold-climate Chicago location). Predicted energy use for water heating was reduced 62 to 76% relative to resistance WH. Based on these lab prototype test and analyses results a field test prototype was designed and fabricated by NGHVAC. The unit was installed in a 2400 ft2 (223 m2) research house in Knoxville, TN and field tested from May 2014 to April 2015. Based on the demonstrated field performance of the AS-IHP prototype and estimated performance of a baseline system operating under the same loads and weather conditions, it was estimated that the prototype would achieve ~40% energy savings relative to the minimum efficiency suite. The estimated WH savings were >60% and SC mode savings were >50%. But estimated SH savings were only about 20%. It is believed that had the test

  14. Inversion of magnetotelluric data using integral equation approach with variable sensitivity domain: Application to EarthScope MT data

    NASA Astrophysics Data System (ADS)

    Čuma, Martin; Gribenko, Alexander; Zhdanov, Michael S.

    2017-09-01

    We have developed a multi-level parallel magnetotelluric (MT) integral equation based inversion program which uses variable sensitivity domain. The limited sensitivity of the data, which decreases with increasing frequency, is exploited by a receiver sensitivity domain, which also varies with frequency. We assess the effect of inverting principal impedances, full impedance tensor, and full tensor jointly with magnetovariational data (tipper). We first apply this method to several models and then invert the EarthScope MT data. We recover well the prominent features in the area including resistive structure associated with the Juan de Fuca slab subducting beneath the northwestern United States, the conductive zone of partially melted material above the subducting slab at the Cascade volcanic arc, conductive features in the Great Basin and in the area of Yellowstone associated with the hot spot, and resistive areas to the east corresponding to the older and more stable cratons.

  15. Variability of the seasonally integrated normalized difference vegetation index across the north slope of Alaska in the 1990s

    USGS Publications Warehouse

    Stow, D.; Daeschner, S.; Hope, A.; Douglas, D.; Petersen, A.; Myneni, R.; Zhou, L.; Oechel, W.

    2003-01-01

    The interannual variability and trend of above-ground photosynthetic activity of Arctic tundra vegetation in the 1990s is examined for the north slope region of Alaska, based on the seasonally integrated normalized difference vegetation index (SINDVI) derived from local area coverage (LAC) National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) data. Smaller SINDVI values occurred during the three years (1992-1994) following the volcanic eruption of Mt Pinatubo. Even after implementing corrections for this stratospheric aerosol effect and adjusting for changes in radiometric calibration coefficients, an apparent increasing trend of SINDVI in the 1990s is evident for the entire north slope. The most pronounced increase was observed for the foothills physiographical province.

  16. Open spin chains with generic integrable boundaries: Baxter equation and Bethe ansatz completeness from separation of variables

    NASA Astrophysics Data System (ADS)

    Kitanine, N.; Maillet, J. M.; Niccoli, G.

    2014-05-01

    We solve the longstanding problem of defining a functional characterization of the spectrum of the transfer matrix associated with the most general spin-1/2 representations of the six-vertex reflection algebra for general inhomogeneous chains. The corresponding homogeneous limit reproduces the spectrum of the Hamiltonian of the spin-1/2 open XXZ and XXX quantum chains with the most general integrable boundaries. The spectrum is characterized by a second order finite difference functional equation of Baxter type with an inhomogeneous term which vanishes only for some special but yet interesting non-diagonal boundary conditions. This functional equation is shown to be equivalent to the known separation of variables (SOV) representation, hence proving that it defines a complete characterization of the transfer matrix spectrum. The polynomial form of the Q-function allows us to show that a finite system of generalized Bethe equations can also be used to describe the complete transfer matrix spectrum.

  17. Inter-annual variability of air pollutants over East Asia: an integrated analysis using satellite, lidar and numerical model.

    NASA Astrophysics Data System (ADS)

    Yumimoto, K.; Uno, I.; Kuribayashi, M.; Miyazaki, K.; Nishizawa, T.

    2014-12-01

    Air quality in East Asia has a drastic temporal and spatial variability. The rapid economic growth in the last three decades enhanced the increase of anthropogenic emission of air pollutions, and caused deterioration of the air quality in both source and downwind regions. The unprecedented heavy PM­2.5 pollution over the central China in January 2013 records the maximum PM2.5 concentration of 996 μg/m3 and raised critical environmental issues (e.g., mortality, human health, social activity and trans-boundary transport, etc.). Recently, efforts to reduce anthropogenic emissions (e.g., emission regulations and improvements of emission factors and removal efficiencies) decelerate their growth rates. In fact, Asian SO2 emission is estimated to be reducing from 2007 [Kurokawa et al., 2013]. However, growth rates other pollutant emissions (e.g., NOx and PM10) still remain in high. To understand the life cycle of pollutants (emission, transport, reaction and deposition) and their temporal and spatial variation, an integrated analysis using observation and numerical model (chemical transport model; CTM) is useful. In this study, we installed a comprehensive observation operator system, which converts model results into observed variables, into the GEOS-Chem CTM. A long-term (2005-2013) full-chemistry simulation over East Asia was performed, and simulation results are translated to tropospheric NO2 and SO2 columns and vertical profiles of aerosol extinction coefficient equivalent to satellite measurements and in-situ lidar network observations. Combining CTM and observations, and integrating analyses of aerosols over the downwind region and their precursors over the source region will provide important insights into temporal and spatial variation of air pollutants over East Asia.

  18. Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera

    NASA Astrophysics Data System (ADS)

    Wan, Yuhang; Carlson, John A.; Kesler, Benjamin A.; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A.; Lim, Sung Jun; Smith, Andrew M.; Dallesasse, John M.; Cunningham, Brian T.

    2016-07-01

    A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid’s absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics.

  19. Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera

    PubMed Central

    Wan, Yuhang; Carlson, John A.; Kesler, Benjamin A.; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A.; Lim, Sung Jun; Smith, Andrew M.; Dallesasse, John M.; Cunningham, Brian T.

    2016-01-01

    A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid’s absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics. PMID:27389070

  20. Effect of decisive formulation variables on bioencapsulation efficiency and integrity of yeast biocapsules for oral itraconazole delivery.

    PubMed

    Sangwai, Mayur B; Vavia, Pradeep Ratilal

    2011-01-01

    Reproducible delivery of drugs through bioencapsulation in cellular carriers is severely limited by biovariability in cellular carriers and effects of decisive formulation variables. Surmounting the constraints in reproducible results, our work explores optimization methodology for precise and reproducible cellular bioencapsulation technology for poorly water soluble drug. Active-dried baker's yeast cells were selected as cellular carriers for poorly soluble antimycotic agent itraconazole (ITZ). Pre-treatment of yeast cells with various techniques exhibited substantial augmentation in bioencapsulation efficiency (%BE). Sequentially optimized values of formulation variables like bioencapsulation temperature (40-50°C), stirring rate (350 rpm) and time (5 h) exhibited highest %BE with desired reproducibility. In comparison with marketed product, bioencapsulated itraconazole demonstrated marked increase in solubility with more than 70% release in 10 min. Compression pressure equivalent to tablet hardness of 2.0-3.5 kg/cm(2) was optimum to maintain integrity of biocapsules. Resulting biocapsules exhibited safe residual solvent content, inertness for fermentation ability and excellent stability at accelerated conditions.

  1. An index of ecological integrity for the Mississippi alluvial plain ecoregion: index development and relations to selected landscape variables

    USGS Publications Warehouse

    Justus, B.G.

    2003-01-01

    Macroinvertebrate community, fish community, water-quality, and habitat data collected from 36 sites in the Mississippi Alluvial Plain Ecoregion during 1996-98 by the U.S. Geological Survey were considered for a multimetric test of ecological integrity. Test metrics were correlated to site scores of a Detrended Correspondence Analysis of the fish community (the biological community that was the most statistically significant for indicating ecological conditions in the ecoregion) and six metrics--four fish metrics, one chemical metric (total ammonia plus organic nitrogen) and one physical metric (turbidity)--having the highest correlations were selected for the index. Index results indicate that sites in the northern half of the study unit (in Arkansas and Missouri) were less degraded than sites in the southern half of the study unit (in Louisiana and Mississippi). Of 148 landscape variables evaluated, the percentage of Holocene deposits and cotton insecticide rates had the highest correlations to index of ecological integrity results. sites having the highest (best) index scores had the lowest percentages of Holocene deposits and the lowest cotton insecticide use rates, indicating that factors relating to the amount of Holocene deposits and cotton insecticide use rates partially explain differences in ecological conditions throughout the Mississippi Alluvial Plain Ecoregion.

  2. Measuring the effects of excluded variables in the LLNL energy-policy model: report on a model integration

    SciTech Connect

    Cooper, R.; Rambo, J.; Wood, D.O.

    1981-10-01

    The LLNL Energy Policy Model (EPM) is a large network model (80,000 nodes) of the US energy system. The model accounts for the production, transport, conversion, and distribution of primary energy for end-use applications. Given end-use demands and associated model data, a model solution consists of the equilibrium prices and quantities of primary, intermediate, and final energy forms, as well as investment requirements and characteristics of production, conversion, and end-use technologies. A characteristic of the EPM (as well as similar energy system process models) is that not all goods and services used in production and consumed by households are considered. The assmption is made that energy forms and energy-related capital are separable from other goods and services, and that the substitution possibilities between these two sets of variables is zero. Results are presented of an effort to integrate the EPM with a simple aggregate model of US manufacturing input factor demands, including capital and energy, which relaxes the zero-elasticity assumption. After describing the approach to integration, simulation results that demonstrate the effects on EPM results of considering the originally excluded inputs are presented. The energy costs and consumption implications of several national energy policy scenarios are also analyzed.

  3. Microcontroller Based Proportional Derivative Plus Conditional Integral Controller for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission Ratio Control

    NASA Astrophysics Data System (ADS)

    Budianto, A.; Tawi, K. B.; Hussein, M.; Supriyo, B.; Ariyono, S.; Che Kob, M. S.; Ezlamy Zulkifli, Mohd; K, Khairuldean A.; Daraoh, Aishah

    2012-09-01

    Electro-Mechanical Dual Acting Pulley (EMDAP) Continuously Variable Transmission (CVT) is a transmission utilized by electro-mechanical actuated system. It has a potential to reduce energy consumption because it only needs power during changing CVT ratio and no power is needed to maintain CVT ratio due to self lock mechanism design. This paper proposed simple proportional derivative plus conditional integral (PDCI) controller to control EMDAP CVT ratio which can be simply implemented on a microcontroller. This proposed controller used Astrom-Hagglund method and Ziegler-Nichols formula to tune PDCI gain. The Proportional Derivative controller is directly activated from the start but Integral controller is only activated when the error value reaches error value setting point. Simulation using Matlab/Simulink software was conducted to evaluate PDCI system performance. The simulation results showed PDCI controller has ability to perform maximum overshoot 0.1%, 0.001 steady state error and 0.5s settling time. For clamping condition, settling time is about 11.46s during changing ratio from 2.0 to 0.7, while for release condition, settling time is about 8.33s during changing ratio from 0.7 to 2.0.

  4. Modified internal state variable models of plasticity using nonlocal integrals in damage and gradients in dislocation density

    NASA Astrophysics Data System (ADS)

    Ahad, Fazle Rabbi

    To enhance material performance at different length scales, this study strives to develop a reliable analytical and computational tool with the help of internal state variables spanning micro and macro-level behaviors. First, the practical relevance of a nonlocal damage integral added to an internal state variable (BCJ) model is studied to alleviate numerical instabilities associated within the post-bifurcation regime. The characteristic length scale in the nonlocal damage, which is mathematical in nature, can be calibrated using a series of notch tensile tests. Then the same length scale from the notch tests is used in solving the problem of a high-velocity (between 89 and 107 m/s) rigid projectile colliding against a 6061-T6 aluminum-disk. The investigation indicates that incorporating a characteristic length scale to the constitutive model eliminates the pathological mesh-dependency associated with material instabilities. In addition, the numerical calculations agree well with experimental data. Next, an effort is made rather to introduce a physically motivated length scale than to apply a mathematical-one in the deformation analysis. Along this line, a dislocation based plasticity model is developed where an intrinsic length scale is introduced in the forms of spatial gradients of mobile and immobile dislocation densities. The spatial gradients are naturally invoked from balance laws within a consistent kinematic and thermodynamic framework. An analytical solution of the model variables is derived at homogenous steady state using the linear stability and bifurcation analysis. The model qualitatively captures the formation of dislocation cell-structures through material instabilities at the microscopic level. Finally, the model satisfactorily predicts macroscopic mechanical behaviors - e.g., multi-strain rate uniaxial compression, simple shear, and stress relaxation - and validates experimental results.

  5. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability

    PubMed Central

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L.

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. PMID:25324790

  6. Global trends and variability in integrated water vapour from ground-based GPS data and atmospheric models

    NASA Astrophysics Data System (ADS)

    Bock, Olivier; Parracho, Ana; Bastin, Sophie; Hourdin, Frededic; Mellul, Lidia

    2016-04-01

    A high-quality, consistent, global, long-term dataset of integrated water vapour (IWV) was produced from Global Positioning System (GPS) measurements at more than 400 sites over the globe among which 120 sites have more than 15 years of data. The GPS delay data were converted to IWV using surface pressure and weighted mean temperature estimates from ERA-Interim reanalysis. A two-step screening method was developed to detect and remove outliers in the IWV data. It is based on: 1) GPS data processing information and delay formal errors, and 2) intercomparison with ERA-Interim reanalysis data. The GPS IWV data are also homogenized to correct for offsets due to instrumental changes and other unknown factors. The differential homogenization method uses ERA-Interim IWV as a reference. The resulting GPS data are used to document the mean distribution, the global trends and the variability of IWV over the period 1995-2010, and are analysed in coherence with precipitation and surface temperature data (from observations and ERA-Interim reanalysis). These data are also used to assess global climate model simulations extracted from the IPCC AR5 archive. Large coherent spatial patterns of moistening and drying are evidenced but significant discrepancies are also seen between GPS measurements, reanalysis and climate models in various regions. In terms of variability, the monthly mean anomalies are intercompared. The temporal correlation between GPS and the climate model simulations is overall quite small but the spatial variation of the magnitude of the anomalies is globally well simulated. GPS IWV data prove to be useful to validate global climate model simulations and highlight deficiencies in their representation of the water cycle.

  7. Enhancing the Design Process for Complex Space Systems through Early Integration of Risk and Variable-Fidelity Modeling

    NASA Technical Reports Server (NTRS)

    Mavris, Dimitri; Osburg, Jan

    2005-01-01

    An important enabler of the new national Vision for Space Exploration is the ability to rapidly and efficiently develop optimized concepts for the manifold future space missions that this effort calls for. The design of such complex systems requires a tight integration of all the engineering disciplines involved, in an environment that fosters interaction and collaboration. The research performed under this grant explored areas where the space systems design process can be enhanced: by integrating risk models into the early stages of the design process, and by including rapid-turnaround variable-fidelity tools for key disciplines. Enabling early assessment of mission risk will allow designers to perform trades between risk and design performance during the initial design space exploration. Entry into planetary atmospheres will require an increased emphasis of the critical disciplines of aero- and thermodynamics. This necessitates the pulling forward of EDL disciplinary expertise into the early stage of the design process. Radiation can have a large potential impact on overall mission designs, in particular for the planned nuclear-powered robotic missions under Project Prometheus and for long-duration manned missions to the Moon, Mars and beyond under Project Constellation. This requires that radiation and associated risk and hazards be assessed and mitigated at the earliest stages of the design process. Hence, RPS is another discipline needed to enhance the engineering competencies of conceptual design teams. Researchers collaborated closely with NASA experts in those disciplines, and in overall space systems design, at Langley Research Center and at the Jet Propulsion Laboratory. This report documents the results of this initial effort.

  8. Variable Step Integration Coupled with the Method of Characteristics Solution for Water-Hammer Analysis, A Case Study

    NASA Technical Reports Server (NTRS)

    Turpin, Jason B.

    2004-01-01

    One-dimensional water-hammer modeling involves the solution of two coupled non-linear hyperbolic partial differential equations (PDEs). These equations result from applying the principles of conservation of mass and momentum to flow through a pipe, and usually the assumption that the speed at which pressure waves propagate through the pipe is constant. In order to solve these equations for the interested quantities (i.e. pressures and flow rates), they must first be converted to a system of ordinary differential equations (ODEs) by either approximating the spatial derivative terms with numerical techniques or using the Method of Characteristics (MOC). The MOC approach is ideal in that no numerical approximation errors are introduced in converting the original system of PDEs into an equivalent system of ODEs. Unfortunately this resulting system of ODEs is bound by a time step constraint so that when integrating the equations the solution can only be obtained at fixed time intervals. If the fluid system to be modeled also contains dynamic components (i.e. components that are best modeled by a system of ODEs), it may be necessary to take extremely small time steps during certain points of the model simulation in order to achieve stability and/or accuracy in the solution. Coupled together, the fixed time step constraint invoked by the MOC, and the occasional need for extremely small time steps in order to obtain stability and/or accuracy, can greatly increase simulation run times. As one solution to this problem, a method for combining variable step integration (VSI) algorithms with the MOC was developed for modeling water-hammer in systems with highly dynamic components. A case study is presented in which reverse flow through a dual-flapper check valve introduces a water-hammer event. The predicted pressure responses upstream of the check-valve are compared with test data.

  9. Robust integration schemes for generalized viscoplasticity with internal-state variables. Part 1: Theoretical developments and applications

    NASA Technical Reports Server (NTRS)

    Saleeb, Atef F.; Li, Wei

    1995-01-01

    This two-part report is concerned with the development of a general framework for the implicit time-stepping integrators for the flow and evolution equations in generalized viscoplastic models. The primary goal is to present a complete theoretical formulation, and to address in detail the algorithmic and numerical analysis aspects involved in its finite element implementation, as well as to critically assess the numerical performance of the developed schemes in a comprehensive set of test cases. On the theoretical side, the general framework is developed on the basis of the unconditionally-stable, backward-Euler difference scheme as a starting point. Its mathematical structure is of sufficient generality to allow a unified treatment of different classes of viscoplastic models with internal variables. In particular, two specific models of this type, which are representative of the present start-of-art in metal viscoplasticity, are considered in applications reported here; i.e., fully associative (GVIPS) and non-associative (NAV) models. The matrix forms developed for both these models are directly applicable for both initially isotropic and anisotropic materials, in general (three-dimensional) situations as well as subspace applications (i.e., plane stress/strain, axisymmetric, generalized plane stress in shells). On the computational side, issues related to efficiency and robustness are emphasized in developing the (local) interative algorithm. In particular, closed-form expressions for residual vectors and (consistent) material tangent stiffness arrays are given explicitly for both GVIPS and NAV models, with their maximum sizes 'optimized' to depend only on the number of independent stress components (but independent of the number of viscoplastic internal state parameters). Significant robustness of the local iterative solution is provided by complementing the basic Newton-Raphson scheme with a line-search strategy for convergence. In the present first part of the

  10. Robust integration schemes for generalized viscoplasticity with internal-state variables. Part 1: Theoretical developments and applications

    NASA Astrophysics Data System (ADS)

    Saleeb, Atef F.; Li, Wei

    1995-05-01

    This two-part report is concerned with the development of a general framework for the implicit time-stepping integrators for the flow and evolution equations in generalized viscoplastic models. The primary goal is to present a complete theoretical formulation, and to address in detail the algorithmic and numerical analysis aspects involved in its finite element implementation, as well as to critically assess the numerical performance of the developed schemes in a comprehensive set of test cases. On the theoretical side, the general framework is developed on the basis of the unconditionally-stable, backward-Euler difference scheme as a starting point. Its mathematical structure is of sufficient generality to allow a unified treatment of different classes of viscoplastic models with internal variables. In particular, two specific models of this type, which are representative of the present start-of-art in metal viscoplasticity, are considered in applications reported here; i.e., fully associative (GVIPS) and non-associative (NAV) models. The matrix forms developed for both these models are directly applicable for both initially isotropic and anisotropic materials, in general (three-dimensional) situations as well as subspace applications (i.e., plane stress/strain, axisymmetric, generalized plane stress in shells). On the computational side, issues related to efficiency and robustness are emphasized in developing the (local) interative algorithm. In particular, closed-form expressions for residual vectors and (consistent) material tangent stiffness arrays are given explicitly for both GVIPS and NAV models, with their maximum sizes 'optimized' to depend only on the number of independent stress components (but independent of the number of viscoplastic internal state parameters). Significant robustness of the local iterative solution is provided by complementing the basic Newton-Raphson scheme with a line-search strategy for convergence. In the present first part of the

  11. Hydrological Responses of Andean Lakes and Tropical Floodplains to Climate Variability and Human Intervention: an Integrative Modelling Framework

    NASA Astrophysics Data System (ADS)

    Hoyos, I. C.; González Morales, C.; Serna López, J. P.; Duque, C. L.; Canon Barriga, J. E.; Dominguez, F.

    2013-12-01

    Andean water bodies in tropical regions are significantly influenced by fluctuations associated with climatic and anthropogenic drivers, which implies long term changes in mountain snow peaks, land covers and ecosystems, among others. Our work aims at providing an integrative framework to realistically assess the possible future of natural water bodies with different degrees of human intervention. We are studying in particular the evolution of three water bodies in Colombia: two Andean lakes and a floodplain wetland. These natural reservoirs represent the accumulated effect of hydrological processes in their respective basins, which exhibit different patterns of climate variability and distinct human intervention and environmental histories. Modelling the hydrological responses of these local water bodies to climate variability and human intervention require an understanding of the strong linkage between geophysical and social factors. From the geophysical perspective, the challenge is how to downscale global climate projections in the local context: complex orography and relative lack of data. To overcome this challenge we combine the correlational and physically based analysis of several sources of spatially distributed biophysical and meteorological information to accurately determine aspects such as moisture sources and sinks and past, present and future local precipitation and temperature regimes. From the social perspective, the challenge is how to adequately represent and incorporate into the models the likely response of social agents whose water-related interests are diverse and usually conflictive. To deal with the complexity of these systems we develop interaction matrices, which are useful tools to holistically discuss and represent each environment as a complex system. Our goal is to assess partially the uncertainties of the hydrological balances in these intervened water bodies we establish climate/social scenarios, using hybrid models that combine

  12. Integration of MODIS-derived metrics to assess interannual variability in snowpack, lake ice, and NDVI in southwest Alaska

    USGS Publications Warehouse

    Reed, Bradley C.; Budde, Michael E.; Spencer, Page; Miller, Amy E.

    2009-01-01

    Impacts of global climate change are expected to result in greater variation in the seasonality of snowpack, lake ice, and vegetation dynamics in southwest Alaska. All have wide-reaching physical and biological ecosystem effects in the region. We used Moderate Resolution Imaging Spectroradiometer (MODIS) calibrated radiance, snow cover extent, and vegetation index products for interpreting interannual variation in the duration and extent of snowpack, lake ice, and vegetation dynamics for southwest Alaska. The approach integrates multiple seasonal metrics across large ecological regions. Throughout the observation period (2001-2007), snow cover duration was stable within ecoregions, with variable start and end dates. The start of the lake ice season lagged the snow season by 2 to 3??months. Within a given lake, freeze-up dates varied in timing and duration, while break-up dates were more consistent. Vegetation phenology varied less than snow and ice metrics, with start-of-season dates comparatively consistent across years. The start of growing season and snow melt were related to one another as they are both temperature dependent. Higher than average temperatures during the El Ni??o winter of 2002-2003 were expressed in anomalous ice and snow season patterns. We are developing a consistent, MODIS-based dataset that will be used to monitor temporal trends of each of these seasonal metrics and to map areas of change for the study area.

  13. White matter integrity and reaction time intraindividual variability in healthy aging and early-stage Alzheimer disease.

    PubMed

    Jackson, Jonathan D; Balota, David A; Duchek, Janet M; Head, Denise

    2012-02-01

    Aging and early-stage Alzheimer disease (AD) have been shown to be associated with increased RT intraindividual variability (IIV, as reflected by the coefficient of variation) and an exaggeration of the slow tail of the reaction time (RT) distribution in attentional control tasks, based on ex-Gaussian analyses. The current study examined associations between white matter volume, IIV, and ex-Gaussian RT distribution parameters in cognitively normal aging and early-stage AD. Three RT attention tasks (Stroop, Simon, and a consonant-vowel odd-even switching task) in conjunction with MRI-based measures of cerebral and regional white matter volume were obtained in 133 cognitively normal and 33 early-stage AD individuals. Larger volumes were associated with less IIV and less slowing in the tail of the RT distribution, and larger cerebral and inferior parietal white matter volumes were associated with faster modal reaction time. Collectively, these results support a role of white matter integrity in IIV and distributional skewing, and are consistent with the hypothesis that IIV and RT distributional skewing are sensitive to breakdowns in executive control processes in normal and pathological aging.

  14. Hydrologic variability and the application of Index of Biotic Integrity metrics to wetlands: a Great Lakes evaluation

    USGS Publications Warehouse

    Wilcox, Douglas A.; Meeker, James E.; Hudson, Patrick L.; Armitage, Brian J.; Black, M. Glen; Uzarski, Donald G.

    2002-01-01

    Interest by land-management and regulatory agencies in using biological indicators to detect wetland degradation, coupled with ongoing use of this approach to assess water quality in streams, led to the desire to develop and evaluate an Index of Biotic Integrity (IBI) for wetlands that could be used to categorize the level of degradation. We undertook this challenge with data from coastal wetlands of the Great Lakes, which have been degraded by a variety of human disturbances. We studied six barrier beach wetlands in western Lake Superior, six drowned-river-mouth wetlands along the eastern shore of Lake Michigan, and six open shoreline wetlands in Saginaw Bay of Lake Huron. Plant, fish, and invertebrate communities were sampled in each wetland. The resulting data were assessed in various forms against gradients of human disturbance to identify potential metrics that could be used in IBI development. Our results suggested that the metrics proposed as potential components of an IBI for barrier beach wetlands of Lake Superior held promise. The metrics for Lake Michigan drowned-river-mouth wetlands were inconsistent in identifying gradients of disturbance; those for Lake Huron open embayment wetlands were yet more inconsistent. Despite the potential displayed by the Lake Superior results within the year sampled, we concluded that an IBI for use in Great Lakes wetlands would not be valid unless separate scoring ranges were derived for each of several sequences of water-level histories. Variability in lake levels from year to year can produce variability in data and affect the reproducibility of data collected, primarily due to extreme changes in plant communities and the faunal habitat they provide. Substantially different results could be obtained in the same wetland in different years as a result of the response to lake-level change, with no change in the level of human disturbance. Additional problems included limited numbers of comparable sites, potential lack of

  15. Neurocranium versus Face: A Morphometric Approach with Classical Anthropometric Variables for Characterizing Patterns of Cranial Integration in Extant Hominoids and Extinct Hominins.

    PubMed

    Pérez-Claros, Juan Antonio; Jiménez-Arenas, Juan Manuel; Palmqvist, Paul

    2015-01-01

    The relative importance of the two main cranial complexes, the neurocranium and the splanchnocranium, has been examined in the five species of extant hominoids and in a huge sample of extinct hominins using six standard craniometric variables that measure the length, width and height of each cranial module. Factor analysis and two-block partial least squares were used for establishing the major patterns of developmental and evolutionary integration between both cranial modules. The results obtained show that all extant hominoids (including the anatomically modern humans) share a conserved pattern of developmental integration, a result that agrees with previous studies. The pattern of evolutionary integration between both cranial modules in australopiths runs in parallel to developmental integration. In contrast, the pattern of evolutionary and developmental integration of the species of the genus Homo is the opposite, which is probably the consequence of distinctive selective regimes for both hominin groups.

  16. Neurocranium versus Face: A Morphometric Approach with Classical Anthropometric Variables for Characterizing Patterns of Cranial Integration in Extant Hominoids and Extinct Hominins

    PubMed Central

    Pérez-Claros, Juan Antonio; Jiménez-Arenas, Juan Manuel; Palmqvist, Paul

    2015-01-01

    The relative importance of the two main cranial complexes, the neurocranium and the splanchnocranium, has been examined in the five species of extant hominoids and in a huge sample of extinct hominins using six standard craniometric variables that measure the length, width and height of each cranial module. Factor analysis and two-block partial least squares were used for establishing the major patterns of developmental and evolutionary integration between both cranial modules. The results obtained show that all extant hominoids (including the anatomically modern humans) share a conserved pattern of developmental integration, a result that agrees with previous studies. The pattern of evolutionary integration between both cranial modules in australopiths runs in parallel to developmental integration. In contrast, the pattern of evolutionary and developmental integration of the species of the genus Homo is the opposite, which is probably the consequence of distinctive selective regimes for both hominin groups. PMID:26177535

  17. Stability of FDG-PET Radiomics features: An integrated analysis of test-retest and inter-observer variability

    PubMed Central

    LEIJENAR, RALPH T. H.; CARVALHO, SARA; ZQUEZ, EMMANUEL RIOS VELA; VAN ELMPT, WOUTER J. C.; PARMAR, CHINTAN; HOEKSTRA, OTTO S.; HOEKSTRA, CORNELINE J.; BOELARD, RONALD; DEKKER, ANDRÉ L. A. J.; GILLIES, ROBERT J.; AERTS, HUGO J. W. L.; LAMBIN, PHILIPPE

    2015-01-01

    Purpose Besides basic measurements as maximum standardized uptake value (SUV)max or SUVmean derived from 18F-FDG positron emission tomography (PET) scans, more advanced quantitative imaging features (i.e. “Radiomics” features) are increasingly investigated for treatment monitoring, outcome prediction, or as potential biomarkers. With these prospected applications of Radiomics features, it is a requisite that they provide robust and reliable measurements. The aim of our study was therefore to perform an integrated stability analysis of a large number of PET-derived features in non-small cell lung carcinoma (NSCLC), based on both a test-retest and an inter-observer setup. Methods Eleven NSCLC patients were included in the test-retest cohort. Patients underwent repeated PET imaging within a one day interval, before any treatment was delivered. Lesions were delineated by applying a threshold of 50% of the maximum uptake value within the tumor. Twenty-three NSCLC patients were included in the inter-observer cohort. Patients underwent a diagnostic whole body PET-computed tomography (CT). Lesions were manually delineated based on fused PET-CT, using a standardized clinical delineation protocol. Delineation was performed independently by five observers, blinded to each other. Fifteen first order statistics, 39 descriptors of intensity volume histograms, eight geometric features and 44 textural features were extracted. For every feature, test-retest and inter-observer stability was assessed with the intra-class correlation coefficient (ICC) and the coefficient of variability, normalized to mean and range. Similarity between test-retest and inter-observer stability rankings of features was assessed with Spearman’s rank correlation coefficient. Results Results showed that the majority of assessed features had both a high test-retest (71%) and inter-observer (91%) stability in terms of their ICC. Overall, features more stable in repeated PET imaging were also found to be

  18. Linking above- and belowground traits to soil and climate variables: an integrated database on China's grassland species.

    PubMed

    Geng, Yan; Ma, Wenhong; Wang, Liang; Baumann, Frank; Kühn, Peter; Scholten, Thomas; He, Jin-Sheng

    2017-02-27

    Knowledge of plant functional traits and trait-environment interactions is important for characterizing species strategies and understanding ecological processes. However, comprehensive field data on both above- and belowground traits, together with their environmental variables are scarce. Biome-scale studies are particularly lacking. Here we present two large-scale datasets that include functional traits of leaves and fine roots and their corresponding soil and climatic variables in China's grasslands. Leaf, fine root and soil samples were collected in three biogeographic regions: temperate grassland on the Inner Mongolia Plateau, alpine grassland on the Tibetan Plateau, and mountain grassland in the Xinjiang mountain areas. Field data were collected over two periods. The first dataset collected between 2003 and 2004 includes thirteen foliar traits (leaf mass per area, LMA; photosynthetic nitrogen use efficiency, PNUE; water use efficiency, WUE; stomatal conductance for water vapor, Gs; transpiration rate, TR; mass and area based photosynthetic capacity, Amass and Aarea; mass and area based carbon concentrations, Cmass and Carea; nitrogen concentrations, Nmass and Narea; and phosphorus concentrations, Pmass and Parea) for 170 species at 173 sites. The second dataset collected between 2006 and 2007 includes six sets of analogous traits for both leaves and fine roots (C, N and P concentrations; leaf thickness/root diameter; specific leaf area, SLA/specific root length, SRL; and tissue density) for 139 species at 82 sites, along with soil attributes (soil total and organic carbon, STC and SOC; total and available N, STN and SAN; total and available P, STP and SAP; pH, bulk density and moisture). Moreover, associated information was also gathered, including geographical location (latitude, longitude and altitude), climate (mean annual temperature, MAT; mean annual precipitation, MAP; growing season temperature, GST; growing season precipitation, GSP; potential

  19. [Integrity].

    PubMed

    Gómez Rodríguez, Rafael Ángel

    2014-01-01

    To say that someone possesses integrity is to claim that that person is almost predictable about responses to specific situations, that he or she can prudentially judge and to act correctly. There is a closed interrelationship between integrity and autonomy, and the autonomy rests on the deeper moral claim of all humans to integrity of the person. Integrity has two senses of significance for medical ethic: one sense refers to the integrity of the person in the bodily, psychosocial and intellectual elements; and in the second sense, the integrity is the virtue. Another facet of integrity of the person is la integrity of values we cherish and espouse. The physician must be a person of integrity if the integrity of the patient is to be safeguarded. The autonomy has reduced the violations in the past, but the character and virtues of the physician are the ultimate safeguard of autonomy of patient. A field very important in medicine is the scientific research. It is the character of the investigator that determines the moral quality of research. The problem arises when legitimate self-interests are replaced by selfish, particularly when human subjects are involved. The final safeguard of moral quality of research is the character and conscience of the investigator. Teaching must be relevant in the scientific field, but the most effective way to teach virtue ethics is through the example of the a respected scientist.

  20. Integral field spectroscopy of M1-67. A Wolf-Rayet nebula with luminous blue variable nebula appearance

    NASA Astrophysics Data System (ADS)

    Fernández-Martín, A.; Vílchez, J. M.; Pérez-Montero, E.; Candian, A.; Sánchez, S. F.; Martín-Gordón, D.; Riera, A.

    2013-06-01

    Aims: This work aims to disentangle the morphological, kinematic, and chemical components of the nebula M1-67 to shed light on its process of formation around the central Wolf-Rayet (WR) star WR124. Methods: We have carried out integral field spectroscopy observations over two regions of M1-67, covering most of the nebula in the optical range. Maps of electron density, line ratios, and radial velocity were created to perform a detailed analysis of the two-dimensional structure. We studied the physical and chemical properties by means of integrated spectra selected over the whole nebula. Photoionization models were performed to confirm the empirical chemical results theoretically. In addition, we obtained and analysed infrared spectroscopic data and the MIPS 24 μm image of M1-67 from Spitzer. Results: We find that the ionized gas of M1-67 is condensed in knots aligned in a preferred axis along the NE-SW direction, like a bipolar structure. Both electron density and radial velocity decrease in this direction when moving away from the central star. From the derived electron temperature, Te ~ 8200 K, we have estimated chemical abundances, obtaining that nitrogen appears strongly enriched and oxygen depleted. From the last two results, we infer that this bipolarity is the consequence of an ejection of an evolved stage of WR124 with material processed in the CNO cycle. Furthermore, we find two regions placed outside of the bipolar structure with different spectral and chemical properties. The infrared study has revealed that the bipolar axis is composed of ionized gas with a low ionization degree that is well mixed with warm dust and of a spherical bubble surrounding the ejection at 24 μm. Taking the evolution of a 60 M⊙ star and the temporal scale of the bipolar ejection into account, we propose that the observed gas was ejected during an eruption in the luminous blue variable stage. The star has entered the WR phase recently without apparent signs of interaction

  1. Integrating Environmental and Socio-Economic Indicators of a Linked Catchment-Coastal System Using Variable Environmental Intensity

    NASA Astrophysics Data System (ADS)

    Dymond, John R.; Davie, Tim J. A.; Fenemor, Andrew D.; Ekanayake, Jagath C.; Knight, Ben R.; Cole, Anthony O.; de Oca Munguia, Oscar Montes; Allen, Will J.; Young, Roger G.; Basher, Les R.; Dresser, Marc; Batstone, Chris J.

    2010-09-01

    Can we develop land use policy that balances the conflicting views of stakeholders in a catchment while moving toward long term sustainability? Adaptive management provides a strategy for this whereby measures of catchment performance are compared against performance goals in order to progressively improve policy. However, the feedback loop of adaptive management is often slow and irreversible impacts may result before policy has been adapted. In contrast, integrated modelling of future land use policy provides rapid feedback and potentially improves the chance of avoiding unwanted collapse events. Replacing measures of catchment performance with modelled catchment performance has usually required the dynamic linking of many models, both biophysical and socio-economic—and this requires much effort in software development. As an alternative, we propose the use of variable environmental intensity (defined as the ratio of environmental impact over economic output) in a loose coupling of models to provide a sufficient level of integration while avoiding significant effort required for software development. This model construct was applied to the Motueka Catchment of New Zealand where several biophysical (riverine water quantity, sediment, E. coli faecal bacteria, trout numbers, nitrogen transport, marine productivity) models, a socio-economic (gross output, gross margin, job numbers) model, and an agent-based model were linked. An extreme set of land use scenarios (historic, present, and intensive) were applied to this modelling framework. Results suggest that the catchment is presently in a near optimal land use configuration that is unlikely to benefit from further intensification. This would quickly put stress on water quantity (at low flow) and water quality ( E. coli). To date, this model evaluation is based on a theoretical test that explores the logical implications of intensification at an unlikely extreme in order to assess the implications of likely growth

  2. Robust integration schemes for generalized viscoplasticity with internal-state variables. Part 2: Algorithmic developments and implementation

    NASA Technical Reports Server (NTRS)

    Li, Wei; Saleeb, Atef F.

    1995-01-01

    This two-part report is concerned with the development of a general framework for the implicit time-stepping integrators for the flow and evolution equations in generalized viscoplastic models. The primary goal is to present a complete theoretical formulation, and to address in detail the algorithmic and numerical analysis aspects involved in its finite element implementation, as well as to critically assess the numerical performance of the developed schemes in a comprehensive set of test cases. On the theoretical side, the general framework is developed on the basis of the unconditionally-stable, backward-Euler difference scheme as a starting point. Its mathematical structure is of sufficient generality to allow a unified treatment of different classes of viscoplastic models with internal variables. In particular, two specific models of this type, which are representative of the present start-of-art in metal viscoplasticity, are considered in applications reported here; i.e., fully associative (GVIPS) and non-associative (NAV) models. The matrix forms developed for both these models are directly applicable for both initially isotropic and anisotropic materials, in general (three-dimensional) situations as well as subspace applications (i.e., plane stress/strain, axisymmetric, generalized plane stress in shells). On the computational side, issues related to efficiency and robustness are emphasized in developing the (local) interative algorithm. In particular, closed-form expressions for residual vectors and (consistent) material tangent stiffness arrays are given explicitly for both GVIPS and NAV models, with their maximum sizes 'optimized' to depend only on the number of independent stress components (but independent of the number of viscoplastic internal state parameters). Significant robustness of the local iterative solution is provided by complementing the basic Newton-Raphson scheme with a line-search strategy for convergence. In the present second part of

  3. Robust integration schemes for generalized viscoplasticity with internal-state variables. Part 2: Algorithmic developments and implementation

    NASA Astrophysics Data System (ADS)

    Li, Wei; Saleeb, Atef F.

    1995-05-01

    This two-part report is concerned with the development of a general framework for the implicit time-stepping integrators for the flow and evolution equations in generalized viscoplastic models. The primary goal is to present a complete theoretical formulation, and to address in detail the algorithmic and numerical analysis aspects involved in its finite element implementation, as well as to critically assess the numerical performance of the developed schemes in a comprehensive set of test cases. On the theoretical side, the general framework is developed on the basis of the unconditionally-stable, backward-Euler difference scheme as a starting point. Its mathematical structure is of sufficient generality to allow a unified treatment of different classes of viscoplastic models with internal variables. In particular, two specific models of this type, which are representative of the present start-of-art in metal viscoplasticity, are considered in applications reported here; i.e., fully associative (GVIPS) and non-associative (NAV) models. The matrix forms developed for both these models are directly applicable for both initially isotropic and anisotropic materials, in general (three-dimensional) situations as well as subspace applications (i.e., plane stress/strain, axisymmetric, generalized plane stress in shells). On the computational side, issues related to efficiency and robustness are emphasized in developing the (local) interative algorithm. In particular, closed-form expressions for residual vectors and (consistent) material tangent stiffness arrays are given explicitly for both GVIPS and NAV models, with their maximum sizes 'optimized' to depend only on the number of independent stress components (but independent of the number of viscoplastic internal state parameters). Significant robustness of the local iterative solution is provided by complementing the basic Newton-Raphson scheme with a line-search strategy for convergence. In the present second part of

  4. Ashtekar variables

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay

    2015-05-01

    In the spirit of Scholarpedia, this invited article is addressed to students and younger researchers. It provides the motivation and background material, a summary of the main physical ideas, mathematical structures and results, and an outline of applications of the connection variables for general relativity. These variables underlie both the canonical/Hamiltonian and the spinfoam/path integral approaches in loop quantum gravity.

  5. Integration

    ERIC Educational Resources Information Center

    Kalyn, Brenda

    2006-01-01

    Integrated learning is an exciting adventure for both teachers and students. It is not uncommon to observe the integration of academic subjects such as math, science, and language arts. However, educators need to recognize that movement experiences in physical education also can be linked to academic curricula and, may even lead the…

  6. Increasing the Efficiency of LiDAR Based Forest Inventories: A Novel Approach for Integrating Variable Radius Inventory Plots with LiDAR Data.

    NASA Astrophysics Data System (ADS)

    Falkowski, M. J.; Fekety, P.; Silva, C. A.; Hudak, A. T.

    2015-12-01

    LiDAR data are increasingly applied to support forest inventory and assessment across a variety of spatial scales. Typically this is achieved by integrating LiDAR data with forest inventory collected at fixed radius forest inventory plots. A well-designed forest inventory, one that covers the full range of structural and compositional variation across the forest of interest, is costly especially when collecting fixed radius plot data. Variable radius plots offer an alternative inventory protocol that is more efficient in terms of both time and money. However, integrating variable radius plot data with LiDAR data is problematic because the plots have unknown sizes that vary with variation in tree size. This leads to a spatial mismatch between LiDAR metrics (e.g., mean height, canopy cover, density, etc.) and plot data, which ultimately translates into errors in LiDAR derived forest inventory predictions. We propose and evaluate and novel approach for integrating variable radius plot data into a LiDAR based forest inventories in two different forest systems, one in the inland northwest and another in the northern lakes states of the USA. The novel approach calculates LiDAR metrics by weighting the point cloud proportional to return height, mimicking the way in which variable radius plot data weights tree measurements by tree size. This could increase inventory sampling efficiency, allowing for the collection of a greater number of inventory plots, and ultimately improve the performance of LiDAR based inventories.

  7. Integrating interannual climate variability forecasts into weather-indexed crop insurance. The case of Malawi, Kenya and Tanzania

    NASA Astrophysics Data System (ADS)

    Vicarelli, M.; Giannini, A.; Osgood, D.

    2009-12-01

    In this study we explore the potential for re-insurance schemes built on regional climatic forecasts. We focus on micro-insurance contracts indexed on precipitation in 9 villages in Kenya, Tanzania (Eastern Africa) and Malawi (Southern Africa), and analyze the precipitation patterns and payouts resulting from El Niño Southern Oscillation (ENSO). The inability to manage future climate risk represents a “poverty trap” for several African regions. Weather shocks can potentially destabilize not only household, but also entire countries. Governments in drought-prone countries, donors and relief agencies are becoming aware of the importance to develop an ex-ante risk management framework for weather risk. Joint efforts to develop innovative mechanisms to spread and pool risk such as microinsurance and microcredit are currently being designed in several developing countries. While ENSO is an important component in modulating the rainfall regime in tropical Africa, the micro-insurance experiments currently under development to address drought risk among smallholder farmers in this region do not take into account ENSO monitoring or forecasting yet. ENSO forecasts could be integrated in the contracts and reinsurance schemes could be designed at the continental scale taking advantage of the different impact of ENSO on different regions. ENSO is associated to a bipolar precipitation pattern in Southern and Eastern Africa. La Niña years (i.e. Cold ENSO Episodes) are characterized by dry climate in Eastern Africa and wet climate in Southern Africa. During El Niño (or Warm Episode) the precipitation dipole is inverted, and Eastern Africa experiences increased probability for above normal rainfall (Halpert and Ropelewski, 1992, Journal of Climate). Our study represents the first exercise in trying to include ENSO forecasts in micro weather index insurance contract design. We analyzed the contracts payouts with respect to climate variability. In particular (i) we simulated

  8. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations

    SciTech Connect

    Jones, Lawrence E.

    2012-01-05

    A variety of studies have recently evaluated the opportunities for the large-scale integration of wind energy into the US power system. These studies have included, but are not limited to, "20 Percent Wind Energy by 2030: Increasing Wind Energy's Contribution to US Electricity Supply", the "Western Wind and Solar Integration Study", and the "Eastern Wind Integration and Transmission Study." Each of these US based studies have evaluated a variety of activities that can be undertaken by utilities to help integrate wind energy.

  9. Integrating Expert Knowledge with Data in Bayesian Networks: Preserving Data-Driven Expectations when the Expert Variables Remain Unobserved

    PubMed Central

    Constantinou, Anthony Costa; Fenton, Norman; Neil, Martin

    2016-01-01

    When developing a causal probabilistic model, i.e. a Bayesian network (BN), it is common to incorporate expert knowledge of factors that are important for decision analysis but where historical data are unavailable or difficult to obtain. This paper focuses on the problem whereby the distribution of some continuous variable in a BN is known from data, but where we wish to explicitly model the impact of some additional expert variable (for which there is expert judgment but no data). Because the statistical outcomes are already influenced by the causes an expert might identify as variables missing from the dataset, the incentive here is to add the expert factor to the model in such a way that the distribution of the data variable is preserved when the expert factor remains unobserved. We provide a method for eliciting expert judgment that ensures the expected values of a data variable are preserved under all the known conditions. We show that it is generally neither possible, nor realistic, to preserve the variance of the data variable, but we provide a method towards determining the accuracy of expertise in terms of the extent to which the variability of the revised empirical distribution is minimised. We also describe how to incorporate the assessment of extremely rare or previously unobserved events. PMID:27378822

  10. Integrating Expert Knowledge with Data in Bayesian Networks: Preserving Data-Driven Expectations when the Expert Variables Remain Unobserved.

    PubMed

    Constantinou, Anthony Costa; Fenton, Norman; Neil, Martin

    2016-09-01

    When developing a causal probabilistic model, i.e. a Bayesian network (BN), it is common to incorporate expert knowledge of factors that are important for decision analysis but where historical data are unavailable or difficult to obtain. This paper focuses on the problem whereby the distribution of some continuous variable in a BN is known from data, but where we wish to explicitly model the impact of some additional expert variable (for which there is expert judgment but no data). Because the statistical outcomes are already influenced by the causes an expert might identify as variables missing from the dataset, the incentive here is to add the expert factor to the model in such a way that the distribution of the data variable is preserved when the expert factor remains unobserved. We provide a method for eliciting expert judgment that ensures the expected values of a data variable are preserved under all the known conditions. We show that it is generally neither possible, nor realistic, to preserve the variance of the data variable, but we provide a method towards determining the accuracy of expertise in terms of the extent to which the variability of the revised empirical distribution is minimised. We also describe how to incorporate the assessment of extremely rare or previously unobserved events.

  11. Integrative variants, haplotypes and diplotypes of the CAPN3 and FRMD5 genes and several environmental exposures associate with serum lipid variables

    PubMed Central

    Guo, Tao; Yin, Rui-Xing; Pan, Ling; Yang, Shuo; Miao, Liu; Huang, Feng

    2017-01-01

    To determine whether the integrative variants, haplotypes and diplotypes of the calpain 3 (CAPN3) and the FERM domain containing 5 genes (FRMD5) and several environmental exposures are associated with an implication in lipid homeostasis, which are associated with cardiovascular risk. Genotyping of the CAPN3 rs4344713 and FRMD5 rs524908 was performed by Sanger sequencing in 1,640 subjects (Jing, 819 and Han, 821). Multivariate analyses of covariance models that adjusted by age, gender, body mass index (BMI), blood pressure and lifestyle (smoking and drinking), were constructed using variants, haplotypes and diplotypes of the CAPN3 rs4344713 and FRMD5 rs524908 as predictors and changes in lipid variables. Significant associations with low-density lipoprotein cholesterol and apolipoprotein (Apo) B were found. Linkage disequilibrium with each other showed the haplotype-phenotype associations with triglyceride and ApoA1. This study also suggested pleiotropic associations of the CAPN3-FRMD5 diplotypes with lipid variables. As potential confounders, diastolic blood pressure (DBP) and BMI were significantly associated with lipid variables. We conclude that integrative variants, haplotypes and diplotypes of the CAPN3 rs4344713 and FRMD5 rs524908, as well as DBP and BMI are associated with serum lipid variables in the Jing and Han populations. PMID:28332615

  12. Robust integral variable structure controller and pulse-width pulse-frequency modulated input shaper design for flexible spacecraft with mismatched uncertainty/disturbance.

    PubMed

    Hu, Qinglei

    2007-10-01

    This paper presents a dual-stage control system design method for the flexible spacecraft attitude maneuvering control by use of on-off thrusters and active vibration control by input shaper. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. As a stepping stone, an integral variable structure controller with the assumption of knowing the upper bounds of the mismatched lumped perturbation has been designed which ensures exponential convergence of attitude angle and angular velocity in the presence of bounded uncertainty/disturbances. To reconstruct estimates of the system states for use in a full information variable structure control law, an asymptotic variable structure observer is also employed. In addition, the thruster output is modulated in pulse-width pulse-frequency so that the output profile is similar to the continuous control histories. For actively suppressing the induced vibration, the input shaping technique is used to modify the existing command so that less vibration will be caused by the command itself, which only requires information about the vibration frequency and damping of the closed-loop system. The rationale behind this hybrid control scheme is that the integral variable structure controller can achieve good precision pointing, even in the presence of uncertainties/disturbances, whereas the shaped input attenuator is applied to actively suppress the undesirable vibrations excited by the rapid maneuvers. Simulation results for the spacecraft model show precise attitude control and vibration suppression.

  13. Integrating mixed-effect models into an architectural plant model to simulate inter- and intra-progeny variability: a case study on oil palm (Elaeis guineensis Jacq.).

    PubMed

    Perez, Raphaël P A; Pallas, Benoît; Le Moguédec, Gilles; Rey, Hervé; Griffon, Sébastien; Caliman, Jean-Pierre; Costes, Evelyne; Dauzat, Jean

    2016-08-01

    Three-dimensional (3D) reconstruction of plants is time-consuming and involves considerable levels of data acquisition. This is possibly one reason why the integration of genetic variability into 3D architectural models has so far been largely overlooked. In this study, an allometry-based approach was developed to account for architectural variability in 3D architectural models of oil palm (Elaeis guineensis Jacq.) as a case study. Allometric relationships were used to model architectural traits from individual leaflets to the entire crown while accounting for ontogenetic and morphogenetic gradients. Inter- and intra-progeny variabilities were evaluated for each trait and mixed-effect models were used to estimate the mean and variance parameters required for complete 3D virtual plants. Significant differences in leaf geometry (petiole length, density of leaflets, and rachis curvature) and leaflet morphology (gradients of leaflet length and width) were detected between and within progenies and were modelled in order to generate populations of plants that were consistent with the observed populations. The application of mixed-effect models on allometric relationships highlighted an interesting trade-off between model accuracy and ease of defining parameters for the 3D reconstruction of plants while at the same time integrating their observed variability. Future research will be dedicated to sensitivity analyses coupling the structural model presented here with a radiative balance model in order to identify the key architectural traits involved in light interception efficiency.

  14. Integrative clustering of multiple genomic data types using a joint latent variable model with application to breast and lung cancer subtype analysis.

    PubMed

    Shen, Ronglai; Olshen, Adam B; Ladanyi, Marc

    2009-11-15

    The molecular complexity of a tumor manifests itself at the genomic, epigenomic, transcriptomic and proteomic levels. Genomic profiling at these multiple levels should allow an integrated characterization of tumor etiology. However, there is a shortage of effective statistical and bioinformatic tools for truly integrative data analysis. The standard approach to integrative clustering is separate clustering followed by manual integration. A more statistically powerful approach would incorporate all data types simultaneously and generate a single integrated cluster assignment. We developed a joint latent variable model for integrative clustering. We call the resulting methodology iCluster. iCluster incorporates flexible modeling of the associations between different data types and the variance-covariance structure within data types in a single framework, while simultaneously reducing the dimensionality of the datasets. Likelihood-based inference is obtained through the Expectation-Maximization algorithm. We demonstrate the iCluster algorithm using two examples of joint analysis of copy number and gene expression data, one from breast cancer and one from lung cancer. In both cases, we identified subtypes characterized by concordant DNA copy number changes and gene expression as well as unique profiles specific to one or the other in a completely automated fashion. In addition, the algorithm discovers potentially novel subtypes by combining weak yet consistent alteration patterns across data types. R code to implement iCluster can be downloaded at http://www.mskcc.org/mskcc/html/85130.cfm

  15. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations. Executive Summary

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This is the executive summary for a report that provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  16. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This report provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  17. Best Practices in Grid Integration of Variable Wind Power: Summary of Recent US Case Study Results and Mitigation Measures

    SciTech Connect

    Smith, J. Charles; Parsons, Brian; Acker, Thomas; Milligan, Michael; Zavidil, Robert; Schuerger, Matthew; DeMeo, Edgar

    2010-01-22

    This paper will summarize results from a number of utility wind integration case studies conducted recently in the US, and outline a number of mitigation measures based on insights from those studies.

  18. Harmonising and semantically linking key variables from in-situ observing networks of an Integrated Atlantic Ocean Observing System, AtlantOS

    NASA Astrophysics Data System (ADS)

    Darroch, Louise; Buck, Justin

    2017-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements at regional, national and international scales. The EU Horizon 2020 AtlantOS project aims to deliver an advanced framework for the development of an Integrated Atlantic Ocean Observing System that strengthens the Global Ocean Observing System (GOOS) and contributes to the aims of the Galway Statement on Atlantic Ocean Cooperation. One goal is to ensure that data from different and diverse in-situ observing networks are readily accessible and useable to a wider community, including the international ocean science community and other stakeholders in this field. To help achieve this goal, the British Oceanographic Data Centre (BODC) produced a parameter matrix to harmonise data exchange, data flow and data integration for the key variables acquired by multiple in-situ AtlantOS observing networks such as ARGO, Seafloor Mapping and OceanSITES. Our solution used semantic linking of controlled vocabularies and metadata for parameters that were "mappable" to existing EU and international standard vocabularies. An AtlantOS Essential Variables list of terms (aggregated level) based on Global Climate Observing System (GCOS) Essential Climate Variables (ECV), GOOS Essential Ocean Variables (EOV) and other key network variables was defined and published on the Natural Environment Research Council (NERC) Vocabulary Server (version 2.0) as collection A05 (http://vocab.nerc.ac.uk/collection/A05/current/). This new vocabulary was semantically linked to standardised metadata for observed properties and units that had been validated by the AtlantOS community: SeaDataNet parameters (P01), Climate and Forecast (CF) Standard Names (P07) and SeaDataNet units (P06). Observed properties were mapped to biological entities from the internationally assured AphiaID from the WOrld Register of Marine Species (WoRMS), http

  19. The Functional Segregation and Integration Model: Mixture Model Representations of Consistent and Variable Group-Level Connectivity in fMRI.

    PubMed

    Churchill, Nathan W; Madsen, Kristoffer; Mørup, Morten

    2016-10-01

    The brain consists of specialized cortical regions that exchange information between each other, reflecting a combination of segregated (local) and integrated (distributed) processes that define brain function. Functional magnetic resonance imaging (fMRI) is widely used to characterize these functional relationships, although it is an ongoing challenge to develop robust, interpretable models for high-dimensional fMRI data. Gaussian mixture models (GMMs) are a powerful tool for parcellating the brain, based on the similarity of voxel time series. However, conventional GMMs have limited parametric flexibility: they only estimate segregated structure and do not model interregional functional connectivity, nor do they account for network variability across voxels or between subjects. To address these issues, this letter develops the functional segregation and integration model (FSIM). This extension of the GMM framework simultaneously estimates spatial clustering and the most consistent group functional connectivity structure. It also explicitly models network variability, based on voxel- and subject-specific network scaling profiles. We compared the FSIM to standard GMM in a predictive cross-validation framework and examined the importance of different model parameters, using both simulated and experimental resting-state data. The reliability of parcellations is not significantly altered by flexibility of the FSIM, whereas voxel- and subject-specific network scaling profiles significantly improve the ability to predict functional connectivity in independent test data. Moreover, the FSIM provides a set of interpretable parameters to characterize both consistent and variable aspects functional connectivity structure. As an example of its utility, we use subject-specific network profiles to identify brain regions where network expression predicts subject age in the experimental data. Thus, the FSIM is effective at summarizing functional connectivity structure in group

  20. What Information Is Necessary for Speech Categorization? Harnessing Variability in the Speech Signal by Integrating Cues Computed Relative to Expectations

    ERIC Educational Resources Information Center

    McMurray, Bob; Jongman, Allard

    2011-01-01

    Most theories of categorization emphasize how continuous perceptual information is mapped to categories. However, equally important are the informational assumptions of a model, the type of information subserving this mapping. This is crucial in speech perception where the signal is variable and context dependent. This study assessed the…

  1. Correlates of Student Performance in the Science Olympiad: The Test of Integrated Process Skills and Other Variables.

    ERIC Educational Resources Information Center

    Baird, William E.; And Others

    The Test of Integrated Process Skills (TIPS) was administered to 667 students in grades 9-12 who were registering to participate in a regional science Olympiad on a southern university campus in February 1988. Each student's score on the test was correlated with subsequent performance in one or more of the 11 Olympiad events. Of the 667 students…

  2. Integrated Marketing Communications (IMC) Variables That Influence Perceived Return on Investment (ROI) in Higher Education: Chief Marketing Officers' Perceptions

    ERIC Educational Resources Information Center

    King, Adrienne L.

    2013-01-01

    This study examines the relationship of the level of Integrated Marketing Communications (IMC) implementation, level of open systems and change in state appropriations on perceived return on investment (ROI) in U.S. public higher education institutions (HEIs). Designed to provide HEI leaders with data to more accurately determine the best IMC…

  3. A Study of Semiotic Registers in the Development of the Definite Integral of Functions of Two and Three Variables

    ERIC Educational Resources Information Center

    McGee, Daniel Lee; Martinez-Planell, Rafael

    2014-01-01

    Tracing the path from a numerical Riemann sum approximating the area under a curve to a definite integral representing the precise area in various texts and online presentations, we found 3 semiotic registers that are used: the geometric register, the numerical register, and the symbolic register. The symbolic register had 3 representations: an…

  4. A Study of Semiotic Registers in the Development of the Definite Integral of Functions of Two and Three Variables

    ERIC Educational Resources Information Center

    McGee, Daniel Lee; Martinez-Planell, Rafael

    2014-01-01

    Tracing the path from a numerical Riemann sum approximating the area under a curve to a definite integral representing the precise area in various texts and online presentations, we found 3 semiotic registers that are used: the geometric register, the numerical register, and the symbolic register. The symbolic register had 3 representations: an…

  5. Institutional Variability in Faculty Conformity to the Norms of Science: A Force of Integration or Fragmentation in the Academic Profession?

    ERIC Educational Resources Information Center

    Braxton, John M.

    1989-01-01

    A study to determine whether faculty conformity to the four norms of science identified by Merton are integrating mechanisms or whether they are forces of fragmentation is discussed. The four norms are identified: universalism, communality, disinterestedness, and organized skepticism. (Author/MLW)

  6. Integrated Marketing Communications (IMC) Variables That Influence Perceived Return on Investment (ROI) in Higher Education: Chief Marketing Officers' Perceptions

    ERIC Educational Resources Information Center

    King, Adrienne L.

    2013-01-01

    This study examines the relationship of the level of Integrated Marketing Communications (IMC) implementation, level of open systems and change in state appropriations on perceived return on investment (ROI) in U.S. public higher education institutions (HEIs). Designed to provide HEI leaders with data to more accurately determine the best IMC…

  7. Integrating Algebra and Proof in High School: Students' Work with Multiple Variables and a Single Parameter in a Proof Context

    ERIC Educational Resources Information Center

    Martinez, Mara V.; Castro Superfine, Alison

    2012-01-01

    In the United States, researchers argue that proof is largely concentrated in the domain of high school geometry, thus providing students a distorted image of what proof entails, which is at odds with the central role that proof plays in mathematics. Despite the centrality of proof, there is a lack of studies addressing how to integrate proof into…

  8. Modeling short-term variability of semivolatile organic chemicals in air at a local scale: an integrated modeling approach.

    PubMed

    Morselli, Melissa; Ghirardello, Davide; Semplice, Matteo; Di Guardo, Antonio

    2011-05-01

    Monitoring campaigns from different locations have recently shown how air concentrations of persistent semivolatile contaminants such as polychlorinated biphenyls (PCBs) often exhibit short-term (less than 24 h) variations. The observed patterns have been ascribed to different factors, such as temperature-mediated air-surface exchange and variability of planetary boundary layer (PBL) height and dynamics. Here, we present a new modeling approach developed in order to investigate the short-term variability in air concentrations of organic pollutants at a local scale. A new dynamic multimedia box model is supplied by a meteorological preprocessor (AERMET) with hourly values of air compartment height and wind speed. The resulting model is tested against an existing dataset of PCB air concentrations measured in Zurich, Switzerland. Results show the importance of such modeling approach in elucidating the short- and long-term behavior of semivolatile contaminants in the air/soil system.

  9. The variable pressure supercritical Rankine cycle for integrated natural gas and power production from the geopressured geothermal resource

    NASA Astrophysics Data System (ADS)

    Goldsberry, F. L.

    1982-03-01

    A small-scale power plant cycle that utilizes both a variable pressure vaporizer (heater) and a floating pressure (and temperature) air-cooled condenser is described. Further, it defends this choice on the basis of classical thermodynamics and minimum capital cost by supporting these conclusions with actual comparative examples. The application suggested is for the geopressured geothermal resource. The arguments cited in this application apply to any process (petrochemical, nuclear, etc.) involving waste heat recovery.

  10. MILP model for integrated balancing and sequencing mixed-model two-sided assembly line with variable launching interval and assignment restrictions

    NASA Astrophysics Data System (ADS)

    Azmi, N. I. L. Mohd; Ahmad, R.; Zainuddin, Z. M.

    2017-09-01

    This research explores the Mixed-Model Two-Sided Assembly Line (MMTSAL). There are two interrelated problems in MMTSAL which are line balancing and model sequencing. In previous studies, many researchers considered these problems separately and only few studied them simultaneously for one-sided line. However in this study, these two problems are solved simultaneously to obtain more efficient solution. The Mixed Integer Linear Programming (MILP) model with objectives of minimizing total utility work and idle time is generated by considering variable launching interval and assignment restriction constraint. The problem is analysed using small-size test cases to validate the integrated model. Throughout this paper, numerical experiment was conducted by using General Algebraic Modelling System (GAMS) with the solver CPLEX. Experimental results indicate that integrating the problems of model sequencing and line balancing help to minimise the proposed objectives function.

  11. Beyond long memory in heart rate variability: An approach based on fractionally integrated autoregressive moving average time series models with conditional heteroscedasticity

    NASA Astrophysics Data System (ADS)

    Leite, Argentina; Paula Rocha, Ana; Eduarda Silva, Maria

    2013-06-01

    Heart Rate Variability (HRV) series exhibit long memory and time-varying conditional variance. This work considers the Fractionally Integrated AutoRegressive Moving Average (ARFIMA) models with Generalized AutoRegressive Conditional Heteroscedastic (GARCH) errors. ARFIMA-GARCH models may be used to capture and remove long memory and estimate the conditional volatility in 24 h HRV recordings. The ARFIMA-GARCH approach is applied to fifteen long term HRV series available at Physionet, leading to the discrimination among normal individuals, heart failure patients, and patients with atrial fibrillation.

  12. Path integral molecular dynamics combined with discrete-variable-representation approach: the effect of solvation structures on vibrational spectra of Cl 2 in helium clusters

    NASA Astrophysics Data System (ADS)

    Takayanagi, Toshiyuki; Shiga, Motoyuki

    2002-08-01

    The structures and vibrational frequencies of Cl 2-helium clusters have been studied using the path integral molecular dynamics method combined with the discrete-variable-representation approach. It is found that the Cl 2-helium clusters form clear shell structures comprised of rings around the Cl 2 bond. The vibrational frequencies calculated show a monotonically increasing red shift with an increase in cluster size. It can be concluded that the first solvation shell and its density around T-shaped configurations play the most important role in the observed frequency shifts.

  13. An integrated observational and model-based analysis of the hydrologic response of prairie pothole systems to variability in climate

    NASA Astrophysics Data System (ADS)

    Liu, Ganming; Schwartz, Franklin W.

    2011-02-01

    We developed a hydrologic model capable of simulating pothole complexes composed of tens of thousands or more individual closed-basin water bodies. It was applied to simulate the hydrologic response of a prairie pothole complex to climatic variability over a 105 year period (1901-2005) in an area of the Prairie Pothole Region in North Dakota. The model was calibrated and validated with a genetic algorithm by comparing the simulated results with observed power law relationships on water area-frequency derived from Landsat images and a 27 year record of water depths from six wetlands in the Cottonwood Lake area. The simulated behavior in water area and water body frequency showed good agreement with the observations under average, dry, and wet conditions. Analysis of simulation results over the last century showed that the power laws changed intra-annually and interannually as a function of climate. Major droughts and deluges can produce marked variability in the power law function (e.g., up to 1.5 orders of magnitude variability in intercept from the extreme Dust Bowl drought to the extreme 1993-2001 deluge). Analyses also revealed the frequency of occurrence of small potholes and puddles did not follow pure power law behavior and that details of the departure from linear behavior were closely related to the climatic conditions. A general equation, which encompasses both the linear power law segment for large potholes and nonlinear unimodal body for small potholes and puddles, was used to build conceptual models to describe how the numbers of water bodies as a function of water area respond to fluctuations in climate.

  14. Between-session intra-individual variability in sustained, selective, and integrational non-linguistic attention in aphasia.

    PubMed

    Villard, Sarah; Kiran, Swathi

    2015-01-01

    A number of studies have identified impairments in one or more types/aspects of attention processing in patients with aphasia (PWA) relative to healthy controls; person-to-person variability in performance on attention tasks within the PWA group has also been noted. Studies using non-linguistic stimuli have found evidence that attention is impaired in this population even in the absence of language processing demands. An underlying impairment in non-linguistic, or domain-general, attention processing could have implications for the ability of PWA to attend during therapy sessions, which in turn could impact long-term treatment outcomes. With this in mind, this study aimed to systematically examine the effect of task complexity on reaction time (RT) during a non-linguistic attention task, in both PWA and controls. Additional goals were to assess the effect of task complexity on between-session intra-individual variability (BS-IIV) in RT and to examine inter-individual differences in BS-IIV. Eighteen PWA and five age-matched neurologically healthy controls each completed a novel computerized non-linguistic attention task measuring five types of attention on each of four different non-consecutive days. A significant effect of task complexity on both RT and BS-IIV in RT was found for the PWA group, whereas the control group showed a significant effect of task complexity on RT but not on BS-IIV in RT. Finally, in addition to these group-level findings, it was noted that different patients exhibited different patterns of BS-IIV, indicating the existence of inter-individual variability in BS-IIV within the PWA group. Results may have implications for session-to-session fluctuations in attention during language testing and therapy for PWA.

  15. What information is necessary for speech categorization? Harnessing variability in the speech signal by integrating cues computed relative to expectations

    PubMed Central

    McMurray, Bob; Jongman, Allard

    2012-01-01

    Most theories of categorization emphasize how continuous perceptual information is mapped to categories. However, equally important is the informational assumptions of a model, the type of information subserving this mapping. This is crucial in speech perception where the signal is variable and context-dependent. This study assessed the informational assumptions of several models of speech categorization, in particular, the number of cues that are the basis of categorization and whether these cues represent the input veridically or have undergone compensation. We collected a corpus of 2880 fricative productions (Jongman, Wayland & Wong, 2000) spanning many talker- and vowel-contexts and measured 24 cues for each. A subset was also presented to listeners in an 8AFC phoneme categorization task. We then trained a common classification model based on logistic regression to categorize the fricative from the cue values, and manipulated the information in the training set to contrast 1) models based on a small number of invariant cues; 2) models using all cues without compensation, and 3) models in which cues underwent compensation for contextual factors. Compensation was modeled by Computing Cues Relative to Expectations (C-CuRE), a new approach to compensation that preserves fine-grained detail in the signal. Only the compensation model achieved a similar accuracy to listeners, and showed the same effects of context. Thus, even simple categorization metrics can overcome the variability in speech when sufficient information is available and compensation schemes like C-CuRE are employed. PMID:21417542

  16. An integrated approach for spatio-temporal variability analysis of wetlands: a case study of Abaya and Chamo lakes, Ethiopia.

    PubMed

    Tibebu Kassawmar, N; Ram Mohan Rao, K; Lemlem Abraha, G

    2011-09-01

    Starting with the intensification of irrigation activities in the beginning of 1980s in Abaya and Chamo lakes area, the decreasing water inflow to the lakes caused denudation of the wetlands. The ecological situation in the lake region changed significantly during last four decades. The lakes and associated wetlands change have been studied using Landsat MSS (1973), Landsat TM (1986), and Ladsat ETM (2000) satellite imagery. Along with satellite imagery, other hydro-meteorological data were collected and hydro-meteorological data analyses were done to assess the variability of wetlands. From these data, lakes morphometric property estimation at different time series and water balance analysis for both lakes were done. Wetlands are mapped from the TCT image and these maps are subject to change detection to see the temporal and spatial variability of the wetlands. Moreover, the lake-morphometric area and volume variation have been studied. The result showed that between 1986 and 2000, a significant reduction has been observed but lesser than the previous decades (6.4 km(2)). The identified reason behind this change is that the free settlement and shoreline cultivation of the wetlands causing the soil erosion and eventually adds the sediment to the wetlands.

  17. Host Lipid and Temperature as Important Screening Variables for Crystallizing Integral Membrane Proteins in Lipidic Mesophases. Trials with Diacylglycerol Kinase

    PubMed Central

    Li, Dianfan; Shah, Syed T. A.; Caffrey, Martin

    2013-01-01

    A systematic study of the crystallization of an α-helical, integral membrane enzyme, diacylglycerol kinase, DgkA, using the lipidic cubic mesophase or in meso method is described. These trials have resulted in the production of blocky, rhombohedron-shaped crystals of diffraction quality currently in use for structure determination. Dramatic improvements in crystal quality were obtained when the identity of the lipid used to form the mesophase bilayer into which the protein was reconstituted as a prelude to crystallogenesis was varied. These monoacylglycerol lipids incorporated fatty acyl chains ranging from 14 to 18 carbon atoms long with cis olefinic bonds located toward the middle of the chain. Best crystals were obtained with a lipid that had an acyl chain 15 carbon atoms long with the double bond between carbons 7 and 8. It is speculated that the effectiveness of this lipid derives from hydrophobic mismatch between the target integral membrane protein and the bilayer of the host mesophase. Low temperature (4 °C) worked in concert with the short chain lipid to provide high quality crystals. Recommended screening strategies for crystallizing membrane proteins that include host lipid type and low temperature are made on the basis of this and related in meso crystallization trials. PMID:23956688

  18. INTEGRAL Spectral Variability Study of the Atoll 4U 1820-30: First Detection of Hard X-Ray Emission

    NASA Astrophysics Data System (ADS)

    Tarana, A.; Bazzano, A.; Ubertini, P.; Zdziarski, A. A.

    2007-01-01

    We study the 4-200 keV spectral and temporal behavior of the low-mass X-ray binary 4U 1820-30 with INTEGRAL during 2003-2005. This source as been observed in both the soft (banana) and hard (island) spectral states. A high-energy tail, above 50 keV, in the hard state has been observed for the first time. This places the source in the category of X-ray bursters showing high-energy emission. The tail can be modeled as a soft power-law component, with the photon index of ~=2.4, on top of thermal Comptonization emission from a plasma with electron temperature kTe~=6 keV and optical depth τ~=4. Alternatively, but at a poorer goodness of fit, the hard-state broadband spectrum can be accounted for by emission from a hybrid, thermal-nonthermal, plasma. During this monitoring the source spent most of the time in the soft state, usual for this source, and the >~4 keV spectra are described by thermal Comptonization with kTe~=3 keV and τ~=6-7. INTEGRAL is an ESA project with instruments and Science Data Centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), Czech Republic, and Poland, and with the participation of Russia and the USA.

  19. A variable timestep generalized Runge-Kutta method for the numerical integration of the space-time diffusion equations

    SciTech Connect

    Aviles, B.N.; Sutton, T.M.; Kelly, D.J. III.

    1991-09-01

    A generalized Runge-Kutta method has been employed in the numerical integration of the stiff space-time diffusion equations. The method is fourth-order accurate, using an embedded third-order solution to arrive at an estimate of the truncation error for automatic timestep control. The efficiency of the Runge-Kutta method is enhanced by a block-factorization technique that exploits the sparse structure of the matrix system resulting from the space and energy discretized form of the time-dependent neutron diffusion equations. Preliminary numerical evaluation using a one-dimensional finite difference code shows the sparse matrix implementation of the generalized Runge-Kutta method to be highly accurate and efficient when compared to an optimized iterative theta method. 12 refs., 5 figs., 4 tabs.

  20. The extrapolated explicit midpoint scheme for variable order and step size controlled integration of the Landau-Lifschitz-Gilbert equation

    NASA Astrophysics Data System (ADS)

    Exl, Lukas; Mauser, Norbert J.; Schrefl, Thomas; Suess, Dieter

    2017-10-01

    A practical and efficient scheme for the higher order integration of the Landau-Lifschitz-Gilbert (LLG) equation is presented. The method is based on extrapolation of the two-step explicit midpoint rule and incorporates adaptive time step and order selection. We make use of a piecewise time-linear stray field approximation to reduce the necessary work per time step. The approximation to the interpolated operator is embedded into the extrapolation process to keep in step with the hierarchic order structure of the scheme. We verify the approach by means of numerical experiments on a standardized NIST problem and compare with a higher order embedded Runge-Kutta formula. The efficiency of the presented approach increases when the stray field computation takes a larger portion of the costs for the effective field evaluation.

  1. Integrity of immunoglobulin variable region is supported by GANP during AID-induced somatic hypermutation in germinal center B cells.

    PubMed

    Eid, Mohammed Mansour Abbas; Shimoda, Mayuko; Singh, Shailendra Kumar; Almofty, Sarah Ameen; Pham, Phuong; Goodman, Myron F; Maeda, Kazuhiko; Sakaguchi, Nobuo

    2017-05-24

    Immunoglobulin (Ig) affinity maturation depends on somatic hypermutation (SHM) in variable (V) regions initiated by activation-induced cytidine deaminase (AID). AID induces transition mutations by C→U deamination on both strands, causing C:G→T:A. Error-prone repairs of U by base excision and mismatch repairs create transversion mutations at C/G and mutations at A/T sites. In Neuberger's model, it remained to clarify how transition/transversion repair is regulated. We investigate role of AID-interacting GANP (germinal-center associated nuclear protein) in IgV SHM profile. GANP enhances transition mutation of nontranscribed-strand G and reduces mutation at A, restricted to GYW of AID hotspot motif. It reduces DNA polymerase η hotspot mutations associated with mismatch repairs followed by uracil-DNA glycosylase. Mutation comparison between IgV complementary and framework regions by Statistical Bayesian estimation demonstrates GANP supports to preserve IgV framework region genomic sequences. GANP works to maintain antibody structure by reducing drastic changes in IgV framework region in affinity maturation. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society for Immunology.

  2. Energy Storage for Variable Renewable Energy Resource Integration - A Regional Assessment for the Northwest Power Pool (NWPP)

    SciTech Connect

    Kintner-Meyer, Michael CW; Jin, Chunlian; Balducci, Patrick J.; Elizondo, Marcelo A.; Guo, Xinxin; Nguyen, Tony B.; Tuffner, Francis K.; Viswanathan, Vilayanur V.

    2011-03-20

    This paper addresses the following key questions in the discussion on the integration of renewable energy resources in the Pacific Northwest power grid: a) what will be the future balancing requirement to accommodate a simulated expansion of wind energy resources from 3.3 GW in 2008 to 14.4 GW in 2019 in the Northwest Power Pool (NWPP), and b) what are the most cost effective technological solutions for meeting the balancing requirements in the Northwest Power Pool (NWPP). A life-cycle analysis was performed to assess the least-cost technology option for meeting the new balancing requirement. The technologies considered in this study include conventional turbines (CT), sodium sulfur (NaS) batteries, lithium ion (Li-ion) batteries, pumped hydro energy storage (PH), and demand response (DR). Hybrid concepts that combine 2 or more of the technologies above are also evaluated. This analysis was performed with collaboration by the Bonneville Power Administration and funded by the Energy Storage Systems Program of the U.S. Department of Energy.

  3. Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation

    SciTech Connect

    Eto, Joseph H.; Undrill, John; Mackin, Peter; Daschmans, Ron; Williams, Ben; Haney, Brian; Hunt, Randall; Ellis, Jeff; Illian, Howard; Martinez, Carlos; O'Malley, Mark; Coughlin, Katie; LaCommare, Kristina Hamachi

    2010-12-20

    An interconnected electric power system is a complex system that must be operated within a safe frequency range in order to reliably maintain the instantaneous balance between generation and load. This is accomplished by ensuring that adequate resources are available to respond to expected and unexpected imbalances and restoring frequency to its scheduled value in order to ensure uninterrupted electric service to customers. Electrical systems must be flexible enough to reliably operate under a variety of"change" scenarios. System planners and operators must understand how other parts of the system change in response to the initial change, and need tools to manage such changes to ensure reliable operation within the scheduled frequency range. This report presents a systematic approach to identifying metrics that are useful for operating and planning a reliable system with increased amounts of variable renewable generation which builds on existing industry practices for frequency control after unexpected loss of a large amount of generation. The report introduces a set of metrics or tools for measuring the adequacy of frequency response within an interconnection. Based on the concept of the frequency nadir, these metrics take advantage of new information gathering and processing capabilities that system operators are developing for wide-area situational awareness. Primary frequency response is the leading metric that will be used by this report to assess the adequacy of primary frequency control reserves necessary to ensure reliable operation. It measures what is needed to arrest frequency decline (i.e., to establish frequency nadir) at a frequency higher than the highest set point for under-frequency load shedding within an interconnection. These metrics can be used to guide the reliable operation of an interconnection under changing circumstances.

  4. Agricultural Decision-Making In Indonesia With ENSO Variability: Integrating Climate Science, Risk Assessment, And Policy Analysis

    NASA Astrophysics Data System (ADS)

    Battisti, D. S.; Naylor, R. L.; Vimont, D. J.; Falcon, W. P.

    2006-12-01

    We present our current research to show how climate science can be used to inform agricultural decision- making at the policy level. Our project, funded by the Human and Social Dimensions Program at NSF, focuses on Indonesia, where agricultural production is strongly influenced by the annual cycle of precipitation and by year-to-year variations in the annual cycle caused by El Nino-Southern Oscillation (ENSO) dynamics, and where the combined forces of ENSO and global warming are likely to have dramatic effects on agricultural production and food security for tens of millions of people. The two main goals of the research are: 1) to project the impacts of global warming on Indonesian agriculture by estimating changes in mean climate and climate variability (i.e., ENSO); and 2) to analyze how these projections (including relevant bands of uncertainty) can be used to inform agricultural decision-making processes. To accomplish the first goal, we developed a set of regional climate scenarios for Indonesia in the mid-21st century. These scenarios are developed using (i) the large-scale climate changes projected from the collection of climate models used in the IPCC process, (ii) select experiments with an atmospheric general circulation model, and (iii) a newly developed downscaling model that links the large-scale circulation to the regional scale climate. These scenarios are then used to assess the influence of global warming on the annual climate cycle and on ENSO-induced changes in precipitation and agricultural production in Indonesia. (The link between projected crop production and climate is established from our previous work). The second goal is accomplished by developing a risk assessment framework that links the probabilities of climate change to its potential consequences on agriculture, taking into account various adaptation measures, such as the development of drought tolerant crop varieties and irrigation investment. The model template we have designed and

  5. Effect of the spatiotemporal variability of rainfall inputs in water quality integrated catchment modelling for dissolved oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Moreno Ródenas, Antonio Manuel; Cecinati, Francesca; ten Veldhuis, Marie-Claire; Langeveld, Jeroen; Clemens, Francois

    2016-04-01

    Maintaining water quality standards in highly urbanised hydrological catchments is a worldwide challenge. Water management authorities struggle to cope with changing climate and an increase in pollution pressures. Water quality modelling has been used as a decision support tool for investment and regulatory developments. This approach led to the development of integrated catchment models (ICM), which account for the link between the urban/rural hydrology and the in-river pollutant dynamics. In the modelled system, rainfall triggers the drainage systems of urban areas scattered along a river. When flow exceeds the sewer infrastructure capacity, untreated wastewater enters the natural system by combined sewer overflows. This results in a degradation of the river water quality, depending on the magnitude of the emission and river conditions. Thus, being capable of representing these dynamics in the modelling process is key for a correct assessment of the water quality. In many urbanised hydrological systems the distances between draining sewer infrastructures go beyond the de-correlation length of rainfall processes, especially, for convective summer storms. Hence, spatial and temporal scales of selected rainfall inputs are expected to affect water quality dynamics. The objective of this work is to evaluate how the use of rainfall data from different sources and with different space-time characteristics affects modelled output concentrations of dissolved oxygen in a simplified ICM. The study area is located at the Dommel, a relatively small and sensitive river flowing through the city of Eindhoven (The Netherlands). This river stretch receives the discharge of the 750,000 p.e. WWTP of Eindhoven and from over 200 combined sewer overflows scattered along its length. A pseudo-distributed water quality model has been developed in WEST (mikedhi.com); this is a lumped-physically based model that accounts for urban drainage processes, WWTP and river dynamics for several

  6. Novel Integration of a 6t Cryogen-Free Magneto-Optical System with a Variable Temperature Sample Using a Single Cryocooler

    NASA Astrophysics Data System (ADS)

    Berryhill, A. B.; Coffey, D. M.; McGhee, R. W.; Burkhardt, E. E.

    2008-03-01

    Cryomagnetics' new "C-Mag Optical" Magneto-Optic Property Measurement System is a versatile materials and device characterization system that allows the researcher to simultaneously control the applied magnetic field and temperature of a sample while studying its electrical and optic properties. The system integrates a totally liquid cryogen-free 6T superconducting split-pair magnet with a variable temperature sample space, both cooled using a single 4.2K pulse tube refrigerator. To avoid warming the magnet when operating a sample at elevated temperatures, a novel heat switch was developed. The heat switch allows the sample temperature to be varied from 10K to 300K while maintaining the magnet at 4.2K or below. In this paper, the design and performance of the overall magnet system and the heat switch will be presented. New concepts for the next generation system will also be discussed.

  7. A model study of the vertically integrated transport variability through the Yucatan Channel: Role of Loop Current evolution and flow compensation around Cuba

    NASA Astrophysics Data System (ADS)

    Lin, Yuehua; Greatbatch, Richard J.; Sheng, Jinyu

    2009-08-01

    The relationship between Loop Current intrusion in the Gulf of Mexico and vertically integrated transport variations through the Yucatan Channel is examined using models and the available observations. Transport in the model is found to be a minimum when the Loop Current intrudes strongly into the Gulf of Mexico, typically just before a ring is shed, and to be a maximum during the next growth phase in association with the buildup of warm water off the northwest coast of Cuba. We argue that the transport variations are part of a "compensation effect" in which transport variations through the Yucatan Channel are at least partly compensated by flow around Cuba. Numerical experiments show that the transport variations result from the interaction between the density anomalies associated with Loop Current intrusion and the variable bottom topography. The compensation effect is also shown to operate at shorter time scales (less than 30 days) in association with wind forcing.

  8. MODIS time series analysis as a tool for forest drought detection in Catalonia (NE Iberian Peninsula): integration of remote sensing and climatic variables.

    NASA Astrophysics Data System (ADS)

    Domingo, Cristina; Cristóbal, Jordi; Ninyerola, Miquel; Pons, Xavier

    2013-04-01

    Climate warming may accelerate the hydrological cycle as a result of enhanced evaporative demand in some regions where water is not limiting. However, the combination of warmer temperatures with constant or reduced precipitation in other regions may lead to a large decrease in water availability for natural and agricultural systems as well as for human needs, especially in arid or semiarid areas such as the Mediterranean basin, increasing drought occurrence. Nowadays drought remains a phenomenon that affects a wide variety of natural areas in many parts of the globe. Droughts are considered the abiotic factor with most harmful effects on forest areas, thus it is especially important to identify the locations with highest potential impact. Its temporal and spatial distribution, as well as the different types of drought defined, makes difficult its prediction and the impact degree that their appearance involve. Climatic drought, characterized by a temporal sequence with a higher frequency of atmospheric conditions that are unfavorable to the development of precipitation over a region, is the trigger of the process associated with the risk of biological drought. One methodology used to identify periods of climatic drought is mainly based on the analysis of climatic variables such as precipitation or temperature. However, these analyses don't take into account the physiological state of vegetation, a highly important variable that should be used to monitor the status of forest ecosystems vulnerable to droughts. In this work we evaluate the potential of satellite images regarding the identification of Mediterranean forest areas that could potentially have had a maximum affection during drought periods. A long temporal series of images of MODIS sensors onboard TERRA satellite, for the period 2000-2011 together with climatic data from the Digital Atlas of Catalonia were integrated to detect drought in forest canopies. This integration may provide a readily applicable

  9. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean): an integrative analysis of spatial variability and biophysical forcings

    NASA Astrophysics Data System (ADS)

    Forest, A.; Babin, M.; Stemmann, L.; Picheral, M.; Sampei, M.; Fortier, L.; Gratton, Y.; Bélanger, S.; Devred, E.; Sahlin, J.; Doxaran, D.; Joux, F.; Ortega-Retuerta, E.; Jeffrey, W. H.; Martín, J.; Gasser, B.; Miquel, J. C.

    2012-08-01

    A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here, we combine mooring times-series, ship-based measurements and remote-sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC) across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their biophysical determinants in summer. Flux data were obtained with sediment traps and via a regional empirical algorithm applied to particle size-distributions (17 classes from 0.08-4.2 mm) measured by an Underwater Vision Profiler 5. Redundancy analyses and forward selection of abiotic/biotic parameters, linear trends, and spatial structures (i.e. principal coordinates of neighbor matrices, PCNM), were conducted to partition the variation of POC flux size-classes. Flux variability was explained at 69.5 % by the addition of a linear temporal trend, 7 significant PCNM and 9 biophysical variables. The interaction of all these factors explained 27.8 % of the variability. The first PCNM canonical axis (44.4 % of spatial variance) reflected a shelf-basin gradient controlled by bottom depth and ice concentration (p < 0.01), but a complex assemblage of fine-to-broad scale patterns was also identified. Among biophysical parameters, bacterial production and northeasterly wind (upwelling-favorable) were the two strongest explanatory variables (r2 cum. = 0.37), suggesting that bacteria were associated with sinking material, which was itself partly linked to upwelling-induced productivity. The second most important spatial structure corresponded actually to the two areas where shelf break upwelling is known to occur under easterlies. Copepod biomass was negatively correlated (p < 0.05) with vertical POC fluxes, implying that metazoans played a significant role in the regulation of export fluxes. The low fractal dimension of settling particles (1

  10. Methods for Addressing Uncertainty and Variability to Characterize Potential Health Risk from Trichloroethylene-Contaminated Ground Water at Beale Air Force Base in California:Integration of Uncertainty and Variability in Pharmacokinetics and Dose-Response

    SciTech Connect

    Bogen, K T

    2001-05-24

    Traditional estimates of health risk are typically inflated, particularly if cancer is the dominant endpoint and there is fundamental uncertainty as to mechanism(s) of action. Risk is more realistically characterized if it accounts for joint uncertainty and interindividual variability within a systematic probabilistic framework to integrate the joint effects on risk of distributed parameters of all (linear as well as nonlinear) risk-extrapolation models involved. Such a framework was used to characterize risks to potential future residents posed by trichloroethylene (TCE) in ground water at an inactive landfill site on Beale Air Force Base in California. Variability and uncertainty were addressed in exposure-route-specific estimates of applied dose, in pharmacokinetically based estimates of route-specific metabolized fractions of absorbed TCE, and in corresponding biologically effective doses estimated under a genotoxic/linear (MA{sub G}) vs. a cytotoxic/nonlinear (MA{sub c}) mechanistic assumption for TCE-induced cancer. Increased risk conditional on effective dose was estimated under MA{sub G} based on seven rodent-bioassay data sets, and under MA{sub c} based on mouse hepatotoxicity data. Mean and upper-bound estimates of combined risk calculated by the unified approach were <10{sup -6} and 10{sup -4}, respectively, while corresponding estimates based on traditional deterministic methods were >10{sup -5} and 10{sup -4}, respectively. It was estimated that no TCE-related harm is likely to occur due to any plausible residential exposure scenario involving the site. The systematic probabilistic framework illustrated is particularly suited to characterizing risks that involve uncertain and/or diverse mechanisms of action.

  11. Integrated time-lapse and single-cell transcription studies highlight the variable and dynamic nature of human hematopoietic cell fate commitment

    PubMed Central

    Moussy, Alice; Cosette, Jérémie; Parmentier, Romuald; da Silva, Cindy; Corre, Guillaume; Richard, Angélique; Gandrillon, Olivier; Stockholm, Daniel

    2017-01-01

    Individual cells take lineage commitment decisions in a way that is not necessarily uniform. We address this issue by characterising transcriptional changes in cord blood-derived CD34+ cells at the single-cell level and integrating data with cell division history and morphological changes determined by time-lapse microscopy. We show that major transcriptional changes leading to a multilineage-primed gene expression state occur very rapidly during the first cell cycle. One of the 2 stable lineage-primed patterns emerges gradually in each cell with variable timing. Some cells reach a stable morphology and molecular phenotype by the end of the first cell cycle and transmit it clonally. Others fluctuate between the 2 phenotypes over several cell cycles. Our analysis highlights the dynamic nature and variable timing of cell fate commitment in hematopoietic cells, links the gene expression pattern to cell morphology, and identifies a new category of cells with fluctuating phenotypic characteristics, demonstrating the complexity of the fate decision process (which is different from a simple binary switch between 2 options, as it is usually envisioned). PMID:28749943

  12. Reducing the risk of rear-end collisions with infrastructure-to-vehicle (I2V) integration of variable speed limit control and adaptive cruise control system.

    PubMed

    Li, Ye; Wang, Hao; Wang, Wei; Liu, Shanwen; Xiang, Yun

    2016-08-17

    Adaptive cruise control (ACC) has been investigated recently to explore ways to increase traffic capacity, stabilize traffic flow, and improve traffic safety. However, researchers seldom have studied the integration of ACC and roadside control methods such as the variable speed limit (VSL) to improve safety. The primary objective of this study was to develop an infrastructure-to-vehicle (I2V) integrated system that incorporated both ACC and VSL to reduce rear-end collision risks on freeways. The intelligent driver model was firstly modified to simulate ACC behavior and then the VSL strategy used in this article was introduced. Next, the I2V system was proposed to integrate the 2 advanced techniques, ACC and VSL. Four scenarios of no control, VSL only, ACC only, and the I2V system were tested in simulation experiments. Time exposed time to collision (TET) and time integrated time to collision (TIT), 2 surrogate safety measures derived from time to collision (TTC), were used to evaluate safety issues associated with rear-end collisions. The total travel times of each scenario were also compared. The simulation results indicated that both the VSL-only and ACC-only methods had a positive impact on reducing the TET and TIT values (reduced by 53.0 and 58.6% and 59.0 and 65.3%, respectively). The I2V system combined the advantages of both ACC and VSL to achieve the most safety benefits (reduced by 71.5 and 77.3%, respectively). Sensitivity analysis of the TTC threshold also showed that the I2V system obtained the largest safety benefits with all of the TTC threshold values. The impact of different market penetration rates of ACC vehicles in I2V system indicated that safety benefits increase with an increase in ACC proportions. Compared to VSL-only and ACC-only scenarios, this integrated I2V system is more effective in reducing rear-end collision risks. The findings of this study provide useful information for traffic agencies to implement novel techniques to improve

  13. The comparison of the estimation of enzyme kinetic parameters by fitting reaction curve to the integrated Michaelis-Menten rate equations of different predictor variables.

    PubMed

    Liao, Fei; Zhu, Xiao-Yun; Wang, Yong-Mei; Zuo, Yu-Ping

    2005-01-31

    The estimation of enzyme kinetic parameters by nonlinear fitting reaction curve to the integrated Michaelis-Menten rate equation ln(S(0)/S)+(S(0)-S)/K(m)=(V(m)/K(m))xt was investigated and compared to that by fitting to (S(0)-S)/t=V(m)-K(m)x[ln(S(0)/S)/t] (Atkins GL, Nimmo IA. The reliability of Michaelis-Menten constants and maximum velocities estimated by using the integrated Michaelis-Menten equation. Biochem J 1973;135:779-84) with uricase as the model. Uricase reaction curve was simulated with random absorbance error of 0.001 at 0.075 mmol/l uric acid. Experimental reaction curve was monitored by absorbance at 293 nm. For both CV and deviation <20% by simulation, K(m) from 5 to 100 micromol/l was estimated with Eq. (1) while K(m) from 5 to 50 micromol/l was estimated with Eq. (2). The background absorbance and the error in the lag time of steady-state reaction resulted in negative K(m) with Eq. (2), but did not affect K(m) estimated with Eq. (1). Both equations gave better estimation of V(m). The computation time and the goodness of fit with Eq. (1) were 40-fold greater than those with Eq. (2). By experimentation, Eq. (1) yielded K(m) consistent with the Lineweaver-Burk plot analysis, but Eq. (2) gave many negative parameters. Apparent K(m) by Eq. (1) linearly increased, while V(m) were constant, vs. xanthine concentrations, and the inhibition constant was consistent with the Lineweaver-Burk plot analysis. These results suggested that the integrated rate equation that uses the predictor variable of reaction time was reliable for the estimation of enzyme kinetic parameters and applicable for the characterization of enzyme inhibitors.

  14. Multimodal integration of EEG and MEG data: a simulation study with variable signal-to-noise ratio and number of sensors.

    PubMed

    Babiloni, Fabio; Babiloni, Claudio; Carducci, Filippo; Romani, Gian Luca; Rossini, Paolo M; Angelone, Leonardo M; Cincotti, Febo

    2004-05-01

    Previous simulation studies have stressed the importance of the multimodal integration of electroencephalography (EEG) and magnetoencephalography (MEG) data in the estimation of cortical current density. In such studies, no systematic variations of the signal-to-noise ratio (SNR) and of the number of sensors were explicitly taken into account in the estimation process. We investigated effects of variable SNR and number of sensors on the accuracy of current density estimate by using multimodal EEG and MEG data. This was done by using as the dependent variable both the correlation coefficient (CC) and the relative error (RE) between imposed and estimated waveforms at the level of cortical region of interests (ROI). A realistic head and cortical surface model was used. Factors used in the simulations were: (1). the SNR of the simulated scalp data (with seven levels: infinite, 30, 20, 10, 5, 3, 1); (2). the particular inverse operator used to estimate the cortical source activity from the simulated scalp data (INVERSE, with two levels, including minimum norm and weighted minimum norm); and (3). the number of EEG or MEG sensors employed in the analysis (SENSORS, with three levels: 128, 61, 29 for EEG and 153, 61, or 38 in MEG). Analysis of variance demonstrated that all the considered factors significantly affect the CC and the RE indexes. Combined EEG-MEG data produced statistically significant lower RE and higher CC in source current density reconstructions compared to that estimated by the EEG and MEG data considered separately. These observations hold for the range of SNR values presented by the analyzed data. The superiority of current density estimation by multimodal integration of EEG and MEG was not due to differences in number of sensors between unimodal (EEG, MEG) and combined (EEG-MEG) inverse estimates. In fact, the current density estimate relative to the EEG-MEG multimodal integration involved 61 EEG plus 63 MEG sensors, whereas estimations carried out

  15. An integrated quality by design and mixture-process variable approach in the development of a capillary electrophoresis method for the analysis of almotriptan and its impurities.

    PubMed

    Orlandini, S; Pasquini, B; Stocchero, M; Pinzauti, S; Furlanetto, S

    2014-04-25

    The development of a capillary electrophoresis (CE) method for the assay of almotriptan (ALM) and its main impurities using an integrated Quality by Design and mixture-process variable (MPV) approach is described. A scouting phase was initially carried out by evaluating different CE operative modes, including the addition of pseudostationary phases and additives to the background electrolyte, in order to approach the analytical target profile. This step made it possible to select normal polarity microemulsion electrokinetic chromatography (MEEKC) as operative mode, which allowed a good selectivity to be achieved in a low analysis time. On the basis of a general Ishikawa diagram for MEEKC methods, a screening asymmetric matrix was applied in order to screen the effects of the process variables (PVs) voltage, temperature, buffer concentration and buffer pH, on critical quality attributes (CQAs), represented by critical separation values and analysis time. A response surface study was then carried out considering all the critical process parameters, including both the PVs and the mixture components (MCs) of the microemulsion (borate buffer, n-heptane as oil, sodium dodecyl sulphate/n-butanol as surfactant/cosurfactant). The values of PVs and MCs were simultaneously changed in a MPV study, making it possible to find significant interaction effects. The design space (DS) was defined as the multidimensional combination of PVs and MCs where the probability for the different considered CQAs to be acceptable was higher than a quality level π=90%. DS was identified by risk of failure maps, which were drawn on the basis of Monte-Carlo simulations, and verification points spanning the design space were tested. Robustness testing of the method, performed by a D-optimal design, and system suitability criteria allowed a control strategy to be designed. The optimized method was validated following ICH Guideline Q2(R1) and was applied to a real sample of ALM coated tablets.

  16. Mitochondrial-bacterial hybrids of BamA/Tob55 suggest variable requirements for the membrane integration of β-barrel proteins

    PubMed Central

    Pfitzner, Anna-Katharina; Steblau, Nadja; Ulrich, Thomas; Oberhettinger, Philipp; Autenrieth, Ingo B.; Schütz, Monika; Rapaport, Doron

    2016-01-01

    β-Barrel proteins are found in the outer membrane (OM) of Gram-negative bacteria, chloroplasts and mitochondria. The assembly of these proteins into the corresponding OM is facilitated by a dedicated protein complex that contains a central conserved β-barrel protein termed BamA in bacteria and Tob55/Sam50 in mitochondria. BamA and Tob55 consist of a membrane-integral C-terminal domain that forms a β-barrel pore and a soluble N-terminal portion comprised of one (in Tob55) or five (in BamA) polypeptide transport-associated (POTRA) domains. Currently the functional significance of this difference and whether the homology between BamA and Tob55 can allow them to replace each other are unclear. To address these issues we constructed hybrid Tob55/BamA proteins with differently configured N-terminal POTRA domains. We observed that constructs harboring a heterologous C-terminal domain could not functionally replace the bacterial BamA or the mitochondrial Tob55 demonstrating species-specific requirements. Interestingly, the various hybrid proteins in combination with the bacterial chaperones Skp or SurA supported to a variable extent the assembly of bacterial β-barrel proteins into the mitochondrial OM. Collectively, our findings suggest that the membrane assembly of various β-barrel proteins depends to a different extent on POTRA domains and periplasmic chaperones. PMID:27982054

  17. The integral pulse frequency modulation model with time-varying threshold: application to heart rate variability analysis during exercise stress testing.

    PubMed

    Bailón, Raquel; Laouini, Ghailen; Grao, César; Orini, Michele; Laguna, Pablo; Meste, Olivier

    2011-03-01

    In this paper, an approach for heart rate variability analysis during exercise stress testing is proposed based on the integral pulse frequency modulation (IPFM) model, where a time-varying threshold is included to account for the nonstationary mean heart rate. The proposed technique allows the estimation of the autonomic nervous system (ANS) modulating signal using the methods derived for the IPFM model with constant threshold plus a correction, which is shown to be needed to take into account the time-varying mean heart rate. On simulations, this technique allows the estimation of the ANS modulation on the heart from the beat occurrence time series with lower errors than the IPFM model with constant threshold (1.1% ± 1.3% versus 15.0% ± 14.9%). On an exercise stress testing database, the ANS modulation estimated by the proposed technique is closer to physiology than that obtained from the IPFM model with constant threshold, which tends to overestimate the ANS modulation during the recovery and underestimate it during the initial rest.

  18. Current climate variability as a guide to the `new normal': exploring multiyear climate warming impacts in the San Joaquin River basin using an integrated hydrologic model

    NASA Astrophysics Data System (ADS)

    Gilbert, J. M.; Maxwell, R. M.

    2016-12-01

    As with many catchments in the mountain west, water resources in the San Joaquin River basin are vulnerable to a warming climate through diminished snowpack and increased evaporative demand. The impact of warming is not necessarily uniform over a complex landscape, such as that formed by the Sierra Nevada Mountains and the Central Valley, nor is it constant across a typical range of wet and dry years. To address this spatial and temporal variability, we simulate the terrestrial hydrology of a 5-year wet-dry cycle in the San Joaquin River basin under baseline (no warming), uniform 2°C warming, and uniform 4°C warming scenarios using the ParFlow-CLM integrated hydrologic platform. The precipitation timing, amount, and spatial patterns are identical across each scenario. At the basin scale, incremental warming partitions more precipitation into evapotranspiration (ET) and away from runoff, although the larger change in partitioning occurs between the baseline and 2°C warming compared to the 2°C and 4°C warming. In general, the year-to-year variation in precipitation has a bigger effect on runoff, ET, and recharge than the climate perturbations although the impact of warming for a given year suggests that the recent drought may be a good analogy for an average future climate year. Specifically, impacts from the 4°C warming simulation reduce streamflow volume to a level associated with the current-climate dry years. Additional analysis of spatial and temporal properties of changes in runoff, ET, and subsurface storage suggest this aggregate pattern is the consequence of a complex combination of behaviors and feedbacks within the system.

  19. The Mean and the Individual: Integrating Variable-Centered and Person-Centered Analyses of Cognitive Recovery in Patients with Substance Use Disorders

    PubMed Central

    Bates, Marsha E.; Buckman, Jennifer F.; Voelbel, Gerald T.; Eddie, David; Freeman, Jason

    2013-01-01

    Neuropsychological and cognitive deficits are observed in the majority of persons with alcohol and drug use disorders and may interfere with treatment processes and outcomes. Although, on average, the brain and cognition improve with abstinence or markedly reduced substance use, better understanding of the heterogeneity in the time-course and extent of cognitive recovery at the individual level is useful to promote bench-to-bedside translation and inform clinical decision making. This study integrated a variable-centered and a person-centered approach to characterize diversity in cognitive recovery in 197 patients in treatment for a substance use disorder. We assessed executive function, verbal ability, memory, and complex information processing speed at treatment entry, and then 6, 26, and 52 weeks later. Structural equation modeling was used to define underlying ability constructs and determine the mean level of cognitive changes in the sample while minimizing measurement error and practice effects on specific tests. Individual-level empirical growth plots of latent factor scores were used to explore prototypical trajectories of cognitive change. At the level of the mean, small to medium effect size gains in cognitive abilities were observed over 1 year. At the level of the individual, the mean trajectory of change was also the modal individual recovery trajectory shown by about half the sample. Other prototypical cognitive change trajectories observed in all four cognitive domains included Delayed Gain, Loss of Gain, and Continuous Gain. Together these trajectories encompassed between 86 and 94% of individual growth plots across the four latent abilities. Further research is needed to replicate and predict trajectory membership. Replication of the present findings would have useful implications for targeted treatment planning and the new cognitive interventions being developed to enhance treatment outcomes. PMID:24399976

  20. Regional heavy metal pollution in crops by integrating physiological function variability with spatio-temporal stability using multi-temporal thermal remote sensing

    NASA Astrophysics Data System (ADS)

    Liu, Meiling; Liu, Xiangnan; Zhang, Biyao; Ding, Chao

    2016-09-01

    Heavy metal stress in crops is characterized by stability in space and time, which differs from other stressors that are typically more transient (e.g., drought, pests/diseases, and mismanagement). The objective of this study is to assess regional heavy metal stress in rice by integrating physiological function variability with spatio-temporal stability based on multi-temporal thermal infrared (TIR) remote sensing images. The field in which the experiment was conducted is located in Zhuzhou City, Hunan Province, China. HJ-1B images and in-situ measured data were collected from rice growing in heavy metal contaminated soils. A stress index (SI) was devised as an indicator for the degree of heavy metal stress of the rice in different growth stages, and a time-spectrum feature space (TSFS) model was used to determine rice heavy metal stress levels. The results indicate that (i) SI is a good indicator of rice damage caused by heavy metal stress. Minimum values of SI occur in rice subject to high pollution, followed by larger SI with medium pollution and maximum SI for low pollution, for the same growth stage. (ii) SI shows some variation for different growth stages of rice, and the minimum SI occurs at the flowering stage. (iii) The TSFS model is successful at identifying rice heavy metal stress, and stress levels in rice stabilized regardless of the model being applied in the two different years. This study suggests that regional heavy metal stress in crops can be accurately detected using TIR technology, if a sensitive indicator of crop physiological function impairment is used and an effective model is selected. A combination of spectrum and spatio-temporal information appears to be a very promising method for monitoring crops with various stressors.

  1. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean): an integrative analysis of spatial variability and biophysical forcings

    NASA Astrophysics Data System (ADS)

    Forest, A.; Babin, M.; Stemmann, L.; Picheral, M.; Sampei, M.; Fortier, L.; Gratton, Y.; Bélanger, S.; Devred, E.; Sahlin, J.; Doxaran, D.; Joux, F.; Ortega-Retuerta, E.; Martín, J.; Jeffrey, W. H.; Gasser, B.; Miquel, J. Carlos

    2013-05-01

    A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here we combine mooring times series, ship-based measurements and remote sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC) across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their determinants in summer. Flux data were obtained with sediment traps moored around 125 m and via a regional empirical algorithm applied to particle size distributions (17 classes from 0.08-4.2 mm) measured by an Underwater Vision Profiler 5. The low fractal dimension (i.e., porous, fluffy particles) derived from the algorithm (1.26 ± 0.34) and the dominance (~ 77%) of rapidly sinking small aggregates (< 0.5 mm) in total fluxes suggested that settling material was the product of recent aggregation processes between marine detritus, gel-like substances, and ballast minerals. Modeled settling velocity of small and large aggregates was, respectively, higher and lower than in previous studies within which a high fractal dimension (i.e., more compact particles) was consequential of deep-trap collection (~400-1300 m). Redundancy analyses and forward selection of abiotic/biotic parameters, linear trends, and spatial structures (i.e., principal coordinates of neighbor matrices, PCNM) were conducted to partition the variation of the 17 POC flux size classes. Flux variability was explained at 69.5% by the addition of a temporal trend, 7 significant PCNM, and 9 biophysical variables. The first PCNM canonical axis (44.5% of spatial variance) reflected the total magnitude of POC fluxes through a shelf-basin gradient controlled by bottom depth and sea ice concentration (p < 0.01). The second most important spatial structure (5.0%) corresponded to areas where shelf break upwelling is known to occur under easterlies and where phytoplankton was

  2. Evaluating the role of soil variability on groundwater pollution and recharge at regional scale by integrating a process-based vadose zone model in a stochastic approach

    NASA Astrophysics Data System (ADS)

    Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna; Lamaddalena, Nicola; Zdruli, Pandi

    2013-04-01

    Interpreting and predicting the evolution of water resources and soils at regional scale are continuing challenges for natural scientists. Examples include non-point source (NPS) pollution of soil and surface and subsurface water from agricultural chemicals and pathogens, as well as overexploitation of groundwater resources. The presence and build up of NPS pollutants may be harmful for both soil and groundwater resources. The accumulation of salts and trace elements in soils can significantly impact crop productivity, while loading of salts, nitrates, trace elements and pesticides into groundwater supplies can deteriorate a source of drinking and irrigation water. Consequently, predicting the spatial distribution and fate of NPS pollutants in soils at applicative scales is now considered crucial for maintaining the fragile balance between crop productivity and the negative environmental impacts of NPS pollutants, which is a basis of sustainable agriculture. Soil scientists and hydrologists are regularly asked to assist state agencies to understand these critical environmental issues. The most frequent inquiries are related to the development of mathematical models needed for analyzing the impacts of alternative land-use and best management use and management of soil and water resources. Different modelling solutions exist, mainly differing on the role of the vadose zone and its horizontal and vertical variability in the predictive models. The vadose zone (the region from the soil surface to the groundwater surface) is a complex physical, chemical and biological ecosystem that controls the passage of NPS pollutants from the soil surface where they have been deposited or accumulated due to agricultural activities, to groundwater. Physically based distributed hydrological models require the internal variability of the vadose zone be explored at a variety of scales. The equations describing fluxes and storage of water and solutes in the unsaturated zone used in these

  3. Integrating the EMPD with an Alpine altitudinal training set to reconstruct climate variables in Holocene pollen records from high-altitude peat bogs

    NASA Astrophysics Data System (ADS)

    Furlanetto, Giulia; Badino, Federica; Brunetti, Michele; Champvillair, Elena; De Amicis, Mattia; Maggi, Valter; Pini, Roberta; Ravazzi, Cesare; Vallé, Francesca

    2016-04-01

    Temperatures and precipitation are the main environmental factors influencing vegetation and pollen production. Knowing the modern climate optima and tolerances of those plants represented in fossil assemblages and assuming that the relationships between plants and climate in the past are not dissimilar from the modern ones, fossil pollen records offer many descriptors to reconstruct past climate variables. The aim of our work is to investigate the potential of high-altitude pollen records from an Alpine peat bog (TBValter, close to the Ruitor Glacier, Western Italian Alps) for quantitative paleoclimate estimates. The idea behind is that high-altitude ecosystems are more sensitive to climate changes, especially to changes in July temperatures that severely affect the timberline ecotone. Meantime, we met with difficulties when considering the factors involved in pollen dispersal over a complex altitudinal mountain pattern, such as the Alps. We used the EMPD-European Modern Pollen Database (Davis et al., 2013) as modern training set to be compared with our high-altitude fossil site. The EMPD dataset is valuable in that it provides a large geographic coverage of main ecological and climate gradients (at sub-continental scale) but lacks in sampling of altitudinal gradients and high-altitude sites in the Alps. We therefore designed an independent altitudinal training set for the alpine valley hosting our fossil site. 27 sampling plots were selected along a 1700m-elevational transect. In a first step, each plot was provided with (i) 3 moss polsters collected following the guidelines provided by Cañellas-Boltà et al. (2009) and analyzed separately to account for differences in pollen deposition at small scale, (ii) morphometrical parameters obtained through a high-resolution DEM, and (iii) temperature and precipitation were estimated by means of weighted linear regression of the meteorological variable versus elevation, locally evaluated for each site (Brunetti et al

  4. Spatial and temporal variability of column-integrated CO2: identifying drivers and variations from high-resolution model simulations and OCO-2 observations

    NASA Astrophysics Data System (ADS)

    Chatterjee, A.; Ott, L.; Wennberg, P. O.; Kawa, S. R.; O'Dell, C.; Osterman, G. B.; Wunch, D.

    2015-12-01

    Isolating the drivers and variations in column-averaged dry air mole fraction of carbon dioxide (XCO2) is essential for mining information from space-based remote-sensing observations, such as those available from the Orbiting Carbon Observatory-2 (OCO-2). Contrary to the large number of studies analyzing the variability of surface CO2 concentrations, studies analyzing the spatiotemporal variability of XCO2 are relatively limited. More importantly, these results are either based on a sparse network of ground-based total column observations (i.e., from the Total Column Carbon Observing Network - TCCON) or derived from low-resolution model simulations. In this study, using the high-resolution (~7 km) GEOS-5 model simulated fields and the high-density observations from OCO-2, we investigate how variability in surface fluxes and/or meteorological drivers impact the observed XCO2 variability across a range of scales. The study focuses on ~13:30 LT and is designed to highlight the significant contributors to local and regional scale XCO2 variability from daily to seasonal timescales. In collaboration with the OCO-2 Validation team, the variability information is also being used to identify small geographical areas (<1° or ~100km) where the XCO2 is expected to be relatively constant. These small areas then serve as target regions for examining the potential of external variables (for e.g., surface reflectance, aerosol) to generate biases (variability) in the XCO2 retrievals in those regions. We will also show comparison results of the model-based variability analyses with the variability statistics derived from actual OCO-2 retrievals. This comparison serves as an important consistency check for the simulated fields from the GEOS-5 model. Finally, we will review these results in terms of assessing and quantifying representation errors as well as developing and implementing data thinning/'superobbing' algorithms for OCO-2 retrievals.

  5. Predicting the Persistence of Full-Time African-American Students Attending 4-Year Public Colleges: A Disaggregation of Financial Aid Packaging and Social and Academic Integration Variables

    ERIC Educational Resources Information Center

    Smith, Curt L.

    2010-01-01

    The purpose of the study was to investigate to what extent do demographic characteristics, high school experience, aspirations and achievement, college experience-academic integration, college experience-social integration, financial aid, and price influence the first-year persistence of African-American students attending 4-year public colleges.…

  6. MODFLOW-2000, the U.S. Geological Survey Modular Ground-Water Model--Documentation of the SEAWAT-2000 Version with the Variable-Density Flow Process (VDF) and the Integrated MT3DMS Transport Process (IMT)

    USGS Publications Warehouse

    Langevin, Christian D.; Shoemaker, W. Barclay; Guo, Weixing

    2003-01-01

    SEAWAT-2000 is the latest release of the SEAWAT computer program for simulation of three-dimensional, variable-density, transient ground-water flow in porous media. SEAWAT-2000 was designed by combining a modified version of MODFLOW-2000 and MT3DMS into a single computer program. The code was developed using the MODFLOW-2000 concept of a process, which is defined as ?part of the code that solves a fundamental equation by a specified numerical method.? SEAWAT-2000 contains all of the processes distributed with MODFLOW-2000 and also includes the Variable-Density Flow Process (as an alternative to the constant-density Ground-Water Flow Process) and the Integrated MT3DMS Transport Process. Processes may be active or inactive, depending on simulation objectives; however, not all processes are compatible. For example, the Sensitivity and Parameter Estimation Processes are not compatible with the Variable-Density Flow and Integrated MT3DMS Transport Processes. The SEAWAT-2000 computer code was tested with the common variable-density benchmark problems and also with problems representing evaporation from a salt lake and rotation of immiscible fluids.

  7. Holocene climate variability in Texas, USA: An integration of existing paleoclimate data and modeling with a new, high-resolution speleothem record

    USGS Publications Warehouse

    Wong, Corinne I.; Banner, Jay L.; Musgrove, MaryLynn

    2015-01-01

    Delineating the climate processes governing precipitation variability in drought-prone Texas is critical for predicting and mitigating climate change effects, and requires the reconstruction of past climate beyond the instrumental record. We synthesize existing paleoclimate proxy data and climate simulations to provide an overview of climate variability in Texas during the Holocene. Conditions became progressively warmer and drier transitioning from the early to mid Holocene, culminating between 7 and 3 ka (thousand years ago), and were more variable during the late Holocene. The timing and relative magnitude of Holocene climate variability, however, is poorly constrained owing to considerable variability among the different records. To help address this, we present a new speleothem (NBJ) reconstruction from a central Texas cave that comprises the highest resolution proxy record to date, spanning the mid to late Holocene. NBJ trace-element concentrations indicate variable moisture conditions with no clear temporal trend. There is a decoupling between NBJ growth rate, trace-element concentrations, and δ18O values, which indicate that (i) the often direct relation between speleothem growth rate and moisture availability is likely complicated by changes in the overlying ecosystem that affect subsurface CO2 production, and (ii) speleothem δ18O variations likely reflect changes in moisture source (i.e., proportion of Pacific-vs. Gulf of Mexico-derived moisture) that appear not to be linked to moisture amount.

  8. Examining Academic Variables Affecting the Persistence and Attainment of Black Male Collegians: A Focus on Academic Performance and Integration in the Two-Year College

    ERIC Educational Resources Information Center

    Wood, J. Luke

    2014-01-01

    The purpose of this study was to investigate the effect of academic variables (e.g., grade point average, major change, informal meetings with faculty) on six year persistence and attainment among black male students in community colleges. Data was collected from the Beginning Postsecondary Students Longitudinal Study and was analyzed using…

  9. Examining the integrity of measurement of cognitive abilities in the prediction of achievement: Comparisons and contrasts across variables from higher-order and bifactor models.

    PubMed

    Benson, Nicholas F; Kranzler, John H; Floyd, Randy G

    2016-10-01

    Prior research examining cognitive ability and academic achievement relations have been based on different theoretical models, have employed both latent variables as well as observed variables, and have used a variety of analytic methods. Not surprisingly, results have been inconsistent across studies. The aims of this study were to (a) examine how relations between psychometric g, Cattell-Horn-Carroll (CHC) broad abilities, and academic achievement differ across higher-order and bifactor models; (b) examine how well various types of observed scores corresponded with latent variables; and (c) compare two types of observed scores (i.e., refined and non-refined factor scores) as predictors of academic achievement. Results suggest that cognitive-achievement relations vary across theoretical models and that both types of factor scores tend to correspond well with the models on which they are based. However, orthogonal refined factor scores (derived from a bifactor model) have the advantage of controlling for multicollinearity arising from the measurement of psychometric g across all measures of cognitive abilities. Results indicate that the refined factor scores provide more precise representations of their targeted constructs than non-refined factor scores and maintain close correspondence with the cognitive-achievement relations observed for latent variables. Thus, we argue that orthogonal refined factor scores provide more accurate representations of the relations between CHC broad abilities and achievement outcomes than non-refined scores do. Further, the use of refined factor scores addresses calls for the application of scores based on latent variable models. Copyright © 2016 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  10. Predictors of Academic Performance and School Engagement--Integrating Persistence, Motivation and Study Skills Perspectives Using Person-Centered and Variable-Centered Approaches

    ERIC Educational Resources Information Center

    Moreira, Paulo A. S.; Dias, Paulo; Vaz, Filipa Machado; Vaz, Joao Machado

    2013-01-01

    There is a growing need for the integration of various theoretical perspectives on academic performance, especially the theories on educational persistence, and motivational theories. Recent models of students' engagement with school incorporate different dimensions of students, family and school. However, some authors are arguing that academic…

  11. Predictors of Academic Performance and School Engagement--Integrating Persistence, Motivation and Study Skills Perspectives Using Person-Centered and Variable-Centered Approaches

    ERIC Educational Resources Information Center

    Moreira, Paulo A. S.; Dias, Paulo; Vaz, Filipa Machado; Vaz, Joao Machado

    2013-01-01

    There is a growing need for the integration of various theoretical perspectives on academic performance, especially the theories on educational persistence, and motivational theories. Recent models of students' engagement with school incorporate different dimensions of students, family and school. However, some authors are arguing that academic…

  12. Methods for Addressing Uncertainty and Variability to Characterize Potential Health Risk From Trichloroethylene-Contaminated Ground Water Beale Air Force Base in California: Integration of Uncertainty and Variability in Pharmacokinetics and Dose-Response

    SciTech Connect

    Bogen, K.T.

    1999-09-29

    Traditional estimates of health risk are typically inflated, particularly if cancer is the dominant endpoint and there is fundamental uncertainty as to mechanism(s) of action. Risk is more realistically characterized if it accounts for joint uncertainty and interindividual variability after applying a unified probabilistic approach to the distributed parameters of all (linear as well as nonlinear) risk-extrapolation models involved. Such an approach was applied to characterize risks to potential future residents posed by trichloroethylene (TCE) in ground water at an inactive landfill site on Beale Air Force Base in California. Variability and uncertainty were addressed in exposure-route-specific estimates of applied dose, in pharmacokinetically based estimates of route-specific metabolized fractions of absorbed TCE, and in corresponding biologically effective doses estimated under a genotoxic/linear (MA{sub g}) vs. a cytotoxic/nonlinear (MA{sub c}) mechanistic assumption for TCE-induced cancer. Increased risk conditional on effective dose was estimated under MA{sub G} based on seven rodent-bioassay data sets, and under MA, based on mouse hepatotoxicity data. Mean and upper-bound estimates of combined risk calculated by the unified approach were <10{sup -6} and <10{sup -4}, respectively, while corresponding estimates based on traditional deterministic methods were >10{sup -5} and >10{sup -4}, respectively. It was estimated that no TCE-related harm is likely occur due any plausible residential exposure scenario involving the site. The unified approach illustrated is particularly suited to characterizing risks that involve uncertain and/or diverse mechanisms of action.

  13. Integrating inter- and intra-annual tree-ring width, carbon isotopes and anatomy: responses to climate variability in a temperate oak forest

    NASA Astrophysics Data System (ADS)

    Granda, Elena; Bazot, Stéphane; Fresneau, Chantal; Boura, Anaïs; Faccioni, Georgia; Damesin, Claire

    2015-04-01

    While many forests are experiencing strong tree declines due to climate change in temperate ecosystems, others nearby to those declining show no apparent signs of decline. This could be due to particular microsite conditions or, for instance, to a higher plasticity of given traits that allow a better performance under stressful conditions. We studied oak functional mechanisms (Quercus petraea) leading to the apparently healthy status of the forest and their relation to the observed climatic variability. This study was conducted in the Barbeau Forest (northern France), where cores from mature trees were collected. Three types of functional traits (secondary growth, physiological variables - δ13C and derived Δ13C and iWUE- and several anatomical ones -e.g. vessel area, density-) were recorded for each ring for the 1991-2011 period, distinguishing EW from LW in all measured traits. Among the three types of functional traits, those related to growth experienced the highest variability both between years and between individuals, followed by anatomical and physiological ones. Secondary growth maintained a constant trend during the study period. Instead, ring, EW and LW δ13C slightly declined from 1991 to 2011. Additional intra-ring δ13C analyses allowed for a more detailed understanding of the seasonal dynamics within each year. In particular, the year 2007 (an especially favorable climatic year during the growing season) showed the lowest δ13C values during the EW-LW transition for the whole study period. Inter-annual anatomical traits varied in their responses, but in general, no temporal trends were found. The results from structural equation modeling (SEM) showed direct relationships of seasonal climate and growth, as well as indirect relationships mediated by anatomical and physiological traits. We further discuss the implications of these results on future forest responses to ongoing climate changes.

  14. Pilot test results comparing the All Stars program with seventh grade D.A.R.E.: program integrity and mediating variable analysis.

    PubMed

    Hansen, W B

    1996-08-01

    A pilot test of a new program, All Stars, was completed. Four variables known from prior research to mediate high-risk behaviors were measured: 1) personal commitment to avoid participating in high-risk behaviors, 2) ideals incongruent with high-risk behaviors, 3) bonding with prosocial institutions, and 4) conventional beliefs about social norms regarding high-risk behaviors. Compared to students who received the seventh grade D.A.R.E. program, students' who received the All Stars program had significantly better outcomes on each mediator. All Stars students also gave superior ratings to the program and their involvement in it.

  15. Composition and chemical variability of the leaf oil from Corsican Juniperus thurifera. Integrated analysis by GC(RI), GC-MS and 13C NMR.

    PubMed

    Ottavioli, Josephine; Casanova, Joseph; Bighelli, Ange

    2010-12-01

    The composition of 16 samples of leaf oil from Corsican Juniperus thurifera was investigated by integrated techniques, GC, GC-MS and 13C NMR. K-means partitioning and PCA analysis of the data allowed the definition of a main group (14 samples) dominated by limonene (mean = 52.2%, SD = 6.4) and alpha-pinene (mean = 7.2%, SD = 3.8). Limonene and beta-elemol (up to 19.7%) were identified as the major components of two atypic samples.

  16. Effects of an Obesity Intervention Integrating Physical Activity and Psychological Strategy on BMI, Physical Activity, and Psychological Variables in Male Obese Adolescents.

    PubMed

    Lee, HakGweon; Kim, YoungHo

    2015-01-01

    The current study investigated the effect of an obesity intervention incorporating physical activity and behavior-based motivational enhancement intervention on BMI, physical activity levels, and psychological variables toward physical activity in male obese adolescents. Single group study without having a control group was carried out in Korea. Sixty-eight obese male adolescents who had BMI greater than 25 kg/m(2) participated in the 16-week obesity intervention. During this period, the study participants' BMI, physical activity levels, self-efficacy, and perceived benefits and barriers were measured at the three time point (baseline, after week 8, and after week 16). Results indicated that obese adolescents' BMI significantly decreased (F = 3.51, p = .03) and physical activity (F = 4.01, p = .02) significantly increased over the 16-week obesity intervention. In addition, Exercise self-efficacy (F = 5.02) and perceived benefits toward physical activity (F = 5.34) significantly increased but perceived barriers of physical activity (F = 5.10) gradually decreased over the intervention. This study suggests that an obesity intervention combining physical activity and behavior-based motivational enhancement intervention significantly contributed to decreased BMI, increased physical activity, and positively changed psychological variables related to physical activity. This first application has resulted in preliminary support for this intervention modality within non-western obese adolescents.

  17. The impact of integrating WorldView-2 sensor and environmental variables in estimating plantation forest species aboveground biomass and carbon stocks in uMgeni Catchment, South Africa

    NASA Astrophysics Data System (ADS)

    Dube, Timothy; Mutanga, Onisimo

    2016-09-01

    Reliable and accurate mapping and extraction of key forest indicators of ecosystem development and health, such as aboveground biomass (AGB) and aboveground carbon stocks (AGCS) is critical in understanding forests contribution to the local, regional and global carbon cycle. This information is critical in assessing forest contribution towards ecosystem functioning and services, as well as their conservation status. This work aimed at assessing the applicability of the high resolution 8-band WorldView-2 multispectral dataset together with environmental variables in quantifying AGB and aboveground carbon stocks for three forest plantation species i.e. Eucalyptus dunii (ED), Eucalyptus grandis (EG) and Pinus taeda (PT) in uMgeni Catchment, South Africa. Specifically, the strength of the Worldview-2 sensor in terms of its improved imaging agilities is examined as an independent dataset and in conjunction with selected environmental variables. The results have demonstrated that the integration of high resolution 8-band Worldview-2 multispectral data with environmental variables provide improved AGB and AGCS estimates, when compared to the use of spectral data as an independent dataset. The use of integrated datasets yielded a high R2 value of 0.88 and RMSEs of 10.05 t ha-1 and 5.03 t C ha-1 for E. dunii AGB and carbon stocks; whereas the use of spectral data as an independent dataset yielded slightly weaker results, producing an R2 value of 0.73 and an RMSE of 18.57 t ha-1 and 09.29 t C ha-1. Similarly, high accurate results (R2 value of 0.73 and RMSE values of 27.30 t ha-1 and 13.65 t C ha-1) were observed from the estimation of inter-species AGB and carbon stocks. Overall, the findings of this work have shown that the integration of new generation multispectral datasets with environmental variables provide a robust toolset required for the accurate and reliable retrieval of forest aboveground biomass and carbon stocks in densely forested terrestrial ecosystems.

  18. Intra-population variability of ocean acidification impacts on the physiology of Baltic blue mussels (Mytilus edulis): integrating tissue and organism response.

    PubMed

    Stapp, L S; Thomsen, J; Schade, H; Bock, C; Melzner, F; Pörtner, H O; Lannig, G

    2016-12-05

    Increased maintenance costs at cellular, and consequently organism level, are thought to be involved in shaping the sensitivity of marine calcifiers to ocean acidification (OA). Yet, knowledge of the capacity of marine calcifiers to undergo metabolic adaptation is sparse. In Kiel Fjord, blue mussels thrive despite periodically high seawater PCO2, making this population interesting for studying metabolic adaptation under OA. Consequently, we conducted a multi-generation experiment and compared physiological responses of F1 mussels from 'tolerant' and 'sensitive' families exposed to OA for 1 year. Family classifications were based on larval survival; tolerant families settled at all PCO2 levels (700, 1120, 2400 µatm) while sensitive families did not settle at the highest PCO2 (≥99.8% mortality). We found similar filtration rates between family types at the control and intermediate PCO2 level. However, at 2400 µatm, filtration and metabolic scope of gill tissue decreased in tolerant families, indicating functional limitations at the tissue level. Routine metabolic rates (RMR) and summed tissue respiration (gill and outer mantle tissue) of tolerant families were increased at intermediate PCO2, indicating elevated cellular homeostatic costs in various tissues. By contrast, OA did not affect tissue and routine metabolism of sensitive families. However, tolerant mussels were characterised by lower RMR at control PCO2 than sensitive families, which had variable RMR. This might provide the energetic scope to cover increased energetic demands under OA, highlighting the importance of analysing intra-population variability. The mechanisms shaping such difference in RMR and scope, and thus species' adaptation potential, remain to be identified.

  19. Geographic variability in HIV and injection drug use in Ukraine: Implications for integration and expansion of drug treatment and HIV care

    PubMed Central

    Zaller, Nickolas; Mazhnaya, Alonya; Larney, Sarah; Islam, Zahed; Shost, Alyona; Prokhorova, Tatiana; Rybak, Natasha; Flanigan, Timothy

    2015-01-01

    Background Ukraine has the highest HIV burden of any European country with much of the current HIV epidemic concentrated among people who inject drugs (PWIDs) and their sexual partners. Opiate substitution therapy (OST) is limited in Ukraine and expansion of OST is urgently needed to help stem the tide of the HIV epidemic. Methods We accessed publicly available data in Ukraine in order to explore geographic variability with respect to prevalence of HIV, PWIDs and OST programmes. Results The regions of Ukraine with the largest number of opioid dependent persons (the south and eastern portions of the country) correspond to the regions with the highest HIV prevalence and HIV incidence. The number of opioid PWIDs per 100,000 population as well as the number of all OST treatment slots per 100,000 varied significantly across the three HIV prevalence categories. Overall, the proportion of individuals receiving either methadone maintenance therapy (MMT) or buprenorphine maintenance therapy (BMT) was quite low: average across categories: 7.3% and 0.4%, respectively. Additionally, less than half of OST patients receiving MMT or BMT were HIV positive patients. Conclusion There is significant geographic variability in both numbers of HIV positive individuals and numbers of PWIDs across Ukraine, however, there may be a more concentrated epidemic among PWIDs in many regions of the country. Scale up of addiction treatment for PWID, especially OST, can have a significant impact on preventing injection related morbidity, such as HIV and HCV infection. Ukraine can learn from the mistakes other nations have made in denying critical treatment opportunities to PWID. PMID:25304049

  20. Geographic variability in HIV and injection drug use in Ukraine: implications for integration and expansion of drug treatment and HIV care.

    PubMed

    Zaller, Nickolas; Mazhnaya, Alonya; Larney, Sarah; Islam, Zahed; Shost, Alyona; Prokhorova, Tatiana; Rybak, Natasha; Flanigan, Timothy

    2015-01-01

    Ukraine has the highest HIV burden of any European country with much of the current HIV epidemic concentrated among people who inject drugs (PWIDs) and their sexual partners. Opiate substitution therapy (OST) is limited in Ukraine and expansion of OST is urgently needed to help stem the tide of the HIV epidemic. We accessed publicly available data in Ukraine in order to explore geographic variability with respect to prevalence of HIV, PWIDs and OST programmes. The regions of Ukraine with the largest number of opioid dependent persons (the south and eastern portions of the country) correspond to the regions with the highest HIV prevalence and HIV incidence. The number of opioid PWIDs per 100,000 population as well as the number of all OST treatment slots per 100,000 varied significantly across the three HIV prevalence categories. Overall, the proportion of individuals receiving either methadone maintenance therapy (MMT) or buprenorphine maintenance therapy (BMT) was quite low: average across categories: 7.3% and 0.4%, respectively. Additionally, less than half of OST patients receiving MMT or BMT were HIV positive patients. There is significant geographic variability in both numbers of HIV positive individuals and numbers of PWIDs across Ukraine, however, there may be a more concentrated epidemic among PWIDs in many regions of the country. Scale up of addiction treatment for PWID, especially OST, can have a significant impact on preventing injection related morbidity, such as HIV and HCV infection. Ukraine can learn from the mistakes other nations have made in denying critical treatment opportunities to PWID. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Regional Hydroclimatic Impacts of Contemporary Amazonian Deforestation and Their Spatiotemporal Variability - An Integrated Study Using Remotely Sensed Data and Numerical Tools

    NASA Astrophysics Data System (ADS)

    Medvigy, D.; Khanna, J.

    2016-12-01

    The Amazon rainforest has been under deforestation for more than four decades. Recent investigation of the regional hydroclimatic impacts of the past three decades of deforestation has revealed a strong scale-dependence of the atmospheric response to land use change. Contemporary deforestation, affecting spatial scales of a few hundreds of kilometers, has resulted in a spatial redistribution of the local dry season rainfall, with downwind and upwind deforested regions receiving respectively 30% more and 30% less rainfall from the area mean. This phenomenon is attributable to a `dynamical' response of the boundary layer air to a reduction in surface roughness due to deforestation, apparent in both satellite and numerically simulated data. This response is starkly different from a spatially uniform increase in non-precipitating cloudiness triggered by small scale clearings, prevalent in the early phases of deforestation. This study investigates the `generalizability' of the dynamical mechanism to understand its impacts on a continually deforested Amazonia. In particular, we investigate the spatiotemporal variability of the dynamical mechanism. The nature of this investigation demands long time series and large spatial converge datasets of the hydroclimate. As such, satellite imagery of clouds (GridSat) and precipitation (PERSIANN and TRMM) has proven particularly useful in facilitating this analysis. The analysis is further complemented by a reanalysis product (ERA-interim) and numerical simulations (using a variable resolution GCM). Results indicate the presence of the dynamical mechanism during local dry and transition seasons effecting the mean precipitation during this period. Its effect on the transition season precipitation can be important for the local dry season length. The dynamical mechanism also occurs in atmospheric conditions which are otherwise less conducive to thermally triggered convection. Hence, this mechanism, which effects the seasons most

  2. An integrated approach based on uniform quantization for the evaluation of complexity of short-term heart period variability: Application to 24 h Holter recordings in healthy and heart failure humans

    NASA Astrophysics Data System (ADS)

    Porta, A.; Faes, L.; Masé, M.; D'Addio, G.; Pinna, G. D.; Maestri, R.; Montano, N.; Furlan, R.; Guzzetti, S.; Nollo, G.; Malliani, A.

    2007-03-01

    We propose an integrated approach based on uniform quantization over a small number of levels for the evaluation and characterization of complexity of a process. This approach integrates information-domain analysis based on entropy rate, local nonlinear prediction, and pattern classification based on symbolic analysis. Normalized and non-normalized indexes quantifying complexity over short data sequences (˜300 samples) are derived. This approach provides a rule for deciding the optimal length of the patterns that may be worth considering and some suggestions about possible strategies to group patterns into a smaller number of families. The approach is applied to 24h Holter recordings of heart period variability derived from 12 normal (NO) subjects and 13 heart failure (HF) patients. We found that: (i) in NO subjects the normalized indexes suggest a larger complexity during the nighttime than during the daytime; (ii) this difference may be lost if non-normalized indexes are utilized; (iii) the circadian pattern in the normalized indexes is lost in HF patients; (iv) in HF patients the loss of the day-night variation in the normalized indexes is related to a tendency of complexity to increase during the daytime and to decrease during the nighttime; (v) the most likely length L =3 indicates that stable patterns (i.e., those with no variations) are more present during the daytime, while highly variable patterns (i.e., those with two unlike variations) are more frequent during the nighttime; (vii) during the daytime in HF patients, the percentage of highly variable patterns increases with respect to NO subjects, while during the nighttime, the percentage of patterns with one or two like variations decreases.

  3. Characterization of a genotoxicity biomarker in three-spined stickleback (Gasterosteus aculeatus L.): Biotic variability and integration in a battery of biomarkers for environmental monitoring.

    PubMed

    Santos, Raphael; Joyeux, Aude; Palluel, Olivier; Palos-Ladeiro, Mélissa; Besnard, Aurélien; Blanchard, Christophe; Porcher, Jean Marc; Bony, Sylvie; Devaux, Alain; Sanchez, Wilfried

    2016-04-01

    As a large array of hazardous substances exhibiting genotoxicity are discharged into surface water, this work aimed at assessing the relevance of adding a genotoxicity biomarker in a battery of biomarkers recently developed in the model fish three-spined stickleback (Gasterosteus aculeatus). First the confounding influence of gender, body length, and season (used as a proxy of age and of the fish reproductive status, respectively) on the level of primary DNA damage in erythrocytes was investigated in wild sticklebacks. Then, the genotoxity biomarker was included in a large battery of biomarkers assessing xenobiotic biotransformation, oxidative stress and neurotoxicity, and implemented in five sites. Gender, age and reproductive status did not influence DNA damage level in fish from the reference site. A significant relationship between the level of primary DNA damage and fish length (as a proxy of age also correlated to the season) was highlighted in the contaminated site. Among all biomarkers investigated in the field, the level of DNA damage was one of the four most discriminating biomarkers with EROD, catalase activity and the level of lipid peroxidation representing together 75.40% of the discriminating power in sampled fish. The level of DNA damage was correlated to the EROD activity and to the level of peroxidation, which mainly discriminated fish from sites under urban pressure. Finally, Integrated Biomarker Response indexes (IBRv2), which were calculated with the whole biomarker response dataset exhibited higher values in the Reveillon (9.62), the Scarpe and Rhonelle contaminated sites (5.11 and 4.90) compared with the two reference sites (2.38 and 2.55). The present work highlights that integration of a genotoxicity biomarker in a multiparametric approach is relevant to assess ecotoxicological risk in freshwater aquatic organisms.

  4. Rain-based factors of high agricultural impacts over Senegal. Part I: integration of local to sub-regional trends and variability

    NASA Astrophysics Data System (ADS)

    Salack, S.; Muller, B.; Gaye, A. T.

    2011-11-01

    The evolution of seasonal cycle and interannual rainfall, the number of rainy days and daily rainfall types, dry spells frequency of occurrence, onset/cessation/length of rainy season, sowing dates, and the duration of the cropping period, are investigated at local (individual sites) and sub-regional scales (four different rainfall zones) using daily records of station data (83 sites) over Senegal. In the limits of a case study, these analyses complement and update previous studies conducted in the extreme Western Sahel (11-16° N and 20° W-10° E). The results unveil noticeable evolution of some of these rain-based factors in the recent periods as compared to the previous dry years. In the regions recording less than 800 mm/year (Sudan and Sahel sub-regions), the positive and statistically significant trends of rainfall amount are associated with new features of increasing frequency of short dry spell category, increasing number of some classes of extreme daily rainfall amounts and shifts in the peak number of rainy days. At sub-regional scales, the starting years (or change points) the magnitude and the signs of the new trends are unevenly distributed in the period post-1990. Earlier and higher amplitude changes are found at local scales and not less than one third of the sites in each sub-regional network are significantly affected. The extreme Southern sub-region exhibits no significant changes. Statistically significant trends are not observed on daily rain records ≤10 mm, onset/cessation dates, successful sowing dates, rainy season length, cropping period, medium and extreme dry spell categories. Rather, some of these factors such as the successful sowing date and the cropping season length exhibit significant variability. The onset (cessation) dates of the rainy season are followed (preceded) by extreme dry spell episodes. In the perspectives of climate impact assessments on the local agriculture a sub-regional periodic synopsis of the major rain

  5. Linking water quality to water quantity: Integration of disturbance variables such as phytoplankton and turbidity into the management strategies of drinking water reservoirs

    NASA Astrophysics Data System (ADS)

    Rolinski, S.; Petzoldt, T.; Hillert, K.; Paul, L.; Benndorf, J.

    2007-12-01

    So far, seasonal management strategies for water withdrawal from drinking water reservoirs in Germany are based on the hydrological regime and use Monte-Carlo-simulations in order to provide recommendations with certain probability thresholds. Long-term experience on the annual development and composition of phytoplankton is used for ad-hoc adjustments in case of unexpected events. In the framework of the project INTEGTA ('Integrated management of reservoirs') knowledge on the biological and chemical freshwater ecosystem will be integrated into the widely used management system TALSIM. On the one hand, field studies on the reservoir system Klingenberg-Lehnmuehle are carried out in order to investigate the seasonal development and the dispersion of flood events in the major drinking water supply of Dresden, Saxony. The system consists of two closely linked reservoirs which are connected to other water storages so that many possibilities for water supply exist. In the year 2007, an early hot spring and lower than average precipitation resulted in a summerly water deficiency in Klingenberg reservoir which was met with increased supply with a time lag of one month. Though the inflowing water was of high quality and low temperature, the quality of the raw water could not be stabilized on the desired level and caused the request for an administrative fine. Thus, 2007 can be taken as a good example for studying the effect of delayed management activities. On the other hand, simulations by the coupled hydrodynamical ecological model SALMO will provide the basis to include water quality predictions into the decision system for the reservoir. Hydrological scenarios from the decision support system TALSIM are used as boundary conditions for the water quality model so that consistent predictions for the development of the water quantity and quality are derived. The output of the simulations are statistically analyzed with respect to (i) securing a sufficient water volume, (ii

  6. Towards the development of multifunctional molecular indicators combining soil biogeochemical and microbiological variables to predict the ecological integrity of silvicultural practices.

    PubMed

    Peck, Vincent; Quiza, Liliana; Buffet, Jean-Philippe; Khdhiri, Mondher; Durand, Audrey-Anne; Paquette, Alain; Thiffault, Nelson; Messier, Christian; Beaulieu, Nadyre; Guertin, Claude; Constant, Philippe

    2016-05-01

    The impact of mechanical site preparation (MSP) on soil biogeochemical structure in young larch plantations was investigated. Soil samples were collected in replicated plots comprising simple trenching, double trenching, mounding and inverting site preparation. Unlogged natural mixed forest areas were used as a reference. Analysis of soil nutrients, abundance of bacteria and gas exchanges unveiled no significant difference among the plots. However, inverting site preparation resulted in higher variations of gas exchanges when compared with trenching, mounding and unlogged natural forest. A combination of the biological and physicochemical variables was used to define a multifunctional classification of the soil samples into four distinct groups categorized as a function of their deviation from baseline ecological conditions. According to this classification model, simple trenching was the approach that represented the lowest ecological risk potential at the microsite level. No relationship was observed between MSP method and soil bacterial community structure as assessed by high-throughput sequencing of bacterial 16S rRNA gene; however, indicator genotypes were identified for each multifunctional soil class. This is the first identification of multifunctional molecular indicators for baseline and disturbed ecological conditions in soil, demonstrating the potential of applied microbial ecology to guide silvicultural practices and ecological risk assessment.

  7. Profile of mood states and quality of life of Chinese postmastectomy women in Hong Kong: Integrating variable- and person-centered approaches.

    PubMed

    Shin, Kristina; Ganotice, Fraide A; Downing, Kevin; Yip, Lee Wai; Han, Fred; Yeo, Winnie; Suen, Joyce J S; Lee, Kun M; Ho, Simone S M; Soong, Sung Inda; Wong, Ka Yan; Kwok, Carol Chi Hei; Leung, Kaoru

    2016-08-01

    Understanding the mood state and its relationship with quality of life (QOL) of mastectomy recipients can serve as baseline within which a sound rehabilitation program can be developed. This study therefore was conducted to facilitate a better understanding of participants' postmastectomy mood states, identify their potential predictors, identify clusters of mood profiles, and clarify between-cluster differences in terms of QOL. Hong Kong mastectomy patients completed the Profile of Mood States and Ferrans and Powers Quality of Life Index. We extended the complementary strengths of the application of both variable- and person-centered approaches to clarify relationships and to identify profiles of mood states in relation to QOL in a sample of 200 women who had undergone a mastectomy in Hong Kong. Simultaneous regression identified age and educational attainment as predictors of mood states, and cluster analysis identified three distinct mood profiles that are able to explain differences in various measures of QOL after mastectomy. Implications for future research and practice are discussed.

  8. Integrability, solitons, periodic and travelling waves of a generalized (3+1)-dimensional variable-coefficient nonlinear-wave equation in liquid with gas bubbles

    NASA Astrophysics Data System (ADS)

    Deng, Gao-Fu; Gao, Yi-Tian

    2017-06-01

    Under investigation in this paper is a generalized (3+1)-dimensional varible-coefficient nonlinear-wave equation, which has been presented for nonlinear waves in liquid with gas bubbles. The bilinear form, Bäcklund transformation, Lax pair and infinitely-many conservation laws are obtained via the binary Bell polynomials. One-, two- and three-soliton solutions are generated by virtue of the Hirota method. Travelling-wave solutions are derived with the aid of the polynomial expansion method. The one-periodic wave solutions are constructed by the Hirota-Riemann method. Discussions among the soliton, periodic- and travelling-wave solutions are presented: I) the soliton velocities are related to the variable coefficients, while the soliton amplitudes are unaffected; II) the interaction between the solitons is elastic; III) there are three cases of the travelling-wave solutions, i.e., the triangle-type periodical, bell-type and soliton-type travelling-wave solutions, while we notice that bell-type travelling-wave solutions can be converted into one-soliton solutions via taking suitable parameters; IV) the one-periodic waves approach to the solitary waves under some conditions and can be viewed as a superposition of overlapping solitary waves, placed one period apart.

  9. Variability and situatedness of human emotions. Comment on "The quartet theory of human emotions: An integrative and neurofunctional model" by S. Koelsch et al.

    NASA Astrophysics Data System (ADS)

    Nadal, Marcos; Rosselló, Jaume

    2015-06-01

    We commend Koelsch and colleagues [14] for developing a broad and integrative explanation of the neurobiological foundations of emotions. We especially welcome this framework's emphasis on the interaction between language and emotion, and its focus on the characteristically human moral emotions. Emotions elicited by art and aesthetics also seem to be distinctively human, but comparatively little research has been devoted to understanding these. This is probably because they are usually viewed as atypical in several respects. William James [12], for instance, regarded emotional responses to artworks and aesthetic qualities as subtler emotions, because they lacked the strong bodily changes and adaptive value characteristic of coarser emotions, such as joy, anger, or fear. This view is still predominant today, and aesthetic emotions are often distinguished from everyday emotions [13]. However, the notion of a class of aesthetic emotions, separate from everyday emotions, rests on the questionable assumption that artistic and aesthetic experiences and activities are different in essence from everyday experiences and activities. The discontinuity between "aesthetic experience [and] normal processes of living" [9, p. 10], however, is the product of social and cultural developments in Europe during the 18th century [7,15,20]. Distinctions that oppose art to craft, or aesthetic to practical, in reference to objects, behaviors, experiences, and emotions, make little sense in a broader historic and geographic context [1,7,20], and hinder empirical research [7].

  10. Cataclysmic variable stars.

    NASA Astrophysics Data System (ADS)

    Warner, B.

    The study of cataclysmic variables - interacting binary stars containing a white dwarf accreting from an companion - is undergoing an exciting renaissance, as it embraces observations at all wavelengths. Cataclysmic variables allow, in particular, the direct and detailed study of equilibrium and non-equilibrium accretion discs; in turn this also helps in our understanding of X-ray binaries, black holes and active galactic nuclei. This timely volume provides the first comprehensive survey of cataclysmic variable stars, integrating theory and observation into a single, synthesized text. An introductory chapter gives the historical background of studies of cataclysmic variables. The author then goes on to give an up-to-date review of both the observations (at all wavelengths, and over all time scales) and the theories and models of the structures and accretion processes believed to be involved. A detailed bibliography is also provided to guide the reader to pertinent primary literature.

  11. Integrating experimental studies of hydrous mantle melting with numerical models of the global variability in the temperature - depth structure of the mantle wedge

    NASA Astrophysics Data System (ADS)

    Grove, T. L.; Till, C. B.; van Keken, P.

    2012-12-01

    The H2O-saturated peridotite melting experiments of Till et al. (2012, CMP, 163, 669) and Grove et al. (2006, EPSL, 249, 74) provide new information on hydrous mineral phase stability and melting temperatures in the mantle wedge beneath arc volcanoes. Recent thermal models (Syracuse et al., 2010, PEPI 183, 73) and estimates of H2O flux from the subducting lithosphere (van Keken et al., 2011, JGR 116, B01401) permit estimates of the amount of H2O that can be bound in hydrous minerals (predominantly chlorite) in the wedge and the subducted lithosphere. Combining the information from both studies provides insights into where water is stored in the subduction zone system, how it is transported up into the mantle wedge and how melting begins in the mantle and/or subducted slab. The global variability in slab convergence rate, age, dip, rollback, etc. affects the temperature structure in the mantle wedge and subducted slab. By mapping the experimental phase relations onto the predicted temperature - depth variations some interesting systematics arise. We predict that chlorite will be stable in a 1 km thick layer in the mantle wedge above the slab-wedge interface in the hottest subduction zones and up to 1.5 km thick layer in the coldest subduction zones. In the warmer subduction zones the hydrous minerals in the slab will break down at shallow depths but if serpentine and chlorite are present in the mantle underneath the slab, both will remain stable until between 55 and 100 km depth. When these hydrous minerals break down, the resulting water will ascend through the overlying slab and the mantle wedge and trigger vapor-saturated flux melting of the mantle wedge. In colder subduction zones, chlorite stable in the mantle wedge will bind and store any free H2O until it breaks down. Thus, in cold subduction zones we predict chlorite dehydration melting in the overlying mantle wedge to be the dominant form of hydrous melting. P-T paths for the slab surface in the warmest

  12. Estimating TCR using an integrated model-observation framework that accounts for spatio-temporal variability and pre-industrial radiative imbalances.

    NASA Astrophysics Data System (ADS)

    Haustein, K.; Schurer, A. P.; Venema, V.

    2016-12-01

    Apart from a few exceptions (e.g. Aldrin et al. 2012, Skeie et al. 2013) TCR estimates with EBMs are based on global data. Since these estimates don't represent the true spatial-temporal behaviour for observed temperature as well as external forcing (Marvel et al. 2015), we have developed a two-box EBM framework that accounts for these effects. In addition, external forcing from anthropogenic aerosol and GHGs tends to have different response times in comparison to volcanic stratospheric aerosols. Using PMIP3 and an extended ensemble of HadCM3 simulations (Euro500; Schurer et al. 2014) GCM simulations for the pre-industrial period, we obtain the fast and slow response time constants required in the EBM. With the most recent anthropogenic and natural forcing estimates, we test a range of TCR values against observations. The TCR/ECS ratio necessary to achieve that goal is taken from CMIP5 as observationally OHC-based estimates are notoriously unreliable. Given that observed and modelled OHC estimates are in agreement (Cheng et al. 2016), we argue that this should be the standard procedure the make inferences about ECS. Alternatively, it should be distinguished between equilibrium and effective climate sensitivity. The preliminary best estimate for TCR is 1.6K (1.1-2.2K) with an associated ECS value of 2.9K (2.0-4.0K). This is in good agreement with other D&A techniques that do use spatio-temporal patterns as well (e.g. Jones et al. 2016, Gillet et al. 2013). Correcting for natural ENSO variability and tas/tos-related inaccuracies (Richardson et al. 2016) further increases the robustness of the estimated sensitivity range. Our results also indicate that the small radiative imbalance caused by the period of very strong volcanic eruptions just before the CMIP5 historical period starts (1809-1840) has noteworthy implications for the response to later volcanic eruptions and the temperature evolution after 1850. Simply put, CMIP5-type simulations are slightly more sensitive

  13. Dosimetric response of variable-size cavities in photon-irradiated media and the behaviour of the Spencer-Attix cavity integral with increasing Δ.

    PubMed

    Kumar, Sudhir; Deshpande, Deepak D; Nahum, Alan E

    2016-04-07

    Cavity theory is fundamental to understanding and predicting dosimeter response. Conventional cavity theories have been shown to be consistent with one another by deriving the electron (+positron) and photon fluence spectra with the FLURZnrc user-code (EGSnrc Monte-Carlo system) in large volumes under quasi-CPE for photon beams of 1 MeV and 10 MeV in three materials (water, aluminium and copper) and then using these fluence spectra to evaluate and then inter-compare the Bragg-Gray, Spencer-Attix and 'large photon' 'cavity integrals'. The behaviour of the 'Spencer-Attix dose' (aka restricted cema), D S-A(▵), in a 1-MeV photon field in water has been investigated for a wide range of values of the cavity-size parameter ▵: D S-A(▵) decreases far below the Monte-Carlo dose (D MC) for ▵ greater than  ≈  30 keV due to secondary electrons with starting energies below ▵ not being 'counted'. We show that for a quasi-scatter-free geometry (D S-A(▵)/D MC) is closely equal to the proportion of energy transferred to Compton electrons with initial (kinetic) energies above ▵, derived from the Klein-Nishina (K-N) differential cross section. (D S-A(▵)/D MC) can be used to estimate the maximum size of a detector behaving as a Bragg-Gray cavity in a photon-irradiated medium as a function of photon-beam quality (under quasi CPE) e.g. a typical air-filled ion chamber is 'Bragg-Gray' at (monoenergetic) beam energies  ⩾260 keV. Finally, by varying the density of a silicon cavity (of 2.26 mm diameter and 2.0 mm thickness) in water, the response of different cavity 'sizes' was simulated; the Monte-Carlo-derived ratio D w/D Si for 6 MV and 15 MV photons varied from very close to the Spencer-Attix value at 'gas' densities, agreed well with Burlin cavity theory as ρ increased, and approached large photon behaviour for ρ  ≈  10 g cm(-3). The estimate of ▵ for the Si cavity was improved by incorporating a Monte-Carlo-derived correction for

  14. Variable Radius Nacelle Studies

    NASA Technical Reports Server (NTRS)

    McGowan, David M.

    2001-01-01

    An overview of the active shape control for a variable radius nacelle leading edge program is presented. The current technical plan and schedule will be discussed. Results from the structural shape change of curved plates demonstration will be presented, as well as the NASA LaRC concept for a variable radius nacelle leading edge. Results of a Boeing systems integration study of this concept will be discussed briefly. The status of the sensors, actuators, and computational design tools tasks will also be presented.

  15. Spatial and temporal variabilities in vertical structure of the Marine Atmospheric Boundary Layer over Bay of Bengal during Winter Phase of Integrated Campaign for Aerosols, gases and Radiation Budget

    NASA Astrophysics Data System (ADS)

    Subrahamanyam, D. Bala; Anurose, T. J.; Kumar, N. V. P. Kiran; Mohan, Mannil; Kunhikrishnan, P. K.; John, Sherine Rachel; Prijith, S. S.; Dutt, C. B. S.

    2012-04-01

    Spatial and temporal variabilities in the vertical structure of Marine Atmospheric Boundary Layer (MABL) over the Bay of Bengal (BoB) are investigated through a ship-borne field experiment measurements pertaining to three different classes, namely: night, morning and afternoon conditions. High-resolution vertical profiles of meteorological parameters obtained through balloon-borne GPS Sondes during the Winter phase of Integrated Campaign for Aerosols, gases and Radiation Budget (W-ICARB) formed the primary database for the present investigation. The study advocates usage of wind shear profiles in association with virtual potential temperature (θv) and specific humidity (q) profiles for determination of the mixed layer heights (MLH). The mean values of turbulent flow thickness (TFT) obtained from the vertical profiles of Bulk Richardson Number (RiB) and MLH magnitudes for the entire cruise did not show any appreciable variations for three classes. During the entire cruise period, the MLH varied in a range from 450 m to 1500 m with a mean of about 900 m, whereas the TFT variations were confined between 125 m and 1475 m with a mean of about 581 m. The statistical means of TFT and MLH were similar for nighttime profiles, whereas they showed significant differences in the morning and afternoon conditions. Spatio-temporal variability in the MLH showed good correlation with the surface-layer sensible heat flux which is one of the driving mechanisms in mixing processes.

  16. Functional Integration

    NASA Astrophysics Data System (ADS)

    Cartier, Pierre; DeWitt-Morette, Cecile

    2010-06-01

    Acknowledgements; List symbols, conventions, and formulary; Part I. The Physical and Mathematical Environment: 1. The physical and mathematical environment; Part II. Quantum Mechanics: 2. First lesson: gaussian integrals; 3. Selected examples; 4. Semiclassical expansion: WKB; 5. Semiclassical expansion: beyond WKB; 6. Quantum dynamics: path integrals and operator formalism; Part III. Methods from Differential Geometry: 7. Symmetries; 8. Homotopy; 9. Grassmann analysis: basics; 10. Grassmann analysis: applications; 11. Volume elements, divergences, gradients; Part IV. Non-Gaussian Applications: 12. Poisson processes in physics; 13. A mathematical theory of Poisson processes; 14. First exit time: energy problems; Part V. Problems in Quantum Field Theory: 15. Renormalization 1: an introduction; 16. Renormalization 2: scaling; 17. Renormalization 3: combinatorics; 18. Volume elements in quantum field theory Bryce DeWitt; Part VI. Projects: 19. Projects; Appendix A. Forward and backward integrals: spaces of pointed paths; Appendix B. Product integrals; Appendix C. A compendium of gaussian integrals; Appendix D. Wick calculus Alexander Wurm; Appendix E. The Jacobi operator; Appendix F. Change of variables of integration; Appendix G. Analytic properties of covariances; Appendix H. Feynman's checkerboard; Bibliography; Index.

  17. Classical integrability

    NASA Astrophysics Data System (ADS)

    Torrielli, Alessandro

    2016-08-01

    We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  18. VARIABLE SPEED INTEGRATED INTELLIGENT HVAC BLOWER

    SciTech Connect

    Herman Wiegman; Charlie Stephens; Xiaoyue Liu; Ralph Carl; Sunny Zhuang; Paul Szczesny; Kamron Wright

    2003-09-23

    This comprehensive topical report discusses the key findings in the development of an advanced blower for HVAC applications. The benefits of rearward inclined blades over that of traditional forward inclined blades is well documented, and several prototype wheels are demonstrated in various housings. A comparison of retrofitted blowers to that of three typical units from the industry is presented. The design and modification of the blower housing is addressed and the impact of size limitations on static efficiency is discussed. The roadmap to rearward-inclined wheel technology insertion is presented and typical static efficiency gains are documented.

  19. Glucose Variability

    PubMed Central

    Le Floch, Jean-Pierre; Kessler, Laurence

    2016-01-01

    Background: Glucose variability has been suspected to be a major factor of diabetic complications. Several indices have been proposed for measuring glucose variability, but their interest remains discussed. Our aim was to compare different indices. Methods: Glucose variability was studied in 150 insulin-treated diabetic patients (46% men, 42% type 1 diabetes, age 52 ± 11 years) using a continuous glucose monitoring system (668 ± 564 glucose values; mean glucose value 173 ± 38 mg/dL). Results from the mean, the median, different indices (SD, MAGE, MAG, glucose fluctuation index (GFI), and percentages of low [<60 mg/dL] and high [>180 mg/dL] glucose values), and ratios (CV = SD/m, MAGE/m, MAG/m, and GCF = GFI/m) were compared using Pearson linear correlations and a multivariate principal component analysis (PCA). Results: CV, MAGE/m (ns), GCF and GFI (P < .05), MAG and MAG/m (P < .01) were not strongly correlated with the mean. The percentage of high glucose values was mainly correlated with indices. The percentage of low glucose values was mainly correlated with ratios. PCA showed 3 main axes; the first was associated with descriptive data (mean, SD, CV, MAGE, MAGE/m, and percentage of high glucose values); the second with ratios MAG/m and GCF and with the percentage of low glucose values; and the third with MAG, GFI, and the percentage of high glucose values. Conclusions: Indices and ratios provide complementary pieces of information associated with high and low glucose values, respectively. The pairs MAG+MAG/m and GFI+GCF appear to be the most reliable markers of glucose variability in diabetic patients. PMID:26880391

  20. QT variability.

    PubMed

    Berger, Ronald D

    2003-01-01

    We hypothesized that temporal lability in ventricular repolarization is a marker for, and is mechanistically related to, increased risk of malignant ventricular arrhythmias. To assess repolarization lability in the surface electrocardiogram, we developed an automated algorithm, based on template matching, to measure beat-to-beat changes in QT interval. We calculate a QT variability index (QTVI) to quantify the relative magnitude of QT interval changes compared to heart rate variability. We found that QTVI is a reproducible measure. It is elevated in patients with ischemic and nonischemic dilated cardiomyopathy compared with age-matched controls (P<.00001). We have also shown that QTVI is elevated in patients with malignant beta-myosin heavy-chain mutations associated with hypertrophic cardiomyopathy. In a study of patients undergoing electrophysiologic testing, QTVI identified patients with cardiac arrest better than electrophysiologic test result and better than other risk stratifiers included in the analysis. QT variability is a marker of electrical disease in the ventricle and may be associated with enhanced risk of life-threatening arrhythmias.

  1. Variable Permanent Magnet Quadrupole

    SciTech Connect

    Mihara, T.; Iwashita, Y.; Kumada, M.; Spencer, C.M.; /SLAC

    2007-05-23

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

  2. The universal path integral

    NASA Astrophysics Data System (ADS)

    Lloyd, Seth; Dreyer, Olaf

    2016-02-01

    Path integrals calculate probabilities by summing over classical configurations of variables such as fields, assigning each configuration a phase equal to the action of that configuration. This paper defines a universal path integral, which sums over all computable structures. This path integral contains as sub-integrals all possible computable path integrals, including those of field theory, the standard model of elementary particles, discrete models of quantum gravity, string theory, etc. The universal path integral possesses a well-defined measure that guarantees its finiteness. The probabilities for events corresponding to sub-integrals can be calculated using the method of decoherent histories. The universal path integral supports a quantum theory of the universe in which the world that we see around us arises out of the interference between all computable structures.

  3. Changes in Heart Rate Variability Recorded in Natural Situation with T-Shirt Integrated Sensors and Level of Observed Behavioral Excitation: A Pilot Study of Patients with Intellectual Disabilities and Psychiatric Disorders.

    PubMed

    Palix, Julie; Akselrod, Michel; Cungi, Charly; Giuliani, Fabienne; Favrod, Jérôme

    2017-01-01

    The present study investigates the possibilities of using heart rate variability (HRV) parameters as physiological markers that precede increase in observed behavioral excitation of intellectually disabled individuals. The ability to recognize or predict such patterns, especially in patients showing unpredictable reactions and language deficiencies, might be a major step forward in clinical research. Thirteen volunteers with intellectual disabilities, who had suffered of at least one event of overt aggression in the preceding 3 months, participated to the study. The protocol consists in the acquisition of continuous electrocardiogram (ECG) throughout approximately two times of 8 h in natural situation, using a T-shirt integrated with sensors. Simultaneously, an observer evaluates the patient's level of overt excitation from calm (level 1) to extremely tense (level 5) and send online via Bluetooth these triggers into the ECG signals. The HRV indexes were then estimated offline on the basis of the inter-beat intervals recorded by the ECG, independently for the 30 min preceding each behavioral tension marking point, averaged, and compared through non-parametric Wilcoxon matched-pairs test. Of these, the RMSSD and LF/HF calculations were used to observe the fluctuations of inhibitory activity and cardiovagal balance through different tension states. Seven individuals have sufficient reliable data for analysis. They have reached at least a level 3 of behavioral excitation (moderately tense) or more (very to extremely tense, level 4 and 5) and have been retained for further analysis. In sum, a total of 197 periods of tension were kept, made up of 46 periods of slight excitation (level 2), 18 of moderate excitation (level 3), 10 of high excitation (level 4), and 5 of extreme agitation (level 5). Variations in the HRV as a function of degree of excitation are observed for RMSSD index only (inhibitory parasympathetic activity). The changes from calm to increasing

  4. Applying Change of Variable to Calculus Problems

    ERIC Educational Resources Information Center

    Kachapova, Farida; Kachapov, Ilias

    2011-01-01

    This article describes the technique of introducing a new variable in some calculus problems to help students master the skills of integration and evaluation of limits. This technique is algorithmic and easy to apply.

  5. Remarriage and Integration within the Community.

    ERIC Educational Resources Information Center

    Ihinger-Tallman, Marilyn; Pasley, Kay

    1986-01-01

    Examined relationship between social characteristics of remarried persons and community integration. When measures of community integration were regressed upon all independent variables, the type of marriage did not have an effect on any of the measures. However, when the type of remarriage was a control variable, different integration patterns…

  6. Modeling Pacific Decadal Variability

    NASA Astrophysics Data System (ADS)

    Schneider, N.

    2002-05-01

    Hypotheses for decadal variability rely on the large thermal inertia of the ocean to sequester heat and provide the long memory of the climate system. Understanding decadal variability requires the study of the generation of ocean anomalies at decadal frequencies, the evolution of oceanic signals, and the response of the atmosphere to oceanic perturbations. A sample of studies relevant for Pacific decadal variability will be reviewed in this presentation. The ocean integrates air-sea flux anomalies that result from internal atmospheric variability or broad-band coupled processes such as ENSO, or are an intrinsic part of the decadal feedback loop. Anomalies of Ekman pumping lead to deflections of the ocean thermocline and accompanying changes of the ocean circulation; perturbations of surface layer heat and fresh water budgets cause anomalies of T/S characteristics of water masses. The former process leads to decadal variability due to the dynamical adjustment of the mid latitude gyres or thermocline circulation; the latter accounts for the low frequency climate variations by the slow propagation of anomalies in the thermocline from the mid-latitude outcrops to the equatorial upwelling regions. Coupled modeling studies and ocean model hindcasts suggest that the adjustment of the North Pacific gyres to variation of Ekman pumping causes low frequency variations of surface temperature in the Kuroshio-Oyashio extension region. These changes appear predictable a few years in advance, and affect the local upper ocean heat budget and precipitation. The majority of low frequency variance is explained by the ocean's response to stochastic atmospheric forcing, the additional variance explained by mid-latitude ocean to atmosphere feedbacks appears to be small. The coupling of subtropical and tropical regions by the equator-ward motion in the thermocline can support decadal anomalies by changes of its speed and path, or by transporting water mass anomalies to the equatorial

  7. Calculus with a quaternionic variable

    NASA Astrophysics Data System (ADS)

    Schwartz, Charles

    2009-01-01

    Most of theoretical physics is based on the mathematics of functions of a real or a complex variable; yet we frequently are drawn in trying to extend our reach to include quaternions. The noncommutativity of the quaternion algebra poses obstacles for the usual manipulations of calculus, but we show in this paper how many of those obstacles can be overcome. The surprising result is that the first order term in the expansion of F(x +δ) is a compact formula involving both F'(x) and [F(x )-F(x∗)]/(x -x∗). This advance in the differential calculus for quaternionic variables also leads us to some progress in studying integration.

  8. Gauge Integration

    DTIC Science & Technology

    2002-09-01

    convergence theorems. Lebesgue developed his theory of measure and integration to address these shortcomings. His integral is more powerful in the...This relatively recent integral possesses the intuitive description of the Riemann integral, with the power of the Lebesgue integral. The purpose of this...strong convergence theorems. Lebesgue developed his theory of measure and integration to address these shortcomings. His integral is more powerful in the

  9. Integrated Means Integrity

    ERIC Educational Resources Information Center

    Odegard, John D.

    1978-01-01

    Describes the operation of the Cessna Pilot Center (CPC) flight training systems. The program is based on a series of integrated activities involving stimulus, response, reinforcement and association components. Results show that the program can significantly reduce in-flight training time. (CP)

  10. Integrated Means Integrity

    ERIC Educational Resources Information Center

    Odegard, John D.

    1978-01-01

    Describes the operation of the Cessna Pilot Center (CPC) flight training systems. The program is based on a series of integrated activities involving stimulus, response, reinforcement and association components. Results show that the program can significantly reduce in-flight training time. (CP)

  11. Integrating Mediators and Moderators in Research Design

    ERIC Educational Resources Information Center

    MacKinnon, David P.

    2011-01-01

    The purpose of this article is to describe mediating variables and moderating variables and provide reasons for integrating them in outcome studies. Separate sections describe examples of moderating and mediating variables and the simplest statistical model for investigating each variable. The strengths and limitations of incorporating mediating…

  12. On Quantum Integrable Systems

    SciTech Connect

    Danilov, Viatcheslav; Nagaitsev, Sergei; /Fermilab

    2011-11-01

    Many quantum integrable systems are obtained using an accelerator physics technique known as Ermakov (or normalized variables) transformation. This technique was used to create classical nonlinear integrable lattices for accelerators and nonlinear integrable plasma traps. Now, all classical results are carried over to a nonrelativistic quantum case. In this paper we have described an extension of the Ermakov-like transformation to the Schroedinger and Pauli equations. It is shown that these newly found transformations create a vast variety of time dependent quantum equations that can be solved in analytic functions, or, at least, can be reduced to time-independent ones.

  13. Tropical Pacific moisture variability

    NASA Technical Reports Server (NTRS)

    Mcguirk, James P.

    1990-01-01

    The objectives are to describe synoptic scale variability of moisture over the tropical Pacific Ocean and the systems leading to this variability; implement satellite analysis procedures in support of this effort, and to incorporate additional satellite information into operational analysis forecast systems at the National Meteorological Center (NMC). Composite satellite radiance patterns describe features detectable well before the development of synoptic scale tropical plumes. These typical features were extracted from historical files of Tiros Operational Vertical Sounder (TOVS) radiance observations for a pair of tropical plumes which developed during January 1989. Signals were inserted into the NMC operational medium range forecast model and a suite of model integrations were conducted. Many of the 48 h model errors of the historical forecasts were eliminated by the inclusion of more complete satellite observations. Three studies in satellite radiance analysis progressed. An analysis which blended TOVS moisture channels, OLR observations and European Center for Medium Weather Forecasts (ECMWF) model analysis to generate fields of total precipitable water comparable to those estimated from Scanning Multichannel Microwave Radiometer (SMMR) mu-wave observations. This study demonstrated that a 10 y climatology of precipitable water over the oceans is feasible, using available infrared observations (OLR and TOVS) and model analysis (ECMWF, NMC or similar quality). The estimates are sensitive to model quality and the estimating model must be updated with operational model changes. Coe developed a set of tropical plume and ITCZ composites from TOVS observations, and from NMC and ECMWF analyses which had been passed through a radiative transfer model to simulate TOVS radiances. The composites have been completed as well as many statistical diagnostics of individual TOVS channels. Analysis of the computations is commencing. Chung has initiated a study of the

  14. Integrated control-structure design

    NASA Technical Reports Server (NTRS)

    Hunziker, K. Scott; Kraft, Raymond H.; Bossi, Joseph A.

    1991-01-01

    A new approach for the design and control of flexible space structures is described. The approach integrates the structure and controller design processes thereby providing extra opportunities for avoiding some of the disastrous effects of control-structures interaction and for discovering new, unexpected avenues of future structural design. A control formulation based on Boyd's implementation of Youla parameterization is employed. Control design parameters are coupled with structural design variables to produce a set of integrated-design variables which are selected through optimization-based methodology. A performance index reflecting spacecraft mission goals and constraints is formulated and optimized with respect to the integrated design variables. Initial studies have been concerned with achieving mission requirements with a lighter, more flexible space structure. Details of the formulation of the integrated-design approach are presented and results are given from a study involving the integrated redesign of a flexible geostationary platform.

  15. Integrating Art.

    ERIC Educational Resources Information Center

    BCATA Journal for Art Teachers, 1991

    1991-01-01

    These articles focus on art as a component of interdisciplinary integration. (1) "Integrated Curriculum and the Visual Arts" (Anna Kindler) considers various aspects of integration and implications for art education. (2) "Integration: The New Literacy" (Tim Varro) illustrates how the use of technology can facilitate…

  16. Breakpoint analysis and relations of nutrient and turbidity stressor variables to macroinvertebrate integrity in streams in the Crawford-Mammoth Cave Uplands Ecoregion, Kentucky, for the development of nutrient criteria

    USGS Publications Warehouse

    Crain, Angela S.; Caskey, Brian J.

    2010-01-01

    To assist Kentucky in refining numeric nutrient criteria in the Pennyroyal Bioregion, the U.S. Geological Survey and the Kentucky Division of Water collected and analyzed water chemistry, turbidity, and biological-community data from 22 streams throughout the Crawford-Mammoth Cave Upland ecoregion (U.S. Environmental Protection Agency Level IV Ecoregion, 71a) within the Pennyroyal Bioregion from September 2007 to May 2008. Statistically significant and ecologically relevant relations among the stressor (total phosphorus, total nitrogen, and turbidity) variables and response (macroinvertebrate-community attributes) variables and the breakpoint values of biological-community attributes and metrics in response to changes in stressor variables were determined. Thirteen of 18 macroinvertebrate attributes were significantly and ecologically correlated (p-value < 0.10) with at least one nutrient measure. Total number of individuals, Ephemeroptera-Plecoptera-Trichoptera richness, and average tolerance value were macroinvertebrate measures that most strongly correlated with the concentrations of nutrients. Comparison of the average macroinvertebrate-breakpoint value for the median concentration of total phosphorus (TP, 0.033 mg/L) and for median concentration of total nitrogen (TN, 1.1 mg/L) to Dodds' trophic classification for TP and TN indicates streams in the Crawford-Mammoth Cave Uplands ecoregion within the Pennyroyal Bioregion would be classified as mesotrophic-eutrophic. The biological breakpoint relations with median concentrations of TP in this study were similar to the U.S. Environmental Protection Agency proposed numeric TP criteria (0.037 mg/L), but were 1.5 times higher than the proposed numeric criteria for concentrations of TN (0.69 mg/L). No sites were impacted adversely using median turbidity values based on a 25 Formazin nephelometric turbidity unit biological threshold. The breakpoints determined in this study, in addition to Dodds' trophic

  17. Numerical integration routines for near-earth operations

    NASA Technical Reports Server (NTRS)

    Powers, W. F.

    1973-01-01

    Two general purpose numerical integration schemes were built into the NASA-JSC computer system. The state-of-the-art of numerical integration, the particular integrators built into the JSC computer system, and the use of the new integration packages are described. Background information about numerical integration and the variable-order, variable-stepsize Adams numerical integration technique is discussed. Results concerning the PEACE parameter optimization program are given along with recommendations and conclusions.

  18. Simulating solar power plant variability :

    SciTech Connect

    Lave, Matthew Samuel; Ellis, Abraham; Stein, Joshua.

    2013-06-01

    It is important to be able to accurately simulate the variability of solar PV power plants for grid integration studies. We aim to inform integration studies of the ease of implementation and application-specific accuracy of current PV power plant output simulation methods. This report reviews methods for producing simulated high-resolution (sub-hour or even sub-minute) PV power plant output profiles for variability studies and describes their implementation. Two steps are involved in the simulations: estimation of average irradiance over the footprint of a PV plant and conversion of average irradiance to plant power output. Six models are described for simulating plant-average irradiance based on inputs of ground-measured irradiance, satellite-derived irradiance, or proxy plant measurements. The steps for converting plant-average irradiance to plant power output are detailed to understand the contributions to plant variability. A forthcoming report will quantify the accuracy of each method using application-specific validation metrics.

  19. A framework for assessing inter-individual variability in pharmacokinetics using virtual human populations and integrating general knowledge of physical chemistry, biology, anatomy, physiology and genetics: A tale of 'bottom-up' vs 'top-down' recognition of covariates.

    PubMed

    Jamei, Masoud; Dickinson, Gemma L; Rostami-Hodjegan, Amin

    2009-01-01

    An increasing number of failures in clinical stages of drug development have been related to the effects of candidate drugs in a sub-group of patients rather than the 'average' person. Expectation of extreme effects or lack of therapeutic effects in some subgroups following administration of similar doses requires a full understanding of the issue of variability and the importance of identifying covariates that determine the exposure to the drug candidates in each individual. In any drug development program the earlier these covariates are known the better. An important component of the drive to decrease this failure rate in drug development involves attempts to use physiologically-based pharmacokinetics 'bottom-up' modeling and simulation to optimize molecular features with respect to the absorption, distribution, metabolism and elimination (ADME) processes. The key element of this approach is the separation of information on the system (i.e. human body) from that of the drug (e.g. physicochemical characteristics determining permeability through membranes, partitioning to tissues, binding to plasma proteins or affinities toward certain enzymes and transporter proteins) and the study design (e.g. dose, route and frequency of administration, concomitant drugs and food). In this review, the classical 'top-down' approach in covariate recognition is compared with the 'bottom-up' paradigm. The determinants and sources of inter-individual variability in different stages of drug absorption, distribution, metabolism and excretion are discussed in detail. Further, the commonly known tools for simulating ADME properties are introduced.

  20. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

    Mosher, Michael; Vassallo, Andrew; Lewis, John F.; Campbell, Melissa

    2014-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multipule suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development and integrated testing of the suit loop regulator for Orion.

  1. Integrating Hydrologic and Water Quality Models as a Decision Support Tool for Implementation of Low Impact Development in a Coastal Urban Watershed under Climate Variability and Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Chang, N. B.

    2016-12-01

    Many countries concern about development and redevelopment efforts in urban regions to reduce the flood risk by considering hazards such as high-tide events, storm surge, flash floods, stormwater runoff, and impacts of sea level rise. Combining these present and future hazards with vulnerable characteristics found throughout coastal communities such as majority low-lying areas and increasing urban development, create scenarios for increasing exposure of flood hazard. As such, the most vulnerable areas require adaptation strategies and mitigation actions for flood hazard management. In addition, in the U.S., Numeric Nutrient Criteria (NNC) are a critical tool for protecting and restoring the designated uses of a waterbody with regard to nitrogen and phosphorus pollution. Strategies such as low impact development (LID) have been promoted in recent years as an alternative to traditional stormwater management and drainage to control both flooding and water quality impact. LID utilizes decentralized multifunctional site designs and incorporates on-site storm water management practices rather than conventional storm water management approaches that divert flow toward centralized facilities. How to integrate hydrologic and water quality models to achieve the decision support becomes a challenge. The Cross Bayou Watershed of Pinellas County in Tampa Bay, a highly urbanized coastal watershed, is utilized as a case study due to its sensitivity to flood hazards and water quality management within the watershed. This study will aid the County, as a decision maker, to implement its stormwater management policy and honor recent NNC state policy via demonstration of an integrated hydrologic and water quality model, including the Interconnected Channel and Pond Routing Model v.4 (ICPR4) and the BMPTRAIN model as a decision support tool. The ICPR4 can be further coupled with the ADCIRC/SWAN model to reflect the storm surge and seal level rise in coastal regions.

  2. Types of biological variables.

    PubMed

    Mayya, Shreemathi S; Monteiro, Ashma D; Ganapathy, Sachit

    2017-06-01

    Identification and description of variables used in any study is a necessary component in biomedical research. Statistical analyses rely on the type of variables that are involved in the study. In this short article, we introduce the different types of biological variables. A researcher has to be familiar with the type of variable he/she is dealing with in his/her research to decide about appropriate graphs/diagrams, summary measures and statistical analysis.

  3. Variable rate irrigation (VRI)

    USDA-ARS?s Scientific Manuscript database

    Variable rate irrigation (VRI) technology is now offered by all major manufacturers of moving irrigation systems, mostly on center pivot irrigation systems. Variable irrigation depths may be controlled by sector only, in which case only the speed of the irrigation lateral is regulated. Or, variable ...

  4. Variability as an Operant?

    ERIC Educational Resources Information Center

    Holth, Per

    2012-01-01

    A series of experiments on operant variability by Neuringer and colleagues (e.g., Neuringer, 1986, 2002; Page & Neuringer, 1985) have been repeatedly cited as showing that behavioral variability can be reinforced by making reinforcement contingent on it. They showed that the degree of variability in pigeons' eight-peck sequences, as measured by U…

  5. Understanding and identifying variability

    USDA-ARS?s Scientific Manuscript database

    Variability is the quality of being uneven or lacking uniformity. Understanding the causes, magnitude, and strategies to manage variability within crop production settings can be used to directly improve agricultural production systems. Identifying when the magnitude of variability is high enough to...

  6. Variability as an Operant?

    ERIC Educational Resources Information Center

    Holth, Per

    2012-01-01

    A series of experiments on operant variability by Neuringer and colleagues (e.g., Neuringer, 1986, 2002; Page & Neuringer, 1985) have been repeatedly cited as showing that behavioral variability can be reinforced by making reinforcement contingent on it. They showed that the degree of variability in pigeons' eight-peck sequences, as measured by U…

  7. Singular integrals related to the Radon transform and boundary value problems.

    PubMed

    Phong, D H; Stein, E M

    1983-12-01

    Two classes of integral operators are introduced that combine features of Calderón-Zygmund singular integrals, the Hilbert integral, and the Radon transform. Examples and applications arising from integral geometry and several complex variables are discussed.

  8. Singular integrals related to the Radon transform and boundary value problems

    PubMed Central

    Phong, D. H.; Stein, E. M.

    1983-01-01

    Two classes of integral operators are introduced that combine features of Calderón—Zygmund singular integrals, the Hilbert integral, and the Radon transform. Examples and applications arising from integral geometry and several complex variables are discussed. PMID:16593402

  9. Observed variability of the solar luminosity

    NASA Astrophysics Data System (ADS)

    Hudson, H. S.

    Data on solar luminosity variations are compiled in graphs and analyzed, with a focus on the SMM satellite bolometric measurements and other observations made since 1983. Consideration is given to total irradiance measurements in integrated light; emission-line variability in the visible, UV, and IR; mechanisms contributing to the solar variability (sunspots, faculae, rotation, oscillations, granulation, and active networks); the role of the solar magnetic cycle; and other observable parameters indicating variability. Also discussed are the effects of solar variations on the earth climate and the implications of the observations for theoretical models of convective-envelope processes (thermal diffusion near the surface and magnetic pressure in the interior).

  10. Sleep variability in adolescence is associated with altered brain development.

    PubMed

    Telzer, Eva H; Goldenberg, Diane; Fuligni, Andrew J; Lieberman, Matthew D; Gálvan, Adriana

    2015-08-01

    Despite the known importance of sleep for brain development, and the sharp increase in poor sleep during adolescence, we know relatively little about how sleep impacts the developing brain. We present the first longitudinal study to examine how sleep during adolescence is associated with white matter integrity. We find that greater variability in sleep duration one year prior to a DTI scan is associated with lower white matter integrity above and beyond the effects of sleep duration, and variability in bedtime, whereas sleep variability a few months prior to the scan is not associated with white matter integrity. Thus, variability in sleep duration during adolescence may have long-term impairments on the developing brain. White matter integrity should be increasing during adolescence, and so sleep variability is directly at odds with normative developmental trends.

  11. Teaching Integrity

    ERIC Educational Resources Information Center

    Saunders, Sue; Butts, Jennifer Lease

    2011-01-01

    Integrity is one of those essential yet highly ambiguous concepts. For the purpose of this chapter, integrity is defined as that combination of both attributes and actions that makes entities appear to be whole and ethical, as well as consistent. Like the concepts of leadership or wisdom or community or collaboration, integrity is a key element of…

  12. Application of Molecular Typing Results in Source Attribution Models: The Case of Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) of Salmonella Isolates Obtained from Integrated Surveillance in Denmark.

    PubMed

    de Knegt, Leonardo V; Pires, Sara M; Löfström, Charlotta; Sørensen, Gitte; Pedersen, Karl; Torpdahl, Mia; Nielsen, Eva M; Hald, Tine

    2016-03-01

    Salmonella is an important cause of bacterial foodborne infections in Denmark. To identify the main animal-food sources of human salmonellosis, risk managers have relied on a routine application of a microbial subtyping-based source attribution model since 1995. In 2013, multiple locus variable number tandem repeat analysis (MLVA) substituted phage typing as the subtyping method for surveillance of S. Enteritidis and S. Typhimurium isolated from animals, food, and humans in Denmark. The purpose of this study was to develop a modeling approach applying a combination of serovars, MLVA types, and antibiotic resistance profiles for the Salmonella source attribution, and assess the utility of the results for the food safety decisionmakers. Full and simplified MLVA schemes from surveillance data were tested, and model fit and consistency of results were assessed using statistical measures. We conclude that loci schemes STTR5/STTR10/STTR3 for S. Typhimurium and SE9/SE5/SE2/SE1/SE3 for S. Enteritidis can be used in microbial subtyping-based source attribution models. Based on the results, we discuss that an adjustment of the discriminatory level of the subtyping method applied often will be required to fit the purpose of the study and the available data. The issues discussed are also considered highly relevant when applying, e.g., extended multi-locus sequence typing or next-generation sequencing techniques.

  13. Variable mechanical ventilation

    PubMed Central

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini Jr., Luiz Alberto; Friedman, Gilberto

    2017-01-01

    Objective To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Methods Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". Results A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Conclusion Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation. PMID:28444076

  14. Variable mechanical ventilation.

    PubMed

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  15. A Strong Kind of Riemann Integrability

    ERIC Educational Resources Information Center

    Thomson, Brian S.

    2012-01-01

    The usual definition of the Riemann integral as a limit of Riemann sums can be strengthened to demand more of the function to be integrated. This super-Riemann integrability has interesting properties and provides an easy proof of a simple change of variables formula and a novel characterization of derivatives. This theory offers teachers and…

  16. A Strong Kind of Riemann Integrability

    ERIC Educational Resources Information Center

    Thomson, Brian S.

    2012-01-01

    The usual definition of the Riemann integral as a limit of Riemann sums can be strengthened to demand more of the function to be integrated. This super-Riemann integrability has interesting properties and provides an easy proof of a simple change of variables formula and a novel characterization of derivatives. This theory offers teachers and…

  17. Integration, Resegregation and Integration Maintenance.

    ERIC Educational Resources Information Center

    Peterman, William A.

    Recent increases in black migration to the suburbs and the continuing existence of discrimination in housing have emphasized the issues of integration and resegregation in suburban municipalities. To prevent resegregation, many integrated municipalities have adopted integration maintenance measures such as efforts to inform people that racial…

  18. Inherent Variability and the Obligatory Contour Principle.

    ERIC Educational Resources Information Center

    Guy, Gregory R.; Boberg, Charles

    1997-01-01

    Notes that English coronal stop deletion is constrained by the preceding segment, so that stops and sibilants favor deletion more than liquids and nonsibilant fricatives. Suggests the existence of an attractive theoretical integration of categorical and variable processes in the grammar to account for the constraint. (26 references) (Author/CK)

  19. Integrated airframe propulsion control

    NASA Technical Reports Server (NTRS)

    Fennell, R. E.; Black, S. B.

    1982-01-01

    Perturbation equations which describe flight dynamics and engine operation about a given operating point are combined to form an integrated aircraft/propulsion system model. Included in the model are the dependence of aerodynamic coefficients upon atmospheric variables along with the dependence of engine variables upon flight condition and inlet performance. An off-design engine performance model is used to identify interaction parameters in the model. Inclusion of subsystem interaction effects introduces coupling between flight and propulsion variables. To analyze interaction effects on control, consideration is first given to control requirements for separate flight and engine models. For the separate airframe model, feedback control provides substantial improvement in short period damping. For the integrated system, feedback control compensates for the coupling present in the model and provides good overall system stability. However, this feedback control law involves many non-zero gains. Analysis of suboptimal control strategies indicates that performance of the closed loop integrated system can be maintained with a feedback matrix in which the number of non-zero gains is small relative to the number of components in the feedback matrix.

  20. Understanding Brown Dwarf Variability

    NASA Technical Reports Server (NTRS)

    Marley, Mark S.

    2013-01-01

    Surveys of brown dwarf variability continue to find that roughly half of all brown dwarfs are variable. While variability is observed amongst all types of brown dwarfs, amplitudes are typically greatest for L-T transition objects. In my talk I will discuss the possible physical mechanisms that are responsible for the observed variability. I will particularly focus on comparing and contrasting the effects of changes in atmospheric thermal profile and cloud opacity. The two different mechanisms will produce different variability signatures and I will discuss the extent to which the current datasets constrain both mechanisms. By combining constraints from studies of variability with existing spectral and photometric datasets we can begin to construct and test self-consistent models of brown dwarf atmospheres. These models not only aid in the interpretation of existing objects but also inform studies of directly imaged giant planets.

  1. VARIABLE TIME DELAY MEANS

    DOEpatents

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  2. Variability-selected AGN

    NASA Astrophysics Data System (ADS)

    De Marco, Barbara

    2016-08-01

    Variability is one of the defining properties of active galactic nuclei (AGN) as a class. Significant flux variations are observed in different wavebands and over a wide range of time scales, from hours to years. I will review our current knowledge of AGN variability, in particular discussing interband correlations, scaling relationships, and models for the origin of the observed flux variations. I will then focus on variability as a survey technique, discussing strategies to use variability as an independent tool for selecting AGN candidates for spectroscopic follow-up.

  3. CAM - Geometric systems integration

    NASA Astrophysics Data System (ADS)

    Dunlap, G. C.

    The integration of geometric and nongeometric information for efficient use of CAM is examined. Requirements for engineering drawings requested by management are noted to involve large volumes of nongeometric data to define the materials and quantity variables which impinge on the required design, so that the actual design may be the last and smaller step in the CAM process. Geometric classification and coding are noted to offer an alpha/numeric identifier for integrating the engineering design, manufacturing, and quality assurance functions. An example is provided of a turbine gear part coding in terms of polycode and monocode displays, showing a possible covering of more than 10 trillion features. Software is stressed as the key to integration of company-wide data.

  4. Chromospheric variability of M giant semiregular variables

    NASA Astrophysics Data System (ADS)

    Eaton, Joel A.; Johnson, Hollis R.; Cadmus, Robert R., Jr.

    1990-11-01

    The results of monitoring the chromospheric emission from three M giant semiregular variables, W Cyg, NU Pav, and Theta Aps at low dispersion with the IUE satellite are reported along with high-dispersion IUE spectra for R Lyr and Delta(2) Lyr. The chromospheric emission is variable in all of the first three stars, and the Mg II strength generally follows changes in the continuum. However, the changes are not directly proportional, and there is a phase lag between the emission in the continuum and that in the Mg II lines, at least in W Cyg and probably in NU Pav. R Lyr showed changes in Mg II lines strengths and profiles uncorrelated with Al II 2669 A strength or with the strengths of fluorescent Fe I lines. The chromospheres of all these stars are clearly modified by stellar pulsation. The position and extent of the emitting layers of the chromospheres of the stars are estimated.

  5. Stochastic modeling of interannual variation of hydrologic variables

    NASA Astrophysics Data System (ADS)

    Dralle, David; Karst, Nathaniel; Müller, Marc; Vico, Giulia; Thompson, Sally E.

    2017-07-01

    Quantifying the interannual variability of hydrologic variables (such as annual flow volumes, and solute or sediment loads) is a central challenge in hydrologic modeling. Annual or seasonal hydrologic variables are themselves the integral of instantaneous variations and can be well approximated as an aggregate sum of the daily variable. Process-based, probabilistic techniques are available to describe the stochastic structure of daily flow, yet estimating interannual variations in the corresponding aggregated variable requires consideration of the autocorrelation structure of the flow time series. Here we present a method based on a probabilistic streamflow description to obtain the interannual variability of flow-derived variables. The results provide insight into the mechanistic genesis of interannual variability of hydrologic processes. Such clarification can assist in the characterization of ecosystem risk and uncertainty in water resources management. We demonstrate two applications, one quantifying seasonal flow variability and the other quantifying net suspended sediment export.

  6. (1+1)-dimensional separation of variables

    NASA Astrophysics Data System (ADS)

    Pucacco, Giuseppe; Rosquist, Kjell

    2007-11-01

    In this paper we explore general conditions which guarantee that the geodesic flow on a two-dimensional manifold with indefinite signature is locally separable. This is equivalent to showing that a two-dimensional natural Hamiltonian system on the hyperbolic plane possesses a second integral of motion which is a quadratic polynomial in the momenta associated with a secind rank Killing tensor. We examine the possibility that the integral is preserved by the Hamiltonian flow on a given energy hypersurface only (weak integrability) and derive the additional requirement necessary to have conservation at arbitrary values of the Hamiltonian (strong integrability). Using null coordinates, we show that the leading-order coefficients of the invariant are arbitrary functions of one variable in the case of weak integrability. These functions are quadratic polynomials in the coordinates in the case of strong integrability. We show that for (1+1)-dimensional systems, there are three possible types of conformal Killing tensors and, therefore, three distinct separability structures in contrast to the single standard Hamilton-Jacobi-type separation in the positive definite case. One of the new separability structures is the complex/harmonic type which is characterized by complex separation variables. The other new type is the linear/null separation which occurs when the conformal Killing tensor has a null eigenvector.

  7. Variable volume combustor

    DOEpatents

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  8. A variety of variables.

    PubMed

    Jupiter, Daniel C

    2014-01-01

    In designing studies and developing plans for analyses, we must consider which tests are appropriate for the types of variables we are using. Here I describe the types of variables available to us, and I briefly consider the appropriate tools to use in their analysis. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Variable Density Tunnel

    NASA Technical Reports Server (NTRS)

    1931-01-01

    Variable Density Tunnel in operation. Man at far right is probably Harold J. 'Cannonball' Tuner, longtime safety officer, who started with Curtiss in the teens. This view of the Variable Density Tunnel clearly shows the layout of the Tunnel's surroundings, as well as the plumbing and power needs of the this innovative research tool.

  10. Reinforcing Saccadic Amplitude Variability

    ERIC Educational Resources Information Center

    Paeye, Celine; Madelain, Laurent

    2011-01-01

    Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we…

  11. Tropical Pacific moisture variability

    NASA Technical Reports Server (NTRS)

    Mcguirk, James P.

    1989-01-01

    Research objectives are to: (1) describe the synoptic scale variability of moisture over the tropical Pacific Ocean; (2) describe the systems leading to this variability; and (3) develop and implement satellite analysis procedures to facilitate (1) and (2) over the data sparse Pacific.

  12. POVMs and hidden variables

    NASA Astrophysics Data System (ADS)

    Stairs, Allen

    2007-06-01

    Recent results by Paul Busch and Adán Cabello claim to show that by appealing to POVMs, non-contextual hidden variables can be ruled out in two dimensions. While the results of Busch and Cabello are mathematically correct, interpretive problems render them problematic as no hidden variable proofs.

  13. Basic properties and variability

    NASA Technical Reports Server (NTRS)

    Querci, Francois R.

    1987-01-01

    Giant and supergiant M, S, and C stars are discussed in this survey of research. Basic properties as determined by spectra, chemical composition, photometry, or variability type are discussed. Space motions and space distributions of cool giants are described. Distribution of these stars in our galaxy and those nearby is discussed. Mira variables in particular are surveyed with emphasis on the following topics: (1) phase lag phenomenon; (2) Mira light curves; (3) variations in color indices; (4) determination of multiple periods; (5) correlations between quantities such as period length, light-curve shape, infrared (IR) excess, and visible and IR color diagram; (6) semiregular (SR) variables and different time scales in SR light variations; (7) irregular variable Lb and Lc stars; (8) different time-scale light variations; (9) hydrogen-deficient carbon (HdC) stars, in particular RCB stars; and (10) irreversible changes and rapid evolution in red variable stars.

  14. Variable speed drive

    NASA Technical Reports Server (NTRS)

    Obler, H. D. (Inventor)

    1983-01-01

    A variable speed drive wherein a first embodiment is comprised of a pivotally mounted prime mover coupled to a rotary fluid output device, such as a fan or pump, through a variable and fixed pulley drive arrangement is described. The pivotal position of the prime mover and accordingly the pitch diameter of variable pulley means is controlled in accordance with fluid motor means coupled to the prime mover. This is actuated in response to a fluid feedback control signal derived from a sensed output of the rotary fluid output device. The pivotal motion of the prime mover imparts an arcuate motion to the variable pulley means which effects a speed variation of the rotary fluid output device in accordance with the variation of the pitch diameter ratio of opposing variable and fixed pulley means.

  15. Integrated Learning

    ERIC Educational Resources Information Center

    Gnanakan, Ken

    2012-01-01

    This book upholds the idea of learning and education as a means to individual development and social empowerment. It presents a holistic picture, looking at learning as an integral part of one's social and physical life. Strongly differing from existing classroom perspectives, the book analyses integrated learning at its broadest possible…

  16. Integrated Networks.

    ERIC Educational Resources Information Center

    Robinovitz, Stewart

    1987-01-01

    A strategy for integrated data and voice networks implemented at the University of Michigan is described. These networks often use multi-technologies, multi-vendors, and multi-transmission media that will be fused into a single integrated network. Transmission media include twisted-pair wire, coaxial cable, fiber optics, and microwave. (Author/MLW)

  17. Integrated Learning

    ERIC Educational Resources Information Center

    Gnanakan, Ken

    2012-01-01

    This book upholds the idea of learning and education as a means to individual development and social empowerment. It presents a holistic picture, looking at learning as an integral part of one's social and physical life. Strongly differing from existing classroom perspectives, the book analyses integrated learning at its broadest possible…

  18. Integrated Science.

    ERIC Educational Resources Information Center

    Rainey, Larry; Miller, Roxanne Greitz

    1997-01-01

    Describes the Integrated Science program that integrates biology, earth/space science, chemistry, and physics over a three-year, spiraling sequence arranged around broad themes such as cycles, changes, patterns, and waves. Includes weekly telecasts via public television and satellite, teacher manuals, student handbooks, e-mail connections, staff…

  19. Integrative Education.

    ERIC Educational Resources Information Center

    Walker, Dean

    1995-01-01

    In contrast with subject-bound education, integrative education promotes the construction of broad "mental programs" that require students to use skills and information in new, realistic contexts. Early childhood education has long been a model of integrative education, emphasizing the whole child and offering a wide range of experiences that…

  20. Integrated Networks.

    ERIC Educational Resources Information Center

    Robinovitz, Stewart

    1987-01-01

    A strategy for integrated data and voice networks implemented at the University of Michigan is described. These networks often use multi-technologies, multi-vendors, and multi-transmission media that will be fused into a single integrated network. Transmission media include twisted-pair wire, coaxial cable, fiber optics, and microwave. (Author/MLW)

  1. Integrated care requires integrated supervision

    PubMed Central

    Ketelaars, Corry A.J

    2011-01-01

    Introduction Given recent developments in integrated care, it is becoming increasingly important for the Dutch Health Care Inspectorate to direct its supervision in a way that may help speed up the implementation of integrated care. Description of care practice Since the implementation of integrated care for chronic patients is facing obstacles, alternative methods are required to ensure that the implementation process does not run into any delays. By applying a risk-based approach to integrated care providers, the Inspectorate can analyse the care providers' performance by means of quality indicators and rank them. In order to be effective, appropriated supervision arrangements will be applied to the care providers of integrated care. Discussion With a ranking model transparency will be improved and this may encourage integrated care providers to strive for greater quality due to the competition inherent in the system. Supervision based on advice and encouragement might be helpful in the implementation of integrated care. Conclusion Integrated care also requires integrated supervision, which means the Inspectorate may have to reconsider its working methods and the composition of its inspection teams. PMID:21637707

  2. Mars dust storms - Interannual variability and chaos

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.; Lyons, James R.

    1993-01-01

    The hypothesis is that the global climate system, consisting of atmospheric dust interacting with the circulation, produces its own interannual variability when forced at the annual frequency. The model has two time-dependent variables representing the amount of atmospheric dust in the northern and southern hemispheres, respectively. Absorption of sunlight by the dust drives a cross-equatorial Hadley cell that brings more dust into the heated hemisphere. The circulation decays when the dust storm covers the globe. Interannual variability manifests itself either as a periodic solution in which the period is a multiple of the Martian year, or as an aperiodic (chaotic) solution that never repeats. Both kinds of solution are found in the model, lending support to the idea that interannual variability is an intrinsic property of the global climate system. The next step is to develop a hierarchy of dust-circulation models capable of being integrated for many years.

  3. PV output variability modeling using satellite imagery.

    SciTech Connect

    Stein, Joshua S.; Ellis, Abraham; Reno, Matthew J.

    2010-11-01

    High frequency irradiance variability measured on the ground is caused by the formation, dissipation, and passage of clouds in the sky. If we can identify and associate different cloud types/patterns from satellite imagery, we may be able to predict irradiance variability in areas lacking sensors. With satellite imagery covering the entire U.S., this allows for more accurate integration planning and power flow modeling over wide areas. Satellite imagery from southern Nevada was analyzed at 15 minute intervals over a year. Methods for image stabilization, cloud detection, and textural classification of clouds were developed and tested. High Performance Computing parallel processing algorithms were also investigated and tested. Artificial Neural Networks using imagery as inputs were trained on ground-based measurements of irradiance to model the variability and were tested to show some promise as a means for predicting irradiance variability.

  4. Mars dust storms - Interannual variability and chaos

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.; Lyons, James R.

    1993-01-01

    The hypothesis is that the global climate system, consisting of atmospheric dust interacting with the circulation, produces its own interannual variability when forced at the annual frequency. The model has two time-dependent variables representing the amount of atmospheric dust in the northern and southern hemispheres, respectively. Absorption of sunlight by the dust drives a cross-equatorial Hadley cell that brings more dust into the heated hemisphere. The circulation decays when the dust storm covers the globe. Interannual variability manifests itself either as a periodic solution in which the period is a multiple of the Martian year, or as an aperiodic (chaotic) solution that never repeats. Both kinds of solution are found in the model, lending support to the idea that interannual variability is an intrinsic property of the global climate system. The next step is to develop a hierarchy of dust-circulation models capable of being integrated for many years.

  5. Integrative psychotherapy.

    PubMed

    Kozarić-Kovacić, Dragica

    2008-09-01

    The main purposes of the article are to present the history of integration in psychotherapy, the reasons of the development integrative approaches, and the approaches to integration in psychotherapy. Three approaches to integration in psychotherapy exist: theoretical integration, theoretical eclecticism, and common factors in different psychotherapeutic trends. In integrative psychotherapy, the basic epistemology, theory, and clinical practice are based on the phenomenology, field theory, holism, dialogue, and co-creation of dialogue in the therapeutic relationship. The main criticism is that integrative psychotherapy suffers from confusion and many unresolved controversies. It is difficult to theoretically and methodologically define the clinically applied model that is based on such a different epistemological and theoretical presumptions. Integrative psychotherapy is a synthesis of humanistic psychotherapy, object relations theory, and psychoanalytical self psychology. It focuses on the dynamics and potentials of human relationships, with a goal of changing the relations and understanding internal and external resistances. The process of integrative psychotherapy is primarily focused on the developmental-relational model and co-creation of psychotherapeutic relationship as a single interactive event, which is not unilateral, but rather a joint endeavor by both the therapist and the patient/client. The need for a relationship is an important human need and represents a process of attunement that occurs as a response to the need for a relationship, a unique interpersonal contact between two people. If this need is not met, it manifests with the different feelings and various defenses. To meet this need, we need to have another person with whom we can establish a sensitive, attuned relationship. Thus, the therapist becomes this person who tries to supplement what the person did not receive. Neuroscience can be a source of integration through different therapies. We

  6. Variability study for saltstone

    SciTech Connect

    Harbour, J. R.; Edwards, T. B.; Hansen, E. K.; Williams, V. J.

    2005-10-01

    This report is a summary of the bench-scale experimental studies performed by the Savannah River National Laboratory (SRNL) for Waste Solidification Engineering (WSE) to establish the viability of a grout-based variability study. In order for a variability study to be useful, the property measurements of the fresh and cured Saltstone must be reproducible with an inherent variation that is small compared to the changes in the properties measured over the expected range of variability for a Salt Batch. This scoping task addressed the issue of reproducibility for Saltstone.

  7. Variable geometry trusses

    NASA Technical Reports Server (NTRS)

    Robertshaw, H. H.; Reinholtz, C. F.

    1989-01-01

    Vibration control and kinematic control with variable-geometry trusses are covered. The analytical approach taken is to model each actuator with lumped masses and model a beam with finite elements, including in each model the generalized reaction forces from the beam on the actuator or vice versa. It is concluded that, from an operational standpoint, the variable-geometry truss actuator is more favorable than the inertia-type actuator. A spatial variable-geometry truss is used to test out rudimentary robotic tasks.

  8. Magnetically Controlled Variable Transformer

    NASA Technical Reports Server (NTRS)

    Kleiner, Charles T.

    1994-01-01

    Improved variable-transformer circuit, output voltage and current of which controlled by use of relatively small current supplied at relatively low power to control windings on its magnetic cores. Transformer circuits of this type called "magnetic amplifiers" because ratio between controlled output power and power driving control current of such circuit large. This ratio - power gain - can be as large as 100 in present circuit. Variable-transformer circuit offers advantages of efficiency, safety, and controllability over some prior variable-transformer circuits.

  9. Scholarly Integrity.

    PubMed

    Francisco, Joseph S; Hahn, Ulrike; Schwarz, Helmut

    2017-04-03

    "… Scholarly integrity is not only the foundational bedrock of scientific inquiry, it is also the prerequisite for a positive image of scholarship … For individuals, integrity is an aspect of moral character and experience. For institutions, it is about creating an environment that promotes responsible conduct … In the first instance, research institutions must provide guidelines and codes of practice on scholarly integrity …" Read more in the Editorial by J. S. Francisco, U. Hahn, and H. Schwarz. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Understanding Biomass Feedstock Variability

    SciTech Connect

    Kevin L. Kenney; Garold L. Gresham; William A. Smith; Tyler L. Westover

    2013-01-01

    If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per-ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that, due to inherent species variabilities, production conditions and differing harvest, collection and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

  11. Variable pitch propeller

    NASA Technical Reports Server (NTRS)

    Pistolesi, Enrico

    1923-01-01

    The advantages of variable pitch propellers over constant pitch propellers is presented along with different methods of varying the pitch. The technique of varying the shape of the propeller is presented as the most efficient one.

  12. Understanding Biomass Feedstock Variability

    SciTech Connect

    Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

    2013-01-01

    If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

  13. Solar variability datalogger

    SciTech Connect

    Lave, Matthew; Stein, Joshua; Smith, Ryan

    2016-07-28

    To address the lack of knowledge of local solar variability, we have developed and deployed a low-cost solar variability datalogger (SVD). While most currently used solar irradiance sensors are expensive pyranometers with high accuracy (relevant for annual energy estimates), low-cost sensors display similar precision (relevant for solar variability) as high-cost pyranometers, even if they are not as accurate. In this work, we present evaluation of various low-cost irradiance sensor types, describe the SVD, and present validation and comparison of the SVD collected data. In conclusion, the low cost and ease of use of the SVD will enable a greater understanding of local solar variability, which will reduce developer and utility uncertainty about the impact of solar photovoltaic (PV) installations and thus will encourage greater penetrations of solar energy.

  14. Solar variability datalogger

    DOE PAGES

    Lave, Matthew; Stein, Joshua; Smith, Ryan

    2016-07-28

    To address the lack of knowledge of local solar variability, we have developed and deployed a low-cost solar variability datalogger (SVD). While most currently used solar irradiance sensors are expensive pyranometers with high accuracy (relevant for annual energy estimates), low-cost sensors display similar precision (relevant for solar variability) as high-cost pyranometers, even if they are not as accurate. In this work, we present evaluation of various low-cost irradiance sensor types, describe the SVD, and present validation and comparison of the SVD collected data. In conclusion, the low cost and ease of use of the SVD will enable a greater understandingmore » of local solar variability, which will reduce developer and utility uncertainty about the impact of solar photovoltaic (PV) installations and thus will encourage greater penetrations of solar energy.« less

  15. Solar variability datalogger

    SciTech Connect

    Lave, Matthew; Stein, Joshua; Smith, Ryan

    2016-07-28

    To address the lack of knowledge of local solar variability, we have developed and deployed a low-cost solar variability datalogger (SVD). While most currently used solar irradiance sensors are expensive pyranometers with high accuracy (relevant for annual energy estimates), low-cost sensors display similar precision (relevant for solar variability) as high-cost pyranometers, even if they are not as accurate. In this work, we present evaluation of various low-cost irradiance sensor types, describe the SVD, and present validation and comparison of the SVD collected data. In conclusion, the low cost and ease of use of the SVD will enable a greater understanding of local solar variability, which will reduce developer and utility uncertainty about the impact of solar photovoltaic (PV) installations and thus will encourage greater penetrations of solar energy.

  16. Discovery of variable stars

    NASA Technical Reports Server (NTRS)

    Kurochkin, N. Y.

    1973-01-01

    Instrumented methods of discovering variable stars are reviewed, specifically the blink comparator, color contrast method, positive-negative method, and television method. Among the empirical methods discussed, the Van Gent method is the most important.

  17. Littlewood-Paley operators on Morrey spaces with variable exponent.

    PubMed

    Tao, Shuangping; Wang, Lijuan

    2014-01-01

    By applying the vector-valued inequalities for the Littlewood-Paley operators and their commutators on Lebesgue spaces with variable exponent, the boundedness of the Littlewood-Paley operators, including the Lusin area integrals, the Littlewood-Paley g-functions and g μ *-functions, and their commutators generated by BMO functions, is obtained on the Morrey spaces with variable exponent.

  18. Integrated research in constitutive modelling at elevated temperatures, part 1

    NASA Technical Reports Server (NTRS)

    Haisler, W. E.; Allen, D. H.

    1986-01-01

    Topics covered include: numerical integration techniques; thermodynamics and internal state variables; experimental lab development; comparison of models at room temperature; comparison of models at elevated temperature; and integrated software development.

  19. Defining Integrals Over Connections in the Discretized Gravitational Functional Integrals

    NASA Astrophysics Data System (ADS)

    Khatsymovsky, V. M.

    Integration over connection type variables in the path integral for the discrete form of the first-order formulation of general relativity theory is studied. The result (a generalized function of the rest of variables of the type of tetrad or elementary areas) can be defined through its moments, i.e. integrals of it with the area tensor monomials. In our previous paper these moments have been defined by deforming integration contours in the complex plane as if we had passed to a Euclidean-like region. In this paper we define and evaluate the moments in the genuine Minkowski region. The distribution of interest resulting from these moments in this non-positively defined region contains the divergences. We prove that the latter contribute only to the singular (δ-function like) part of this distribution with support in the non-physical region of the complex plane of area tensors while in the physical region this distribution (usual function) confirms that defined in our previous paper which decays exponentially at large areas. Besides that, we evaluate the basic integrals over which the integral over connections in the general path integral can be expanded.

  20. Variable contour securing system

    NASA Technical Reports Server (NTRS)

    Zebus, P. P.; Packer, P. N.; Haynie, C. C. (Inventor)

    1978-01-01

    A variable contour securing system has a retaining structure for a member whose surface contains a variable contour. The retaining mechanism includes a spaced array of adjustable spindles mounted on a housing. Each spindle has a base member support cup at one end. A vacuum source is applied to the cups for seating the member adjacent to the cups. A locking mechanism sets the spindles in a predetermined position once the member has been secured to the spindle support cups.

  1. VARIABLE-THROW CAM

    DOEpatents

    Godsil, E.C.; Robinson, E.Y.

    1963-07-16

    A variable-throw cam comprising inner and outer eccentric sleeves which are adjustably locked together is described. The cam throw is varied by unlocking the inner and outer sleeves, rotating the outer sleeve relative to the inner one until the desired throw is obtained, and locking the sleeves together again. The cam is useful in applications wherein a continuously-variable throw is required, e.g., ram-and-die pressing operations, cyclic fatigue testing of materials, etc. (AEC)

  2. Integrative Oncology.

    PubMed

    Lopez, Gabriel; Mao, Jun J; Cohen, Lorenzo

    2017-09-01

    Integrative oncology helps support the health of patients with cancer and their caregivers through an evidence-informed approach to lifestyle and behavior modification and the use of complementary health therapies as part of conventional cancer care. Integrative approaches can provide patients relief from cancer and cancer treatment-related symptoms, leading to improvements in their physical and psychosocial health. An evidence-informed approach is important when recommending an integrative cancer plan. Efforts at enhancing communication between patients and health care providers, as well as between integrative practitioners and conventional health care teams, are critical to achieving optimal health and healing for patients with cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Integrated diagnostics

    NASA Technical Reports Server (NTRS)

    Hunthausen, Roger J.

    1988-01-01

    Recently completed projects in which advanced diagnostic concepts were explored and/or demonstrated are summarized. The projects begin with the design of integrated diagnostics for the Army's new gas turbine engines, and advance to the application of integrated diagnostics to other aircraft subsystems. Finally, a recent project is discussed which ties together subsystem fault monitoring and diagnostics with a more complete picture of flight domain knowledge.

  4. Microelectrofluidic iris for variable aperture

    NASA Astrophysics Data System (ADS)

    Chang, Jong-hyeon; Jung, Kyu-Dong; Lee, Eunsung; Choi, Minseog; Lee, Seungwan

    2012-03-01

    This paper presents a variable aperture design based on the microelectrofluidic technology which integrates electrowetting and microfluidics. The proposed microelectrofluidic iris (MEFI) consists of two immiscible fluids and two connected surface channels formed by three transparent plates and two spacers between them. In the initial state, the confined aqueous ring makes two fluidic interfaces, on which the Laplace pressure is same, in the hydrophobic surface channels. When a certain voltage is applied between the dielectric-coated control electrode beneath the three-phase contact line (TCL) and the reference electrode for grounding the aqueous, the contact angle changes on the activated control electrode. At high voltage over the threshold, the induced positive pressure difference makes the TCLs on the 1st channel advance to the center and the aperture narrow. If there is no potential difference between the control and reference electrodes, the pressure difference becomes negative. It makes the TCLs on the 1st channel recede and the aperture widen to the initial state. It is expected that the proposed MEFI is able to be widely used because of its fast response, circular aperture, digital operation, high aperture ratio, and possibility to be miniaturized for variable aperture.

  5. Electronically Variable Pressure Regulator (EVPR)

    NASA Technical Reports Server (NTRS)

    Reinicke, R. H.; Nelson, R. O.; Hurlbert, E.

    1989-01-01

    A new programmable electronically variable pressure regulator (EVPR) concept accurately controls the local outlet or remote system pressure. It uses an integral pulse width modulated rare earth permanent magnet motor operating in response to redundant pressure transducer feedback signals. The EVPR is a simple single stage device that does not use dynamic seals or pilot valving. Conversion of partial revolution motor torque to poppet lifting force is accomplished by pure flexure action to avoid using bearings. The flexure drive (called the ROTAX) has a variable lead to minimize motor weight and power consumption. Breadboard tests were completed successfully on two critical design elements of the EVPR: the ROTAX and the motor. The ROTAX cable system was tested for 250,000 cycles without failure. The breadboard motor met the basic design requirements including the design torque and power consumption. Prototype parts were fabricated, and testing of the prototype EVPR has started. It is PC computer controlled to facilitate programming, data acquisition and analysis. A lightweight dedicated microprocessor is planned for the flightweight EVPR.

  6. Electronically Variable Pressure Regulator (EVPR)

    NASA Astrophysics Data System (ADS)

    Reinicke, R. H.; Nelson, R. O.; Hurlbert, E.

    1989-05-01

    A new programmable electronically variable pressure regulator (EVPR) concept accurately controls the local outlet or remote system pressure. It uses an integral pulse width modulated rare earth permanent magnet motor operating in response to redundant pressure transducer feedback signals. The EVPR is a simple single stage device that does not use dynamic seals or pilot valving. Conversion of partial revolution motor torque to poppet lifting force is accomplished by pure flexure action to avoid using bearings. The flexure drive (called the ROTAX) has a variable lead to minimize motor weight and power consumption. Breadboard tests were completed successfully on two critical design elements of the EVPR: the ROTAX and the motor. The ROTAX cable system was tested for 250,000 cycles without failure. The breadboard motor met the basic design requirements including the design torque and power consumption. Prototype parts were fabricated, and testing of the prototype EVPR has started. It is PC computer controlled to facilitate programming, data acquisition and analysis. A lightweight dedicated microprocessor is planned for the flightweight EVPR.

  7. Feedback Integrators

    NASA Astrophysics Data System (ADS)

    Chang, Dong Eui; Jiménez, Fernando; Perlmutter, Matthew

    2016-12-01

    A new method is proposed to numerically integrate a dynamical system on a manifold such that the trajectory stably remains on the manifold and preserves the first integrals of the system. The idea is that given an initial point in the manifold we extend the dynamics from the manifold to its ambient Euclidean space and then modify the dynamics outside the intersection of the manifold and the level sets of the first integrals containing the initial point such that the intersection becomes a unique local attractor of the resultant dynamics. While the modified dynamics theoretically produces the same trajectory as the original dynamics, it yields a numerical trajectory that stably remains on the manifold and preserves the first integrals. The big merit of our method is that the modified dynamics can be integrated with any ordinary numerical integrator such as Euler or Runge-Kutta. We illustrate this method by applying it to three famous problems: the free rigid body, the Kepler problem and a perturbed Kepler problem with rotational symmetry. We also carry out simulation studies to demonstrate the excellence of our method and make comparisons with the standard projection method, a splitting method and Störmer-Verlet schemes.

  8. Variable Time Base Integrator Circuit for Buffet Signal Measurements

    NASA Technical Reports Server (NTRS)

    Batts, Colossie N.

    1973-01-01

    A measurement circuit to obtain buffet data from wind tunnel models wherein a signal proportional to the average RMS value of buffet data is produced for subsequent recording. Feedback means are employed to suppress the D.C. portion of signals developed by the strain gages during dynamic testing. Automatic recording of gain settings of amplifiers employed in the circuit is also provided.

  9. 75 FR 4316 - Integration of Variable Energy Resources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Information), Office of Energy Policy and Innovations, Federal Energy Regulatory Commission, 888 First Street..., including the use of accurate forecasting tools; (2) scheduling practices, flexibility, and incentives for... responses to the specific questions listed below. A. Data and Forecasting 14. The scheduling and...

  10. Modeling variability and scale integration of LAI measurements

    Treesearch

    Kris Nackaerts; Pol Coppin

    2000-01-01

    Rapid and reliable estimation of leaf area at various scales is important for research on chance detection of leaf area index (LAI) as an indicator of ecosystem condition. It is of utmost importance to know to what extent boundary and illumination conditions, data aggregation method, and sampling scheme influence the relative accuracy of stand-level LAI measurements....

  11. The Earth's variable Chandler wobble

    NASA Astrophysics Data System (ADS)

    Bizouard, C.; Remus, F.; Lambert, S. B.; Seoane, L.; Gambis, D.

    2011-02-01

    Aims: We investigated the causes of the Earth's Chandler wobble variability over the past 60 years. Our approach is based on integrating of the atmospheric and oceanic angular momentum computed by global circulation models. We directly compared the result of the integration with the Earth's pole coordinate observed by precise astrometric, space, and geodetic techniques. This approach differs from the traditional approach in which the observed polar motion is transformed into a so-called geodetic excitation function, and compared afterwards with the angular momentum of the external geophysical fluid layers. Methods: In the time domain, we integrated the atmospheric angular momentum time series from the National Center for Environmental Prediction/National Center for Atmospheric Research Reanalysis project and the oceanic angular momentum data from the ECCO consortium. We extracted the Chandler wobble from this modeled polar motion by singular spectrum analysis, and compared it with the Chandler wobble extracted from the observed polar motion given by the International Earth Rotation and Reference Systems Service data. Results: We showed that the combination of the atmosphere and the oceans explains most of the observed Chandler wobble variations, and is consistent with results reported in the literature and obtained with the traditional approach. Our approach allows one to appreciate the separate contributions of the atmosphere and the oceans to the various bumps and valleys observed in the Chandler wobble. Though the atmosphere explains the Chandler wobble amplitude variations between 1949 and 1970, the reexcitation of the Chandler wobble that begins in the 1980s, after a minimum around 1970, and that reaches its maximum in the late 1990s is due to the oceans, while the atmospheric contribution remains stable within the same period.

  12. Classifying TDSS Stellar Variables

    NASA Astrophysics Data System (ADS)

    Amaro, Rachael Christina; Green, Paul J.; TDSS Collaboration

    2017-01-01

    The Time Domain Spectroscopic Survey (TDSS), a subprogram of SDSS-IV eBOSS, obtains classification/discovery spectra of point-source photometric variables selected from PanSTARRS and SDSS multi-color light curves regardless of object color or lightcurve shape. Tens of thousands of TDSS spectra are already available and have been spectroscopically classified both via pipeline and by visual inspection. About half of these spectra are quasars, half are stars. Our goal is to classify the stars with their correct variability types. We do this by acquiring public multi-epoch light curves for brighter stars (r<19.5mag) from the Catalina Sky Survey (CSS). We then run a number of light curve analyses from VARTOOLS, a program for analyzing astronomical time-series data, to constrain variable type both for broad statistics relevant to future surveys like the Transiting Exoplanet Survey Satellite (TESS) and the Large Synoptic Survey Telescope (LSST), and to find the inevitable exotic oddballs that warrant further follow-up. Specifically, the Lomb-Scargle Periodogram and the Box-Least Squares Method are being implemented and tested against their known variable classifications and parameters in the Catalina Surveys Periodic Variable Star Catalog. Variable star classifications include RR Lyr, close eclipsing binaries, CVs, pulsating white dwarfs, and other exotic systems. The key difference between our catalog and others is that along with the light curves, we will be using TDSS spectra to help in the classification of variable type, as spectra are rich with information allowing estimation of physical parameters like temperature, metallicity, gravity, etc. This work was supported by the SDSS Research Experience for Undergraduates program, which is funded by a grant from Sloan Foundation to the Astrophysical Research Consortium.

  13. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

    Mosher, Michael; Lewis, John F.; Campbell, Melissa

    2012-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multiple suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development of the suit loop regulator for Orion.

  14. Improved Nystrom Integrators

    NASA Technical Reports Server (NTRS)

    Lear, William M.

    1993-01-01

    New formulation for Nystrom integrators offers increased precision and speed of computation. Formulation takes advantage of capabilities of modern electronic computers. Independent and dependent variables and various partial and total derivatives expressed via compact tensor notation. In this approach, typical set of constraint equations derived in about 1 day. Solution of constraint equations speeded by SEARCH computer program. Is general-purpose optimization program, which maximizes or minimizes cost function defined by user. Used successfully, to make least-squares fit of about 4,000 equations in 12 unknowns.

  15. Variable stator radial turbine

    NASA Technical Reports Server (NTRS)

    Rogo, C.; Hajek, T.; Chen, A. G.

    1984-01-01

    A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

  16. Gaia and Variable Stars

    NASA Astrophysics Data System (ADS)

    Udalski, A.; Soszyński, I.; Skowron, D. M.; Skowron, J.; Pietrukowicz, P.; Mróz, P.; Poleski, R.; Szymański, M. K.; Kozłowski, S.; Wyrzykowski, Ł.; Ulaczyk, K.; Pawlak, M.

    2016-12-01

    We present a comparison of the Gaia DR1 samples of pulsating variable stars - Cepheids and RR Lyr type - with the OGLE Collection of Variable Stars aiming at the characterization of the Gaia mission performance in the stellar variability domain. Out of 575 Cepheids and 2322 RR Lyr candidates from the Gaia DR1 samples located in the OGLE footprint in the sky, 559 Cepheids and 2302 RR Lyr stars are genuine pulsators of these types. The number of misclassified stars is low indicating reliable performance of the Gaia data pipeline. The completeness of the Gaia DR1 samples of Cepheids and RR Lyr stars is at the level of 60-75% as compared to the OGLE Collection dataset. This level of completeness is moderate and may limit the applicability of the Gaia data in many projects.

  17. Integrated flood management.

    PubMed

    Grabs, W; Tyagi, A C; Hyodo, M

    2007-01-01

    While there have been a number of international initiatives centred around hydrological sciences and technical approaches, the social, economic, environmental, and legal and institutional aspects of flood management have been dealt with sporadically and in a limited manner. WMO and the Global Water Partnership have established the Associated Programme on Flood Management (APFM) to address these issues and developed a concept of Integrated Flood Management (IFM) in 2002. This article is the result of the integrated flood management approaches through pilot projects and multi-disciplinary approaches launched by the initiative since the establishment of the IFM concept. This approach seeks to integrate land- and water-resources development in a river basin, within the context of Integrated Water Resources Management (IWRM) and aims at maximizing the benefits from floodplains and at the same time reducing loss of life from flooding. This approach identified the key elements of IFM and recommended that these can be put in place by: adopting a basin approach to flood management; adopting a multi-disciplinary approach in flood management; reducing vulnerability to and risks from flooding; enabling community participation; and preserving ecosystems; and addressing climate change and variability, supported by enabling mechanism through appropriate legislation and regulations.

  18. Variable Lifting Index (VLI)

    PubMed Central

    Waters, Thomas; Occhipinti, Enrico; Colombini, Daniela; Alvarez-Casado, Enrique; Fox, Robert

    2015-01-01

    Objective: We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI). Background: There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks. Method: In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI. Results: The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed. Conclusions: The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated. Application: The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift. PMID:26646300

  19. Terrestrial Carbon Cycle Variability.

    PubMed

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y (-1)) with respect to a large and uncertain background (123 +/- 4 Pg-C y (-1)), and

  20. Terrestrial Carbon Cycle Variability

    PubMed Central

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1), and

  1. The Integrated Hazard Analysis Integrator

    NASA Technical Reports Server (NTRS)

    Morris, A. Terry; Massie, Michael J.

    2009-01-01

    Hazard analysis addresses hazards that arise in the design, development, manufacturing, construction, facilities, transportation, operations and disposal activities associated with hardware, software, maintenance, operations and environments. An integrated hazard is an event or condition that is caused by or controlled by multiple systems, elements, or subsystems. Integrated hazard analysis (IHA) is especially daunting and ambitious for large, complex systems such as NASA s Constellation program which incorporates program, systems and element components that impact others (International Space Station, public, International Partners, etc.). An appropriate IHA should identify all hazards, causes, controls and verifications used to mitigate the risk of catastrophic loss of crew, vehicle and/or mission. Unfortunately, in the current age of increased technology dependence, there is the tendency to sometimes overlook the necessary and sufficient qualifications of the integrator, that is, the person/team that identifies the parts, analyzes the architectural structure, aligns the analysis with the program plan and then communicates/coordinates with large and small components, each contributing necessary hardware, software and/or information to prevent catastrophic loss. As viewed from both Challenger and Columbia accidents, lack of appropriate communication, management errors and lack of resources dedicated to safety were cited as major contributors to these fatalities. From the accident reports, it would appear that the organizational impact of managers, integrators and safety personnel contributes more significantly to mission success and mission failure than purely technological components. If this is so, then organizations who sincerely desire mission success must put as much effort in selecting managers and integrators as they do when designing the hardware, writing the software code and analyzing competitive proposals. This paper will discuss the necessary and

  2. Biological Sampling Variability Study

    SciTech Connect

    Amidan, Brett G.; Hutchison, Janine R.

    2016-11-08

    There are many sources of variability that exist in the sample collection and analysis process. This paper addresses many, but not all, sources of variability. The main focus of this paper was to better understand and estimate variability due to differences between samplers. Variability between days was also studied, as well as random variability within each sampler. Experiments were performed using multiple surface materials (ceramic and stainless steel), multiple contaminant concentrations (10 spores and 100 spores), and with and without the presence of interfering material. All testing was done with sponge sticks using 10-inch by 10-inch coupons. Bacillus atrophaeus was used as the BA surrogate. Spores were deposited using wet deposition. Grime was coated on the coupons which were planned to include the interfering material (Section 3.3). Samples were prepared and analyzed at PNNL using CDC protocol (Section 3.4) and then cultured and counted. Five samplers were trained so that samples were taken using the same protocol. Each sampler randomly sampled eight coupons each day, four coupons with 10 spores deposited and four coupons with 100 spores deposited. Each day consisted of one material being tested. The clean samples (no interfering materials) were run first, followed by the dirty samples (coated with interfering material). There was a significant difference in recovery efficiency between the coupons with 10 spores deposited (mean of 48.9%) and those with 100 spores deposited (mean of 59.8%). There was no general significant difference between the clean and dirty (containing interfering material) coupons or between the two surface materials; however, there was a significant interaction between concentration amount and presence of interfering material. The recovery efficiency was close to the same for coupons with 10 spores deposited, but for the coupons with 100 spores deposited, the recovery efficiency for the dirty samples was significantly larger (65

  3. Heart Rate Variability Analysis in General Medicine

    PubMed Central

    Gang, Yi; Malik, Marek

    2003-01-01

    Autonomic nervous system plays an integral role in homeostasis. Autonomic modulation can frequently be altered in patients with cardiac disorders as well as in patients with other critical illnesses or injuries. Assessment of heart rate variability is based on analysis of consecutive normal R-R intervals and may provide quantitative information on the modulation of cardiac vagal and sympathetic nerve input. The hypothesis that depressed heart rate variability may occur over a broad range of illness and injury, and may inversely correlated with disease severity and outcome has been tested in various clinical settings over the last decade. This article reviews recent literature concerning the potential clinical implications and limitations of heart rate variability assessment in general medicine. PMID:16943988

  4. Rating Variable Performance.

    ERIC Educational Resources Information Center

    Steiner, Dirk D.; Rain, Jeffrey S.

    Many empirical studies have examined factors that influence ratings of performance. This study examined the rating variable performance of a single individual. Serial position of a single poor or good performance in a series of otherwise good or poor performances was manipulated to examine its effects on both ratings and recommended actions toward…

  5. Variable gravity research facility

    NASA Technical Reports Server (NTRS)

    Allan, Sean; Ancheta, Stan; Beine, Donna; Cink, Brian; Eagon, Mark; Eckstein, Brett; Luhman, Dan; Mccowan, Daniel; Nations, James; Nordtvedt, Todd

    1988-01-01

    Spin and despin requirements; sequence of activities required to assemble the Variable Gravity Research Facility (VGRF); power systems technology; life support; thermal control systems; emergencies; communication systems; space station applications; experimental activities; computer modeling and simulation of tether vibration; cost analysis; configuration of the crew compartments; and tether lengths and rotation speeds are discussed.

  6. Variable Rate Irrigation

    USDA-ARS?s Scientific Manuscript database

    Systems are available to producers with the ability to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer a producer great cost savings; however, the full potential of these benefits and savings cannot...

  7. Variable rate irrigation

    USDA-ARS?s Scientific Manuscript database

    Systems are available to producers to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer cost savings to a producer; however, the full potential of the benefits and savings cannot be realized if water ...

  8. Lake Ontario: Nearshore Variability

    EPA Science Inventory

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  9. Continuously variable transmission

    SciTech Connect

    Itoh, H.; Okada, M.

    1986-11-25

    This patent describes a continuously variable transmission for transmitting a torque from an engine to a final reduction gear, comprising: an input shaft connected with the engine at one end thereof; a continuously variable transmission means having a driving pulley with a fixed member and a movable member, the movable member being actuated by an hydraulic cylinder to form a V-shaped opening between the fixed member and movable member, a driven pulley with another fixed member and another movable member. The other movable member is similarly actuated by another hydraulic cylinder to form another V-shaped opening between the other fixed member and the other movable member, and a belt member spanning the pulleys provides for a continuously variable transmission ratio; a planetary gear unit including a sun gear, a plurality of pinion gears which mesh with the sun gear and are connected with the driven pulley and a ring gear which meshes with the plurality of pinion gears; and a rotation transmitting means for transmitting rotation of the input shaft to the planetary gear unit. The rotation transmitting means is provided between the input shaft and the planetary gear unit and includes a shaft connected with the sun gear of the planetary gear unit and a first gear connected with the input shaft. The first gear is located between the engine and the continuously variable transmission means.

  10. Variable polarity arc welding

    NASA Technical Reports Server (NTRS)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  11. Variable camber rotor study

    NASA Technical Reports Server (NTRS)

    Dadone, L.; Cowan, J.; Mchugh, F. J.

    1982-01-01

    Deployment of variable camber concepts on helicopter rotors was analytically assessed. It was determined that variable camber extended the operating range of helicopters provided that the correct compromise can be obtained between performance/loads gains and mechanical complexity. A number of variable camber concepts were reviewed on a two dimensional basis to determine the usefulness of leading edge, trailing edge and overall camber variation schemes. The most powerful method to vary camber was through the trailing edge flaps undergoing relatively small motions (-5 deg to +15 deg). The aerodynamic characteristics of the NASA/Ames A-1 airfoil with 35% and 50% plain trailing edge flaps were determined by means of current subcritical and transonic airfoil design methods and used by rotor performance and loads analysis codes. The most promising variable camber schedule reviewed was a configuration with a 35% plain flap deployment in an on/off mode near the tip of a blade. Preliminary results show approximately 11% reduction in power is possible at 192 knots and a rotor thrust coefficient of 0.09. The potential demonstrated indicates a significant potential for expanding the operating envelope of the helicopter. Further investigation into improving the power saving and defining the improvement in the operational envelope of the helicopter is recommended.

  12. Variable Oakleaf Caterpillar

    Treesearch

    Louis F. Wilson; Gordon A. Surgeoner

    1979-01-01

    The variable oakleaf caterpillar (Heterocampa manteo (Dbldy.)) is a common insect in deciduous forests of Eastern North America. It has been recorded from most of the Eastern Canadian Provinces and most of the States in the East to North Dakota in the West and south to eastern Texas, Louisiana, and Mississippi. Heavy defoliations of hosts may occur anywhere within this...

  13. Species selection on variability.

    PubMed Central

    Lloyd, E A; Gould, S J

    1993-01-01

    Most analyses of species selection require emergent, as opposed to aggregate, characters at the species level. This "emergent character" approach tends to focus on the search for adaptations at the species level. Such an approach seems to banish the most potent evolutionary property of populations--variability itself--from arguments about species selection (for variation is an aggregate character). We wish, instead, to extend the legitimate domain of species selection to aggregate characters. This extension of selection theory to the species level will concentrate, instead, on the relation between fitness and the species character, whether aggregate or emergent. Examination of the role of genetic variability in the long-term evolution of clades illustrates the cogency of broadening the definition of species selection to include aggregate characters. We reinterpret, in this light, a classic case presented in support of species selection. As originally presented, the species selection explanation of volutid neogastropod evolution was vulnerable to a counterinterpretation at the organism level. Once this case is recast within a definition of species selection that reflects the essential structure and broad applicability of hierarchical selection models, the organism-level reinterpretation of variability loses its force. We conclude that species selection on variability is a major force of macroevolution. PMID:11607352

  14. Genetic variability in Macadamia

    USDA-ARS?s Scientific Manuscript database

    A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed usingeight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Md...

  15. Variable thrust cartridge

    DOEpatents

    Taleyarkhan, Rusi P.

    2000-11-07

    The present invention is a variable thrust cartridge comprising a water-molten aluminum reaction chamber from which a slug is propelled. The cartridge comprises a firing system that initiates a controlled explosion from the reaction chamber. The explosive force provides a thrust to a slug, preferably contained within the cartridge.

  16. White Noise Path Integrals in Stochastic Neurodynamics

    NASA Astrophysics Data System (ADS)

    Carpio-Bernido, M. Victoria; Bernido, Christopher C.

    2008-06-01

    The white noise path integral approach is used in stochastic modeling of neural activity, where the primary dynamical variables are the relative membrane potentials, while information on transmembrane ionic currents is contained in the drift coefficient. The white noise path integral allows a natural framework and can be evaluated explicitly to yield a closed form for the conditional probability density.

  17. The Development of Relational Integration during Childhood

    ERIC Educational Resources Information Center

    Dauvier, Bruno; Bailleux, Christine; Perret, Patrick

    2014-01-01

    Relational integration refers to the process whereby several variables are integrated within a single cognitive representation. In cognitive and developmental science, it is regarded as a central function of working memory that may contribute to the development of higher order processes, such as reasoning and fluid intelligence. In the present…

  18. The Development of Relational Integration during Childhood

    ERIC Educational Resources Information Center

    Dauvier, Bruno; Bailleux, Christine; Perret, Patrick

    2014-01-01

    Relational integration refers to the process whereby several variables are integrated within a single cognitive representation. In cognitive and developmental science, it is regarded as a central function of working memory that may contribute to the development of higher order processes, such as reasoning and fluid intelligence. In the present…

  19. Numerical Integration

    ERIC Educational Resources Information Center

    Sozio, Gerry

    2009-01-01

    Senior secondary students cover numerical integration techniques in their mathematics courses. In particular, students would be familiar with the "midpoint rule," the elementary "trapezoidal rule" and "Simpson's rule." This article derives these techniques by methods which secondary students may not be familiar with and an approach that…

  20. Information Integrity

    ERIC Educational Resources Information Center

    Graves, Eric

    2013-01-01

    This dissertation introduces the concept of Information Integrity, which is the detection and possible correction of information manipulation by any intermediary node in a communication system. As networks continue to grow in complexity, information theoretic security has failed to keep pace. As a result many parties whom want to communicate,…

  1. Information Integrity

    ERIC Educational Resources Information Center

    Graves, Eric

    2013-01-01

    This dissertation introduces the concept of Information Integrity, which is the detection and possible correction of information manipulation by any intermediary node in a communication system. As networks continue to grow in complexity, information theoretic security has failed to keep pace. As a result many parties whom want to communicate,…

  2. Tides and Decadal Variability

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    2003-01-01

    This paper reviews the mechanisms by which oceanic tides and decadal variability in the oceans are connected. We distinguish between variability caused by tides and variability observed in the tides themselves. Both effects have been detected at some level. The most obvious connection with decadal timescales is through the 18.6-year precession of the moon's orbit plane. This precession gives rise to a small tide of the same period and to 18.6-year modulations in the phase and amplitudes of short-period tides. The 18.6-year "node tide" is very small, no more than 2 cm anywhere, and in sea level data it is dominated by the ocean's natural Variability. Some authors have naively attributed climate variations with periods near 19 years directly to the node tide, but the amplitude of the tide is too small for this mechanism to be operative. The more likely explanation (Loder and Garrett, JGR, 83, 1967-70, 1978) is that the 18.6-y modulations in short-period tides, especially h e principal tide M2, cause variations in ocean mixing, which is then observed in temperature and other climatic indicators. Tidally forced variability has also been proposed by some authors, either in response to occasional (and highly predictable) tidal extremes or as a nonlinear low-frequency oscillation caused by interactions between short-period tides. The former mechanism can produce only short-duration events hardly more significant than normal tidal ranges, but the latter mechanism can in principle induce low-frequency oscillations. The most recent proposal of this type is by Keeling and Whorf, who highlight the 1800-year spectral peak discovered by Bond et al. (1997). But the proposal appears contrived and should be considered, in the words of Munk et al. (2002), "as the most likely among unlikely candidates."

  3. Tides and Decadal Variability

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    2003-01-01

    This paper reviews the mechanisms by which oceanic tides and decadal variability in the oceans are connected. We distinguish between variability caused by tides and variability observed in the tides themselves. Both effects have been detected at some level. The most obvious connection with decadal timescales is through the 18.6-year precession of the moon's orbit plane. This precession gives rise to a small tide of the same period and to 18.6-year modulations in the phase and amplitudes of short-period tides. The 18.6-year "node tide" is very small, no more than 2 cm anywhere, and in sea level data it is dominated by the ocean's natural Variability. Some authors have naively attributed climate variations with periods near 19 years directly to the node tide, but the amplitude of the tide is too small for this mechanism to be operative. The more likely explanation (Loder and Garrett, JGR, 83, 1967-70, 1978) is that the 18.6-y modulations in short-period tides, especially h e principal tide M2, cause variations in ocean mixing, which is then observed in temperature and other climatic indicators. Tidally forced variability has also been proposed by some authors, either in response to occasional (and highly predictable) tidal extremes or as a nonlinear low-frequency oscillation caused by interactions between short-period tides. The former mechanism can produce only short-duration events hardly more significant than normal tidal ranges, but the latter mechanism can in principle induce low-frequency oscillations. The most recent proposal of this type is by Keeling and Whorf, who highlight the 1800-year spectral peak discovered by Bond et al. (1997). But the proposal appears contrived and should be considered, in the words of Munk et al. (2002), "as the most likely among unlikely candidates."

  4. On the path integral of constrained systems

    SciTech Connect

    Muslih, Sami I.

    2004-10-04

    Constrained Hamiltonian systems are investigated by using Gueler's method. Integration of a set of equations of motion and the action function is discussed. It is shown that the canonical path integral quantization is obtained directly as an integration over the canonical phase-space coordinates without any need to enlarge the initial phase-space by introducing extra- unphysical variables as in the Batalin-Fradkin-Tyutin (BFT) method. The abelian Proca model is analyzed by the two methods.

  5. Variable White Dwarf Data Tables

    SciTech Connect

    Bradley, P. A.

    1997-12-31

    Below, I give a brief explanation of the information in these tables. In all cases, I list the WD {number_sign}, either from the catalog of McCook {ampersand} Sion (1987) or determined by me from the epoch 1950 coordinates. Next, I list the most commonly used name (or alias), then I list the variable star designation if it is available. If not, I list the constellation name and a V** or?? depending on what the last designated variable star for that constellation is. I present epoch 2000 coordinates for all of the stars, which I precessed from the 1950 ones in most cases. I do not include proper motion effects; this is negligible for all except the largest proper motion DAV stars, such as L 19-2, BPM 37093, B 808, and G 29-38. Even in these cases, the error is no more than 30` in declination and 2 s in right ascension. I culled effective temperatures from the latest work (listed under each table); they are now much more homogeneous than before. I pulled the magnitude estimates from the appropriate paper, and they are mean values integrated over several cycles. The amplitude given is for the height of a typical pulse in the light curve. The periods correspond the dominant ones found in the light curve. In some cases, there is a band of power in a given period range, or the light curve is very complex, and I indicate this in the table. In the references, I generally list the paper with the most comprehensive pulsation analysis for the star in question. In some cases, there is more than one good reference, and I list them as well.

  6. Integrated nanocatalysts.

    PubMed

    Zeng, Hua Chun

    2013-02-19

    Despite significant advancements in catalysis research, the prevailing catalyst technology remains largely an art rather than a science. Rapid development in the fields of nanotechnology and materials chemistry in the past few decades, however, provides us with a new capacity to re-examine existing catalyst design and processing methods. In recent years, "nanocatalysts" has become a term often used by the materials chemistry and catalysis community. It refers to heterogeneous catalysts at nanoscale dimensions. Similar to homogeneous catalysts, freestanding (unsupported) nanocatalysts are difficult to separate after use. Because of their small sizes, they are also likely to be cytotoxic and pose a threat to the environment and therefore may not be practical for industrial use. On the other hand, if they are supported on ordinary catalyst carriers, the nanocatalysts would then revert to act as conventional heterogeneous catalysts, since chemists have known active metal clusters or oxide particles in the nanoscale regime long before the nanotechnology era. To resolve this problem, we need new research directions and synthetic strategies. Important advancements in catalysis research now allow chemists to prepare catalytic materials with greater precision. By controlling particle composition, structure, shape, and dimension, researchers can move into the next phase of catalyst development if they can bridge these old and new technologies. In this regard, one way seems to be to integrate active nanostructured catalysts with boundary-defined catalyst supports that are "not-so-nano" in dimension. However, these supports still have available hierarchical pores and cavity spaces. In principle, these devices keep the essence of traditional "catalyst-plus-support" type systems. They also have the advantages of nanoscale engineering, which involves both high level design and integration processes in their fabrication. Besides this, the active components in these devices are

  7. Integrating maps requires integrated data

    SciTech Connect

    Weissenbach, J.; Bentolila, S.

    1996-06-01

    The molecular genetics movement has proceeded admirably thanks to new technologies such as polymerase chain reaction (PCR) sequencing. However, the integration of mapping data has not yet been achieved. This article discussing several problem areas and serves as a reminder of the urgency of such concerns.

  8. Continuously variable transmission

    SciTech Connect

    Tatara, Y.; Okawa, S.; Matsui, H.; Nakawaki, Y.

    1987-04-28

    A continuously variable transmission means is described for motor vehicles including a driving pulley with a fixed member and a movable member. The movable member is actuated by a hydraulic cylinder to form a V-shaped opening, a driven pulley with another fixed member and another movable member. Another movable member is actuated by another hydraulic cylinder to form another V-shaped opening, and a flexible endless member spans the driving and driven pulleys. The continuously variable transmission means comprises such items as: a first output shaft; a first gear; a second gear; a reverse gear; a second output shaft; a third gear; a jaw clutch mounted; a first one-way clutch; a fourth gear; a hydraulic clutch means; and a second one-way clutch.

  9. Medical examiner variability.

    PubMed

    Hinchcliffe, R

    1997-01-01

    There are undoubtedly many factors that contribute to inter-examiner variability relevant to the use of medical practitioners in justiciable matters. One source of variability with regard to claims relating to hearing disorders could well be the training and 'calibration' of medical examiners. A tentative analysis of the examination papers and of the declared roles of the specialties that provide these examiners lends support to such a thesis. One solution would be to train special specialists for medicolegal work, as envisaged by Boyarsky for forensic urology (Boyarsky, 1996). At the same time there is the need to change the role-perception of many examiners. There is also the need for medical examiners to express honest, unbiased opinions. There are also problems inherent in the litigation process which does not promote the interactive and adaptive processes between experts that characterise scientific discussions and enquiry.

  10. Gaia and variable stars

    NASA Astrophysics Data System (ADS)

    Eyer, Laurent; Holl, Berry; Mowlavi, Nami

    2014-01-01

    The study of variable phenomena (periodic, irregular or transient) provides a unique way to acquire knowledge about objects in our Universe. Currently, we are going through a rapid expansion of time-domain astrophysics. One reason for this expansion is the technological developments materialised in small to medium size observational projects such as HAT, OGLE, Catalina, PTF and upcoming very large projects such as Gaia or LSST. In this article, we are focusing on the ESA cornerstone mission Gaia. This spacecraft will provide astrometric, photometric and spectroscopic measurements for one billion stars. Among the existing and planned multi-epoch projects Gaia is unique because it will provide exquisite astrometric measurements for all objects it observes. We provide a brief overview of the literature concerning this mission and its expected contribution to variability studies.

  11. Intrinsically variable stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Querci, Monique

    1987-01-01

    The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

  12. [Socioeconomic variables and fertility].

    PubMed

    Arguello, O

    1980-08-01

    While making comparative analyses of data collected by the World Fertility Survey regarding Latin America, a group of investigators of CELADE (Centro Latinoamericano de Demografia) realized that the selection of economic variables for the study of fertility had serious limitations. Such limitations did not allow the elaboration of a theory which took into account the complicated process of fertility, in all its socioeconomic, cultural, and psychological manifestations. Thus, this paper intends to lay the theoretical basis for the selection of all relevant variables, distinguishing, for example, the average fertility of women according to area of residence, place of early socialization, migrant status, social status, occupation of husband, level of instruction, occupation, and all changes in occupational activities of women in fertile age.

  13. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1995-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  14. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1994-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  15. Intrinsically variable stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Querci, Monique

    1987-01-01

    The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

  16. RADIATION INTEGRATOR

    DOEpatents

    Glass, F.M.; Wilson, H.N.

    1959-02-17

    Radiation detecting and measuring systems, particularly a compact, integrating, background monitor, are discussed. One of the principal features of the system is the use of an electrometer tube where the input of the tube is directly connected to an electrode of the radiation detector and a capacitor is coupled to the tube input. When a predetermined quantity of radiation has been integrated, a trigger signal is fed to a recorder and a charge is delivered to the capacitor to render the tube inoperative. The capacitor is then recharged for the next period of operation. With this arrangement there is a substantial reduction in lead lengths and the principal components may be enclosed and hermetically sealed to insure low leakage.

  17. Variable percentage sampler

    DOEpatents

    Miller, Jr., William H.

    1976-01-01

    A remotely operable sampler is provided for obtaining variable percentage samples of nuclear fuel particles and the like for analyses. The sampler has a rotating cup for a sample collection chamber designed so that the effective size of the sample inlet opening to the cup varies with rotational speed. Samples of a desired size are withdrawn from a flowing stream of particles without a deterrent to the flow of remaining particles.

  18. Climate Variability Program

    NASA Technical Reports Server (NTRS)

    Halpern, David (Editor)

    2002-01-01

    The Annual Report of the Climate Variability Program briefly describes research activities of Principal Investigators who are funded by NASA's Earth Science Enterprise Research Division. The report is focused on the year 2001. Utilization of satellite observations is a singularity of research on climate science and technology at JPL (Jet Propulsion Laboratory). Research at JPL has two foci: generate new knowledge and develop new technology.

  19. Variable laser attenuator

    DOEpatents

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  20. Variable laser attenuator

    DOEpatents

    Foltyn, S.R.

    1987-05-29

    The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

  1. Variable depth core sampler

    DOEpatents

    Bourgeois, Peter M.; Reger, Robert J.

    1996-01-01

    A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

  2. Variable reluctance drive system

    SciTech Connect

    Lipo, T.A.; Liang, F.

    1995-10-17

    A variable reluctance drive system including a motor and corresponding converter for improved current commutation is described. The motor incorporates a salient pole rotor and a salient pole stator having one or more full pitch windings which operate by mutual inductance to transfer the current from the active short pitch winding following phase alignment. This increases output torque and/or speed and permits a number of simple and economical converter circuits. 17 figs.

  3. Variable depth core sampler

    DOEpatents

    Bourgeois, P.M.; Reger, R.J.

    1996-02-20

    A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

  4. Atmospheric Infrared Radiance Variability.

    DTIC Science & Technology

    1981-05-27

    RADIANCE MODEL - T. C. Degges 9 3. MODELS OF THE VARIABILITY OF ATMOSPHERIC PROPERTIES - C. H. Humphrey and C. R. Philbrick 25 4. EFFECTS OF...variations of the infrared emissions with geophysical parameters, such as latitude or magnetic activity, or with localized dynamic effects . Thus, to obtain...aurora. However, the largest heat- ing effects result from plasma interactions with the neutral atmosphere when electric and magnetic fields accelerate

  5. Integrated Optics.

    DTIC Science & Technology

    1974-10-01

    the attractive option of varying the bandgap F.S well as the refractive index. The crystal growth equipment was modified to grow epitaxial layers...loss .or1 us6 in optical integrated circuits. The limited melt slidebar method is most useful for growing double layers of Gan xiAlyAs...limited melt graphite slide bar, and infinite melt. We were able to grow GaAs layers on (GaADAs substrates using the vapor growth method and

  6. Integrated Fluorescence

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret (Inventor); Gruhlke, Russell W. (Inventor)

    1998-01-01

    A detection method is integrated with a filtering method and an enhancement method to create a fluorescence sensor that can be miniaturized. The fluorescence sensor comprises a thin film geometry including a waveguide layer, a metal film layer and sensor layer. The thin film geometry of the fluorescence sensor allows the detection of fluorescent radiation over a narrow wavelength interval. This enables wavelength discrimination and eliminates the detection of unwanted light from unknown or spurious sources.

  7. Evoked Potential Variability

    PubMed Central

    Hu, Lingli; Boutros, Nash N.; Jansen, Ben H.

    2008-01-01

    An unsupervised correlation-based clustering method was developed to assess the trial-to-trial variability of auditory evoked potentials (AEPs). The method first decomposes single trials into three frequency bands, each containing activity primarily associated with one of the three major AEP components, i.e., P50, N100 and P200. Next, single-trial evoked potentials with similar post-stimulus characteristics are clustered and selectively averaged to determine the presence or absence of an AEP component. The method was evaluated on actual AEP and spontaneous EEG data collected from 25 healthy participants using a paradigm in which pairs of identical tones were presented, with the first stimulus (S1) presented 0.5 s before the second stimulus (S2). Homogeneous, well-separated clusters were obtained and substantial AEP variability was found. Also, there was a trend for S2 to produce fewer ‘complete’ (and significantly smaller) responses than S1. Tests conducted on spontaneous EEG produced similar clusters as obtained from EP data, but significantly fewer stimuli produced responses containing all three EP components than seen in AEP data. These findings suggest that the clustering method presented here performs adequately to assess trial-to-trial EP variability. Also, the results suggest that the sensory gating observed in normal controls may be caused by the fact that the second stimulus generates fewer ‘responsive’ trials than the first stimulus, thus resulting in smaller ensemble averages. PMID:19103222

  8. Variable displacement vane pump

    SciTech Connect

    Tschantz, J.S.; Bisson, B.J.

    1997-12-31

    What has been developed under this program is a pumping system which can vary the amount of fuel delivered according to engine needs, thereby reducing the temperature rise of the fuel to very low levels. This permits the elimination of the air/oil coolers and conserves the vital airflow through the fan. The variable displacement vane pump (VDVP) also permits a substantial simplification of the control system with the elimination of complex metering valves, offering a significant reduction in fuel system cost. This program was initiated to develop a technology that embodied the ruggedness of the gear pump with the efficiency and metering versatility of the variable displacement vane pump. Thick metal vanes emulate the teeth on pumping gears while the simple, elegant swing cam feature provides the variable displacement capability without the unwieldy multiple cam segments found in other concepts. The result is a pumping architecture which is rugged, light in weight and extremely versatile, having demonstrated superb heat management and controllability in extensive bench and engine testing. This paper will report the results that the pumps have achieved to date both in terms of durability and efficiency.

  9. [Population variables as fundamental in development planning].

    PubMed

    Diongue, A; Sow, E B

    1990-03-01

    This article summarizes the major points extracted from an interview with the Head of the Population Division at the Economic Commission for Africa (ECA) regarding the problems of integrating population variables with the socioeconomic development of developing countries. 1) The Kilimanjaro Program of Action remains the basic framework that ECA uses as a reference point in matters pertaining to population; 2) Regarding the World Bank and the International Monetary Fund's structural adjustment policies (SAP's), ECA's position is one which stresses the need to ensure that the social aspects of SAP's are met in the short term such as the needs of the aged, women and children; however, population problems are long-term and require long-term solutions; 3) During the past 15-20 years population issues have not been properly integrated in the short-term solutions to development problems; ECA encourages governments to integrate demographic variables and population issues in their development plans to achieve long-term solutions; however, the short-term obstacles include infant mortality, infectious diseases and the debt crisis; 4) ECA has proposed an African Alternative SAP (AASAP) to highlight the existence of social problems and the multiple variables affecting the African countries; the AASAP also encourages regional cooperation to strengthen the negotiating position to obtain more resources that with effective management systems can improve the conditions of individual countries; 5) family planning and contraception remain integral components of a population policy and it is important that governments recognize the need to fight against infant and maternal mortality. Family planning encompasses much more than contraception.

  10. Indonesian Throughflow variability in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Santoso, Agus; England, Matthew; Kajtar, Jules; Cai, Wenju

    2015-04-01

    The Indonesian Throughflow (ITF) is an integral component of the Earth's climate. The state of ocean and atmospheric circulations, and thus climate variability, is dependent upon changes in the ITF which impact on heat and salt balance across the Indo-Pacific oceans. Understanding its variability and link with major drivers of Indo-Pacific climate variability however remains elusive due to limited direct observational data. A multi-model ensemble approach is needed to help bridge this gap. Using 20 models that participated in the Coupled Model Intercomparison Project fifth instalment (CMIP5), and an ocean reanalysis as a reference, we find that local processes in the Indian Ocean side play a more dominant role on ITF variability than the El Nino Southern Oscillation (ENSO). This is corroborated by the high inter-model correlation between the variability amplitude of the ITF and that of the zonal winds south of the Maritime Continent, but not with ENSO amplitude. The Indian Ocean forcing is associated with surface-intensified transport anomaly, while the ENSO forcing primarily with anomalous subsurface transport. These links are substantiated by the mean state change under greenhouse warming in that the projected weakening of the ITF is found robust only at subsurface, consistent with the lack of inter-model consensus in the change of the Indian Ocean local wind forcing.

  11. High-energy sources before INTEGRAL. INTEGRAL reference catalog

    NASA Astrophysics Data System (ADS)

    Ebisawa, K.; Bourban, G.; Bodaghee, A.; Mowlavi, N.; Courvoisier, T. J.-L.

    2003-11-01

    We describe the INTEGRAL reference catalog which classifies previously known bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources are, or have been at least once, brighter than ~ 1 mCrab above 3 keV, and are expected to be detected by INTEGRAL. This catalog is being used in the INTEGRAL Quick Look Analysis to discover new sources or significantly variable sources. We compiled several published X-ray and gamma-ray catalogs, and surveyed recent publications for new sources. Consequently, there are 1122 sources in our INTEGRAL reference catalog. In addition to the source positions, we show an approximate spectral model and expected flux for each source, based on which we derive expected INTEGRAL counting rates. Assuming the default instrument performances and at least ~ 105 s exposure time for any part of the sky, we expect that INTEGRAL will detect at least ~ 700 sources below 10 keV and ~ 400 sources above 20 keV over the mission life. The Catalog is available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?/A+A/411/L59

  12. Individual Movement Variability Magnitudes Are Explained by Cortical Neural Variability.

    PubMed

    Haar, Shlomi; Donchin, Opher; Dinstein, Ilan

    2017-09-13

    Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior-parietal cortex of individual subjects explained their movement-extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities.SIGNIFICANCE STATEMENT Neural activity and movement kinematics are remarkably variable. Although intertrial variability is rarely studied, here, we demonstrate that individual human subjects exhibit distinct magnitudes of neural and kinematic variability that are reproducible across movements to different targets and when performing these movements with either arm. Furthermore, when examining the relationship between cortical variability and movement variability, we find that cortical fMRI variability in parietal cortex of individual subjects explained their movement extent variability. This enabled us to explain why some subjects

  13. Gravity dependence of subjective visual vertical variability.

    PubMed

    Tarnutzer, A A; Bockisch, C; Straumann, D; Olasagasti, I

    2009-09-01

    The brain integrates sensory input from the otolith organs, the semicircular canals, and the somatosensory and visual systems to determine self-orientation relative to gravity. Only the otoliths directly sense the gravito-inertial force vector and therefore provide the major input for perceiving static head-roll relative to gravity, as measured by the subjective visual vertical (SVV). Intraindividual SVV variability increases with head roll, which suggests that the effectiveness of the otolith signal is roll-angle dependent. We asked whether SVV variability reflects the spatial distribution of the otolithic sensors and the otolith-derived acceleration estimate. Subjects were placed in different roll orientations (0-360 degrees, 15 degrees steps) and asked to align an arrow with perceived vertical. Variability was minimal in upright, increased with head-roll peaking around 120-135 degrees, and decreased to intermediate values at 180 degrees. Otolith-dependent variability was modeled by taking into consideration the nonuniform distribution of the otolith afferents and their nonlinear firing rate. The otolith-derived estimate was combined with an internal bias shifting the estimated gravity-vector toward the body-longitudinal. Assuming an efficient otolith estimator at all roll angles, peak variability of the model matched our data; however, modeled variability in upside-down and upright positions was very similar, which is at odds with our findings. By decreasing the effectiveness of the otolith estimator with increasing roll, simulated variability matched our experimental findings better. We suggest that modulations of SVV precision in the roll plane are related to the properties of the otolith sensors and to central computational mechanisms that are not optimally tuned for roll-angles distant from upright.

  14. Integrative Bioengineering Institute

    SciTech Connect

    Eddington, David; Magin,L,Richard; Hetling, John; Cho, Michael

    2009-01-09

    Microfabrication enables many exciting experimental possibilities for medicine and biology that are not attainable through traditional methods. However, in order for microfabricated devices to have an impact they must not only provide a robust solution to a current unmet need, but also be simple enough to seamlessly integrate into standard protocols. Broad dissemination of bioMEMS has been stymied by the common aim of replacing established and well accepted protocols with equally or more complex devices, methods, or materials. The marriage of a complex, difficult to fabricate bioMEMS device with a highly variable biological system is rarely successful. Instead, the design philosophy of my lab aims to leverage a beneficial microscale phenomena (e.g. fast diffusion at the microscale) within a bioMEMS device and adapt to established methods (e.g. multiwell plate cell culture) and demonstrate a new paradigm for the field (adapt instead of replace). In order for the field of bioMEMS to mature beyond novel proof-of-concept demonstrations, researchers must focus on developing systems leveraging these phenomena and integrating into standard labs, which have largely been ignored. Towards this aim, the Integrative Bioengineering Institute has been established.

  15. Modeling the variability of firing rate of retinal ganglion cells.

    PubMed

    Levine, M W

    1992-12-01

    Impulse trains simulating the maintained discharges of retinal ganglion cells were generated by digital realizations of the integrate-and-fire model. If the mean rate were set by a "bias" level added to "noise," the variability of firing would be related to the mean firing rate as an inverse square root law; the maintained discharges of retinal ganglion cells deviate systematically from such a relationship. A more realistic relationship can be obtained if the integrate-and-fire mechanism is "leaky"; with this refinement, the integrate-and-fire model captures the essential features of the data. However, the model shows that the distribution of intervals is insensitive to that of the underlying variability. The leakage time constant, threshold, and distribution of the noise are confounded, rendering the model unspecifiable. Another aspect of variability is presented by the variance of responses to repeated discrete stimuli. The variance of response rate increases with the mean response amplitude; the nature of that relationship depends on the duration of the periods in which the response is sampled. These results have defied explanation. But if it is assumed that variability depends on mean rate in the way observed for maintained discharges, the variability of responses to abrupt changes in lighting can be predicted from the observed mean responses. The parameters that provide the best fits for the variability of responses also provide a reasonable fit to the variability of maintained discharges.

  16. Neural mechanisms for evaluating environmental variability in Caenorhabditis elegans

    PubMed Central

    Calhoun, Adam J.; Tong, Ada; Pokala, Navin; Fitzpatrick, James A. J.; Sharpee, Tatyana O.; Chalasani, Sreekanth H.

    2015-01-01

    Summary The ability to evaluate variability in the environment is vital for making optimal behavioral decisions. Here we show that Caenorhabditis elegans evaluates variability in its food environment and then modifies its future behavior accordingly. We derived a behavioral model that reveals a critical period over which information about the food environment is acquired and predicts future search behavior. We identified a pair of high-threshold sensory neurons that encode variability in food concentration and downstream dopamine-dependent circuitry that generates appropriate search behavior upon removal from food. Further, we show that CREB is required in a subset of interneurons and determines the timescale over which the variability is integrated. Interestingly, the variability circuit is a subset of a larger circuit driving search behavior, showing that learning directly modifies the very same neurons driving behavior. Our study reveals how a neural circuit decodes environmental variability to generate contextually appropriate decisions. PMID:25864633

  17. Neural Mechanisms for Evaluating Environmental Variability in Caenorhabditis elegans.

    PubMed

    Calhoun, Adam J; Tong, Ada; Pokala, Navin; Fitzpatrick, James A J; Sharpee, Tatyana O; Chalasani, Sreekanth H

    2015-04-22

    The ability to evaluate variability in the environment is vital for making optimal behavioral decisions. Here we show that Caenorhabditis elegans evaluates variability in its food environment and modifies its future behavior accordingly. We derive a behavioral model that reveals a critical period over which information about the food environment is acquired and predicts future search behavior. We also identify a pair of high-threshold sensory neurons that encode variability in food concentration and the downstream dopamine-dependent circuit that generates appropriate search behavior upon removal from food. Further, we show that CREB is required in a subset of interneurons and determines the timescale over which the variability is integrated. Interestingly, the variability circuit is a subset of a larger circuit driving search behavior, showing that learning directly modifies the very same neurons driving behavior. Our study reveals how a neural circuit decodes environmental variability to generate contextually appropriate decisions. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Variable sensitivity moire interferometry

    NASA Technical Reports Server (NTRS)

    Johnson-Cole, Helen; Bennewitz, James H.; Gilbert, John A.

    1991-01-01

    This paper demonstrates that optical microlithography can be used to produce a crossed grating which diffracts light into multiple orders sufficient to record moire interferograms with sensitivities ranging from 2.0 to 0.285 micron/fringe. The grating profile produced by the method is analyzed to establish the diffraction efficiency in each diffraction order, and generalized expressions are given for variable sensitivity moire interferometry. Experimental tests are conducted to verify analytical arguments. In one of these tests, two different diffraction order pairs are used simultaneously to verify that surface displacement can be measured at different sensitivities.

  19. Variable camshaft timing system

    SciTech Connect

    Butterfield, R.P.; Smith, F.R.

    1989-09-05

    This patent describes an improvement in a variable camshaft timing system for an internal combustion engine having intake and exhaust valves and a camshaft for each of the intake and exhaust valves, an intake sprocket and an exhaust sprocket keyed to their respective camshaft, only one of the camshafts being directly driven by an engine crankshaft, and a timing chain engaging both sprockets. The improvement comprising a single bracket carrying at least one idler sprocket engaging the timing chain, the bracket being mounted for movement to alter the timing relationship between the intake and exhaust sprockets.

  20. Frictionless continuously variable transmission

    SciTech Connect

    Korban, J.F.; Korban, N.F.

    1989-07-25

    This patent describes an infinitely variable speed transmission. It comprises: an input shaft; a drive plate having a plurality of radial slots therein, the drive plate fixed to the input shaft; an output shaft parallel to the input shaft; a bevel gear fixed to the output shaft; a plurality if independently rotatable sprocketed pinions freely rotatable about and meshing with the bevel gear. The pinions also engaging the drive plate by projections from the pinions slidably mounted in the radial slots in the drive plate; and clutching means for selectively locking and unlocking the pinions in sequence to effect driving of the bevel gear.

  1. Variable pressure washer

    NASA Technical Reports Server (NTRS)

    Smeltzer, III, Stanley S. (Inventor); Estrada, Hector (Inventor)

    2004-01-01

    A variable pressure washer has two interlocking channel rings separated by a channel and retained by a captive set of fasteners. Within the channel between the rings are multiple rows of springs having at least two different spring moduli. The washer is particularly suited for use with a polar boss assembly secured to a bulkhead of a pressure vessel such as of propellent tank dome structure where the washer allows for the substantially uniform deflection of multiple O-rings as affected by the curved structure.

  2. Variable focal length microlenses

    NASA Astrophysics Data System (ADS)

    L. G., Commander; Day, S. E.; Selviah, D. R.

    2000-04-01

    Refractive surface relief microlenses (150 μm diameter) are immersed in nematic liquid crystal in a cell. Application of a variable voltage across the cell effectively varies the refractive index of the liquid crystal and results in a change of the focal length by the lensmakers formula (E. Hecht, Optics, 2nd edn., Addison-Wesley, Reading, Massachusetts, 1987, p. 138). We describe the cell design and construction and demonstrate a range of focal lengths from +490 to +1000 μm for 2 to 12 V applied. A diverging lens results when the voltage is lower. Theoretical models are developed to account for some of the observed aberrations.

  3. Variable capacity flywheel

    SciTech Connect

    Ban, M.

    1985-06-04

    A variable capacity flywheel comprises a main flywheel coupled with the rotating shaft of an engine and at least one rotatable auxiliary flywheel. Both are selectively engaged and disengaged with one another by means of an electromagnetic clutch. Both flywheels are engaged with one another by an energizing member in the low speed range of said engine. Both are disengaged from one another by means of excitation control of the electromagnetic clutch in the high speed range of the engine. A generator driven by the engine rotating shaft is connected in series with the electromagnetic clutch and a battery.

  4. Variable leak gas source

    DOEpatents

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A variable leak gas source and a method for obtaining the same which includes filling a quantity of hollow glass micro-spheres with a gas, storing said quantity in a confined chamber having a controllable outlet, heating said chamber above room temperature, and controlling the temperature of said chamber to control the quantity of gas passing out of said controllable outlet. Individual gas filled spheres may be utilized for calibration purposes by breaking a sphere having a known quantity of a known gas to calibrate a gas detection apparatus.

  5. Symbolic dynamics marker of heart rate variability combined with clinical variables enhance obstructive sleep apnea screening

    NASA Astrophysics Data System (ADS)

    Ravelo-García, A. G.; Saavedra-Santana, P.; Juliá-Serdá, G.; Navarro-Mesa, J. L.; Navarro-Esteva, J.; Álvarez-López, X.; Gapelyuk, A.; Penzel, T.; Wessel, N.

    2014-06-01

    Many sleep centres try to perform a reduced portable test in order to decrease the number of overnight polysomnographies that are expensive, time-consuming, and disturbing. With some limitations, heart rate variability (HRV) has been useful in this task. The aim of this investigation was to evaluate if inclusion of symbolic dynamics variables to a logistic regression model integrating clinical and physical variables, can improve the detection of subjects for further polysomnographies. To our knowledge, this is the first contribution that innovates in that strategy. A group of 133 patients has been referred to the sleep center for suspected sleep apnea. Clinical assessment of the patients consisted of a sleep related questionnaire and a physical examination. The clinical variables related to apnea and selected in the statistical model were age (p < 10-3), neck circumference (p < 10-3), score on a questionnaire scale intended to quantify daytime sleepiness (p < 10-3), and intensity of snoring (p < 10-3). The validation of this model demonstrated an increase in classification performance when a variable based on non-linear dynamics of HRV (p < 0.01) was used additionally to the other variables. For diagnostic rule based only on clinical and physical variables, the corresponding area under the receiver operating characteristic (ROC) curve was 0.907 (95% confidence interval (CI) = 0.848, 0.967), (sensitivity 87.10% and specificity 80%). For the model including the average of a symbolic dynamic variable, the area under the ROC curve was increased to 0.941 (95% = 0.897, 0.985), (sensitivity 88.71% and specificity 82.86%). In conclusion, symbolic dynamics, coupled with significant clinical and physical variables can help to prioritize polysomnographies in patients with a high probability of apnea. In addition, the processing of the HRV is a well established low cost and robust technique.

  6. Integration, Continuity and a Connection with Probability Density Functions

    ERIC Educational Resources Information Center

    Samuels, M.

    2006-01-01

    This note considers functions of two variables which are continuous on a possibly unbounded closed region in [vertical bar]R[squared], and the functions of one variable obtained by integrating out the other variable over this region. The question of continuity of these functions is investigated, as are connections with joint density and marginal…

  7. Superhumps in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Patterson, J.

    2006-05-01

    The individual telescopes of the CBA produce fast (<1 min) photometry of variable stars. With runs of >5 hours and spliced data from many longitudes, we aim to assemble long light curves with nearly continuous coverage. This is an ideal data base for period and other timing studies. I have found it to be many times more effective than one large telescope proudly performing its hijinks on one mountaintop. I'll give a brief account of how this enterprise has evolved from one CCD in a tuna fish can to the world's leading supplier of periodic signals in cataclysmic variables. The most interesting and productive research program has been the discovery and study of "superhumps", mysterious large-amplitude waves at a period slightly offset from the true orbital period of the binary. These result from the "precession" of the accretion disk. The disks appear to wobble and precess in a manner similar to the Moon's orbit, and we can use this as a tool for weighing the unseen secondary stars. I'll describe the superhumps, and their fascinating astrophysical uses.

  8. Suspended graphene variable capacitor

    NASA Astrophysics Data System (ADS)

    AbdelGhany, M.; Mahvash, F.; Mukhopadhyay, M.; Favron, A.; Martel, R.; Siaj, M.; Szkopek, T.

    2016-12-01

    Electromechanical variable capacitors, or varactors, find a wide range of applications including sensing applications and the tuning of electrical circuit resonance. We demonstrate a nano-electromechanical graphene varactor, a variable capacitor wherein the capacitance is tuned by voltage controlled deflection of a dense array of suspended graphene membranes. The low flexural rigidity of graphene monolayers is exploited to achieve low actuation voltage and high tunable capacitance density in an ultra-thin structure. Large arrays comprising thousands of suspensions were fabricated to give a tunable capacitance of over 10 pF mm-2. This capacitance density suggests that graphene offers a potential solution to the challenge of reducing the size of micro-electromechanical systems (MEMS). A capacitance tuning of 55% was achieved with a 10 V actuating voltage, exceeding the 50% tuning limit of Hookean parallel plate pull-in without the use of complex mechanical schemes that occupy substrate area. Capacitor behavior was investigated experimentally, and described by a simple theoretical model. Mechanical properties of the graphene membranes were measured independently using atomic force microscopy. We present a comparison of state-of-the-art MEMS and graphene varactors. The quality factor of graphene varactors is limited by graphene sheet resistance, pull-in voltage can be improved with more aggressive scaling, while the power handling and cycling stability of graphene varactors remains unknown.

  9. Glycemic variability: Clinical implications.

    PubMed

    Satya Krishna, Surabhi Venkata; Kota, Sunil K; Modi, Kirtikumar D

    2013-07-01

    Glycemic control and its benefits in preventing microvascular diabetic complications are convincingly proved by various prospective trials. Diabetes control and complications trial (DCCT) had reported variable glycated hemoglobin (HbA1C) as a cause of increased microvascular complications in conventional glycemic control group versus intensive one. However, in spite of several indirect evidences, its link with cardiovascular events or macrovascular complications is still not proved. Glycemic variability (GV) is one more tool to explain relation between hyperglycemia and increased cardiovascular risk in diabetic patients. In fact GV along with fasting blood sugar, postprandial blood sugar, HbA1C, and quality of life has been proposed to form glycemic pentad, which needs to be considered in diabetes management. Postprandial spikes in blood glucose as well as hypoglycemic events, both are blamed for increased cardiovascular events in Type 2 diabetics. GV includes both these events and hence minimizing GV can prevent future cardiovascular events. Modern diabetes management modalities including improved sulfonylureas, glucagon like peptide-1 (GLP-1)-based therapy, newer basal insulins, and modern insulin pumps address the issue of GV effectively. This article highlights mechanism, clinical implications, and measures to control GV in clinical practice.

  10. Variable gravity research facility

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Eight fourth-year engineering design students formed two teams to study methods of varying the perceived gravity level in a variable gravity research facility. A tether system and an arm system were the chosen topics. Both teams have produced and built scale models of their design. In addition, a three-credit Special Topics Course (Aviation 370) was formed, as the project offers an excellent opportunity to build a multi-disciplinary program around the initial conceptualization process. Fifty students were registered in the Special Topics course. Each week during a three hour class, a guest lecturer covered one or more of the many areas associated with the concept of a variable-gravity facility. The students formed small groups organized on a multi-disciplinary basis (there were twelve separate disciplines represented by one or more students) where they discussed among themselves the various issues involved. These groups also met outside class for three or more hours each week. During class each group presented oral reports on their findings during a one-hour general question and answer period.

  11. Glycemic variability: Clinical implications

    PubMed Central

    Satya Krishna, Surabhi Venkata; Kota, Sunil K.; Modi, Kirtikumar D.

    2013-01-01

    Glycemic control and its benefits in preventing microvascular diabetic complications are convincingly proved by various prospective trials. Diabetes control and complications trial (DCCT) had reported variable glycated hemoglobin (HbA1C) as a cause of increased microvascular complications in conventional glycemic control group versus intensive one. However, in spite of several indirect evidences, its link with cardiovascular events or macrovascular complications is still not proved. Glycemic variability (GV) is one more tool to explain relation between hyperglycemia and increased cardiovascular risk in diabetic patients. In fact GV along with fasting blood sugar, postprandial blood sugar, HbA1C, and quality of life has been proposed to form glycemic pentad, which needs to be considered in diabetes management. Postprandial spikes in blood glucose as well as hypoglycemic events, both are blamed for increased cardiovascular events in Type 2 diabetics. GV includes both these events and hence minimizing GV can prevent future cardiovascular events. Modern diabetes management modalities including improved sulfonylureas, glucagon like peptide-1 (GLP-1)-based therapy, newer basal insulins, and modern insulin pumps address the issue of GV effectively. This article highlights mechanism, clinical implications, and measures to control GV in clinical practice. PMID:23961476

  12. Understanding Solar Cycle Variability

    NASA Astrophysics Data System (ADS)

    Cameron, R. H.; Schüssler, M.

    2017-07-01

    The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock-Leighton-type dynamo model confirm the validity of the normal-mode approach.

  13. Variable venturi type carburetor

    SciTech Connect

    Tahata, M.

    1986-09-02

    A variable venturi type carburetor is described comprising a carburetor body provided with a suction passage therein for flow of air through the passage, a slide valve supported by the body for slidable movement across the suction passage to serve as a variable venturi, a butterfly throttle valve pivotably supported by the carburetor body downstream of the slide valve, interlocking means connecting the slide valve and the butterfly throttle valve together for operating in correspondence with one another, operating means connected to one of the valves for operating the same by application of an external force thereto. A low-speed fuel nozzle opens into the suction passage in the vicinity of the butterfly throttle valve, an intermediate and a high speed main fuel nozzle opens into the suction passage opposite the slide valve, and a low and intermediate-speed primary fuel nozzle opens into the suction passage between the slide valve and the butterfly throttle valve. The slide valve includes a bottom portion having a front side surface facing upstream in the suction passage and a rear side surface facing downstream in the suction passage, the front and rear side surfaces having lower edges which are located in the same horizontal plane, the rear side surface being provided with an inverted cutaway.

  14. Aflatoxin variability in pistachios.

    PubMed Central

    Mahoney, N E; Rodriguez, S B

    1996-01-01

    Pistachio fruit components, including hulls (mesocarps and epicarps), seed coats (testas), and kernels (seeds), all contribute to variable aflatoxin content in pistachios. Fresh pistachio kernels were individually inoculated with Aspergillus flavus and incubated 7 or 10 days. Hulled, shelled kernels were either left intact or wounded prior to inoculation. Wounded kernels, with or without the seed coat, were readily colonized by A. flavus and after 10 days of incubation contained 37 times more aflatoxin than similarly treated unwounded kernels. The aflatoxin levels in the individual wounded pistachios were highly variable. Neither fungal colonization nor aflatoxin was detected in intact kernels without seed coats. Intact kernels with seed coats had limited fungal colonization and low aflatoxin concentrations compared with their wounded counterparts. Despite substantial fungal colonization of wounded hulls, aflatoxin was not detected in hulls. Aflatoxin levels were significantly lower in wounded kernels with hulls than in kernels of hulled pistachios. Both the seed coat and a water-soluble extract of hulls suppressed aflatoxin production by A. flavus. PMID:8919781

  15. Score test variable screening

    PubMed Central

    Zhao, Sihai Dave; Li, Yi

    2015-01-01

    Variable screening has emerged as a crucial first step in the analysis of high-throughput data, but existing procedures can be computationally cumbersome, difficult to justify theoretically, or inapplicable to certain types of analyses. Motivated by a high-dimensional censored quantile regression problem in multiple myeloma genomics, this paper makes three contributions. First, we establish a score test-based screening framework, which is widely applicable, extremely computationally efficient, and relatively simple to justify. Secondly, we propose a resampling-based procedure for selecting the number of variables to retain after screening according to the principle of reproducibility. Finally, we propose a new iterative score test screening method which is closely related to sparse regression. In simulations we apply our methods to four different regression models and show that they can outperform existing procedures. We also apply score test screening to an analysis of gene expression data from multiple myeloma patients using a censored quantile regression model to identify high-risk genes. PMID:25124197

  16. Interoperator variability during polishing.

    PubMed

    Jones, Colin S; Billington, Richard W; Pearson, Gavin J

    2006-03-01

    The object of this study was to establish the 3 variables used in polishing by measuring the range of loads, speeds, and times used by practitioners when finishing and polishing samples of amalgam, resin composite, and glass-ionomer cement. These parameters could then be used to establish clinically relevant values that might optimize clinical finishing techniques. Samples of the 3 materials were attached to the load cell of a universal testing machine that was attached to an X-Y plotter. Practitioners were asked to finish the samples using 4 grades of a polishing disk system. Prior to using each grade of disk, the practitioner selected a speed. The sample was finished using one grade of disk until the practitioner was satisfied with the finish achieved. The process was then repeated with the next grade of disk. From the tracings for each disk the load and time were calculated. There was a wide variation in the loads, speeds, and times used by the practitioners to finish the 3 materials, and it was not possible to find any relationship among the 3 variables. It appeared that practitioners finished the materials in an arbitrary manner. No clear evidence was obtained to determine optimal combinations of load, speed, and time for finishing of amalgam, resin composite, or glass-ionomer cement. However, the results of this study indicate a range of values commonly used for each parameter in clinical practice, which could be useful for manufacturers in providing finishing instructions for their products.

  17. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  18. Current Climate Variability & Change

    NASA Astrophysics Data System (ADS)

    Diem, J.; Criswell, B.; Elliott, W. C.

    2013-12-01

    Current Climate Variability & Change is the ninth among a suite of ten interconnected, sequential labs that address all 39 climate-literacy concepts in the U.S. Global Change Research Program's Climate Literacy: The Essential Principles of Climate Sciences. The labs are as follows: Solar Radiation & Seasons, Stratospheric Ozone, The Troposphere, The Carbon Cycle, Global Surface Temperature, Glacial-Interglacial Cycles, Temperature Changes over the Past Millennium, Climates & Ecosystems, Current Climate Variability & Change, and Future Climate Change. All are inquiry-based, on-line products designed in a way that enables students to construct their own knowledge of a topic. Questions representative of various levels of Webb's depth of knowledge are embedded in each lab. In addition to the embedded questions, each lab has three or four essential questions related to the driving questions for the lab suite. These essential questions are presented as statements at the beginning of the material to represent the lab objectives, and then are asked at the end as questions to function as a summative assessment. For example, the Current Climate Variability & Change is built around these essential questions: (1) What has happened to the global temperature at the Earth's surface, in the middle troposphere, and in the lower stratosphere over the past several decades?; (2) What is the most likely cause of the changes in global temperature over the past several decades and what evidence is there that this is the cause?; and (3) What have been some of the clearly defined effects of the change in global temperature on the atmosphere and other spheres of the Earth system? An introductory Prezi allows the instructor to assess students' prior knowledge in relation to these questions, while also providing 'hooks' to pique their interest related to the topic. The lab begins by presenting examples of and key differences between climate variability (e.g., Mt. Pinatubo eruption) and

  19. Variable Valve Actuation

    SciTech Connect

    Jeffrey Gutterman; A. J. Lasley

    2008-08-31

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of the

  20. Natural Variability and Anthropogenic Trends in the Ocean Carbon Sink

    NASA Astrophysics Data System (ADS)

    McKinley, Galen A.; Fay, Amanda R.; Lovenduski, Nicole S.; Pilcher, Darren J.

    2017-01-01

    Since preindustrial times, the ocean has removed from the atmosphere 41% of the carbon emitted by human industrial activities. Despite significant uncertainties, the balance of evidence indicates that the globally integrated rate of ocean carbon uptake is increasing in response to increasing atmospheric CO2 concentrations. The El Niño–Southern Oscillation in the equatorial Pacific dominates interannual variability of the globally integrated sink. Modes of climate variability in high latitudes are correlated with variability in regional carbon sinks, but mechanistic understanding is incomplete. Regional sink variability, combined with sparse sampling, means that the growing oceanic sink cannot yet be directly detected from available surface data. Accurate and precise shipboard observations need to be continued and increasingly complemented with autonomous observations. These data, together with a variety of mechanistic and diagnostic models, are needed for better understanding, long-term monitoring, and future projections of this critical climate regulation service.

  1. Natural Variability and Anthropogenic Trends in the Ocean Carbon Sink.

    PubMed

    McKinley, Galen A; Fay, Amanda R; Lovenduski, Nicole S; Pilcher, Darren J

    2017-01-03

    Since preindustrial times, the ocean has removed from the atmosphere 41% of the carbon emitted by human industrial activities. Despite significant uncertainties, the balance of evidence indicates that the globally integrated rate of ocean carbon uptake is increasing in response to increasing atmospheric CO2 concentrations. The El Niño-Southern Oscillation in the equatorial Pacific dominates interannual variability of the globally integrated sink. Modes of climate variability in high latitudes are correlated with variability in regional carbon sinks, but mechanistic understanding is incomplete. Regional sink variability, combined with sparse sampling, means that the growing oceanic sink cannot yet be directly detected from available surface data. Accurate and precise shipboard observations need to be continued and increasingly complemented with autonomous observations. These data, together with a variety of mechanistic and diagnostic models, are needed for better understanding, long-term monitoring, and future projections of this critical climate regulation service.

  2. Grid Integration Studies: Advancing Clean Energy Planning and Deployment

    SciTech Connect

    Katz, Jessica; Chernyakhovskiy, Ilya

    2016-07-01

    Integrating significant variable renewable energy (VRE) into the grid requires an evolution in power system planning and operation. To plan for this evolution, power system stakeholders can undertake grid integration studies. This Greening the Grid document reviews grid integration studies, common elements, questions, and guidance for system planners.

  3. Workshop 3 (synthesis): climate variability, water systems and management options.

    PubMed

    Connor, R; Kuylenstierna, J

    2004-01-01

    Addressing climate variability now will better prepare us for future impacts of climate change. Sustained, multi-stakeholder dialogue at local through national levels is an approach that will reach the widest audience, helped by tools that illustrate vulnerability such as the Climate Vulnerability Index. Integrated water resources management deals with managing for variability and change and is therefore highly appropriate for dealing with climate impacts.

  4. Long-term OH variability of Miras

    NASA Astrophysics Data System (ADS)

    Etoka, S.; Le Squeren, A. M.

    2000-10-01

    We present here the results and interpretation of a long-term OH variability program conducted with the French {Nançay} Radiotelescope from 1980 to 1995. It concerns seven Mira stars: R Aql, RS Vir, S CrB, R LMi, RR Aql, U Her and UX Cyg. This study deals with the three OH maser lines observed in the Miras at 1612, 1665 and 1667 MHz. These OH variable stars have periods ranging from 290 to 580 days. The study presents the first insight of the long-term temporal behaviour of OH integrated flux variations as well as spectral component variations. The main aims are to determine the temporal behaviour of the OH maser emission and the longevity and variability of the spectral components. We find that the shapes of the OH curve are closer to the IR than the optical shapes and that the emissions at 1665 and 1667 MHz have a very similar behaviour while the emission at 1612 MHz behaves differently. The 1612 MHz emission shows smoother temporal variations and greater component longevity than the main line emission, leading to the conclusion that the 1612 MHz emission is coming from an outer part of the circumstellar shell and is more saturated than the main line emission. The study also shows the existence of inhomogeneities, especially differences between the front and back parts of the shell can be seen, and that OH variability curves undergo long term variations over several cycles.

  5. Variable forcing of the Chandler wobble

    NASA Astrophysics Data System (ADS)

    Bizouard, Christian

    2010-05-01

    The Chandler wobble (the damped free mode of the rotation axis within the Earth) is strongly irregular, exhibiting amplitude variation up to 100 mas, that is 50% of its mean value. A possible explanation is the variability of the fluid layer excitation at Chandler period (around 433 days). The later is analysed in light of the longest available angular momentum time series of the atmosphere, oceans and land mass water. In contrast with most of the related studies, the geophysical effect on polar motion is computed from the integrated solution of the Euler-Liouville equation. Then the variable effect at the Chandler period is filtered by a sliding window method and compared to the one found in observed polar motion. We show that the Chandler variability mostly originates from the combined atmospheric and oceanic forcing, as estimated from NCEP and ECCO-MIT models respectively. Atmospheric and oceanic processes account for the variable amplitude and phase over years ranging from 1948 to 2008 : decrease of the Chandler amplitude from the 1950's (250 mas) to the 1970's (120 mas), slow increase till mid 1990's (up to 200 mas), and decrease in the first decade of the twenty-first century (present amplitude is 100 mas); the phase variations, less striking, within 40° range, are as well explained. The results we obtained are confirmed by shorter sets of atmospheric and oceanic angular momentum time series.

  6. Saturn's variable magnetosphere.

    PubMed

    Gombosi, Tamas I; Hansen, Kenneth C

    2005-02-25

    Since the Cassini spacecraft reached Saturn's orbit in 2004, its instruments have been sending back a wealth of data on the planet's magnetosphere (the region dominated by the magnetic field of the planet). In this Viewpoint, we discuss some of these results, which are reported in a collection of reports in this issue. The magnetosphere is shown to be highly variable and influenced by the planet's rotation, sources of plasma within the planetary system, and the solar wind. New insights are also gained into the chemical composition of the magnetosphere, with surprising results. These early results from Cassini's first orbit around Saturn bode well for the future as the spacecraft continues to orbit the planet.

  7. Variable speed controller

    NASA Technical Reports Server (NTRS)

    Estes, Christa; Spiggle, Charles; Swift, Shannon; Vangeffen, Stephen; Younger, Frank

    1992-01-01

    This report details a new design for a variable speed controller which can be used to operate lunar machinery without the astronaut using his or her upper body. In order to demonstrate the design, a treadle for an industrial sewing machine was redesigned to be used by a standing operator. Since the invention of an electrically powered sewing machine, the operator has been seated. Today, companies are switching from sit down to stand up operation involving modular stations. The old treadle worked well with a sitting operator, but problems have been found when trying to use the same treadle with a standing operator. Emphasis is placed on the ease of use by the operator along with the ergonomics involved. Included with the design analysis are suggestions for possible uses for the speed controller in other applications.

  8. On Botulinum Neurotoxin Variability

    PubMed Central

    2015-01-01

    ABSTRACT  The rapidly growing number of botulinum neurotoxin sequences poses the problem of the possible evolutionary significance of the variability of these superpotent neurotoxins for toxin-producing Clostridium species. To progress in the understanding of this remarkable phenomenon, we suggest that researchers should (i) abandon an anthropocentric view of these neurotoxins as human botulism-causing agents or as human therapeutics, (ii) begin to investigate in depth the role of botulinum neurotoxins in animal botulism in the wilderness, and (iii) devote large efforts to next-generation sequencing of soil samples to identify novel botulinum neurotoxins. In order to compare the fitness of the different toxins, we suggest that assays of all the steps from toxin production to animal death should be performed. PMID:25564463

  9. Essential biodiversity variables

    USGS Publications Warehouse

    Pereira, H.M.; Ferrier, S.; Walters, M.; Geller, G.N.; Jongman, R.H.G.; Scholes, R.J.; Bruford, M.W.; Brummitt, N.; Butchart, S.H.M.; Cardoso, A.C.; Coops, N.C.; Dulloo, E.; Faith, D.P.; Freyhof, J.; Gregory, R.D.; Heip, C.; Höft, R.; Hurtt, G.; Jetz, W.; Karp, D.S.; McGeoch, M.A.; Obura, D.; Onada, Y.; Pettorelli, N.; Reyers, B.; Sayre, R.; Scharlemann, J.P.W.; Stuart, S.N.; Turak, E.; Walpole, M.; Wegmann, M.

    2013-01-01

    Reducing the rate of biodiversity loss and averting dangerous biodiversity change are international goals, reasserted by the Aichi Targets for 2020 by Parties to the United Nations (UN) Convention on Biological Diversity (CBD) after failure to meet the 2010 target (1, 2). However, there is no global, harmonized observation system for delivering regular, timely data on biodiversity change (3). With the first plenary meeting of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) soon under way, partners from the Group on Earth Observations Biodiversity Observation Network (GEO BON) (4) are developing—and seeking consensus around—Essential Biodiversity Variables (EBVs) that could form the basis of monitoring programs worldwide.

  10. On botulinum neurotoxin variability.

    PubMed

    Montecucco, Cesare; Rasotto, Maria Berica

    2015-01-06

    The rapidly growing number of botulinum neurotoxin sequences poses the problem of the possible evolutionary significance of the variability of these superpotent neurotoxins for toxin-producing Clostridium species. To progress in the understanding of this remarkable phenomenon, we suggest that researchers should (i) abandon an anthropocentric view of these neurotoxins as human botulism-causing agents or as human therapeutics, (ii) begin to investigate in depth the role of botulinum neurotoxins in animal botulism in the wilderness, and (iii) devote large efforts to next-generation sequencing of soil samples to identify novel botulinum neurotoxins. In order to compare the fitness of the different toxins, we suggest that assays of all the steps from toxin production to animal death should be performed. Copyright © 2015 Montecucco and Rasotto.

  11. Integrated nutrition.

    PubMed

    Allison, S P

    2005-08-01

    There is no branch of medicine in which nutritional considerations do not play some part. Overnutrition, undernutrition or unbalanced nutrition are the major causes of ill health in the world. Conversely, illness causes important nutritional and metabolic problems. The spectrum from lack to excess of nutrients is seamless as a clinical and scientific discipline, the two extremes being linked by the Barker effect by which intrauterine malnutrition and low birth weight predispose to obesity, diabetes and CVD in later life. However, the teaching of nutrition in medical and nursing schools remains sparse. Nutritional care cannot be practised satisfactorily in isolation from other aspects of management, since factors such as drugs, surgery and fluid and electrolyte balance affect nutritional status. Nutritional treatment may also have adverse or beneficial effects according to the composition, amount and mode of delivery of the diet and the clinical context in which it is given. Any benefits of nutritional support may also be negated by shortcomings in other aspects of treatment and must therefore be fully integrated into overall care. One example of this approach is the enhanced recovery after a surgery protocol incorporating immediate pre-operative carbohydrate and early post-operative oral intake with strict attention to zero fluid balance, epidural analgesia and early mobilisation. Other examples include the deleterious effect on surgical outcome of salt and water overload or hyperglycaemia, either of which may negate the benefits of nutritional support. There is a need, therefore, to integrate clinical nutrition more closely, not just into medical and surgical practice, but also into the organisation of health services in the hospital and the community, and into the training of doctors and nurses. Societies originally devoted to parenteral and enteral nutrition need to widen their scope to embrace wider aspects of clinical nutrition.

  12. Vertical integration and market power

    SciTech Connect

    Maddigan, R.J.

    1980-01-01

    One of the continuing debates of industrial organization surrounds the importance of market structure in determining a firm's performance. This controversy develops naturally from the difficulties in measuring the relevant variables and the hazards of statistical analysis. The focus of this empirical study is the relationship between vertical integration, as an element of market structure, and market power, as a component of a firm's performance. The model presented in this paper differs from previous efforts because vertical integration is measured by the Vertical Industry Connections (VIC) index. VIC is defined as a function of the relative net interactions among the industries in which a firm operates, and is calculated by use of the national input-output tables. A linear regression model is estimated by means of a random sample of firms selected from the Standard and Poor's COMPUSTAT data base for 1963, 1967, and 1972. Combined cross-sectional, time-series methods are employed. The dependent variable is the price-cost margin; the independent variables include not only VIC, but also the concentration ratio, diversification index, value of assets, capital-output ratio, and sales growth. The results indicate that VIC is significant in increasing the price-cost margin, and thus support the hypothesis that vertical integration is a strategy to enhance market power. 1 figure, 3 tables.

  13. COMPLEX VARIABLE BOUNDARY ELEMENT METHOD: APPLICATIONS.

    USGS Publications Warehouse

    Hromadka, T.V.; Yen, C.C.; Guymon, G.L.

    1985-01-01

    The complex variable boundary element method (CVBEM) is used to approximate several potential problems where analytical solutions are known. A modeling result produced from the CVBEM is a measure of relative error in matching the known boundary condition values of the problem. A CVBEM error-reduction algorithm is used to reduce the relative error of the approximation by adding nodal points in boundary regions where error is large. From the test problems, overall error is reduced significantly by utilizing the adaptive integration algorithm.

  14. Fatigue crack growth under variable amplitude loading

    NASA Astrophysics Data System (ADS)

    Sidawi, Jihad A.

    1994-09-01

    Fatigue crack growth tests were conducted on an Fe 510 E C-Mn steel and a submerged arc welded joint from the same material under constant, variable, and random loading amplitudes. Paris-Erdogan's crack growth rate law was tested for the evaluation of m and C using the stress intensity factor K, the J-integral, the effective stress intensity factor K(sub eff), and the root mean square stress intensity factor K(sub rms) fracture mechanics concepts. The effect of retardation and residual stresses resulting from welding was also considered. It was found that all concepts gave good life predictions in all cases.

  15. Fatigue crack growth under variable amplitude loading

    NASA Technical Reports Server (NTRS)

    Sidawi, Jihad A.

    1994-01-01

    Fatigue crack growth tests were conducted on an Fe 510 E C-Mn steel and a submerged arc welded joint from the same material under constant, variable, and random loading amplitudes. Paris-Erdogan's crack growth rate law was tested for the evaluation of m and C using the stress intensity factor K, the J-integral, the effective stress intensity factor K(sub eff), and the root mean square stress intensity factor K(sub rms) fracture mechanics concepts. The effect of retardation and residual stresses resulting from welding was also considered. It was found that all concepts gave good life predictions in all cases.

  16. Integrative Behavioral Couple Therapy.

    PubMed

    Christensen, Andrew; Doss, Brian D

    2017-02-01

    Integrative Behavioral Couple Therapy (IBCT) is based in part on traditional behavioral couple therapy but expands both the conceptualization of couple distress and of intervention. The efficacy of IBCT has been supported in three clinical trials, including one with five year follow-up. Additionally, the effectiveness of IBCT in the real world has been supported through a system-wide dissemination effort in the United States Department of Veteran's Affairs. The reach of IBCT has also been extended through an online program, www.OurRelationship.com, based on IBCT. A nationwide clinical trial with a representative sample of the US population demonstrated the effectiveness of this program on both relationship and individual variables.

  17. Variable Star Observing in Hungary

    NASA Astrophysics Data System (ADS)

    Mizser, Attila

    1986-12-01

    Astronomy and variable star observing has a long history in Hungary, dating back to the private observatories erected by the Hungarian nobility in the late 19th Century. The first organized network of amateur variable star observers, the Variable Star Section of the new Hungarian Astronomical Association, was organized around the Urania Observatory in Budapest in 1948. Other groups, dedicated to various types of variables, have since been organized.

  18. The variable density aircraft concept

    NASA Technical Reports Server (NTRS)

    Davenport, A. C.

    1975-01-01

    In the variable density aircraft concept the aircraft's density is varied by varying its volume. This is accomplished by combining a variable volume hull, which is called the dynapod, with intrinsic means for the controlled variation of a mass of working fluid or substance within the aircraft. The dynapod is a hinged structure and follows the volumetric variations of the working fluid. The result is a variable density hull, which with the attachment of power plants, etc., becomes a variable density aircraft.

  19. Labor Market Integration of Immigrants in France, Germany, and the United Kingdom

    DTIC Science & Technology

    2010-03-01

    variable is labor market integration. The independent variables are language acquisition , category of immigrant, integration policy, and institutional...racism. These four factors should indicate levels of labor market integration of immigrants within a state. Despite the emphasis on language acquisition and

  20. New Galactic Double Periodic Variables

    NASA Astrophysics Data System (ADS)

    Mennickent, R. E.; Rosales, J.

    2014-10-01

    We discovered two new Double Periodic Variables in the ASAS catalogue of variable stars, viz., V495 Cen and V4142 Sgr. Other 3 candidates for Double Periodic Variables were found. All systems have relatively long orbital periods. We present improved ephemerides and disentangled light curves.

  1. Preservice Teachers' Understanding of Variable

    ERIC Educational Resources Information Center

    Brown, Sue; Bergman, Judy

    2013-01-01

    This study examines the research on middle school students' understanding of variables and explores preservice elementary and middle school teachers' knowledge of variables. According to research studies, middle school students have limited understanding of variables. Many studies have examined the performance of middle school students and offered…

  2. Electrically Variable Resistive Memory Devices

    NASA Technical Reports Server (NTRS)

    Liu, Shangqing; Wu, Nai-Juan; Ignatiev, Alex; Charlson, E. J.

    2010-01-01

    Nonvolatile electronic memory devices that store data in the form of electrical- resistance values, and memory circuits based on such devices, have been invented. These devices and circuits exploit an electrically-variable-resistance phenomenon that occurs in thin films of certain oxides that exhibit the colossal magnetoresistive (CMR) effect. It is worth emphasizing that, as stated in the immediately preceding article, these devices function at room temperature and do not depend on externally applied magnetic fields. A device of this type is basically a thin film resistor: it consists of a thin film of a CMR material located between, and in contact with, two electrical conductors. The application of a short-duration, low-voltage current pulse via the terminals changes the electrical resistance of the film. The amount of the change in resistance depends on the size of the pulse. The direction of change (increase or decrease of resistance) depends on the polarity of the pulse. Hence, a datum can be written (or a prior datum overwritten) in the memory device by applying a pulse of size and polarity tailored to set the resistance at a value that represents a specific numerical value. To read the datum, one applies a smaller pulse - one that is large enough to enable accurate measurement of resistance, but small enough so as not to change the resistance. In writing, the resistance can be set to any value within the dynamic range of the CMR film. Typically, the value would be one of several discrete resistance values that represent logic levels or digits. Because the number of levels can exceed 2, a memory device of this type is not limited to binary data. Like other memory devices, devices of this type can be incorporated into a memory integrated circuit by laying them out on a substrate in rows and columns, along with row and column conductors for electrically addressing them individually or collectively.

  3. Market Designs for High Levels of Variable Generation: Preprint

    SciTech Connect

    Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

    2014-10-01

    Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

  4. Integrated power system

    SciTech Connect

    Waddington, C.

    1987-10-13

    An integrated power system is described for transmitting power from a gas turbine engine, including a gas producer and a free turbine engine, to the driving elements of a vehicle comprising: a pair of independent output shafts; a pair of combining planetary gear systems, each being drivingly coupled to an associated one of the output shafts; a variable speed transmission drivingly coupled to the free power turbine; drive means operatively connecting the transmission and each of the combining planetary gear systems; steering means operatively coupled to each of the combining planetary gear systems for selectively driving at least one of the combining planetary gear systems; the steering means including a variable displacement hydraulic motor in driving engagement with the planetary gear systems and an hydraulic pump in driving engagement with the transmission for supplying fluid under pressure to the hydraulic motor to thereby effect steering of the vehicle; a fuel control for controlling the power output of the gas turbine engine; and an adjustable relief valve operatively interposed between the hydraulic motor and the hydraulic pump, the valve being responsive to the fuel control to establish a maximum fluid pressure imparted by the hydraulic pump to the hydraulic motor.

  5. Extragalactic Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Shara, Michael M.; Neill, James D.

    2005-03-01

    SALT is uniquely poised to make major inroads in the study of extragalactic cataclysmic variables (CVs) - novae and dwarf novae. The ability to search an external galaxy for erupting CVs night after night, for months at a time, AND to obtain confirmatory spectra within a night of discovery is unique and invaluable. We present several examples of multi-week to multi-month searches for extragalactic CVs with 1 to 4 meter-class telescopes. In particular, we have detected the first erupting dwarf novae in the LMC and placed a lower limit on the number of CVs in that galaxy. We have also observed the Local Group dwarf ellipticals M32 and NGC 205 in their entirety every clear night over a 4.5 month interval. In this survey we discovered one nova each in M32 and NGC 205, far more than previous nova surveys led us to expect. A similar search in M81 again reveals more novae than expected, and demonstrates, conclusively, that novae are predominantly a bulge population in spiral galaxies. Finally we report the detection of intergalactic tramp novae in the Fornax cluster, and emphasize that these are valuable tracers of stars stripped from their hosts during galaxy harassment. The insights gained during these preliminary studies illustrate how valuable SALT campaigns on extragalactic CVs will be.

  6. Variable angle correlation spectroscopy

    SciTech Connect

    Lee, Young Kyo

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  7. Variable camshaft timing system

    SciTech Connect

    Sapienza, S.J.

    1988-05-17

    A variable camshaft timing system in combination with an internal combustion engine having at least one cylinder, a rotatable member such as a crankshaft, and an intake and exhaust valve coupled to an intake camshaft and an exhaust camshaft respectively, the system is described comprising: a pulley wheel fixedly attached at one end of each of the intake and exhaust camshafts and the crankshaft; belt means interconnecting each of the pulley wheels for transferring rotational motion from the crankshaft to the intake and exhaust camshafts; first and second idler arm means pivotally attached to the engine, each of the idler arm means having a pivoting arm, a cam follower arm and an idler wheel in operative contact with the belt means; positioning cam means operatively coupled to each of the cam follower arms of the idler arm means; a control means responsive to various engine operating parameters for generating motor control signals; and electric motor means responsive to the motor control signals and operatively coupled to rotate the positioning cams means for positioning each of the idler arm means for changing the relative rotational position between the input camshaft and the exhaust camshaft.

  8. Infinitely variable steering transmission

    SciTech Connect

    Reed, B.O.

    1989-04-04

    A steering transmission is described comprising: first and second drive units each driven at a substantially constant speed for producing respective first and second unidirectional, continuous outputs infinitely variable between a minimum speed and a maximum speed; a first output planetary gear drivingly connected to a first transmission output; a second output planetary gear set drivingly connected to a second transmission output; an input gear set; means interconnecting the first and second output planetary gear sets; means connecting the first drive unit to the first output planetary gear set; means applying the second drive unit output to the second output planetary gear set; means applying a substantially constant speed input to the input gear set; means for selectively conditioning the input gear set to drive the one output planetary gear set at a speed having a first predetermined fixed ratio to the constant speed input, whereby to operate the transmission in one speed range; and means for selectively applying the first drive unit output to second output planetary gear set, whereby to operate the transmission in another speed range different from the one speed range.

  9. Variable depth core sampler

    SciTech Connect

    Bourgeois, P.M.; Reger, R.J.

    1994-12-31

    This invention relates to a sampling means, more particularly to a device to sample hard surfaces at varying depths. Often it is desirable to take samples of a hard surface wherein the samples are of the same diameter but of varying depths. Current practice requires that a full top-to-bottom sample of the material be taken, using a hole saw, and boring a hole from one end of the material to the other. The sample thus taken is removed from the hole saw and the middle of said sample is then subjected to further investigation. This paper describes a variable depth core sampler comprimising a circular hole saw member, having longitudinal sections that collapse to form a point and capture a sample, and a second saw member residing inside the first hole saw member to support the longitudinal sections of the first member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside the the first hole saw member.

  10. Nova-like variables

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    On grounds of different observable characteristics five classes of nova-like objects are distinguished: the UX Ursae Majoris stars, the antidwarf novae, the DQ Herculis stars, the AM Herculis stars, and the AM Canum Venaticorum stars. Some objects have not been classified specifically. Nova-like stars share most observable features with dwarf novae, except for the outburst behavior. The understanding is that dwarf novae, UX Ursae Majoris stars, and anti-dwarf novae are basically the same sort of objects. The difference between them is that in UX Ursae Majoris stars the mass transfer through the accretion disc always is high so the disc is stationary all the time; in anti-dwarf novae for some reason the mass transfer occasionally drops considerably for some time, and in dwarf novae it is low enough for the disc to undergo semiperiodic changes between high and low accretion events. DQ Herculis stars are believed to possess weakly magnetic white dwarfs which disrupt the inner disc at some distance from the central star; the rotation of the white dwarf can be seen as an additional photometric period. In AM Herculis stars, a strongly magnetic white dwarf entirely prevents the formation of an accretion disk and at the same time locks the rotation of the white dwarf to the binary orbit. Finally, AM Canum Venaticorum stars are believed to be cataclysmic variables that consist of two white dwarf components.

  11. Common Variable Immunodeficiency.

    PubMed

    Saikia, Biman; Gupta, Sudhir

    2016-04-01

    Common variable immunodeficiency (CVID) is the most common primary immunodeficiency of young adolescents and adults which also affects the children. The disease remains largely under-diagnosed in India and Southeast Asian countries. Although in majority of cases it is sporadic, disease may be inherited in a autosomal recessive pattern and rarely, in autosomal dominant pattern. Patients, in addition to frequent sino-pulmonary infections, are also susceptible to various autoimmune diseases and malignancy, predominantly lymphoma and leukemia. Other characteristic lesions include lymphocytic and granulomatous interstitial lung disease, and nodular lymphoid hyperplasia of gut. Diagnosis requires reduced levels of at least two immunoglobulin isotypes: IgG with IgA and/or IgM and impaired specific antibody response to vaccines. A number of gene mutations have been described in CVID; however, these genetic alterations account for less than 20% of cases of CVID. Flow cytometry aptly demonstrates a disturbed B cell homeostasis with reduced or absent memory B cells and increased CD21(low) B cells and transitional B cell populations. Approximately one-third of patients with CVID also display T cell functional defects. Immunoglobulin therapy remains the mainstay of treatment. Immunologists and other clinicians in India and other South East Asian countries need to be aware of CVID so that early diagnosis can be made, as currently, majority of these patients still go undiagnosed.

  12. Characterization of the spatial variability of channel morphology

    USGS Publications Warehouse

    Moody, J.A.; Troutman, B.M.

    2002-01-01

    The spatial variability of two fundamental morphological variables is investigated for rivers having a wide range of discharge (five orders of magnitude). The variables, water-surface width and average depth, were measured at 58 to 888 equally spaced cross-sections in channel links (river reaches between major tributaries). These measurements provide data to characterize the two-dimensional structure of a channel link which is the fundamental unit of a channel network. The morphological variables have nearly log-normal probability distributions. A general relation was determined which relates the means of the log-transformed variables to the logarithm of discharge similar to previously published downstream hydraulic geometry relations. The spatial variability of the variables is described by two properties: (1) the coefficient of variation which was nearly constant (0.13-0.42) over a wide range of discharge; and (2) the integral length scale in the downstream direction which was approximately equal to one to two mean channel widths. The joint probability distribution of the morphological variables in the downstream direction was modelled as a first-order, bivariate autoregressive process. This model accounted for up to 76 per cent of the total variance. The two-dimensional morphological variables can be scaled such that the channel width-depth process is independent of discharge. The scaling properties will be valuable to modellers of both basin and channel dynamics. Published in 2002 John Wiley and Sons, Ltd.

  13. Demand Response and Energy Storage Integration Study

    SciTech Connect

    Ma, Ookie; Cheung, Kerry

    2016-03-01

    Demand response and energy storage resources present potentially important sources of bulk power system services that can aid in integrating variable renewable generation. While renewable integration studies have evaluated many of the challenges associated with deploying large amounts of variable wind and solar generation technologies, integration analyses have not yet fully incorporated demand response and energy storage resources. This report represents an initial effort in analyzing the potential integration value of demand response and energy storage, focusing on the western United States. It evaluates two major aspects of increased deployment of demand response and energy storage: (1) Their operational value in providing bulk power system services and (2) Market and regulatory issues, including potential barriers to deployment.

  14. SWIFT: A solar system integration software package

    NASA Astrophysics Data System (ADS)

    Levison, Harold F.; Duncan, Martin J.

    2013-03-01

    SWIFT follows the long-term dynamical evolution of a swarm of test particles in the solar system. The code efficiently and accurately handles close approaches between test particles and planets while retaining the powerful features of recently developed mixed variable symplectic integrators. Four integration techniques are included: Wisdom-Holman Mapping; Regularized Mixed Variable Symplectic (RMVS) method; fourth order T+U Symplectic (TU4) method; and Bulirsch-Stoer method. The package is designed so that the calls to each of these look identical so that it is trivial to replace one with another. Complex data manipulations and results can be analyzed with the graphics packace SwiftVis.

  15. Spectral variability on Ceres

    NASA Astrophysics Data System (ADS)

    Erard, Stéphane

    2015-04-01

    Older ground-based observations are reprocessed in order to assess the spectral variability of Ceres surface before the beginning of observations by the Dawn spacecraft. Ceres was observed with NACO on the VLT in 2004 and 2005, producing resolved spectra of the disk under different attitudes. The data cover the range from 0.91-3.80 µm (J, H, K, and L bands), except in the telluric regions. They consist in spectral scans of the dayside, typically with 15 lines of 20 samples, an actual resolution of ~ 100 km, and a spectral resolution R~500 to 1500. A specific calibration scheme has been applied to preprocess the data and to evidence small compositional variations at the surface of Ceres. The major signatures observed are two bands centered at 3.06 and 3.30 µm, which exhibit significant spatial variations at this scale (5 to 10%). These features are best fit by ammoniated minerals (phyllosilicates or feldspars), although the lack of secondary hydration bands seems to rule out phyllosilicates. No significant absorption or variation is observed in J, H and K bands, consistently with [1]. No presence of ices (H2O, C02…) is detected, even at the poles. If Ceres was once rich in ices (e.g., [2]), this suggests a global resurfacing with melting of ices in the subsurface, and alteration under the influence of H2O and perhaps NH3, with reduced production of phyllosilicates. References [1] Carry et al (2012) Icarus 217, 20 [2] McCord, T. B. and C. Sotin (2005) JGR 110, 05009.

  16. Greenland Glacier Albedo Variability

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The program for Arctic Regional Climate Assessment (PARCA) is a NASA-funded project with the prime goal of addressing the mass balance of the Greenland ice sheet. Since the formal initiation of the program in 1995, there has been a significant improvement in the estimates of the mass balance of the ice sheet. Results from this program reveal that the high-elevation regions of the ice sheet are approximately in balance, but the margins are thinning. Laser surveys reveal significant thinning along 70 percent of the ice sheet periphery below 2000 m elevations, and in at least one outlet glacier, Kangerdlugssuaq in southeast Greenland, thinning has been as much as 10 m/yr. This study examines the albedo variability in four outlet glaciers to help separate out the relative contributions of surface melting versus ice dynamics to the recent mass balance changes. Analysis of AVHRR Polar Pathfinder albedo shows that at the Petermann and Jakobshavn glaciers, there has been a negative trend in albedo at the glacier terminus from 1981 to 2000, whereas the Stor+strommen and Kangerdlugssuaq glaciers show slightly positive trends in albedo. These findings are consistent with recent observations of melt extent from passive microwave data which show more melt on the western side of Greenland and slightly less on the eastern side. Significance of albedo trends will depend on where and when the albedo changes occur. Since the majority of surface melt occurs in the shallow sloping western margin of the ice sheet where the shortwave radiation dominates the energy balance in summer (e.g. Jakobshavn region) this region will be more sensitive to changes in albedo than in regions where this is not the case. Near the Jakobshavn glacier, even larger changes in albedo have been observed, with decreases as much as 20 percent per decade.

  17. Solar Variability and Climate

    NASA Astrophysics Data System (ADS)

    Haigh, Joanna D.

    Solar radiation is the fundamental energy source for the atmosphere and the global average equilibrium temperature of the Earth is determined by a balance between the energy acquired by the solar radiation absorbed and the energy lost to space by the emission of heat radiation. The interaction of this radiation with the climate system is complex but it is clear that any change in total solar irradiance (TSI) has the potential to influence climate. In the past, although many papers were written on relationships between sunspot numbers and the weather, the topic of solar influences on climate was often disregarded by meteorologists. This was due to a combination of factors of which the key was the lack of any robust measurements indicating that solar radiation did indeed vary. There was also mistrust of the statistical validity of the evidence and, importantly, no established scientific mechanisms whereby the apparent changes in the Sun might induce detectable signals near the Earth's surface. Another influence was a desire by the meteorological profession to distance itself from the Astrometeorology movement popular in the 19th century (anderson1999). Nowadays, with improved measurements of solar and climate parameters, evidence for an influence of solar variability on the climate of the lower atmosphere has emerged from the noise. This article provides a brief review of the observational evidence and an outline of the mechanisms whereby rather small changes in solar radiation may induce detectable signals near the Earth's surface is not possible to review here all potential mechanisms for solar-climate links. What is presented offers, necessarily, a personal perspective but, of the areas that are not covered, two may be pertinent: the effects of solar energetic particles on stratospheric composition (see e.g. jackman et al. 2005) and the possible influence of galactic cosmic rays on clouds through ionisation processes (see Marsh, this volume).

  18. Finite element implementation of state variable-based viscoplasticity models

    NASA Technical Reports Server (NTRS)

    Iskovitz, I.; Chang, T. Y. P.; Saleeb, A. F.

    1991-01-01

    The implementation of state variable-based viscoplasticity models is made in a general purpose finite element code for structural applications of metals deformed at elevated temperatures. Two constitutive models, Walker's and Robinson's models, are studied in conjunction with two implicit integration methods: the trapezoidal rule with Newton-Raphson iterations and an asymptotic integration algorithm. A comparison is made between the two integration methods, and the latter method appears to be computationally more appealing in terms of numerical accuracy and CPU time. However, in order to make the asymptotic algorithm robust, it is necessary to include a self adaptive scheme with subincremental step control and error checking of the Jacobian matrix at the integration points. Three examples are given to illustrate the numerical aspects of the integration methods tested.

  19. Solving Second-Order Differential Equations with Variable Coefficients

    ERIC Educational Resources Information Center

    Wilmer, A., III; Costa, G. B.

    2008-01-01

    A method is developed in which an analytical solution is obtained for certain classes of second-order differential equations with variable coefficients. By the use of transformations and by repeated iterated integration, a desired solution is obtained. This alternative method represents a different way to acquire a solution from classic power…

  20. Small stream ecosystem variability in the Sierra Nevada of California

    Treesearch

    C.T. Hunsaker; S.M. Eagan

    2003-01-01

    The quality of aquatic and riparian ecosystems is a function of their condition and the integrity of adjacent uplands in their watersheds. While small streams make up a large proportion of the overall stream network, our knowledge of how they function is still limited. The Kings River Experimental Watershed (KREW) was initiated in 2000 to quantify the variability in...